DOI: 10.1007/s00382-012-1631-6
Scopus记录号: 2-s2.0-84884701089
论文题名: Boreal summer intraseasonal variability simulated in the NCEP climate forecast system: Insights from moist static energy budget and sensitivity to convective moistening
作者: Sooraj K.P. ; Seo K.-H.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2013
卷: 41, 期: 2017-05-06 起始页码: 1569
结束页码: 1594
语种: 英语
英文关键词: Cloud-radiation feedback
; Intraseasonal oscillation (ISO)
; Moist and thermodynamic process
; Moist static energy (MSE) budget
; RH-precipitation relationship
; Wind-evaporation feedback
英文摘要: The NCEP Climate Forecast System (CFS) with the relaxed Arakawa Schubert (RAS, hereafter referred to as CTRL) convection scheme of Moorthi and Suarez exhibits better performance in representing boreal summer tropical intraseasonal variability as compared with a simulation using simplified Arakawa-Schubert scheme. The intraseasonal moist static energy (MSE) budget is analyzed in this version of the CFS model (CTRL), which produces realistic eastward and northward propagation characteristics. The moist and thermodynamic processes involved in the maintenance and propagation of the poleward moving intraseasonal oscillation (ISO) disturbances are examined here. Budget diagnostics show that horizontal MSE advection is the principal component of the budget, contributing to the poleward movement of the convection. The injection of MSE moistens the atmosphere north of the convective area causing the poleward movement of convection by destabilization of the atmosphere. The moistening process is mainly contributed by the climatological wind acting on the anomalous moisture gradient as confirmed from the examination of moisture advection equation. While surface enthalpy fluxes (consisting of radiative and surface turbulent heat fluxes) maintain the ISO anomalies, they oppose the MSE tendency due to horizontal advection thus regulating the poleward propagation characteristics. In addition, the model results show that wind-evaporation feedback dominates over cloud-radiation feedback for ISO propagation; this is in contrast to our estimates using the newly available European Centre for Medium Range Weather Forecasts Interim reanalysis. Sensitivity experiments suggest that intraseasonal variability in the CFS model with the RAS scheme is highly sensitive to the parameterization of both the shallow convection and the convective rain evaporation and downdrafts. Removal of these components adversely affects the propagation characteristics and greatly reduces the amplitude of intraseasonal variability. Our results support the primary importance of the moisture preconditioning ahead of the ISO and the physical relationship between moisture and precipitation. For realistic ISO simulations, models need to represent these features appropriately. © 2012 Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54802
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Atmospheric Sciences, Pusan National University, Busan, 609-734, South Korea; Centre for Climate Change Research (CCCR), Indian Institute of Tropical Meteorology, Dr Homi Bhaba Road, Pashan, Pune, 411008, India
Recommended Citation:
Sooraj K.P.,Seo K.-H.. Boreal summer intraseasonal variability simulated in the NCEP climate forecast system: Insights from moist static energy budget and sensitivity to convective moistening[J]. Climate Dynamics,2013-01-01,41(2017-05-06)