Mangroves play a pivotal role in tropical and subtropical coastal ecosystem,yet they are highly vulnerable to the effects of climate change,particularly the accelerated global sea level rise(SLR)and stronger tropical ...Mangroves play a pivotal role in tropical and subtropical coastal ecosystem,yet they are highly vulnerable to the effects of climate change,particularly the accelerated global sea level rise(SLR)and stronger tropical cyclones(TCs).However,there is a lack of research addressing future simultaneous combined impacts of the slow-onset of SLR and rapid-onset of TCs on China's mangroves.In order to develop a comprehensive risk assessment method considering the superimposed effects of these two factors and analyze risk for mangroves in Dongzhaigang,Hainan Island,China,we used observational and climate model data to assess the risks to mangroves under low,intermediate,and very high greenhouse gas(GHG)emission scenarios(such as SSP1-2.6,SSP2-4.5,and SSP5-8.5)in 2030,2050,and 2100,and compiled a risk assessment scheme for mangroves in Dongzhaigang,China.The results showed that the combined risks from SLR and TCs will continue to rise;however,SLRs will increase in intensity,and TCs will decrease.The comprehensive risk of the Dongzhaigang mangroves posed by climate change will remain low under SSP1-2.6 and SSP2-4.5 scenarios by 2030,but it will increase substantially by 2100.While under SSP5-8.5 scenario,the risks to mangroves in Dongzhaigang are projected to increase considerably by 2050,and approximately 68.8%of mangroves will be at very high risk by 2100.The risk to the Dongzhaigang mangroves is not only influenced by the hazards but also closely linked to their exposure and vulnerability.We therefore propose climate resilience developmental responses for mangroves to address the effects of climate change.This study for the combined impact of TCs and SLR on mangroves in Dongzhaigang,China can enrich the method system of mangrove risk assessment and provide references for scientific management.展开更多
The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casual...The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casualties in the coastal region every year. By counting and analyzing the tropical cyclones affecting Guangxi coast from 1950 to 2012, we find that the annual number of tropical cyclones changes significantly, and the maximum value can be up to 9, whereas the minimum value is 0 in some year. The regularity of seasonal distribution of tropical cyclones is obvious, and the peak period is in July, August and September every year, followed by June and October. Most of tropical cyclones come from the east of Philippines. After entering the South China Sea and passing through Hainan province and Leizhou Peninsula, they landed on Guangxi coast once again and caused the mean of peak surge reaching 111.2 cm, which is 2.6 times of non-landing typhoon. The formation of storm surge disaster is directly related to the severe typhoon weather systems, diurnal spring tide and discharge of river flood. Severe typhoons generate huge waves and rainfall, which lead to the rise of water level at the estuary, and would result in significant increasing water when stacking up with the storm surge, and cause huge tidal disaster.展开更多
Using the Joint Typhoon Warning Center (JTWC) and China Meteorological Administration (CMA) tropical cyclone track datasets, variations in frequency and intensity of the affecting-China tropical cyclones (ACTCs)...Using the Joint Typhoon Warning Center (JTWC) and China Meteorological Administration (CMA) tropical cyclone track datasets, variations in frequency and intensity of the affecting-China tropical cyclones (ACTCs) are studied for the period of 1965-2004. First, the differences between the two tropical cyclone datasets are examined. The annual frequencies of tropical cyclones in the western North Pacific basin are reasonably consistent to each other, while the intensity records are less reliable. The annual numbers of ACTCs based on different datasets are close to each other with similar interdecadal and interannual variations. However, the maximum intensity and the annual frequency of ACTCs for strong categories show great dependence on datasets. Tropical cyclone impacts on China show the same variations as the annual number of ACTCs and also show dependence on datasets. Differences in tropical cyclone impacts on China are mainly caused by datasets used. The annual frequency of ACTCs, especially the length of lifetime of ones that make landfall, and the intensity estimates all have effects on the value of impacts on China.展开更多
In this study, tropical cyclone data from China Meteorological Administration (CMA) and the ECMWF reanalysis data for the period 1958-2001 was used to propose a possible mechanism for the impacts of air- sea interac...In this study, tropical cyclone data from China Meteorological Administration (CMA) and the ECMWF reanalysis data for the period 1958-2001 was used to propose a possible mechanism for the impacts of air- sea interaction on the activity of tropical cyclones (TCs) affecting China. The frequency of TCs affecting China over past 40 years has trended downward, while during the same period, the air sea interaction in the two key areas of the Pacific region has significantly weakened. Our diagnoses and simulations suggest that air sea interactions in the central North Pacific tropics and subtropics (Area 1) have an important role in adjusting typhoon activities in the Northwest Pacific in general, and especially in TC activity affecting China. On the contrary, impacts of the air-sea interaction in the eastern part of the South Pacific tropics (Area 2) were found to be rather limited. As both observational analysis and modeling studies show that, in the past four decades and beyond, the weakening trend of the latent heat released from Area 1 matched well with the decreasing Northwest Pacific TC frequency derived from CMA datasets. Results also showed that the weakening trend of latent heat flux in the area was most likely due to the decreasing TC frequency over the Northwest Pacific, including those affecting China. Although our preliminary analysis revealed a possible mechanism through which the air sea interaction may adjust the genesis conditions for TCs, which eventually affect China, other relevant questions, such as how TC tracks and impacts are affected by these trends, remain unanswered. Further in-depth investigations are required.展开更多
This study investigated the impact of sea surface temperature(SST)in several important areas of the Indian-Pacific basin on tropical cyclone(TC)activity over the western North Pacific(WNP)during the developing years o...This study investigated the impact of sea surface temperature(SST)in several important areas of the Indian-Pacific basin on tropical cyclone(TC)activity over the western North Pacific(WNP)during the developing years of three super El Ni?o events(1982,1997,and 2015)based on observations and numerical simulations.During the super El Ni?o years,TC intensity was enhanced considerably,TC days increased,TC tracks mostly recurved along the coasts,and fewer TCs made landfall in China.These characteristics are similar to the strong ENSO-TC relationship but further above the climatological means than in strong El Ni?o years.It indicates that super El Ni?o events play a dominant role in the intensities and tracks of WNP TCs.However,there were clear differences in both numbers and positions of TC genesis among the different super El Ni?o years.These features could be attributed to the collective impact of SST anomalies(SSTAs)in the tropical central-eastern Pacific and East Indian Ocean(EIO)and the SST gradient(SSTG)between the southwestern Pacific and the western Pacific warm pool.During 2015,the EIO SSTA was extremely warm and the anomalous anticyclone in the western WNP was enhanced,resulting in fewer TCs than normal.In 1982,the EIO SSTA and spring SSTG showed negative anomalies,followed by an increased anomalous cyclone in the western WNP and equatorial vertical wind shear.This intensified the conversion of eddy kinetic energy from large-scale flows,favorable for the westward shift of TC genesis.Consequently,anomalous TC activities during the super El Ni?o years resulted mainly from combined SSTA impacts of different key areas over the Indian-Pacific basin.展开更多
Tropical cyclones (TCs) and storms (TSs) are among the devastating events in the world and southwestern Indian Ocean (SWIO) in particular. The seasonal forecasting TCs and TSs for December to March (DJFM) and November...Tropical cyclones (TCs) and storms (TSs) are among the devastating events in the world and southwestern Indian Ocean (SWIO) in particular. The seasonal forecasting TCs and TSs for December to March (DJFM) and November to May (NM) over SWIO were conducted. Dynamic parameters including vertical wind shear, mean zonal steering wind and vorticity at 850 mb were derived from NOAA (NCEP-NCAR) reanalysis 1 wind fields. Thermodynamic parameters including monthly and daily mean Sea Surface Temperature (SST), Outgoing Longwave Radiation (OLR) and equatorial Standard Oscillation Index (SOI) were used. Three types of Poison regression models (i.e. dynamic, thermodynamic and combined models) were developed and validated using the Leave One Out Cross Validation (LOOCV). Moreover, 2 × 2 square matrix contingency tables for model verification were used. The results revealed that, the observed and cross validated DJFM and NM TCs and TSs strongly correlated with each other (p ≤ 0.02) for all model types, with correlations (r) ranging from 0.62 - 0.86 for TCs and 0.52 - 0.87 for TSs, indicating great association between these variables. Assessment of the model skill for all model types of DJFM and NM TCs and TSs frequency revealed high skill scores ranging from 38% - 70% for TCs and 26% - 72% for TSs frequency, respectively. Moreover, results indicated that the dynamic and combined models had higher skill scores than the thermodynamic models. The DJFM and NM selected predictors explained the TCs and TSs variability by the range of 0.45 - 0.65 and 0.37 - 0.66, respectively. However, verification analysis revealed that all models were adequate for predicting the seasonal TCs and TSs, with high bias values ranging from 0.85 - 0.94. Conclusively, the study calls for more studies in TCs and TSs frequency and strengths for enhancing the performance of the March to May (MAM) and December to October (OND) seasonal rainfalls in the East African (EA) and Tanzania in particular.展开更多
The study investigated the influence of Tropical cyclone (TCs) to the plant productivity indices along the coast of Tanzania using both field observations and change detection methods. These indices are normally desig...The study investigated the influence of Tropical cyclone (TCs) to the plant productivity indices along the coast of Tanzania using both field observations and change detection methods. These indices are normally designed to maximize the sensitivity of the vegetation characteristics and are very crucial in monitoring droughts intensity, yield and biomass amongst others. The study used three types of satellite imageries including the 16 days Moderate Resolution Imaging Spectroradiometer (MODIS) of 250 <span><span><span style="font-family:;" "="">×<span> 250 m resolution;8 days Landsat 7 enhanced thematic mapper (ETM) with resolution of 30 </span>×<span> 30 m composites, and 5 Landsat 8 (LC8) images, to determine the patterns and the variability of the Normalized Difference Vegetation Index (NDVI) and En<span>hanced Vegetation Index (EVI) and TCs impacts on vegetation. Moreover, we</span> <span>used Tropical Rainfall Measuring Mission (TRMM) data and the daily to</span> monthly rainfall data from Tanzanian Meteorological Authority (TMA). The change detection between the pre and post storm (TCs) conditions was used to analyse inter annual variability of EVI over Chwaka, Rufiji and Pugu— Kazimzumbwi. The changes in NDVI and EVI and monthly rainfall at the coastal stations were calculated, plotted and analyzed. The results revealed that, highest EVI values over coastal Tanzania were observed during March <span>and April, and minimum (low) values in November. The results for EV</span>I changes based on pre and post storm conditions revealed that most observed stations and most TCs led to significant EVI changes which ranged from </span>-<span>0.05 to 0.19, and </span>-<span>0.3 to 0.22, for MODIS and L7 ETM data, respectively. As for the spatial changes in NDVI results revealed that, TCs (Besija and Fob<span>ane) </span><span>were associated with positive NDVI changes <i>i.e.</i> (enhancement) of >0.51 </span><span>an</span>d >0.31, and NDVI reduction (<i>i.e.</i> negative changes) of <0.02 and <</span>-<span>0.19 <span>for Chwaka and Rufiji, respectively. Besides the results revealed that, TCs episodes have induced a land cover changes from <i>i.e.</i> water covered areas</span> changed to be vegetation covered especially over the shorelines and inter tidal areas. Indeed, these results were consistent with the analysis of rainfall patterns which indicated that low rainfall occurred in low NDVI areas and vice versa.</span></span></span></span>展开更多
Tropical cyclones constitute a major risk for coastal communities.To assess their damage potential,accurate predictions of their intensification are needed,which requires a detailed understanding of the evolution of t...Tropical cyclones constitute a major risk for coastal communities.To assess their damage potential,accurate predictions of their intensification are needed,which requires a detailed understanding of the evolution of turbulent heat flux(THF).By combining multiple buoy observations along the south north storm track,we investigated the THF anomalies associated with tropical storm Danas(2019)in the East China Sea(ECS)during its complete life cycle from the intensification stage to the mature stage and finally to its dissipation on land.The storm passage is characterized by strong winds of 10-20 m/s and a sea level pressure below 1000 hPa,resulting in a substantial enhancement of THF.Latent heat(LH)fluxes are most strongly affected by wind speed,with a gradually increasing contribution of humidity along the trajectory.The relative contributions of wind speed and temperature anomalies to sensible heat(SH)depend on the stability of the boundary layer.Under stable conditions,SH variations are driven by wind speed,while under near-neutral conditions,SH variations are driven by temperature.A comparison of the observed THF and associated variables with outputs from the ERA 5 and MERRA 2 reanalysis products reveals that the reanalysis products can reproduce the basic evolution and composition of the observed THF.However,under extreme weather conditions,temperature and humidity variations are poorly captured by ERA 5 and MERRA 2,leading to large LH and SH errors.The differences in the observed and reproduced LH and SH during the passage of Danas amount to 26.1 and 6.6 W/m^(2) for ERA 5,respectively,and to 39.4 and 12.5 W/m^(2) for MERRA 2,respectively.These results demonstrate the need to improve the representation of tropical cyclones in reanalysis products to better predict their intensification process and reduce their damage.展开更多
Tropical cyclone (TC) Nargis (2008) made landfall in Myanmar on 02 May 2008, bringing a storm surge, major flooding, and resulting in a significant death toll. TC Nargis (2008) displayed abnormal features, inclu...Tropical cyclone (TC) Nargis (2008) made landfall in Myanmar on 02 May 2008, bringing a storm surge, major flooding, and resulting in a significant death toll. TC Nargis (2008) displayed abnormal features, including rare eastward motion in its late stage, rapid intensification before landing. Using reanalysis data and a numerical model, we investigated how a low-latitude westerly wind modulated TC Nargis’ (2008) track and provided favorable atmospheric conditions for its rapid intensification. More importantly, we found a possible counterbalance effect of flows from the two hemispheres on the TC track in the Bay of Bengal. Our analysis indicates that a strong westerly wind burst across the Bay of Bengal, resulting in TC Nargis’ (2008) eastward movement after its recurvature. This sudden enhancement of westerly wind was mainly due to the rapidly intensified mid-level cross-equatorial flow. Our results show that a high-pressure system in the Southern Hemisphere induced this strong, mid-level, cross-equatorial flow. During the rapid intensification period of TC Nargis (2008), this strong and broad westerly wind also transported a large amount of water vapor to TC Nargis (2008). Sufficient water vapor gave rise to continuously high and increased mid-level relative humidity, which was favorable to TC Nargis’ (2008) intensification. Condensation of water vapor increased the energy supply, which eventuated the intensification of TC Nargis (2008) to a category 4 on the Saffir-Simpson scale.展开更多
Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses...Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses to local warm sea surface temperatures and feedbacks,with aid from coherent coupled initialization.This study uses three sets of highresolution regional coupled models(RCMs)covering the Asia−Pacific(AP)region initialized with local observations and dynamically downscaled coupled data assimilation to evaluate the predictability of TC genesis in the West Pacific.The APRCMs consist of three sets of high-resolution configurations of the Weather Research and Forecasting−Regional Ocean Model System(WRF-ROMS):27-km WRF with 9-km ROMS,and 9-km WRF with 3-km ROMS.In this study,a 9-km WRF with 9-km ROMS coupled model system is also used in a case test for the predictability of TC genesis.Since the local sea surface temperatures and wind shear conditions that favor TC formation are better resolved,the enhanced-resolution coupled model tends to improve the predictability of TC genesis,which could be further improved by improving planetary boundary layer physics,thus resolving better air−sea and air−land interactions.展开更多
The scale, shape and position are three main factors to forecast tropical cyclone. The aim of the paper is to recognize tropical cyclone (TC) in the satellite cloud pictures according to the scale, shape and positio...The scale, shape and position are three main factors to forecast tropical cyclone. The aim of the paper is to recognize tropical cyclone (TC) in the satellite cloud pictures according to the scale, shape and position of clouds. The study includes Canny edge detection, contour extraction and other techniques. The solutions are also established. The experiments show that the method can recognize the TC in the satellite pictures. The study is beneficial for TC track.展开更多
The present study investigates modulation of western North Pacific (WNP) tropical cyclone (TC) genesis in relation to different phases of the intraseasonal oscillation (ISO) of ITCZ convection during May to Octo...The present study investigates modulation of western North Pacific (WNP) tropical cyclone (TC) genesis in relation to different phases of the intraseasonal oscillation (ISO) of ITCZ convection during May to October in the period 1979 2008. The phases of the ITCZ ISO were determined based on 30-80-day filtered OLR anomalies averaged over the region (5°20′N, 120°150′E). The number of TCs during the active phases was nearly three times more than during the inactive phases. The active (inactive) phases of ISO were characterized by low-level cyclonic (anticyclonic) circulation anomalies, higher (lower) midlevel relative humidity anomalies, and larger (smaller) vertical gradient anomalies of relative vorticity associated with enhanced (weakened) ITCZ convection anomalies. During the active phases, TCs tended to form in the center of the ITCZ region. Barotropic conversion from the low-level mean flow is suggested to be the major energy source for TC formation. The energy conversion mainly depended on the zonal and meridional gradients of the zonal flow during the active phases. However, barotropic conversion weakened greatly during the inactive phases. The relationship between the meridional gradient of absolute vorticity and low-level zonal flow indicates that the sign of the absolute vorticity gradient tends to be reversed during the two phases, whereas the same sign between zonal flow and the absolute vortieity gradient is more easily satisfied in the active phases. Thus, the barotropie instability of low-level zonal flow might be an important mechanism for TC formation over the WNP during the active phases of ISO.展开更多
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 cyclon...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.展开更多
Based on analyzing the surface air temperature series in the Southern and Northern Hemisphere and the tropical cyclone (TC) over the western North Pacific Ocean, the relationships between climatic warming and the freq...Based on analyzing the surface air temperature series in the Southern and Northern Hemisphere and the tropical cyclone (TC) over the western North Pacific Ocean, the relationships between climatic warming and the frequency and intensity of tropical cyclone are investigated. The results showed that with the climatic warming in both hemispheres, the frequency of the tropical cyclone over the western North Pacific Ocean reduces and its intensity weakens simultaneously. A possible explanation might be that the cold air invasion from the Southern Hemisphere weakens due to global warming.展开更多
The effects of vertical wind shear on tropical cyclone(TC) intensity change are examined based on the TC data from the China Meteorological Administration and the NCEP reanalysis daily data from 2001 to 2006.First,the...The effects of vertical wind shear on tropical cyclone(TC) intensity change are examined based on the TC data from the China Meteorological Administration and the NCEP reanalysis daily data from 2001 to 2006.First,the influence of wind shear between different vertical levels and averages in different horizontal areas are compared.The results indicate that the effect of wind shear between 200 and 850 hPa averaged within a 200-800 km annulus on TC intensity change is larger than any other calculated vertical wind shear.High-latitude and intense TCs tend to be less sensitive to the effects of VWS than low-latitude and weak TCs.TCs experience time lags between the imposition of the shear and the weakening in TC intensity.A vertical shear of 8-9 m/s(9-10 m/s) would weaken TC intensity within 60 h(48 h).A vertical shear greater than 10 m/s would weaken TC intensity within 6 h.Finally,a statistical TC intensity prediction scheme is developed by using partial least squares regression,which produces skillful intensity forecasts when potential predictors include factors related to the vertical wind shear.Analysis of the standardized regression coefficients further confirms the obtained statistical results.展开更多
Conventional data and the Yearbook on Tropical Cyclones (TC) data from 1971 to 2000 are used to study the climate and disaster features of TC affecting the Liaodong Peninsula. Results indicate that interannual change ...Conventional data and the Yearbook on Tropical Cyclones (TC) data from 1971 to 2000 are used to study the climate and disaster features of TC affecting the Liaodong Peninsula. Results indicate that interannual change of TC activities is obvious. Different sources of TC have different impacts on the area of interest. Intensity and moving speed of TC vary substantially in the progress of northward movement. Besides, tracks and damage distributions of TC are quite different.展开更多
To understand the impacts of large-scale circulation during the evolution of E1 Nifio cycle on tropical cyclones (TC) is important and useful for TC forecast. Based on best-track data from the Joint Typhoon Warning ...To understand the impacts of large-scale circulation during the evolution of E1 Nifio cycle on tropical cyclones (TC) is important and useful for TC forecast. Based on best-track data from the Joint Typhoon Warning Center and reanalysis data from National Centers for Environmental Prediction for the period 1975- 2014, we investigated the influences of two types of E1 Nifio, the eastern Pacific E1 Nifio (EP-E1 Nifio) and central Pacific E1 Nifio (CP-E1 Nifio), on global TC genesis. We also examined how various environmental factors contribute to these influences using a modified genesis potential index (MGPI). The composites reproduced for two types of E1 Nifio, from their developing to decaying phases, were able to qualitatively replicate observed cyclogenesis in several basins except for the Arabian Sea. Certain factors of MGPI with more influence than others in various regions are identified. Over the western North Pacific, five variables were all important in the two E1Nifio types during developing summer (July-August-September) and fall (October- November-December), and decaying spring (April-May-June) and summer. In the eastern Pacific, vertical shear and relative vorticity are the crucial factors for the two types of El Nifio during developing and decaying summers. In the Atlantic, vertical shear, potential intensity and relative humidity are important for the opposite variation of EP- and CP-EI Nifios during decaying summers. In the Southern Hemisphere, the five variables have varying contributions to TC genesis variation during peak season (January-February-March) for the two types of E1 Nifio. In the Bay of Bengal, relative vorticity, humidity and omega may be responsible for clearly reduced TC genesis during developing fall for the two types and slightly suppressed TC cyclogenesis during EP-E1 Nifio decaying spring. In the Arabian Sea, the EP-E1 Nifio generates a slightly positive anomaly of TC genesis during developing falls and decaying springs, but the MGPI failed to capture this variation.展开更多
An objective technique of tropical cyclone (TC) moving direction prediction over the Northwestern Pacific Ocean during 2001 - 2002 is studied using GMS-50uting-Longwave Radiation (OLR)data. Three formulae used to ...An objective technique of tropical cyclone (TC) moving direction prediction over the Northwestern Pacific Ocean during 2001 - 2002 is studied using GMS-50uting-Longwave Radiation (OLR)data. Three formulae used to predict TC moving direction in 6, 12 and 24 h, respectively, have been obtained based on a multiple linear regression framework and some regression factors including several kinds of OLR characteristic values and the minimum sea level pressure of tropical cyclone center. The multiple correlation coefficients of the statistical analysis using the information of TCs in the Yearbook on Tropical Cyclones to validate the satellite-based prediction are 0.954, 0.945 and 0.914 respectively. The results are satisfying through checking one of the TCs in 2001.The techniques could be applied in future operation and would contribute to TC movement prediction, especially to a sudden change in TC moving direction and improving the forecasting and warning capability.展开更多
Tropical cyclones(TC)pose a persistent natural hazard to Costa Rica.Exposure to natural hazards,such as mass movements and floods,is compounded by a growing urban population and inadequate land use planning.This study...Tropical cyclones(TC)pose a persistent natural hazard to Costa Rica.Exposure to natural hazards,such as mass movements and floods,is compounded by a growing urban population and inadequate land use planning.This study conducted a comprehensive analysis of the economic impacts of TC of Costa Rica from Hurricane Joan in 1988 to Hurricane Eta in 2020,assessing the impact by municipality and economic sector using baseline information of the Ministry of National Planning and Economic Policy.According to the study,road infrastructure(933.8 US million),agriculture(280.5 US million),river rehabilitation(153.96 US million),housing 98.26(US million),and health(81.74 US million)were among the sectors most severely affected by TC over the past 30 years.The Pacific basin municipalities in Costa Rica were found to be the most vulnerable,primarily due to the indirect impacts of TC.The study's results offer useful information on the economic sectors and municipalities that are most exposed from TC in Costa Rica and provide a replicable methodology for other regions and countries facing similar tropical phenomena.展开更多
基金Under the auspices of the National Key Research and Development Program of China (No.2017YFA0604902,2017YFA0604903,2017YFA0604901)。
文摘Mangroves play a pivotal role in tropical and subtropical coastal ecosystem,yet they are highly vulnerable to the effects of climate change,particularly the accelerated global sea level rise(SLR)and stronger tropical cyclones(TCs).However,there is a lack of research addressing future simultaneous combined impacts of the slow-onset of SLR and rapid-onset of TCs on China's mangroves.In order to develop a comprehensive risk assessment method considering the superimposed effects of these two factors and analyze risk for mangroves in Dongzhaigang,Hainan Island,China,we used observational and climate model data to assess the risks to mangroves under low,intermediate,and very high greenhouse gas(GHG)emission scenarios(such as SSP1-2.6,SSP2-4.5,and SSP5-8.5)in 2030,2050,and 2100,and compiled a risk assessment scheme for mangroves in Dongzhaigang,China.The results showed that the combined risks from SLR and TCs will continue to rise;however,SLRs will increase in intensity,and TCs will decrease.The comprehensive risk of the Dongzhaigang mangroves posed by climate change will remain low under SSP1-2.6 and SSP2-4.5 scenarios by 2030,but it will increase substantially by 2100.While under SSP5-8.5 scenario,the risks to mangroves in Dongzhaigang are projected to increase considerably by 2050,and approximately 68.8%of mangroves will be at very high risk by 2100.The risk to the Dongzhaigang mangroves is not only influenced by the hazards but also closely linked to their exposure and vulnerability.We therefore propose climate resilience developmental responses for mangroves to address the effects of climate change.This study for the combined impact of TCs and SLR on mangroves in Dongzhaigang,China can enrich the method system of mangrove risk assessment and provide references for scientific management.
基金supported by National Nature Science (Grant No. 41266002)
文摘The tropical cyclone that lands or passes through Guangxi coast is a serious natural disaster, which brings about strong winds, heavy rains, storm surges and other disasters causing severe damage of property or casualties in the coastal region every year. By counting and analyzing the tropical cyclones affecting Guangxi coast from 1950 to 2012, we find that the annual number of tropical cyclones changes significantly, and the maximum value can be up to 9, whereas the minimum value is 0 in some year. The regularity of seasonal distribution of tropical cyclones is obvious, and the peak period is in July, August and September every year, followed by June and October. Most of tropical cyclones come from the east of Philippines. After entering the South China Sea and passing through Hainan province and Leizhou Peninsula, they landed on Guangxi coast once again and caused the mean of peak surge reaching 111.2 cm, which is 2.6 times of non-landing typhoon. The formation of storm surge disaster is directly related to the severe typhoon weather systems, diurnal spring tide and discharge of river flood. Severe typhoons generate huge waves and rainfall, which lead to the rise of water level at the estuary, and would result in significant increasing water when stacking up with the storm surge, and cause huge tidal disaster.
基金the National Natural Science Foundation of China (Grant No. 40775046) the Chinese Ministry of Science and Technology project (Grant No. 2006CB403601).
文摘Using the Joint Typhoon Warning Center (JTWC) and China Meteorological Administration (CMA) tropical cyclone track datasets, variations in frequency and intensity of the affecting-China tropical cyclones (ACTCs) are studied for the period of 1965-2004. First, the differences between the two tropical cyclone datasets are examined. The annual frequencies of tropical cyclones in the western North Pacific basin are reasonably consistent to each other, while the intensity records are less reliable. The annual numbers of ACTCs based on different datasets are close to each other with similar interdecadal and interannual variations. However, the maximum intensity and the annual frequency of ACTCs for strong categories show great dependence on datasets. Tropical cyclone impacts on China show the same variations as the annual number of ACTCs and also show dependence on datasets. Differences in tropical cyclone impacts on China are mainly caused by datasets used. The annual frequency of ACTCs, especially the length of lifetime of ones that make landfall, and the intensity estimates all have effects on the value of impacts on China.
基金supported by the R&D Special Fund for Public Welfare Industry(meteorology)(Grant No.GYHY200806009)the National Natural Science Foundation of China(GrantNos.40775046,40730106)
文摘In this study, tropical cyclone data from China Meteorological Administration (CMA) and the ECMWF reanalysis data for the period 1958-2001 was used to propose a possible mechanism for the impacts of air- sea interaction on the activity of tropical cyclones (TCs) affecting China. The frequency of TCs affecting China over past 40 years has trended downward, while during the same period, the air sea interaction in the two key areas of the Pacific region has significantly weakened. Our diagnoses and simulations suggest that air sea interactions in the central North Pacific tropics and subtropics (Area 1) have an important role in adjusting typhoon activities in the Northwest Pacific in general, and especially in TC activity affecting China. On the contrary, impacts of the air-sea interaction in the eastern part of the South Pacific tropics (Area 2) were found to be rather limited. As both observational analysis and modeling studies show that, in the past four decades and beyond, the weakening trend of the latent heat released from Area 1 matched well with the decreasing Northwest Pacific TC frequency derived from CMA datasets. Results also showed that the weakening trend of latent heat flux in the area was most likely due to the decreasing TC frequency over the Northwest Pacific, including those affecting China. Although our preliminary analysis revealed a possible mechanism through which the air sea interaction may adjust the genesis conditions for TCs, which eventually affect China, other relevant questions, such as how TC tracks and impacts are affected by these trends, remain unanswered. Further in-depth investigations are required.
基金Supported by the National Basic Research Program of China(973 Program)(No.2012CB956003)the National Natural Science Foundation of China(Nos.41375093,41475082)+1 种基金supported in part by the Youth Elite Project of the CMAby the Typhoon Scientific and Technological Innovation Group of Shanghai Meteorological Service
文摘This study investigated the impact of sea surface temperature(SST)in several important areas of the Indian-Pacific basin on tropical cyclone(TC)activity over the western North Pacific(WNP)during the developing years of three super El Ni?o events(1982,1997,and 2015)based on observations and numerical simulations.During the super El Ni?o years,TC intensity was enhanced considerably,TC days increased,TC tracks mostly recurved along the coasts,and fewer TCs made landfall in China.These characteristics are similar to the strong ENSO-TC relationship but further above the climatological means than in strong El Ni?o years.It indicates that super El Ni?o events play a dominant role in the intensities and tracks of WNP TCs.However,there were clear differences in both numbers and positions of TC genesis among the different super El Ni?o years.These features could be attributed to the collective impact of SST anomalies(SSTAs)in the tropical central-eastern Pacific and East Indian Ocean(EIO)and the SST gradient(SSTG)between the southwestern Pacific and the western Pacific warm pool.During 2015,the EIO SSTA was extremely warm and the anomalous anticyclone in the western WNP was enhanced,resulting in fewer TCs than normal.In 1982,the EIO SSTA and spring SSTG showed negative anomalies,followed by an increased anomalous cyclone in the western WNP and equatorial vertical wind shear.This intensified the conversion of eddy kinetic energy from large-scale flows,favorable for the westward shift of TC genesis.Consequently,anomalous TC activities during the super El Ni?o years resulted mainly from combined SSTA impacts of different key areas over the Indian-Pacific basin.
文摘Tropical cyclones (TCs) and storms (TSs) are among the devastating events in the world and southwestern Indian Ocean (SWIO) in particular. The seasonal forecasting TCs and TSs for December to March (DJFM) and November to May (NM) over SWIO were conducted. Dynamic parameters including vertical wind shear, mean zonal steering wind and vorticity at 850 mb were derived from NOAA (NCEP-NCAR) reanalysis 1 wind fields. Thermodynamic parameters including monthly and daily mean Sea Surface Temperature (SST), Outgoing Longwave Radiation (OLR) and equatorial Standard Oscillation Index (SOI) were used. Three types of Poison regression models (i.e. dynamic, thermodynamic and combined models) were developed and validated using the Leave One Out Cross Validation (LOOCV). Moreover, 2 × 2 square matrix contingency tables for model verification were used. The results revealed that, the observed and cross validated DJFM and NM TCs and TSs strongly correlated with each other (p ≤ 0.02) for all model types, with correlations (r) ranging from 0.62 - 0.86 for TCs and 0.52 - 0.87 for TSs, indicating great association between these variables. Assessment of the model skill for all model types of DJFM and NM TCs and TSs frequency revealed high skill scores ranging from 38% - 70% for TCs and 26% - 72% for TSs frequency, respectively. Moreover, results indicated that the dynamic and combined models had higher skill scores than the thermodynamic models. The DJFM and NM selected predictors explained the TCs and TSs variability by the range of 0.45 - 0.65 and 0.37 - 0.66, respectively. However, verification analysis revealed that all models were adequate for predicting the seasonal TCs and TSs, with high bias values ranging from 0.85 - 0.94. Conclusively, the study calls for more studies in TCs and TSs frequency and strengths for enhancing the performance of the March to May (MAM) and December to October (OND) seasonal rainfalls in the East African (EA) and Tanzania in particular.
文摘The study investigated the influence of Tropical cyclone (TCs) to the plant productivity indices along the coast of Tanzania using both field observations and change detection methods. These indices are normally designed to maximize the sensitivity of the vegetation characteristics and are very crucial in monitoring droughts intensity, yield and biomass amongst others. The study used three types of satellite imageries including the 16 days Moderate Resolution Imaging Spectroradiometer (MODIS) of 250 <span><span><span style="font-family:;" "="">×<span> 250 m resolution;8 days Landsat 7 enhanced thematic mapper (ETM) with resolution of 30 </span>×<span> 30 m composites, and 5 Landsat 8 (LC8) images, to determine the patterns and the variability of the Normalized Difference Vegetation Index (NDVI) and En<span>hanced Vegetation Index (EVI) and TCs impacts on vegetation. Moreover, we</span> <span>used Tropical Rainfall Measuring Mission (TRMM) data and the daily to</span> monthly rainfall data from Tanzanian Meteorological Authority (TMA). The change detection between the pre and post storm (TCs) conditions was used to analyse inter annual variability of EVI over Chwaka, Rufiji and Pugu— Kazimzumbwi. The changes in NDVI and EVI and monthly rainfall at the coastal stations were calculated, plotted and analyzed. The results revealed that, highest EVI values over coastal Tanzania were observed during March <span>and April, and minimum (low) values in November. The results for EV</span>I changes based on pre and post storm conditions revealed that most observed stations and most TCs led to significant EVI changes which ranged from </span>-<span>0.05 to 0.19, and </span>-<span>0.3 to 0.22, for MODIS and L7 ETM data, respectively. As for the spatial changes in NDVI results revealed that, TCs (Besija and Fob<span>ane) </span><span>were associated with positive NDVI changes <i>i.e.</i> (enhancement) of >0.51 </span><span>an</span>d >0.31, and NDVI reduction (<i>i.e.</i> negative changes) of <0.02 and <</span>-<span>0.19 <span>for Chwaka and Rufiji, respectively. Besides the results revealed that, TCs episodes have induced a land cover changes from <i>i.e.</i> water covered areas</span> changed to be vegetation covered especially over the shorelines and inter tidal areas. Indeed, these results were consistent with the analysis of rainfall patterns which indicated that low rainfall occurred in low NDVI areas and vice versa.</span></span></span></span>
基金Supported by the National Natural Science Foundation of China(Nos.42122040,42076016)。
文摘Tropical cyclones constitute a major risk for coastal communities.To assess their damage potential,accurate predictions of their intensification are needed,which requires a detailed understanding of the evolution of turbulent heat flux(THF).By combining multiple buoy observations along the south north storm track,we investigated the THF anomalies associated with tropical storm Danas(2019)in the East China Sea(ECS)during its complete life cycle from the intensification stage to the mature stage and finally to its dissipation on land.The storm passage is characterized by strong winds of 10-20 m/s and a sea level pressure below 1000 hPa,resulting in a substantial enhancement of THF.Latent heat(LH)fluxes are most strongly affected by wind speed,with a gradually increasing contribution of humidity along the trajectory.The relative contributions of wind speed and temperature anomalies to sensible heat(SH)depend on the stability of the boundary layer.Under stable conditions,SH variations are driven by wind speed,while under near-neutral conditions,SH variations are driven by temperature.A comparison of the observed THF and associated variables with outputs from the ERA 5 and MERRA 2 reanalysis products reveals that the reanalysis products can reproduce the basic evolution and composition of the observed THF.However,under extreme weather conditions,temperature and humidity variations are poorly captured by ERA 5 and MERRA 2,leading to large LH and SH errors.The differences in the observed and reproduced LH and SH during the passage of Danas amount to 26.1 and 6.6 W/m^(2) for ERA 5,respectively,and to 39.4 and 12.5 W/m^(2) for MERRA 2,respectively.These results demonstrate the need to improve the representation of tropical cyclones in reanalysis products to better predict their intensification process and reduce their damage.
基金supportedby a grant from the Major State Basic Research Development Program of China(973Program)(No2011CB403500)the National Natural Science Foundation of China(NSFC)(NoU0733002)the Natural Science Foundation of Guangdong Province,China(No8351030101000002)
文摘Tropical cyclone (TC) Nargis (2008) made landfall in Myanmar on 02 May 2008, bringing a storm surge, major flooding, and resulting in a significant death toll. TC Nargis (2008) displayed abnormal features, including rare eastward motion in its late stage, rapid intensification before landing. Using reanalysis data and a numerical model, we investigated how a low-latitude westerly wind modulated TC Nargis’ (2008) track and provided favorable atmospheric conditions for its rapid intensification. More importantly, we found a possible counterbalance effect of flows from the two hemispheres on the TC track in the Bay of Bengal. Our analysis indicates that a strong westerly wind burst across the Bay of Bengal, resulting in TC Nargis’ (2008) eastward movement after its recurvature. This sudden enhancement of westerly wind was mainly due to the rapidly intensified mid-level cross-equatorial flow. Our results show that a high-pressure system in the Southern Hemisphere induced this strong, mid-level, cross-equatorial flow. During the rapid intensification period of TC Nargis (2008), this strong and broad westerly wind also transported a large amount of water vapor to TC Nargis (2008). Sufficient water vapor gave rise to continuously high and increased mid-level relative humidity, which was favorable to TC Nargis’ (2008) intensification. Condensation of water vapor increased the energy supply, which eventuated the intensification of TC Nargis (2008) to a category 4 on the Saffir-Simpson scale.
基金supported by the National Key Research&Development Program of China(Grant Nos.2017YFC1404100 and 2017YFC1404104)the National Natural Science Foundation of China(Grant Nos.41775100 and 41830964)。
文摘Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses to local warm sea surface temperatures and feedbacks,with aid from coherent coupled initialization.This study uses three sets of highresolution regional coupled models(RCMs)covering the Asia−Pacific(AP)region initialized with local observations and dynamically downscaled coupled data assimilation to evaluate the predictability of TC genesis in the West Pacific.The APRCMs consist of three sets of high-resolution configurations of the Weather Research and Forecasting−Regional Ocean Model System(WRF-ROMS):27-km WRF with 9-km ROMS,and 9-km WRF with 3-km ROMS.In this study,a 9-km WRF with 9-km ROMS coupled model system is also used in a case test for the predictability of TC genesis.Since the local sea surface temperatures and wind shear conditions that favor TC formation are better resolved,the enhanced-resolution coupled model tends to improve the predictability of TC genesis,which could be further improved by improving planetary boundary layer physics,thus resolving better air−sea and air−land interactions.
基金supported by the Liaoning Natural Science Foundation(No.L2010055)
文摘The scale, shape and position are three main factors to forecast tropical cyclone. The aim of the paper is to recognize tropical cyclone (TC) in the satellite cloud pictures according to the scale, shape and position of clouds. The study includes Canny edge detection, contour extraction and other techniques. The solutions are also established. The experiments show that the method can recognize the TC in the satellite pictures. The study is beneficial for TC track.
基金supported jointly by the National Natural Science Foundation of China(Grant Nos.40921160379,41025017and41105047)the Chinese Key Developing Program for Basic Sciences(Grant No.2009CB421405)
文摘The present study investigates modulation of western North Pacific (WNP) tropical cyclone (TC) genesis in relation to different phases of the intraseasonal oscillation (ISO) of ITCZ convection during May to October in the period 1979 2008. The phases of the ITCZ ISO were determined based on 30-80-day filtered OLR anomalies averaged over the region (5°20′N, 120°150′E). The number of TCs during the active phases was nearly three times more than during the inactive phases. The active (inactive) phases of ISO were characterized by low-level cyclonic (anticyclonic) circulation anomalies, higher (lower) midlevel relative humidity anomalies, and larger (smaller) vertical gradient anomalies of relative vorticity associated with enhanced (weakened) ITCZ convection anomalies. During the active phases, TCs tended to form in the center of the ITCZ region. Barotropic conversion from the low-level mean flow is suggested to be the major energy source for TC formation. The energy conversion mainly depended on the zonal and meridional gradients of the zonal flow during the active phases. However, barotropic conversion weakened greatly during the inactive phases. The relationship between the meridional gradient of absolute vorticity and low-level zonal flow indicates that the sign of the absolute vorticity gradient tends to be reversed during the two phases, whereas the same sign between zonal flow and the absolute vortieity gradient is more easily satisfied in the active phases. Thus, the barotropie instability of low-level zonal flow might be an important mechanism for TC formation over the WNP during the active phases of ISO.
基金National Natural Science Funding(41530427)State Key Laboratory of Severe Weather,Chinese Academy Meteorological sciences(2015LASW-A07)Project Supported by the Jiangsu Province Ordinary University Graduate Student Scientific Research and Innovation Program(CXZZ12_0495)
文摘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.
文摘Based on analyzing the surface air temperature series in the Southern and Northern Hemisphere and the tropical cyclone (TC) over the western North Pacific Ocean, the relationships between climatic warming and the frequency and intensity of tropical cyclone are investigated. The results showed that with the climatic warming in both hemispheres, the frequency of the tropical cyclone over the western North Pacific Ocean reduces and its intensity weakens simultaneously. A possible explanation might be that the cold air invasion from the Southern Hemisphere weakens due to global warming.
基金National Natural Science Foundation of China(41405060,41475082,41305049,41275067,41475059)
文摘The effects of vertical wind shear on tropical cyclone(TC) intensity change are examined based on the TC data from the China Meteorological Administration and the NCEP reanalysis daily data from 2001 to 2006.First,the influence of wind shear between different vertical levels and averages in different horizontal areas are compared.The results indicate that the effect of wind shear between 200 and 850 hPa averaged within a 200-800 km annulus on TC intensity change is larger than any other calculated vertical wind shear.High-latitude and intense TCs tend to be less sensitive to the effects of VWS than low-latitude and weak TCs.TCs experience time lags between the imposition of the shear and the weakening in TC intensity.A vertical shear of 8-9 m/s(9-10 m/s) would weaken TC intensity within 60 h(48 h).A vertical shear greater than 10 m/s would weaken TC intensity within 6 h.Finally,a statistical TC intensity prediction scheme is developed by using partial least squares regression,which produces skillful intensity forecasts when potential predictors include factors related to the vertical wind shear.Analysis of the standardized regression coefficients further confirms the obtained statistical results.
基金Natural Science Foundation of China (40175019) Key Public-Interest Project of the Ministryof Science and Technology of China (2001DIA20026)
文摘Conventional data and the Yearbook on Tropical Cyclones (TC) data from 1971 to 2000 are used to study the climate and disaster features of TC affecting the Liaodong Peninsula. Results indicate that interannual change of TC activities is obvious. Different sources of TC have different impacts on the area of interest. Intensity and moving speed of TC vary substantially in the progress of northward movement. Besides, tracks and damage distributions of TC are quite different.
基金Supported by the National Basic Research Program of China(973Program)(No.2012CB417402)the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences(No.LTO1510)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA11010102)the National Natural Science Foundation of China(No.41106018)the Funds for Creative Research Groups of China(No.41421005)the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1406401)
文摘To understand the impacts of large-scale circulation during the evolution of E1 Nifio cycle on tropical cyclones (TC) is important and useful for TC forecast. Based on best-track data from the Joint Typhoon Warning Center and reanalysis data from National Centers for Environmental Prediction for the period 1975- 2014, we investigated the influences of two types of E1 Nifio, the eastern Pacific E1 Nifio (EP-E1 Nifio) and central Pacific E1 Nifio (CP-E1 Nifio), on global TC genesis. We also examined how various environmental factors contribute to these influences using a modified genesis potential index (MGPI). The composites reproduced for two types of E1 Nifio, from their developing to decaying phases, were able to qualitatively replicate observed cyclogenesis in several basins except for the Arabian Sea. Certain factors of MGPI with more influence than others in various regions are identified. Over the western North Pacific, five variables were all important in the two E1Nifio types during developing summer (July-August-September) and fall (October- November-December), and decaying spring (April-May-June) and summer. In the eastern Pacific, vertical shear and relative vorticity are the crucial factors for the two types of El Nifio during developing and decaying summers. In the Atlantic, vertical shear, potential intensity and relative humidity are important for the opposite variation of EP- and CP-EI Nifios during decaying summers. In the Southern Hemisphere, the five variables have varying contributions to TC genesis variation during peak season (January-February-March) for the two types of E1 Nifio. In the Bay of Bengal, relative vorticity, humidity and omega may be responsible for clearly reduced TC genesis during developing fall for the two types and slightly suppressed TC cyclogenesis during EP-E1 Nifio decaying spring. In the Arabian Sea, the EP-E1 Nifio generates a slightly positive anomaly of TC genesis during developing falls and decaying springs, but the MGPI failed to capture this variation.
基金"Study on the Application of Satellite Data on the Elements of Military Meteorology andImportant Weather Watch" from the General Equipment Department of the People’s Liberation Army
文摘An objective technique of tropical cyclone (TC) moving direction prediction over the Northwestern Pacific Ocean during 2001 - 2002 is studied using GMS-50uting-Longwave Radiation (OLR)data. Three formulae used to predict TC moving direction in 6, 12 and 24 h, respectively, have been obtained based on a multiple linear regression framework and some regression factors including several kinds of OLR characteristic values and the minimum sea level pressure of tropical cyclone center. The multiple correlation coefficients of the statistical analysis using the information of TCs in the Yearbook on Tropical Cyclones to validate the satellite-based prediction are 0.954, 0.945 and 0.914 respectively. The results are satisfying through checking one of the TCs in 2001.The techniques could be applied in future operation and would contribute to TC movement prediction, especially to a sudden change in TC moving direction and improving the forecasting and warning capability.
基金Vicerrectoría de Investigacio′n,Universidad de Costa Rica for the grants C4106 and C4114funding of this research through the following Vicerrectoría de Investigacion,Universidad de Costa Rica grants:B9454 (supported by Fondo de Grupos),A4-906 (PESCTMA)and C2103funding of UCREA project C3991 and were partially supported by a grant awarded by the International Development Research Centre (IDRC)Ottawa,Canada,and the Central American University Council (CSUCA-SICA):Red Centroamericana de Ciencias sobre Cambio Clim´atico (RC4)project (C4468,CR-66,SIA 0054-2,the opinions expressed here do not necessarily represent those of IDRC,CSUCA or the Board of Governors).
文摘Tropical cyclones(TC)pose a persistent natural hazard to Costa Rica.Exposure to natural hazards,such as mass movements and floods,is compounded by a growing urban population and inadequate land use planning.This study conducted a comprehensive analysis of the economic impacts of TC of Costa Rica from Hurricane Joan in 1988 to Hurricane Eta in 2020,assessing the impact by municipality and economic sector using baseline information of the Ministry of National Planning and Economic Policy.According to the study,road infrastructure(933.8 US million),agriculture(280.5 US million),river rehabilitation(153.96 US million),housing 98.26(US million),and health(81.74 US million)were among the sectors most severely affected by TC over the past 30 years.The Pacific basin municipalities in Costa Rica were found to be the most vulnerable,primarily due to the indirect impacts of TC.The study's results offer useful information on the economic sectors and municipalities that are most exposed from TC in Costa Rica and provide a replicable methodology for other regions and countries facing similar tropical phenomena.