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Chinese lockdown as aerosol reduction experiment

Advances in Climate Change Research 2021年第5期12卷 677-685页

作者： Hans VON STORCH Beate GEYER LI Yan Volker MATTHIAS Burkhardt ROCKEL Institute of Coastal Systems Helmholtz-Zentrum GeesthachtGeesthacht21502Germany Ocean University of china Qingdao266100China College of Life Sciences and Oceanography Shenzhen UniversityShenzhen518061China Institute of Biogeochemistry in Coastal Seas Helmholtz-Zentrum GeesthachtGeesthacht21502Germany

The lockdown of large parts of Chinese economy beginning in late January 2020 lead to significant regional changes of aerosol loads, which suggests a reduction of backscatter and consequently a regional warming in the following months. Using local data and a numerical experiment with a limited area model, we have examined how strong this response may have been. The observed (local and reanalysis) observations point to a warming of less than 1.0 K, the simulations to a warming of the order of 0.5 K. These numbers are uncertain, because of large-scale natural variability and an ad-hoc choice of aerosol optical depth anomaly in the simulation. Thus, the result was, in short, that there was actually a weak warming of a few tenth of degrees, while noteworthy changes in circulation or in precipitation were not detected. More specifically, we found that at selected central china stations temperatures were found to be higher than in previous two years. This warming goes with a marked diurnal signal, with a maximum warming in the early afternoon (06 UTC), weakest at night (18 UTC). This may be related to a general warming of large swaths of Asia (including Siberia, which is not related to local aerosol forcing). Indeed, also the stations outside the immediate strong lockdown region are showing warming, albeit a weaker one. Thus, the difference 2020 minus 2019/2018 may overestimate the effect. The ad-hoc series of numerical experiments indicates that the simulated changes are robust and suffer little from internal dynamical variability. In particular, the overall reduction of the aerosol optical depth does not lead to phases of larger intermittent divergence among the model simulations, irrespective of the aerosol load. Instead, the simulations with reduced anthropogenic aerosol load show more a mere locally increased temperature. This may indicate that the aerosol effect is mostly thermodynamic in all local air columns in the region.

关键词： Lockdown china Aerosol Climate

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RIVER DISCHARGE CHANGES IN THE QINGHAI-TIBET PLATEAU

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Chinese Science Bulletin 2006年第5期51卷 594-600页

作者： CAO Jianting QIN Dahe KANG Ersi LI Yuanyuan Laboratory for Climatic Studies China Meteorological Administration Beijing 100081 China General Institute for Water Resources and Hydropower Planning and Design Ministry of Water Resources Beijing 100011 China china meteorological administration Beijing 100081 China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences. Lanzhou 730000 China

Annual mean discharge data of the five large rivers in the exorheic region of the Qing- hai-Tibet Plateau from 1956 to 2000 are analyzed for trends with the Mann-Kendall nonparametric trend test. The results reveal that though in general no in- creasing trends exist in the total river discharges, significant regional differences of river discharge ex- ist, reflecting the decreasing trends of discharge in the Yellow River and the Tongtian River (upper Changjiang River), an increasing trend in Yalong River, and inverted change in the Lancang River and Yarlung Zangbo River. Based on analyses of the seasonal discharge, it is found that climatic change had a significant effect on the seasonal variation of river discharge in the Qinghai-Tibet Plateau. In spring (from March to May) the discharge increased signifi- cantly, especially in the source area of the Yellow River. Together with the analyses on data of the mean temperature in the Northern Hemisphere and climatic data within the river basins, the relationship between discharges and mean temperature of the Northern Hemisphere is explored, which indicates that there is no increase in the stream discharge in the Qinghai-Tibet Plateau with global warming. It is probably the increasing evaporation, caused by rising temperature that offsets the hydrological effect of increasing precipitation.

关键词：河流流量曼-肯德尔试验水循环青藏高原全球变暖

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Community-Level Practice Checklists for Health Protection During Cold Spells in china

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china CDC weekly 2024年第5期6卷 83-87页

作者： Jing Shang Mengzhen Zhao Zhao Liu Xiya Zhang Shiguang Miao Ishaq D.Sulaymon Wenjia Cai Institute of Urban Meteorology CMABeijingChina School of Management and Economics Beijing Institute of TechnologyBeijingChina School of Airport Economics and Management Beijing Institute of Economics and ManagementBeijingChina Department of Earth System Science Tsinghua UniversityBeijingChina Sand and Dust Storm Warning Regional Center National Center for MeteorologyJeddahSaudi Arabia Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science and TechnologyNanjing CityJiangsu ProvinceChina

Communities play a crucial role in protecting the health of vulnerable populations such as the elderly,low-income groups,and high-risk individuals during cold ***,current strategies for responding to cold spells primarily consist of programmatic policies that lack practicality,specificity,and detailed implementation guidelines for community ***,this study aims to identify and analyze the challenges faced by communities in responding to cold spells,review international experiences,and develop a set of practical checklists for community-level health *** checklists will assist community workers and volunteers in effectively preparing for,responding to,and recovering from cold spells.

关键词： preparing income primarily

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Retrieving Atmospheric Temperature Profiles from AMSU-A Data with Neural Networks

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Advances in Atmospheric Sciences 2005年第4期22卷 606-616页

作者：姚志刚陈洪滨林龙福 Institute of Meteorology PLA University of Science and Technology Nanjing 211101 Beijing Institute of Applied Meteorology Beijing 100029 Lab for Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Beijing Institute of Applied Meteorology Beijing 100029

Back propagation neural networks are used to retrieve atmospheric temperature profiles from NOAA-16 Advanced Microwave Sounding Unit-A (AMSU-A) measurements over East Asia. The collocated radiosonde observation and AMSU-A data over land in 2002-2003 are used to train the network, and the data over land in 2004 are used to test the network. A comparison with the multi-linear regression method shows that the neural network retrieval method can significantly improve the results in all weather conditions. When an offset of 0.5 K or a noise level of ±0.2 K is added to all channels simultaneously, the increase in the overall root mean square (RMS) error is less than 0.1 K. Furthermore, an experiment is conducted to investigate the effects of the window channels on the retrieval. The results indicate that the brightness temperatures of window channels can provide significantly useful information on the temperature retrieval near the surface. Additionally, the RMS errors of the profiles retrieved with the trained neural network are compared with the errors from the International Advanced TOVS (ATOVS) Processing Package (IAPP). It is shown that the network-based algorithm can provide much better results in the experiment region and comparable results in other regions. It is also noted that the network can yield remarkably better results than IAPP at the low levels and at about the 250-hPa level in summer skies over ocean. Finally, the network-based retrieval algorithm developed herein is applied in retrieving the temperature anomalies of Typhoon Rananim from AMSU-A data.

关键词： AMSU-A neural network temperature profiles retrieval

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Improvement of Surface Albedo Simulations over Arid Regions

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Advances in Atmospheric Sciences 2008年第3期25卷 481-488页

作者：鲍艳吕世华张宇孟宪红杨胜朋 Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of SciencesLanzhou 730000

To improve the simulation of the surface radiation budget and related thermal processes in arid regions, three sophisticated surface albedo schemes designed for such regions were incorporated into the Biosphere- Atmosphere Transfer Scheme （BATS）. Two of these schemes are functions of the solar zenith angle （SZA）, where the first one has one adjustable parameter defined as SZA1 scheme, and the second one has two empirical parameters defined as SZA2 scheme. The third albedo scheme is a function of solar angle and soil water that were developed based on arid-region observations from the Dunhuang field experiment （DHEX）（defined as DH scheme）. We evaluated the performance of the original and newly-incorporated albedo schemes within BATS using the in-situ data from the Oasis System Energy and Water Cycle Field Experiment that was carried out in JinTa, Gansu arid area （JTEX）. The results indicate that a control run by the original version of the BATS generates a constant albedo, while the SZA1 and SZA2 schemes basically can reproduce the observed diurnal cycle of surface albedo, although these two schemes still underestimate the albedo when SZA is high in the early morning and late afternoon, and overestimate it when SZA is low during noontime. The SZA2 scheme has a better overall performance than the SZA1 scheme. In addition, BATS with the DH scheme slightly improves the albedo simulation in magnitude as compared to that from the control run, but a diurnal cycle of albedo is not produced by this scheme. The SZA1 and SZA2 schemes significantly increase the surface absorbed solar radiation by nearly 70 W m^-2, which further raises the ground temperature by 6 K and the sensible heat flux by 35 W m^-2. The increased solar radiation, heat flux, and temperature are more consistent with the observations that those from the control run. However, a significant improvement in these three variables is not found in BATS with the DH scheme due to the neglect of the diurnal cycle of a

关键词： arid region bare soil surface albedo solar zenith angle (SZA) BATS

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Impacts of Upper Tropospheric Cooling upon the Late Spring Drought in East Asia Simulated by a Regional Climate Model

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Advances in Atmospheric Sciences 2008年第4期25卷 555-562页

作者：辛晓歌 Zhaoxin LI 宇如聪周天军 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Graduate University of Chinese Academy of Sciences Beijing 100049 Laboratoire de Mdteorologie Dynamique IPSL/CNRS Universite Pierre et Marie Curie Paris France National Climate Center China Meteorological Administration Beijing 100081 State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences China Meteorological Administration Beijing 100081

Responses of late spring （21 April 20 May） rainfall to the upper tropospheric cooling over East Asia are investigated with a regional climate model based on Laboratoire de M6t6orologie Dynamique Zoom （LMDZ4-RCM）. A control experiment is performed with two runs driven by the mean ERA-40 data during 1958-1977 and 1981 2000, respectively. The model reproduces the major decadal-scale circulation changes in late spring over East Asia, including a cooling in the upper troposphere and an anomalous meridional cell. Accordingly, the precipitation decrease is also captured in the southeast of the upper-level cooling region. To quantify the role of the upper-level cooling in the drought mechanism, a sensitivity experiment is further conducted with the cooling imposed in the upper troposphere. It is demonstrated that the upper-level cooling can generate the anomalous meridional cell and consequently the drought to the southeast of the cooling center. Therefore, upper tropospheric cooling should have played a dominant role in the observed late spring drought over Southeast china in recent decades.

关键词： Southeast china spring drought inter-decadal variability regional climate modeling

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Recent Progress of Earth Science Satellite Missions in china

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空间科学学报 2022年第4期42卷 712-723页

作者： SHI Jiancheng LÜDaren WANG Yu DU Yan PANG Yong YANG Dongxu WANG Xin DONG Xiaolong YANG Xiaofeng National Space Science Center Chinese Academy of SciencesBeijing 100190 Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029 Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094 South china Sea Institute of Oceanology Chinese Academy of SciencesGuangzhou 510301 Institute of Forest Resource Information Technique Chinese Academy of ForestryBeijing 100091

Earth Science from Space is an interdisciplinary discipline that studies the interactions,mechanisms,and evolution of the Earth system through space *** china,the national medium-to long-term civilian space infrastructure development plan and the space-science pilot project from the Chinese Academy of Sciences are two programs associated with advancing the Earth science from *** paper reports recent scientific findings,developments and the status of the six *** is organized as the following sections:Introduction,two satellite missions that are already in orbit—the TanSat-1 for atmospheric COand the LuTan-1 for global surface deformation,a Terrestrial Ecosystem Carbon Inventory Satellite to be launched in 2022,and three missions that passed the PhaseⅡstudy and planned for near future—the Ocean Surface Current multiscale Observation,the Terrestrial Water Resources *** and Atmospheric Components Exploring Satellites(CACES),followed by the conclusion.

关键词： Earth science from space Earth observation Energy and water cycle Carbon cycle Human activities

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Simulation of Snow Processes Beneath a Boreal Scots Pine Canopy

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Advances in Atmospheric Sciences 2008年第3期25卷 348-360页

作者：李伟平罗勇夏坤刘新 Laboratory for Climate Studies China Meteorological Administration Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100085

A physically-based multi-layer snow model Snow-Atmosphere-Soil-Transfer scheme （SAST） and a land surface model Biosphere-Atmosphere Transfer Scheme （BATS） were employed to investigate how boreal forests influence snow accumulation and ablation under the canopy. Mass balance and energetics of snow beneath a Scots pine canopy in Finland at different stages of the 2003-2004 and 2004-2005 snow seasons are analyzed. For the fairly dense Scots pine forest, drop-off of the canopy-intercepted snow contributes, in some cases, twice as much to the underlying snowpack as the direct throughfall of snow. During early winter snow melting, downward turbulent sensible and condensation heat fluxes play a dominant role together with downward net longwave radiation. In the final stage of snow ablation in middle spring, downward net all- wave radiation dominates the snow melting. Although the downward sensible heat flux is comparable to the net solar radiation during this period, evaporative cooling of the melting snow surface makes the turbulent heat flux weaker than net radiation. Sensitivities of snow processes to leaf area index （LAI） indicate that a denser canopy speeds up early winter snowmelt, but also suppresses melting later in the snow season. Higher LAI increases the interception of snowfall, therefore reduces snow accumulation under the canopy during the snow season; this effect and the enhancement of downward longwave radiation by denser foliage outweighs the increased attenuation of solar radiation, resulting in earlier snow ablation under a denser canopy. The difference in sensitivities to LAI in two snow seasons implies that the impact of canopy density on the underlying snowpack is modulated by interannual variations of climate regimes.

关键词： snow process boreal forest radiation turbulent flux sensitivity

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Dynamical Feedback between Synoptic Eddy and Low-Frequency Flow as Simulated by BCC_CSM1.1(m)

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Advances in Atmospheric Sciences 2017年第11期34卷 1316-1332页

作者： Fang ZHOU Hong-Li REN Laboratory for Climate Studies National Climate CenterChina Meteorological Administrationbeijing 100081china cma-NJU Joint Laboratory for Climate Prediction Studies School of Atmospheric SciencesNanjing Universitynanjing 210093china Department of Atmospheric Science School of Environmental StudiesChina University of Geosciencewuhan 430074china

Since the interaction between atmospheric synoptic eddy （SE）（2-8 days） activity and low-frequency （LF）（monthly） flow （referred to as SELF） plays an essential role in generating and maintaining dominant climate modes, an evaluation of the performance of BCC_CSMI.I（m） in simulating the SE feedback onto the LF flow is given in this paper. The model captures well the major spatial features of climatological eddy vorticity forcing, eddy-induced growth rate, and patterns of SELF feedback for the climate modes with large magnitudes in cold seasons and small magnitudes in warm seasons for both the Northern and Southern Hemisphere. As in observations, the eddy-induced growth rate and SELF feedback patterns in the model also show positive SE feedback. Overall, the relationships between SE and LF flow show that BCC_CSM1. l（m） satisfactorily captures the basic features of positive SE feedback, which demonstrates the simulation skill of the model for LF variability. Specifically, such an evaluation can help to find model biases of BCC_CSM1.1 （m） in simulating SE feedback, which will provide a reference for the model＇s application.

关键词： model evaluation synoptic eddy feedback simulation eddy vorticity forcing eddy-induced growth rate patternsof synoptic eddy feedback

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Comparison of the Global Energy Cycle between Chinese Reanalysis Interim and ECMWF Reanalysis

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Journal of meteorological Research 2019年第3期33卷 563-575页

作者： Bin ZHAO Bo ZHANG Chunxiang SHI Jingwei LIU Lipeng JIANG National meteorological Center China Meteorological Administration Beijing 100081 china meteorological administration Numerical Weather Prediction Center Beijing 100081 National meteorological Information Center China Meteorological Administration Beijing 100081

The global energy cycle is a diagnostic metric widely used to gauge the quality of datasets. In this paper, the "Mixed Space-Time Domain" method for diagnosis of energy cycle is evaluated by using newly developed datasets-the Chinese Reanalysis Interim (CRAI) and ECMWF Reanalysis version 5 (ERA5), over a 7-yr period (2010-16) on seasonal and monthly timescales. The results show that the energy components calculated from the two reanalysis datasets are highly consistent;however, some components in the global energy integral from CRAI are slightly larger than those from ERA5. The main discrepancy in the energy components stems from the conversion of baroclinic process, whereas the dominant difference originates from the conversion from stationary eddy available potential energy to stationary eddy kinetic energy (CES), which is caused by systematic differences in the temperature and vertical velocity in low-mid latitudes of the Northern Hemisphere and near the Antarctic, where there exist complex terrains. Furthermore, the monthly analysis reveals that the general discrepancy in the temporal variation between the two datasets also lie mainly in the CES as well as corresponding generation and dissipation rates.

关键词： global energy cycle transient waves conversion terms Chinese Reanalysis Interim (CRAI) ECMWF Reanalysis version 5 (ERA5)

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