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The arid region of Northwest China (ARNC) has experienced a significantly higher warming rate than the global average and exhibits pronounced seasonal asymmetry, which has important implications for the region's water-dependent systems. To understand the spatiotemporal patterns and driving mechanisms of seasonal asymmetric warming in the ARNC, we investigated seasonal changes in temperature rise and their underlying causes based on station and reanalysis data. We found that the dominant season of temperature increase shifted from winter to spring. The contribution of spring warming to the total temperature increase rose from −5%–7% to 58%–59%, while the contribution of winter warming decreased from 60%–75% to −4%–9%. However, the mechanisms underlying spring warming and winter cooling differ. An increase in solar radiation caused by a decrease in cloud cover (R = −0.64) was the main reason for spring warming, while a strengthening Siberian High primarily drove winter cooling. [ABSTRACT FROM AUTHOR]

Climate prediction is of great significance to the prevention of drought and flood. "Ground-synoptic" map is a method for short-term climate prediction. The main content of this method is "Geothermal Vortex"(GV). Therefore, some characteristics of 3.2 m soil temperature anomaly (hereinafter abbreviated as T′ 3.2 m) and GV are analyzed by using the data of monthly soil temperature at the depth of 3.2 m from 1980 to 2017 in China. Results show that there are regional differences in the frequency of positive anomaly. Overall, there are more positive anomalies in southern China and fewer in Western China. Soil temperature anomaly has good memory, the shortest being 5 months and the longest being nearly 2 years. Moreover, results show the nonuniform distribution of memory duration and decreases from northwest to southeast as a whole. Statistical analysis of GV shows that the average life cycle of each GV is 9.7 months, with an average horizontal scale of 604 km and a characteristic scale of 2.4 cm/s. Spatially, the GV scale is largest in Northwest, with a horizontal scale of 1087 km, and the GV appear most frequently in North China. The central location of GV is uneven, mainly in the central area with strong crustal activity and large absolute vertical deformation rate or in the high value area of soil heat flow. [ABSTRACT FROM AUTHOR]

Except for conventional mesoscale eddies, there are also abundant warm cyclonic eddies (WCEs) and cold anticyclonic eddies (CAEs) in the global ocean. Based on the global mesoscale eddy trajectory atlas product, satellite altimetric and remote sensing datasets, and three-dimensional temperature/salinity dataset, spatiotemporal features of WCEs and CAEs are compared with traditional cold cyclonic eddies and warm anticyclonic eddies in the Kuroshio Extension (KE; 28°–43°N, 140°–170°E) region. Characteristics of abnormal eddies like radius, amplitude, eddy kinetic energy, and proportion in all eddies behave in significant asymmetry on the north and south sides of the KE jet. Unlike eddies in the general sense, temporal feature analysis reveals that it is more favorable to the formation and maintenance of WCEs and CAEs in summer and autumn, while winter is the opposite. The spatiotemporal variation of abnormal eddies is likely because the marine environment varying with time and space. Statistically, proportion of abnormal eddies increases rapidly in decaying stage during the whole eddy lifespan, resulting in smaller average radius, amplitude, sea surface temperature anomaly and sea surface height anomaly compared to normal ones. The three-dimensional composite structures for four types of eddies expose that the difference between abnormal and conventional eddies is not just limited to the sea surface, but also exists within the water below the sea surface. Vertical structures also indicate that the anomalous temperature signal is confined in the water from the sea surface to layers at about 30 m in the KE region. [ABSTRACT FROM AUTHOR]

Droughts and heat waves exhibit synergistic effects and are among the world's most costly disasters. To explore the spatiotemporal differences and formation mechanisms of the combined vulnerability to droughts and heat waves in Shandong Province over the past 20 years, a vulnerability scoping diagram (VSD) model with three dimensions—exposure, sensitivity, and adaptability—was constructed to assess and compare the combined vulnerability to high-temperature and drought events, considering economic and social conditions. The results showed that (1) over the past 20 years, heat waves and droughts have increased in Shandong Province. The number of high-temperature events significantly increased in the west and decreased along the eastern coast, and drought change was characterized by an increase in the south and a decrease in the north. (2) The combined exposure to summer droughts and heat waves in Shandong Province showed a significant increasing trend (P < 0.05) at a rate of approximately 0.072/10a; the combined sensitivity significantly decreased (P < 0.05) at a rate of approximately 0.137/10a, and the combined adaptability continued to increase at a rate of approximately 0.481/10a. (3) The combined vulnerability to summer droughts and heat waves in the western inland area of Shandong Province was high and gradually decreased toward the southeastern coast. The overall decrease trend was nonsignificant with a decrease of approximately 0.126/10a, and the decline rate decreased from northwest to southeast, in which Laiwu, Yantai, Jinan, and Zibo cities exhibited a significant decreasing trend (P < 0.05). Although the compound vulnerability of Shandong Province has decreased insignificantly, the frequency of combined drought and heat wave events has increased, and the combined vulnerability will increase in the future. [ABSTRACT FROM AUTHOR]

In this study, based on hourly ERA5 reanalysis data from July to September, from 1971 to 2020, for Shandong Province, we used mathematical statistical analysis, the Mann–Kendall nonparametric statistical test, cluster analysis, and other methods to extract and analyze the spatiotemporal variation characteristics and causes of typical extreme precipitation events. The results indicated the following: (1) The total number and duration of precipitation events show a nonsignificant upward trend, while the average and extreme rainfall intensities show a nonsignificant downward trend. (2) Extreme precipitation events are primarily concentrated in Qingdao, Jinan, Heze, and Binzhou, with fewer events occurring in central Shandong Province. (3) Extreme precipitation events are classified into four types (namely, patterns I, II, III, and IV). Pattern I exhibits two rain peaks, with the primary rain peak occurring after the secondary rain peak. Similarly, pattern II also displays two rain peaks, with equivalent rainfall amounts for both peaks. In contrast, pattern III has multiple, evenly distributed rain peaks. Finally, pattern IV shows a rain peak during the first half of the precipitation event. Pattern I has the highest occurrence probability (46%), while pattern IV has the lowest (7%). (4) The spatial distributions of the different rain patterns are similar, with most being found in the eastern coastal and western regions. (5) Extreme precipitation events result from interactions between large-scale circulation configurations and mesoscale convective systems. The strong blocking situation and significant circulation transport at middle and low latitudes in East Asia, along with strong convergent uplift, abnormally high specific humidity, and high-water-vapor convergence centers, play crucial roles in supporting large-scale circulation systems and triggering mesoscale convective systems. [ABSTRACT FROM AUTHOR]

The expansion of impervious surface area (ISA) in megacities of China often leads to land surface temperature (LST) aggregation effects, which affect living environments by impacting thermal comfort levels, thus becoming an issue of public concern. However, from an urban–rural synchronous comparison perspective, the study of LST responses to ISA changes is still lacking in the central coastal megalopolises of China. To solve this issue, a collaborative methodology of artificial digitization—fully constrained least squares mixed pixel decomposition—split-window algorithm—PCACA model was established for Qingdao using land use dataset and remote sensing images. The conclusions are below. Long time series of land use monitoring indicated that the expansion ratios of urban and rural areas were 131.29% and 43.42% in the past 50 years (i.e., from 1970 to 2020). Within urban and rural areas, a synchronous ISA increase was observed, with ratios of +9.14% (140.55 km2) and +7.94% (28.04 km2), respectively. Higher ratios and area changes were found in the urban regions, and a similar ISA change pattern in both urban and rural regions was captured by the ISA horizontal epitaxial expansion and vertical density enhancement. Further, the horizontal gradient effect displayed that the mean LSTs were 28.75 °C, 29.77 °C and 31.91 °C in the urban areas and 28.73 °C, 29.66 °C and 31.65 °C in the rural areas in low-, medium-, and high-density ISAs. The vertical density effect showed that the LST change was 1.02 °C and 2.14 °C in the urban areas but 0.93 °C and 1.99 °C in the rural areas during the ISA-density transition from low- to medium- and from medium- to high-density, respectively. Potential surface thermal indicators were assessed, and the urban regions displayed higher sensible heat flux (280.13 W/m2) compared to the rural regions (i.e., 274.76 W/m2). The mechanism effect of the ISA changes on LST in the urban and rural regions was revealed. These findings form a new comparative perspective of the urban–rural synchronous change in the central coastal megalopolis of China and can provide a practical reference for relevant studies. [ABSTRACT FROM AUTHOR]

As ideal tracers of the global water cycle, water stable isotopes show a temperature effect at mid-high latitudes and an "amount effect" at mid-low latitudes. However, the interpretation of stable isotopes in the monsoon region remains uncertain. To understand the factors controlling daily precipitation δ18O values in the midlatitude monsoon region, continuous observations of precipitation isotopes in Rizhao from 2021 to 2022 were made. We investigate the drivers of precipitation δ18O by analyzing their relationship with temperature, precipitation amount, relative humidity, and outgoing longwave radiation (OLR) data. Back trajectory analysis with the HYSPLIT model based on precipitation events was also used to trace moisture sources. The results show that the controlling factors of stable isotopes in precipitation vary during different seasons. In the spring–summer season, precipitation δ18O is associated with heavy precipitation over the region of the Asian continent, the tropical Indian Ocean, the South China Sea, and the local sampling site, consistent with the spatial patterns of OLR, indicating that convection activities are the main driver of precipitation isotopic values in those seasons. In the autumn–winter season, the positive correlation between precipitation δ18O and local and regional-scale temperature confirms that Rayleigh distillation controls moisture transport. These findings improve regional-scale understanding of hydrological cycles in the East Asian mid-latitude monsoon region and have the potential to improve our understanding of isotopic variations in the proxy archives of the East Asian monsoon region. [ABSTRACT FROM AUTHOR]

This study investigated the seasonal variation in the atmospheric response to oceanic mesoscale eddies in the North Pacific Subtropical Countercurrent (STCC) and its mechanism, based on satellite altimetric and reanalysis datasets. Although mesoscale eddy in the study area is more active in summer, the sea surface temperature (SST) anomaly associated with mesoscale eddies is more intense and dipolar in winter, which is largely due to the larger background SST gradient. Similarly, the impact of the oceanic eddy on sea surface wind speed and heat flux is strongest in winter, whereas its effect on precipitation rate is more significant in summer. The study revealed that the SST gradient in STCC could impact the atmosphere layer by up to 800 hPa (900 hPa) in boreal winter (summer) through the dominant vertical mixing mechanism. Moreover, the intensity of the SST gradient causes such seasonal variation in mesoscale air-sea coupling in the study region. In brief, a stronger (weaker) background SST gradient field in wintertime (summertime) leads to a larger (smaller) eddy-induced SST anomaly, thus differently impacting atmosphere instability and transitional kinetic energy flux over oceanic eddies, leading to seasonal variation in mesoscale air-sea coupling intensity. [ABSTRACT FROM AUTHOR]

Drought-induced risk has attracted the attention of many scholars, but the risk of combined events caused by drought and high-temperature heat waves still needs further study. Based on MODIS products and meteorological data, the spatiotemporal variation characteristics of summer drought and high-temperature heat waves in the North China Plain from 2000 to 2018 were analyzed by the standardized precipitation evapotranspiration index (SPEI), crop water stress index (CWSI) and high-temperature threshold, and their combined-events risk was evaluated. The results showed that (1) from 2000 to 2018, summer drought in the North China Plain became more severe. Especially in Henan, Anhui and Jiangsu Provinces, drought increased significantly. (2) From 2000 to 2018, the frequency and intensity of high-temperature heat wave events in the North China Plain gradually increased at rates of 0.28 times/10 year and 1.6 °C/10 year, respectively. (3) The slightly high risk and high risk caused by summer drought were mainly distributed in Hebei Province and Tianjin Municipality in the north, and the risk change was characterized by a decrease in the north and an increase in the south. (4) The combined-events risk of summer drought and high-temperature heat waves did not increase significantly, with an increase rate of approximately 0.01/10 year. Among them, the increase rate of combined-events risk in Henan Province was the largest (0.14/10 year), followed by the obvious increase in northern Anhui, Jiangsu and southern Shandong, while the risk in Beijing showed a decreasing trend. The research results have scientific guiding significance for formulating disaster prevention and reduction strategies. [ABSTRACT FROM AUTHOR]

Much attention has recently been devoted to the qualitative relationship between climate factors and drought; however, the influences of climate variability, land-use/cover changes (LUCC), and other human activities on drought have rarely been quantitatively assessed. Based on the Soil and Water Assessment Tool (SWAT) model and the Palmer drought severity index (PDSI), this study presents a framework to quantify drought changes in an attribution study, and quantifies the effects of climate factors, LUCC, and other human activities on drought in a typical basin (Yihe River) in eastern China from 1980 to 2019. (1) The SWAT–PDSI results revealed a slight decreasing trend from 1980 to 2019, indicating that the degree of drought increased—especially in the middle of the basin. (2) The precipitation in the basin exhibited a downward trend (−2.7 mm/10 a), while the temperature exhibited a significant increasing trend (0.13 °C/10 a, p < 0.05). Over the past 40 years, LUCC in the Yihe River Basin was mainly characterized by a reduction in the dryland area (149 km2) and an increase in the built-up area (135 km2), which changed by −1.77% and 18.96%, respectively. (3) Climate fluctuation was the main driving factor of drought change, with a contribution rate ranging from 68 to 84%, and the contribution to drought gradually increased. Among the various factors, the contribution of temperature exceeded that of precipitation from 2010 to 2019, suggesting that temperature has become the most important climate factor affecting drought. The contribution rates of LUCC to drought changes over the periods 1990–1999, 2000–2009, and 2010–2019 were 7.8%, 18%, and 12.6%, respectively. This indicates that the relative contributions of other human activities to drought changes gradually decreased. This study refines the drought attribution framework, which could provide scientific support for the quantitative attribution of drought and the formulation of disaster prevention and reduction strategies. [ABSTRACT FROM AUTHOR]

Understanding the contributions of potential drivers on runoff is essential for the sustainable management of water resources; however, the impacts of climate variability and human activities on runoff at inter-annual and inter-decadal scales have rarely been assessed quantitatively. To achieve this goal, this study develops a nonlinear hybrid model, which integrates extreme-point symmetric mode decomposition (ESMD), back propagation artificial neural networks (BPANN) and weights connection method. ESMD allows to separate the times series of drivers and runoff into different time scales. BPANN is then used to simulate the relation between the drivers and runoff at each time scale separately. Weights connection method is employed to quantify the impacts of climate variability and human activities on runoff. The performance of this proposed model is compared with multiple linear regression (MLR). The mountainous area of the Hotan River Basin is selected as case study area. Results reveal that runoff exhibits significant fluctuations at inter-annual (2 and 9 years) and inter-decadal (14 years) scales. Climate variables are responsible for 81% of the runoff variations, while human activities account for 8%. The nonlinear hybrid model substantially outperforms MLR in all performance measures. We attribute this improvement to the ability of the proposed model to represent nonlinear relations and to simulate the association between drivers and runoff at different time scales. For instance, water vapor affects runoff positively at the inter-annual time scale but negatively at the inter-decadal time scale. Such opposing relations cannot be represented by MLR or many other, more traditional methods. [ABSTRACT FROM AUTHOR]

A novel Ag3PO4/ZnO/diatomite composite photocatalyst was prepared by simple ultrasonic dispersion-precipitation method. The structure, composition, microstructure and optical properties of the catalysts were characterized by means of X-ray diffraction (XRD), fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). Moreover, the visible light catalytic performance of the catalyst was investigated with tetracycline hydrochloride (TC) as the degradation target. The results showed that the photocatalytic activity of Ag3PO4/ZnO/diatomite in the degradation of TC, which can reach 90.99% removal rate of 30 mg/L TC under visible light, was significantly better than that of monomer catalysts and Ag3PO4/ZnO catalyst. Meanwhile, it exhibited better stability compared with pure Ag3PO4. The improvement of visible light catalytic activity and stability of Ag3PO4/ZnO/diatomite is mainly attributed to the catalyst's better adsorption capacity, wider spectral response range, more efficient photo-generated electrons and holes migration and less photocorrosion. The results of free radical trapping experiments show that the main active species of the reaction system are h+ and •O2−. [ABSTRACT FROM AUTHOR]

It is of great significance to quantitatively assess the impact of mountain precipitation on inland river runoff in data scarce regions. Based on the corrected TRMM precipitation and runoff data, a variety of statistical methods were used to identify which areas of precipitation have an important impact on runoff in the Hotan River Basin, and to evaluate the effects that precipitation changes have on runoff at low, mid, high, and extremely high altitudes of mountainous areas. The results showed that: 1) From 1998 to 2015, the annual runoff showed a fluctuating upward trend with a rate of 11.21 × 108 m3/10 a (P < 0.05). Runoff in every season also had an increasing trend, with summer runoff the most significant at a rate of 6.09 × 108 m3/10 a. 2) The annual runoff and precipitation changes had certain synchronization, with a correlation coefficient of 0.45 (P < 0.05). Among them, the correlations between precipitation and runoff changes were highest at low and mid- altitudes, with coefficients of 0.62 and 0.55, respectively (P < 0.05). 3) 65.95% of the regional precipitation at low altitudes and 48.34% at high altitudes were significantly correlated with runoff (P < 0.05), while only 38.84% and 26.58% of regional precipitation levels at mid- and extremely high altitudes were significantly correlated with runoff. 4) The annual precipitation change in the basin was 1%, which would cause the annual runoff to change by 0.24%. In 1998–2015, the change of annual runoff caused by precipitation change at high altitudes was largest at a rate of −6.01%; the change rates of annual runoff caused by precipitation change in the low, mid-, and extremely high altitudes were −3.66%, −3.62%, and −3.67%, respectively. The results have significant scientific guidance for water resource management in arid basins. [ABSTRACT FROM AUTHOR]

We use data on the freezing level height (FLH) and summer runoff in the Hotan River, China, from 1960 to 2013, to analyse the nonlinear relationships of atmospheric and hydrological factors at different time scales, by employing three nonlinear decomposition methods. Six hybrid prediction models are established by combining linear regression and back-propagation artificial neural network (BPANN) models. The decomposition results by three nonlinear methods are compared, indicating that the extreme-point symmetric mode decomposition (ESMD) method ensures the best prediction capacity. The runoff and FLH have periods of 3 and 6 years, respectively, at the inter-annual scale, which pass the significance test of 0.05 (P < 0.05) by using the Monte Carlo method, although there were slight differences in the periods at the inter-decadal scale. Among the six models, ESMD-BPANN exhibits the highest accuracy, with good reliability and resolution, according to several performance indicators. The ESMD-BPANN model is thus selected for the simulation and prediction of runoff. [ABSTRACT FROM AUTHOR]

Under the impacts of climate change and human activities, great uncertainties still exist in the response of climate extremes, especially in Central Asia (CA). In this study, we investigated spatial-temporal variation trends and abrupt changes in 17 indices of climate extremes, based on daily climate observations from 55 meteorological stations in CA during 1957-2005. We also speculated as to which atmospheric circulation factors had the greatest impacts on climate extremes. Our results indicated that the annual mean temperature (Tav), mean maximum and minimum temperature significantly increased at a rate of 0.32ºC/10a, 0.24ºC/10a and 0.41ºC/10a, respectively, which was far higher than the increasing rates either globally or across the Northern Hemisphere. Other temperature extremes showed widespread significant warming trends, especially for those indices derived from daily minimum temperature. All temperature extremes exhibited spatially widespread rising trends. Compared to temperature changes, precipitation extremes showed higher spatial and temporal variabilities. The annual total precipitation significantly increased at a rate of 4.76 mm/10a, and all precipitation extremes showed rising trends except for annual maximum consecutive dry days (CDD), which significantly decreased at a rate of -3.17 days/10a. On the whole, precipitation extremes experienced slight wetter trends in the Tianshan Mountains, Kazakhskiy Melkosopochnik (Hill), the Kyzylkum Desert and most of Xinjiang. The results of Cumulative Deviation showed that Tav and Txav had a significant abrupt change around 1987, and all precipitation indices experienced abrupt changes in 1986. Spearman's correlation analysis pointed to Siberian High and Tibetan Plateau Index_B as possibly being the most important atmospheric circulation factors affecting climate extremes in CA. A full quantitative understanding of these changes is crucial for the management and mitigation of natural hazards in this region. [ABSTRACT FROM AUTHOR]

Scientists generally believe that human activities and atmospheric circulations have important effects on wind speed changes; however, the main driving factors of wind speed at different times and in different areas are far from clear. Here, based on monthly wind speed data in the northwestern China during 1980-2012, we analyzed the spatiotemporal variations in wind speed and their relationship with atmospheric circulations. The results showed that (1) annual surface wind speed (SWS) displayed a decreasing trend (− 0.032 m/s/10a) during 1980-2012; SWS increased only in winter. In contrast, annual upper-air wind speed (UWS) exhibited an increasing trend; UWS presented a declining trend only in summer. (2) Human activities were likely the major cause of decrease in SWS, whereas the enhancement of the Asian Meridional Circulation (AMC, R = 0.50, P < 0.01) was an important factor for the increase in SWS in winter. (3) Annual UWS exhibited an increasing trend (0.176 m/s/10a) in the troposphere. This trend was closely related to the weakening of the Eurasian Zonal Circulation (EZC, R = − 0.52, P < 0.01) and the enhancement of the Siberian High (SH, R = 0.48, P < 0.01) during the winter, whereas the enhancement of the Eurasian Zonal Circulation (EZC, R = − 0.60, P < 0.001) in summer was the prime reason for the decrease in UWS in summer. (4) UWS increased significantly (0.38 m/s/10a) in the lower stratosphere, and this trend was mainly associated with the weakening of the Pacific Decadal Oscillation (PDO, R = − 0.40, P < 0.05). [ABSTRACT FROM AUTHOR]

An extremum search algorithm of bidirectional constant speed scanning is proposed in this article, which can be applied to ATSM-CFR engine for automatic determination of octane number. Firstly, the algorithm searches controlled variable forwardly at a constant speed until a peak appears; secondly, searching it reversely at the same speed until a valley appears; lastly, continue the reverse search and determine next search time based on the time difference between the valley time and the peak time to obtain optimal control. The experiment result shows that the search algorithm has good control performance in the determination of octane number. [ABSTRACT FROM AUTHOR]

ABSTRACT: Climate systems have both nonlinear and non‐stationary characteristics, and it is important to develop methods to reveal the nonlinear trends in these systems. Based on synthetic data with known signals and a precipitation anomaly time series from 74 meteorological stations in an arid region of northwest China (ARNC) from 1960 to 2015, the latest extreme‐point symmetric mode decomposition (ESMD) and ensemble empirical mode decomposition (EEMD) methods were employed to conduct multi‐scale mode decomposition. The results showed that both the ESMD and EEMD methods can separate synthetic signals and extract the nonlinear trends of precipitation in ARNC and can thus provide reliable decomposition results. This article employed the ESMD method to analyse the spatial and temporal variation features of nonlinear precipitation trends in ARNC from 1960 to 2015. The results indicated that over the past 50+ years, the overall precipitation in ARNC has exhibited an apparent nonlinear upwards trend. In addition, its changes have exhibited oscillation periods of 3, 6, and 11 years. The periods of the three components are significant (p < 0.05), and the variance contribution rate of the first intrinsic mode function (IMF1) is the largest, reaching 58%. Furthermore, there are obvious spatial differences in the nonlinear trends of average annual precipitation: northern Xinjiang has had a mainly rising trend; southern Xinjiang has had mainly rising and decreasing–rising trends; and the precipitation changes in the Hexi Corridor have been quite complicated. The ESMD method can reflect integrated changes in the nonlinear trends of precipitation over different time scales and has important practical significance and scientific value for revealing the complicated structural features of climate systems. [ABSTRACT FROM AUTHOR]

During the recent 50 years, in response to global warming, nearly all of the rivers in the arid region of northwest China have shown significant increasing trends in runoff. However, runoff in the Hotan River has shown a slight decreasing trend that corresponded to a rate of −0.18 × 108 m3/decade for the same period. Here, based on an analysis of runoff from mountain pass hydrologic stations and precipitation during 1960–2009, as well as measurements of upper‐air temperature (UAT) from the Hotan sounding station (1960–2011) and MODIS land surface temperature (LST) of the mountainous area (2001–2011), we found that the annual runoff in the Hotan River was mainly determined (75%) by summer runoff. We also determined that the summer runoff was strongly associated (correlation coefficient: R = 0.78, p < 0.001) with summer UAT at 500 hPa and mountain LST (R = 0.69, p < 0.001) during 1960–2009. Because the largest proportion of runoff in the Hotan River stems from glacial meltwater, we suggest that the decreasing trends exhibited by the UAT in the mid‐lower troposphere and the LST within the mountainous area in summer are the main reasons why runoff shows a slight decreasing trend over the past half century. [ABSTRACT FROM AUTHOR]

Land use/cover changes (LUCCs) are an important cause of regional climate changes, but the contribution of LUCCs to regional climate changes is not clear. In this study, the Weather Research and Forecasting (WRF) model and statistical methods were used to investigate changes in meteorologic variables in January, April, July, and October 2013 due to local LUCCs from 1990 to 2010 in southern Shandong province, China. The results indicate that the WRF model simulates temperatures in the region well, with high correlation coefficients (0.86-0.97, p < 0.001) between the modeled and measured values. The model simulates precipitation less well, with correlation coefficients of 0.41-0.91, but they are all at statistically significant levels, with p < 0.05. During the 20-year period, the LUCCs in the study area consisted mainly of conversions from dry land to urbanized land (747.3 km) and bare/sparse vegetation (132.4 km). The LUCCs caused a 0.16 °C temperature increase in January and October and 0.01 and 0.18 °C temperature decreases in April and July, respectively. The range of temperature changes over mixed forest and water bodies due to the LUCCs was wide (0.39-1.31 °C) and was narrower over deciduous broadleaf forest and wetland (0.01 to 0.06 °C). The LUCCs did not change the precipitation greatly in January, April, and October but did affect the precipitation in July substantially, causing a decrease of 23.71 mm. The LUCCs did not affect wind speed and direction substantially during these four months: average wind speeds increased by 0.02 and 0.01 m/s in January and October, respectively, and decreased by 0.02 and 0.05 m/s in April and July, respectively. Overall, The LUCCs affected spring temperatures the least and summer precipitation the most. [ABSTRACT FROM AUTHOR]

Climate change and water resource issues are global problems of common concern to the international community, and they are major bottlenecks affecting the eco-environment and sustainable socio-economic development in the arid region of Northwest China. On the basis of results from previous studies, this paper points out that the unique landscape of Northwest China increases the complexity and uncertainty of the climate system. This paper analyzes the key constraints on socio-economic development and ecological security in the region, discusses the impact of climate change on water resources in Northwest China, identifies common themes and the main problems present in research on climate change and water resources in the arid northwest region, and finally, based on the importance and urgency of conducting research on the region's water resources, proposes scientific problems that need to be addressed: first, the impact of climate change on the formation, conversion and future trends of water resources in the region; second, bidirectional coupling of high-resolution regional climate models and water cycle models of arid region land surface patterns; third, the impact of climate change and human activities on water resources of the arid northwest region. Through consideration and discussion of the above, this paper seeks to further clarify specific areas of research on pressing issues related to climate change and water resources in Northwest China, so as to establish a solid scientific basis for significantly enhancing our ability to respond to climate change and water shortages. [ABSTRACT FROM AUTHOR]

Much attention has recently been focused on the effects that precipitation and potential evapotranspiration (PET) have had on runoff change; however, the influence of temperature on runoff needs to be further studied. We attempted to employ the improved elasticity method to evaluate the effects of climate factors (CF, especially temperature) on runoff change for Aksu River in the arid region of northwest China. Data from Aksu River in the arid region of northwest China were analyzed to investigate changes in annual runoff and CF during the period of 1960-2010. The key findings of this study indicated that the annual runoff had a significant ( P < 0.01) increasing trend with a rate of 3.78 × 10 m/decade, and the temperature and precipitation also exhibited significant rising trends, at a rate of 0.28 °C/decade ( P < 0.01) and 15.11 mm/decade ( P < 0.05), respectively, while PET showed a decreasing trend (22.66 mm/decade, P < 0.01). Step change point in runoff occurred in the year 1993. Thus, we employed the mean runoff and climate factors during the period 1960-1993 as the benchmark value to measure the change. In 1994-2010, mean runoff increased by 22 %. Results also revealed that temperature rising was the most important factor that increased runoff with contribution of 45 %, while precipitation and PET were responsible for 22 and 27 % of the runoff change, respectively, indicating that the runoff of increasing percentage only accounted for 6 % owing to human activities and other factors, and showed that climate variability was the main reason for the runoff change in Aksu River. [ABSTRACT FROM AUTHOR]

CD147, also known as extracellular matrix metalloproteinase inducer, is a widely distributed cell surface glycoprotein that belongs to the immunoglobulin superfamily. CD147 has been proved to be enriched on the surface of many tumor cells, promoting tumor growth, invasion and metastasis by its stimulation effect on adjacent fibroblasts to produce matrix metalloproteinases. In this study, we aimed to explore the expression pattern of CD147 in glioblastoma (GBM) and investigate whether it could be used to assess subsequent prognosis of patients. For that, we recruited a total of 206 patients with pathologically confirmed GBM and 36 normal control brain tissue specimens. The expression of CD147 in GBM and normal tissues was investigated by immunohistochemistry assay. Genetic factors including MGMT and IDH1 mutation were also investigated to justify the prognostic significance of CD147. Results showed that CD147 expression was increased in GBM compared with that in normal tissues. Kaplan-Meier analysis showed that increased CD147 expression was associated with poor overall survival of patients with GBM. Moreover, Cox's proportional hazards model revealed that CD147 expression was an independent and significant prognostic marker of overall survival in GBM patients. These results proved that CD147 expression was relatively abundant in GBM and can be potentially used to predict prognosis and treatment response in GBM patients. [ABSTRACT FROM AUTHOR]

Using 51 meteorological stations in the arid region of northwest China in the mountain, oasis, and the desert areas obtained from 1960 to 2010, this paper conducted a comparative analysis for detecting temperature and precipitation changes in the diverse environments. In recent 50 years, temperature has increased at 0.325, 0.339, and 0.360 °C per decade in the mountain, oasis, and the desert areas, respectively; and also, precipitation has increased at 10.15, 6.29, and 0.87 mm per decade, but in which the increasing trend of precipitation in desert area was not significant. Before the 1990s, the increase in temperature was the fastest in the desert area, up to 0.214 °C per decade, but was the slowest in the mountain area, only 0.103 °C per decade. The temperature rising was faster after the 1990s, 0.606 °C per decade, in the oasis area was fastest, but was the slowest in the desert region with 0.402 °C per decade. The precipitation in each area was stable from 1960 to 1986, but an increase in the oasis and mountain area was larger from 1987 to 2010. [ABSTRACT FROM AUTHOR]

Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, data from the Kaidu River Basin in the arid region of northwest China were analyzed to investigate changes in annual runoff during the period of 1960-2009. The nonparametric Mann-Kendall test and the Mann-Kendall-Sneyers test were used to identify trend and step change point in the annual runoff. It was found that the basin had a significant increasing trend in annual runoff. Step change point in annual runoff was identified in the basin, which occurred in the year around 1993 dividing the long-term runoff series into a natural period (1960-1993) and a human-induced period (1994-2009). Then, the hydrologic sensitivity analysis method was employed to evaluate the effects of climate variability and human activities on mean annual runoff for the human-induced period based on precipitation and potential evapotranspiration. In 1994-2009, climate variability was the main factor that increased runoff with contribution of 90.5 %, while the increasing percentage due to human activities only accounted for 9.5 %, showing that runoff in the Kaidu River Basin is more sensitive to climate variability than human activities. This study quantitatively distinguishes the effects between climate variability and human activities on runoff, which can do duty for a reference for regional water resources assessment and management. [ABSTRACT FROM AUTHOR]

Water resources in the arid land of Northwest China mainly derive from snow and glacier melt water in mountainous areas. So the study on onset, cessation, length, temperature and precipitation of snowmelt period is of great significance for allocating limited water resources reasonably and taking scientific water resources management measures. Using daily mean temperature and precipitation from 8 mountainous weather stations over the period 1960-2010 in the arid land of Northwest China, this paper analyzes climate change of snowmelt period and its spatial variations and explores the sensitivity of runoff to length, temperature and precipitation of snowmelt period. The results show that mean onset of snowmelt period has shifted 15.33 days earlier while mean ending date has moved 9.19 days later. Onset of snowmelt period in southern Tianshan Mountains moved 20.01 days earlier while that in northern Qilian Mountains moved only 10.16 days earlier. Mean precipitation and air temperature increased by 47.3 mm and 0.857°C in the mountainous areas of Northwest China, respectively. The precipitation of snowmelt period increased the fastest, which is observed in southern Tianshan Mountains, up to 65 mm, and the precipitation and temperature in northern Kunlun Mountains increased the slowest, an increase of 25 mm and 0.617°C, respectively, while the temperature in northern Qilian Mountains increased the fastest, increasing by 1.05°C. The annual runoff is also sensitive to the variations of precipitation and temperature of snowmelt period, because variation of precipitation induces annual runoff change by 7.69% while change of snowmelt period temperature results in annual runoff change by 14.15%. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the therapeutic effect of Piweiping capsule (PWPC) in treating patients with metaplasia of gastric mucosa and explore its mechanism. Method: One hundred and forty-three patients were diagnosed as chronic superficial atrophic gastritis of gastric antrum or with metaplasia by means of gastroscopic observation with pathological biopsy examination. They were divided into 4 types (type I - IV) according to Syndrome Differentiation of traditional Chinese medicine, and each type was subdivided according to treatment into 2 groups, 75 in the PWPC group and 68 in the Sanjiu Weitai ( ) group. Patients of PWPC group were in accordance with the type to which they belong treated with PWPC I, II, HI, IV respectively, while patients of SJWT group were all treated with SJWT. After 3 - 6 months of treatment, the clinical effect, pathological examination of gastric mucosa and some other parameters were observed. Results: The improvements of gastric mucosa cyclic adenosing monophosphate (cAMP), deoxyribonucleic acid (DNA),H-thymopyrimidine nucleoside and lymphocyte transformation of the treatment group were all superior to those of SJWT group, P < 0.05-0.001. In the PWPC group, the curative rate and total effective rate on symptom were 49.3 % and 92.0% respectively, and the curative rate and total effective rate on intestinal metaplasia were 45.3 % and 62.7%. As for the SJWT group, they were 29.4%, 67.6%, 10.3% and 29.4% respectively. The difference between the two groups was significant, P < 0.001. Conclusion: PWPC could reverse the intestinal metaplasia through improving the gastric cAMP, DNA and strengthening the cellular immunity and the effect would be enhanced when the treatment was based on Syndrome Differentiation. [ABSTRACT FROM AUTHOR]

Winter Eurasian cooling after the mid-1990s has been verified by numerous studies, although in recent decades, the mid-latitudes of the Northern Hemisphere have been rapidly warming globally. Because the cooling is not uniform at different spatial and temporal scales, over time, this change may not truly reflect the nature of climate fluctuations. Here, by using three types of data (reanalysis, weather station, and remote sensing image data) to assess variations in Eurasian seasonal cooling, we examine the causes of these changes. During a 30-year climatology (1989–2018), we show that a significant (P < 0.05) abrupt change in the autumn Eurasian air temperature trend occurred in 2003. Our results suggest that from 2004–2018, the autumn Eurasian temperature reveals a significant cooling trend (P < 0.05). We demonstrate that the autumn cooling in Eurasia is likely influenced by the Pacific Decadal Oscillation (PDO) and Siberian high (SH). Since 2004, the strengthening of the PDO and SH explains approximately 54% and 18% of the autumn cooling in Eurasia, respectively. We also find that the cooling in autumn is stronger than that in winter. In the last years, an extensive winter cooling over central Eurasia has been discussed widely. Here, the authors show that from 2004–2018, the Eurasian cooling in autumn is stronger than that in winter, and that this autumn cooling is likely influenced by the Pacific Decadal Oscillation and the Siberian high. [ABSTRACT FROM AUTHOR]

Global Satellite Mapping of Precipitation (GSMaP), Climate Hazards Group InfraRed Preconception with Station data (CHIRPS), Tropical Rain Measurement Mission Multisatellite Precipitation Analysis (TRMM 3B42 V7) and Rainfall Estimation from Soil Moisture Observations (SM2RAIN) are satellite precipitation products with high applicability, but their applicability in hydrological research in arid mountainous areas is not clear. Based on precipitation and runoff data, this study evaluated the applicability of each product to hydrological research in a typical mountainous basin (the Qaraqash River basin) in an arid region by using two methods: a statistical index and a hydrological model (Soil and Water Assessment Tool, SWAT). Simulation results were evaluated by Nash efficiency coefficient (NS), relative error (PBIAS) and determination coefficient (R2). The results show that: (1) The spatial distributions of precipitation estimated by these four products in the Qaraqash River basin are significantly different, and the multi-year average annual precipitation of GSMaP is 97.11 mm, which is the closest to the weather station interpolation results. (2) On the annual and monthly scales, GSMaP has the highest correlation (R ≥ 0.82) with the observed precipitation and the smallest relative error (BIAS < 6%). On the seasonal scale, the inversion accuracy of GSMaP in spring, summer and autumn is significantly higher than other products. In winter, all four sets of products perform poorly in estimating the actual precipitation. (3) Monthly runoff simulations based on SM2RAIN and GSMaP show good fitting (R2 > 0.6). In daily runoff simulation, GSMaP has the greatest ability to reproduce runoff changes. The study provides a reference for the optimization of precipitation image data and hydrological simulation in data-scarce areas. [ABSTRACT FROM AUTHOR]

Droughts are one of the costliest natural disasters. Reliable drought monitoring and prediction are valuable for drought relief management. This study monitors and predicts droughts in Xinjiang, an arid area in China, based on the three drought indicators, i.e., the Standardized Precipitation Index (SPI), the Standardized Soil Moisture Index (SSMI) and the Multivariate Standardized Drought Index (MSDI). Results indicate that although these three indicators could capture severe historical drought events in the study area, the spatial coverage, persistence and severity of the droughts would vary regarding different indicators. The MSDI could best describe the overall drought conditions by incorporating the characteristics of the SPI and SSMI. For the drought prediction, the predictive skill of all indicators gradually decayed with the increasing lead time. Specifically, the SPI only showed the predictive skill at a 1-month lead time, the MSDI performed best in capturing droughts at 1- to 2-month lead times and the SSMI was accurate up to a 3-month lead time owing to its high persistence. These findings might provide scientific support for the local drought management. [ABSTRACT FROM AUTHOR]

In light of ongoing changes in how humans interact with the environment, it is of great importance to quantitatively assess the impact of land use and cover change (LUCC) on ecosystems. Using a variety of methods, we analyzed land-use patterns and ecosystem service values (ESV) in 1990, 2000, and 2010; normalized difference vegetation index (NDVI) from 1982 to 2010 in the arid region of Northwest China; and quantitatively assessed the effects of LUCC on changes in NDVI and ESV. The results indicate the following: (1) From 1990 to 2010, the rate of increase in the amount of cropland and urban land was highest at 19.13% and 18.25%, respectively, followed by the rate for water cover (5.10%) and forest land (3.55%), while grassland experienced a reduction of 2.25%. (2) From 1990 to 2010, the total ESV increased by 1.82%. Changes in the amount of water cover and cropland were responsible for an increase in ESV of 1.42% and 1.10%, respectively, while the change in the amount of grassland was responsible for a decrease of 1.09%. Based on this, it seems likely that climate variability is a substantial cause of change in ESV. (3) From 1982 to 2010, NDVI showed an overall increase, first increasing significantly between 1982 and 2002 and then decreasing somewhat from 2002 to 2010. From 1990 to 2010, the contribution rate of LUCC to change in total NDVI was 26.74%, indicating that the contribution rate of climate variability to NDVI change was up to 73.26%. Therefore, over those 20 years, climate warming and humidification had an important impact on the development of ecosystems in the arid region of Northwest China. [ABSTRACT FROM AUTHOR]