气候变化领域集成服务门户(CCPortal): Diagnosing Mixing Properties in Model Simulations for CH4 in the Stratosphere

CCPortal

DOI	10.1029/2020JD032524
	Diagnosing Mixing Properties in Model Simulations for CH4 in the Stratosphere
	Wang Z.; Hase N.; Notholt J.; Dils B.; Saunois M.; Warneke T.; Tian W.
发表日期	2020
ISSN	2169897X
卷号	125 期号:15
英文摘要	Isentropic mixing properties in the stratosphere modeled by the forward calculation of an inverse model (TM5-4DVAR) are evaluated against Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and Microwave Limb Sounder (MLS) observations. The isentropic mixing processes are separated into large-scale stirring described by the “equivalent length” and small-scale diffusion described by the diffusivity. Compared to the measurements, we find that the modeled stirring is not strong enough and that the small-scale diffusivity is too large. TM5-4DVAR produces excessive mixing-induced poleward flux for stratospheric CH4. The flux convergence presents negative biases in the tropics and positive biases in the polar regions. The biases cannot be reduced by improving the horizontal resolution only. Modeled isentropic mixing depends on the horizontal as well as the vertical resolution of the model. An increase in vertical resolution reduces numerical diffusion of the model in the vertical. The decreased vertical diffusion leads to reduction in the modeled isentropic diffusivity. Biases in modeled total column-averaged mixing ratios of CH4 are significant for both models with a coarse vertical resolution of 4° × 6° × 25 (and 2° × 3° × 25, 1° × 1° × 25) and an improved one of 1° × 1° × 40. They are estimated to be 7–14 and 3–7 ppb in the winter extratropics under the assumption that isentropic mixing is dominant over vertical transport on a time scale of 3 days. Correspondingly, resulted biases in inverted CH4 surface emissions are estimated to be 0.5–1 and 0.2–0.5 mg/m2/hr, respectively, in the extratropics. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	inverse model; stratopsheric mixing properties
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185860
作者单位	College of Atmospheric Science, Lanzhou University, Lanzhou, China; Institute of Environmental Physics, University of Bremen, Bremen, Germany; Belgian Institute for Space Aeronomy, BIRA-IASB, Brussels, Belgium; Laboratoire des Sciences du Climat et de l'Environnement, LSCE-IPSL (CEA-CNRS-UVSQ), Université Paris-Saclay, Gif-sur-Yvette, France
推荐引用方式 GB/T 7714	Wang Z.,Hase N.,Notholt J.,et al. Diagnosing Mixing Properties in Model Simulations for CH4 in the Stratosphere[J],2020,125(15).
APA	Wang Z..,Hase N..,Notholt J..,Dils B..,Saunois M..,...&Tian W..(2020).Diagnosing Mixing Properties in Model Simulations for CH4 in the Stratosphere.Journal of Geophysical Research: Atmospheres,125(15).
MLA	Wang Z.,et al."Diagnosing Mixing Properties in Model Simulations for CH4 in the Stratosphere".Journal of Geophysical Research: Atmospheres 125.15(2020).