Aircraft observations of aerosol, cloud, precipitation, and boundary layer properties in pockets of open cells over the southeast Pacific
Aircraft observations of aerosol, cloud, precipitation, and boundary layer properties in pockets of open cells over the southeast Pacific
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飞机对东南太平洋上空开放单元中气溶胶、云、降水和边界层特性的观测
DOI：
10.5194/acp-14-8071-2014
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发表时间：
2014
影响因子：
6.3
通讯作者：
G. Painter
中科院分区：
文献类型：
--
作者：
C. Terai;C. Bretherton;R. Wood;G. Painter
抽象的。五口袋的开细胞（POC）的研究使用飞机飞行的VOCALS区域实验（VOCALS-REx），在2008年10月和11月在东南太平洋进行。地球同步卫星GOES-10的卫星图像用于区分POC区域，飞机飞行的测量值用于比较POC内外的气溶胶、云、降水和边界层条件。还比较了各个POC病例中观察到的情况。在逆温高度（1250至1600米）和地面风速（5至11米/秒）范围很广的边界层中观测到POC，在两个月的实地活动期间，POC与观测到的地面和自由对流层条件没有显着差异。在所有情况下，与周围的阴天相比，POC边界层更加分离，支持薄层状和较深的积云。尽管在每种情况下，POC中的云底降水率都高于阴天，但区分POC降水和阴天降水的阈值降水率并不存在。在不同的POC情况下，POC中的平均云基降水率可以从1.7到5.8 mm d−1不等。边界层较低位置的毛毛雨（> 0 dBZ）的出现更好地区分了POC降水和阴天降水，可能导致POC中冷池的形成更加活跃。POC云的云滴数浓度至少比阴天小8倍，且POC云中的毛毛雨与云水的比值比阴天大一个数量级以上，表明POC云中的碰撞合并过程增强。尽管在周围的阴天区域（65 ~ 324 cm−3）观测到的累积模式气溶胶浓度有很大的变化，但在所有五个POC的云下层观测到的累积模式气溶胶浓度的范围都要窄得多（24 ~ 40 cm−3），而起源于这一层的积云上升气流中的云滴浓度反映了这种有限的变化。在POC云下层上方存在一个超净层，其气溶胶浓度为积累型
Abstract. Five pockets of open cells (POCs) are studied using aircraft flights from the VOCALS Regional Experiment (VOCALS-REx), conducted in October and November 2008 over the southeast Pacific Ocean. Satellite imagery from the geostationary satellite GOES-10 is used to distinguish POC areas, and measurements from the aircraft flights are used to compare aerosol, cloud, precipitation, and boundary layer conditions inside and outside of POCs. Conditions observed across individual POC cases are also compared. POCs are observed in boundary layers with a wide range of inversion heights (1250 to 1600 m) and surface wind speeds (5 to 11 m s−1) and show no remarkable difference from the observed surface and free-tropospheric conditions during the two months of the field campaign. In all cases, compared to the surrounding overcast region the POC boundary layer is more decoupled, supporting both thin stratiform and deeper cumulus clouds. Although cloud-base precipitation rates are higher in the POC than the overcast region in each case, a threshold precipitation rate that differentiates POC precipitation from overcast precipitation does not exist. Mean cloud-base precipitation rates in POCs can range from 1.7 to 5.8 mm d−1 across different POC cases. The occurrence of heavy drizzle (> 0 dBZ) lower in the boundary layer better differentiates POC precipitation from overcast precipitation, likely leading to the more active cold pool formation in POCs. Cloud droplet number concentration is at least a factor of 8 smaller in the POC clouds, and the ratio of drizzle water to cloud water in POC clouds is over an order of magnitude larger than that in overcast clouds, indicating an enhancement of collision–coalescence processes in POC clouds. Despite large variations in the accumulation-mode aerosol concentrations observed in the surrounding overcast region (65 to 324 cm−3), the accumulation-mode aerosol concentrations observed in the subcloud layer of all five POCs exhibit a much narrower range (24 to 40 cm−3), and cloud droplet concentrations within the cumulus updrafts originating in this layer reflect this limited variability. Above the POC subcloud layer exists an ultraclean layer with accumulation-mode aerosol concentrations
2008 年 11 月 13 日 VOCALS-REx 期间沿 20°S 断面气溶胶和云微物理变化的观测
影响因子：
3.1
作者：
Cui Z
通讯作者：
Cui Z
VOCALS-REx 期间气象局预报模型中的层积云预测评估
影响因子：
6.3
作者：
Abel S
通讯作者：
Abel S