In this study, based on daily gage precipitation data of 2480 stations from 1961 to 2016, the summer (JuneeAugust) extreme precipitationevent was defined using the 95th percentile, and the changes in persistent (la...In this study, based on daily gage precipitation data of 2480 stations from 1961 to 2016, the summer (JuneeAugust) extreme precipitationevent was defined using the 95th percentile, and the changes in persistent (last for at least 2 d) and non-persistent (1 d) extreme precipitation inChina were analyzed. The results indicate that under global warming, the contribution of extreme precipitation to total summer precipitationincreased in most areas of China, but it decreased in the central part of Inner Mongolia and the Sichuan Basin. In North and Southwest China,both persistent and non-persistent extreme precipitation decreased; the decreasing trend of persistent extreme precipitation was more prominent;thus, extreme precipitation event occurred more as non-persistent event. Meanwhile, in the Yangtze River Basin and South China, both types ofextreme precipitation increased particularly the persistent extreme precipitation; persistent extreme precipitation occurred more compared withnon-persistent events.展开更多
In this paper, based on hourly precipitation observations in 1977e2013 in the Beijing area, China, hourly precipitation in summer (June?August) is classified into three categories: light (below the 50th percentile val...In this paper, based on hourly precipitation observations in 1977e2013 in the Beijing area, China, hourly precipitation in summer (June?August) is classified into three categories: light (below the 50th percentile values), moderate (the 50th to 95th percentile values), and heavy (above the 95th percentile values). Results reveal that both light and moderate precipitation decreased significantly during the research period and thereby caused the decrease in summer totals. By contrast, pronounced trends failed to be detected in the heavy category. Since 2004, the contribution of heavy rainfall to the summer total precipitation in the urban area increased as compared to the suburban area, which is opposite to light rainfall. There are obvious differences in the diurnal variations of classified precipitation. Light precipitation shows a double peak structure in the early morning and at night, while moderate and heavy rainfall show a single peak at night. Light precipitation at the early morning peak time decreased significantly in the whole Beijing area. Compared with the suburban area, light precipitation in the urban area occurred less frequently whereas heavy precipitation occurred more frequently at evening peak time after 2004. The asymmetry of the rainfall is obvious, especially, for heavy precipitation. The asymmetry of heavy precipitation events in the urban area exhibits a significant increasing trend.展开更多
Recently,a hot topic about warmer and wetter climate change in the arid region of Northwest China,especially in Xinjiang,has attracted much attention by general public and scientific community.This study revisits this...Recently,a hot topic about warmer and wetter climate change in the arid region of Northwest China,especially in Xinjiang,has attracted much attention by general public and scientific community.This study revisits this topic especially for Xinjiang in the Eurasian continental context from multiple perspectives based on most updated CRU high-resolution grid data and China's homogenized station data in 1961–2019.We conclude that such‘warming-wetting’trend is not a regional phenomenon for Xinjiang but has much larger spatial scale.Regions having experienced both temperature and precipitation increases reflecting‘warming-wetting’trend account for more than half of the Eurasian continent since 1961.Nevertheless,the‘warming-wetting’trend in Xinjiang suggests some unique regional features in response to the global warming.Although drought seems to have relieved to some extent,especially in the mountainous regions in western Xinjiang,the nature of arid and semi-arid climate regime has not changed.Noticeably,the interannual variability of precipitation has enlarged and the increase in extreme precipitation events has a major contribution.These findings suggest that‘warming-wetting’trend in Xinjiang is asymmetric regarding warming and wetting in seasons and intensifying interannual variability and increasing contribution of extreme precipitation to the total.Thus,the current‘warming-wetting’trend in Xinjiang possibly brings us some beneficial impacts for the ecosystem but also increases challenges for water resources utilization and risk management.展开更多
The concept of carbon neutrality is much emphasized in IPCC Spatial Report on Global Warming of 1.5C in order to achieve the long-termtemperature goals as reflected in Paris Agreement.To keep these goals within reach,...The concept of carbon neutrality is much emphasized in IPCC Spatial Report on Global Warming of 1.5C in order to achieve the long-termtemperature goals as reflected in Paris Agreement.To keep these goals within reach,peaking the global carbon emissions as soon as possible andachieving carbon neutrality are urgently needed.However,global CO_(2)emissions continued to grow up to a record high of 43.1 Gt CO_(2)during2019,with fossil CO_(2)emissions of 36.5 Gt CO_(2)and land-use change emissions of 6.6 Gt CO_(2).In such case,the global carbon emissions mustdrop 32 Gt CO_(2)(7.6%per year)from 2020 to 2030 for the 1.5C warming limit,which is even larger than the COVID-induced reduction(6.4%)in global CO_(2)emissions during 2020.Recently,China has announced scaling up its national commitments,aiming to peak its CO_(2)emissionsbefore 2030 and achieve carbon neutrality before 2060.Achieving these goals requires rapid and far-reaching transitions in the whole society.Onthe one hand,deeper emissions reduction in all sectors includes decarbonization of energy,electrification,increasing share of renewables,energyefficiency,sustainable land management,decarbonization of transport,reducing food loss and waste,as well as behavior and lifestyles changes.On the other hand,possible actions by removing CO_(2)from the atmosphere involves enlarging land and ocean net carbon sink,CO_(2)removaltechnologies(such as Bioenergy with carbon capture and storage),and CO_(2)capture,utilization and storage technologies,but should be cautionfor their scales and tradeoffs.展开更多
Understanding climate change as well as its impacts on vegetation growth over the Tibetan Plateau has important implication for ecosystems.This study investigated changes in drought conditions and their impacts on veg...Understanding climate change as well as its impacts on vegetation growth over the Tibetan Plateau has important implication for ecosystems.This study investigated changes in drought conditions and their impacts on vegetation growth over the Tibetan Plateau.The results reveal that the precipitation in growing season(May-September)shows a significant increase over most parts of the central and eastern Tibetan Plateau during 1961—2019.Consequently,drought conditions have generally relieved except in the south and northeast where precipitation has decreased.Combining analyses of gridded-dataset-derived drought indices with vegetation indices during 1982—2015,vegetation improvement in most regions of the Plateau is mainly due to lessened drought conditions.Noticeably,vegetation degradation is also found in part of southern Tibetan Plateau mainly resulting from drought enhancement.This study is expected to provide scientific basis for understanding of change in drought condition and its impacts on vegetation over different regions of TP under global warming background.展开更多
文摘In this study, based on daily gage precipitation data of 2480 stations from 1961 to 2016, the summer (JuneeAugust) extreme precipitationevent was defined using the 95th percentile, and the changes in persistent (last for at least 2 d) and non-persistent (1 d) extreme precipitation inChina were analyzed. The results indicate that under global warming, the contribution of extreme precipitation to total summer precipitationincreased in most areas of China, but it decreased in the central part of Inner Mongolia and the Sichuan Basin. In North and Southwest China,both persistent and non-persistent extreme precipitation decreased; the decreasing trend of persistent extreme precipitation was more prominent;thus, extreme precipitation event occurred more as non-persistent event. Meanwhile, in the Yangtze River Basin and South China, both types ofextreme precipitation increased particularly the persistent extreme precipitation; persistent extreme precipitation occurred more compared withnon-persistent events.
基金This work was supported by the National Natural Science Foundation of China (41575094) and Special Scientific Research Fund of Meteorological Public Welfare Profession of China (GYHY201506014).
文摘In this paper, based on hourly precipitation observations in 1977e2013 in the Beijing area, China, hourly precipitation in summer (June?August) is classified into three categories: light (below the 50th percentile values), moderate (the 50th to 95th percentile values), and heavy (above the 95th percentile values). Results reveal that both light and moderate precipitation decreased significantly during the research period and thereby caused the decrease in summer totals. By contrast, pronounced trends failed to be detected in the heavy category. Since 2004, the contribution of heavy rainfall to the summer total precipitation in the urban area increased as compared to the suburban area, which is opposite to light rainfall. There are obvious differences in the diurnal variations of classified precipitation. Light precipitation shows a double peak structure in the early morning and at night, while moderate and heavy rainfall show a single peak at night. Light precipitation at the early morning peak time decreased significantly in the whole Beijing area. Compared with the suburban area, light precipitation in the urban area occurred less frequently whereas heavy precipitation occurred more frequently at evening peak time after 2004. The asymmetry of the rainfall is obvious, especially, for heavy precipitation. The asymmetry of heavy precipitation events in the urban area exhibits a significant increasing trend.
基金supported by the National Key Research and Development Program of China(2018YFC1507700).
文摘Recently,a hot topic about warmer and wetter climate change in the arid region of Northwest China,especially in Xinjiang,has attracted much attention by general public and scientific community.This study revisits this topic especially for Xinjiang in the Eurasian continental context from multiple perspectives based on most updated CRU high-resolution grid data and China's homogenized station data in 1961–2019.We conclude that such‘warming-wetting’trend is not a regional phenomenon for Xinjiang but has much larger spatial scale.Regions having experienced both temperature and precipitation increases reflecting‘warming-wetting’trend account for more than half of the Eurasian continent since 1961.Nevertheless,the‘warming-wetting’trend in Xinjiang suggests some unique regional features in response to the global warming.Although drought seems to have relieved to some extent,especially in the mountainous regions in western Xinjiang,the nature of arid and semi-arid climate regime has not changed.Noticeably,the interannual variability of precipitation has enlarged and the increase in extreme precipitation events has a major contribution.These findings suggest that‘warming-wetting’trend in Xinjiang is asymmetric regarding warming and wetting in seasons and intensifying interannual variability and increasing contribution of extreme precipitation to the total.Thus,the current‘warming-wetting’trend in Xinjiang possibly brings us some beneficial impacts for the ecosystem but also increases challenges for water resources utilization and risk management.
基金the Basic Research to Operation Funds of the Chinese Academy of Meteorological Sciences(2020Y004)National Key Research and Development Program of China(2018YFC1507700).
文摘The concept of carbon neutrality is much emphasized in IPCC Spatial Report on Global Warming of 1.5C in order to achieve the long-termtemperature goals as reflected in Paris Agreement.To keep these goals within reach,peaking the global carbon emissions as soon as possible andachieving carbon neutrality are urgently needed.However,global CO_(2)emissions continued to grow up to a record high of 43.1 Gt CO_(2)during2019,with fossil CO_(2)emissions of 36.5 Gt CO_(2)and land-use change emissions of 6.6 Gt CO_(2).In such case,the global carbon emissions mustdrop 32 Gt CO_(2)(7.6%per year)from 2020 to 2030 for the 1.5C warming limit,which is even larger than the COVID-induced reduction(6.4%)in global CO_(2)emissions during 2020.Recently,China has announced scaling up its national commitments,aiming to peak its CO_(2)emissionsbefore 2030 and achieve carbon neutrality before 2060.Achieving these goals requires rapid and far-reaching transitions in the whole society.Onthe one hand,deeper emissions reduction in all sectors includes decarbonization of energy,electrification,increasing share of renewables,energyefficiency,sustainable land management,decarbonization of transport,reducing food loss and waste,as well as behavior and lifestyles changes.On the other hand,possible actions by removing CO_(2)from the atmosphere involves enlarging land and ocean net carbon sink,CO_(2)removaltechnologies(such as Bioenergy with carbon capture and storage),and CO_(2)capture,utilization and storage technologies,but should be cautionfor their scales and tradeoffs.
基金supported by the second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK1001)the Basic Research to Operation Funds of the Chinese Academy of Meteorological Sciences(2020Y004).
文摘Understanding climate change as well as its impacts on vegetation growth over the Tibetan Plateau has important implication for ecosystems.This study investigated changes in drought conditions and their impacts on vegetation growth over the Tibetan Plateau.The results reveal that the precipitation in growing season(May-September)shows a significant increase over most parts of the central and eastern Tibetan Plateau during 1961—2019.Consequently,drought conditions have generally relieved except in the south and northeast where precipitation has decreased.Combining analyses of gridded-dataset-derived drought indices with vegetation indices during 1982—2015,vegetation improvement in most regions of the Plateau is mainly due to lessened drought conditions.Noticeably,vegetation degradation is also found in part of southern Tibetan Plateau mainly resulting from drought enhancement.This study is expected to provide scientific basis for understanding of change in drought condition and its impacts on vegetation over different regions of TP under global warming background.