青藏高原三江源地区正在面临着以“变暖变湿”为主的气候变化,是气候变化的显著区与敏感区。基于中国气象局位于三江源地区20个地面台站的气温、降水数据以及HadCRUT4(Climatic Research Unit land-surface air temperature-4 dataset a...青藏高原三江源地区正在面临着以“变暖变湿”为主的气候变化,是气候变化的显著区与敏感区。基于中国气象局位于三江源地区20个地面台站的气温、降水数据以及HadCRUT4(Climatic Research Unit land-surface air temperature-4 dataset and the Hadley Centre sea-surface temperature dataset,Hadley Centre,UK)气温、PREC(Precipitation Reconstruction,National Oceanic and Atmospheric Administration,USA)降水资料,从气候要素空间格局、极端气候指标以及区域-全球平均多年变化对比等3个方面系统总结了三江源地区1961-2019年气候和极端气候变化的特征。结果显示,三江源区域在过去近60 a里平均增暖速率为0.37℃/(10 a),是全球平均水平(0.16℃/(10 a))的2倍以上,同时大幅高于全球同纬度(0.19℃/(10 a))及中国区域(0.28℃/(10 a))。在全球变暖背景下,三江源地区大部分极端气候指标上升,其中以夜间最低气温的上升(0.55℃/(10 a))最为显著,且极端高温事件的出现频率上升,区域日温差减小、气温变化极端性增强。三江源近60 a温湿气候态的空间格局为沿西北-东南方向的正温湿梯度,其变化趋势存在自西向东速率上升的暖湿化空间分异特征。本文的研究结论进一步揭示了三江源地区近60 a气候变化与极端气候的时空格局,为三江源地区气候系统和生态系统的脆弱性研究以及未来气候变化预估提供了科学依据,同时也为气候变化敏感的高寒地区对全球变暖的响应研究提供了对比案例。展开更多
Lake surface water-heat exchange and its climatic attribution critically influence alpine lakes’evaporation mechanism and water storage balance with climate change.Here,this paper first explored the hourly,daily,and ...Lake surface water-heat exchange and its climatic attribution critically influence alpine lakes’evaporation mechanism and water storage balance with climate change.Here,this paper first explored the hourly,daily,and monthly water-heat flux variations of the lake surface and their correlations with meteorological factors based on the eddy covariance turbulent flux observation over the Yamzhog Yumco,an alpine lake in south Tibet in the non-freezing period(April-December)in 2016 and 2017.We found that the average latent heat flux was much higher than the sensible heat flux on the lake surface from April to December.Meanwhile,the water-heat flux exhibited remarkable seasonal variation,with a prominent role of higher air temperature and humidity in summer jointly controlling the lake-air energy exchange.Moreover,the main controlling meteorological factors for the water-heat flux variation of the lake surface differed with diversified timescales.First,the lake-air temperature difference was the most significant meteorological factor related to sensible heat flux on the half-hourly,daily,and monthly timescales.Second,the latent heat flux was strongly positively correlated with wind speed and the synergies of wind speed and water vapor pressure deficit on the daily and half-hourly timescales.Third,the lake surface heat flux was significantly negatively correlated with net radiation flux on the daily and monthly scales.The negative correlation can be attributed to the seasonal variation of the water surface net radiation,and the phase difference in heat flux intensity caused by the lake-air temperature difference and heat capacity contrast.Our findings will hopefully improve the understanding of energy exchange and evaporation mechanisms for alpine lakes in a warming climate.展开更多
文摘青藏高原三江源地区正在面临着以“变暖变湿”为主的气候变化,是气候变化的显著区与敏感区。基于中国气象局位于三江源地区20个地面台站的气温、降水数据以及HadCRUT4(Climatic Research Unit land-surface air temperature-4 dataset and the Hadley Centre sea-surface temperature dataset,Hadley Centre,UK)气温、PREC(Precipitation Reconstruction,National Oceanic and Atmospheric Administration,USA)降水资料,从气候要素空间格局、极端气候指标以及区域-全球平均多年变化对比等3个方面系统总结了三江源地区1961-2019年气候和极端气候变化的特征。结果显示,三江源区域在过去近60 a里平均增暖速率为0.37℃/(10 a),是全球平均水平(0.16℃/(10 a))的2倍以上,同时大幅高于全球同纬度(0.19℃/(10 a))及中国区域(0.28℃/(10 a))。在全球变暖背景下,三江源地区大部分极端气候指标上升,其中以夜间最低气温的上升(0.55℃/(10 a))最为显著,且极端高温事件的出现频率上升,区域日温差减小、气温变化极端性增强。三江源近60 a温湿气候态的空间格局为沿西北-东南方向的正温湿梯度,其变化趋势存在自西向东速率上升的暖湿化空间分异特征。本文的研究结论进一步揭示了三江源地区近60 a气候变化与极端气候的时空格局,为三江源地区气候系统和生态系统的脆弱性研究以及未来气候变化预估提供了科学依据,同时也为气候变化敏感的高寒地区对全球变暖的响应研究提供了对比案例。
基金The Second Tibetan Plateau Scientific Expedition and Research Program(STEP),No.2019QZKK0202-02National Natural Science Foundation of China,No.41471064。
文摘Lake surface water-heat exchange and its climatic attribution critically influence alpine lakes’evaporation mechanism and water storage balance with climate change.Here,this paper first explored the hourly,daily,and monthly water-heat flux variations of the lake surface and their correlations with meteorological factors based on the eddy covariance turbulent flux observation over the Yamzhog Yumco,an alpine lake in south Tibet in the non-freezing period(April-December)in 2016 and 2017.We found that the average latent heat flux was much higher than the sensible heat flux on the lake surface from April to December.Meanwhile,the water-heat flux exhibited remarkable seasonal variation,with a prominent role of higher air temperature and humidity in summer jointly controlling the lake-air energy exchange.Moreover,the main controlling meteorological factors for the water-heat flux variation of the lake surface differed with diversified timescales.First,the lake-air temperature difference was the most significant meteorological factor related to sensible heat flux on the half-hourly,daily,and monthly timescales.Second,the latent heat flux was strongly positively correlated with wind speed and the synergies of wind speed and water vapor pressure deficit on the daily and half-hourly timescales.Third,the lake surface heat flux was significantly negatively correlated with net radiation flux on the daily and monthly scales.The negative correlation can be attributed to the seasonal variation of the water surface net radiation,and the phase difference in heat flux intensity caused by the lake-air temperature difference and heat capacity contrast.Our findings will hopefully improve the understanding of energy exchange and evaporation mechanisms for alpine lakes in a warming climate.
