期刊文献+
共找到66篇文章
< 1 2 4 >
每页显示 20 50 100
Understanding Simulated Causes of Damaging Surface Winds in a Derecho-Producing Mesoscale Convective System near the East China Coast Based on Convection-Permitting Simulations
1
作者 Liping LUO Ming XUE +3 位作者 Xin XU Lijuan LI Qiang ZHANG Ziqi FAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第11期2112-2130,共19页
A mesoscale convective system(MCS) occurred over the East China coastal provinces and the East China Sea on 30April 2021, producing damaging surface winds near the coastal city Nantong with observed speeds reaching 45... A mesoscale convective system(MCS) occurred over the East China coastal provinces and the East China Sea on 30April 2021, producing damaging surface winds near the coastal city Nantong with observed speeds reaching 45 m s^(–1). A simulation using the Weather Research and Forecasting model with a 1.5-km grid spacing generally reproduces the development and subsequent organization of this convective system into an MCS, with an eastward protruding bow segment over the sea. In the simulation, an east-west-oriented high wind swath is generated behind the gust front of the MCS. Descending dry rear-to-front inflows behind the bow and trailing gust front are found to feed the downdrafts in the main precipitation regions. The inflows help to establish spreading cold outflows and enhance the downdrafts through evaporative cooling. Meanwhile, front-to-rear inflows from the south are present, associated with severely rearward-tilted updrafts initially forming over the gust front. Such inflows descend behind(north of) the gust front, significantly enhancing downdrafts and near-surface winds within the cold pool. Consistently, calculated trajectories show that these parcels that contribute to the derecho originate primarily from the region ahead(south) of the east-west-oriented gust front, and dry southwesterly flows in the low-to-middle levels contribute to strong downdrafts within the MCS. Moreover, momentum budget analyses reveal that a large westward-directed horizontal pressure gradient force within the simulated cold pool produced rapid flow acceleration towards Nantong. The analyses enrich the understanding of damaging wind characteristics over coastal East China and will prove helpful to operational forecasters. 展开更多
关键词 damaging surface winds convection-permitting simulations mesoscale convective system gust front cold pool
下载PDF
Recognition of Organizational Morphology of Mesoscale Convective Systems Using Himawari-8 Observations
2
作者 SHOU Yi-xuan ZHANG Su-zhao LU Feng 《Journal of Tropical Meteorology》 SCIE 2024年第3期289-305,共17页
The onset,evolution,and propagation processes of convective cells can be reflected by the organizational morphology of mesoscale convective systems(MCSs),which are key factors in determining the potential for heavy pr... The onset,evolution,and propagation processes of convective cells can be reflected by the organizational morphology of mesoscale convective systems(MCSs),which are key factors in determining the potential for heavy precipitation.This paper proposed a method for objectively classifying and segmenting MCSs using geosynchronous satellite observations.Validation of the product relative to the classification in radar composite reflectivity imagery indicates that the algorithm offers skill for discriminating between convective and stratiform areas and matched 65%of convective area identifications in radar imagery with a false alarm rate of 39%and an accuracy of 94%.A quantitative evaluation of the similarity between the structures of 50 MCSs randomly obtained from satellite and radar observations shows that the similarity was as high as 60%.For further testing,the organizational modes of the MCS that caused the heavy precipitation in Northwest China on August 21,2016(hereinafter known as the“0821”rainstorm)were identified.It was found that the MCS,accompanied by the“0821”rainstorm,successively exhibited modes of the isolated cell,squall line with parallel stratiform(PS)rain,and non-linear system during its life cycle.Among them,the PS mode might have played a key role in causing this flooding.These findings are in line with previous studies. 展开更多
关键词 mesoscale convective system SATELLITE organizational morphology extremely heavy precipitation
下载PDF
Evolution of the Total Lightning Activity in a Leading-Line and Trailing Stratiform Mesoscale Convective System over Beijing 被引量:19
3
作者 刘冬霞 郄秀书 +1 位作者 熊亚军 冯桂力 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2011年第4期866-878,共13页
Data from the Beijing SAFIR 3000 lightning detection system and Doppler radar provided some insights into the three-dimensional lightning structure and evolution of a leading-line and trailing-stratiform (LLTS) meso... Data from the Beijing SAFIR 3000 lightning detection system and Doppler radar provided some insights into the three-dimensional lightning structure and evolution of a leading-line and trailing-stratiform (LLTS) mesoscale convective system (MCS) over Beijing on 31 July 2007. Most of the lightning in the LLTS-MCS was intracloud (IC) lightning, while the mean ratio of positive cloud-to-ground (+CG) lightning to –CG lightning was 1:4, which was higher than the average value from previous studies. The majority of CG lightning occurred in the convective region of the radar echo, particularly at the leading edge of the front. Little IC lightning and little +CG lightning occurred in the stratiform region. The distribution of the CG lightning indicated that the storm had a tilted dipole structure given the wind shear or the tripole charge structure. During the storm’s development, most of the IC lightning occurred at an altitude of ~9.5 km; the lightning rate reached its maximum at 10.5 km, the altitude of IC lightning in the mature stage of the storm. When the thunderstorm began to dissipate, the altitude of the IC lightning decreased gradually. The spatial distribution of lightning was well correlated with the rainfall on the ground, although the peak value of rainfall appeared 75 min later than the peak lightning rate. 展开更多
关键词 mesoscale convective system cloud to ground (CG) lightning intracloud (IC) lightning SAFIR 3000
下载PDF
Simulation of Quasi-Linear Mesoscale Convective Systems in Northern China:Lightning Activities and Storm Structure 被引量:7
4
作者 Wanli LI Xiushu QIE +2 位作者 Shenming FU Debin SU Yonghai SHEN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第1期85-100,共16页
Two intense quasi-linear mesoscale convective systems(QLMCSs) in northern China were simulated using the WRF(Weather Research and Forecasting) model and the 3D-Var(three-dimensional variational) analysis system ... Two intense quasi-linear mesoscale convective systems(QLMCSs) in northern China were simulated using the WRF(Weather Research and Forecasting) model and the 3D-Var(three-dimensional variational) analysis system of the ARPS(Advanced Regional Prediction System) model.A new method in which the lightning density is calculated using both the precipitation and non-precipitation ice mass was developed to reveal the relationship between the lightning activities and QLMCS structures.Results indicate that,compared with calculating the results using two previous methods,the lightning density calculated using the new method presented in this study is in better accordance with observations.Based on the calculated lightning densities using the new method,it was found that most lightning activity was initiated on the right side and at the front of the QLMCSs,where the surface wind field converged intensely.The CAPE was much stronger ahead of the southeastward progressing QLMCS than to the back it,and their lightning events mainly occurred in regions with a large gradient of CAPE.Comparisons between lightning and non-lightning regions indicated that lightning regions featured more intense ascending motion than non-lightning regions;the vertical ranges of maximum reflectivity between lightning and non-lightning regions were very different;and the ice mixing ratio featured no significant differences between the lightning and non-lightning regions. 展开更多
关键词 quasi-linear mesoscale convective system Weather Research and Forecasting model Advanced Regional Prediction system model precipitation and non-precipitation ice
下载PDF
THE FORMATION AND DEVELOPMENT OF A MESOSCALE CONVECTIVE SYSTEM WITH HEAVY RAINFALL ALONG SOUTH CHINA COASTAL AREA 被引量:6
5
作者 蒙伟光 张艳霞 +1 位作者 戴光丰 闫敬华 《Journal of Tropical Meteorology》 SCIE 2008年第1期57-60,共4页
Observational analysis shows that a Mesoscale Convective System (MCS) occurred on May 13-14 2004 along the coastal area in South China. The MCS initiated among the southwesterly flows within a west-east orientation lo... Observational analysis shows that a Mesoscale Convective System (MCS) occurred on May 13-14 2004 along the coastal area in South China. The MCS initiated among the southwesterly flows within a west-east orientation low-level shear line. Associated with the system, in its subsequent development stages, no distinct vortex circulation developed in low-level. Instead, a cyclonic flow disturbance was observed in the mid-troposphere. How the convection starts to develop and evolve into a MCS With observational analysis and numerical simulation, the problem has been studied. The high-resolution MM5 simulation shows that topographic convergence along the coastal line and the nearby mountains in western South China plays an important role to initiate the MCS convection. Once the convection occurs, due to the condensation heating, a cooperative interaction between the preexisting mid-level disturbance and convection is created, which may greatly affect the MCS development during periods when the system continues moving eastward. Compared to some typical MCS that happen in Southern China, which are usually accompanied with upward development of cyclonic vorticity, the development and evolution of the investigated MCS shows distinguishing features. In this article, the physical mechanisms responsible for the intensification of mid-level disturbance are discussed, and a viewpoint to interpret the effects of mid-level disturbance on the MCS organizational development is proposed. 展开更多
关键词 topographic convergence mid-level disturbance mesoscale convective system (MCS) numericalsimulation
下载PDF
Analysis of a Mesoscale Convective System that Produced a Single Sprite 被引量:3
6
作者 Jing YANG Gaopeng LU +3 位作者 Ningyu LIU Haihua CU Yu WANG Morris COHEN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第2期258-271,共14页
Sprites are brief optical emissions occurring above thunderstorms. Features of sprites and their parent thunderstorms and lightning activities have been studied by many researchers. Here, we report a single sprite rec... Sprites are brief optical emissions occurring above thunderstorms. Features of sprites and their parent thunderstorms and lightning activities have been studied by many researchers. Here, we report a single sprite recorded over a mesoscale convective system during its life cycle in Northeast China. The results show that the sprite might have been a dancing one, with a 20 km horizontal displacement from its parent cloud-to-ground flash (CG) and a 38 ms time delay; all the sprite elements occurred during the continuing current process of the parent flash. The peak current of the parent CG was the largest during the almost one-hour time window containing the sprite, and the absolute values of all the negative flashes were smaller than 100 kA during the same time period and did not produce sprite. The sprite did not occur during the time period in which the maximum area of the thunderstorm reached. The occurrence of sprite corresponded well with the decay of the thunderstorm convection, and no significant relationship between the occurrence of sprite and the increase in the 30-35 dBZ and 35-40 dBZ interval was found. The large wind gradient in the 8-12 km region of the thunderstorm may have played an important role in the sprite production. 展开更多
关键词 SPRITE mesoscale convective system Doppler radar LIGHTNING magnetic field
下载PDF
A Numerical Case Study on a Mesoscale Convective System over the Qinghai-Xizang (Tibetan) Plateau 被引量:2
7
作者 朱国富 陈受钧 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2003年第3期385-397,共13页
A mesoscale convective system (MCS) developing over the Qinghai-Xizang Plateau on 26 July 1995 is simulated using the fifth version of the Penn State-NCAR nonhydrostatic mesoscale model (MM5). The results obtained are... A mesoscale convective system (MCS) developing over the Qinghai-Xizang Plateau on 26 July 1995 is simulated using the fifth version of the Penn State-NCAR nonhydrostatic mesoscale model (MM5). The results obtained are inspiring and are as follows. (1) The model simulates well the largescale conditions in which the MCS concerned is embedded, which are the well-known anticyclonic Qinghai-Xizang Plateau High in the upper layers and the strong thermal forcing in the lower layers. In particular, the model captures the meso-&#945; scale cyclonic vortex associated with the MCS, which can be analyzed in the 500 hPa observational winds; and to some degree, the model reproduces even its meso-&#946; scale substructure similar to satellite images, reflected in the model-simulated 400 hPa rainwater. On the other hand, there are some distinct deficiencies in the simulation; for example, the simulated MCS occurs with a lag of 3 hours and a westward deviation of 3–5° longitude. (2) The structure and evolution of the meso-&#945; scale vortex associated with the MCS are undescribable for upper-air sounding data. The vortex is confined to the lower troposphere under 450 hPa over the plateau and shrinks its extent with height, with a diameter of 4° longitude at 500 hPa. It is within the updraft area, but with an upper-level anticyclone and downdraft over it. The vortex originates over the plateau, and does not form until the mature stage of the MCS. It lasts for 3–6 hours. In its processes of both formation and decay, the change in geopotential height field is prior to that in the wind field. It follows that the vortex is closely associated with the thermal effects over the plateau. (3) A series of sensitivity experiments are conducted to investigate the impact of various surface thermal forcings and other physical processes on the MCS over the plateau. The results indicate that under the background conditions of the upper-level Qinghai-Xizang High, the MCS involved is mainly dominated by the low-level thermal forcing. The simulation described here is a good indication that it may be possible to reproduce the MCS over the plateau under certain large-scale conditions and with the incorporation of proper thermal physics in the lower layers. 展开更多
关键词 Qinghai-Xizang (Tibetan) Plateau mesoscale convective system (MCS) numerical simulation
下载PDF
Analysis and Comparison of Mesoscale Convective Systems over the Qinghai-Xizang (Tibetan) Plateau 被引量:2
8
作者 朱国富 陈受钧 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2003年第3期311-322,共12页
A series of mesoscale convective systems (MCSs) occurred daily over the Qinghai-Xizang Plateau during 25–28 July 1995. In this paper, their physical characteristics and evolutions based on infrared satellite imagery,... A series of mesoscale convective systems (MCSs) occurred daily over the Qinghai-Xizang Plateau during 25–28 July 1995. In this paper, their physical characteristics and evolutions based on infrared satellite imagery, their largescale meteorological conditions, and convective available potential energy (CAPE) are analyzed. It is found that similar diurnal evolution is present in all these MCSs. Their initial convective activities became active at noon LST by solar heating, and then built up rapidly. They formed and reached a peak in the early evening hours around 1800 LST and then abated gradually. Among them, the strongest and largest is the MCS on 26 July, which developed under the conditions of the great upper-level nearly-circular Qinghai-Xizang anticyclonic high and driven by the strong low-level thermal forcing and conditional instability. All these conditions are intimately linked with the thermal effects of the plateau itself. So its development was mainly associated with the relatively pure thermal effects peculiar to the Qinghai-Xizang Plateau. The next strongest one is the MCS on 28 July, which was affected notably by the baroclinic zone linked with the westerly trough. There are different features and development mechanisms between these two strongest MCSs. 展开更多
关键词 Qinghai-Xizang (Tibetan) Plateau mesoscale convective system (MCS) convective available potential energy (CAPE)
下载PDF
Numerical Simulation of Torrential Rainfall and Vortical Hot Towers in a Midlatitude Mesoscale Convective System 被引量:2
9
作者 ZHANG Man Da-Lin ZHANG WANG Ang-Sheng 《Atmospheric and Oceanic Science Letters》 2009年第4期189-193,共5页
A cloud-resolving model simulation of a mesoscale convective system (MCS) producing torrential rainfall is performed with the finest horizontal resolution of 444 m. It is shown that the model reproduces the observed... A cloud-resolving model simulation of a mesoscale convective system (MCS) producing torrential rainfall is performed with the finest horizontal resolution of 444 m. It is shown that the model reproduces the observed MCS, including its rainfall distribution and amounts, as well as the timing and location of leading rainbands and trailing stratiform clouds. Results show that discrete convective hot towers, shown in Vis5D at a scale of 2-5 kin, are triggered by evaporatively driven cold outflows converging with the high-θe air ahead. Then, they move rearward, with respect to the leading rainbands, to form stratiform clouds. These convective towers generate vortical tubes of opposite signs, with more intense cyclonic vorticity occurring in the leading convergence zone. The results appear to have important implications for the improvement of summertime quantitative precipitation forecasts and the understanding of vortical hot towers, as well midlevel mesoscale convective vortices. 展开更多
关键词 torrential rainfall mei-yu front vortical hot towers mesoscale convective systems
下载PDF
Initiation and Evolution of Long-Lived Eastward-Propagating Mesoscale Convective Systems over the Second-Step Terrain along Yangtze-Huaihe River Valley 被引量:1
10
作者 Yuanchun ZHANG Jianhua SUN +1 位作者 Ruyi YANG Ruoyun MA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2022年第5期763-781,共19页
Based on the previous statistical analysis of mesoscale convective systems(MCSs)over the second-step terrain along Yangtze-Huaihe River Valley,eight representative long-lived eastward-propagating MCSs are selected for... Based on the previous statistical analysis of mesoscale convective systems(MCSs)over the second-step terrain along Yangtze-Huaihe River Valley,eight representative long-lived eastward-propagating MCSs are selected for model-based sensitivity testing to investigate the initiation and evolution of these types of MCSs as well as their impact on downstream areas.We subject each MCS to a semi-idealized(CNTL)simulation and a sensitivity(NOLH)simulation that neglects condensational heating in the formation region.The CNTL experiment reveals convection forms in the region downstream of a shortwave trough typified by persistent southwesterly winds in the low-to midtroposphere.Upon merging with other convective systems,moist convection develops into an MCS,which propagates eastward under the influence of mid-tropospheric westerlies,and moves out of the second-step terrain.The MCS then merges with pre-existing local convection over the plains;the merged convection reinforces the cyclonic wind perturbation into a mesoscale vortex at 850 hPa.While this vortex moves eastward to regions with local vortex at 850 hPa,another vortex at 925 hPa is also intensified.Finally,the vortices at 850 and 925 hPa merge together and develop into a mesoscale convective vortex(MCV).In contrast,MCSs fail to form and move eastward in the NOLH experiment.In the absence of eastward-propagating MCSs,moist convection and mesoscale vortices still appear in the plains,but the vortex strength and precipitation intensity are significantly weakened.It is suggested the eastward-propagating MCSs over the second-step terrain significantly impact the development and enhancement of moist convection and vortices in the downstream areas. 展开更多
关键词 mesoscale convective systems second-step terrain mesoscale convective vortex numerical sensitivity simulation
下载PDF
ANALYSIS OF MESOSCALE CONVECTIVE SYSTEMS OVER TIBETAN PLATEAU IN SUMMER 被引量:1
11
作者 GUO Zhong-yang DAI Xiao-yan +1 位作者 WU Jian-ping LIN Hui 《Chinese Geographical Science》 SCIE CSCD 2006年第2期116-121,共6页
In this paper, Geostationary Meteorological Satellite (GMS) infrared black-body temperature (Tbb) data from June to August 1998 are used to automatically track the activity of Mesoscale Convective System (MCS) over th... In this paper, Geostationary Meteorological Satellite (GMS) infrared black-body temperature (Tbb) data from June to August 1998 are used to automatically track the activity of Mesoscale Convective System (MCS) over the Tibetan Plateau in China. Consequently, the features of MCS, such as area, intensity, life cycle, activity region and shape, are obtained. High Resolution Limited Area Analysis and Forecasting System (HLAFS) values provided by China National Meteorological Center are used to study the relationships between the MCS trajectories and their environmental physical field values, based on the distribution and trajectories of MCSs over the Tibetan Plateau. Favorable environmental physical field charts of influencing MCS movement out of the Tibetan Plateau in different UTC (Universal Time Coordinate) are developed by using spatial data mining techniques at levels of 400hPa and 500hPa, respectively. 展开更多
关键词 Tibetan Plateau mesoscale convective systems black-body temperature automatically tracking
下载PDF
MAGE ANALYSIS OF GEOSTATIONARY METEOROLOGICAL SATELLITE FOR MONITORING MOVEMENT OF MESOSCALE CONVECTIVE SYSTEMS OVER TIBETAN PLATEAU 被引量:1
12
作者 DAI Xiao-yan WU Jian-ping LIN Hui 《Chinese Geographical Science》 SCIE CSCD 2005年第3期231-237,共7页
Disaster weather forecasting is becoming increasingly important. In this paper, the trajectories of Mesoscale Convective Systems (MCSs) were automatically tracked over the Chinese Tibetan Plateau using Geostationary... Disaster weather forecasting is becoming increasingly important. In this paper, the trajectories of Mesoscale Convective Systems (MCSs) were automatically tracked over the Chinese Tibetan Plateau using Geostationary Meteorological Satellite (GMS) brightness temperature (Tbb) from June to August 1998, and the MCSs are classified according to their movement direction. Based on these, spatial data mining methods are used to study the relationships between MCSs trajectories and their environmental physical field values. Results indicate that at 400hPa level, the trajectories of MCSs moving across the 105°E boundary are less influenced by water vapor flux divergence, vertical wind velocity, reIative humidity and K index. In addition, if the gravity central longitude locations of MCSs are between 104°E and 105°E, then geopotential height and wind divergence are two main factors in movement causation. On the other hand, at 500hPa level, the trajectories of MCSs in a north-east direction are mainly influenced by K index and water vapor flux divergence when their central locations are less than 104°E. However, the MCSs moving in an east and south-east direction are influenced by a few correlation factors at this level. 展开更多
关键词 Tibetan Plateau mesoscale convective systems automatically tracking spatial data mining
下载PDF
EFFECTS OF CONDENSATION HEATING AND SURFACE FLUXES ON THE DEVELOPMENT OF A SOUTH CHINA MESOSCALE CONVECTIVE SYSTEM (MCS) 被引量:1
13
作者 蒙伟光 李江南 +3 位作者 王安宇 冯瑞权 古志明 闫敬华 《Journal of Tropical Meteorology》 SCIE 2005年第2期144-153,共10页
A sensitive numerical simulation study is carded out to investigate the effects of condensation heating and surface fluxes on the development of a South China MCS that occurred during 23 - 24 May 1998. The results rev... A sensitive numerical simulation study is carded out to investigate the effects of condensation heating and surface fluxes on the development of a South China MCS that occurred during 23 - 24 May 1998. The results reveal the following: (1) Condensation heating plays an important role in the development of MCS. In every different stage, without condensation heating, MCS precipitation is significantly reduced, and quickly dissipates. (2) Condensation heating demonstrates most importantly during the early development stages of MCS vortex; as the vortex develops stronger, the condensation heating effects reduces. (3) By affecting the MCS development processes, condensation heating also influences the formation of MCS mesoscale environment structure features such as low-level jet (mLLJ), upper-level divergence. (4) By changing the antecedent environmental circulation, the surface fluxes also play an important role in the development of MCS. Because of the surface heating, pressure declines over the heavy rainfall and MCS happening regions, which results in the intensification of southerly flows from the ocean along the South China coastline areas, and leads to the enhancement of horizontal convergence and increase of vapor amount in the lower layer. All of these make the atmosphere more unstable and more favorable for the convection. 展开更多
关键词 condensation heating surface fluxes mesoscale convective system (MCS) South China heavyrainfall numerical simulation
下载PDF
The Characteristics of Mesoscale Convective Systems (MCSs) over East Asia in Warm Seasons 被引量:5
14
作者 Li Jun Wang Bin Wang Dong-Hai 《Atmospheric and Oceanic Science Letters》 2012年第2期102-107,共6页
Mesoscale convective system (MCS) cloud clusters,defined using an objective recognition analysis based on hourly geostationary infrared satellite data over East Asia during the warm seasons of 1996-2008 (except 2004),... Mesoscale convective system (MCS) cloud clusters,defined using an objective recognition analysis based on hourly geostationary infrared satellite data over East Asia during the warm seasons of 1996-2008 (except 2004),were investigated in this study.The geographical pattern of MCS distribution over East Asia shows several high-frequency centers at low latitudes,including the Indo-China peninsula,the Bay of Bengal,the Andaman Sea,the Brahmaputra river delta,the south China coastal region,and the Philippine Islands.There are several middle-frequency centers in the middle latitudes,e.g.,the central-east of the Tibet Plateau,the Plateau of west Sichuan,Mount Wuyi,and the Sayan Mountains in Russia;whereas in Lake Baikal,the Tarim Basin,the Taklimakan Desert,the Sea of Japan,and the Sea of Okhotsk,rare MCS distributions are observed.MCSs are most intensely active in summer,with the highest monthly frequency in July,which is partly associated with the breaking out and prevailing of the summer monsoon in East Asia.An obvious diurnal cycle feature is also found in MCS activities,which shows that MCSs are triggered in the afternoon,mature in the evening,and dissipate at night.MCS patterns over East Asia can be characterized as small,short-lived,or elongated,which move slowly and usually lead to heavy rains or floods. 展开更多
关键词 mesoscale convective system infrared satellite data DISTRIBUTION monthly variation diurnal cycle
下载PDF
Simulation of the evolution of the latent heat processes in a mesoscale convective system accompanied by heavy rainfall over the Guangzhou region of South China
15
作者 LI Jiang-Nan WU Kai-Lu +4 位作者 DING Cheng-Hui YANG Chao-Feng LI Fang-Zhou WANG Dong-Hai FENG Ye-Rong 《Atmospheric and Oceanic Science Letters》 CSCD 2017年第1期58-64,共7页
A cloud-scale WRF simulation was used to investigate the cloud microphysical processes and threedimensional structure of latent heat budgets in different stages of a mesoscale convective system(MCS) accompanied by h... A cloud-scale WRF simulation was used to investigate the cloud microphysical processes and threedimensional structure of latent heat budgets in different stages of a mesoscale convective system(MCS) accompanied by heavy rain that occurred in the Guangzhou region of South China.The results enable us to draw the following conclusions:(1) During the development and mature stages,the main heating processes were condensation below 400 hPa and deposition above 400 hPa.The main cooling processes were evaporation and melting.During the dissipation stage,all the microphysical processes were weak.(2) Water vapor condensed into cloud water,and rainwater significantly contributed to all stages of the MCS.(3) During every stage of the MCS,the primary cooling microphysical process was the evaporation of rainwater,which was maximum during the mature stage. 展开更多
关键词 mesoscale convective system microphysical process latent heat budget
下载PDF
Understanding the Split Characteristics of the Tropical Mesoscale Convective System (MCS) of April 9, 2018, in Northern Ghana Using Infrasound Data
16
作者 K. Benjamin Kouassi Fidele Yoroba +3 位作者 Uchenna Onwuhaka Madu Adama Diawara Kouakou Kouadio Paul Antoine Yao 《Atmospheric and Climate Sciences》 2021年第1期1-10,共10页
The split characteristics of the tropical Mesoscale Convective System (MCS) of April 9, 2018, in northern Ghana were studied using infrasound data measured by the mobile array (I68CI) which was deployed by C<span s... The split characteristics of the tropical Mesoscale Convective System (MCS) of April 9, 2018, in northern Ghana were studied using infrasound data measured by the mobile array (I68CI) which was deployed by C<span style="white-space:nowrap;">?</span>te d’Ivoire National Data Center (NDC) in collaboration with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). These infrasound measurements were made during a measurement campaign from January 1st, 2018 to December 31, 2018, in northeast Cote d’Ivoire, precisely in Comoe National Park. Graphic Progressive Multi-Channel Correlation (GPMCC) method based on a progressive study of the correlation functions was used to analyze and visualize data. The infrasound detection from this MCS shows clearly a division of the MCS structure into 2 distinct subsystems under the effect of internal and external constraints not well known but related to convection;a smaller subsystem in the north, associated with an area of intense rainfall of about 30 mm/hour and located at 9.5<span style="white-space:nowrap;">°</span>N - 2<span style="white-space:nowrap;">°</span>E with an azimuth of 70<span style="white-space:nowrap;">°</span> and, a large subsystem in the south, associated with a zone of high rainfall of about 96 mm/hour and located at 8.8<span style="white-space:nowrap;">°</span>N - 1.4<span style="white-space:nowrap;">°</span>E with an azimuth of 90<span style="white-space:nowrap;">°</span>. These two subsystems were located 200 km and 260 km from the I68CI station with frequencies of 2.3 Hz and 1 Hz respectively. The mesoscale convective systems in this region are moving from East to West and including several storm cells. 展开更多
关键词 INFRASOUND mesoscale convective systems (MCS) Cote D’Ivoire Satellite Image
下载PDF
SENSITIVITY OF MESOSCALE CONVECTIVE SYSTEMS AND ASSOCIATED HEAVY RAINFALL TO SOIL MOISTURE OVER SOUTH CHINA 被引量:1
17
作者 蒙伟光 张艳霞 +3 位作者 李江南 戴光丰 李昊睿 黄燕燕 《Journal of Tropical Meteorology》 SCIE 2017年第1期91-102,共12页
The impacts of soil moisture(SM) on heavy rainfall and the development of Mesoscale Convection Systems(MCSs) are investigated through 24-h numerical simulations of two heavy rainfall events that occurred respectively ... The impacts of soil moisture(SM) on heavy rainfall and the development of Mesoscale Convection Systems(MCSs) are investigated through 24-h numerical simulations of two heavy rainfall events that occurred respectively on28 March 2009(Case 1) and 6 May 2010(Case 2) over southern China. The numerical simulations were carried out with WRF and its coupled Noah LSM(Land Surface Model). First, comparative experiments were driven by two different SM data sources from NCEP-FNL and NASA-GLDAS. Secondary, with the run driven by NASA-GLDAS data as a control one, a series of sensitivity tests with different degree of(20%, 60%) increase or decrease in the initial SM were performed to examine the impact of SM on the simulations. Comparative experiment results show that the 24-h simulated cumulative rainfall distributions are not substantially affected by the application of the two different SM data,while the precipitation intensity is changed to some extent. Forecast skill scores show that simulation with NASA-GLDAS SM data can lead to some improvement, especially in the heavy rain(芏50 mm) forecast, where there is up to 5% increase in the TS score. Sensitivity test analysis found that a predominantly positive feedback of SM on precipitation existed in these two heavy rain events but not with completely the same features. Organization of the heavy rainfall-producing MCS seems to have an impact on the feedback process between SM and precipitation. For Case 1, the MCS was poorly organized and occurred locally in late afternoon, and the increase of SM only caused a slight enhancement of precipitation. Drier soil was found to result in an apparent decrease of rainfall intensity,indicating that precipitation is more sensitive to SM reduction. For Case 2, as the heavy rain was caused by a well-organized MCS with sustained precipitation, the rainfall is more sensitive to SM increase, which brings more rainfall. Additionally, distinctive feedback effects were identified from different stages and different organization of MCS, with strong feedback between SM and precipitation mainly appearing in the early stages of the poorly organized MCS and during the late period of the well-organized MCS. 展开更多
关键词 soil moisture Southern China heavy rainfall mesoscale Convection system numerical simulation
下载PDF
Potential Deformation and Its Application to the Diagnosis of Heavy Precipitation in Mesoscale Convective Systems 被引量:2
18
作者 Na LI Lingkun RAN +1 位作者 Linna ZHANG Shouting GAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第7期894-908,共15页
Many observational studies have shown that deformation, like vertical vorticity and divergence, is closely related to the occurrence and distribution of strong precipitation. In this paper, to involve deformation in p... Many observational studies have shown that deformation, like vertical vorticity and divergence, is closely related to the occurrence and distribution of strong precipitation. In this paper, to involve deformation in precipitation diagnosis, a new parameter called potential deformation(PD) is derived and then applied to precipitation detection within a simulated mesoscale convective system(MCS). It is shown that PD includes both stretching deformation and shearing deformation and shares similar characteristics with deformation insofar as it does not change with the rotating coordinate. Diagnosis of the simulated MCS reveals that PD performs well in tracing the MCS' precipitation. In terms of their distributional pattern, the large-value areas of PD are similar to the precipitation in the different development stages of the MCS. A detailed analysis of the physical processes contained within the PD shows that it can reflect the three-dimensional moisture variation,vertical wind shear and wind deformation within the MCS. These structures are usually a comprehensive reflection of the characteristics of the surface cold pool, rear inflow jet, downward cold air flow and upward warm moist flow within the precipitating convective cells. For this reason, the PD shows much stronger anomalies in the precipitating atmosphere than the non-precipitating atmosphere, which implies considerable potential for its application in detecting heavy precipitation within MCSs. 展开更多
关键词 Precipitation convective vorticity moisture divergence mesoscale observational stretching downward coordinate
下载PDF
The Contribution of Mesoscale Convective Systems to Intense Hourly Precipitation Events during the Warm Seasons over Central East China 被引量:1
19
作者 Zhiwei HE Qinghong ZHANG Jun SUN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第11期1233-1239,共7页
Central East China is an area where both intense hourly precipitation(IHP) events and mesoscale convection systems(MCSs) occur frequently in the warm seasons. Based on mosaics of composite Doppler radar reflectivi... Central East China is an area where both intense hourly precipitation(IHP) events and mesoscale convection systems(MCSs) occur frequently in the warm seasons. Based on mosaics of composite Doppler radar reflectivity and hourly precipitation data during the warm seasons(May to September) from 1 July 2007 to 30 June 2011, the contribution of MCSs to IHP events exceeding 20 mm h^-1 over central East China was evaluated. An MCS was defined as a continuous or quasicontinuous band of 40d BZ reflectivity that extended for at least 100 km in at least one direction and lasted for at least 3h. It was found that the contribution of MCSs to IHP events was 45% on average over central East China. The largest contribution,more than 80%, was observed along the lower reaches of the Yellow River and in the Yangtze River–Huaihe River valleys.These regions were the source regions of MCSs, or along the frequent tracks of MCSs. There were two daily peaks in the numbers of IHP events: one in the late afternoon and one in the early morning. These peaks were more pronounced in July than in other months. MCSs contributed more to the early-morning IHP event peaks than to the late-afternoon peaks. The contributions of MCSs to IHP events with different intensities exhibited no significant difference, which fluctuated around 50% on average over central East China. 展开更多
关键词 afternoon morning reflectivity Precipitation contributions Yangtze convection mesoscale Events exceeding
下载PDF
OBSERVATION AND MODEL ANALYSES OF POSITIVE CLOUD-TO-GROUND LIGHTNING IN MESOSCALE CONVECTIVE SYSTEMS 被引量:16
20
作者 Yan Muhong Guo Changming Qie Xiushu Ge Zhengmo Zhang Guangshu Lanzhou Institute of Plateau Atmospheric Physics,Academia Sinica,Lanzhou 730000 《Acta meteorologica Sinica》 SCIE 1992年第4期501-510,共10页
The analyses of spatial and temporal characteristics of positive cloud-to-ground(CG)lightning for four mesoscale convective systems and two severe local convective systems in 1989 and 1990 show that positive CG flash ... The analyses of spatial and temporal characteristics of positive cloud-to-ground(CG)lightning for four mesoscale convective systems and two severe local convective systems in 1989 and 1990 show that positive CG flash rate usually has two peak values.The major peak occurs during the developing stage of the storm and most of the positive CG flashes originate at the lower part of the storm.The minor occurs during the dissipative stage of the storm and most of the positive CG flashes originate at the upper part of the storm,especially in the region of the wind divergence in the storm anvil.The positive CG flash rate is almost an order of magnitude larger in the developing stage than in the dissipative stage.The appearing time of the peak of negative CG flash rate is in accordance with that of the valley of pos- itive CG flash rate. The higher the intensity of the radar echo,the higher the positive CG flash rate.Most of the positive CG flashes oc- cur when the weak echo area is larger,and mostly originate in the region where the radar echo intensity is about 10dBz and in the back region of the moving storms.The spatial distribution of the positive CG flashes is much more dispersive than that of the negative.The mesoscale analysis reveals a bipolar lightning pattern.The mean bipole--length reaches its minimum during the mature stage of the storm and reaches the maximum during the developing stage of the storm. The vertical distribution of the charge density is calculated by a one-dimensional charging model.Then,we discuss the producing condition of the positive CG lightning and forming cause of charge structure mentioned above. 展开更多
关键词 mesoscale convective systems THUNDERSTORM LIGHTNING ELECTRIFICATION
原文传递
上一页 1 2 4 下一页 到第
使用帮助 返回顶部