Ocean surface winds observed by the Quick Scatterometer(QuikSCAT) satellite prior to the geneses of 36 tropical cy-clones(TCs) in the South China Sea(SCS) are investigated in this paper. The results show that there ar...Ocean surface winds observed by the Quick Scatterometer(QuikSCAT) satellite prior to the geneses of 36 tropical cy-clones(TCs) in the South China Sea(SCS) are investigated in this paper. The results show that there are areas with negative mean horizontal divergence around the TC genesis locations three days prior to TC formation. The divergence term [-(f+ζ)(u/x+v/y) ] in the vorticity equation is calculated based upon the QuikSCAT ocean surface wind data. The calculated mean divergence term is about 10.3 times the mean relative vorticity increase rate around the TC genesis position one day prior to TC genesis,which shows the important contributions of the divergence term to the vorticity increase prior to TC formation. It is suggested that criteria related with the divergence and divergence term be applied in early detections of tropical cyclogenesis using the QuikSCAT satellite data.展开更多
An index of a large-scale Kuroshio Extension（KE） sea surface height dipole（KED） mode is constructed using satellite altimeter sea level anomaly observations from January 1993 to December 2015 based on previous wor...An index of a large-scale Kuroshio Extension（KE） sea surface height dipole（KED） mode is constructed using satellite altimeter sea level anomaly observations from January 1993 to December 2015 based on previous work of the second author. It is found that the KED mode that undergoes a decadal variation from a negative phase（a positive-over-negative dipole, KED.） to a positive phase（a negative-over-positive dipole, KED＋） can affect the variability of the oceanic SST front and the North Pacific storm track. The results show that the oceanic SST fronts in the north of the KE region and in the KE region — referred to as the NSST and KSST fronts, respectively — are closely correlated with the KED mode. In the NSST front region, the SST front is stronger for KED. than for KED＋, and the opposite is the case in the KSST region. It is further revealed that the decadal phase transition of the KED mode can change the location and strength of the North Pacific storm track, with the North Pacific storm track being slightly weaker and moving more northwards as a whole during the KED. mode than during the KED＋ mode. The westerly wind associated with the storm track on the downstream side of the KE region intensifies and shifts northwards under KED. compared to KED＋.Furthermore, the transition of the KED mode gives rise to changes in the North Pacific storm track by changing the NSST and KSST fronts and meridional heat flux.展开更多
A rapid environmental assessment was conducted by the staff of Marine Biology Research Center （CIBIMA）, Faculty of Sciences, Universidad Aut6noma de Santo Domingo （UASD） on the southern coast of the Dominican Repu...A rapid environmental assessment was conducted by the staff of Marine Biology Research Center （CIBIMA）, Faculty of Sciences, Universidad Aut6noma de Santo Domingo （UASD） on the southern coast of the Dominican Republic, to evaluate the effects of the hurricane Matthew on October 3, being the 14th storm of the year 2016 for the Caribbean region. The observations were carried out two weeks after the storm hit. These observations included coastal ecosystems, such as marshes, beaches, lagoons, wetlands, mangrove forests, nearshore sea grasses and coral reefs. The evaluation included observations on the magnitude of the distresses and levels of destruction---changes, produced by the intense weather and upset climate from the storm. The data gathered were recorded following a categorization of impacts. It also included a description of the different coastal communities after being impacted and affected by the storm.展开更多
Based on 60-year （1951-2010） reanalysis data of the National Oceanic and Atmospheric Administration and extended reconstructed sea surface temperatures, a detailed investigation was conducted to explore the midwinte...Based on 60-year （1951-2010） reanalysis data of the National Oceanic and Atmospheric Administration and extended reconstructed sea surface temperatures, a detailed investigation was conducted to explore the midwinter storm track changes over the North Pacific. The root- mean-square （rms） of subweekly （2.5-6 days） transient of 300 hPa geopotential height field was calculated to represent the storm track. A decadal abruption occurred in 1982/1983, according to the Mann-Kendall test result. The first two Empirical Orthogonal Function （EOF） spatial patterns of the North Pacific storm track during P1 （1955-1982） and P2 （1983-2010） revealed opposite results：The EOF1 during P1 and the EOF2 during P2 revealed changes of intensity of the midwinter storm track in the North Pacific, whereas the EOF2 during P1 and the EOF1 during P2 exhibited a southward/northward shift of its central axis. In addition, pronounced differences in the thermal influence of the ocean on the storm track during P1 and P2 existed. A strong and sustained ENSO signal contributed to a storm track variation through the westerly jet from1955 to 1982, as the storm track was observed to strengthen and shift equatorward during El Ni6o events. From 1983 to 2010, an apparent sea temperature frontal zone at approximately 40°N and the associated near-surface baroclinicity resulted in the organization of a prominent mid-latitude storm track throughout the depth of the troposphere.展开更多
Based on tropical cyclone datasets from Shanghai Typhoon Institute of China Meteorological Administration,the National Centers for Environmental Prediction (NCEP,USA) reanalysis data and the rainfall records from 743 ...Based on tropical cyclone datasets from Shanghai Typhoon Institute of China Meteorological Administration,the National Centers for Environmental Prediction (NCEP,USA) reanalysis data and the rainfall records from 743 stations in China,the impacts of cyclogenesis number over the South China Sea and the western Pacific are studied on the 30-60-day oscillations in the precipitation of Guangdong during the flooding period.The year with more-than-normal (less-than-normal) tropical cyclogenesis is defined as a 'high year' ('low year').In light of the irregular periodic oscillations,the method used to construct the composite life cycle is based on nine consecutive phases in each of the cycles.Phases 1,3,5,and 7 correspond to,respectively,the time when precipitation anomalies reach theminimum,a positive transition (negative-turning-to-positive) phase,the maximum,and a negative transition phase.The results showed that the precipitation of the 30-60-day oscillations is associated with the interaction between a well-organized eastward propagation system from the Arabian Sea/Bay of Bengal and a westward-propagating system (with cyclonic and anticyclonic anomalies in the northwest-southeast direction) from the South China Sea to western Pacific during the high years,whereas the precipitation is affected during a low year by the circulation over the South China Sea and western Pacific (with cyclonic and anticyclonic anomalies in the northeast-southwest direction).During the high year,the warm and wet air mass from the ocean to the west and south are transported to Guangdong by westerly anomalies and an enclosed latitudinal cell,which ascends in the Northern Hemisphere low latitudes and descends in the Southern Hemisphere low latitudes.During the low year,the warm and wet air mass from the ocean to the south is transported to Guangdong by southwesterly wind anomalies and local ascending movements.Because the kinetic energy,westerly,easterly shift,vertical velocity and vapor transportation averaged over (109-119° E,10-20° N) is stronger in high years than those in low years,the precipitation of the 30-60-day oscillations in Guangdong is higher in high years than that in low years.展开更多
文摘Ocean surface winds observed by the Quick Scatterometer(QuikSCAT) satellite prior to the geneses of 36 tropical cy-clones(TCs) in the South China Sea(SCS) are investigated in this paper. The results show that there are areas with negative mean horizontal divergence around the TC genesis locations three days prior to TC formation. The divergence term [-(f+ζ)(u/x+v/y) ] in the vorticity equation is calculated based upon the QuikSCAT ocean surface wind data. The calculated mean divergence term is about 10.3 times the mean relative vorticity increase rate around the TC genesis position one day prior to TC genesis,which shows the important contributions of the divergence term to the vorticity increase prior to TC formation. It is suggested that criteria related with the divergence and divergence term be applied in early detections of tropical cyclogenesis using the QuikSCAT satellite data.
基金supported by the National Basic Research Program of China[grant number 2013CB956203]the National Natural Science Foundation of China[grant number 41490642]
文摘An index of a large-scale Kuroshio Extension（KE） sea surface height dipole（KED） mode is constructed using satellite altimeter sea level anomaly observations from January 1993 to December 2015 based on previous work of the second author. It is found that the KED mode that undergoes a decadal variation from a negative phase（a positive-over-negative dipole, KED.） to a positive phase（a negative-over-positive dipole, KED＋） can affect the variability of the oceanic SST front and the North Pacific storm track. The results show that the oceanic SST fronts in the north of the KE region and in the KE region — referred to as the NSST and KSST fronts, respectively — are closely correlated with the KED mode. In the NSST front region, the SST front is stronger for KED. than for KED＋, and the opposite is the case in the KSST region. It is further revealed that the decadal phase transition of the KED mode can change the location and strength of the North Pacific storm track, with the North Pacific storm track being slightly weaker and moving more northwards as a whole during the KED. mode than during the KED＋ mode. The westerly wind associated with the storm track on the downstream side of the KE region intensifies and shifts northwards under KED. compared to KED＋.Furthermore, the transition of the KED mode gives rise to changes in the North Pacific storm track by changing the NSST and KSST fronts and meridional heat flux.
文摘A rapid environmental assessment was conducted by the staff of Marine Biology Research Center （CIBIMA）, Faculty of Sciences, Universidad Aut6noma de Santo Domingo （UASD） on the southern coast of the Dominican Republic, to evaluate the effects of the hurricane Matthew on October 3, being the 14th storm of the year 2016 for the Caribbean region. The observations were carried out two weeks after the storm hit. These observations included coastal ecosystems, such as marshes, beaches, lagoons, wetlands, mangrove forests, nearshore sea grasses and coral reefs. The evaluation included observations on the magnitude of the distresses and levels of destruction---changes, produced by the intense weather and upset climate from the storm. The data gathered were recorded following a categorization of impacts. It also included a description of the different coastal communities after being impacted and affected by the storm.
基金supported by The National Natural Science Foundation of China[grant number 41421004]
文摘Based on 60-year （1951-2010） reanalysis data of the National Oceanic and Atmospheric Administration and extended reconstructed sea surface temperatures, a detailed investigation was conducted to explore the midwinter storm track changes over the North Pacific. The root- mean-square （rms） of subweekly （2.5-6 days） transient of 300 hPa geopotential height field was calculated to represent the storm track. A decadal abruption occurred in 1982/1983, according to the Mann-Kendall test result. The first two Empirical Orthogonal Function （EOF） spatial patterns of the North Pacific storm track during P1 （1955-1982） and P2 （1983-2010） revealed opposite results：The EOF1 during P1 and the EOF2 during P2 revealed changes of intensity of the midwinter storm track in the North Pacific, whereas the EOF2 during P1 and the EOF1 during P2 exhibited a southward/northward shift of its central axis. In addition, pronounced differences in the thermal influence of the ocean on the storm track during P1 and P2 existed. A strong and sustained ENSO signal contributed to a storm track variation through the westerly jet from1955 to 1982, as the storm track was observed to strengthen and shift equatorward during El Ni6o events. From 1983 to 2010, an apparent sea temperature frontal zone at approximately 40°N and the associated near-surface baroclinicity resulted in the organization of a prominent mid-latitude storm track throughout the depth of the troposphere.
基金Key National Fundamental Research and Development Project "973" Program (2006CB403600)Natural Science Foundation of China (40775058)Project of Science and Technology Program of Guangdong Province (2005B32601007)
文摘Based on tropical cyclone datasets from Shanghai Typhoon Institute of China Meteorological Administration,the National Centers for Environmental Prediction (NCEP,USA) reanalysis data and the rainfall records from 743 stations in China,the impacts of cyclogenesis number over the South China Sea and the western Pacific are studied on the 30-60-day oscillations in the precipitation of Guangdong during the flooding period.The year with more-than-normal (less-than-normal) tropical cyclogenesis is defined as a 'high year' ('low year').In light of the irregular periodic oscillations,the method used to construct the composite life cycle is based on nine consecutive phases in each of the cycles.Phases 1,3,5,and 7 correspond to,respectively,the time when precipitation anomalies reach theminimum,a positive transition (negative-turning-to-positive) phase,the maximum,and a negative transition phase.The results showed that the precipitation of the 30-60-day oscillations is associated with the interaction between a well-organized eastward propagation system from the Arabian Sea/Bay of Bengal and a westward-propagating system (with cyclonic and anticyclonic anomalies in the northwest-southeast direction) from the South China Sea to western Pacific during the high years,whereas the precipitation is affected during a low year by the circulation over the South China Sea and western Pacific (with cyclonic and anticyclonic anomalies in the northeast-southwest direction).During the high year,the warm and wet air mass from the ocean to the west and south are transported to Guangdong by westerly anomalies and an enclosed latitudinal cell,which ascends in the Northern Hemisphere low latitudes and descends in the Southern Hemisphere low latitudes.During the low year,the warm and wet air mass from the ocean to the south is transported to Guangdong by southwesterly wind anomalies and local ascending movements.Because the kinetic energy,westerly,easterly shift,vertical velocity and vapor transportation averaged over (109-119° E,10-20° N) is stronger in high years than those in low years,the precipitation of the 30-60-day oscillations in Guangdong is higher in high years than that in low years.
