DOI: 10.1002/2014MS000334
Scopus记录号: 2-s2.0-85027941201
论文题名: Precipitation characteristics of CAM5 physics at mesoscale resolution during MC3E and the impact of convective timescale choice
作者: Gustafson W ; I ; , Ma P ; -L ; , Singh B
刊名: Journal of Advances in Modeling Earth Systems
ISSN: 19422466
出版年: 2014
卷: 6, 期: 4 起始页码: 1271
结束页码: 1287
语种: 英语
英文关键词: Heat convection
; Parameterization
; Precipitation (meteorology)
; Weather forecasting
; CAM5
; Community atmosphere model
; Convective parameterization
; Diurnal cycle
; Precipitation characteristics
; Time-scales
; Weather research and forecasting models
; WRF
; Rain
; accuracy assessment
; atmospheric convection
; climate modeling
; diurnal variation
; mesoscale meteorology
; parameterization
; precipitation assessment
; timescale
; United States
英文摘要: The physics suite of the Community Atmosphere Model version 5 (CAM5) has recently been implemented in the Weather Research and Forecasting (WRF) model to explore the behavior of the parameterization suite at high resolution and within the controlled setting of a limited area model. The initial paper documenting this capability characterized the behavior for a northern high-latitude region. This paper characterizes the precipitation characteristics for continental, midlatitude, springtime conditions during the Midlatitude Continental Convective Clouds Experiment (MC3E) over the central United States. This period exhibited a range of convective conditions from those driven strongly by large-scale synoptic regimes to more locally driven convection. The study focuses on the precipitation behavior at 32 km grid spacing to better anticipate how the physics will behave in a global model when used at similar grid spacing in the coming years. Importantly, one change to the Zhang-McFarlane deep convective parameterization when implemented in WRF was to make the convective timescale parameter an explicit function of grid spacing. This study examines the sensitivity of the precipitation to the default value of the convective timescale in WRF, which is 600 s for 32 km grid spacing, to the value of 3600 s used for 2° grid spacing in CAM5. For comparison, a 1200 s and an infinite convective timescale are also used. The results show that the 600 s timescale gives the most accurate precipitation amount over the central United States. However, this setting has the worst precipitation diurnal cycle, with the convection too tightly linked to the daytime surface heating. Longer timescales greatly improve the diurnal cycle but result in less precipitation and produce a low bias. An analysis of rain rates shows the accurate precipitation amount with the shorter timescale is assembled from an over abundance of drizzle combined with too few heavy rain events. With longer timescales, one can improve the frequency distribution, particularly for the extreme rain rates. Ultimately, without changing other aspects of the physics, one must decide between accurate diurnal timing and rain amount when choosing an appropriate convective timescale. © 2014. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/76080
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, United States
Recommended Citation:
Gustafson W,I,, Ma P,et al. Precipitation characteristics of CAM5 physics at mesoscale resolution during MC3E and the impact of convective timescale choice[J]. Journal of Advances in Modeling Earth Systems,2014-01-01,6(4)