Analysis of a Vortex Precipitation Event over Southwest China Using AIRS and In Situ Measurements

A strong precipitation event caused by the southwest vortex（SWV）, which affected Sichuan Province and Chongqing municipality in Southwest China on 10–14 July 2012, is investigated. The SWV is examined using satellite observations from AIRS（Atmospheric Infrared Sounder）, in situ measurements from the SWV intensive observation campaign, and MICAPS（Marine Interactive Computer-Aided Provisioning System） data. Analysis of this precipitation process revealed that：（1）heavy rain occurred during the development phase, and cloud water content increased significantly after the dissipation of the SWV;（2） the area with low outgoing longwave radiation values from AIRS correlated well with the SWV;（3） variation of the temperature of brightness blackbody（TBB） from AIRS reflected the evolution of the SWV, and the values of TBB reduced significantly during the SWV＇s development; and（4） strong temperature and water vapor inversions were noted during the development of the SWV. The moisture profile displayed large vertical variation during the SWV＇s puissant phase,with the moisture inversion occurring at low levels. The moisture content during the receding phase was significantly reduced compared with that during the developing and puissant phases. The vertical flux of vapor divergence explained the variation of the moisture profile. These results also indicate the potential for using AIRS products in studying severe weather over the Tibetan Plateau and its surroundings, where in situ measurements are sparse.

Changes in snow cover extent in the Central Taurus Mountains from 1981 to 2021 in relation to temperature, precipitation, and atmospheric teleconnections

The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. In this study, we analyzed the monthly Snow Cover Extent(SCE) from November to April in the Central Taurus Mountains(Bolkar, Aladaglar, Tahtali and Binboga Mountains) from 1981 to 2021. Linear trends of snow cover season(November to April) over the last 41 years showed decreases in SCE primarily at lower elevations. The downward trend in SCE was found to be more pronounced and statistically significant for only November and March. SCE in the Central Taurus Mountains has declined about-6.3% per decade for 2500-3000 m in November and about-6.0% per decade for 1000-1500 m and 3000+ m in March over the last 41 years. The loss of SCE has become evident since the 2000s, and the lowest negative anomalies in SCE have been observed in 2014, 2001, and 2007 in the last 41 years, which are consistent with an increase in air temperature and decreased precipitation. SCE was correlated with both mean temperature and precipitation, with temperature having a greater relative importance at all elevated gradients. Results showed that there is a strong linear relationship between SCE and the mean air temperature(r =-0.80) and precipitation(r = 0.44) for all elevated gradients during the snow season. The Arctic Oscillation(AO), the North Atlantic Oscillation(NAO), and the Mediterranean Oscillation(MO) winter indices were used to explain the year-to-year variability in SCE over the Central Taurus Mountains. The results showed that the inter-annual variability observed in the winter SCE on the Central Taurus Mountains was positively correlated with the phases of the winter AO, NAO and MO, especially below 2000 m elevation.

STUDIES ON CLIMATE CHANGE IN CHINA IN RECENT 45 YEARS

Based on the data of monthly mean air temperature and precipitation from about 400 stations in 1951—1995.and the data of maximum and minimum air temperatures,relative humidity,total cloud cover and low-cloud cover,sunshine duration,evaporation,wind speed,snow-covered days and depth,and soil temperatures in 8 layers from 0 m down to 3.2 m from 200 odd stations in 1961 —1995.the climate change and its characteristics in China in recent 45 years have been analyzed and studied comprehensively.This paper,as the first part of the work.has analyzed the climate change and regularities of such meteorological elements as mean air temperature,maximum and minimum air temperatures,precipitation,relative humidity and sunshine duration.The possible mechanism on climate change in China and the climate change and regularities of other meteorological elements will be discussed in another paper as the second part.