气候变化领域集成服务门户(CCPortal): Land–Atmosphere Coupling Sensitivity to GCMs Resolution: A Multimodel Assessment of Local and Remote Processes in the Sahel Hot Spot

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DOI	10.1175/JCLI-D-20-0303.1
	Land–Atmosphere Coupling Sensitivity to GCMs Resolution: A Multimodel Assessment of Local and Remote Processes in the Sahel Hot Spot
	Müller O.V.; Vidale P.L.; Vannière B.; Schiemann R.; Senan R.; Haarsma R.J.; Jungclaus J.H.
发表日期	2021
ISSN	0894-8755
起始页码	967
结束页码	985
卷号	34 期号:3
英文摘要	Land–atmosphere interactions are often interpreted as local effects, whereby the soil state drives local atmospheric conditions and feedbacks originate. However, nonlocal mechanisms can significantly modulate land–atmosphere exchanges and coupling. We make use of GCMs at different resolutions (low;18 and high;0.258) to separate the two contributions to coupling: better represented local processes versus the influence of improved large-scale circulation. We use a two-legged metric, complemented by a process-based assessment of four CMIP6 GCMs. Our results show that weakening, strengthening, and relocation of coupling hot spots occur at high resolution globally. The northward expansion of the Sahel hot spot, driven by nonlocal mechanisms, is the most notable change. The African easterly jet’s horizontal wind shear is enhanced in JJA due to better resolved orography at high resolution. This effect, combined with enhanced easterly moisture flux, favors the development of African easterly waves over the Sahel. More precipitation and soil moisture recharge produce strengthening of the coupling, where evapotranspiration remains controlled by soil moisture, and weakening where evapotranspiration depends on atmospheric demand. In SON, the atmospheric influence is weaker, but soil memory helps to maintain the coupling between soil moisture and evapotranspiration and the relocation of the hot spot at high resolution. The multimodel agreement provides robust evidence that atmospheric dynamics determines the onset of land–atmosphere interactions, while the soil state modulates their duration. Comparison of precipitation, soil moisture, and evapotranspiration against satellite data reveals that the enhanced moistening at high resolution significantly reduces model biases, supporting the realism of the hot-spot relocation. © 2021 American Meteorological Society.
英文关键词	Digital storage; Evapotranspiration; Moisture control; African easterly jet; African easterly waves; Atmospheric conditions; Atmospheric dynamics; Coupling sensitivity; Different resolutions; Horizontal wind shear; Large-scale circulation; Soil moisture
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/170930
作者单位	National Centre for Atmospheric Science, Reading, United Kingdom; Department of Meteorology, University of Reading, Reading, United Kingdom; European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom; Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands; The Ocean in the Earth System, Max Planck Institute for Meteorology, Hamburg, Germany
推荐引用方式 GB/T 7714	Müller O.V.,Vidale P.L.,Vannière B.,等. Land–Atmosphere Coupling Sensitivity to GCMs Resolution: A Multimodel Assessment of Local and Remote Processes in the Sahel Hot Spot[J],2021,34(3).
APA	Müller O.V..,Vidale P.L..,Vannière B..,Schiemann R..,Senan R..,...&Jungclaus J.H..(2021).Land–Atmosphere Coupling Sensitivity to GCMs Resolution: A Multimodel Assessment of Local and Remote Processes in the Sahel Hot Spot.Journal of Climate,34(3).
MLA	Müller O.V.,et al."Land–Atmosphere Coupling Sensitivity to GCMs Resolution: A Multimodel Assessment of Local and Remote Processes in the Sahel Hot Spot".Journal of Climate 34.3(2021).