DOI: 10.1175/JCLI-D-11-00215.1
Scopus记录号: 2-s2.0-84862732563
论文题名: A numerical investigation of wet and dry onset modes in the North American Monsoon Core region. Part I: A regional mechanism for interannual variability
作者: Turrent C. ; Cavazos T.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2012
卷: 25, 期: 11 起始页码: 3953
结束页码: 3969
语种: 英语
Scopus关键词: Climate variability
; Composite fields
; Core region
; Deep convection
; Diurnal cycle
; Eastern pacific
; Gulf of California
; Inner domain
; Interannual variability
; Internal dynamics
; Key feature
; Land-sea thermal contrasts
; Mesoscale model
; Moisture fluxes
; Monsoons
; North American
; Numerical investigations
; Pennsylvania
; Primary sources
; Reanalysis
; Surface temperatures
; Wet and dry
; Climate models
; Climatology
; Moisture
; Natural convection
; Atmospheric thermodynamics
; annual variation
; anticyclone
; atmospheric convection
; climate modeling
; diurnal variation
; dry season
; moisture flux
; monsoon
; numerical model
; precipitation (climatology)
; surface temperature
; wet season
; Gulf of California
; Mexico [North America]
; Pacific Ocean
; Sierra Madre
; Sierra Madre Occidental
英文摘要: In this study the results of two regional fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5) simulations forced at their boundaries with low-pass-filtered North American Regional Reanalysis (NARR) composite fields from which synoptic-scale variability was removed are presented. The filtered NARR data are also assimilated into the inner domain through the use of field nudging. The purpose of this research is to investigate wet and dry onset modes in the core region of the North American monsoon (NAM). Key features of the NAM that are present in the NARR fields and assimilated into the regional simulations include the position of the midlevel anticyclone, low-level circulation over the Gulf of California, and moisture flux patterns into the core monsoon region, for which the eastern Pacific is the likely primary source of moisture. The model develops a robust diurnal cycle of deep convection over the peaks of the Sierra Madre Occidental (SMO) that results solely from its radiation scheme and internal dynamics, in spite of the field nudging. The wet onset mode is related to a regional land-sea thermal contrast (LSTC) that is ~2°C higher than in the dry mode, and is further characterized by a northward-displaced midlevel anticyclone, a stronger surface pressure gradient along the Gulf of California, larger mean moisture fluxes into the core region from the eastern Pacific, a stronger diurnal cycle of deep convection, and the more northward distribution of precipitation along the axis of the SMO. A proposed regional LSTC mechanism for NAM onset interannual variability is consistent with the differences between both onset modes. © 2012 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/52374
Appears in Collections: 气候变化事实与影响
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作者单位: Departmento de Oceanografía Física, Centro de Investigació n Científica, Educación Superior de Ensenada, Ensenada, Baja California, Mexico; Departamento de Oceanología, Centro Interdisciplinario de Ciencias Marinas-Instituto Politécnico Nacional, La Paz, Baja California, Mexico
Recommended Citation:
Turrent C.,Cavazos T.. A numerical investigation of wet and dry onset modes in the North American Monsoon Core region. Part I: A regional mechanism for interannual variability[J]. Journal of Climate,2012-01-01,25(11)