春季西南极洲云相态的分布特征及其与南半球环状模的关系  

Spatial Distribution of Cloud Phase over the Western Antarctica in Spring Season and Its Relationship with Southern Hemisphere Annual Mode

作　　者：张昊天 刘敬武 李春 Zhang Haotian;Liu Jingwu;LI Chun(College of Oceanic and Atmospheric Science, Ocean University of China, Qingdao 266100, China)

机构地区：[1]中国海洋大学海洋与大气学院,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2021年第10期22-31,共10页Periodical of Ocean University of China

基　　金：国家重点基础研究发展计划项目(2018YFA0605704)资助。

摘　　要：基于星载激光雷达资料、再分析资料以及云与地球辐射能系统提供的云辐射资料,对2006—2017年春季云相态在西南极洲上空的分布和云相态随南半球环状模(Southern Hemisphere Annual Mode,SAM)指数的年际变化进行研究。研究显示,冰云主要分布于南极大陆2~10 km的高空,而含液水云主要分布于南极冰架或南大洋1~4 km的低空。两种云相态频率受地形抬升和水汽输运影响较大,使其在迎风坡的云相态频率远高于背风坡。利用SAM指数与云相态频率进行回归分析,发现云相态频率的年际变化在水平和垂直方向上表现出了明显的空间分布特征。这些特征是由SAM变化所引起的风场变化所驱动,使风场与水汽的经向输运以阿蒙森低压为中心呈现东-西偶极子分布,并在南极半岛东侧低层大气产生焚风效应。云相态频率随SAM的时空变化使云辐射强迫在年际尺度上也发生了明显的变化,并通过云辐射强迫显著影响着西南极洲的地表能量收支平衡。In this paper,the springtime spatial distribution of cloud phase over the West Antarctica and the interannual variation of cloud phase with the Southern Hemisphere Annual Mode(SAM)index from 2006 to 2017 were studied,by using the spaceborne lidar data,reanalysis data and the cloud radiation data provided by Clouds and the Earth’s Radiant Energy System.It is shown that,ice clouds are mainly distributed in the high altitude of 2~10 km in the Antarctic continent as well as the liquid-bearing clouds are mainly distributed in the Antarctic ice shelf or the low altitude of 1~4 km in the Southern Ocean.Both of the cloud phase frequency is greatly affected by terrain uplift and water vapor transport,which makes the frequency of the two cloud phases on the windward slope is much higher than that on the leeward slope.By regression analysis of SAM index and cloud frequency,it is found that the interannual variation of cloud frequency in different phases shows obvious spatial distribution characteristics in horizontal and vertical directions.These characteristics are driven by the change of wind field caused by SAM,which makes the meridional transport of wind field and water vapor present an East-West oriented dipole distribution centered on the Amundsen Sea Low,and produce a foehn effect in the lower atmosphere on the east side of the Antarctic Peninsula.The change of cloud frequency makes the cloud radiation forcing change significantly on the interannual scale,and influences the surface energy balance of the West Antarctica through the effect of cloud radiation.

关 键 词：西南极洲 云相态 南半球环状模 年际变化 云辐射强迫 

分 类 号：P426.5[天文地球—大气科学及气象学]