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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 *** 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 *** is identified via the size and velocity distribution measured from a disdrometer,the discrete Fréchet distancemethod,surface temperature,human observations,and sounding *** the persistence of precipitation,the emergence of graupel or snowflakes significantly reduces the proportion of *** enhancement of this regional FR event is mainly dominated by the increase in the number concentration of raindrops but weakly affected by the *** 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 *** 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 *** 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

A New Algorithm of rain Type Classification for GPM Dual-Frequency Precipitation Radar in Summer Tibetan Plateau

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Advances in Atmospheric Sciences 2024年第11期41卷 2093-2111页

作者： Yunfei FU Liu YANG Zhenhao WU Peng ZHANG Songyan GU Lin CHEN Sun NAN School of Earth and Space Sciences CMA-USTC Laboratory of Fengyun Remote SensingUniversity of Science and Technology of ChinaHefei 230026China Hubei Key Laboratory for heavy rain Monitoring and Warning Research Institute of Heavy RainChina Meteorological AdministrationWuhan 430205China National Satellite Meteorological Center China Meteorological AdministrationBeijing 100081China

In this study, a new rain type classification algorithm for the Dual-Frequency Precipitation Radar(DPR) suitable over the Tibetan Plateau(TP) was proposed by analyzing Global Precipitation Measurement(GPM) DPR Level-2 data in summer from 2014 to 2020. It was found that the DPR rain type classification algorithm(simply called DPR algorithm) has mis-identification problems in two aspects in summer TP. In the new algorithm of rain type classification in summer TP,four rain types are classified by using new thresholds, such as the maximum reflectivity factor, the difference between the maximum reflectivity factor and the background maximum reflectivity factor, and the echo top height. In the threshold of the maximum reflectivity factors, 30 d BZ and 18 d BZ are both thresholds to separate strong convective precipitation, weak convective precipitation and weak precipitation. The results illustrate obvious differences of radar reflectivity factor and vertical velocity among the three rain types in summer TP, such as the reflectivity factor of most strong convective precipitation distributes from 15 d BZ to near 35 d BZ from 4 km to 13 km, and increases almost linearly with the decrease in height. For most weak convective precipitation, the reflectivity factor distributes from 15 d BZ to 28 d BZ with the height from 4 km to 9 km. For weak precipitation, the reflectivity factor mainly distributes in range of 15–25 d BZ with height within 4–10 km. It is also shows that weak precipitation is the dominant rain type in summer TP, accounting for 40%–80%,followed by weak convective precipitation(25%–40%), and strong convective precipitation has the least proportion(less than 30%).

关键词： satellite precipitation radar rain type classification method Tibetan Plateau strong convective precipitation

Integrative Monsoon Frontal rainfall Experiment(IMFRE-I):A Mid-Term Review

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Advances in Atmospheric Sciences 2021年第3期38卷 357-374页

作者： Chunguang CUI Xiquan DONG Bin WANG Baike XI Yi DENG Yihui DING Hubei Key Laboratory for heavy rain Monitoring and Warning Research Institute of Heavy RainChina Meteorological AdministrationWuhan 430205China Department of Hydrology and Atmospheric Sciences University of ArizonaTucsonArizona 85721-0011USA School of Earth and Atmospheric Sciences Georgia Institute of TechnologyAtlantaGeorgia 30332-0340USA National Climate Center China Meteorological AdministrationBeijing 100081China

The mei-yu season,typically occurring from mid-June to mid-July,on average,contributes to 32%of the annual precipitation over the Yangtze-Huai River Valley(YHRV)and represents one of the three heavy-rainfall periods in ***,we briefly review the large-scale background,synoptic pattern,moisture transport,and cloud and precipitation characteristics of the mei-yu frontal systems in the context of the ongoing Integrative Monsoon Frontal rainfall Experiment(IMFRE)field *** one of the campaign,IMFRE-I,was conducted from 10 June to 10 July 2018 in the middle reaches of the *** by the Wuhan institute of heavy rain(IHR)with primary support from the National Natural Science Foundation of China,IMFRE-I maximizes the use of our observational capacity enabled by a suite of ground-based and remote sensing instruments,most notably the IHR Mesoscale heavy rainfall Observing System(MHROS),including different wavelengths of radars,microwave radiometers,and *** KA350(Shanxi King-Air)aircraft participating in the campaign is equipped with Ka-band cloud radar and different *** comprehensive datasets from both the MHROS and aircraft instruments are combined with available satellite observations and model simulations to answer the three scientific questions of *** highlights from a previously published special issue are included in this review,and we also briefly introduce the IMFRE-II field campaign,conducted during June-July 2020,where the focus was on the spatiotemporal evolutions of the mei-yu frontal systems over the middle and lower reaches of the YHRV.

关键词： mei-yu frontal system IMFRE-I IMFRE-II

A new sequential data assimilation method

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Science China(Technological Sciences) 2009年第4期52卷 1027-1038页

作者： HAN YueQi ZHANG YaoCun WANG YunFeng YE Song FANG HanXian Department of Atmospheric Sciences Nanjing UniversityNanjing 210093China institute of Meteorology PLA University of Science and TechnologyNanjing 211101China institute of heavy rain China Meteorological AdministrationWuhan 430074China

A new sequential data assimilation method named "Monte Carlo H ∞ filter" is introduced based on H ∞ filter technique and Monte Carlo method in this paper. This method applies to nonlinear systems in condition of lacking the statistical properties of observational errors. In order to compare the as- similation capability of Monte Carlo H ∞ filter with that of the ensemble Kalman filter (EnKF) in solving practical problems caused by temporal correlation or spatial correlation of observational errors, two numerical experiments are performed by using Lorenz (1963) system and shallow-water equations re- spectively. The result is that the assimilation capability of the new method is better than that of EnKF method. It is also shown that Monte Carlo H ∞ filter assimilation method is effective and suitable to nonlinear systems in that it does not depend on the statistical properties of observational errors and has better robustness than EnKF method when the statistical properties of observational errors are varying. In addition, for the new method, the smallest level factor founded by search method is flow-dependent.

关键词： sequential data assimilation Monte Carlo H∞ filter correlation of observational errors robustness flow-dependent

An Interdecadal Change of Summer Atmospheric Circulation over Asian Mid-High Latitudes and Associated Effects

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Journal of Tropical Meteorology 2020年第3期26卷 363-376页

作者： ZHOU Chang-yan LI Di REN Qian QI Dong-mei institute of Plateau Meteorology China Meteorological Administration/Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan ProvinceChengdu 610072 China

The atmospheric circulation over the mid-high latitudes in Asia has an important influence on regional climate,yet its long-term variation has not been fully *** main task of this study is to reveal the interdecadal variation features of summer atmospheric circulation over Asian mid-high latitudes in recent *** results show that the atmospheric circulation over mid-high latitudes of Asia has stronger interdecadal fluctuations than that over low latitudes and one significant change center appears near Lake *** is found that the atmospheric circulation near Lake Baikal has a significant interdecadal change around 1996 and a deep anomalous anticyclonic circulation has been controlling this region since then,which contributes to the significant increase in the surface temperature near Lake Baikal since 1997 and makes the region a remarkable warming center in Asia in recent 40 *** 1997-2015,the pattern of less precipitation in the north and more precipitation in the south of east China is closely related to the anomalous anticyclonic circulation near Lake ***,this anomalous circulation near Lake Baikal has been found to contribute to the obvious interdecadal decrease of the precipitation in northeast China and north China *** sea surface temperature(SST)of northwestern Atlantic is an important influence factor to the interdecadal change in the atmospheric circulation near Lake Baikal around 1996.

关键词： Asian mid-high latitudes interdecadal change effect Atlantic SST

Impacts of Climate Change on Cotton Yield in China from 1961 to2010 Based on Provincial Data

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Journal of Meteorological Research 2015年第3期29卷 515-524页

作者：陈超庞艳梅潘学标张立祯 institute of Plateau Meteorology China Meteorological Administration heavy rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province College of Resources and Environment China Agricultural University

To develop scientific countermeasures, the impacts of climate change on cotton yield during 1961-2010 in three major cotton-producing regions of China were studied by using the available provincial data. The results indicate that （1） a rise in average temperature increased the cotton yield in most provinces of Northwest China and the Yellow River valley; however, the rise in average temperature decreased the cotton yield in the Yangtze River valley. Moreover, cotton production across the entire study region was reduced by approximately 0.1% relative to the average during 1961-2010. （2） A decrease in diurnal temperature range （DTR） reduced cotton yield in some provinces, while a beneficial DTR effect was observed in the other provinces. Changes in DTR resulted in an average decrease in production by approximatly 5.5% across the entire study region. （3） A change in the amount of precipitation increased the cotton yield in some provinces; however, it caused a decrease in other provinces. The decrease in average production due to the change in precipitation was approximately 1.1%. We concluded that the changes in temperature and precipitation decreased cotton yields in China, while beneficial effects of temperature and precipitation existed in the cotton-growing regions of Northwest China during 1961-2010.

关键词： climate change impact cotton yield provincial data China temperature precipitation

Water Cycle and Microphysical Processes Associated with a Mesoscale Convective Vortex System in the Dabie Mountain Area

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Advances in Atmospheric Sciences 2011年第6期28卷 1405-1422页

作者：汪小康倪允琪徐文慧顾春利邱学兴 School of Atmospheric Sciences Nanjing University institute of heavy rain China Meteorological Administration State Key Lab of Severe Weather Chinese Academy of Meteorological Sciences Beijing institute of Applied Meteorology Anhui Meteorological Observatory

The water vapor budget and the cloud microphysical processes associated with a heavy rainfall system in the Dabie Mountain area in June 2008 were analyzed using mesoscale reanalysis data（grid resolution 0.03 × 0.03,22 vertical layers,1-h intervals）,generated by amalgamating the local analysis and prediction system（LAPS）.The contribution of each term in the water vapor budget formula to precipitation was *** characteristics of water vapor budget and water substances in various phase states were evaluated and their differences in heavy and weak rainfall areas were *** precipitation calculated from the total water vapor budget accounted for 77% of actual precipitation;surface evaporation is another important source of water *** vapor within the domain of interest mainly came from the lower level along the southern boundary and the lower-middle level along the western *** altitude difference for water vapor flux was caused by different weather *** decrease of local water vapor in the middle-lower layer in the troposphere during the system development stage also contributed to *** strength and the layer thickness of water vapor convergence and the content of various water substances in the heavy rainfall areas were obviously larger than in the weak rainfall *** peak values of lower-level water vapor convergence,local water vapor income,and the concentration of cloud ice all preceded the heaviest surface rainfall by a few hours.

关键词： water vapor budget water substance SCHeREX data heavy rainfall

Calibration of the solar radio spectrometer

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Science China(Physics,Mechanics & Astronomy) 2009年第11期52卷 1760-1764页

作者： TAN ChengMing YAN YiHua TAN BaoLin XU GuiRong Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China institute of heavy rain China Meteorological AdministrationWuhan 430074China

This paper shows some improvements and new results of calibration of Chinese solar radio spectrometer by analyzing the daily calibration data recorded in the period of 1997-2007. First, the calibration coefficient is fitted for three bands (1.0-2.0 GHz, 2.6-3.8 GHz, 5.2-7.6 GHz) of the spectrometer by using the moving-average method confined by the property of the daily calibration data. By this calibration coefficient, the standard deviation of the calibration result was less than 10 sfu for 95% frequencies of 2.6-3.8 GHz band in 2003. This result is better than that calibrated with the constant coefficient. Second, the calibration coefficient is found in good correlation with local air temperature for most frequencies of 2.6-3.8 GHz band. Moreover, these results are helpful in the research of the quiet solar radio emission.

关键词： solar radio spectrometer calibration coefficient moving-average air temperature correlation

The Impacts of Moisture Transport of East Asian Monsoon on Summer Precipitation in Northeast China

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Advances in Atmospheric Sciences 2007年第4期24卷 606-618页

作者：孙力沈柏竹高枞亭隋波 Lesheng BAI Sheng-Hung WANG 安刚李健 institute of Meteorological Sciences of Jilin Province Changchun 130062 Wuhan institute of heavy rain Wuhan 430074 Polar Meteorology Group Byrd Polar Research Center The Ohio State University Columbus Ohio 43210 USA

By using the ECMWF reanalysis daily data and daily precipitation data of 80 stations in Northeast China from 1961 to 2002, the impacts of moisture transport of East Asian summer monsoon on the summer precipitation anomaly in Northeast China, and the relationship between the variation of moisture budget and the establishment of East Asian summer monsoon in this region are studied. The results demonstrate that the moisture of summer precipitation in Northeast China mainly originates from subtropical, South China Sea, and South Asia monsoon areas. East China and its near coastal area are the convergent region of the monsoonal moisture currents and the transfer station for the currents continually moving northward. The monsoonal moisture transport, as an important link or bridge, connects the interaction between middle and low latitude systems. In summer half year, there is a moisture sink in Northeast China where the moisture influx is greater than outflux. The advance transport and accumulation of moisture are of special importance to pentad time scale summer precipitation. The onset, retreat, and intensity change of the monsoonal rainy season over Northeast China are mainly signified by the moisture input condition along the southern border of this area. The establishment of East Asian summer monsoon in this area ranges from about 10 July to 20 August and the onset in the west is earlier than that in the east. The latitude that the monsoon can reach is gradually northward from west to east, reaching 50°N within longitude 120°-135°E. In summer, the difference of air mass transport between summers with high and low rainfall mainly lies in whether more air masses originating from lower latitudes move northward through East China and its coastal areas, consequently transporting large amounts of hot and humid air into Northeast China.

关键词： Northeast China East Asian monsoon moisture transport source-sink structure air mass trajectory