Wintertime Cyclone Activity and Its Relation to Precipitation over China

The authors examined the variability in wintertime cyclone activity and storm tracks and their relation to precipitation over China for the period 1951-2006 using the observational data.Two apparent modes of variability were assumed for the cyclone activity and storm tracks.The first mode describes the oscillation in the strength of the storm tracks in East Asia,which significantly increased since the mid-1980s,whereas the second mode describes a seesaw oscillation in the storm track strength between the Central-Southeast China and northem East Asia.The storm tracks over the Central-Southeast China have increased since the late 1960s.The possible causes for the variation of the cyclone activity and storm tracks are also explored.It is shown that wintertime precipitation,which has increased since the mid-1980s,concentrates in Central-Southeast China.The enhancement may be caused by the first mode of variability of storm tracks,whereas the interannual variability of precipitation may be linked to the second mode of the storm track variability.

China–Sri Lanka Joint Center for Education and Research for the 21st Century Maritime Silk Road

The China–Sri Lanka Joint Center for Education and Research for the 21 st Century Maritime Silk Road（CSL-CER） was established in August 2015. The Joint Center is an overseas science and education platform established by Chinese Academy of Sciences. CSL-CER has conducted a series of research activities, including an annual scientific expedition to the eastern Indian Ocean, with many kinds of instruments installed for monsoon and ocean observation. The ‘Numerical Forecast System for the Surrounding Area of Sri Lanka,＇ which was developed by the Joint Center, can provide rapid mapping on multiple scales and at multiple resolutions for numerical forecast products serving local society. The annual China–Sri Lanka Joint Workshop on Monsoon Climate and Ocean Environment was successfully held in 2015 and 2016. According to the Memorandum of Understanding（MOU） on joint Master＇s degrees, 15 new Master＇s students were accepted by University of Chinese Academy of Sciences（UCAS） in 2015.

CLIMATOLOGICAL CHARACTERISTICS FOR THE ONSET OF ASIAN SUMMER MONSOON AS REVEALED BY HIRS-Tb12 AND DROUGHT AND FLOODS IN EASTERN CHINA

As shown in comparison and study of the HIRS-Tb12 data and conventional data, temperature, humidity and vertical motion are structured differently in the Southern and Northern Hemispheres, which are well depicted with the HIRS-Tb12 data. When high pressures rapidly decrease over the regions of South China Sea and Arabian Sea with the HIRS-Tb12 less than 200 W/m2, monsoons will set off in the South China Sea, Arabian Sea and Bay of Bengal, respectively. From a year of significant drought to one of significant floods, the trend of evolution is significantly different in the downdraft areas of the subtropical highs between the two hemispheres.

The Relationship between Precipitation and Airflow over the Tibetan Plateau in Boreal Summer

Based on the observation data and the reanalysis datasets, the variability and the circulation features influencing precipitation in the Tibetan Plateau (TP) are investigated. Taking into account the effects of topography, surface winds are deconstructed into flow-around and flow-over components relative to the TP. Climatologically, the flow-around component mainly represents cyclonic circulation in the TP during the summer. The transition zone of total precipitation in the summer parallels the convergence belt between the southerlies and the northerlies of the flow-over component. The leading mode of rainfall anomalies in the TP has a meridional dipole structure, and the first principal component (PC1) mainly depicts the variation of rainfall in the southern TP. The wet southern TP experiences strengthened flow-over, which in turn mechanistically favors intensified ascent forced by the flow-over component. In addition, variations in the Indian summer monsoon (ISM) have an important role in influencing the flow over the southern TP, and the ISM ultimately impacts the precipitation over southern TP.