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Evaluation of meteorological predictions by the WRF model at Barrow, Alaska and Summit, Greenland in the Arctic in April 2019

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Advances in Polar Science 2023年第4期34卷 352-367页

作者： ZHANG Tong CAO Le LI Simeng WANG Jiandong China Meteorological Administration aerosol-cloud-Precipitation Key laboratory Nanjing University of Information Science&TechnologyNanjing 210044China

Accurate meteorological predictions in the Arctic are important in response to the rapid climate change and insufficient meteorological observations in the Arctic.In this study,we adopted a high-resolution Weather research and Forecasting(WRF)model to simulate the meteorology at two Arctic stations(Barrow and Summit)in April 2019.Simulation results were also evaluated by using surface measurements and statistical parameters.In addition,weather charts during the studied time period were also used to assess the model performance.The results demonstrate that the WRF model is able to accurately capture the meteorological parameters for the two Arctic stations and the weather systems such as cyclones and anticyclones in the Arctic.Moreover,we found the model performance in predicting the surface pressure the best while the performance in predicting the wind the worst among these meteorological predictions.However,the wind predictions at these Arctic stations were found to be more accurate than those at urban stations in mid-latitude regions,due to the differences in land features and anthropogentic heat sources between these regions.In addition,a comparison of the simulation results showed that the prediction of meteorological conditions at Summit is superior to that at Barrow.Possible reasons for the deviations in temperature predictions between these two Arctic stations are uncertainties in the treatments of the sea ice and the cloud in the model.With respect to the wind,the deviations may source from the overestimation of the wind over the sea and at coastal stations.

关键词： Arctic WRF meteorological parameters synoptic patterns model assessment

Roles of SO_2 oxidation in new particle formation events

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Journal of Environmental Sciences 2015年第4期27卷 90-101页

作者： He Meng Yujiao Zhu Greg J.Evans Cheol-Heon Jeong Xiaohong Yao Key lab of Marine Environmental Science and Ecology Ministry of Education Ocean University of China Southern Ontario Centre for Atmospheric aerosol research University of Toronto

The oxidation of SO2 is commonly regarded as a major driver for new particle formation（NPF） in the atmosphere. In this study, we explored the connection between measured mixing ratio of SO2 and observed long-term（duration 〉 3 hr） and short-term（duration〈 1.5 hr） NPF events at a semi-urban site in Toronto. Apparent NPF rates（J30） showed a moderate correlation with the concentration of sulfuric acid（[H2SO4]） calculated from the measured mixing ratio of SO2 in long-term NPF events and some short-term NPF events（Category I）（R^2= 0.66）. The exponent in the fitting line of J30~ [H2SO4]nin these events was1.6. It was also found that SO2 mixing ratios varied a lot during long-term NPF events,leading to a significant variation of new particle counts. In the SO2-unexplained short-term NPF events（Category II）, analysis showed that new particles were formed aloft and then mixed down to the ground level. Further calculation results showed that sulfuric acid oxidized from SO2 probably made a negligible contribution to the growth of 〉 10 nm new particles.

关键词： Nucleation Particle growth Sulfuric acid Photochemical oxidation SO2

One-Dimensional Variational Retrieval of Temperature and Humidity Profiles from the FY4A GIIRS

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Advances in Atmospheric Sciences 2022年第3期39卷 471-486页

作者： Qiumeng XUE Li GUAN Xiaoning SHI Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological AdministrationNanjing University of Information Science and TechnologyNanjing 210044China Department of Mathematics University of Wisconsin-MadisonMadison 53706USA

A physical retrieval approach based on the one-dimensional variational(1 D-Var) algorithm is applied in this paper to simultaneously retrieve atmospheric temperature and humidity profiles under both clear-sky and partly cloudy conditions from FY-4 A GIIRS(geostationary interferometric infrared sounder) observations. Radiosonde observations from upper-air stations in China and level-2 operational products from the Chinese National Satellite Meteorological Center(NSMC)during the periods from December 2019 to January 2020(winter) and from July 2020 to August 2020(summer) are used to validate the accuracies of the retrieved temperature and humidity profiles. Comparing the 1 D-Var-retrieved profiles to radiosonde data, the accuracy of the temperature retrievals at each vertical level of the troposphere is characterized by a root mean square error(RMSE) within 2 K, except for at the bottom level of the atmosphere under clear conditions. The RMSE increases slightly for the higher atmospheric layers, owing to the lack of temperature sounding channels there.Under partly cloudy conditions, the temperature at each vertical level can be obtained, while the level-2 operational products obtain values only at altitudes above the cloud top. In addition, the accuracy of the retrieved temperature profiles is greatly improved compared with the accuracies of the operational products. For the humidity retrievals, the mean RMSEs in the troposphere in winter and summer are both within 2 g kg^(–1). Moreover, the retrievals performed better compared with the ERA5 reanalysis data between 800 h Pa and 300 h Pa both in summer and winter in terms of RMSE.

关键词： temperature and humidity profiles one-dimensional variational(1D-Var) GIIRS hyperspectral data

Variability of Raindrop Size Distribution during a Regional Freezing Rain Event in the Jianghan Plain of Central China

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Advances in Atmospheric Sciences 2023年第4期40卷 725-742,I0015-I0018页

作者： Jingjing LÜ Yue ZHOU Zhikang FU Chunsong LU Qin HUANG Jing SUN Yue ZHAO Shengjie NIU Key laboratory for aerosol-cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science&TechnologyNanjing 210044China Hubei Key laboratory for Heavy Rain Monitoring and Warning research Institute of Heavy RainChina Meteorological AdministrationWuhan 430205China Department of Physics University of AucklandAuckland 1010New Zealand

The characteristics of the raindrop size distribution(DSD)during regional freezing rain(FR)events that occur throughout the phase change(from liquid to solid)are poorly understood due to limited observations.We investigate the evolution of microphysical parameters and the key formation mechanisms of regional FR using the DSDs from five disdrometer sites in January 2018 in the Jianghan Plain(JHP)of Central China.FR is identified via the size and velocity distribution measured from a disdrometer,the discrete Fréchet distancemethod,surface temperature,human observations,and sounding data.With the persistence of precipitation,the emergence of graupel or snowflakes significantly reduces the proportion of FR.The enhancement of this regional FR event is mainly dominated by the increase in the number concentration of raindrops but weakly affected by the diameters.To improve the accuracy of quantitative precipitation estimation for the FR event,a modified second-degree polynomial relation between the shapeμand slopeΛof gamma DSDs is derived,and a new Z-R(radar reflectivity to rain rate)relationship is developed.The mean values of mass-weighted mean diameters(D_(m))and generalized intercepts(lgN_(w))in FR are close to the stratiform results in the northern region of China.Both the melting of tiny-rimed graupels and large-dry snowflakes are a response to the formation of this regional FR process in the JHP,dominated by the joint influence of the physical mechanism of warm rain,vapor deposition,and aggregation/riming coupled with the effect of weak convective motion in some periods.

关键词： freezing rain raindrop size distribution hydrometeor type classification microphysical characteristics lgNw-Dm distribution Jianghan Plain

MICROSTRUCTURES AND TEMPORAL VARIATION CHARACTERISTICS DURING A SEA FOG EVENT ALONG THE WEST COAST OF THE TAIWAN STRAIT

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Journal of Tropical Meteorology 2017年第2期23卷 155-165页

作者：张悦樊曙先张舒婷魏锦成 Key laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and Technology Chongqing Institute of Meteorological Sciences Key laboratory for aerosol-cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science and Technology Key laboratory for aerosol-cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science and Technology Meteorological Bureau of Xiamen

Synoptic systems and microphysical properties associated with a sea fog event are analyzed based on the measurements of visibility, meteorological elements and fog droplet spectrum from a comprehensive field campaign in Xiamen, Fujian province during spring 2013. The influences of meteorological elements on the microstructures of the sea fog are also discussed. The results showed that the wind speed and direction changed suddenly during the intermittent and disperse phases of the sea fog. Liquid water content, number concentration and average diameter varied obviously in the development, mature and disperse phases of the sea fog. The burst re-enforcement of sea fog was accompanied by explosive broadening of fog droplet spectrum; average diameter, number concentration and liquid water content increased sharply; and background meteorological conditions also changed significantly. The microstructures fluctuated intensely due to changes in turbulence, radiation and meteorological conditions at different stages, including nucleation, condensation, coagulation, and evaporation, as well as the discontinuity of spatial distribution of droplets.

关键词： atmospheric physics sea fog meteorological elements microstructure temporal variation

Temporal and Spatial Distribution Characteristics of Lightning Activity over the Pacific Ocean and Adjacent Land and Its Relationship with AOD and CAPE

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Journal of Tropical Meteorology 2022年第4期28卷 473-488页

作者：初雨郭凤霞张志伟邹迪可吴泽怡刘舟鲁鲜 Key laboratory of Meteorological Disaster Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological AdministrationNanjing University of Information Science and TechnologyNanjing 210044 China

Based on LIS/OTD gridded lightning climatology data,ERA5 reanalysis data,and MODIS atmosphere monthly global products,we examined latitudinal and daily variations of lightning activity over land,offshore areas,open sea,and all marine areas(i.e.,the aggregate of open sea and offshore areas)for different seasons over the Pacific Ocean and the adjacent land areas at 65°N-50°S,99°E-78°W,and analysed the relationships of lightning activity with CAPE(Convective Available Potential Energy)and AOD(aerosol Optical Depth).At any given latitude,the lightning density is the highest over land,followed by offshore areas,all marine areas and the open sea in sequence.The lightning density over land is approximately an order of magnitude greater than that over all marine areas.Lightning activity over land,offshore areas,open sea,and all marine areas varies with season.The diurnal variation of lightning density over land has a single-peak pattern.Over the offshore area,open sea,and all marine areas,lightning densities have two maxima per day.The magnitude of the daily variation in mean lightning density is the largest over land and the smallest over the open sea.The lightning density over the Pacific Ocean and adjacent land areas is significantly and positively correlated with CAPE.The correlation is the strongest over land and the weakest over the open sea.cloud Base Height(CBH)may affect the efficiency of CAPE conversion to updraft.CAPE has a positive effect on lightning activity and has a greater impact on land than on the ocean.Over the sea,both CAPE and AOD can contribute to lightning activity,but the magnitudes of the influence of CAPE and AOD on lightning activity remain to be determined.Lightning activity over land and sea is a result of the combined action of AOD and CAPE.

关键词： Pacific lightning land-sea contrast thermal conditions aerosol

Source analysis of spaceborne microwave radiometer interference over land

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Frontiers of Earth Science 2016年第1期10卷 135-144页

作者： Li GUAN Sibo ZHANG Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science & Technology Nanjing 210044 China

Satellite microwave thermal emissions mixed with signals from active sensors are referred to as radio- frequency interference （RFI）. Based on Advanced Micro- wave Scanning Radiometer-Earth Observing System （AMSR-E） observations from June 1 to 16, 2011, RFI over Europe was identified and analyzed using the modified principal component analysis algorithm in this paper. The X band AMSR-E measurements in England and Italy are mostly affected by the stable, persistent, active microwave transmitters on the surface, while the RFI source of other European countries is the interference of the reflected geostationary TV satellite downlink signals to the measurements of spacebome microwave radiometers. The locations and intensities of the RFI induced by the geostationary TV and communication satellites changed with time within the observed period. The observations of spacebome microwave radiometers in ascending portions of orbits are usually interfered with over European land, while no RFI was detected in descending passes. The RFI locations and intensities from the reflection of downlink radiation are highly dependent upon the relative geometry between the geostationary satellite and the measuring passive sensor. Only these fields of view of a spaceborne instrument whose scan azimuths are close to the azimuth relative to the geostationary satellite are likely to be affected by RFI.

关键词： AMSR-E RFI geostationary TV satellite

Mixing state of individual carbonaceous particles during a severe haze episode in January 2013,Nanjing,China

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Particuology 2015年第3期13卷 16-23页

作者： Honglei Wang Bin Zhu Zefeng Zhang Junlin An Lijuan Shen Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological AdministrationNanjing University of Information Science and Technology Jiaxing Environmental Monitoring Station

Chemical composition, hourly counts, and sizes of atmospheric carbonaceous particles were measured to investigate their mixing state on clear and hazy days. 823,122 carbonaceous particles with sizes 0.2-2.0μm was analyzed using a single-particle aerosol mass spectrometer from 1st to 17th January 2013. Particle types included biomass/biofuel burning particles （biomass）, element carbon （EC-dominant） particles that were also mixed with biomass/biofuel burning species （EC-biomass） or secondary species （EC-secondary）, organic carbon （OC）, internally mixed OC and EC （OCEC）, ammonium-containing （ammo- nium） and sodium-containing （sodium） particles. On clear days the top ranked carbonaceous particle types were biomass （48.2%）, EC-biomass （15.7%）, OCEC （11.1%）, and sodium （9.6%）, while on hazy days they were biomass （37.3%）, EC-biomass （17,6%）, EC-secondary （16.6%）, and sodium （12.7%）. The fractions of EC-secondary, ammonium （10%）, and sodium particle types were elevated on hazy days. Numbers of EC-secondary particles were more than four times those on clear days （4.1%）. Thus, carbonaceous particles mixed with ammonium, nitrate and sulfate during aging and transport, enhancing their light extinction effects and hygroscopic growth under high relative humidity on hazy days, further reducing visibility. Our real-time single-particle data showed that changes to mixing state had a significant impact on light extinction during haze events in Nanjing.

关键词： HazeSingle particleMixing stateSPAMSCarbonaceous particleSecondary aerosols

Effect of Initial Vortex Intensity Correction on Tropical Cyclone Intensity Prediction:A Study Based on GRAPES_TYM

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Journal of Meteorological research 2020年第2期34卷 387-399页

作者： Liwen WANG Suhong MA Key laboratory for aerosol–cloud–Precipitation of China Meteorological Administration School of Atmospheric PhysicsNanjing University of Information Science&TechnologyNanjing 210044 National Meteorological Center China Meteorological AdministrationBeijing 100081

Predicting the intensity of tropical cyclones(TCs)is challenging in operational weather prediction systems,partly due to the difficulty in defining the initial vortex.In an attempt to solve this problem,this study investigated the effect of initial vortex intensity correction on the prediction of the intensity of TCs by the operational numerical prediction system GRAPES_TYM(Global and Regional Assimilation and Prediction System_Typhoon Model)of the National Meteorological Center of the China Meteorological Administration.The statistical results based on experiments using data for major TCs in 2018 show that initial vortex intensity correction can reduce the errors in mean intensity for up to 120-h integration,with a noticeable decrease in the negative bias of intensity and a slight increase in the mean track error.The correction leads to an increase in the correlation coefficient of Vmax(maximum wind speed at 10-m height)for the severe typhoon and super typhoon stages.Analyses of the errors in intensity at different stages of intensity(including tropical storms,severe tropical storms,typhoons,severe typhoons,and super typhoons)show that vortex intensity correction has a remarkable positive influence on the prediction of super typhoons from 0 to 120h.Analyses of the errors in intensity for TCs with different initial intensities indicate that initial vortex correction can significantly improve the prediction of intensity from 24 to 96 h for weak TCs(including tropical storms and severe tropical storms at the initial time)and up to 24 h for strong TCs(including severe typhoons and super typhoons at the initial time).The effect of the initial vortex intensity correction is more important for developing TCs than for weakening TCs.

关键词： vortex intensity correction intensity bias intensity error tropical cyclones