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Autumn Snow Cover Variability over Northern Eurasia and Roles of Atmospheric Circulation

Advances in Atmospheric Sciences 2017年第7期34卷 847-858页

作者： Kunhui YE Renguang WU Institute of Space and Earth Information Science The Chinese University of Hong Kong Hong Kong China Center for Monsoon System Research/State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

This study analyzes the variability of northern Eurasian snow cover（SC） in autumn and the impacts of atmospheric circulation changes. The region of large SC variability displays a southward shift from September to November, following the seasonal progression of the transition zones of surface air temperature（SAT）. The dominant pattern of SC variability in September and October features a zonal distribution, and that in November displays an obvious west-east contrast. Surface air cooling and snowfall increase are two factors for larger SC. The relative contribution of SAT and snowfall changes to SC, however, varies with the region and depends upon the season. The downward longwave radiation and atmospheric heat advection play important roles in SAT changes. Anomalous convergence of water vapor flux contributes to enhanced *** changes in downward longwave radiation are associated with those in atmospheric water content and column *** in snowfall and the transport of atmospheric moisture determine the atmospheric moisture content in September and October, and the snowfall appears to be a main factor for atmospheric moisture change in November. These results indicate that atmospheric circulation changes play an important role in snow variability over northern Eurasia in autumn. Overall, the coupling between autumn Eurasian snow and atmospheric circulation may not be driven by external forcing.

关键词： Autumn Eurasian snow cover surface air temperature surface heat fluxes atmospheric circulation water vaportransport

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Differences and Links between the East Asian and South Asian Summer Monsoon systems:Characteristics and Variability

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Advances in Atmospheric Sciences 2017年第10期34卷 1204-1218页

作者： Ronghui HUANG Yong LIU Zhencai DU Jilong CHEN Jingliang HUANGFU Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100190China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of ScienceBeijing 100029China Institute of Earth Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper analyzes the differences in the characteristics and spatio–temporal variabilities of summertime rainfall and water vapor transport between the East Asian summer monsoon（EASM） and South Asian summer monsoon（SASM） systems. The results show obvious differences in summertime rainfall characteristics between these two monsoon systems. The summertime rainfall cloud systems of the EASM show a mixed stratiform and cumulus cloud system, while cumulus cloud dominates the SASM. These differences may be caused by differences in the vertical shear of zonal and meridional circulations and the convergence of water vapor transport fluxes. Moreover, the leading modes of the two systems＇ summertime rainfall anomalies also differ in terms of their spatiotemporal features on the interannual and interdecadal timescales. Nevertheless, several close links with respect to the spatiotemporal variabilities of summertime rainfall and water vapor transport exist between the two monsoon systems. The first modes of summertime rainfall in the SASM and EASM regions reveal a significant negative correlation on the interannual and the interdecadal timescales. This close relationship may be linked by a meridional teleconnection in the regressed summertime rainfall anomalies from India to North China through the southeastern part over the Tibetan Plateau, which we refer to as the South Asia/East Asia teleconnection pattern of Asian summer monsoon rainfall. The authors wish to dedicate this paper to Prof. Duzheng YE, and commemorate his 100 thanniversary and his great contributions to the development of atmospheric dynamics.

关键词： East Asian summer monsoon South Asian summer monsoon spatiotemporal variability rainfall water vapor transport

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Reducing the biases in shortwave cloud radiative forcing in tropical and subtropical regions from the perspective of boundary layer processes

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Science China earth Sciences 2016年第7期59卷 1427-1439页

作者： SUN Wen Qi LI Li Juan WANG Bin State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences Ministry of Education Key Laboratory for Earth System Modeling Center of Earth System Science Tsinghua University

Biases in shortwave cloud radiative forcing(SWCF), which cause overestimates in tropical regions and underestimates in subtropical marine stratocumulus regions, are common in many climate models. Here, two boundary layer processes are investigated in the atmospheric model GAMIL2, entrainment at the top of the boundary layer and longwave radiative cooling at the top of stratocumulus clouds, in order to reduce biases and reveal the mechanisms underlying these processes. Our results show that including the entrainment process in the model can reduce negative SWCF biases in most tropical regions but increases positive SWCF biases in subtropical marine stratocumulus regions. This occurs because entrainment reduces the low-level cloud fraction and its cloud liquid water content by suppressing the vertical turbulent diffusion in the boundary layer and decreasing the relative humidity when warm and dry free atmosphere is entrained in the boundary layer. Longwave radiative cooling at the top of stratocumulus clouds can enhance turbulent diffusion within the stratocumulus-topped boundary layer. When combined with the entrainment process, longwave radiative cooling reduces the positive SWCF biases in subtropical marine stratocumulus regions that are observed using the entrainment process alone. The incorporation of these two boundary layer processes improves the simulated SWCF in tropical and subtropical regions in GAMIL2.

关键词： SWCF GAMIL2 Boundary layer Entrainment Stratocumulus

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Erratum to: Could the Recent Taal Volcano Eruption Trigger an El Niño and Lead to Eurasian Warming?

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Advances in Atmospheric Sciences 2020年第11期37卷 1295-1295页

作者： Liu, Fei Xing, Chen Li, Jinbao Wang, Bin Chai, Jing Gao, Chaochao Huang, Gang Liu, Jian Chen, Deliang School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Sun Yat-sen University Zhuhai China Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Zhuhai China Earth System Modeling and Climate Dynamics Research Center Nanjing University of Information Science and Technology Nanjing China Department of Geography University of Hong Kong Pokfulam Hong Kong Department of Atmospheric Sciences and International Pacific Research Center University of Hawaii at Manoa Honolulu USA Department of Environmental Science Zhejiang University Hangzhou China State key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Key Laboratory for Virtual Geographic Environment Ministry of Education Jiangsu Provincial State Key Laboratory Cultivation Base of Geographical Environment Evolution School of Geography Science Nanjing Normal University Nanjing China Department of Earth Sciences University of Gothenburg Gothenburg Sweden

In the third column of the five row of Table 1, “120.4°W” should be “20.4°E”.

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Decadal Indian Ocean Dipolar Variability and Its Relationship with the Tropical Pacific

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Advances in Atmospheric Sciences 2017年第11期34卷 1282-1289页

作者： Yun YANG Jianping LI Lixin WU Yu KOSAKA Yan DU Cheng SUN Fei XIE Juan FENG State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technologyqingdao 266237China Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology Ocean University of Chinaqingdao 266003China Research Center for Advanced Science and Technology University of TokyoTokyo153-8904Japan State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of Sciencesguangzhou 510301China

A robust decadal Indian Ocean dipolar variability （DIOD） is identified in observations and found to be related to tropical Pacific decadal variability （TPDV）. A Pacific Ocean-global atmosphere （POGA） experiment, with fixed radiative forcing, is conducted to evaluate the DIOD variability and its relationship with the TPDV. In this experiment, the sea surface temperature anomalies are restored to observations over the tropical Pacific, but left as interactive with the atmosphere elsewhere. The TPDV-forced DIOD, represented as the ensemble mean of 10 simulations in POGA, accounts for one third of the total variance. The forced DIOD is triggered by anomalous Walker circulation in response to the TPDV and develops following Bjerknes feedback. Thermocline anomalies do not exhibit a propagating signal, indicating an absence of oceanic planetary wave adjustment in the subtropical Indian Ocean. The DIOD-TPDV correlation differs among the 10 simulations, with a low correlation corresponding to a strong internal DIOD independent of the TPDV. The variance of this internal DIOD depends on the background state in the Indian Ocean, modulated by the thermocline depth off Sumatra/Java.

关键词： Indian Ocean dipole decadal variability tropical Pacific decadal variability

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Degradable film mulching increases soil carbon sequestration in major Chinese dryland agroecosystems

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Nature communications 2025年第1期16卷 5029页

作者： Zihan Liu Chenxu Zhao Nanhai Zhang Jing Wang Zhaoyang Li Yves Uwiragiye Nyumah Fallah Thomas W Crowther Yuanyuan Huang Yi Xu Sheng Zhang Yakov Kuzyakov Kadambot H M Siddique Zhikuan Jia Zucong Cai Scott X Chang Minggang Xu Christoph Müller Yi Cheng School of Geography Nanjing Normal University 210023 Nanjing China. College of Agronomy Northwest A&F University 712100 Yangling China. Co-Innovation Center for Sustainable Forestry in Southern China College of Forestry Nanjing Forestry University 210037 Nanjing China. Department of Environmental Systems Science Institute of Integrative Biology ETH Zurich Zurich 8092 Switzerland. Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China. College of Agronomy and Biotechnology China Agricultural University 100193 Beijing China. Geo-Biosphere Interactions Department of Geosciences University of Tübingen Tübingen 72076 Germany. Institute of Soil Science Chinese Academy of Sciences 210008 Nanjing China. Department of Soil Science of Temperate Ecosystems Department of Agricultural Soil Science University of Göttingen Göttingen 37077 Germany. Peoples Friendship University of Russia (RUDN University) Moscow 117198 Russia. The UWA Institute of Agriculture The University of Western Australia Perth WA 6001 Australia. College of Agronomy Northwest A&F University 712100 Yangling China. jiazhk@***. Department of Renewable Resources University of Alberta Edmonton AB T6G 2E3 Canada. Shanxi Province Key Laboratory of Soil Environment and Nutrient Resources Engineer and Technology Academy of Ecology and Environment Shanxi Agricultural University 030031 Taiyuan China. State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China Key Laboratory of Arable Land Quality Monitoring and Evaluation Ministry of Agriculture and Rural Affairs Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences 100081 Beijing China. Liebig Centre of Agroecology and Climate Impact Research Justus Liebig University Giessen Giessen 35392 Germany. Institute of Plant Ecology Justus Liebig Univer

Plastic film mulching (PM), which contributes to nearly half of the increased crop yields in dryland agroecosystems, exacerbates environmental burdens due to its non-degradable nature. Globally, there is a growing demand to replace non-degradable PM with degradable film mulching (DM), yet its impacts on soil organic carbon (SOC) in dryland agroecosystems remains unknown. Here, using multi-field studies and mesocosm experiments, we found that DM strongly increased but PM reduced SOC storage (0-1 m). This difference is likely attributable to the higher microbial C use efficiency in soil under DM, leading to increased microbial-derived C compared to PM. Under the high roading scenario for 2100, DM could reduce the decomposition of SOC (0-1 m) in China's drylands by 9.0 ± 1.0 Mg ha year (one standard error) compared with PM. Our findings highlight that DM is a promising alternative to PM for sequestrating SOC and alleviating C loss under climate change in dryland agroecosystems.

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Quantifying local predictability of the Lorenz system using the nonlinear local Lyapunov exponent

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Atmospheric and Oceanic Science Letters 2017年第5期10卷 372-378页

作者： HUAI Xiao-Wei LI Jian-Ping DING Rui-Qiang FENG Jie LIU De-Qiang State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric PhysicsChinese Academy of Sciences Beijing China College of Earth Science University of Chinese Academy of Sciences Beijing China College of Global Change and Earth System Science (GCESS) Beijing Normal University Beijing China Joint Center for Global Change Studies Beijing Normal University Beijing China College of Atmospheric Sciences Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology Chengdu China GIobal Systems Division Earth System Research Laboratory/Oceanic and Atmospheric Research/National Oceanic and Atmospheric Administration Boulder CO USA Fujian Meteorological Observatory Fuzhou China

The nonlinear local Lyapunov exponent（NLLE） can be used as a quantification of the local predictability limit of chaotic systems. In this study, the phase-spatial structure of the local predictability limit over the Lorenz-63 system is investigated. It is found that the inner and outer rims of each regime of the attractor have a high probability of a longer than average local predictability limit, while the center part is the opposite. However, the distribution of the local predictability limit is nonuniformly organized, with adjacent points sometimes showing quite distinct error *** source of local predictability is linked to the local dynamics, which is related to the region in the phase space and the duration on the current regime.

关键词： Nonlinear local Lyapunov exponent local predictability limit chaotic system Lorenz system

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Characteristics of pressure gradient force errors in a terrain-following coordinate

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Atmospheric and Oceanic Science Letters 2016年第3期9卷 211-218页

作者： LI Jin-Xi LI Yi-Yuan WANG Bin State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences Ministry of Education Key Laboratory for Earth System Modeling and Center for Earth System Science Tsinghua University

A terrain-following coordinate （a-coordinate） in which the computational form of pressure gradient force （PGF） is two-term （the so-called classic method） has significant PGF errors near steep terrain. Using the covariant equations of the a-coordinate to create a one-term PGF （the covariant method） can reduce the PGF errors. This study investigates the factors inducing the PGF errors of these two methods, through geometric analysis and idealized experiments. The geometric analysis first demonstrates that the terrain slope and the vertical pressure gradient can induce the PGF errors of the classic method, and then generalize the effect of the terrain slope to the effect of the slope of each vertical layer （φ）. More importantly, a new factor, the direction of PGF （a）, is proposed by the geometric analysis, and the effects of φ and a are quantified by tan φ.tan a. When tan φ.tan a is greater than 1/9 or smaller than -10/9, the two terms of PGF of the classic method are of the same order but opposite in sign, and then the PGF errors of the classic method are large. Finally, the effects of three factors on inducing the PGF errors of the classic method are validated by a series of idealized experiments using various terrain types and pressure fields. The experimental results also demonstrate that the PGF errors of the covariant method are affected little by the three factors.

关键词： Terrain-following coordinatepressure gradient forceerrors direction of pressuregradient slope of eachvertical layer nonlinearvertical pressure gradient pressure gradient alongvertical layer

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Pressure gradient errors in a covariant method of implementing theσ-coordinate:idealized experiments and geometric analysis

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Atmospheric and Oceanic Science Letters 2016年第4期9卷 270-276页

作者： LI Jin-Xi LI Yi-Yuan WANG Bin State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina College of Earth Science University of Chinese Academy of SciencesBeijingChina Ministry of Education Key Laboratory for Earth System Modeling and Center for Earth System ScienceTsinghua UniversityBeijingChina

A new approach is proposed to use the covariant scalar equations of the a-coordinate （the covariant method）, in which the pressure gradient force （PGF） has only one term in each horizontal momentum equation, and the PGF errors are much reduced in the computational space. In addition, the validity of reducing the PGF errors by this covariant method in the computational and physical space over steep terrain is investigated. First, the authors implement a set of idealized experiments of increasing terrain slope to compare the PGF errors of the covariant method and those of the classic method in the computational space. The results demonstrate that the PGF errors of the covariant method are consistently much-reduced, compared to those of the classic method. More importantly, the steeper the terrain, the greater the reduction in the ratio of the PGF errors via the covariant method. Next, the authors use geometric analysis to further investigate the PGF errors in the physical space, and the results illustrates that the PGF of the covariant method equals that of the classic method in the physical space; namely, the covariant method based on the non-orthogonal a-coordinate cannot reduce the PGF errors in the physical space. However, an orthogonal method can reduce the PGF errors in the physical space. Finally, a set of idealized experiments are carried out to validate the results obtained by the geometric analysis. These results indicate that the covariant method may improve the simulation of variables relevant to pressure, in addition to pressure itself, near steep terrain.

关键词： Pressure gradient forceerrors covariant scalarequations of the o-coordinate steep terrain computational andphysical space geometricanalysis non-orthogonala-coordinate

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Assessment of Interannual Sea Surface Salinity Variability and Its Effects on the Barrier Layer in the Equatorial Pacific Using BNU-ESM

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Advances in Atmospheric Sciences 2016年第3期33卷 339-351页

作者： Hai ZHI Rong-Hua ZHANG Fei ZHENG Pengfei LIN Lanning WANG Peng YU Earth System Modeling Center and College of Atmospheric Sciences Nanjing University of Information Science and Technology Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences International Center for Climate and Environment Science Institute of Atmospheric PhysicsChinese Academy of Sciences State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences College of Global Change and Earth System Science Beijing Normal University Cooperative Institute for Climate and Satellites University of MarylandCollege Park

As salinity stratification is necessary to form the barrier layer （BL）, the quantification of its role in BL interannual variability is crucial. This study assessed salinity variability and its effect on the BL in the equatorial Pacific using outputs from Beijing Normal University earth system Model （BNU-ESM） simulations. A comparison between observations and the BNU-ESM simulations demonstrated that BNU-ESM has good capability in reproducing most of the interannual features observed in nature. Despite some discrepancies in both magnitude and location of the interannual variability centers, the displacements of sea surface salinity （SSS）, barrier layer thickness （BLT）, and SST simulated by BNU-ESM in the equatorial Pacific are realistic. During E1 Nifio, for example, the modeled interannual anomalies of BLT, mixed layer depth, and isothermal layer depth, exhibit good correspondence with observations, including the development and decay of E1 Nifio in the central Pacific, whereas the intensity of the interannual variabilities is weaker relative to observations. Due to the bias in salinity simulations, the SSS front extends farther west along the equator, whereas BLT variability is weaker in the central Pacific than in observations. Further, the BNU-ESM simulations were examined to assess the relative effects of salinity and temperature variability on BLT. Consistent with previous observation-based analyses, the interannual salinity variability can make a significant contribution to BLT relative to temperature in the western-central equatorial Pacific.

关键词： feedback interannual variability sea surface salinity barrier layer thickness

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