气候变化领域集成服务门户(CCPortal): Surface Expressions of Atmospheric Thermal Tides in the Tropical Atlantic and Their Impact on Open-Ocean Precipitation

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DOI	10.1029/2019JD031997
	Surface Expressions of Atmospheric Thermal Tides in the Tropical Atlantic and Their Impact on Open-Ocean Precipitation
	Christophersen J.A.; Foltz G.R.; Perez R.C.
发表日期	2020
ISSN	2169897X
卷号	125 期号:22
英文摘要	Diurnal and semidiurnal variations of atmospheric pressure and surface winds are fundamental to the Earth-Sun system. Past research in the tropical Pacific shows semidiurnal and diurnal patterns in the zonal and meridional wind anomalies, respectively. While the semidiurnal zonal wind pattern is consistent with atmospheric thermal tidal forcing, it is not yet certain what drives diurnal meridional wind variability. This study examines the diurnal cycle of meridional winds in the tropical Atlantic Ocean across four different seasons and the extent to which they impact the diurnal evolution of open-ocean precipitation in boreal summer. Comparisons of direct observations from long-term moored buoys to an atmospheric reanalysis (MERRA-2) show that MERRA-2 reproduces diurnal and semidiurnal pressure and wind variations. The MERRA-2 atmospheric thermal tides are decomposed into migrating and nonmigrating tidal components, and the linear terms in the zonal and meridional momentum equations are calculated. There is an approximate balance between the acceleration and pressure gradient terms for the zonal migrating momentum budget in the open ocean, with larger residuals or imbalances between those terms for the other budgets. The meridional nonmigrating budget shows largest residuals near the African coastline, indicating that nonlinear processes like the evening initiation of convection are important over land. This evening convection drives the meridional component of surface convergence which is translated offshore by the nonmigrating tide in the form of gravity waves, potentially modified by the African Easterly Jet. During boreal summer, this convergence helps to induce a morning peak of precipitation over the open ocean. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	atmospheric thermal tides; ocean observing systems; tropical Atlantic Ocean
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/185635
作者单位	National Research Council, Naval Research Laboratory, Monterey, CA, United States; NOAA/Atlantic Oceanographic and Meteorological Laboratory/Physical Oceanography Division, Miami, FL, United States
推荐引用方式 GB/T 7714	Christophersen J.A.,Foltz G.R.,Perez R.C.. Surface Expressions of Atmospheric Thermal Tides in the Tropical Atlantic and Their Impact on Open-Ocean Precipitation[J],2020,125(22).
APA	Christophersen J.A.,Foltz G.R.,&Perez R.C..(2020).Surface Expressions of Atmospheric Thermal Tides in the Tropical Atlantic and Their Impact on Open-Ocean Precipitation.Journal of Geophysical Research: Atmospheres,125(22).
MLA	Christophersen J.A.,et al."Surface Expressions of Atmospheric Thermal Tides in the Tropical Atlantic and Their Impact on Open-Ocean Precipitation".Journal of Geophysical Research: Atmospheres 125.22(2020).