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The Tibetan Plateau, housing 20% of China's wetlands, plays a vital role in the regional carbon cycle. Examining the phenological dynamics of wetland vegetation in response to climate change is crucial for understanding its impact on the ecosystem. Despite this importance, the specific effects of climate change on wetland vegetation phenology in this region remain uncertain. In this study, we investigated the influence of climate change on the end of the growing season (EOS) of marsh wetland vegetation across the Tibetan Plateau, utilizing satellite‐derived Normalized Difference Vegetation Index (NDVI) data and observational climate data. We observed that the regionally averaged EOS of marsh vegetation across the Tibetan Plateau was significantly (p <.05) delayed by 4.10 days/decade from 2001 to 2020. Warming preseason temperatures were found to be the primary driver behind the delay in the EOS of marsh vegetation, whereas preseason cumulative precipitation showed no significant impact. Interestingly, the responses of EOS to climate change varied spatially across the plateau, indicating a regulatory role for hydrological conditions in marsh phenology. In the humid and cold central regions, preseason daytime warming significantly delayed the EOS. However, areas with lower soil moisture exhibited a weaker or reversed delay effect, suggesting complex interplays between temperature, soil moisture, and EOS. Notably, in the arid southwestern regions of the plateau, increased preseason rainfall directly delayed the EOS, while higher daytime temperatures advanced it. Our results emphasize the critical role of hydrological conditions, specifically soil moisture, in shaping marsh EOS responses in different regions. Our findings underscore the need to incorporate hydrological factors into terrestrial ecosystem models, particularly in cold and dry regions, for accurate predictions of marsh vegetation phenological responses to climate change. This understanding is vital for informed conservation and management strategies in the face of current and future climate challenges. [ABSTRACT FROM AUTHOR]

Understanding the spatiotemporal variation in vegetation phenology of freshwater marshes and its response to climate change is significant to evaluate the global carbon cycling. Based on the climate and satellite‐derived vegetation index data, this work investigated the temporal and spatial variation of spring phenology and its response to climatic change in freshwater marshes of the Tibetan Plateau. We found that the start date of vegetation growing season (SOS) showed a significant advancing trend of 3.4 d decade−1 from 2001 to 2019 in freshwater marshes of the Tibetan Plateau. The increase of spring daytime and nighttime temperatures could advance the vegetation SOS over the marshes of the Tibetan Plateau. However, the effects of day maximum and night minimum temperature on freshwater marsh SOS were divergent at different altitudes: the advancing effect of warming night‐time and daytime temperature on the SOS was more significant in the regions below and above 4000 m, respectively. [ABSTRACT FROM AUTHOR]

Sanjiang Plain is the largest marsh distribution area of China, and marshes in this region significantly affect regional carbon cycle and biodiversity protection. The vegetation phenology of marsh significantly affects the energy exchange and carbon cycle in that region. Under the influence of global climatic change, identifying the changes in phenology and their responses to climatic variation in marshes of Sanjiang Plain is essential for predicting the carbon stocks of marsh ecosystem in that region. Using climate and NDVI data, this paper analyzed the spatiotemporal variations in the start (SOS), end (EOS), and length (LOS) of vegetation growing season and explored the impacts of climatic variation on vegetation phenology in marshes of Sanjiang Plain. Results showed that the SOS advanced by 0.30 days/a, and EOS delayed by 0.23 days/a, causing LOS to increase significantly (p <.05) by 0.53 days/a over marshes of Sanjiang Plain. Spatially, the large SOS advance and EOS delay resulted in an obvious increasing trend for LOS in northern Sanjiang Plain. The rise of spring and winter temperatures advanced the SOS and increased the LOS, and the rise in temperature in autumn delayed the EOS in marshes of Sanjiang Plain. Our findings highlight the necessity of considering seasonal climatic conditions in simulating marsh vegetation phenology and indicate that the different influences of climatic variation on marsh vegetation phenology in different regions should be fully considered to assess the marsh ecosystem response to climatic change in Sanjiang Plain. [ABSTRACT FROM AUTHOR]

Sanjiang Plain is the most extensive marsh distribution region in China. Marshes in this region can protect biodiversity, regulate climate, and provide habitats for wild animals and plants. The normalized difference vegetation index (NDVI) is a crucial indicator of vegetation coverage, which may reflect ecosystem structure and functional features. Clarifying the spatiotemporal change of marsh coverage and its climatic drivers is vital for observing and predicting vegetation change in Sanjiang Plain. Using meteorological dataand MODIS NDVI data from 2000 to 2020, we analyzed the spatiotemporal variation in marsh vegetation coverage and climatic change effects in Sanjiang Plain. We found that the growing season vegetation NDVI of marsh increased significantly at a rate of 0.011/decade, indicating that the marsh vegetation growth has obviously improved during the past 21 years. Furthermore, we found that the increase of minimum (Tmin) and maximum (Tmax) temperature in July can significantly promote the marsh plant growth, and increasing nighttime Tmin has a stronger impact on promoting the growth than increasing daytime Tmax in this month. In addition, the increase of daytime Tmax in August can promote the marsh vegetation growth, whereas the increasing precipitation in August was unfavorable for the growth in Sanjiang Plain. [ABSTRACT FROM AUTHOR]

Herbaceous marsh is the most widely distributed type of marsh wetland ecosystem, and has important ecological functions such as water conservation, climate regulation, carbon storage and fixation, and sheltering rare species. The carbon sequestration function of herbaceous marsh plays a key role in slowing climate warming and maintaining regional environmental stability. Vegetation biomass is an important index reflecting the carbon sequestration capacity of wetlands. Investigating the biomass of marsh vegetation can provide a scientific basis for estimating the carbon storage and carbon sequestration capacity of marshes. Based on field survey data of aboveground biomass of herbaceous marsh vegetation and the distribution data set of marsh in China, we analyzed the aboveground biomass and its spatial distribution pattern of herbaceous marsh on a national scale for the first time. The results showed that in China the total area of herbaceous marsh was 9.7×104 km2, the average density of aboveground biomass of herbaceous marsh vegetation was 227.5±23.0 g C m−2 (95% confidence interval, the same below), and the total aboveground biomass was 22.2±2.2 Tg C (1 Tg=1012 g). The aboveground biomass density of herbaceous marsh vegetation is generally low in Northeast China and the Tibetan Plateau, and high in central North China and coastal regions in China. In different marsh distribution regions of China, the average biomass density of herbaceous marsh vegetation from small to large was as follows: temperate humid and semi-humid marsh region (182.3±49.3 g C m−2)

Background: Climate change is predicted to lead to changes in the amount and distribution of precipitation during the growing seasonal. This "repackaging" of rainfall could be particularly important for grassland productivity. Here, we designed a two-factor full factorial experiment (three levels of precipitation amount and six levels of dry intervals) to investigate the effect of precipitation patterns on biomass production in Leymus chinensis (Trin.) Tzvel. (a dominant species in the Eastern Eurasian Steppe). Results: Our results showed that increased amounts of rainfall with prolonged dry intervals promoted biomass production in L. chinensis by increasing soil moisture, except for the longest dry interval (21 days). However, prolonged dry intervals with increased amount of precipitation per event decreased the available soil nitrogen content, especially the soil NO3−-N content. For small with more frequent rainfall events pattern, L. chinensis biomass decreased due to smaller plant size (plant height) and fewer ramets. Under large quantities of rain falling during a few events, the reduction in biomass was not only affected by decreasing plant individual size and lower ramet number but also by withering of aboveground parts, which resulted from both lower soil water content and lower NO3−-N content. Conclusion: Our study suggests that prolonged dry intervals between rainfall combined with large precipitation events will dramatically change grassland productivity in the future. For certain combinations of prolonged dry intervals and increased amounts of intervening rainfall, semi-arid grassland productivity may improve. However, this rainfall pattern may accelerate the loss of available soil nitrogen. Under extremely prolonged dry intervals, the periods between precipitation events exceeded the soil moisture recharge interval, the available soil moisture became fully depleted, and plant growth ceased. This implies that changes in the seasonal distribution of rainfall due to climate change could have a major impact on grassland productivity. [ABSTRACT FROM AUTHOR]

China has the third largest area of marshland in the world. Due to the effects of human activities, marshland in China has been widely converted to built‐up land (BL) and cultivated land (CL) during the past decades. Using satellite measurements of land surface temperature (LST), this study investigated the biophysical effects of marshland loss on LST. The results showed that marshland conversion to BL could increase the LST during both the daytime and nighttime. Conversion from marshland to CL could increase the daytime LST in most months and nighttime LST in the nongrowing season but decrease the daytime LST from July to September and nighttime LST in the growing season. Conversion from marshland to paddy field and dry farmland had different effects on LST. These complex effects suggest that the biophysical effects of marshland conversions should be considered in evaluating the effects of marshland loss on climate change in China. Key Points: Marshland conversion to built‐up land increases both daytime and nighttime land surface temperature (LST)Marshland conversion to cultivated land decreases the daytime LST from July to September and nighttime LST in the growing seasonConversion from marshland to paddy field and dry farmland has distinct effects on LST [ABSTRACT FROM AUTHOR]

Abstract Understanding wetland vegetation phenology and its response to climate change is important to predict the changes of wetland vegetation in wetland regions. Using the NDVI and climate data, this work studied the spatiotemporal change of start date of vegetation growing season (SOS) and explored the possible effects of climate change on the SOS over freshwater marshes of Northeast China. The results showed that the SOS significantly advanced by 0.52 day per year throughout the freshwater marshes of Northeast China during 2001 to 2016. The significant advancing of SOS was mainly concentrated in freshwater marshes of the Khingan Mountains (the Greater Khingan Mountains and the Lesser Khingan Mountains) and central arid or semi-arid regions (Songnen plain and Liaohe plain) in Northeast China. By contrast, there were weak delay trends of SOS in freshwater marshes of Eastern Inner Mongolia region, and Sanjiang plain. We found that precipitation was a dominant factor determining the SOS in arid or semi-arid regions (Songnen plain and Liaohe plain), while temperature played a bigger role in determining the SOS in Sanjiang plain and three cold mountains of the Northeast China. During the study period, increasing precipitation in the winter and spring contributed to advancing SOS in Songnen plain and Liaohe plain; the decrease of temperature from December to April explain the delaying SOS in freshwater marshes of Sanjiang Plain; the weak warming of temperature between November and May account for the advancing SOS of freshwater marshes in three cold mountains. In freshwater marshes of cold and the most arid region of Northeast China (Eastern Inner Mongolia), the SOS was influenced by both precipitation and temperature. Decreasing precipitation between January and April, as well as temperature decreases in March and April explain the delay of SOS in freshwater marshes of Eastern Inner Mongolia region. Graphical abstract Unlabelled Image Highlights • The start of the growing season (SOS) obviously advanced in most freshwater marshes. • The effects of climate change on SOS are different among ecological function regions. • Precipitation and temperature determines SOS in arid and cold regions, respectively. [ABSTRACT FROM AUTHOR]

Understanding the spring phenology of temperate grasslands and its response to climate change are crucial for diagnosing the responses of ecosystem to regional climate change and projecting regional ecosystem carbon exchange. Using NDVI data from 1982 to 2015, this study investigated the changes of the start date of the vegetation growing season (SOS) for the temperate grasslands of China, and explored the possible effects of average monthly T max , T min and total precipitation on the SOS across different grassland vegetation types. We improved on prior studies of climate change in China’s temperate zone by focusing only on grasslands unchanged over this extended study period. The results showed that the SOS significantly advanced at a rate of 1.84 days/decade from 1982 to 2015, controlled mainly by spring precipitation and spring and winter temperatures, with differing degrees of influence among vegetation types. On average, an increase of 10 mm in spring precipitation would advance SOS by 1.7 days across the temperate grasslands of China. Although warmer temperatures generally led to advanced SOS, this study revealed for the first time that the seasonal effects of daytime and nighttime warming on the SOS of temperate grasslands in China were asymmetric, with T max more influential in winter and T min more influential in spring. An increase of 1 °C in winter T max and spring T min would advance SOS by 0.42 and 1.34 days, respectively, compared with effects of 0.24 or 0.64 days for 1 °C increases in winter T min or spring T max . Given the global asymmetry in daytime and nighttime warming, this study highlights the asymmetric effects of daytime and nighttime warming on the SOS of temperate grasslands in China, and suggests that the impacts of seasonal T max and T min should be considered separately in the SOS modules of terrestrial ecosystem models for temperate grasslands. [ABSTRACT FROM AUTHOR]

Based on daily maximum and minimum temperature data from 437 weather stations over China, this study examined the spatiotemporal change of temperature extremes in China from 1960 to 2011. Results showed a general downward trends in the occurrence of cold days (TX10) and nights (TN10) (base period 1961-1990), but upward tendency on the occurrence of warm days (TX90) and nights (TN90), the temperatures of coldest day (TXn), coldest night (TNn), warmest day (TXx), and warmest night (TNx) in China and most climate regions. At the national scale, TX10 and TN10 have significantly decreased by −1.89 and −4.39 days/decade, and TX90 and TN90 have significantly increased by 2.49 and 4.72 days/decade from 1960 to 2011. The national average trends for TXn, TNn, TXx, and TNx were 0.28, 0.54, 0.17, and 0.27 °C/decade, respectively. The temporal changes of extremes indices showed that changes in cold (warm) relative indices may be primarily related to that of corresponding winter (summer) T and T, respectively. Regionally, the magnitudes of changes in extreme indices decreased from the north to south of China. However, we found significant increase of warm extremes, especially warm days and nights in Southeast China. For most climate regions, the trend magnitudes in warm days/nights were larger than that in cold days/nights, but the trend in coldest temperature was much higher than that in warmest temperature. The trend magnitudes in minimum temperature indices were larger than those based on daily maximum temperature, explaining the faster increase of T than T in China. [ABSTRACT FROM AUTHOR]

As a fragile ecological zone, the temperate grassland region of China has experienced dramatic land use/land cover (LULC) changes due to human disturbances. So far, the impacts of LULC change on climate especially the diurnal temperature range (DTR) in this region are still not well understood. Based on the OMR (observation minus reanalysis) method, this study investigated the effects of LULC on DTR in the temperate grassland region of China. Considering the possible uncertainty of the results due to spatial resolution of the reanalysis dataset, two reanalysis datasets with different spatial resolutions were utilized. Results showed that LULC generally contributed to the decline of DTR in the temperate grassland region of China during 1980 to 2005. Due to different warming effects on monthly maximum temperature (Tmax) and minimum temperature (Tmin), grassland and forest tend to slightly decrease monthly DTR (approximately − 0.053 to − 0.050 °C/decade and approximately − 0.059 to − 0.055 °C/decade, respectively), while bare land has a slightly positive effect on DTR (approximately 0.018–0.021 °C/decade). By contrast, cropland and urban tend to slightly decrease Tmax, obviously increase Tmin and thus result in a rapid decline of DTR (approximately − 0.556 to − 0.503 °C/decade and approximately − 0.617 to − 0.612 °C/decade, respectively). In the temperate grassland region of China, grassland vegetation changes due to human disturbances can have some effects on DTR mainly by changing the Tmax. Conversion from grassland to cropland could decrease the DTR by slowing down the increase of Tmax. But the conversion from grassland to bare land, as well as the reduction of grassland vegetation cover will increase Tmax, and consequently the DTR. The results suggest that grassland degradation is likely to result in daylight warming and increased DTR in the temperate grassland region of China. [ABSTRACT FROM AUTHOR]

Based on the observation minus reanalysis (OMR) method, this study explored the impacts of grassland vegetation on diurnal temperature range (DTR) in China’s temperate grassland region from 1982 to 2005. Results showed that temperate grassland vegetation generally tended to decrease growing-season DTR, but the degree of influence of vegetation on DTR was different among different grassland types. From 1982 to 2005, the decline of OMR trend in growing-season DTR was the largest for temperate meadow (−0.191 °C/decade), moderate for temperate steppe (−0.093 °C/decade) and the smallest for temperate desert steppe (−0.022 °C/decade). During the whole growing season, grassland vegetation has a similar warming effect on minimum air temperature (T min ), and the differences in monthly OMR trends of DTR are mainly determined by the effects of vegetation on maximum air temperature (T max ). For temperate meadow and temperate steppe, there were obvious cooling effects of vegetation on T max from July to September due to evaporative cooling feedback, and these cooling effects intensified with the increase of surface vegetation greenness. For temperate desert steppe, due to low vegetation cover and weak cooling feedback, it exerted comparable warming effects on T max and T min , thus having no significant impact on DTR change in any month. [ABSTRACT FROM AUTHOR]

The sensitivity of surface air temperature response to different grassland types and vegetation cover changes in the regions of temperate grassland of China was analyzed by observation minus reanalysis (OMR) method. The basis of the OMR approach is that reanalysis data are insensitive to local surface properties, so the temperature differences between surface observations and reanalysis can be attributed to land effects. Results showed that growing-season air temperature increased by 0.592 °C/decade in the regions of temperate grassland of China, with about 31 % of observed warming associated with the effects of grassland types and vegetation cover changes. For different grassland types, the growing-season OMR trend was the strongest for temperate desert steppe (0.259 °C/decade) and the weakest for temperate meadow (0.114 °C/decade). Our results suggest that the stronger intraseasonal changes of grassland vegetation are present, the more sensitive the OMR trend responds to the intraseasonal vegetation cover changes. In August and September, the OMR of temperate meadow showed a weak cooling trend. For temperate meadow, about 72.2 and 72.6 % of surface cooling were explained by both grassland type and increase of vegetation cover for August and September, respectively. For temperate steppe and temperate desert steppe, due to the limited soil moisture and little evaporative cooling feedback, the vegetation changes have no significant effect on the surface air temperature. These results indicate that the impact of grassland types and vegetation cover changes should be considered when projecting further climate change in the temperate grassland region of China. [ABSTRACT FROM AUTHOR]

Exploring the impacts of vegetation cover on regional climate is very important to assess the relationship between vegetation and climate, and to predict regional climate change in vegetated areas. Using the time series of Global Inventory Modelling and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI), we estimated the impacts of grassland vegetation cover on surface air temperatures based on the observation minus reanalysis (OMR) approach. The theory of the OMR approach is that reanalysis data are not sensitive to local land surface properties, thus the changes in OMR can be attributed to land effects. The method used in this letter is that rates of change in OMR are regressed (using stepwise regression) on average NDVI and the rate of NDVI change. We applied this multiple stepwise regression analysis in the temperate grassland region of China during the growing season from 1982 to 2005. To evaluate the accuracy of regress equations, we estimated the monthly OMR temperatures during 1983–2005 and then compared the monthly estimated and actual OMR temperatures. The results showed that the estimated OMR temperatures were well consistent with actual OMR temperatures in all the months, with the correlation coefficients between them ranging from 0.83 to 0.98. It indicates that combined with the OMR approach, GIMMS NDVI can be used to accurately estimate the impacts of grassland vegetation on surface air temperatures in temperate grassland areas of China. [ABSTRACT FROM PUBLISHER]

• Effect of shrub encroachment on land surface temperature (LST) was quantified. • Shrub encroachment warms the LST in most northern temperate semi-arid regions. • Shrub encroachment cools the LST in southwest North America and Central Asia. Under the influences of climate change and human activities, grassland ecosystems are being invaded by shrubs around the world, especially in temperate semi-arid regions of the Northern Hemisphere. Shrub encroachment can not only affect the properties of grassland ecosystem, but also have an important impact on regional or global climate by affecting biogeochemical and biophysical processes. Although shrub encroachment has become a serious ecological problem in the northern temperate region during the past decades, the possible effects of shrub encroachment on regional climate in northern temperate grasslands remain unclear due to a lack of in situ and long-term environmental records. Based on the satellite-derived land use data, land surface temperature (LST), evapotranspiration, leaf area index, and albedo data, this study quantified, for the first time, the biophysical effects of shrub encroachment on regional climate in semi-arid areas of temperate regions of the Northern Hemisphere. The results indicate that shrub encroachment tends to increase the average annual daytime and mean LST in most of the northern temperate semi-arid region due to increased bare soil fraction. In contrast, shrub encroachment could decrease the daytime LST in relatively humid region of southwest of North America by increasing evapotranspiration (vegetation coverage) and decreasing bare soil fraction. In the arid center region of Central Asia, grassland conversion to shrubland slightly decreases the surface temperature during both daytime and nighttime due to increased albedo caused by decreasing soil water content. Our findings imply that the biophysical effects of shrub encroachment on regional climate should be considered in climate models if they are to accurately simulate climate change in temperate regions of the Northern Hemisphere. More attention should be paid to the climate feedbacks of shrub encroachment, especially considering the distinct effects in different regions and how these climate feedbacks are likely to further impact ecosystem properties. [ABSTRACT FROM AUTHOR]

• The net primary productivity (NPP) significantly increased in marshes of study area. • Summer daytime and nighttime temperatures had an asymmetric effect on marsh NPP. • Increased precipitation in summer and autumn can enhance the NPP of marsh vegetation. The western Songnen Plain has a large area of marshes that are able to modulate the regional carbon cycle. Net primary productivity (NPP) is an important ecological indicator of carbon storage within the marsh ecosystems. Although climate change could have significantly changed marsh vegetation NPP during the past decades, the spatiotemporal variation in marsh vegetation NPP and how climate change affects marsh vegetation NPP remain unclear in the western Songnen Plain. In this paper, we assessed the spatiotemporal variation in the NPP of marshes at the western Songnen Plain and evaluated its response to climate change from 2000 to 2020. The NPP of marshes over the western Songnen Plain increased significantly at a rate of 5.69 g C/m2/a during 2000 to 2020, with an average value of about 273.62 g C/m2/a. The largest increase of the NPP of marshes was mainly distributed in the northwest part of the Songnen Plain. Correlation analysis results showed that the increased precipitation in summer and autumn could enhance the NPP of marsh vegetation. By contrast, the increase of mean temperature in summer reduced the NPP of marshes. In addition, we first found the asymmetric impacts of summer minimum temperature (T min) and maximum temperature (T max) on marsh vegetation NPP. Notably, the increase in summer T max could significantly reduce NPP, while the increase in T min could increase NPP. Under the background of global asymmetric warming of daytime and nighttime temperatures, more attention should be paid to the different effects of T max and T min on marsh NPP in the western Sonegnen Plain. The findings of this study can provide theoretical guidance for ecological protection and the adaptive management of marsh vegetation at the western Songnen Plain. [ABSTRACT FROM AUTHOR]

Based on GIMMS NDVI and climate data from 1982 to 2006, this study analyzed the impact of climate change on grassland in China. During the growing season, there were significant effects of precipitation on the growth of all the grassland types (P<0.05), except for meadow vegetation. For the air temperatures, there existed asymmetrical effects of maximum temperature (Tmax) and minimum temperature (Tmin) on grassland vegetation, especially for the temperate grasslands and alpine steppe. The growing season NDVI correlated negatively with Tmax but positively with Tmin for temperate grasslands. Seasonally, these opposite effects were only observed in summer. For alpine steppe, the growing season NDVI correlated positively with Tmax but negatively with Tmin, and this pattern of asymmetrical responses was only obvious in spring and autumn. Under the background of global asymmetric warming, more attention should be paid to this asymmetric response of grassland vegetation to daytime and night-time warming, especially when we want to predict the productivity of China’s grasslands in the future. [ABSTRACT FROM AUTHOR]

We compare Bayesian and sample theory model specification criteria. For the Bayesian criteria we use the deviance information criterion and the cumulative density of the mean squared errors of forecast. For the sample theory criterion we use the conditional Kolmogorov test. We use Markov chain Monte Carlo methods to obtain the Bayesian criteria and bootstrap sampling to obtain the conditional Kolmogorov test. Two non nested models we consider are the CIR and Vasicek models for spot asset prices. Monte Carlo experiments show that the DIC performs better than the cumulative density of the mean squared errors of forecast and the CKT. According to the DIC and the mean squared errors of forecast, the CIR model explains the daily data on uncollateralized Japanese call rate from January 1, 1990 to April 18, 1996; but according to the CKT, neither the CIR nor Vasicek models explains the daily data. [ABSTRACT FROM AUTHOR]

The diurnal temperature range (DTR) is considered a signature of observed climate change, which is defined as the difference between the maximum (Tmax) and minimum temperatures (Tmin). It is well known that the warming rate of mean temperature is larger at high elevations than at low elevations in northeast China. However, it is still uncertain whether DTR trend is greater at high elevations. This study examined the spatiotemporal variation in DTR and its relationship with elevation in northeast China based on data from 68 meteorological stations from 1961 to 2015. The results show that there was a significant declining trend (0.252 °C/decade) in DTR from 1961 to 2015 due to the fact that Tmin increased at a faster rate than Tmax. Seasonally, DTR in northeast China showed a decreasing trend with the largest decrease rate in spring (−0.3167 °C/decade) and the smallest decrease rate in summer (−0.1725 °C/decade). The results of correlation analysis show that there was a significant positive correlation between the annual DTR trend and elevation in northeast China. This is due to the fact that increasing elevation has a significant warming effect on Tmax. Seasonally, there were significant positive correlations between the DTR trend and elevation in all seasons. The elevation gradient of DTR trend was the greatest in winter (0.392 °C/decade/km) and the lowest in autumn (0.209 °C/decade/km). In spring, summer, and autumn, increasing elevation has a significant warming effect on Tmax, leading to a significant increase of the DTR trend with increasing elevation. However, in winter, increasing elevation has a significant cooling effect on Tmin, resulting in a significant increase of the DTR trend with increasing elevation. [ABSTRACT FROM AUTHOR]

The vegetation coverage of temperate grasslands in China has changed substantially due to climate change during the past decades, which significantly affects the function of grassland ecosystems. To appropriately carry out adaptive management and protect temperate grassland vegetation, it is important to understand the variations in fractional vegetation coverage (FVC) of China's temperate grasslands and how they are responding to climate change. Using the GIMMS NDVI and climatic datasets, this study explored the dynamics of FVC and their climatic drivers across the temperate grassland region of China during 1982∼2015. The results showed that the growing season mean FVC increased by 0.12% per year during 1982∼2015. The increases in precipitation and minimum temperature in the growing-season (especially in spring) could enhance the FVC of various vegetation types. In summer, the FVC of temperate steppe and desert steppe could drastically increase with increasing precipitation. In addition, this study found that the impacts of daytime and night-time warming on the FVC of temperate grasslands were asymmetric. Daytime warming can moderately increase FVC of temperate grasslands, while night-time warming could significantly increase it. Furthermore, the increase in summer daytime and night-time temperatures leads to a weak decrease and a moderate increase in FVC, respectively. This asymmetric effect was more evident for the temperate steppe and desert steppe in the central area. In autumn, the temperatures increase had significant positive impacts on the FVC of temperate meadows and steppes. This study highlights the differences in the impacts of climate change at different time scales on the FVC of grasslands with various vegetation types, and indicates that the asymmetric influences of daytime and night-time temperatures in different seasons on FVC must be included in calculating the vegetation coverage of China's temperate grasslands. The results could provide information for maintaining grassland ecosystem functions and managing environmental systems. • The FVC of temperate grasslands has increased by 0.12% per year from 1982 to 2015. • Increases in growing season precipitation and minimum temperature enhanced the FVC. • Nighttime and daytime temperatures have asymmetric effects on the FVC. [ABSTRACT FROM AUTHOR]

Using a bottom-up estimation method, a comprehensive, high-resolution emission inventory of gaseous and particulate atmospheric pollutants for multiple anthropogenic sectors with typical local sources has been developed for the Harbin-Changchun city agglomeration (HCA). The annual emissions for CO, NO x , SO 2 , NH 3 , VOC S , PM 2.5 , PM 10 , BC and OC during 2017 in the HCA were estimated to be 5.82 Tg, 0.70 Tg, 0.34 Tg, 0.75 Tg, 0.81Tg, 0.67 Tg, 1.59 Tg, 0.12 Tg and 0.26 Tg, respectively. For PM 10 and SO 2 , the emissions from industry processes were the dominant contributors representing 54.7% and 49.5%, respectively, of the total emissions, while 95.3% and 44.5% of the total NH 3 and NO x emissions, respectively, were from or associated with agricultural activities and transportation. Spatiotemporal distributions showed that most emissions (except NH 3) occurred in November to March and were concentrated in the central cities of Changchun and Harbin and the surrounding cities. Open burning of straw made an important contribution to PM 2.5 in the central regions of the northeastern plain during autumn and spring, while domestic coal combustion for heating purposes was significant with respect to SO 2 and PM 2.5 emissions during autumn and winter. Furthermore, based on Principal Component Analysis and Multivariable Linear Regression model, air temperature, relative humidity, electricity and energy consumption, and the urban and rural population were optimized to be representative indicators for rapidly assessing the magnitude of regional atmospheric pollutants in the HCA. Such indicators and equations were demonstrated to be useful for local atmospheric environment management. [Display omitted] Using a bottom-up estimation method, a comprehensive, high-resolution emission inventory of gaseous and particulate atmospheric pollutants for multiple anthropogenic sectors with typical local sources (e.g., biomass burning, domestic coal combustion and cooking) has been developed for this region. The annual emissions for CO, NO x , SO 2 , NH 3 , VOC S , PM 2.5 , PM 10 , BC and OC during 2017 in the HCA were estimated to be 5.82 Tg, 0.70 Tg, 0.34 Tg, 0.75 Tg, 0.81Tg, 0.67 Tg, 1.59 Tg, 0.12 Tg and 0.26 Tg, respectively. For PM 10 and SO 2 , the emissions from industry processes (INP) were the dominant contributors representing 54.7% and 49.5%, respectively, of the total emissions, while 95.3% and 44.5% of the total NH 3 and NOx emissions, respectively, were from or associated with agricultural activities (AGR) and transportation (TRP). Spatiotemporal distributions showed that most emissions (except NH 3) occurred in November to March and were concentrated in the central cities of Changchun and Harbin and the surrounding cities. Open burning of straw made an important contribution to PM 2.5 in the central regions of the northeastern plain during autumn and spring (i.e., October, November, March and April), while domestic coal combustion for heating purposes was significant with respect to SO 2 and PM 2.5 emissions during autumn and winter, thus suggesting SO 2 and PM 2.5 emissions were the dominant sources or sub-sources in the HCA. Furthermore, based on Principal Component Analysis (PCA) and Multivariable Linear Regression (MLR) model, the air temperature, the relative humidity, electricity and energy consumption, and the urban and rural population were optimized to be representative indicators for rapidly assessing the magnitude of regional atmospheric pollutants in the HCA. Such indicators and equations were demonstrated to be useful for local atmospheric environment management and for numeral simulation of air quality. [ABSTRACT FROM AUTHOR]

Extreme precipitation response to increasing temperature includes not only changes of frequency and intensity, but also changes of extreme precipitation interval (EPIV) and the precipitation during the neighboring daily extreme precipitations interval (EPIP). These changes have not been fully evaluated yet in observations or climate model simulations although they are very useful to understand variations of extreme precipitation. We used daily precipitation data from 669 meteorological stations during the past five decades across China and projections of 19 general circulation models from CMIP5 under the RCP4.5 and RCP8.5 scenarios to investigate variations of EPIV and EPIP. We found the national average annual EPIV increased across China during the last five decades, while annual EPIP significantly decreased. The decreases mainly occurred in southwest China, east China, and southeast China. At national and regional scales, the average annual EPIV and EPIP showed greater decreases under the RCP8.5 scenario than those under the RCP4.5 scenario from 2006 to 2100. Annual EPIP showed a stronger correlation with extreme precipitation intensity than EPIV. The national average annual EPIP had a significant positive correlation with the Western Pacific Subtropical High Area Index. The abnormal geopotential heights over western Mongolia and the western Pacific at 500 hpa as well as the abnormal SSTs in Japan Sea and the western of Pacific in rainy seasons would result in abnormal annual EPIVs and EPIPs in China. This study may provide references for flooding prediction, water resources management, and disaster prevention and mitigation. [ABSTRACT FROM AUTHOR]

This study investigated the recent and future spatiotemporal changes in summer hot days (HDs) and heat waves (HWs) and their relationships with large‐scale atmospheric circulations over Northeast China (NEC). We used daily maximum temperature data from 109 meteorological stations for the period 1961–2013 across NEC and the output of 11 general circulation models from Coupled Model Intercomparison Project Phase 5 under RCP4.5 and RCP8.5 emission scenarios. We found that the frequencies and intensities of summer HDs and HWs overall increased in the last 53 years. The increases mainly occurred in the northeastern Inner Mongolia, the north part of the Heilongjiang Province, and southern Changbai Mountains. The during time periods between the start and end dates of HDs were lengthened from 1961 to 2013 in the eastern Inner Mongolia, the northeastern Heilongjiang Province, and the southern Liaoning Province. Our results showed that HDs and HWs exhibited significant increasing trends from 2006 to 2100 under RCP4.5 and RCP8.5 emission scenarios. Generally, more frequent and intense summer HDs and HWs would happen in NEC over the 21st century. Especially, the northwest of NEC and the south and middle of Da Hinggan Mountains would experience the most frequent and intense HDs and HWs. The variations in atmospheric circulation in summers with abnormal frequency of HDs and HWs were driven by Asian Zonal Circulation and Western Pacific Subtropical High simultaneously. An anticyclonic circulation anomaly prevailing over the west of NEC and the higher summer surface sea temperature in Japan Sea resulted in more frequent HDs and HWs across NEC. This study may help to understand future changes in HDs and HWs and provide references for water resources management and policy‐making in agriculture and forestry. The frequencies and intensities of summer hot days (HDs) and heat waves (HWs) all showed increasing trends across Northeast China (NEC) for the past five decades. More frequent and intense summer HDs and HWs would occur in the future over NEC. An anticyclonic circulation anomaly prevailing over the west of NEC and the higher summer SST in Japan Sea resulted in more frequent HDs and HWs across NEC. [ABSTRACT FROM AUTHOR]

ABSTRACT: We report on changes in annual decile groups of daily maximum and minimum temperatures (Tmax and Tmin) from 437 weather stations across China since 1955, with special attention to the reported global warming ‘hiatus’ period since 1999. The values of Tmax and Tmin have increased significantly across all deciles between 1955 and 2014, with colder deciles of Tmin increasing faster than warmer deciles. We find abrupt increases starting at colder deciles since the early 1970s for Tmin and mid‐1980s for Tmax, followed by increases in the middle deciles in the later 1980s and in the warmer deciles in the early 1990s for both Tmax and Tmin. During the warming hiatus period, in contrast to the prior rapid warming period, colder deciles show no significant decreasing trends, while most middle to warmer deciles of Tmin continue to increase significantly, a finding which is masked in studies focusing on either average temperatures or extremes. The recent pause in the increase of mean temperatures is probably due to opposing changes in the trends at the tails of the temperature distribution. Our results demonstrate the differential changes in class intervals across the entire distribution of daily maximum and minimum temperatures. [ABSTRACT FROM AUTHOR]

ABSTRACT We analysed observations of daily maximum and minimum air and soil surface temperatures collected between 1965 and 2007 in the temperate steppe region of North China to understand the climatology and trends of the diurnal temperature range. Sunshine duration and precipitation records were also analysed for their relationships with the changes in temperatures. In general, the daily maximum soil surface temperatures ( SSTmax) are generally much higher than the daily maximum air temperature (Tmax), and the daily minimum soil surface temperature ( SSTmin) are slightly lower than the daily minimum air temperature (Tmin) throughout the year. Consequently, the soil surface diurnal temperature range ( SSDTR) is much higher than diurnal temperature range of air temperatures ( DTR). As with air temperatures, soil surface temperatures have warmed significantly over the study period at most stations, increasing by 0.62 °C per decade for SSTmax and 0.64 °C per decade for SSTmin for the region overall. Annual and seasonal SSTmax and SSTmin have increased faster than Tmax and Tmin, except for SSTmax in winter. Declines in air DTR have been commonly observed, but in our study SSDTR decreases only in winter, driven by a steep decline after 2000, mostly resulting from strong increases in SSTmin and slight decreases in SSTmax. Both annual and seasonal calculations indicate that the decline in air DTR mainly coincided with a period of rapid decrease in sunshine duration before 1990. Total cloud amount decreased during this period, so the changes in total cloud amount could not be the cause for decrease in sunshine duration and DTR before 1990. SSDTR shows a different pattern: the rapid decrease of SSDTR in winter season since the end of 1990 coincides with a decrease in sunshine duration and an increase in total cloud amount, which may have contributed to the decrease in winter SSDTR in the new millennium. [ABSTRACT FROM AUTHOR]