基于CERES卫星资料的青藏高原有效辐射变化规律

The Variation of Effective Radiation in Qinghai-Tibetan Plateau Based on the CERES Satellite Data

有效辐射作为地表辐射平衡的重要组成部分,其对大气的加热对辐射平衡,能量平衡以及周边大气环流起着重要的作用。基于2000-2014年的Aqua/CERES卫星产品地表长波辐射及其他相关参数,研究了青藏高原(下称高原)地区全天气和晴天两个不同条件下地表有效辐射的时空分布及其成因。结果表明:在高原地区有效辐射呈现出西部地区较大,东南部较小的空间分布。由于高原有效辐射的变化存在区域性的不同,应用经验正交分解方法将高原分为高原西部边缘(Ⅰ区)、中西部腹地(Ⅱ区)、东北(Ⅲ区)和东南(Ⅳ区)4个气候区。有效辐射与地表向上长波辐射的增加(减弱)趋势基本一致,而大气逆辐射的改变对有效辐射的影响在不同气候分区的不同季节呈现出不同的变化趋势,且云通过增加大气逆辐射进而减小有效辐射。在高原中西部腹地(Ⅱ区)以冷平流为主,相对湿度偏低,而在其他三个地区则以暖平流为主,相对湿度偏高。温度平流和大气水汽等因子均通过影响大气逆辐射进而影响有效辐射。研究结果可为认识高原整体非绝热加热特征及影响机理提供参考。

As an important component of surface radiation balance, effective radiation plays an important role in radiation balance, energy balance and atmospheric circulation. Based on the effective radiation and other relevant parameters of Aqua/CERES satellite products from 2000 to 2015, the spatial and temporal distribution of effec- tive radiation and its factors of the Qinghai-Tibetan Plateau （QTP） were analyzed under two different conditions, which is all-sky and clear-sky. The following conclusions were obtained： The effective radiation of the western region of QTP is larger than the southeast. Because of the regional differences of effective radiation, QTP was di- vided into four climatic regions by using the EOF method, which is the west edge （region ｜ ）, the midwest hin- terlandn （ region ]l ）, the northeast （ region 111 ） and the southeast （ region IV ）, The trend of effective radiation is consistent with the upward long-wave radiation with increased （reduced）, but the effect of the change of the at- mospheric counter radiation on the effective radiation showed different trends in different seasons and regions. The cloud reduces the effective radiation by increasing the atmospheric counter radiation. Over the past decade, the impact of cloud on the surface of the effective radiation was weakened. There is a positive correlation between the upward long-wave radiation and the surface temperature. Atmospheric counter radiation has a positive correla- tion with the atmospheric temperature and the relative humidity at 500 hPa. It is mainly cold advection and less relative humidity in the midwest hinterland of QTP （ region [[ ）, but in other three regions, it is mainly warm ad- vection and high relative humidity. These factors like cold （warm） advection or relative humidity affect effective radiation by impacting on the atmospheric counter radiation. The results can provide a reference for understanding the diabatic heating characteristics and the influence mechanism of QTP.