气候变化领域集成服务门户(CCPortal): Impact of Convectively Detrained Ice Crystals on the Humidity of the Tropical Tropopause Layer in Boreal Winter

CCPortal

DOI	10.1029/2020JD032894
	Impact of Convectively Detrained Ice Crystals on the Humidity of the Tropical Tropopause Layer in Boreal Winter
	Ueyama R.; Jensen E.J.; Pfister L.; Krämer M.; Afchine A.; Schoeberl M.
发表日期	2020
ISSN	2169897X
卷号	125 期号:14
英文摘要	Deep convection detraining in the uppermost tropical troposphere is capable of transporting water vapor and ice into the tropical tropopause layer (TTL), but the impact of deep convection on the global and regional TTL water vapor budget remains uncertain. In particular, the role of convectively detrained ice crystals that remain suspended after active convection has subsided is not well understood. These ice crystals represent aging cirrus anvils detached from the convective core. We use a cloud microphysical model that tracks individual ice crystals throughout their lifetimes to quantify the impact of detrained ice on the humidity of the TTL during boreal winter. Convective influence of air parcels near the wintertime cold point tropical tropopause is determined by tracing thousands of backward trajectories through satellite-derived, global, 3-hourly convective cloud-top altitude fields. Detrained ice, most of which is found over the tropical western Pacific, experiences cooling on the order of 1 K day−1 downstream of convection. Downstream cooling increases relative humidity and explains the observed supersaturated TTL over this region. Vapor in excess of saturation condenses onto the detrained ice, which ultimately brings the relative humidity down to saturation. Thus, convectively detrained ice crystals in aging anvils predominantly dehydrate the TTL, but the effect is small (0.01 ppmv). Moistening by active convection (0.30 ppmv), including the rapid sublimation of convectively lofted ice crystals near the tops of core anvils, overwhelms the dehydration by aging anvil ice crystals detrained from the core. The net effect is moistening by convective core anvils during boreal winter. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	convection; detrained ice crystals; tropical tropopause layer
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185894
作者单位	NASA Ames Research Center, Moffett Field, CA, United States; NCAR, Boulder, CO, United States; Institute for Energy and Climate Research-Stratosphere (IEK-7), Forschungzentrum Jülich, Jülich, Germany; Institute for Physics of the Atmosphere, Johannes Gutenberg University, Mainz, Germany; Science and Technology Corporation, Columbia, MD, United States
推荐引用方式 GB/T 7714	Ueyama R.,Jensen E.J.,Pfister L.,et al. Impact of Convectively Detrained Ice Crystals on the Humidity of the Tropical Tropopause Layer in Boreal Winter[J],2020,125(14).
APA	Ueyama R.,Jensen E.J.,Pfister L.,Krämer M.,Afchine A.,&Schoeberl M..(2020).Impact of Convectively Detrained Ice Crystals on the Humidity of the Tropical Tropopause Layer in Boreal Winter.Journal of Geophysical Research: Atmospheres,125(14).
MLA	Ueyama R.,et al."Impact of Convectively Detrained Ice Crystals on the Humidity of the Tropical Tropopause Layer in Boreal Winter".Journal of Geophysical Research: Atmospheres 125.14(2020).