气候变化领域集成服务门户(CCPortal): Quantifying Convective Aggregation Using the Tropical Moist Margin's Length

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DOI	10.1029/2020MS002092
	Quantifying Convective Aggregation Using the Tropical Moist Margin's Length
	Beucler T.; Leutwyler D.; Windmiller J.M.
发表日期	2020
ISSN	19422466
卷号	12 期号:10
英文摘要	On small scales, the tropical atmosphere tends to be either moist or very dry. This defines two states that, on large scales, are separated by a sharp margin, well identified by the antimode of the bimodal tropical column water vapor distribution. Despite recent progress in understanding physical processes governing the spatiotemporal variability of tropical water vapor, the behavior of this margin remains elusive, and we lack a simple framework to understand the bimodality of tropical water vapor in observations. Motivated by the success of coarsening theory in explaining bimodal distributions, we leverage its methodology to relate the moisture field's spatial organization to its time evolution. This results in a new diagnostic framework for the bimodality of tropical water vapor, from which we argue that the length of the margin separating moist from dry regions should evolve toward a minimum in equilibrium. As the spatial organization of moisture is closely related to the organization of tropical convection, we hereby introduce a new convective organization index (BLW) measuring the ratio of the margin's length to the circumference of a well-defined equilibrium shape. Using BLW, we assess the evolution of self-aggregation in idealized cloud-resolving simulations of radiative-convective equilibrium and contrast it to the time evolution of the Atlantic Intertropical Convergence Zone (ITCZ) in the ERA5 meteorological reanalysis product. We find that BLW successfully captures aspects of convective organization ignored by more traditional metrics, while offering a new perspective on the seasonal cycle of convective organization in the Atlantic ITCZ. ©2020 The Authors.
英文关键词	convection; ITCZ; organization index; potential; self-aggregation; water vapor
语种	英语
scopus关键词	Coarsening; Moisture; Tropical engineering; Water vapor; Bimodal distribution; Cloud resolving simulations; Intertropical convergence zone; Radiative-convective equilibrium; Spatial organization; Spatiotemporal variability; Tropical atmospheres; Water vapor distribution; Tropics; equilibrium; intertropical convergence zone; quantitative analysis; spatiotemporal analysis; tropical meteorology; water vapor
来源期刊	Journal of Advances in Modeling Earth Systems
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/156614
作者单位	Department of Earth System Science, University of California, Irvine, CA, United States; Department of Earth and Environmental Engineering, Columbia University, New York, NY, United States; Max Planck Institute for Meteorology, Hamburg, Germany
推荐引用方式 GB/T 7714	Beucler T.,Leutwyler D.,Windmiller J.M.. Quantifying Convective Aggregation Using the Tropical Moist Margin's Length[J],2020,12(10).
APA	Beucler T.,Leutwyler D.,&Windmiller J.M..(2020).Quantifying Convective Aggregation Using the Tropical Moist Margin's Length.Journal of Advances in Modeling Earth Systems,12(10).
MLA	Beucler T.,et al."Quantifying Convective Aggregation Using the Tropical Moist Margin's Length".Journal of Advances in Modeling Earth Systems 12.10(2020).