Spatial distribution of tropical cyclone rainfall and its contribution to the climatology of Puerto Rico     

José J. Hernández Ayala  Corene J. Matyas 《自然地理学》2018,39(1):1-20

This study explores two different tropical cyclone rainfall (TCR) problems: first, the identification of areas where TCR is highly concentrated and, second, the contribution of tropical cyclones (TCs) to the climatology of Puerto Rico for the period 1970–2010. A total of 86 storms within a 500-km radius of Puerto Rico were analyzed. Daily and monthly rainfall data from 32 weather stations were used to generate interpolated surfaces. Two geostatistical interpolation techniques were implemented: ordinary kriging and ordinary cokriging. Results show that rainfall from most TCs tends to be clustered in the eastern, southeastern, and central regions of the island, with a decrease in values toward the west. TCs closer to Puerto Rico (≤230 km) and embedded in high moisture environments (≥44.5 mm) exhibited the highest rainfall values, with most concentrated in the high elevation areas of the southeastern region of the island. Months with the largest TC contributions to rainfall (20–30%) were August and September, while the lowest contributions were found in June and November. For August, stations in the southern and eastern portions of the island had TCR contributions of >20%, with some stations in the southern coastal plains exhibiting 30%.  相似文献   

THE EFFECT OF WARM POOL THERMAL STATES ON TROPICAL CYCLONES IN THE WESTERN NORTH PACIFIC     

陈光华  黄荣辉 《热带气象学报(英文版)》2007,13(1):53-56

The influence of thermal states in the warm pool on tropical cyclones (TCs) in the western North Pacific (WNP) is investigated. There are fewer typhoons during warm years of the warm pool in which tropical storms tend to form in the northwest quadrant and move westward. Inversely, typhoons tend to recurve northeastward to the southeast of Japan and increase in number in the southeast quadrant during cold years. Based on composite analyses, circulation-induced dynamic factors rather than thermal factors are identified as being responsible for TCs activities. During the warm state, the monsoon trough retreats westwards, which leads to anomalous vorticity in low-level and divergence in high-level in the western part of west Pacific. Above-normal TCs activity is found in this area. Furthermore, wind anomalies at 500 hPa determine the main track types. On the contrary, when the warm pool is in cold state, the atmospheric circulation is responsible for the formation of more TCs in the southeast quadrant and recurving track.  相似文献   

Large-scale Vertical Momentum,Kinetic Energy and Moisture Fluxes in the Antarctic Sea-ice Region     

Ian?SimmondsEmail author  Anthony?Rafter  Timothy?Cowan  Andrew?B.?Watkins  Kevin?Keay 《Boundary-Layer Meteorology》2005,117(1):149-177

There are very strong thermal gradients between the Antarctic continent and the sea-ice zone, and between that zone and the ocean to the north. As a result of these contrasts the sea-ice domain is one of strong cyclogenesis and high cyclone frequency. In this study we explore many aspects of that cyclonic behaviour and investigate the manner in which these systems influence, and are influenced by, the sea ice. Using the NCEP-DOE re-analyses (1979–2002) we have determined variables that are proportional to the mean of the wind stress and the mean rate at which mechanical energy is imparted to the surface. Using two decompositions of the wind field we have obtained estimates of how much of these fluxes are contributed to by the transient eddies. We find these to be significant over the sea ice and the ocean to the north, particularly when a new decomposition is used. The presence of frequent and vigorous cyclones is a central factor that determines the positive mean freshwater flux over the sea-ice zone in all seasons. This transfer to the ocean is smallest in summer (0.49 mm day⁻¹) and assumes a maximum of 1.27 mm day⁻¹ in winter.  相似文献   

A FUZZY MATHEMATICS EVALUATION OF THE DISASTER BY TROPICAL CYCLONES     

梁必骐  樊琦  杨洁  王同美 《热带气象学报(英文版)》2000,6(1):94-99

In this paper, data from disaster reduction in China have been used to statistically analy ze the disaster by tropical cyclones that occurred from 1979 to 1996 within the area of Guangdong province. By the method of fuzzy subset theory, the conditions of the disaster have been discussed and the evaluation model of the disaster B set up. The index of the disaster of every tropical cyclone have been obtained and divided into five parts. The result shows that the index is almost proportional to the direct economic losses, so this model is reasonable.  相似文献   

赤道东太平洋海温对东亚～西北太平洋温带气旋的影响   总被引：1，自引：0，他引：1  

林玉英  战淑芸 《海洋预报》2000,17(2):16-24

本文分析了东亚～西北太平洋较强温带气旋的气修特征及其与赤道东太平洋海温的关系。得出,厄尔尼诺年或厄尔尼诺持续年,较强温带气旋偏多的对应关系占找优势。但当副热带高压偏强时,则较强温带气旋偏少。  相似文献   

An Isentropic Mass Circulation View on the Extreme Cold Events in the 2020/21 Winter     

Yueyue YU  Yafei LI  Rongcai REN  Ming CAI  Zhaoyong GUAN  Wei HUANG 《大气科学进展》2022,39(4):643-657

Three extreme cold events successively occurred across East Asia and North America in the 2020/21 winter.This study investigates the underlying mechanisms of these record-breaking persistent cold events from the isentropic mass circulation(IMC)perspective.Results show that the midlatitude cold surface temperature anomalies always co-occurred with the high-latitude warm anomalies,and this was closely related to the strengthening of the low-level equatorward cold air branch of the IMC,particularly along the climatological cold air routes over East Asia and North America.Specifically,the two cold surges over East Asia in early winter were results of intensification of cold air transport there,influenced by the Arctic sea ice loss in autumn.The weakened cold air transport over North America associated with warmer northeastern Pacific sea surface temperatures(SSTs)explained the concurrent anomalous warmth there.This enhanced a wavenumber-1 pattern and upward wave propagation,inducing a simultaneous and long-lasting stronger poleward warm air branch(WB)of the IMC in the stratosphere and hence a displacement-type Stratospheric Sudden Warming(SSW)event on 4 January.The WB-induced increase in the air mass transported into the polar stratosphere was followed by intensification of the equatorward cold branch,hence promoting the occurrence of two extreme cold events respectively over East Asia in the beginning of January and over North America in February.Results do not yield a robust direct linkage from La Ni?a to the SSW event,IMC changes,and cold events,though the extratropical warm SSTs are found to contribute to the February cold surge in North America.  相似文献   

Response based design metocean conditions for a permanently moored FPSO during tropical cyclones: Estimation of greenwater risk     

《Applied Ocean Research》2019

Response based analysis (RBA) is used to establish the design metocean conditions (DMCs) of a generic weather-vaning FPSO off the North West Shelf (NWS) of Australia for determining greenwater severity. A vessel heading prediction tool, an essential component of the RBA analysis for weather-vaning vessels, is developed and evaluated by comparing with full-scale measurements from an operating FPSO. Locations at the bow, amidships and the stern of the vessel are found to be susceptible to greenwater risks and the vessel is often exposed to oblique waves during tropical cyclones. Long-term extrapolation is performed to estimate 1 in. N-year return relative wave-vessel motions represented by both the most probable maximum relative wave-vessel motion within a storm r_mp, and the maximum individual relative wave-vessel motion r_Max. It is observed that r_Max ˜ (1.1–1.2) r_mp. The use of r_Max allows for the variability of the short term maxima per storm and also the fact that the peak in response might not come in the most severe sea-state. Given the focus on greenwater rather than wave severity, the slightly larger value of r_Max at a given return period is used for assessment of greenwater risk. The sea-states that lead to r_Max at a 1 in 100 year level are identified and subsequently used for characterising the wave groups causing maximum relative wave-vessel motion at various locations around the vessel. For a given location, the shapes of the wave time histories which give rise to extreme relative wave-vessel motions in a set of design metocean conditions are similar, indicating that a ‘design wave’, derived within the framework of linear wave theory, may be a useful approach to tackle highly nonlinear and complex greenwater overtopping problems.  相似文献   

影响中国及关键经济区热带气旋降水的气候趋势及极端性特征   总被引：3，自引：0，他引：3  

巢清尘  巢纪平 《大气科学》2014,38(6):1029-1040

本文利用中国气象局上海台风研究所整编的《热带气旋年鉴》(1951~2010年)最佳路径资料,分析影响我国和关键经济区热带气旋(TC)降水量、降水强度以及不同等级降水TC频数的气候变化趋势,研究结果表明,影响全国的TC总降水量的年际变化幅度大,年际差异显著。长江三角洲、珠江三角洲地区影响TC过程雨量年极值自1970年代开始缓慢上升,表明近年来TC引起的极端性降水存在增加的可能。全国范围内自1970年代开始,过程雨量大于250 mm的TC频数也在增加,但长江三角洲、珠江三角洲地区发生极端性降水的TC频数并没有明显的增长。TC造成的24小时降水极值的气候变化趋势不明显,但是1980年代全国范围内的24小时降水极值存在跃变。长江三角洲、珠江三角洲地区日降水极值超过250 mm的TC频数自1980年代开始有缓慢增加趋势。全国范围、长江三角洲及珠江三角洲内TC小时降雨量年极值呈现振荡的周期变化,而在年代际上没有明显的变化趋势。  相似文献   

云浮高温天气及其环流形势统计与分析     

莫贤清  钟珑  谭成坤 《广东气象》2014,(3):30-36

为加深对云浮高温天气特征的认识,对云浮地区1981—2010年高温天气及其与副高、热带气旋之间关系进行统计分析。结果表明:云浮地区年高温天气大体呈增加趋势,测站局地环境不一致导致各测站高温天气年变化的并不一致。云浮地区高温天气主要出现在6—8月,7月最多,8月次之。云浮地区高温环流形势可分为4类:副高型、台风Ⅰ型、台风Ⅱ型和其它型。500 hPa位势高度(台风强度)与云浮地区台风I型(台风Ⅱ型)高温的关系不明显。500 hPa位势高度较高有利于台风Ⅱ型、副高型、其它型高温的发生发展。500 hPa位势高度大值中心位于测站以北(以西)有利于台风II型(其它型)高温发生发展,位于测站以东时副高型高温较多,位于测站东南则不利于高温天气发生发展。台风中心位于测站东北、东、东南三个方位,台风中心与测站距离600~1 600 km,台风强度在TS及以上时,有利于台风I型高温的发生发展。台风中心位于测站东方方位,台风中心与测站距离1 600~2 200 km,有利于台风Ⅱ型高温的发生发展。  相似文献   

A global climatology of extreme rainfall rates in the inner core of intense tropical cyclones     

Ian Chang  Mace L. Bentley  J. Marshall Shepherd 《自然地理学》2014,35(6):478-496

The localized rain rate maxima (R_M) of the inner core region of intense tropical cyclones (TCs) are investigated using Version 6 of the Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis data-set from 1998 to 2010. Specifically, this study examines the probabilities of R_M exceeding 25 mm h^?1 (P25) in intense TCs. The 25 mm h^?1 R_M is the 90th percentile of all R_M observations during the study period. The descending order of P25 observed from intense TCs for the six major ocean basins is: the North Indian Ocean, the Atlantic Ocean, the Northwest Pacific Ocean, the South Pacific Ocean, the South Indian Ocean, and the East-central Pacific Ocean. The six major basins have been subdivided into 29 sub-basins to discern regional variability of R_M. P25 increases with increasing TC category in all major basins, except for the South Pacific. Sub-basins with intense TCs that produce extreme rainfall rate maxima include the Bay of Bengal, the South Philippine Sea, the East China Sea, the north coast of Australia, southeast Melanesia, and the Northwest Atlantic. Sub-basins with a higher proportion of category 5 (CAT5) observations than category 3 (CAT3) observations tend to have a greater P25 beyond 60 km from the storm center.  相似文献