利用Ka波段云雷达对青藏高原三类重要天气系统云宏观参数日变化特征的研究  

Study of Diurnal Variation of Cloud Macro Parameters in Three Important Weather Systems over the Tibetan Plateau Using Ka-Band Cloud Radar

作　　者：武静雅 孙强[1,3] 毕永恒[1,3] 田玉芳[1,3] 王一楠 吕达仁[1,2,3] Jingya WU;Qiang SUN;Yongheng BI;Yufang TIAN;Yinan WANG;Daren LÜ(Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;University of Chinese Academy of Science,Beijing 100049;Key Laboratory of Middle Atmosphere and Global Environment Observation,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029)

机构地区：[1]中国科学院大气物理研究所,北京100029 [2]中国科学院大学,北京100049 [3]中国科学院大气物理研究所中层大气和全球环境探测重点实验室,北京100029

出　　处：《大气科学》2022年第4期1030-1040,共11页Chinese Journal of Atmospheric Sciences

基　　金：青藏高原大气多要素垂直结构的高分辨率综合探测及对大气上下层相互作用的重要机制研究项目QYZDY-SSW-DQC027;第二次青藏高原科考国家专项2019QZKK0604;中国科学院先导专项XDA17010103。

摘　　要：青藏高原上空云宏观参数的日变化受大尺度环流、当地太阳辐射和地表过程的联合作用,对辐射收支、辐射传输及感热、潜热的分布等有重要影响。由于缺乏持续定量的观测,对各类天气系统云宏观参数日变化特征的了解还十分不足。多波段多大气成分主被动综合探测系统APSOS(Atmospheric Profiling Synthetic Observation System)的Ka波段云雷达是首部在青藏高原实现长期观测云的雷达。本文基于2019年全年APSOS的Ka波段云雷达资料,采用统计和快速傅里叶变换方法研究了西风槽、切变线和低涡三类重要天气系统影响下的有云频率、单层非降水云或者降水云非降水时段的云顶高度、云底高度和云厚日变化的时域和频域特征,得到了统计回归方程。主要结论有:(1)西风槽系统日均有云频率为56.9%,切变线系统为50.8%,低涡系统达73%。(2)尽管西风槽和切变线系统的成因不同,但两类系统云宏观参数的日变化趋势和主要谐波周期相似:日变化趋势基本为单峰单谷型,日出前最低,日落前最高。有云频率表现为日变化和半日变化,单层云云顶高度、云底高度和云厚主要表现为日变化。(3)低涡系统云宏观参数的日变化特征与前两类系统明显不同:日变化趋势表现为多峰多谷型,虽然有云频率和单层云云顶高度、云底高度主要谐波中均以日变化振幅最大,但频谱分布分散,云厚主要变化中振幅最大的是周期为4.8 h的波动。(4)得到了各系统有云频率、单层云云顶高度、云底高度和云厚日变化的统计回归方程。The diurnal variation of cloud macro parameters over the Tibetan Plateau is affected by the combined effects of large-scale circulation, local solar radiation and surface processes, while it also remarkably affects the radiation budget and transmission and the distribution of sensible and latent heat. Due to the lack of continuous quantitative observation,the understanding of the diurnal variation characteristics of the cloud macro parameters in various weather systems is still quite insufficient. Ka-band cloud radar of atmospheric profiling synthetic observation system(APSOS) is the first radar to realize long-term cloud observation in the Tibetan Plateau. In this paper, using statistical and Fast Fourier Transform methods, the data of the APSOS Ka-band cloud radar in 2019 are used to study the time-and frequency-domain diurnal variation characteristics of cloud frequency, single-layer cloud top height, cloud bottom height, and cloud thickness under the influence of westerly trough, shear line, and vortex system. The major conclusions are as follows:(1) The daily mean cloud frequency is 56.9% for the westerly trough system, 50.8% for the shear line system, and 73% for the vortex system.(2) Although the origins of the westerly trough and shear line system are different, the diurnal variation trend and main harmonic period of the cloud macro parameters of the two systems are similar: the diurnal variation trend is sinusoidal;the minimum value appears before sunrise, and the maximum value appears before sunset. The main harmonics of cloud frequency are diurnal(24 h) and semidiurnal(12 h), and the diurnal harmonics have the largest amplitude among the main harmonics of cloud top height, bottom height, and thickness.(3) The diurnal variation characteristics of cloud macro parameters in a vortex system are different from that in the first two systems. The diurnal variation of cloud parameters in the vortex system is multipeak type. Although the harmonic amplitude of the diurnal period is the largest among the main har

关 键 词：APSOS(多波段多大气成分主被动综合探测系统) Ka波段云雷达 云宏观参数 日变化 西风槽 低涡 

分 类 号：P401[天文地球—大气物理学与大气环境]