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1.
应用1949—2016年台风资料和中国地面逐日降水资料,针对中国内陆西部地区,通过对较长样本资料的统计分析,研究台风活动及其在台风登陆背景下,中国西部年、夏半年和盛夏平均降水特征。研究得到:①67年间登陆中国大陆的台风年平均9.09个,6—10月是台风活跃期,登陆台风最早在4月,最晚在12月,8月登陆台风频率最高。②台风活动对宁夏全省、陕西大部、四川盆地、甘肃中东部和青海大部降水影响明显,台风活动多寡与该地区降水多寡总体成正相关。新疆和西藏降水受台风影响极小,贵州、重庆降水与台风活动呈相反情况,台风活动对云南降水影响不明显。③台风活动与中国西部部分地区降水呈正相关特征,其年均降水最明显,其次是6—10月平均降水。此项研究首次聚焦在远距离台风与中国西部降水特征上,将有助于系统全面地认识台风活动特征、登陆台风与中国西部降水的关系以及中国西部降水机理。 相似文献
2.
运用中尺度数值模式WRF耦合城市冠层模式（urban canopy model,UCM）,对2016年登陆深圳的热带气旋妮妲（1604）（以下简称妮妲）进行数值模拟。高分辨率数值模拟较好地再现了妮妲登陆前后的强度、路径和累积降水。利用城市化过程当中城市冠层对热带气旋降水的敏感性试验结果表明:城市冠层会减弱对流运动和水汽的输送,导致热带气旋登陆后珠江口城市群区域累积降水量略减少。应用最新的土地利用资料进行的城市下垫面敏感性试验结果表明:由于城市下垫面粗糙度增加,造成登陆地面风的减速,强度减弱,潜热通量与2 m高度比湿相应减小;城市下垫面粗糙度增加会加强该区域垂直对流运动以及不稳定能量增加,有利于降水增强,尤其在城市化下垫面处,热带气旋登陆后6 h累积降水增加量最大可超过20 mm。总体而言,对登陆热带气旋降水而言,耦合城市冠层使城市区域热带气旋降水减少,但在数值模拟中城市冠层影响作用不显著。城市化下垫面对登陆热带气旋暴雨的增幅作用明显,在登陆热带气旋降水预报中应重视。 相似文献
3.
Estimating tropical cyclone precipitation from station observations 总被引：31，自引：0，他引：31
In this paper, an objective technique for estimating the tropical cyclone （TC） precipitation from station observations is proposed. Based on a comparison between the Original Objective Method （OOM） and the Expert Subjective Method （ESM）, the Objective Synoptic Analysis Technique （OSAT） for partitioning TC precipitation was developed by analyzing the western North Pacific （WNP） TC historical track and the daily precipitation datasets. Being an objective way of the ESM, OSAT overcomes the main problems in OOM, by changing two fixed parameters in OOM, the thresholds for the distance of the absolute TC precipitation （D0） and the TC size （D1）, into variable parameters.
Case verification for OSAT was also carried out by applying CMORPH （Climate Prediction Center MORPHing technique） daily precipitation measurements, which is NOAA＇s combined satellite precipitation measurement system. This indicates that OSAT is capable of distinguishing simultaneous TC precipitation rain-belts from those associated with different TCs or with middle-latitude weather systems. 相似文献
Case verification for OSAT was also carried out by applying CMORPH （Climate Prediction Center MORPHing technique） daily precipitation measurements, which is NOAA＇s combined satellite precipitation measurement system. This indicates that OSAT is capable of distinguishing simultaneous TC precipitation rain-belts from those associated with different TCs or with middle-latitude weather systems. 相似文献
4.
Using 1°×1° final analysis(FNL) data from the National Centers for Environmental Prediction(NCEP),precipitation data from the Tropical Rainfall Measuring Mission(TRMM) and the best-track tropical cyclone(TC)dataset provided by the Japan Meteorological Agency(JMA) for June-August of 2000-2009, we comprehensively consider the two factors low-level moisture channel and interaction between TCs and mid-latitude systems and implement a statistical analysis of remote precipitation in East Asia to the north of 0° and to the west of 150° E. 48 cases of remote precipitation occurred in this period, which are categorized into five classes. After a composite analysis of the different classes, the main systems at 850 h Pa and 500 h Pa that impact the remote precipitation are as follows:TC, mid-latitude trough, subtropical high and water vapor channel. In particular, the water vapor channel which usually connects with Indian monsoon has the most significant impact on remote heavy rainfall. Another important factor is the mid-latitude trough. The type of north trough/vortex-south TC remote precipitation events happen most frequently,accounting for 68.8% of the total incidence. Most remote precipitation events occur on the right side of the TC path(representing 71% of the total number). At 200 h Pa, the remote precipitation events usually occur on the right rear portion of a high-altitude jet stream, and there is an anti-cyclonic vortex to the east and west of the TCs. When there is no anti-cyclonic vortex to the east of the TC, the TC is relatively weak. When the remote precipitation occurs to the northwest of the TC and there is a trough in the northwest direction, the TC is relatively strong. Numerical experiments are carried out using Weather Research and Forecast(WRF) model. The results shows that the TC plays a main role in producing the heavy precipitation and results in the enhancement of precipitation by impacting the water vapor channel. 相似文献
5.
6.
Observation from automatic weather stations, radars and TRMM satellites are employed
to investigate the precipitation distribution of tropical cyclone (TC) Koppu (0915) that made
landfall on Guangdong province in 2009. The results show that the precipitation of landfall TC
Koppu is featured by significant asymmetry and mesoscale structure, and occurs mainly to the
left of its moving path. By examining the sea surface temperature (SST), water vapor flux, Q
vector, vertical wind shear of environment etc., it is found out that the distribution of SST,
water vapor convergence, low-level convective ascending and vertical wind shear facilitates
the TC precipitation to take place to the left of the TC moving path. The mesoscale structure
separated by Barnes band-pass filter presents that the precipitation of landfall KOPPU has
some organized mesoscale spiral structures, which is around the TC center and composed of the
form of belts or blocks. The heavy local rainfall of landfall TC Koppu is primarily associated
with the rainfall due to mesoscale spiral structure. 相似文献
7.
三个路径相似降雨特征不同的热带气旋分析 总被引：7，自引：2，他引：7
比照路径相似台风的降雨制作台风降雨预报是台风业务预报的常规方法之一。但台风飞燕、桃芝及一次热带低庄路径虽极为相似，它们的降雨强度和降雨分布则差异很大。通过对台风飞燕、桃芝及一次热带低压的大气环流形势特征、物理量场诊断结果和卫星云图的对比分析，发现热带气旋影响地的前期环境场、热带气旋影响期间西风带低槽和副热带高压的强弱及其相互配置以及它们与热带气旋的相互作用是造成路径相似的三个热带气旋出现降雨差异的主要原因。该分析结果对台风降雨的业务预报有实际意义。 相似文献
8.
利用1949—2009年热带气旋降水资料分析了全国热带气旋降水的时空分布特征。结果表明,全国各地区热带气旋降水的空间分布很不均匀,大致呈现东南—西北向的梯度分布,东南沿海地区降水量最大,西北内陆地区最小。另外,地形对降水的空间分布也有影响,例如东南沿海和山脉迎风坡的地形作用尤为显著。此外,比较不同年份的热带气旋降水的空间分布特征,有很多相似之处,如随经纬度的变化趋势,降水最大中心位置等。热带气旋降水具有比较明显的年代变化和显著的年际震荡。年代变化表现为20世纪50—60年代为大幅增加的过程,60—80年代降水总量基本维持,80年代后期降水呈现明显的震荡趋势。 相似文献
9.
全球变暖背景下我国极端小时降水和极端日降水(EXHP、EXDP)气候态及变化趋势的区域差异明显,其中热带气旋(TC)的影响尚不明确。利用1975─2018年暖季台站小时降水(P)和热带气旋最佳路径等资料,采用百分位法定义极端小时降水与极端日降水,并将总降水(All)客观分为热带气旋降水与非热带气旋(nonTC)降水,分析热带气旋对中国东部All-P、All-EXHP、All-EXDP的气候态和变化趋势以及极端小时降水随温度变化的影响。主要结论如下：(1) TC-P、TC-EXDP、TC-EXHP占其对应总降水之比均从东南和华南沿海向西北内陆递减,区域平均而言,TC-P占All-P之比与TC-EXHP占All-EXHP之比均约为11%,而TC-EXDP占AllEXDP之比为15.8%;(2)热带气旋和非热带气旋降水变化趋势的空间分布差别较大,热带气旋对长江流域东部总降水增多的贡献高达49%,并一定程度上改变了降水趋势的空间分布;(3) TC-EXHP强度与温度的关系在约21℃发生改变,且截然不同于nonTC-EXHP,华南、东南沿海TC-EXHP强度随温度的变化率明显低于nonTCEXH... 相似文献
10.
选取我国东南沿海热带气旋登陆数目多、经济发达的浙江和福建两省,利用国家级地面气象站逐小时降水观测资料,结合热带气旋降水客观分离方法,对1956~2012年（共57年）浙、闽两省沿海登陆热带气旋降水开展客观分离,统计分析热带气旋登陆期间降水精细化时空分布特征。结果表明:热带气旋平均路径在登陆前6小时至登陆后24小时呈西北行,累积降水具有明显非对称分布特征,与主要水汽辐合区相吻合,登陆后24小时至48小时的降水分布与鄱阳湖水体以及局地地形有密切联系;伴随登陆进程,降水分布呈现显著变化,登陆前,浙、闽两省降水较强;登陆后,降水范围向内陆扩展到浙、闽两省以外地区;登陆点聚类分析指出,所有类别的较强降水时段均位于登陆前12小时至登陆后6小时,但不同类别的降水分布和演变特征具有显著差异,这种差异与局地地形和热带气旋环流所处位置关系密切;小时强降水统计分析显示,伴随着登陆进程强降水频次分布逐渐变化和向内陆地区推进,高频次强降水主要出现在登陆前、后6小时的浙、闽两省沿海地区,且以两省交界附近地区最为集中,与该地区明显的高大地形分布有着密切的关系。两省各台站由登陆热带气旋带来的小时降水极值差异较大,从10到143 mm均有分布,大部分极值在30至60 mm之间。其中,极值大于50 mm的站点主要分布在沿海地区,在浙、闽交界处较为集中,与小时强降水的频次分布一致。 相似文献
11.
In order to provide an operational reference for tropical cyclone precipitation forecast,this study investigates the spatial distributions of precipitation associated with landfalling tropical cyclones(TCs) affecting China using Geostationary Meteorological Satellite 5(GMS5)-TBB dataset.All named TCs formed over the western North Pacific that made direct landfall over China during the period 2001-2009 are included in this study.Based on the GMS5-TBB data,this paper reveals that in general there are four types of distribution of precipitation related to landfalling TCs affecting China.(a) the South-West Type in which there is a precipitation maximum to the southwestern quadrant of TC;(b) the Symmetrical South Type in which the rainfall is more pronounced to the south side of TC in the inner core while there is a symmetrical rainfall distribution in the outer band region;(c) the South Type,in which the rainfall maxima is more pronounced to the south of TC;and(d) the North Type,in which the rainfall maxima is more pronounced to the north of TC.Analyses of the relationship between precipitation distributions and intensity of landfalling TCs show that for intensifying TCs,both the maximum and the coverage area of the precipitation in TCs increase with the increase of TC intensity over northern Jiangsu province and southern Taiwan Strait,while decreasing over Beibu Gulf and the sea area of Changjiang River estuary.For all TCs,the center of the torrential rain in TC shifts toward the TC center as the intensity of TC increases.This finding is consistent with many previous studies.The possible influences of storm motion and vertical wind shear on the observed precipitation asymmetries are also examined.Results show that the environmental vertical wind shear is an important factor contributing to the large downshear rainfall asymmetry,especially when a TC makes landfall on the south and east China coasts.These results are also consistent with previous observational and numerical studies. 相似文献
12.
西北太平洋热带气旋(TC)是影响中国降水的重要天气系统,其减弱后的残留低压(TCRL)仍然携带大量的水汽和能量,给其经过之处带来强降水。为分析热带气旋残留低压对中国降水的影响,采用客观方法从ERA-40和ERA-Interim再分析资料中识别出热带气旋对应的气旋,从而得到热带气旋残留低压活动资料。将残留低压的活动路径分为东北路径、东南沿海路径和西行路径3类,采用客观天气图分析法(OSAT)得到残留低压影响下的降水分布,对残留低压的活动路径和降水的分析结果表明,文中采用的方法能追踪得到热带气旋的完整生命史,在1958-2014年进入警戒区的718个热带气旋中,追踪得到706个对应的气旋,追踪的气旋中心与热带气旋中心平均距离131 km;共443个热带气旋有对应的残留低压,平均持续时间48.5 h,1 d以上的残留低压共293个,占66.1%,残留低压的持续时间与对应的热带气旋强度没有显著的关系,夏季残留低压持续时间较冬季长;对内陆地区的影响残留低压较热带气旋更为显著,降水影响自东南向西北减少,影响范围较热带气旋西扩,强度更大;东北路径主要进入地区为东北和华东地区,影响中国东部地区的降水;东南沿海路径影响范围最广,影响降水的强度最大;西行路径进入范围仅华南和西南地区,主要影响中国南部地区的降水,降水强度最小。 相似文献
13.
We investigate the effects of sea-salt aerosol(SSA) activated as cloud condensation nuclei on the microphysical processes, precipitation, and thermodynamics of a tropical cyclone(TC). The Weather Research and Forecasting model coupled with Chemistry(WRF-Chem) was used together with a parameterization of SSA production. Three simulations, with different levels of SSA emission(CTL, LOW, HIGH), were conducted. The simulation results show that SSA contributes to the processes of autoconversion of cloud water and accretion of cloud water by rain,thereby promoting rain formation. The latent heat release increases with SSA emission, slightly increasing horizontal wind speeds of the TC. The presence of SSA also regulates the thermodynamic structure and precipitation of the TC.In the HIGH simulation, higher latent heat release gives rise to stronger updrafts in the TC eyewall area, leading to enhanced precipitation. In the LOW simulation, due to decreased latent heat release, the temperature in the TC eye is lower, enhancing the downdrafts in the region; and because of conservation of mass, updrafts in the eyewall also strengthen slightly; as a result, precipitation in the LOW experiment is a little higher than that in the CTL experiment.Overall, the relationship between the precipitation rate and SSA emission is nonlinear. 相似文献
14.
Tropical cyclone extreme rainfall(TCER)causes devastating floods and severe damage in China and it is therefore important to determine its long-term climatological distribution for both disaster prevention and operational forecasting.Based on the tropical cyclone(TC)best-track dataset and TC precipitation data from 1960 to 2019,the spatiotemporal distribution of TCER affecting China is analyzed.Results show that there were large regional differences in the threshold for TCER in China,decreasing from the southeastern coast to the northwest inland.TCER occurred infrequently in northern China but had a high intensity and was highly localized.The frequency and intensity of TCER showed slightly increasing trends over time and was most likely to occur in August(41.0%).Most of the TC precipitation processes with extreme rainfall lasted for four to six days,with TCER mainly occurring on the third to fourth days.TCER with wide areas showed a northwestward prevailing track and a westward prevailing track.Strong TCs are not always accompanied by extreme precipitation while some weak TCs can lead to very extreme rainfall.A total of 64.7%(35.3%)of the TCER samples occurred when the TC was centered over the land(sea).TCER≥250 mm was located within 3°of the center of the TC.When the center of the TC was located over the sea(land),the extreme rainfall over land was most likely to appear on its northwestern(northeastern)side with a dispersed(concentrated)distribution.TCER has unique climatic characteristics relative to the TC precipitation. 相似文献
15.
针对中国热带气旋(Tropical Cyclone,简称TC)降水的分离问题,利用国家气候中心任福民等提出的客观天气图分析法(Objective Synoptic Analysis Technique,简称OSAT)对2005年影响我国强度达到台风以上的6个TC降水进行了客观分离,并与人工的主观识别方法进行了对比.结果表明,OSAT客观方法由于对TC外围流系最大范围半径D1设置偏大,导致原来的判别测站数比主观方法多,其他系统或TC和其他系统共同作用的降水被包含进来,所以误判率较高,但遗漏少.为了减少误判率,将OSAT方法中的D1根据实况环流场给出,判别准确率得到了提高,但会出现判别结果比主观方法略偏少的现象,原因是TC和其它系统(冷锋、西风槽等)的相互作用结果没有考虑进去.总的来说,对D1的设定由原来根据TC强弱度给出常参数方案组改为根据实况观测、云图等资料获得后,提高了识别效果.使用该客观方法识别TC降水的精确度能满足业务需求,可以投入业务使用. 相似文献
16.
The Dynamical-Statistical-Analog Ensemble Forecast model for landfalling tropical cyclones (TCs) precipitation (DSAEF_LTP) utilises an operational numerical weather prediction (NWP) model for the forecast track, while the precipitation forecast is obtained by finding analog cyclones, and making a precipitation forecast from an ensemble of the analogs. This study addresses TCs that occurred from 2004 to 2019 in Southeast China with 47 TCs as training samples and 18 TCs for independent forecast experiments. Experiments use four model versions. The control experiment DSAEF_LTP_1 includes three factors including TC track, landfall season, and TC intensity to determine analogs. Versions DSAEF_LTP_2, DSAEF_LTP_3, and DSAEF_LTP_4 respectively integrate improved similarity region, improved ensemble method, and improvements in both parameters. Results show that the DSAEF_LTP model with new values of similarity region and ensemble method (DSAEF_LTP_4) performs best in the simulation experiment, while the DSAEF_LTP model with new values only of ensemble method (DSAEF_LTP_3) performs best in the forecast experiment. The reason for the difference between simulation (training sample) and forecast (independent sample) may be that the proportion of TC with typical tracks (southeast to northwest movement or landfall over Southeast China) has changed significantly between samples. Forecast performance is compared with that of three global dynamical models (ECMWF, GRAPES, and GFS) and a regional dynamical model (SMS-WARMS). The DSAEF_LTP model performs better than the dynamical models and tends to produce more false alarms in accumulated forecast precipitation above 250 mm and 100 mm. Compared with TCs without heavy precipitation or typical tracks, TCs with these characteristics are better forecasted by the DSAEF_LTP model. 相似文献
17.
登陆热带气旋在鄱阳湖区的活动特征及原因分析 总被引：2，自引：0，他引：2
鄱阳湖流域是受登陆热带气旋（简称TC）影响最为频繁的内陆地区之一。利用中国气象局热带气旋年鉴资料、地面观测资料、中国气象局一日两次的常规探空资料以及NCEP/NCAR一日四次的2.5°×2.5°再分析资料,研究了过鄱阳湖TC的活动特征及其影响。首先统计1949~2012年进入鄱阳湖区域61个TC的活动特征发现,平均而言进入鄱阳湖地区的TC具有移速减慢,强度衰减变缓及降水增幅特征。大尺度环流场分析表明,登陆进入鄱阳湖区的TC处于太平洋副热带高压和东亚大陆高压之间的鞍形场中,引导气流减弱,水平风垂直切变减小,有利于其移速减慢、衰减减缓以及降水累计。几个典型TC个例的观测分析发现,TC降水降低了鄱阳湖区浅层土壤温度和低层大气温度及其日较差,但增加了土壤和空气湿度。鄱阳湖区域下垫面较高的地面热量有利于TC维持。而湖区对流有效位能在TC进入后明显降低,说明TC触发了该区域对流有效位能释放,有利于其降水增幅。 相似文献
18.
利用常规观测资料、中国气象局上海台风研究所(CMA-STI)热带气旋最佳路径数据和FY-2C卫星云图观测资料,以0608台风派比安和0809强热带风暴北冕两个西行热带气旋影响云南降水为例,通过其路径、降水量、移动速度、环境场和物理量场的对比分析,结果表明:两次台风源地、移动路径及登陆地点、影响时段、最大降水落区相同,但影响时间长度、影响范围和造成的灾害程度后者强于前者;西南季风与热带辐合带(ITCZ)较活跃,副热带高压西伸增强,并有低空急流、辐合区配合台风低压环流共同作用是热带气旋导致云南强降水的重要天气背景;云图中尺度分析发现,多种系统的共同作用,导致台风环流持久不消,进而易激发多个α-中尺度对流系统(MαCS)和β-中尺度对流系统(MβCS)云团生成并持久维持,是台风低压强降水发生的直接原因;物理量场的诊断分析表明,活跃的季风系统,使孟加拉湾和南海构成强大的水汽通道,伴随低空急流的建立和增强,致使大量不稳定能量和水汽向云南输送,在云南形成条件性对称不稳定(CSI)和深厚斜压性的正反馈机制,是导致云南强降水的重要物理机制。 相似文献
19.
The interdecadal variations of tropical cyclones(TCs) and their precipitation over Guangdong Province are investigated using the observational data of TCs and precipitation from 26 observational stations in the province from 1951 to 2005.The results show that the TCs precipitation shows an oscillation with a peak value of about 25 years,with both the numbers of the Guangdong-influencing TCs and TCs formed in the western North Pacific oscillating with a peak value of about 23 years.The correlations are highly positive between the interdecadal variation of TC precipitation over the province and these numbers.The interdecadal variation of TC precipitation in the province shows significant negative correlations with the interdecadal variation of annual mean SST in some parts of the western North Pacific and the interdecadal variation of annual mean 500 hPa geopotential heights in some parts of the middle and high latitudes over the North Pacific.In general,there are high mean SSTs on the equator from central to eastern Pacific,low mean SSTs in the middle and high latitudes over the North Pacific and a main strong East Asian trough over the North Pacific in the period of less TC precipitation as compared with the period of more TC precipitation over the province. 相似文献
20.
In this paper, 1416 conventional ground-based meteorological
observation stations on the mainland of China were subdivided into
groups of differing spatial density. Data from each subgroup were then
used to analyze variations in the tropical cyclone (TC) precipitation
statistics derived from each subgroup across the mainland of China
(excluding Taiwan, Hong Kong, and Macao), as well as in two regions
(east China and south China) and three provinces (Guangdong, Hainan,
and Jiangxi) between 1981 and 2010. The results showed that for the
mainland of China, total precipitation, mean annual precipitation, mean
daily precipitation, and its spatial distribution were the same
regardless of the spatial density of the stations. However, some minor
differences were evident with respect to precipitation extremes and
their spatial distribution. Overall, there were no significant
variations in the TC precipitation statistics calculated from different
station density schemes for the mainland of China. The regional and
provincial results showed no significant differences in mean daily
precipitation, but this was not the case for the maximum daily
precipitation and torrential rain frequency. The maximum daily
precipitation calculated from the lower-density station data was
slightly less than that based on the higher-density station schemes,
and this effect should be taken into consideration when interpreting
regional climate statistics. The impact of station density on TC
precipitation characteristics was more obvious for Hainan than for
Guangdong or Jiangxi provinces. In addition, the effects were greater
for south China (including Guangxi Zhuang Autonomous region, Guangdong,
and Hainan provinces) than east China (including Shandong, Jiangsu,
Zhejiang, Shanghai, Fujian, Anhui, and Jiangxi provinces). Furthermore,
the analysis proved that the statistical climatic characteristics began
to change significantly when the station spacing was between 40 and 50
km, which are close to the mean spacing for all stations across the
mainland of China. Moreover, TC areal precipitation parameters,
including mean total areal precipitation and mean daily areal
precipitation, also began to change significantly when the spacing was
between 40 and 50 km, and were completely different when it was between
100 and 200 km. 相似文献