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Urumqi is located in the arid region of northwestern China, known for being one of the most delicate ecological environments and an area susceptible to climate change. The urbanization of Urumqi has progressed rapidly, yet there is a lack of research on the urbanization effect (UE) in Urumqi in terms of the regional climate. This study investigates the UE of Urumqi (urban built-up area) on the regional thermal environment and its mechanisms for the first time, based on the WRF (Weather Research and Forecasting) model (combined with the Urban Canopy Model, UCM) simulation data of 10 consecutive years (2012–2021). The results show that the UE on surface temperature (Ts) and air temperature at 2 m (T2m) is strong (weak) during the night (daytime) in all seasons, and the UE on these is largest (smallest) in spring (winter). In addition, the maximum UE on both Ts and T2m is present over southern Urumqi in winter, whereas the maximum UE is identified over the northern Urumqi in other seasons. The maximum UE on Ts occurred in northwestern Urumqi at 18 LST (Local Standard Time, i.e., UTC+6) in autumn (reaching 5.2 °C), and the maximum UE on T2m occurred in northern Urumqi at 4 LST in summer (reaching 2.6 °C). Urbanization showed a weak cooling effect during daytime in summer and winter, reflecting the unique characteristics of the UE in arid regions, which are different from those in humid regions. The maximum cooling of Ts occurred in northern Urumqi at 11 LST in summer (reaching −0.4 °C), while that of T2m occurred at 10 LST in northern and northwestern Urumqi in winter (reaching −0.25 °C), and the cooling effect lasted for a longer period of time in summer than in winter. The UE of Urumqi causes the increase of Ts mainly through the influence of net short-wave radiation and geothermal flux and causes the increase of T2m through the influence of sensible heat flux and net long-wave radiation. The UE on the land surface energy balance in Urumqi can be used to explain the seasonal variation and spatial differences of the UEs on the regional thermal environment and the underlying mechanism. [ABSTRACT FROM AUTHOR]

Changes in precipitation and its causes under future warming scenarios in Northwest China are of great concern. Based on the dynamical downscaling results of the Weather Research and Forecasting model (WRF), this study quantitatively identified the contribution of local evaporation and external moisture transport to future precipitation changes in western and eastern Northwest China (WNWC and ENWC) by calculating the precipitation recycling ratio (PRR). The results showed that the WRF could reasonably reproduce the observed spatial and temporal distribution of precipitation and evaporation during the historical reference period of 1985–2014. Under the 1.5 and 2.0°C stabilized warming scenarios from 2071 to 2100, there is a stronger precipitation growth in WNWC than in ENWC, and the PRR generally increases in WNWC and decreases in ENWC. Further analysis indicates that external moisture transport is the dominant contributor to the increased precipitation in all cases with its contribution exceeding 70%, while the difference of precipitation growth in two sub‐regions arises from the summer moisture transport at the southern boundary as the inflow in WNWC and outflow in ENWC. Compared to the negligible contribution of evaporation in ENWC (less than 7%), evaporation contributes more than 23% to the precipitation increase in WNWC under future warming scenarios, which may be related to the strong land‐atmosphere coupling there. Furthermore, an additional warming of 0.5°C leads to an increase in precipitation for both sub‐regions, which is mainly due to the contribution of external moisture transport. Plain Language Summary: In this study, we discuss the relative contributions of evaporation and moisture transport to precipitation changes in Northwest China under 1.5/2.0°C stabilized warming scenarios. With Northwest China (NWC) dividing it into two sub‐regions of western and eastern parts, we find that although the western NWC has less precipitation during the reference period of 1985–2014, the increase in precipitation is about twice that of the eastern NWC under the warming scenarios. The contribution of evaporation to the increased precipitation is greater in the western NWC compared with the reference period, which may indicate the accelerating hydrological cycle in western NWC. Moisture transport is the main contributor to the increase in precipitation and is also the main reason for the difference in precipitation changes between the two sub‐regions, mainly due to differences in summer moisture transport across the southern boundary. This work provides a scientific basis for assessing water resources in Northwest China under future warming scenarios. Key Points: External moisture transport contributes more than 70% of precipitation in Northwest China, both in terms of mean and variabilityContribution of evaporation to the precipitation increase is stronger in western Northwest China, due to its strong land‐atmosphere couplingThe difference in moisture transport between the two regions is mainly due to changes in southern border moisture transport in summer [ABSTRACT FROM AUTHOR]

In this study, we performed a high‐resolution simulation using the Weather Research and Forecasting model, integrated with water vapor tracers, covering the years 2005–2019. Our objective was to obtain deeper insights into the spatiotemporal dynamics of external advected and local evaporative water vapor, and to elucidate their impact on precipitation patterns across the Tibetan Plateau (TP). Our findings underscore that a significant proportion of TP's precipitation originates from external advected water vapor, primarily entering through the western and southern boundaries. During summer, stronger zonal and meridional water vapor transport, driven by prevailing westerly winds and the Asian monsoon, significantly influences seasonal and spatial precipitation variations. Additionally, we observed that the inter‐annual variation of precipitation is intricately linked to changes in the net water vapor influx, modulated by alterations in atmospheric circulation. We also analyze the Precipitation Recycling Ratio (PRR) which refers to the proportion of precipitation originated from local evaporative water vapor to the total precipitation, revealing distinctive elevation‐dependent variations aligned with grassland distribution. Notably, PRR exhibits asynchronous shifts with precipitation at different timescales, potentially linked to soil moisture‐precipitation feedback at intra‐annual scales. Moreover, the investigation highlights that inter‐annual variations in PRR are primarily linked to the inflow and outflow of water vapor as well as wind strength at 500 hPa, particularly prominent during colder seasons, while thermal factors carry comparable weight to dynamical factors in warmer seasons. Plain Language Summary: Precipitation constitutes a vital component of the complex climatic conditions as well as the hydrological cycle over the Tibetan Plateau (TP), known as the "Asian Water Tower." Its distinct spatiotemporal variations, closely tied to the advected water vapor from external areas as well as evaporated within the TP, have direct impacts on local ecosystem and downstream water supply. These effects have profound socio‐economic and environmental consequences. In this study, we found that temporal variations and spatial inhomogeneities in precipitation are primarily impacted by the advection of external water vapor, mainly through atmospheric circulation. Additionally, about 18.9% of the annual precipitation stems from local evaporation, as indicated by the precipitation recycling ratio, which reflects the strength of regional land‐atmospheric interactions. Precipitation recycling processes are likely influenced by precipitation through soil moisture at intra‐annual timescale, but are notably impacted by the inflow of water vapor and wind strength at inter‐annual timescale. These results provide valuable insights into understanding precipitation variations at different spatiotemporal scales and contribute to more effective water resources management over the TP. Key Points: Precipitation recycling ratio (PRR) over the Tibetan Plateau exhibits significant variations both with elevation and from year to yearThe inter‐annual variation of precipitation is strongly influenced by the net influx of water vapor and associated atmospheric circulationsInter‐annual variation in PRR is significantly influenced by the inflow of water vapor and wind strength, especially during colder seasons [ABSTRACT FROM AUTHOR]

With the rapid global warming in recent decades, the Tibetan Plateau (TP) has suffered severe impacts, such as glacier retreat, glacial lake expansion, and permafrost degradation, which threaten the lives and properties of the local and downstream populations. Regional Reanalysis (RR) is vital for TP due to the limitations of observations. In this work, a 62-year (1961–2022) long atmospheric regional reanalysis with spatial resolution of 9 km (convective gray-zone scale) and temporal resolution of 1 hour over the TP (TPRR) was developed using the Weather Research and Forecasting (WRF) model, combined with re-initialization method, spectral nudging (SN), and several optimizations. TPRR is forced by ERA5 at hourly intervals. TPRR outperforms ERA5, realistically capturing climatological characteristics and seasonal variations of precipitation and T2m (air temperature at 2m above ground level). Moreover, TPRR better reproduces the frequency and intensity of precipitation, as well as the diurnal cycle of precipitation. This study also quantifies the wetting trend of 0.0071 mm/year over the TP amid global warming using TPRR. [ABSTRACT FROM AUTHOR]

Diurnal temperature range (DTR), as a core indicator of the Earth system, exhibits obvious temporal and spatial variations, which is not entirely consistent over global. The historical simulation capabilities of 19 Coupled Model Intercomparison Project 6 (CMIP6) models for DTR were firstly evaluated against CRU_TS v4.04 data. Future changes under three shared socioeconomic pathways (SSP1-2.6, SSP2-4.5, SSP5-8.5) in DTR were projected using a multi-model ensemble mean (MME), and its interannual variations were seasonally explored through empirical orthogonal function (EOF) analysis. The results indicated that CMIP6 models could reflect the decreasing trend of DTR during 1901–2014, with the global spatial correlation coefficient between models and observation ranging from 0.4 to 0.7. MME outperformed individual models in both spatial and temporal variations, indicating higher accuracy and reliability. The future changes of DTR exhibited significantly decrease across the northern hemisphere and increase in the South America, and change magnitude enlarged with time extension and emission intensity, especially by more than 0.4 °C under SSP5-8.5. The decreasing trend of global DTR was kept in SSP2-4.5 and SSP5-8.5, while SSP1-2.6 changed increasing trend during 2015–2100. DTR showed seasonal variations and was mainly influenced by colder months. The dominant modes of interannual DTR and their relationship with the 500 hPa geopotential height, the 200 hPa U wind, and the outgoing longwave radiation showed higher features in tropical regions. The highly positive correlation between the first mode of DTR and the Niño3.4 index in December/January/February (DJF) is 0.67, indicating significant influence of the El Niño-Southern Oscillation on DTR. [ABSTRACT FROM AUTHOR]

Results from eight regional climate models (RCMs) participating in the Impact of Initialized Land Temperature and Snowpack on Sub-seasonal to Seasonal Prediction (LS4P) initiative of the Global Energy and Water Exchanges (GEWEX) are examined and compared with observations over the Tibetan Plateau (TP). The RCM common domain covers most areas of East Asia with a horizontal resolution of 20–30 km. The model simulation covers a period from April to September in each year between 1991 and 2015. This study explores the RCMs' ability for seasonal climate simulation over the TP, focusing on the summer monsoon climate as part of the LS4P initiative. An intercomparison is made among eight RCMs for precipitation, surface air temperature, mid-troposphere atmospheric circulation, moisture conditions, and surface energy fluxes. It shows that the downscaling characteristics differ significantly between two major RCM types. The RegCM4 models show positive precipitation biases over the entire TP, especially over the south and southeast TP, while the WRF models mostly show both positive and negative precipitation biases over the TP with relatively high spatial correlation between simulated and observed precipitation. The multi-model ensemble mean produces overall smaller precipitation biases than most individual RCMs, with the largest biases over the southeastern TP, and smaller surface air temperature biases over most areas of the TP, especially over the central and southwestern TP. Moreover, the ensemble mean can better reproduce the inter-annual variation of precipitation and surface air temperature than most RCMs with proper magnitude. Sensitivity analyses using RegCM4 with different physics parameterizations show that varying land and cumulus schemes may induce large precipitation differences over the TP by affecting moisture and atmospheric circulation conditions in the lower and upper troposphere, respectively. Moreover, turbulent heat and radiation fluxes differences are associated with the temperature differences between different RegCM4 models. [ABSTRACT FROM AUTHOR]

Mesoscale convective systems (MCSs) are crucial in modifying the water cycle and frequently induce high‐impact weather events over eastern China. Radar and Climate Prediction Center (CPC)‐4 km satellite‐derived infrared cloud top temperature (Tb) data were used to thoroughly analyze the long‐term climatology of MCSs over eastern China, particularly in the Yangtze–Huaihe River Basin (YHR) in the warm season from 2013 to 2018. For the first time, we contrasted the effects of data set selection and threshold setting on research outcomes. The large‐scale environments of MCSs initiation were also investigated using the latest global reanalysis data ERA5. It is found that striction of thresholds, including duration, reflectivity/Tb, area, and linearity, would lead to a greater proportion of early‐morning MCSs. Satellite‐identified MCSs differed from radar‐derived ones, exhibiting afternoon diurnal peaks, faster movement speeds, longer travel distances, and expansive impact areas. The center of MCS and related precipitation shifted northward from Pre‐Meiyu to Post‐Meiyu seasons, contributing to up to 20% of total rainfall, with most MCSs moving along eastward trajectories. MCSs typically had the most substantial impact in the Meiyu season because of the most prolonged duration, largest convective core area, and strongest precipitation intensity. Warm‐season MCSs initiated ahead of midlevel troughs and were related to strong anomalous low‐level convergence and midlevel upward. The circulation anomalies were the strongest in the Pre‐Meiyu season among the three subseasons, with most moisture sourced from the southwest. Plain Language Summary: This work used radar and satellite data to analyze the climate characteristics of a kind of large thunderstorms known as mesoscale convective systems (MCSs) in the Yangtze–Huaihe River Basin (YHR) in eastern China. These systems cover large areas, lasting from a few hours to a few days. The analysis revealed that stricter tracking thresholds would lead to more early‐morning MCSs. Satellite‐identified MCSs differed from those identified by radar. They tended to have more thunderstorms in the afternoon, move faster, travel longer distances, and cover larger areas. MCSs also contributed to up to 20% of the total warm‐season rainfall in the YHR. MCSs typically had the most substantial impact in the rainy season of eastern China from mid‐June to mid‐July. Warm‐season MCSs initiated ahead of low‐pressure systems and were related to strong anomalous low‐level convergence and midlevel upward motion. During the time before the rainy season, the large‐scale forcing needed to be anomaly enough to trigger MCS formation. Most of the moisture that caused MCSs came from southwest direction instead of stemming locally during this period. Key Points: Six‐year climatology of warm‐season mesoscale convective systems (MCSs) in Yangtze–Huaihe River Basin is investigated using satellite, radar data, and ERA5Criteria setting for tracking MCSs noticeably influences the derived featuresMeiyu season MCSs featured longest duration, largest areas, and heaviest precipitation, while the background circulation anomalies are the weakest [ABSTRACT FROM AUTHOR]

Compound wind and precipitation extremes (CWPEs) amplify risk to human health, socio‐economic and ecological systems relative to their single extreme meteorological events. Given the rise in weather and climate extremes resulting from global warming, it is crucial to evaluate the ability of the Coupled Model Intercomparison Project Phase 6 (CMIP6) models to capture this bivariate compound event and explore projected changes of CWPEs in the future under different climate‐change scenarios—the Shared Socioeconomic Pathway (SSP) scenarios. In this study, we first evaluate 14 CMIP6 models at a global scale using the ERA5 reanalysis data set spanning 1979–2014. Overall, some of the CMIP6 models, especially the multi‐model ensemble mean (MMEM), can reasonably capture CWPEs during the historical period, with more CWPEs in the northern and southern hemispheres during their respective cold seasons. However, the MMEM tends to overestimate CWPEs in some land areas and show underestimation in some oceanic regions. Then we compute projected changes of CWPEs in periods 1 (2041–2070) and 2 (2071–2100) under SSP1‐2.6, SSP2‐4.5 and SSP5‐8.5 scenarios. Low emission scenarios effectively mitigate the long‐term increase in future CWPEs. The occurrence of CWPEs will change significantly with the increase of emissions during period 2, particularly in polar regions. Finally, we quantify the uncertainty for global future projections of CWPE changes. The main sources of uncertainty are internal variability and model uncertainty, but the contribution of scenario uncertainty will increase as time progresses. Overall, our results provide useful information to cope with CWPEs' global impact, emphasizing the importance of incorporating the compound nature of weather and climate extremes in future climate projections. [ABSTRACT FROM AUTHOR]

U-Net, a deep-learning convolutional neural network, is used to downscale coarse meteorological data. Based on 19 models from the Coupled Model Intercomparison Project Phase 6 and the Multi-Source Weather (MSWX) dataset, bias correction and UNet downscaling approaches are used to develop high resolution dataset over the East Asian region, referred to as Climate Change for East Asia with Bias corrected UNet Dataset (CLIMEA-BCUD). CLIMEA-BCUD provides nine meteorological variables including 2-m air temperature, 2-m daily maximum air temperature, 2-m daily minimum air temperature, precipitation, 10-m wind speed, 2-m relative humidity, 2-m specific humidity, downward shortwave radiation and downward longwave radiation with 0.1° horizontal resolution at daily intervals over the historical period of 1950–2014 and three future scenarios (SSP1-2.6, SSP2-4.5 and SSP5-8.5) of 2015–2100. Validation against MSWX indicates that CLIMEA-BCUD shows reasonable performance in terms of climatology, and it is capable of simulating seasonal cycles and future changes well. It is suggested that CLIMEA-BCUD can promote the application of deep learning in climate research in the areas of climate change, hydrology, etc. [ABSTRACT FROM AUTHOR]

Climate models often overestimate the precipitation in western Tibetan Plateau (TP) during winter, due to their poor ability in representing the orographic drag of unresolved complex terrain. In this study, the parameterization scheme of orographic gravity wave drag (OGWD) in the Model for Prediction Across Scales (MPAS) is revised to account for the nonhydrostatic effects (NHE) on the surface momentum flux of vertically‐propagating orographic gravity waves (OGWs). The effect of revised OGWD scheme on the simulation of winter precipitation over the TP is examined using parallel numerical experiments with the original and revised schemes, respectively. The results show that the revised scheme can effectively alleviate the precipitation biases in western TP by improving the atmospheric circulation and water vapor transport (WVT). The NHE reduces the surface wave momentum flux of OGWs which results in weaker zonal OGWD in the mid‐low troposphere and thus stronger westerlies over the TP, reducing the easterly biases in the experiment with the original OGWD scheme. The weakened zonal OGWD promotes a plateau‐scale cyclonic circulation to the north of the TP, which suppresses the northern branch of the bifurcated westerlies detouring the TP. According to quantitative analysis, the WVT into the western TP and surrounding areas by upstream westerlies is notably reduced by the northeasterlies of the cyclonic circulation, which eventually leads to the decrease of precipitation in this region. Plain Language Summary: Precipitation over the TP greatly affects the regional hydrological cycle and has profound climate and socio‐economic implications. However, the winter precipitation in western TP is commonly overestimated in the state‐of‐the‐art climate models given their poor ability in representing the orographic drag effect of unresolved complex terrain. This study revises the parameterization scheme of OGWD in the Model for Prediction Across Scales (MPAS) by accounting for the nonhydrostatic effects on the upward‐propagating OGWs. The revised scheme is found to weaken the OGWD over the TP and enhance the westerlies. A plateau‐scale cyclonic circulation is induced to the north of the TP which suppresses the blocking and deflection of westerlies caused by the high terrain in western TP. Consequently, the water vapor transport by upstream westerlies is reduced, which effectively alleviate the precipitation biases in western TP. Key Points: Winter precipitation biases in western Tibetan Plateau (TP) are reduced using a nonhydrostatic orographic gravity wave drag (OGWD) schemeAccounting for the nonhydrostatic effects produces weaker zonal OGWD which induces a plateau‐scale cyclonic circulation to the north of TPThe cyclonic circulation counters the northern branch of bifurcated westerlies, leading to a reduced water vapor transport into western TP [ABSTRACT FROM AUTHOR]

Introduction: Tofacitinib, a selective inhibitor of JAK1 and/or JAK3, is considered to alleviate the pulmonary condition of primary Sjögren's syndrome (pSS)-associated interstitial lung disease (ILD) through its anti-inflammatory and antifibrotic effects. Methods and analysis: This is a single-center, prospective, randomized, open-label trial. The trial will compare a 52-week course of oral tofacitinib with traditional therapy cyclophosphamide (CYC) combined with azathioprine (AZA) in the treatment of pSS-ILD. A total of 120 patients will be randomly assigned into two treatment groups with a 1:1 ratio and followed for 52 weeks from the first dose. The primary endpoint of the study is the increase of forced vital capacity (FVC) at 52 weeks. Secondary endpoints include high-resolution computed tomography (HRCT), diffusion capacity for carbon monoxide of the lung (DLCO), the Mahler dyspnea index, the health-related quality of life (HARQoL) score, the cough symptom score, EULAR Sjögren's syndrome disease activity index (ESSDAI), and safety. Discussion: This study will be the first randomized controlled trial to investigate tofacitinib compared to the traditional regimen of CYC in combination with AZA in the treatment of pSS-ILD, which will provide data on efficacy and safety and further elucidate the role of the JAK-STAT signaling pathway in the development of pSS-ILD. Ethics and dissemination: Before starting the experiment, the research proposal, informed consent (ICF) and relevant documents in accordance with the ethical principles of the Helsinki Declaration and the relevant requirements of the local GCP rules for ethical approval shall be submitted to the ethics committee of the hospital. The ethical approval of this study is reviewed by the Ethics Committee of Tongji Hospital and the ethical approval number is 2021-LCYJ-007. When the experiment is completed, the results will also be disseminated to patients and the public through publishing papers in international medical journals. Trial registration: The study was registered on the Chinese Clinical Trial Registry, www.chictr.org.cn; ID ChiCTR2000031389. [ABSTRACT FROM AUTHOR]

To mitigate climate warming, many countries have committed to achieve carbon neutrality in the mid-21st century. Here, we assess the global impacts of changing greenhouse gases (GHGs), aerosols, and tropospheric ozone (O3) following a carbon neutrality pathway on climate and extreme weather events individually using the Community Earth System Model version 1 (CESM1). The results suggest that the future aerosol reductions significantly contribute to climate warming and increase the frequency and intensity of extreme weathers toward carbon neutrality and aerosol impacts far outweigh those of GHGs and tropospheric O3. It reverses the knowledge that the changing GHGs dominate the future climate changes as predicted in the middle of the road pathway. Therefore, substantial reductions in GHGs and tropospheric O3 are necessary to reach the 1.5 °C warming target and mitigate the harmful effects of concomitant aerosol reductions on climate and extreme weather events under carbon neutrality in the future. Future aerosol reductions significantly contribute to climate warming and increase the frequency and intensity of extreme weather toward carbon neutrality. Aerosol impacts far outweigh those of greenhouse gases and tropospheric ozone. [ABSTRACT FROM AUTHOR]

This study aimed to explore the predictability of the most long‐lived tropical cyclone (TC) Freddy in 2023 while it traversed westward across the southern tropical Indian Ocean during the first 18 days of its existence. Global ensemble forecasts revealed southward track deflection and intensity underestimation of Freddy. We identified three key factors contributing to the limited predictability of Freddy, which are associated with the Mascarene High, Storm Dingani, and Freddy itself. The large track errors of Freddy can be attributed to the underestimated strength of the Mascarene High, the more northeastern position of Dingani, and the presence of excessively large or small sizes of Freddy. These findings were further validated through a high‐resolution regional model. Specifically, Freddy's track and intensity most closely matched the observations when these three factors were most closely represented. It underscores the pivotal role played by the interaction between TCs and multi‐scale systems in TC forecasts. Plain Language Summary: In 2023, Storm Freddy emerged as the most long‐lived tropical cyclone (TC) in record, lasting 35 days over the southern tropical Indian Ocean and spanning both weather and sub‐seasonal to seasonal time ranges. The primary objective of this study is to understand the factors contributing to the poor predictability of Freddy in forecasts spanning over 2 weeks. This holds significant importance as our understanding about the ability of the numerical models to predict long‐lived TCs remains limited. Using over 7,000 global ensemble forecasts from five global Numerical Weather Prediction (NWP) centers and a high‐resolution regional model, we identified three key factors contributing to the limited predictability of Freddy: the strength of the Mascarene High, the position of Storm Dingani (2023), and the size of Freddy. In large track‐error results of the global forecasts and regional simulations for Freddy, the strength of the Mascarene High was underestimated, Dingani was located further northeast, and Freddy was either too large or too small. Our investigation emphasizes the crucial role played by the interaction between the TC and multi‐scale systems in TC forecasts. This is meaningful for the improvement of Numerical Weather Prediction models to deal with extreme TC events in the future. Key Points: Due to the long lifespan of Storm Freddy, many forecasting challenges across several numerical models aroseThe limited predictability of Freddy was related to the underestimated Mascarene High and the more northeastern position of Storm DinganiThe inaccurately forecasted size of Freddy, whether excessively large or small, also contributed to the large track errors [ABSTRACT FROM AUTHOR]

Tropical cyclones (TCs) simulated at gray-zone resolution (9 km) in the Advanced Research version of the Weather Research and Forecasting Model (WRF-ARW) are evaluated over the Western North Pacific (WNP) during 11-year (2008–2018) TC seasons (June–November). The effects of the cumulus parameterization (CPS) are tested with two sets of numerical experiments: one involving CPS (ICPS) and one without (NICPS). Through comparisons with the observation and reanalysis, it is shown that the ICPS experiment yields good skills in simulating TC frequency due to more realistic large-scale mean states, including stronger low-tropospheric circulation, wetter mid-tropospheric environment, and stronger ascending motion over the TC main development region (MDR). On the other hand, the NICPS experiment is found to better reproduce intense TCs (Saffir–Simpson hurricane categories 3, 4 and 5) in terms of intensity, accumulated cyclone energy (ACE), and inner-core size. NICPS can also reasonably capture TC inner-core structure with stronger radial inflow in the boundary layer, rising motion around the eyewall and outflow in the mid to upper troposphere. Nevertheless, NICPS significantly underestimates TC outer size due to rapidly decay of TC outer wind field, suggesting limited severe convective activities in the outer region. [ABSTRACT FROM AUTHOR]

The spatiotemporal characteristics of subdaily extreme precipitation over the Tibetan Plateau (TP) have undergone significant changes due to global warming. In this study, we employed the high‐resolution Weather Research and Forecasting regional climate model to conduct a series of historical and projection simulations under representative concentration pathways (RCPs), especially RCP4.5 and RCP8.5. The aim was to investigate the past and future climatologies and spatiotemporal evolution of subdaily precipitation extremes using newly proposed subdaily extreme precipitation indices (EPIs). The results show that projected changes in precipitation amount, particularly during wet hours, exhibit spatial disparaties. Notably, there are significant decreases along the southern border of the TP and over the western TP, while obvious increases are observed over the inner TP. The southeastern TP, western TP, and southern border of the TP are expected to experience less frequent, shorter duration, and more intense precipitation on an hourly basis. The TP, as a whole, has demonstrated significantly increasing trends in moderate‐to‐heavy precipitation frequencies, along with consistent decreasing trends in precipitation events with short, medium, and long durations. Furthermore, it is predicted that the relationship between extreme precipitation and temperature will deviate from the Clausius‐Clapeyron (C‐C) relationship toward the double C‐C relationship in the far‐future under RCP8.5, particularly over the southeastern TP. Additionally, there are robust correlations between the intensity‐related EPIs and elevation. This indicates that, at the local scale, the complex topography of the region may play a crucial role in shaping the nonuniform distribution of precipitation extremes by modulating associated upward motion. Plain Language Summary: The Tibetan Plateau (TP) has experienced substantial warming during the past decades, at a rate twice that of the global average due to its unique location and elevated terrain. Warming has significantly changed the amount, intensity, frequency, and extremes of precipitation over the TP. The changes in precipitation would influence the stability of the local ecoenvironment and the development of agriculture and industry directly. Previous studies have shown the big picture of daily precipitation extremes in the future, but the characteristics of precipitation extremes at hourly timescale are unclear. This study simulates the changes in subdaily precipitation extremes in the historical (1980–2005) and future (2006–2099) periods under different climate scenarios (RCP4.5 and RCP8.5). Our results show that the spatiotemporal changes and variability over the western TP, the southern border of TP and the southeastern TP are more dramatic than that over the central TP. The southeastern TP shows higher sensitivity and vulnerability to subdaily precipitation extremes and may experience less frequent precipitation lasting for a shorter duration, but with stronger intensity at hourly timescale. The results of this study can guide adaptive measures and be helpful for long‐term water resource management over the TP. Key Points: The simulated hourly precipitation over the Tibetan Plateau (TP) is characterized by heterogeneity and spatially disparate changesLess frequent, shorter duration, and more intense precipitation over the southeastern and the southern border of the TP are projectedThe distributions of the intensity‐related indices exhibit a dependency on elevation [ABSTRACT FROM AUTHOR]

On 13 November 2019, seven commercial aircraft of China Eastern Airlines encountered nine severe-or-greater clear-air turbulence (CAT) events over central and eastern China within 12 h (0000–1200 UTC). These events mainly occurred at altitudes between 6.0 and 6.7 km. A high-resolution nested numerical simulation is carried out using the Weather Research and Forecasting (WRF) Model to investigate the generation mechanism of these CAT events, with a horizontal resolution of 1 km over the inner domain. In addition, seven CAT diagnostics with outstanding performances are employed for the mechanism analysis. The WRF Model can reasonably reproduce both synoptic-scale systems (Siberian high and upper-level jet stream) and local vertical structures (temperature, dewpoint temperature, and wind field). The simulation indicates that an upper-level front–jet system with a remarkable meridional temperature gradient intensifies over central and eastern China, with the maximum wind speed increasing from 59.0 to 67.3 m s−1. The intensification of the front–jet system induces the tropopause folding, and nine localized CAT events occur in the region with large vertical wind shear (VWS) (1.55 × 10−2–2.53 × 10−2 s−1) and small Richardson numbers (Ri) (0.42–0.85) below the cyclonic side of the jet stream. Diagnostic analysis reveals that Kelvin–Helmholtz instability plays an important role in CAT generation, while convective and inertial instability is not directly associated with CAT generation in this study. A typical flight case with continuous CAT events also suggests that large VWS (greater than 1.3 × 10−2 s−1) accompanied with small Ri (less than 1) favors CAT generation in a front–jet system environment. Significance Statement: A high-resolution nested numerical simulation is carried out using the Weather Research and Forecasting (WRF) Model to investigate the generation mechanism of nine severe-or-greater clear-air turbulence (CAT) events over central and eastern China. Intensification of a front–jet system induces tropopause folding, and nine CAT events occur in the region with large vertical wind shear (greater than 1.55 × 10−2 s−1) and small Richardson numbers (less than 0.85) below the cyclonic side of the jet stream. Kelvin–Helmholtz instability plays an important role in the CAT generation, rather than convective and inertial instability. [ABSTRACT FROM AUTHOR]

Vegetation is one of the most important parts of the Earth's land surface system. To investigate the impact and uncertainty of multi-source vegetation data on climate simulations in East Asia, we have compared two Fractional Vegetation Cover (FVC) and five Leaf Area Index (LAI) products and then performed seven experiments from 1999 to 2018 with the WRF model. The results suggest that the sensitivity of vegetation climatology is large especially in south East Asia, with a maximum difference of 4 m2/m2 in LAI and 16% in FVC. For the mean temperature, the responses in East Asia are between ± 0.4 K, and the uncertainty over the Chinese Mainland gradually enhances with the rapid vegetation growth. The feedback of precipitation is highly heterogeneous with sensitivities ranging between ± 1 mm. For interannual variability, vegetation has a greater impact in summer and autumn. The uncertainty of temperature and precipitation in summer over the Chinese Mainland is 118 and 1754 times that in winter. In addition, the linear trend results also indicate that the maximum trend difference in temperature is around 0.04 K/a in eastern China, while the precipitation has a larger range of 0.04–0.10 mm/a in southern East Asia. Besides, the biophysical mechanism analysis suggests that vegetation impact on surface energy budget is mainly a competition between albedo feedback and moisture feedback, and the large differences in multi-source FVC and LAI are sufficient to simulate different or even opposite feedbacks. [ABSTRACT FROM AUTHOR]

Air turbulence, especially the clear-air turbulence (CAT), always affects flight safety. Based on six CAT diagnostics and ERA5 reanalysis data, the spatiotemporal characteristics of CAT potential in the middle and upper troposphere in China during 1979–2020 and the possible mechanisms are analyzed in this study. The results show that CAT occurs the most frequently in winter and spring at 250–300 and 200–225 hPa, respectively. In general, CAT occurs relatively less in summer and autumn. Moreover, the CAT potential decreases with altitude in each season, and the high-magnitude centers gradually move northward and eastward accompanied with a rising motion from winter to summer. During 1979–2020, the CAT potential shows clear increasing trends in most of China in winter, while decreasing trends in most regions in summer. In the "high CAT frequency region (HCFR, 75–135° E, 25–45° N)", the CAT potential has been significantly increasing in winter and decreasing in summer. Mechanism analysis indicates that the spatiotemporal distribution of East Asian subtropical westerly jet is well correlated with the CAT potential in the HCFR, with the spatial (temporal) correlation coefficients greater than 0.75 (0.54). In addition, the geopotential height pattern in various regions, the zonal circulation in the Eurasia and Atlantic, the Polar Vortex, the Subtropical High, and the sea surface temperature all have significant impact on the CAT in the HCFR. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP), also called the Third Pole, is considered to be "the world water tower". The northwestern TP (NWTP), which has an average elevation higher than 4800 m, is an arid region where the summer precipitation is largely overestimated by the ERA5 global reanalysis product. We hypothesize that this wet bias is mainly caused by unrealistic lower-level winds that trigger strong convection over the region; it can be reduced by using a high-resolution regional climate model with a large domain that allows realistically representing interactions between the Westerlies and Asian summer monsoons. Here, downscaling using the Weather Research and Forecasting (WRF) model driven by ERA5 was conducted with a large domain (8°‒50° N, 65°‒125° E) at 9 km for the period 1979‒2019 (WRF9km). Precipitation values from WRF9km and ERA5 were evaluated against satellite observations; compared with ERA5, WRF9km captured the climatological summer precipitation over the NWTP with a much-reduced wet bias. The ERA5 overestimation is mainly caused by excessive convective precipitation, likely linked to strong vertical motions over the NWTP induced by an overestimated lower-level southerly wind. [ABSTRACT FROM AUTHOR]

This study evaluates historical simulation of solar photovoltaic potential (PVpot) during 1989–2008 over China against the ERA5 reanalysis, using the Weather Research and Forecasting (WRF) model and Regional Climate Model version 4 (RegCM4) within the framework of the Coordinated Regional Downscaling Experiment-East Asia second phase (CORDEX-EA-II). The impacts of spectral nudging technique and land surface model on the simulated PVpot are investigated as well. Results indicate that the observed PVpot is abundant over western China, which can reach up to 26% in summer particularly. The WRF simulations significantly overestimate the PVpot over most areas of China, with the bias about 9% over southeastern China, while the utilization of spectral nudging method and CLM4 land surface model can greatly reduce the deviation. The RegCM4 simulations generate underestimation of PVpot over Northwest China and overestimation over Southeast China. As for the interannual variation, the observed PVpot features an increase of 0.9%/decade over southeastern China. The WRF and RegCM4 simulations can reproduce the rising trend of PVpot, while the magnitude is much lower than ERA5. The WRF simulations can properly portray the characteristics of seasonal cycle of PVpot, with the peaks in May over entire China and most subregions, while RegCM4 exhibits poor skill in reproducing the intra-annual variation. Moreover, the simulated bias in the clear-sky solar radiation (RSDSCS), low-level cloud fraction, and light rain during the daylight may contribute to the deficiency of PVpot. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) is an important component of the global climate system, while the characteristics of its climate are poorly represented in most regional climate models at coarse resolutions. In this study, a 20-year (2000–2019) dynamical downscaling simulation at the gray-zone resolution (9 km) using the WRF model driven by the ERA5 reanalysis is conducted over the TP. Based on comparisons against in-situ observations and the Integrated Multi-satellite Retrievals for GPM (IMERG) version 6 satellite precipitation product, the assessment of basic climate variables, such as near-surface air temperature (T2m) and precipitation, is performed to evaluate the model's performance and understand its added value better. Results show that both WRF and ERA5 can successfully reproduce the spatial patterns of annual mean and seasonal mean surface air temperature. However, significant cold and wet biases are found especially over the southeastern TP in ERA5, which are greatly improved in WRF with reduced RMSEs. Not only the climatological characteristics, but also the inter-annual variability and seasonal variation of T2m and precipitation are well captured by WRF which reduces the cold and wet biases especially in winter and summer compared to ERA5, respectively. Besides, at daily scale, the overestimation of precipitation in WRF and ERA5 is mainly caused by the overestimated precipitation frequency when precipitation intensity changed slightly. Furthermore, WRF outperforms ERA5 in capturing the diurnal variation of precipitation with more realistic peak time in all sub-regions over the TP. Further investigation into the mechanism of model bias reveals that less simulated snow cover fraction plays a crucial role in increasing the surface net energy by affecting surface albedo over the southeastern TP in WRF, leading to higher T2m. In addition, less water vapor transport from the southern boundary of TP leads to reduced wet bias in WRF, indicating that the added value in dynamical downscaling at gray-zone resolution is obtained by representing water vapor transport more realistically. [ABSTRACT FROM AUTHOR]

To identify potential predictors by assessing adverse outcomes in ANCA-associated vasculitis (AAV) patients. Eighty-nine untreated AAV patients were followed up to January 31, 2022, death, or loss of follow-up. Clinical characteristics, laboratory tests, treatment, and progress were collected, and disease activity was evaluated via Birmingham Vasculitis Activity Score (BVAS). We determined risk factors of high-risk events, defined as developing tumors, renal replacement therapy (RRT), and death. Patients and renal survivals were computed by the Kaplan–Meier curve analysis. Cox regression analysis was performed for assessing variables for predicting death. During 267 person-years follow-up, 46 patients occurred high-risk events, including 20 patients receiving RRT, 12 patients developing tumors, and 29 patients who died mostly from organ failure and infection. Decreased estimated glomerular filtration rate (eGFR) (P < 0.001) and complement 3 levels (P = 0.019) were associated with high-risk events. Patients with lower serum potassium tended to develop tumors (P = 0.033); with higher BVAS (HR = 1.290, 95%CI 1.075–1.549, P = 0.006) and lower eGFR (HR = 0.782, 95%CI 0.680–0.901, P = 0.001) were more likely to undergo RRT. Patients with cardio and renal involvement exhibited a lower frequency of renal survival and all-cause mortality. Through multivariate COX analysis, age (HR = 1.016, 95%CI 1.016–1.105, P = 0.006) and eGFR (HR = 0.982, 95%CI 0.968–0.997, P = 0.018) predicted death in AAV, separately. The BVAS and eGFR could be a great prognosticator for RRT, while age and eGFR can independently predict the death. Serum potassium level and immunoglobulins should be focused on their predictor value in development of cancer and renal outcomes in AAV patients. [ABSTRACT FROM AUTHOR]

Near-surface meteorological forcing (NSMF) datasets, mixed observations, and model forecasts are widely used in global climate change and sustainable development studies. For practical purposes, it is important to evaluate NSMF datasets, especially those released latest, and determine their strengths and limitations. In this study, we evaluate the performance of Multi-Source Weather (MSWX) in China over the period of 1979–2016. For comparison, ECMWF Reanalysis version 5 (ERA5), China Meteorological Forcing Dataset (CMFD) and Princeton Global Forcing (PGF) dataset are also evaluated to determine the strengths and weaknesses of MSWX. The following variables are compared with observations over 2400 stations: 2 m air temperature (T2m), 2 m daily maximum air temperature (Tmax), 2 m daily minimum air temperature (Tmin), precipitation (P), and 10 m wind speed (V10). The evaluation is conducted in terms of climatology, inter-annual variations and seasonal cycles. Results show that MSWX reasonably reproduces the spatial pattern of T2m with root-mean-square errors (RMSEs) below 1.12 °C and spatial correlations above 0.97, but underestimates Tmax and overestimates Tmin, with biases ranging from −2.0 °C to 2.0 °C, especially over the North China and Northeast China. Compared with ERA5 and PGF, MSWX can better simulate the inter-annual variations of surface air temperature with high spatial correlations (>0.97) but shows higher RMSEs than PGF. For precipitation, MSWX accurately captures the primary features of precipitation, including significant characteristics or patterns of the precipitation climatology and inter-annual variation. Its inter-annual variation shows low RMSEs ranging from 0.55 mm/day to 0.8 mm/day, compared to ERA5 and PGF. However, regions with abundant precipitation exhibit higher biases. Because the biased Global Wind Atlas (GWA3.1) is used for the wind bias correction of MSWX, MSWX significantly overestimates the annual mean wind speed, but it is consistently well-correlated with observations, with RMSEs less than 1.5 m/s and spatial correlations greater than 0.6 over the period of 1979–2016. This study reveals both the advantages and disadvantages of MSWX, and indicates the need for research into climate change and sustainable development in East Asia. [ABSTRACT FROM AUTHOR]

A wind gust parameterization scheme combined with the Weather Research and Forecasting (WRF) model used as the regional climate model (RCM) is employed to simulate and project the gust wind speed at 10‐m height above ground level for the whole China in the historical and future period 1981–2005 and 2036–2060. The gust wind speed is compared between the historical and future period to investigate its long‐term change under the background of warming climate within the CORDEX‐EA‐II project under the RCP8.5 scenario. First, the gust wind speed simulated by the gust parameterization inputted with the RCM simulations driven by the ERA‐Interim reanalysis data is compared with the ERA5 reanalysis data and their discrepancy is discussed. Then the historical/future gust wind speed is simulated/projected with the RCM simulations driven by four global climate models' results. The comparisons between the historical simulations and future projections show the gust wind speeds overall change slightly with little response to the future warming climate as the whole China is concerned, and the maximal increment and decrement of averaged annual maximal gust wind speed are, respectively, 2.25 and −2.57 m·s−1. The increases greater than 1 m·s−1 are mostly located in the eastern and southeastern coast and northwestern inland while the decreases less than −1 m·s−1 are mostly located in part of the Tibet Plateau and northwestern inland. [ABSTRACT FROM AUTHOR]

Compound hazards are more destructive than the individual ones. Using observational and reanalysis datasets during 1960–2019, this study shows a remarkable concurrent relationship between extreme heatwaves (HWs) over southeastern coast of China (SECC) and tropical cyclone (TC) activities over western North Pacific (WNP). Overall, 70% of HWs co-occurred with TC activities (TC–HWs) in the past 60 years. Although the total frequency of TCs over WNP exhibited a decreasing trend, the occurrences of TC–HWs over SECC have been increasing, primarily due to the increasing HWs in the warming climate. In addition, TC–HWs are stronger and longer lasting than HWs that occur alone (AHWs). And in the long-term perspective, both AHWs and TC–HWs exhibit increasing trends, especially since the mid-1980s. The enhancement on HWs caused by TC activities is sustained until TCs make their landfalls and then collapse. Based on composite analysis, TC activities enhance HWs by modulating atmospheric circulations and triggering anomalous descending motion over southern China mainland which intensifies the western Pacific subtropical high (WPSH) and favors increased temperatures therein. Given the severe adverse impacts of TC–HWs on coastal populations, more research is needed to assess the future projections of TC–HWs, as HWs are expected to be more frequent and stronger as the climate warms, whereas TCs over WNP may occur less often. [ABSTRACT FROM AUTHOR]

Driven by ERA‐Interim reanalysis, two climate simulations are conducted from April to August for 20 years (1998–2017) during the East Asia summer monsoon with Model for Prediction Across Scale‐Atmosphere (MPAS‐A). The global variable‐resolution (MPAS‐VR) and regional (MPAS‐RCM) configurations are adopted under the same model framework with 92–25 km mesh refinement centered over Mainland China (MPAS‐A experiments hereafter). MPAS‐VR allows flexible interactions across scales. Constrained by the "reanalysis‐based" lateral boundary conditions (LBCs), MPAS‐RCM could well capture the evolution of large‐scale fields and becomes a proper reference for evaluating MPAS‐VR. The evaluations are conducted for precipitation, near‐surface air temperature, and circulation features against observed climate. Two MPAS‐A experiments present comparable results for the mean climatology and interannual variability except that MPAS‐VR presents wet biases along the tropical ocean and underestimation in the Yangtze–Huaihe River basin. Compared with MPAS‐VR, MPAS‐RCM presents better daily variations and rain belts' evolution, which demonstrates the crucial effects of the LBCs for the limited‐area model. The simulated circulation and moisture flux can explain most of the deviations. However, two MPAS‐A experiments show consistent results for the extreme precipitation frequency and the extreme indices over Mainland China. With the same dynamic core and model physics, those climate features are similarly resolved by the two simulations. Thus, the 92–25 km MPAS‐VR simulation is demonstrated as a promising tool for regional climate hindcast. Plain Language Summary: In this work, we conduct model experiments by two configurations during the East Asia summer monsoon using Model for Prediction Across Scale‐Atmosphere with refinement mesh centered over Mainland China. The global variable‐resolution configuration (MPAS‐VR hereafter) allows flexible interaction across global features to regional climate details. Constrained by the reanalysis (which blends simulated and observed results) around the boundary, the regional limited‐area configuration with the truncated mesh (MPAS‐RCM hereafter) is used for identifying the model's biases mostly related to its dynamic core and parameterization, which is a proper reference for MPAS‐VR. We evaluate the model's performances against the observed climate for the near‐surface air temperature and precipitation. Using MPAS‐RCM as the criterion, MPAS‐VR well captures the mean climatology, interannual variability, and extreme events, which demonstrates itself as a promising tool for regional climate details. The diverged circulation in the two experiments can explain most of the simulated biases. Extreme precipitation frequency and extreme indices over Mainland China suggest similar deficiencies in the two simulations due to a common model framework. Key Points: Dynamical downscaling is conducted by Model for Prediction Across Scale for Atmosphere (MPAS‐A) with a global variable‐resolution (MPAS‐VR) and truncated regional (MPAS‐RCM) configurationsTwo MPAS‐A experiments present comparable results with simulated circulation explaining most of their divergencesExtreme frequency and indices over Mainland China suggest similar deficiencies in the two simulations due to a common model framework [ABSTRACT FROM AUTHOR]

Persistent hot and dry conditions could lead to serious impacts on society, economy, and human health. Using statistically downscaled and bias corrected data, we investigate the changes in compound long‐duration dry and hot (LDDH) events and the corresponding socioeconomic exposure over China in transient and stabilized warmer worlds. The transient response is identified with Coupled Model Intercomparison Project Phase 5 (CMIP5) and CMIP6 models, while the stabilized response is identified with the Community Earth System Model ensemble. Under 1.5°C and 2°C warming, the LDDH events in China will become more frequent and hotter. Substantial differences are found in LDDH features between transient and stabilized warming. For a given global temperature, the increase in frequency and temperature magnitude of LDDH events over most northern regions is significantly greater in a transient case than in a stabilized climate, while the increase over the southeastern China is substantially stronger under stabilized warming than transient warming. Future population exposure to LDDH events is projected to increase over China. For many regions, the aggregate exposure is two times greater in a transient climate than in a stabilized climate. Under transient warming, changes in LDDH events dominate the increase in population exposure whereas population change has smaller effects below 10%. For a stabilized warmer world, the negative population growth can largely offset the impact of climate change on exposure. Limiting global warming to 1.5°C instead of 2°C can reduce the exposure to LDDH events by 26.1% and 21.8% over China under transient and stabilized warming, respectively. Key Points: Compound events are more frequent and hotter over much of the northern regions in a transient world than the stabilized onePopulation exposure in a transient climate is 1.5–2.3 times higher than that in a stabilized climateThe increased exposure is driven by climate change alone (changes in climate and population) in a transient (stabilized) world [ABSTRACT FROM AUTHOR]

Using fourteen global climate models (GCMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5) downscaled by four statistical downscaling methods, future changes and the associated uncertainty in concurrent long-duration dry and hot (LDDH) events are investigated in China during summer. The downscaling methods include BCSD (bias-correction and spatial downscaling), BCCI (bias-correction and climate imprint), BCCAQ (bias correction constructed analogues with quantile mapping reordering), and CDF-t (cumulative distribution function transform). The downscaling methods can efficiently improve the accuracy over the driving GCMs in terms of spatial variability, bias, and inter-annual variability of LDDH characteristics. Overall, the three quantile mapping based techniques (BCSD, BCCI, and BCCAQ) outperform CDF-t in simulating the spatial and temporal features of LDDH events. In the twenty-first century, all downscaling methods project a consistent increasing tendency for the frequency, magnitude, and total days of LDDH events over most parts of China, with higher increases under RCP8.5 compared to RCP4.5. A substantial increase in spatially contiguous regions simultaneously experiencing LDDH events is seen by mid-century under both scenarios. Changes in the frequency, magnitude, and total days of LDDH events are predicted with high confidence. For most indices, model uncertainty dominates throughout the century and does not change much over time. However, for the projection of temperature magnitude of LDDH events, the dominant role of GCM related uncertainty in the early twenty-first century declines as scenario uncertainty becomes more important towards the end of the century. [ABSTRACT FROM AUTHOR]

Compound dry and hot events can cause aggregated damage compared with isolated hazards. Although increasing attention has been paid to compound dry and hot events, the persistence of such hazards is rarely investigated. Moreover, little attention has been paid to the simultaneous evolution process of such hazards in space and time. Based on observations during 1961–2014, the spatiotemporal characteristics of compound long-duration dry and hot (LDDH) events in China during the summer season are investigated on both a grid basis and a 3D event basis. Grid-scale LDDH events mainly occur in eastern China, especially over northeastern areas. Most regions have experienced a pronounced increase in the likelihood of LDDH events, which is dominated by increasing temperatures. From a 3D perspective, 146 spatiotemporal LDDH (SLDDH) events are detected and grouped into 9 spatial patterns. Over time, there is a significant increase in the frequency and spatial extent of SLDDH events. Consistent with the grid-scale LDDH events, hotspots of SLDDH events mainly occur in northern China, such as the Northeast China, North China and Qinghai clusters, which are accompanied by a high occurrence frequency and large affected areas greater than 300 000 km 2. [ABSTRACT FROM AUTHOR]

The Weather Research and Forecasting (WRF) model was applied to simulate the current and future climates over eastern China at a convection‐permitting resolution (∼4 km). A continuous 10‐year (1998–2007) simulation was performed for the historical climate, and three pseudo‐global warming (PGW) experiments driven by climate perturbations during 2070–2099 were conducted under the RCP2.6, RCP4.5, and RCP8.5 scenarios. After validation against reanalysis and observational data, the historical simulation was found capable of reasonably reproducing the characteristics of mean precipitation, extreme hourly precipitation, and large‐scale circulation. The PGW experiments projected an increase in precipitation intensity over most regions, especially North China under the RCP8.5 scenario (up to 30%). However, the precipitation frequency was projected to decrease, especially over the Yangtze River Basin in summer. A wetting (drying) trend was observed over North China (South China) in summer (winter), due to the increase (decrease) in precipitation intensity (frequency). The intensity and frequency of extreme events were projected to increase over most areas of eastern China, and the increase was the most dramatic under the RCP8.5 scenario, indicating a greater flood risk under stronger global warming. The relationship between extreme precipitation and temperature (EP–T) displayed a hook‐shape structure in both the present and future climates. The extreme precipitation intensity increased with temperature at a super Clausius–Clapeyron (C–C) scaling rate (>7%/K) until reaching a peak at temperatures of around 25–29°C, and then decreased at higher temperatures. The decreases were mainly attributed to moisture limitation at high temperatures. In the future, the EP–T relationship is expected to change mostly following the C–C law, with greater precipitation peaks under scenarios with higher carbon emissions, indicating that warmer climates contribute to further enhancement of extreme precipitation. Plain Language Summary: The extreme precipitation–temperature (EP–T) scaling relation is a useful conceptual tool for understanding the changes in extreme precipitation in present and future climates. EP‐T relation is related to Clausius–Clapeyron (C–C) relationship which indicates that precipitation is expected to increase by 7% for each degree of temperature increasing. However, EP‐T relation can deviate from the C–C scaling according to studies based on observations and numerical models. The relation between hourly EP and T is essential for predicting instantaneous weather hazards over eastern China, but such relation was not well reproduced by previous studies using GCMs with coarser resolution. In this study, we investigated the current and future hourly EP–T relation over eastern China using high‐resolution (4 km) convection‐permitting RCM (CP‐RCM). Our analysis indicates that CP‐RCM can well reproduce the characteristics of extreme hourly precipitation and large‐scale circulation. Precipitation intensity will increase but precipitation frequency will decrease in the future over eastern China. The EP–T relation displays a hook‐shape structure in both the present and future climates mainly due to moisture limitation at higher temperatures. The warmer the future climates, the more intense the extreme precipitation. Key Points: Future changes in precipitation over eastern China were assessed using pseudo‐global warming simulations at a convective‐permitting resolutionHourly extreme precipitation was projected to be more frequent and intense over eastern China in the future, while light and moderate rain will likely decreaseHourly extreme precipitation and temperature over eastern China displayed a hook‐shape relationship, due to moisture limitation at high temperatures [ABSTRACT FROM AUTHOR]

Objective: To identify primary Sjögren’s syndrome (pSS) patients with arthralgia at risk for osteoarthritis (OA) or arthritis. Methods: This study included 368 pSS patients admitted to a mono-centric from March 2010 to December 2020. Patients were divided into groups according to whether complicated with OA or arthritis. Data were analyzed to determine the differences in demographical characteristics, symptoms, and laboratory examination. Results: The involvement of the OA joints was predominately knee and spine sites (including cervical and lumbar spine degeneration). When diagnosing arthritis, it was mainly peripheral symmetric polyarthritis, the most affected sites were the interphalangeal and metacarpophalangeal joints. There were significant differences in age, disease duration, uric acid (UA), and total cholesterol (TC) between pSS-OA and pSS-nOA patients (P < 0.050). Logistic regression analysis showed that age (OR = 1.965; P = 0.009) and joint pain (OR = 3.382; P < 0.001) were dangerous factors associated with OA. Interestingly, although the level of UA, TC, and triglycerides (TG) was shown to be positive with OA, there was no statistical significance after the OR was computed in the four-cell table. In pSS-arthritis, EULAR Sjögren's syndrome disease activity index (ESSDAI) (P = 0.011), the frequency of joint pain (P < 0.001), and muscular involvement (P = 0.037) were higher than non-arthritis group. In pSS patients only presenting with joint pain, arthritis patients had higher ESSDAI and system involvements, but lower UA and TG levels compared with OA group (P < 0.050). Conclusion: In pSS patients with arthralgia, OA accounted for the majority. pSS patients with advanced age and more pronounced metabolic characteristics, such as elevated blood lipids and uric acid, was a key factor in groups at risk for OA. However, arthritis patients had higher rates of dry mouth and eye, higher disease activity, antibodies positive, and more organs damage. In the future, it may be necessary to be more cautious in the diagnosis of joint manifestations in pSS patients in order to make the appropriate treatments. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) is often referred to as 'the Third Pole' and plays an essential role in the global climate. However, it remains challenging for most global and regional models to realistically simulate the characteristics of climate over the TP. In this study, two Weather Research and Forecasting model (WRF) experiments using spectral nudging with gray-zone (GZ9) and convection-permitting (CP3) resolution are conducted for summers from 2009 to 2018. The surface air temperature (T2m) and precipitation from the two simulations and the global reanalysis ERA5 are evaluated against in-situ observations. The results show that ERA5 has a general cold bias over southern TP, especially in maximum T2m (Tmax), and wet bias over whole TP. Both experiments can successfully capture the spatial pattern and daily variation of T2m and precipitation, though cold bias for temperature and dry bias for precipitation exist especially over the regions south of 35° N. Compared with ERA5, the added value of the two WRF experiments is mainly reflected in the reduced cold bias especially for Tmax with more improvement found in CP3 and the reduced wet bias. However, the ability of the convection-permitting WRF experiment in improving the simulation of precipitation seems limited when compared to the gray-zone WRF experiment, which may be related to the biases in physical parameterization and lack of representativeness of station observation. Further investigation into surface radiation budget reveals that the underestimation of net shortwave radiation contributes a lot to the cold bias of T2m over the southeastern TP in GZ9 which is improved in CP3. Compared with GZ9, CP3 shows that larger specific humidity at low-level (mid-high level) coexists with more precipitation (clouds) over the southern TP. This improvement is achieved by better depiction of topographic details, underlying surface and atmospheric processes, land–atmosphere interactions and so on, leading to stronger northward water vapor transport (WVT) in CP3, providing more water vapor for precipitation at surface and much wetter condition in the mid-high level. [ABSTRACT FROM AUTHOR]

In an actual thermal power plant, deep peak shaving will cause thermal power units to run under non-nominal conditions for an extended period, resulting in serious problems such as increased equipment wearing, low equipment utilization efficiency and decreased benefits. To this end, in this work, both the design and optimization method for a coal to hydrogen system which is coupled with the expected non-nominal operation of thermal power units are proposed. Aiming towards maximum profit in the context of thermal power plants, a mathematical optimization model for a coal to hydrogen system based on the multi-period operating conditions of thermal power plants is established. The corresponding optimal design scheme of the coal to hydrogen system is determined using variable operating conditions. The superiority of the integrated system compared with an independent system is explored and the feasibility of the proposed method is verified by using the case study of an actual thermal power plant. The results show that compared with the independent system, the economic benefits of the integrated system can increase by 13.56%, where the sale of hydrogen in the coal to hydrogen system accounts for 60.3% of the total benefit. The main expenditure associated with the system is the purchase cost of feedstock coal, accounting for 91.8%. Since the required power and medium-pressure steam in the coal to hydrogen process are provided by thermal power units, the minimum operating load of the thermal power plant in the integrated system increases from 40% to 60.1%, which significantly improves the utilization efficiency and service life of the generator units. In addition, the proposed integration scheme of the system is simple and controllable, which can contribute to the maintenance of the safe and stable operation of power generation and hydrogen production processes. These results are expected to provide the necessary methodological guidance for the integration and optimization of coal-fired power plants and coal to hydrogen systems. [ABSTRACT FROM AUTHOR]

Driven by the outputs of four global climate models from Coupled Model Intercomparison Project Phase 5, a long-term downscaling and projection under the RCP8.5 scenario is conducted within the Coordinated Regional Downscaling Experiment East Asia phase II framework with Weather Research and Forecasting Model (WRF) and Regional Climate Model version 4 (RegCM4). All the single simulations and the ensembles well reproduce the spatial pattern of the precipitation amount over East Asia with the spatial correlations (SCORs) larger than 0.58, although bias exists in some areas. The models also reasonably present the spatial patterns of the extreme precipitation indices except the Rx5day (annual maximum consecutive 5-day precipitation) and the consecutive dry days (CDD), with the SCORs ranging between 0.43 and 0.71. In general, WRF outperforms RegCM4 in producing the spatial patterns of most extreme precipitation indices and RegCM4 generates lower root mean square errors. In the future, the precipitation amount would significantly increase in northeastern China and northwestern China and over the Tibetan Plateau, which is mainly due to the increase of precipitation intensity in WRF and frequency in RegCM4. The extreme frequency and intensity indices are projected to significantly increase over the Tibetan Plateau and some areas of northwestern China. In addition, the consecutive wet days will get significantly longer in the above regions, where the consecutive dry days will shorten, indicating more consecutive precipitation events in the future. The change in the probability distribution of the extreme indices reveals that stronger and longer-duration extreme precipitation events would get more frequent in the future. The increase of low-level specific humidity can partly explain the increase of precipitation. [ABSTRACT FROM AUTHOR]

Within the frameworks of the Coordinated Regional Downscaling Experiment‐East Asia first and second phase (CORDEX‐EA‐I and CORDEX‐EA‐II), the impact of spatial resolution, physical parameterization schemes and spectral nudging (SN) on simulating inland and offshore near‐surface wind speed over China is evaluated. By using WRF and RegCM4 models, the CORDEX‐EA simulations driven by the ERA‐Interim reanalysis data are conducted from 1989 to 2008. The regional climate models (RCMs) have the capacity to simulate the spatial patterns of surface wind, although significant overestimations exist over inland China. The WRF CORDEX‐EA‐II experiments with increasing horizontal resolution perform better in reproducing both inland and offshore wind speed than the CORDEX‐EA‐I experiments. Moreover, the experiments with SN can significantly reduce the positive biases of surface wind speed. For the temporal variation of wind speed, almost all the simulations show larger biases in winter than in summer. Particularly, the simulated wind speed in summer in the RegCM4 experiment with CLM3 land surface model (RCC‐II) is close to the observations. The extreme wind speed can be well reproduced by WRF simulations, and the SN experiments perform better than the experiments without SN (NOSN). In addition, the overestimations of surface wind speed can be partly explained by the overestimations of the wind field at 850 hPa level inherited from ERA‐Interim reanalysis and the increase of temperature gradient between the land and ocean in winter. [ABSTRACT FROM AUTHOR]

Under the Coordinated Regional Downscaling Experiment‐East Asia second phase (CORDEX‐EA‐II) framework, the performances of three regional climate models (RCMs), including Weather Research and Forecasting (WRF) model, RegCM4 and Consortium for Small‐Scale Modelling model in Climate Mode (CCLM), in simulating the climatic distribution, diurnal variation and extremes of precipitation during 1989–2009 are evaluated. The RCMs are driven by the ERA‐Interim reanalysis and the evaluation is based on both the gridded gauge‐based and the satellite‐derived precipitation data. In general, the RCMs can reproduce the spatial pattern of the mean daily precipitation, with the spatial correlations (SCORs) larger than 0.66, and CCLM has the lowest root‐mean‐square error over East Asia. For the diurnal cycle of precipitation, WRF outperforms the other two RCMs despite the peak time about 3 hr ahead in some areas. RegCM4 overestimates the amplitude of the diurnal curve, and CCLM has limited ability to simulate the diurnal variation over most areas. All the three RCMs can reproduce the spatial patterns of the extreme indices, with the SCORs larger than 0.57. WRF and CCLM perform the best for the frequency of wet days (R1mm) and moderate rain (R20mm), respectively. The intensity indices are overestimated over most land areas, with relatively higher SCORs in WRF and relatively lower biases in RegCM4. The consecutive wet days (CWD) can be well simulated by WRF and CCLM; however, RegCM4 overestimates it over most regions in East Asia. The overestimation of the extreme intensity and frequency indices may be related to the higher water vapour content and the weaker water vapour divergence in the lower layer, as well as the higher mid‐layer geopotential height, especially in CCLM. [ABSTRACT FROM AUTHOR]

The multidimensional regulation of the directional transport of bubbles is of great importance in the field of subsea gas extraction, with the increased complexity of controlling the direction of underwater bubble transport making it more challenging. Herein, drawing on a variety of bionic technologies, nanosecond laser processing combined with a low surface energy reagent modification to prepare porous hydrophobic/superhydrophobic Janus tapered aluminum foil (JTAF) is used. The wettability gradient of JTAF promotes unidirectionally self‐driven penetration of bubbles, and the shape gradient facilitates self‐driven transport of bubbles from the tip to the root. The synergistic effect of the two gradient forces endows bubbles with unidirectional self‐driven transport capability in both the buoyancy direction and the antibuoyancy direction. Finally, the JTAFs are used as bipolar electrodes in electrolysis cells to achieve gas generation, self‐driven transport, and collection processes by electrolyzing saturated saltwater. This simple, low‐cost, controlled approach to laser processing of the JTAF has tremendous potential for underwater self‐driven gas transport and is a promising tool for solving energy and environmental problems. [ABSTRACT FROM AUTHOR]

This paper addresses an effective method for the selection and design of optimal working fluids of organic Rankine cycle (ORC) based on quantitative working fluid selection rules, aiming to reduce the complexity and improve the calculation efficiency of the working fluid design model. In the proposed method, the critical properties of the optimal working fluids for the given heat sources are first explored and summarized based on the quantitative relationship obtained by existing research and simulations. Based on the concept of working fluid substitution, the critical properties of the optimal pure working fluid are then adopted to target the optimal mixture working fluid by solving a modified computer-aided molecular-mixture design (CAMD) model and the ratio r of critical pressure to critical temperature is also strictly constrained to ensure a better working fluid. The component and the composition of the mixture working fluid are, thus, determined simultaneously. Results showed that both the designed pure and mixture working fluids have better performance than the existing ones determined by the selection and design rules. The targeted mixture working fluid enables one to achieve at least similar systematic efficiency and a better exergy efficiency in ORC than pure working fluid featuring similar critical properties. The application of the proposed method and model is finally verified via a practical case study. [ABSTRACT FROM AUTHOR]

Background. Multiple system and organ damage occurs with the continuous progression of primary Sjögren's syndrome (pSS), and the lack of specific drugs against this disease is a huge challenge. White peony (WP), a widely used traditional Chinese herb, has been confirmed to have a therapeutic value in pSS. However, the specific mechanisms of WP in the treatment of pSS are unknown. Methods. The active ingredients and their targets in WP were searched on the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), and disease-related targets were collected from GeneCards, Online Mendelian Inheritance in Man (OMIM), and the Therapeutic Target Database (TTD). The overlapping targets were acquired by taking the intersection. A protein-protein interaction (PPI) network was structured using the STRING database. A disease-drug-ingredient-target (D-D-I-T) network was built using Cytoscape software. By filtering twice, core targets were acquired. Gene Ontology (GO) and Kyoto Encyclopedia Gene and Genome (KEGG) pathway enrichment analysis were accompanied by R packages. Finally, molecular docking was used to verify the abovementioned results. Results. In total, we screened 88 WP-related targets, 1480 pSS-related targets, and 32 overlapping targets. D-D-I-T Network analysis displayed six main active ingredients of WP, which played a significant therapeutic role in pSS. Further topological analysis selected seven core target genes, including IL-6, TNF, PPARγ, AKT1, CASP3, NOS3, and JUN. GO and KEGG analysis were used to elucidate pharmacological mechanisms, mainly acting in the AGE-RAGE signaling pathway. Molecular docking proved that paeoniflorin bound well with core targets. Conclusion. Our study revealed that IL-6, TNF, AKT1, CASP3, NOS3, and JUN may be pathogenic target genes, and PPARγ may be a protective target gene. The main active ingredients of WP mainly played a therapeutic role via the AGE-RAGE signaling pathway. These findings provide a fundamental and theoretical basis for the clinical application of WP. [ABSTRACT FROM AUTHOR]

To study the effects of aluminum alloys processed by a laser in air and water and at different water velocities, corresponding experiments were conducted and the impacting effects of different water velocities on the surface of the workpiece were simulated, respectively. The results show that when laser processing aluminum alloy materials in air, there is more slag and a recondensation layer on both sides of the groove, the heat-affected zone is larger and the surface processing quality is poor. When laser processing aluminum alloy materials in water, the processing quality is improved. With the increase in water velocity, the impacting and cooling effect is enhanced, the groove depth and groove width show a trend of first increasing and then decreasing, the slag and recondensation layer on both sides of the groove are reduced, the heat-affected zone is reduced and the processing quality of the groove is improved. When the water velocity reaches 30 m/s, a better groove can be obtained. Laser processing aluminum alloy materials in water can obtain better processing quality than laser processing in air. [ABSTRACT FROM AUTHOR]

This study analyzes the spatial and temporal distribution characteristics of the in situ aircraft observations in the middle and higher troposphere in 2019. These aircraft observations are mainly distributed in China, and relatively evenly recorded between 0000 and 1500 UTC in time and 6 and 10 km in height. Based on the 3395 stronger clear-air turbulence (CAT) events and 4038 weaker CAT events selected from the observations in the study region (15°–55°N, 70°–140°E), the performances of 24 CAT diagnostics calculated from the ERA5 data are evaluated. Results show that the diagnostics connected with vertical wind shear (i.e., version 1 of the North Carolina State University index, negative Richardson number, variant 3 and variant 1 of Ellrod's turbulence index) have the best performances. However, the performances vary greatly from season to season, and overall performances are the best in winter and worst in summer. The annual and seasonal best thresholds for these diagnostics are also listed in this study. [ABSTRACT FROM AUTHOR]

Introduction: Atopic dermatitis (AD) is a chronic, pruritic, inflammatory skin disease with rising prevalence. Topical corticosteroids (TCS) are recommended as first-line therapy for patients with AD in China; however, corticophobia is a widespread concern, which can manifest as noncompliance: in a previous Chinese study, almost all parents whose children had AD were very concerned about the side effects of TCS and, as a result, nearly half did not use it in the event of recurrence. We propose a TCS-sparing treatment algorithm for the management of infants, children, adolescents, and adults with mild-to-moderate AD, to guide clinical practice in China. Methods: A panel of eight experts in AD from China and one expert from Germany formed to develop a practical algorithm for the management of mild-to-moderate AD, focusing on pimecrolimus. Results: Irrespective of body location, all patients with mild AD (including acute flares) and infants with moderate AD should apply the topical calcineurin inhibitor (TCI) pimecrolimus twice daily to the affected area until symptoms disappear. For children, adolescents, and adults with moderate AD, pimecrolimus should be applied twice daily to sensitive skin areas, and a TCI (either pimecrolimus or tacrolimus) should be applied twice daily to other body locations. Short-term administration of TCS, followed by TCI twice daily, is recommended for most patients with moderate AD experiencing acute flares, regardless of lesion site. Emollients should be used regularly. Conclusions: The algorithm presented intends to simplify treatment of AD in China and guide clinical decision-making. [ABSTRACT FROM AUTHOR]

A large population in China has been exposed to both severe ozone (O 3) pollution and extreme heat under global warming. Here, the spatiotemporal characteristics of coupled extremes in surface O 3 and heat (OPCs) over China are investigated using surface observations, a process-based chemical transport model (GEOS-Chem), and multi-model simulations from Phase 6 of the Coupled Model Intercomparison Project (CMIP6). North China Plain (NCP; 37–41 ∘ N; 114–120 ∘ E) is identified as a hot spot of OPCs, where more than half of the O 3 pollution days are accompanied by high temperature extremes. OPCs over NCP exceeded 40 d during 2014–2019, exhibiting an increasing trend. Both O 3 concentrations and temperatures are elevated during OPCs compared with O 3 pollution days occurring individually (OPIs). Therefore, OPCs impose more severe health impacts to humans than OPIs, but the stronger health effects are mainly driven by the higher temperatures. GEOS-Chem simulations further reveal that enhanced chemical production resulting from hot and stable atmospheric conditions under anomalous weather patterns primarily contributes to the exacerbated O 3 levels during OPCs. In the future, CMIP6 projections suggest increased occurrences of OPCs over NCP in the middle of this century, but by the end of this century, OPCs may decrease or increase depending on the pollutant emission scenarios. However, for all future scenarios, extreme high temperatures will play an increasingly important role in modulating O 3 pollution in a warming climate. [ABSTRACT FROM AUTHOR]

Two regional climate simulation experiments (spectral nudging and re-initialization) at convection-permitting scale are conducted using the WRF model driven by the 4th generation Global Reanalysis data (ERA5) from European Centre for Medium-Range Weather Forecasts over the Tibetan Plateau (TP). The surface air temperature (T2m) and the precipitation in summer during 2016–2018 are evaluated against the in-situ station observations and the Global Satellite Mapping of Precipitation (GSMaP) dataset. The results show that both experiments as well as ERA5 can successfully capture the spatial distribution and the daily variation of T2m and precipitation, with reasonable cold bias for temperature and dry bias for precipitation when compared with the station observations. In addition, the diurnal cycle of precipitation is investigated, indicating that both experiments tend to simulate the afternoon precipitation peak in advance and postpone the night precipitation peak. The precipitation bias is reduced by using the spectral nudging technique, especially at night and early morning. Both WRF experiments outperform ERA5 in reproducing the diurnal cycle of precipitation amount. Possible causes for the differences between the two experiments are also analyzed. In the re-initialization experiment, the daytime net shortwave radiation contributes a lot to the cold biases of Tmax, and the stronger vertically integrated moisture flux convergence leads to more precipitation compared with the spectral nudging experiment over the central and southeastern TP. These results can provide valuable guidance for further fine-scale simulation studies over the TP. [ABSTRACT FROM AUTHOR]

Dietary folate deficiency (FD) is associated with the occurrence of birth defects. However, the mechanisms underlying this association remain elusive. In particular, how FD affects genome stability is unknown. To examine whether a folate-deficient diet can affect genome stability, C57BL/6 mice were maintained on a synthetic diet lacking of folic acid (FA) for two generations. F0 mice received the FD diet beginning at 3 weeks of age, and their offspring (F1) began the FD diet after weaning. Both male and female F1 mice fed the FD diet were intentionally crossed with F1 mice fed the normal diet to produce F2 mice. F2 embryos were dissected and collected at E14.5 and E18.5. The malformation ratio was significantly increased in F2 embryos fed the FD diet for two generations compared to those fed the normal diet. Whole-genome sequencing of multiple sibship with F1 males on the FD diet showed that the de novo mutation (DNM) rate in F2 embryos was three times of the reported spontaneous rate in mice. Furthermore, many DNMs observed in the F2 mice exhibited an allele ratio of 1:3 instead of 2:2, suggesting that these mutations are likely to accumulate in gamete cells as a form of mismatch in the DNA duplex. Our study indicated that FD for two generations significantly enhances DNM accumulation during meiosis, which might contribute to the increased negative birth outcomes among F2 mice. Not only maternal but also paternal FA supplementation is probably also necessary and beneficial to prevent birth defects. [ABSTRACT FROM AUTHOR]

Dietary folate deficiency (FD) is associated with the occurrence of birth defects. However, the mechanisms underlying this association remain elusive. In particular, how FD affects genome stability is unknown. To examine whether a folate-deficient diet can affect genome stability, C57BL/6 mice were maintained on a synthetic diet lacking of folic acid (FA) for two generations. F0 mice received the FD diet beginning at 3 weeks of age, and their offspring (F1) began the FD diet after weaning. Both male and female F1 mice fed the FD diet were intentionally crossed with F1 mice fed the normal diet to produce F2 mice. F2 embryos were dissected and collected at E14.5 and E18.5. The malformation ratio was significantly increased in F2 embryos fed the FD diet for two generations compared to those fed the normal diet. Whole-genome sequencing of multiple sibship with F1 males on the FD diet showed that the de novo mutation (DNM) rate in F2 embryos was three times of the reported spontaneous rate in mice. Furthermore, many DNMs observed in the F2 mice exhibited an allele ratio of 1:3 instead of 2:2, suggesting that these mutations are likely to accumulate in gamete cells as a form of mismatch in the DNA duplex. Our study indicated that FD for two generations significantly enhances DNM accumulation during meiosis, which might contribute to the increased negative birth outcomes among F2 mice. Not only maternal but also paternal FA supplementation is probably also necessary and beneficial to prevent birth defects. [ABSTRACT FROM AUTHOR]