CALIPSO observations of wave-induced PSCs with near-unity optical depth over Antarctica in 2006-2007
CALIPSO observations of wave-induced PSCs with near-unity optical depth over Antarctica in 2006-2007
复制标题
2006-2007年南极上空近乎一致光学深度的波致PSC的CALIPSO观测
DOI：
10.1029/2008jd010604
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发表时间：
2009
影响因子：
--
通讯作者：
H. Chepfer
中科院分区：
文献类型：
--
作者：
V. Noel;A. Hertzog;H. Chepfer
[1]地面和卫星观测已经暗示了极地平流层云（PSC）的存在，其光学深度相对较高，即使光学深度值很难获得。这项研究记录了从星载激光雷达观察到的II型PSC，可见光深度高达0.8。与多个温度场的比较，包括再分析和中尺度模拟的结果，表明强烈的小尺度温度波动，由于重力波在其形成中发挥了重要作用，而附近的观测显示存在一个潜在的相关类型Ia PSC更远的下游内的极涡。继这第一个情况下，在南极洲的光学深度大于0.3的PSC的地理分布和微物理特性进行了探索，在2006年和2007年的冬季。这些云是罕见的（不到1%的剖面），集中在强风袭击西半球陡峭地面斜坡的地区，特别是在半岛。这种PSC比一般PSC群体更冷，它们的检测与南极洲的每日最低温度相关。这些云的激光雷达和消偏振比表明它们很可能是冰基的（II型）。该案例研究与其他PSC之间的相似性表明，它们可能具有相同的形成机制。
[1] Ground-based and satellite observations have hinted at the existence of polar stratospheric clouds (PSCs) with relatively high optical depths, even if optical depth values are hard to come by. This study documents a type II PSC observed from spaceborne lidar, with visible optical depths up to 0.8. Comparisons with multiple temperature fields, including reanalyses and results from mesoscale simulations, suggest that intense small-scale temperature fluctuations due to gravity waves play an important role in its formation, while nearby observations show the presence of a potentially related type Ia PSC farther downstream inside the polar vortex. Following this first case, the geographic distribution and microphysical properties of PSCs with optical depths above 0.3 are explored over Antarctica during the 2006 and 2007 austral winters. These clouds are rare (less than 1% of profiles) and concentrated over areas where strong winds hit steep ground slopes in the Western Hemisphere, especially over the peninsula. Such PSCs are colder than the general PSC population, and their detection is correlated with daily temperature minima across Antarctica. Lidar and depolarization ratios within these clouds suggest they are most likely ice-based (type II). Similarities between the case study and other PSCs suggest they might share the same formation mechanisms.