2020年夏季超长梅雨过程中不同等湿静力能层的大气质量收支  

Air Mass Budget at the Different Iso-Moist Static Energy Levels during the Super Long-Lasting Meiyu in the Summer of 2020

作　　者：缪玉洁 虞越越 陈刚 管兆勇 李熙晨[2] MIAO Yujie;YU Yueyue;CHEN Gang;GUAN Zhaoyong;LI Xichen(School of Atmospheric Sciences/Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC–FEMD),Nanjing University of Information Science and Technology,Nanjing 210044;Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;University of California,Los Angeles,US 90001)

机构地区：[1]南京信息工程大学大气科学学院/气象灾害教育部重点实验室(KLME)/气象与环境联合研究中心(ILCEC)/气象灾害预报预警与评估省部共建协同创新中心(CIC–FEMD),南京210044 [2]中国科学院大气物理研究所,北京100029 [3]加利福尼亚大学洛杉矶分校,洛杉矶90001

出　　处：《大气科学》2024年第5期1743-1761,共19页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目42088101;国家重点研发计划项目2019YFC1510201;江苏省自然科学基金项目BK20211288。

摘　　要：本文运用欧洲中期天气预报中心(ECMWF)1980~2020年ERA5再分析数据集,从等湿静力能(MSE)大气质量环流的角度研究了2020年夏季超长梅雨期间各等MSE层大气质量和质量通量的特征及其与降水的关系。结果表明,在2020年超长梅雨过程中,从热带到中纬度梅雨区大气普遍向更高的等湿静力能层抬升。345~350 kJ/335~340 kJ等MSE层的质量异常增多/减少最为显著且与区域降水呈显著的同期正/负相关,因此335~350 kJ是2020年梅雨季的关键MSE变化范围。来自热带印度洋和热带西太平洋的高能空气向梅雨区汇聚是此次梅雨降水异常的重要原因,而局地静力不稳定性并无显著偏强异常。梅雨区345~350 kJ/340~345 kJ等MSE层大气质量日变化由绝热质量通量异常主导,进一步发现这两层的绝热质量通量异常超前降水1~2 d时两者的正/负相关性最好。在梅雨季的不同阶段,强降水前期等MSE绝热质量通量异常特征及其经纬向分量的相对重要性有所不同。在梅雨季初期,强降水前一天梅雨区345~350 kJ等MSE层质量收支异常偏多,主要由经向质量通量异常贡献;在梅雨季末期,强降水前两天梅雨区340~345 kJ层质量收支异常偏少,主要由纬向质量通量异常贡献。上述等MSE质量环流异常信号可以作为出入梅时间及梅雨强度的前兆信号之一。Using the European Centre for Medium-Range Weather Forecasts(ECMWF)ERA5 reanalysis dataset from 1980 to 2020,an iso-Moist Static Energy(iso-MSE)mass circulation analysis was conducted to investigate the characteristics of air masses and mass fluxes at various iso-MSE levels and their relationships with precipitation during the super long-lasting Meiyu in 2020.Results showed that during the super long-lasting Meiyu season in 2020,the air masses rose to higher iso-MSE levels from the tropics to midlatitudes.The most remarkable air mass gain and loss values were found in the iso-MSE layers of 345–350 kJ and 335–340 kJ,respectively.Strong positive and negative simultaneous correlations occurred between the regional-averaged precipitation anomalies over the Meiyu region and the air mass anomalies in the iso-MSE layers of 345–350 kJ and 335–340 kJ,respectively,indicating that MSE changes in the range of 335–350 kJ are critical to the Meiyu season.The convergence of high-energy air masses from the tropical Indian Ocean and tropical western Pacific in the Meiyu region is an important contributor to the abnormal Meiyu,while abnormally strong local static instability was not found.The adiabatic mass flux anomalies in the 340–345 kJ and 345–350 kJ iso-MSE layers over the Meiyu region drove the daily mass changes and are negatively and positively correlated,respectively,with precipitation at lead times of 1–2 days.The features of the iso-MSE mass flux anomalies and the relative importance of their meridional and zonal components in the periods before heavy precipitation vary at distinct stages of the Meiyu season.Just before the onset of the Meiyu season,the anomalous mass gain in the 345–350 kJ iso-MSE layer was attributed to the anomalous meridional mass flux,which preceded the heavy precipitation by 1 day.At the end of the Meiyu season,the anomalous mass loss in the 340–345 kJ iso-MSE layer was contributed by the anomalous zonal mass flux approximately 2 days prior to precipitation variations.Such anom

关 键 词：超长梅雨 湿静力能 大气质量环流 

分 类 号：P466[天文地球—大气科学及气象学]