利用中国站点降水和气温资料、NCEP/NCAR大气再分析资料和海温数据,总结了2021年春季(3—5月)我国气候异常特征,并初步分析了其可能成因。2021年春季全国平均气温为11.6℃,为1961年以来第四暖,但4月我国中部地区出现阶段性气温偏低;全...利用中国站点降水和气温资料、NCEP/NCAR大气再分析资料和海温数据,总结了2021年春季(3—5月)我国气候异常特征,并初步分析了其可能成因。2021年春季全国平均气温为11.6℃,为1961年以来第四暖,但4月我国中部地区出现阶段性气温偏低;全国平均降水量为145.3 mm,接近常年同期,但季内阶段性变化显著,这与环流的阶段性调整密切相关。3—4月亚洲中纬度环流为“东高西低”型,副热带高压偏弱偏东,有利于来自西北太平洋的水汽向长江以北输送,降水呈“北多南少”分布。5月中纬度环流转变为“东低西高”型,副热带高压西伸北扩,低层西南暖湿气流增强,在江南、华南强烈辐合上升,为强对流天气的频繁发生提供了有利条件,降水调整为“南多北少”分布。此外4月中旬开始,中高纬阻塞活动逐渐频繁,一方面导致我国中部地区气温阶段性偏低,另一方面也是造成南方强对流天气发生的重要因素之一。春季后期环流出现明显调整与高低纬度环流相互作用及热带海温的演变有关。4月中旬北极圈大气明显回暖,乌拉尔山高压脊增强,进而造成上述“东低西高”型环流异常;同时,随着5月热带印度洋的快速增暖,前期表现为对La Ni a事件响应的东亚低纬度环流形势也出现明显调整,从而导致季内降水分布也发生了明显变化。展开更多
Under the ongoing global warming,the sea surface temperature(SST)over the entire Indian Ocean(IO)has been warming saliently at a rate of 0.014°C yr-1since the 1950s,which is larger than that in other regions of t...Under the ongoing global warming,the sea surface temperature(SST)over the entire Indian Ocean(IO)has been warming saliently at a rate of 0.014°C yr-1since the 1950s,which is larger than that in other regions of the globe.The salient IO warming reflects the synergistic effect of global warming and the internal variability of the climate system,and the warming could lead to climate anomalies in peripheral regions.The simulation performance of the sustained IO warming was evaluated by comparing 37 CMIP5 and 37 CMIP6 models with observed data.The results show that the warming in the IO can be captured by nearly all the CMIP models,but most tend to underestimate the magnitude of IO warming trends.There is no qualitative improvement in the simulation of the salient IO warming from CMIP5 to CMIP6.In addition,six metrics were used to investigate the performance of all models.Concerning the spatial pattern of warming trends,the CMIP5 models reveal a better simulation performance than those in CMIP6 models.Only nine best models(seven CMIP5 models and two CMIP6 models)can simulate a high warming trend in the IO region of0.014±0.001°C yr-1during 1950–2005,but these nine models still have some disadvantages among other metrics.The overall evaluation here provides necessary information for future investigation about the mechanism of the sustained IO warming based on the climate models with better performances.展开更多
文摘利用中国站点降水和气温资料、NCEP/NCAR大气再分析资料和海温数据,总结了2021年春季(3—5月)我国气候异常特征,并初步分析了其可能成因。2021年春季全国平均气温为11.6℃,为1961年以来第四暖,但4月我国中部地区出现阶段性气温偏低;全国平均降水量为145.3 mm,接近常年同期,但季内阶段性变化显著,这与环流的阶段性调整密切相关。3—4月亚洲中纬度环流为“东高西低”型,副热带高压偏弱偏东,有利于来自西北太平洋的水汽向长江以北输送,降水呈“北多南少”分布。5月中纬度环流转变为“东低西高”型,副热带高压西伸北扩,低层西南暖湿气流增强,在江南、华南强烈辐合上升,为强对流天气的频繁发生提供了有利条件,降水调整为“南多北少”分布。此外4月中旬开始,中高纬阻塞活动逐渐频繁,一方面导致我国中部地区气温阶段性偏低,另一方面也是造成南方强对流天气发生的重要因素之一。春季后期环流出现明显调整与高低纬度环流相互作用及热带海温的演变有关。4月中旬北极圈大气明显回暖,乌拉尔山高压脊增强,进而造成上述“东低西高”型环流异常;同时,随着5月热带印度洋的快速增暖,前期表现为对La Ni a事件响应的东亚低纬度环流形势也出现明显调整,从而导致季内降水分布也发生了明显变化。
基金supported by the National Key R&D Program of China grant numbers 2016YFA0600602 and 2019YFC1510002the National Natural Science Foundation of China grant number 41776039。
文摘Under the ongoing global warming,the sea surface temperature(SST)over the entire Indian Ocean(IO)has been warming saliently at a rate of 0.014°C yr-1since the 1950s,which is larger than that in other regions of the globe.The salient IO warming reflects the synergistic effect of global warming and the internal variability of the climate system,and the warming could lead to climate anomalies in peripheral regions.The simulation performance of the sustained IO warming was evaluated by comparing 37 CMIP5 and 37 CMIP6 models with observed data.The results show that the warming in the IO can be captured by nearly all the CMIP models,but most tend to underestimate the magnitude of IO warming trends.There is no qualitative improvement in the simulation of the salient IO warming from CMIP5 to CMIP6.In addition,six metrics were used to investigate the performance of all models.Concerning the spatial pattern of warming trends,the CMIP5 models reveal a better simulation performance than those in CMIP6 models.Only nine best models(seven CMIP5 models and two CMIP6 models)can simulate a high warming trend in the IO region of0.014±0.001°C yr-1during 1950–2005,but these nine models still have some disadvantages among other metrics.The overall evaluation here provides necessary information for future investigation about the mechanism of the sustained IO warming based on the climate models with better performances.
