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An Operational Precipitable Water Vapor Retrieval Algorithm for Fengyun-2F/VISSR Using a Modified Three-Band Physical Split-Window Method

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Journal of Meteorological Research 2019年第2期33卷 276-288页

作者： Juyang HU Shihao TANG Hailei LIU Min MIN key laboratory of Radiometric Calibration and Validation for Environmental Satellites National Satellite Meteorological Center China Meteorological Administration key laboratory of atmospheric sounding Chengdu University of Information Technology

The Visible and Infrared Spin-Scan Radiometer(VISSR) onboard the Fengyun-2(FY-2) satellite can provide valuable thermal infrared observations to help create a precipitable water vapor(PWV) product with high spatial and temporal resolutions. The current FY-2/VISSR PWV product in operation is produced by using a traditional two-band physical split-window(PSW) method, which produces low quality results under dry atmospheric conditions. Based on the sensitivity characteristics of FY-2 F/VISSR water vapor channel and two split-window channels to atmospheric water vapor, this study developed a new, robust operational PWV retrieval algorithm for FY-2 F to improve the operational precision of the current PWV product. The algorithm uses a modified three-band PSW method, which adds a scale for the water vapor channel in the improved three-band PSW method. Integrated PWV products from the radiosonde data in 2016 are used here to validate the precision of the PWV retrieved by the modified three-band and traditional two-band PSW methods. The mean bias, root mean square error(RMSE), and correlation coefficient of the PWV retrieved by the modified three-band PSW method are 0.28 mm, 4.53 mm, and 0.969, respectively. The accuracy is much better than the PWV retrieved by the two-band method, whose mean bias, RMSE, and correlation coefficient are 12.67 mm, 29.35 mm, and 0.23. Especially, in mid-or high-latitude regions, the RMSE of the PWV is improved from 10 to 2 mm by changing the inversion in the two-band method to the modified three-band PSW method. Furthermore, the modified three-band PSW results show a better consistency with the radiosonde PWV at any zonal belt and season than the two-band PSW results. This new algorithm could significantly improve the quality of the current FY-2 F/VISSR PWV product, especially at sites where the actual PWV are lower than 15 mm.

关键词： physical split-window (PSW) method precipitable water vapor (PWV) FY-2F/VISSR thermal infrared

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A microphysical investigation of different convective cells during the precipitation event with sustained high-resolution observations

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Frontiers of Earth Science 2024年第2期18卷 279-295页

作者： Ziheng HUANG Zheng RUAN Debin SU State key laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China College of Electronic Engineering Chengdu University of Information TechnologyChengdu 610225China key laboratory of atmospheric sounding China Meteorological AdministrationChengdu 610225China

The growth and breakup processes of raindrops within a cloud influence the rain intensity and the sizes of raindrops on the *** Doppler velocity spectrum acquired by a vertically pointing radar(VPR)contains information on atmospheric turbulence and the size classification of falling *** this study,the four types of Convective Cells(CC)during precipitation events with more than 700 mm of precipitation in southern China are *** characteristics of four types of CCs correspond to the isolated convection,the early stage,the mature stage,and the decline stage of organizational convection,in that *** analysis using retrieval of vertical air motion(Vair)and raindrop evolution in clouds from Doppler velocity spectra collected by C-band VPR revealed the growth and breakup of falling raindrops with dynamic *** raindrops appear in the early stages and are accompanied by ice particles,which are impacted by the falling path᾽s *** aggregation,which is primarily related to the alternation of updraft and downdraft,accounts for the mature stage᾽s high efficiency of surface *** CCs in the decline stage originate from the shallow uplift in the weak and broad downdraft under conditions of enough water *** updraft dominates the stage of isolated *** of convective cells could be more accurately represented in model evaluations.

关键词： cloud microphysics convective systems convective cell vertically pointing radar observations Doppler velocity spectrum

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Modeling study on seasonal variation in aerosol extinction properties over China

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Journal of Environmental Sciences 2014年第1期26卷 97-109页

作者： Yi Gao Meigen Zhang State key laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences

To investigate the seasonal variation of aerosol optical depth （AOD）, extinction coefficient （EXT）, single scattering albedo （SSA） and the decomposed impacts from sulfate （SO42-） and black carbon （BC） over China, numerical experiments are conducted from November 2007 to December 2008 by using WRF-Chem. Comparison of model results with measurements shows that model can reproduce the spatial distribution and seasonal variation of AOD and SSA. Over south China, AOD is largest in spring （0.6-1.2） and lowest in summer （0.2-0.6）. Over north, northeast and east China, AOD is highest in summer while lowest in winter. The high value of EXT under 850 hPa which is the reflection of low visibility ranges from 0.4-0.8 km-1 and the high value area shifts to north during winter, spring and summer, then back to south in autumn. SSA is 0.92-0.94 in winter and 0.94-0.96 for the other three seasons because of highest BC concentration in winter over south China. Over east China, SSA is highest （0.92-0.96） in summer, and 0.88-0.92 during winter, spring and autumn as the concentration of scattering aerosol is highest while BC concentration is lowest in summer over this region. Over north China, SSA is highest （0.9-0.94） in summer and lowest （0.82-0.86） in winter due to the significant variation of aerosol concentration. The SOn2- induced EXT increases about 5%- 55% and the impacts of BC on EXT is much smaller （2%-10%）. The SO42--induced increase in SSA is 0.01-0.08 and the BC-induced SSA decreases 0.02-0.18.

关键词： seasonal variation AOD EXT SSA China WRF-Chem

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Synergistic impacts of anthropogenic and biogenic emissions on summer surface O_3 in East Asia

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Journal of Environmental Sciences 2013年第3期25卷 520-530页

作者： Yu Qu Junling An Jian Li State key laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences

A factor separation technique and an improved regional air quality model （RAQM） were applied to calculate synergistic contributions of anthropogenic volatile organic compounds （AVOCs）,biogenic volatile organic compounds （BVOCs） and nitrogen oxides （NOx） to daily maximum surface O3（O3DM） concentrations in East Asia in summer （June to August 2000）.The summer averaged synergistic impacts of AVOCs and NOx are dominant in most areas of North China,with a maximum of 60 ppbv,while those of BVOCs and NOx are notable only in some limited areas with high BVOC emissions in South China,with a maximum of 25 *** result implies that BVOCs contribute much less to summer averaged O3DM concentrations than AVOCs in most areas of East Asia at a coarse spatial resolution （1×1） although global emissions of BVOCs are much greater than those of *** maximum total contributions of BVOCs can approach 20 ppbv in North China,but they can reach 40 ppbv in South China,approaching or exceeding those in some developed countries in Europe and North *** emissions in such special areas should be considered when O3 control measures are *** contributions among AVOCs,BVOCs and NOx significantly enhance O3 concentrations in the Beijing-Tianjin-Tangshan region and decrease them in some areas in South ***,the total contributions of BVOCs to O3DM vary significantly from day to day and from location to *** result suggests that O3 control measures obtained from episodic studies could be limited for long-term applications.

关键词： regional air quality model volatile organic compounds O3 factor separation technique synergistic contribution

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Estimation of carbon dioxide flux and source partitioning over Beijing, China

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Journal of Environmental Sciences 2013年第12期25卷 2429-2434页

作者： Tao Song Yuesi Wang Yang Sun State key laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences

The magnitude and partitioning of carbon dioxide emission from the urban area in Beijing, China was estimated based on a statistical approach. Results showed that the urban surface is a net source of CO2 to atmosphere. The main sources of CO2 are vehicles, which accounted for 75.5% and 38.9% of CO2 emission in summer and winter, respectively. At midday in summer, the CO2 uptake of-0.034 mg/（m^***） indicated that vegetation is an important sink of CO2 in summer. Comparison between the annual emission rates of CO2 from the statistical approach and that directly measured by the eddy covariance technique implies that a bottom-up emission approach is a viable means to estimate CO2 emission in an urban area.

关键词： C02 emission source eddy covariance

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Evaluating the Algorithm for Correction of the Bright Band Effects in QPEs with S-, C-and X-Band Dual-Polarized Radars

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Advances in atmospheric Sciences 2019年第1期36卷 41-54页

作者： Yang CAO Debin SU Xingang FAN Hongbin CHEN key laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of Sciences College of Electronic Engineering Chengdu University of Information Technology Sichuan Meteorological Disasters Prevention Technology Center China Meteorological Administration key laboratory of atmospheric sounding Department of Geography and Geology Western Kentucky University

The bright band, a layer of enhanced radar reflectivity associated with melting ice particles, is a major source of signifi- cant overestimation in quantitative precipitation estimation （QPE） based on the Z-R （reflectivity factor-rain rate） relationship. The effects of the bright band on radar-based QPE can be eliminated by vertical profile of reflectivity （VPR） correction. In this study, we applied bright-band correction algorithms to evaluate three different bands （S-, C- and X-band） of dual-polarized radars and to reduce overestimation errors in Z-R relationship-based QPEs. After the reflectivity was corrected by the algo- rithms using average VPR （AVPR） alone and a combination of average VPR and the vertical profile of the copolar correlation coefficient （AVPR＋CC）, the QPEs were derived. The bright-band correction and resulting QPEs were evaluated in eight precipitation events by comparing to the uncorrected reflectivity and rain-gange observations, separately. The overestimation of Z-R relationship-based QPEs associated with the bright band was reduced after correction by the two schemes for which hourly rainfall was less than 5 mm. For the verification metrics of RMSE （root-mean-square error）, RMAE （relative mean absolute error） and RMB （relative mean bias） of QPEs, averaged over all eight cases, the AVPR method improved from 2.28, 0.94 and 0.78 to 1.55, 0.60 and 0.40, respectively, while the AVPR＋CC method improved to 1.44, 0.55 and 0.30, respectively. The QPEs after AVPR＋CC correction had less overestimation than those after AVPR correction, and similar conclusions were drawn for all three different bands of dual-polarized radars.

关键词： dual-polarized radar bright band QPE vertical profile of reflectivity

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Mass and isotopic concentrations of water-insoluble refractory carbon in total suspended particulates at *** Observatory(China)

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Particuology 2015年第3期13卷 24-31页

作者： Xiangdong Zheng Chengde Shen Guojiang Wan Jie Tang Kexin Liu key laboratory of atmospheric Chemistry Chinese Academy of Meteorological Sciences State key laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of GeochemistryChinese Academy of Sciences State key laboratory of Environment Geochemistry Institute of GeochemistryChinese Academy of Sciences Center of Meteorological sounding Chinese Meteorological Administration State key laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics Peking University

Mass concentration and isotopic values δ13C and 14C are presented for the water-insoluble refractory carbon （WIRC） component of total suspended particulates （TSP）, collected weekly during 2003, as well as from October 2005 to May 2006 at the WMO-GAW Mt. Waliguan （WLG） site. The overall average WlRC mass concentration was （1183 ± 120）ng/m3 （n = 79）, while seasonal averages were 2081 ± 1707 （spring）, 454±205 （summer）, 650 ±411 （autumn）, and 1019 ± 703 （winter） ng/m3. Seasonal variations in WIRC mass concentrations were consistent with black carbon measurements from an aethalometer, although WIRC concentrations were typically higher, especially in winter and spring. The δ13C PDB value （-25.3 ± 0.8）%0 determined for WIRC suggests that its sources are C3 biomass or fossil fuel combustion. No seasonal change in δ13C PDB was evident. The average percent Modern Carbon （pMC） for 14C in WIRC for winter and spring was （67.2 ± 7.7）% （n = 29）. Lower pMC values were associated with air masses trans- ported from the area east of WLG, while higher pMC values were associated with air masses from the Tibetan Plateau, southwest of WLG. Elevated pMC values with abnormally high mass concentrations of TSP and WIRC were measured during a dust storm event.

关键词： Water-insoluble refractory carbon (WIRC)Mass concentration813C14CMt. Waliguan (WLG)

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Measurement errors and correction of the UAT-2 ultrasonic anemometer

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Science China(Technological Sciences) 2015年第4期58卷 677-686页

作者： CHENG Xue Ling PENG Zhen HU Fei ZENG Qing Cun LUO Wei Dong ZHAO Yi Jun HONG Zhong Xiang State key laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences Department of atmospheric Science Nanjing University

Two kinds of measurement errors have been observed in the recently developed UAT-2 ultrasonic *** is the flow distortion produced by a"blocking effect",and the other is the angle of attack caused by the vertical misalignment of the ***,we study these errors and discuss the possible correction *** a wind tunnel experiment and numerical simulation,a 3D calibration matrix was developed to correct the"blocking effect".In the field test,the angle of attack was detected by an inclinometer settled on the reference plane of the anemometer,and the instrumental misalignment or tilt was corrected by a coordinate *** combined use of an inclinometer and the proposed correction method may help find a new approach for vertical velocity correction.

关键词： ultrasonic anemometer transducer array blocking effect attack angle inclinometer

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On the Evolution and Structure of a Radiation Fog Event in Nanjing

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Advances in atmospheric Sciences 2011年第1期28卷 223-237页

作者：刘端阳杨军牛生杰李子华 key laboratory for atmospheric Physics and atmospheric Environment Nanjing University of Information Science & Technology

An extremely dense radiation fog event during 10-11 December 2007 was studied to understand its macro-micro-physics in relation to dynamic and thermodynamic structures of the boundary layer, as well as its structural evolution in conjunction with the air-surface exchange of heat and water vapor. The findings are as follows. The extreme radiation fog process was divisible into formation, development, mature, and dissipation phases, depending on microstructure and visibility. This fog event was marked by rapid evolution that occurred after sunrise, when enhanced surface evaporation and cold air intrusion led to a three order of magnitude increase in liquid water content （LWC） in just 20 minutes. The maximum droplet diameter （MDD） increased four-fold during the same period. The fog structure was two-layered, with the top of both the surface-layer and upper-layer components characterized by strong temperature and humidity inversions, and low-level jets existed in the boundary layer above each fog layer. Turbulence intensity, turbulent kinetic energy, and friction velocity differed remarkably from phase to phase： these features increased gradually before the fog formation and decreased during the development phase; during the mature and dissipation phases these characteristics increased and then decreased again. In the development and mature stages, the mean kinetic energy of the lower-level winds decreased pronouncedly, both in the horizontal and vertical directions.

关键词： Nanjing dense fog dynamic and thermodynamic structures intrusion turbulence

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Modeling nitrate aerosol distributions and its direct radiative forcing in East Asia with RAMS-CMAQ

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Particuology 2013年第3期11卷 256-263页

作者： Xiao Han Meigen Zhang Baorong Zhou State key laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences Xinghua Meteorological Bureau

The geographical and seasonal characteristics in nitrate aerosol and its direct radiative forcing over East Asia are analyzed by using the air quality modeling system RAMS-CMAQ coupled with an aerosol optical properties/radiative transfer module. For evaluating the model performance, nitrate ion concentration in precipitation, and mixing ratios of PMl0, and some gas precursors of aerosol during the whole year of 2007 are compared against surface observations at 17 stations located in Japan, Korea, and China, and the satellite retrieved NO2 columns, The comparison shows that the simulated values are generally in good agreement with the observed ones. Simulated monthly averaged values are mostly within a factor of 2 of the measurements at the observation stations. The distribution patterns of NO2 from simulation and satellite measurement are also similar with each other. Analysis of the distribution features of monthly and yearly averaged mass concentration and direct radiative forcing （DRF） of nitrate indicates that the nitrate aerosol could reach about 25-30% of the total aerosol mass concentration and DRF in Sichuan Basin, Southeast China, and East China where the high mass burden of all major aerosols concentrated. The highest mass concentration and strongest DRF of nitrate could exceed 40 μg/m^3 and -5 Wire2, respectively. It also indicates that other aerosol species, such as carbonaceous and mineral particles, could obviously influence the nitrate DRF for they are often internally mixed with each other.

关键词： Nitrate aerosolDirect radiative forcing CMAQEAN ET AOD

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