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Fourth-Order Conservative Transport on Overset Grids Using Multi-Moment Constrained Finite Volume Scheme for Oceanic Modeling

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Journal of Ocean University of China 2020年第4期19卷 747-760页

作者： GU Juan PENG Xindong dai yongjiu CHE Yuzhang College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China College of Air Traffic Management Civil Aviation Flight University of ChinaGuanghan 618307China School of Atmospheric Sciences Sun Yat-Sen UniversityGuangzhou 510275China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information TechnologyChengdu 610103China Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan

With an increase in model resolution,compact high-order numerical advection scheme can improve its effectiveness and competitiveness in oceanic modeling due to its high accuracy and scalability on massive-processor *** provide high-quality numerical ocean simulation on overset grids,we tried a novel formulation of the fourth-order multi-moment constrained finite volume scheme to simulate continuous and discontinuous problems in the Cartesian *** some degrees of freedom over each cell and derivatives at the cell center,we obtained a two-dimensional(2D)cubic polynomial from which point values on the extended overlap can achieve fourth-order ***,this interpolation causes a lack of conservation because the flux between the regions are no longer equal;thus,a flux correction is implemented to ensure conservation.A couple of numerical experiments are presented to evaluate the numerical scheme,which confirms its approximately fourth-order accuracy in conservative transportation on overset *** test cases reveal that the scheme is effective to suppress numerical oscillation in discontinuous problems,which may be powerful for salinity advection computing with a sharp gradient.

关键词： multi-moment constrained finite volume scheme oceanic modeling overset grid conservation numerical transport

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Coupling the Common Land Model to ECHAM5 Atmospheric General Circulation Model

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Journal of Meteorological Research 2019年第2期33卷 251-263页

作者： Yufei XIN yongjiu dai Jian LI Xinyao RONG Guo ZHANG State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences China Meteorological Administration School of Atmospheric Sciences Sun Yat-Sen University

The ECHAM5 model is coupled with the widely used Common Land Model(CoLM). ECHAM5 is a state-of-theart atmospheric general circulation model incorporated into the integrated weather and climate model of the Chinese Academy of Meteorological Sciences(CAMS-CSM). Land surface schemes in ECHAM5 are simple and do not provide an adequate representation of the vegetation canopy and snow/frozen soil processes. Two AMIP(Atmospheric Model Intercomparison Project)-type experiments using ECHAM5 and ECHAM5-CoLM are run over 30 yr and the results are compared with reanalysis and observational data. It is found that the pattern of land surface temperature simulated by ECHAM5-CoLM is significantly improved relative to ECHAM5. Specifically, the cold bias over Eurasia is removed and the root-mean-square error is reduced in most regions. The seasonal variation in the zonal mean land surface temperature and the in situ soil temperature at 20-and 80-cm depths are both better simulated by ECHAM5-CoLM. ECHAM5-CoLM produces a more reasonable spatial pattern in the soil moisture content, whereas ECHAM5 predicts much drier soils. The seasonal cycle of soil moisture content from ECHAM5-CoLM is a better match to the observational data in six specific regions. ECHAM5-CoLM reproduces the observed spatial patterns of both sensible and latent heat fluxes. The strong positive bias in precipitation over land is reduced in ECHAM5-CoLM, especially over the southern Tibetan Plateau and middle–lower reaches of the Yangtze River during the summer monsoon rainy season.

关键词： atmospheric general circulation models ECHAM5 Common Land Model land-atmosphere coupling

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A 3D Nonhydrostatic Compressible Atmospheric Dynamic Core by Multi-moment Constrained Finite Volume Method

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Advances in Atmospheric Sciences 2019年第10期36卷 1129-1142页

作者： Qingchang QIN Xueshun SHEN Chungang CHEN Feng XIAO yongjiu dai Xingliang LI College of Global Change and Earth System Science Beijing Normal University Beijing 100875 China Center of Numerical Weather Predication China Meteorological Administration Beijing 100081 China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong University Xi’an 710049 China Department of Mechanical Engineering Tokyo Institute of Technology Tokyo 226-8502 Japan School of Atmospheric Sciences Sun Yat-Sen University Guangzhou 510275 China Beijing Meteorological Observatory Beijing 100089 China

A 3D compressible nonhydrostatic dynamic core based on a three-point multi-moment constrained finite-volume (MCV) method is developed by extending the previous 2D nonhydrostatic atmospheric dynamics to 3D on a terrainfollowing grid. The MCV algorithm defines two types of moments: the point-wise value (PV) and the volume-integrated average (VIA). The unknowns (PV values) are defined at the solution points within each cell and are updated through the time evolution formulations derived from the governing equations. Rigorous numerical conservation is ensured by a constraint on the VIA moment through the flux form formulation. The 3D atmospheric dynamic core reported in this paper is based on a three-point MCV method and has some advantages in comparison with other existing methods, such as uniform third-order accuracy, a compact stencil, and algorithmic simplicity. To check the performance of the 3D nonhydrostatic dynamic core, various benchmark test cases are performed. All the numerical results show that the present dynamic core is very competitive when compared to other existing advanced models, and thus lays the foundation for further developing global atmospheric models in the near future.

关键词： multi-moment constrained finite-volume method nonhydrostatic dynamic core topography height-based terrain-following coordinate

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Global and regional soil organic carbon estimates:Magnitudes and uncertainties

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Pedosphere 2024年第4期34卷 685-698页

作者： Ziqi LIN yongjiu dai Umakant MISHRA Guocheng WANG Wei SHANGGUAN Wen ZHANG Zhangcai QIN School of Atmospheric Sciences Guangdong Province Key Laboratory for Climate Change and Natural Disaster StudiesSun Yat-sen UniversityZhuhai 519082China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China Computational Biology&Biophysics Sandia National LaboratoriesLivermore CA 94550USA Faculty of Geographical Science Beijing Normal UniversityBeijing 100875China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Globally,soil is the largest terrestrial carbon(C)*** quantification of soil organic C(SOC)stocks in existing global observation-based estimates avails accurate predictions in carbon-climate feedbacks and future climate *** investigated the magnitudes and distributions of global and regional SOC estimates(i.e.,density and stocks)based on five widely used global gridded SOC datasets,a regional permafrost dataset developed in 2021(UM2021),and a global-scale soil profile database(World Soil Information Service)reporting measurements of a series of physical and chemical edaphic *** five global gridded SOC datasets were the Harmonized World Soil Database(HWSD),World Inventory of Soil Emission Potentials at 30 arc-second resolution(WISE30sec),Global Soil Dataset for Earth System Models(GSDE),Global Gridded Soil Information at 250-m resolution(SoilGrids250m),and Global Soil Organic Carbon Map(GSOCmap).Our analyses showed that the magnitude and distribution of SOC varied widely among datasets,with certain datasets showing region-specific *** the global scale,SOC stocks at the top 30 and 100 cm were estimated to be 828(range:577–1171)and 1873(range:1086–2678)Pg C,*** estimates from GSDE,GSOCmap,and WISE30sec were comparable,and those of SoilGrids250m and HWSD were at the upper and lower *** spatial SOC distribution varied greatly among datasets,especially in the northern circumpolar and Tibetan Plateau permafrost ***,UM2021 and WISE30sec performed well in the northern circumpolar permafrost regions,and GSDE performed well in *** estimates of SOC by different datasets also showed large variabilities across different soil layers and *** discrepancies were generally smaller for the 0–30 cm soil than the 0–100 cm *** datasets demonstrated relatively higher agreement in grasslands,croplands,and shrublands/savannas than in other biomes(e.g.,wetlands).The users should be mindful of the gaps b

关键词： biome carbon cycle Earth System Models permafrost region soil dataset soil map

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Changes in Global Vegetation Distribution and Carbon Fluxes in Response to Global Warming:Simulated Results from IAP-DGVM in CAS-ESM2

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Advances in Atmospheric Sciences 2022年第8期39卷 1285-1298,I0002-I0010页

作者： Xiaofei GAO Jiawen ZHU Xiaodong ZENG Minghua ZHANG yongjiu dai Duoying JI He ZHANG International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China School of Marine and Atmospheric Sciences Stony Brook UniversityNY 11790USA School of Atmospheric Sciences Sun Yat-Sen UniversityGuangzhou 510275China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China

Terrestrial ecosystems are an important part of Earth systems,and they are undergoing remarkable changes in response to global *** study investigates the response of the terrestrial vegetation distribution and carbon fluxes to global warming by using the new dynamic global vegetation model in the second version of the Chinese Academy of Sciences(CAS)Earth System Model(CAS-ESM2).We conducted two sets of simulations,a present-day simulation and a future simulation,which were forced by the present-day climate during 1981-2000 and the future climate during 2081-2100,respectively,as derived from RCP8.5 outputs in ***_(2)concentration is kept constant in all simulations to isolate CO_(2)-fertilization *** results show an overall increase in vegetation coverage in response to global warming,which is the net result of the greening in the mid-high latitudes and the browning in the *** results also show an enhancement in carbon fluxes in response to global warming,including gross primary productivity,net primary productivity,and autotrophic *** found that the changes in vegetation coverage were significantly correlated with changes in surface air temperature,reflecting the dominant role of temperature,while the changes in carbon fluxes were caused by the combined effects of leaf area index,temperature,and *** study applies the CAS-ESM2 to investigate the response of terrestrial ecosystems to climate *** though the interpretation of the results is limited by isolating CO_(2)-fertilization effects,this application is still beneficial for adding to our understanding of vegetation processes and to further improve upon model parameterizations.

关键词： global warming vegetation distribution carbon flux leaf area index surface air temperature

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Enhancing Deep Learning Soil Moisture Forecasting Models by Integrating Physics-based Models

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Advances in Atmospheric Sciences 2024年第7期41卷 1326-1341页

作者： Lu LI yongjiu dai Zhongwang WEI Wei SHANGGUAN Nan WEI Yonggen ZHANG Qingliang LI Xian-Xiang LI School of Atmospheric Sciences Sun Yat-sen UniversityGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Guangzhou 510275China Institute of Surface-Earth System Science School of Earth System ScienceTianjin UniversityTianjin 300072China College of Computer Science and Technology Changchun Normal UniversityChangchun 130123China

Accurate soil moisture(SM)prediction is critical for understanding hydrological ***-based(PB)models exhibit large uncertainties in SM predictions arising from uncertain parameterizations and insufficient representation of land-surface *** addition to PB models,deep learning(DL)models have been widely used in SM predictions ***,few pure DL models have notably high success rates due to lacking physical ***,we developed hybrid models to effectively integrate the outputs of PB models into DL models to improve SM *** this end,we first developed a hybrid model based on the attention mechanism to take advantage of PB models at each forecast time scale(attention model).We further built an ensemble model that combined the advantages of different hybrid schemes(ensemble model).We utilized SM forecasts from the Global Forecast System to enhance the convolutional long short-term memory(ConvLSTM)model for 1–16 days of SM *** performances of the proposed hybrid models were investigated and compared with two existing hybrid *** results showed that the attention model could leverage benefits of PB models and achieved the best predictability of drought events among the different hybrid ***,the ensemble model performed best among all hybrid models at all forecast time scales and different soil *** is highlighted that the ensemble model outperformed the pure DL model over 79.5%of in situ stations for 16-day *** findings suggest that our proposed hybrid models can adequately exploit the benefits of PB model outputs to aid DL models in making SM predictions.

关键词： soil moisture forecasting hybrid model deep learning ConvLSTM attention mechanism

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Evaluation of the New Dynamic Global Vegetation Model in CAS-ESM

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Advances in Atmospheric Sciences 2018年第6期35卷 659-670页

作者： Jiawen ZHU Xiaodong ZENG Minghua ZHANG yongjiu dai Duoying JI Fang LI Qian ZHANG He ZHANG Xiang SONG International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and Technology School of Marine and Atmospheric Sciences Stony Brook University School of Atmospheric Sciences Sun Yat-Sen University College of Global Change and Earth System Science Beijing Normal University

In the past several decades, dynamic global vegetation models（DGVMs） have been the most widely used and appropriate tool at the global scale to investigate vegetation-climate interactions. At the Institute of Atmospheric Physics, a new version of DGVM（IAP-DGVM） has been developed and coupled to the Common Land Model（CoLM） within the framework of the Chinese Academy of Sciences＇ Earth System Model（CAS-ESM）. This work reports the performance of IAP-DGVM through comparisons with that of the default DGVM of CoLM（CoLM-DGVM） and observations. With respect to CoLMDGVM, IAP-DGVM simulated fewer tropical trees, more ＂needleleaf evergreen boreal tree＂ and ＂broadleaf deciduous boreal shrub＂, and a better representation of grasses. These contributed to a more realistic vegetation distribution in IAP-DGVM,including spatial patterns, total areas, and compositions. Moreover, IAP-DGVM also produced more accurate carbon fluxes than CoLM-DGVM when compared with observational estimates. Gross primary productivity and net primary production in IAP-DGVM were in better agreement with observations than those of CoLM-DGVM, and the tropical pattern of fire carbon emissions in IAP-DGVM was much more consistent with the observation than that in CoLM-DGVM. The leaf area index simulated by IAP-DGVM was closer to the observation than that of CoLM-DGVM; however, both simulated values about twice as large as in the observation. This evaluation provides valuable information for the application of CAS-ESM, as well as for other model communities in terms of a comparative benchmark.

关键词： vegetation dynamics dynamic global vegetation model vegetation distribution carbon flux leaf area index

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Mapping Near-surface Air Temperature, Pressure, Relative Humidity and Wind Speed over China's Mainland with High Spatiotemporal Resolution

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Advances in Atmospheric Sciences 2014年第5期31卷 1127-1135页

作者： LI Tao ZHENG Xiaogu dai yongjiu YANG Chi CHEN Zhuoqi ZHANG Shupeng WU Guocan WANG Zhonglei HUANG Chengcheng SHEN Yan LIAO Rongwei College of Global Change and Earth System Science Beijing Normal University National Meteorological Information Center China Meteorological Administration

As part of a joint effort to construct an atmospheric forcing dataset for China's Mainland with high spatiotemporal reso- lution, a new approach is proposed to construct gridded near-surface temperature, relative humidity, wind speed and surface pressure with a resolution of 1 km× 1 km. The approach comprises two steps：（1） fit a partial thin-plate smoothing spline with orography and reanalysis data as explanatory variables to ground-based observations for estimating a trend surface; （2） apply a simple kriging procedure to the residual for trend surface correction. The proposed approach is applied to observations collected at approximately 700 stations over China's Mainland. The generated forcing fields are compared with the corresponding components of the National Centers for Environmental Predic- tion （NCEP） Climate Forecast System Reanalysis dataset and the Princeton meteorological forcing dataset. The comparison shows that, both within the station network and within the resolutions of the two gridded datasets, the interpolation errors of the proposed approach are markedly smaller than the two gridded datasets.

关键词： atmospheric forcing data land surface model thin-plate smoothing spline kriging reanalysis data

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Assessment of global meteorological,hydrological and agricultural drought under future warming based on CMIP6

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Atmospheric and Oceanic Science Letters 2022年第1期15卷 49-55页

作者： Jianxin Zeng Jiaxian Li Xingjie Lu Zhongwang Wei Wei Shangguan Shupeng Zhang yongjiu dai Shulei Zhang Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangdong Province Key Laboratory for Climate Change and Natural Disaster StudiesSchool of Atmospheric SciencesSun Yat-sen UniversityGuangzhouChina

Quantifying the changes and propagation of drought is of great importance for regional eco-environmental safety and water-related disaster management under global *** this study,phase 6 of the Coupled Model Intercomparison Project was employed to examine future meteorological(Standardized Precipitation Index,SPI,and Standardized Precipitation-Evapotranspiration Index,SPEI),hydrological(Standardized Runoff Index,SRI),and agricultural(Standardized Soil moisture Index,SSI) drought under two warming scenarios(SSP2-4.5 and SSP5-8.5).The results show that,across the globe,different types of drought events generally exhibit a larger spatial extent,longer duration,and greater severity from 1901 to 2100,with SPEI drought experiencing the greatest *** SRI and SSI drought are expected to be more intensifying than SPI drought,the models show higher consistency in projections of SPI *** with robust drying trends include the southwestern United States,Amazon Basin,Mediterranean,southern Africa,southern Asia,and *** is also found that meteorological drought shows a higher correlation with hydrological drought than with agricultural drought,especially in warm and humid ***,the maximum correlation between meteorological and hydrological drought tends to be achieved at a short time *** findings have important implications for drought monitoring and policy interventions for water resource management under a changing climate.

关键词： Climate change Meteorological drought Hydrological drought Agricultural drought Drought propagation CMIP6

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Preliminary estimation of the organic carbon pool in China's wetlands

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Chinese Science Bulletin 2013年第2期58卷 662-670页

作者： ZHENG YaoMin NIU ZhenGuo GONG Peng dai yongjiu SHANGGUAN Wei State Key Laboratory of Remote Sensing Science Jointly Sponsored by Institute of Remote Sensing ApplicationsChinese Academy Sciences and Beijing Normal University Ministry of Education Key Laboratory for Earth System Modeling Center for Earth System ScienceInstitute for Global Change StudiesTsinghua University Department of Environmental Science Policy and ManagementUniversity of California College of Global Change and Earth System Science Beijing Normal University

Accurate estimation of wetland carbon pools is a prerequisite for wetland resource conservation and implementation of carbon sink enhancement *** inventory approach is a realistic method for estimating the organic carbon pool in China's wetlands at the national *** updated data and inventory approach were used to estimate the amount of organic carbon stored in China's *** results are as follows:(1) the organic carbon pool of China's wetlands is between 5.39 and 7.25 Pg,accounting for 1.3%-3.5% of the global level;(2) the estimated values and percentages of the organic carbon contained in the soil,water and vegetation pools in China's wetlands are 5.04-6.19 Pg and 85.4%-93.5%,0.22-0.56 Pg and 4.1%-7.7%,0.13-0.50 Pg and 2.4%-6.9%,*** soil organic carbon pool of China's wetlands is greater than our previous estimate of 3.67 Pg,but is lower than other previous estimates of 12.20 and 8-10 *** on the discussion and uncertainty analysis,some research areas worthy of future attention are presented.

关键词：土壤有机碳库湿地资源中国估算不确定性分析模估计交流计数湿地土壤

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