2000-2018年东亚地区云顶高度的时空变化特征

为了了解区域云顶高度对过去气候变化的响应,基于卫星搭载的MODIS传感器提供的2000年3月至2018年2月MOD03_08_v6.0数据,分析了东亚地区云顶高度2000—2018年的时空变化特征,并探讨其长期变化的原因。研究发现,东亚地区云顶高度呈西南高东北低的特征。云顶高度在东亚地区以0.020 km/a的变率增长,其中大陆东部云顶高度的年际变率为0.035 km/a,东部海域年际变率为0.034 km/a。在东部海域地区云顶高度的变化同海表温度的变化相关性较高,相关系数为0.68,这表明云顶高度的变化受下垫面的影响。在东亚地区30°~40°N区域内,年平均云顶高度的增加较为明显。此外,夏季云顶高度在长江中下游盆地、塔里木盆地、吐鲁番盆地以及四川盆地东北部呈-0.03 km/a的减少趋势,这是由于更多低云的形成降低了云顶高度;冬季云顶高度在东亚地区40°N以北呈下降趋势,而在40°N以南呈增加趋势。

The change of cloud top height over East Asia during 2000-2018

In order to know how regional averaged cloud top height (CTH) responded to the past climatic change, the spatial and temporal variations of CTH based on MODIS data (MOD03_08_v6.0) from March 2000 to February 2018 were analyzed. The results showed that the CTH in East Asia was higher in the southwest and lower in the northeast. The annual mean CTH was found to increase in East Asia at the rate of 0.020 km per year, of which, 0.035 km per year over the eastern land and 0.034 km per year over the eastern sea. The CTH changes statistically correlated with the sea surface temperature changes over the eastern sea (r=0.68), which indicates that the CTH changes may be affected by the underlying surface. Statistically significant increasing trend of annual mean CTH was found in the latitude zone of 30°-40°N. Furthermore, CTH showed decreasing trends of about -0.030 km per year in the Middle-Lower Yangtze River basin, Tarim basin, Turpan basin and northeastern Sichuan basin in summer since more low cloud formations benefited to the decrease of CTH. In winter, the decreasing trend of CTH was found over the north of 40°N, whereas the increasing trend was found over the south of 40°N in East Asia.