The relationship between the variability of the Eastern India Ocean Warm Pool (EIWP) and the spring precipitation in China is studied in the paper based on an analysis of the Simple Ocean Data Assimilation (SODA) Sea ...The relationship between the variability of the Eastern India Ocean Warm Pool (EIWP) and the spring precipitation in China is studied in the paper based on an analysis of the Simple Ocean Data Assimilation (SODA) Sea Surface Temperature (SST) data, the reanalysis data of monthly grid wind field at 925 hPa with a resolution of 2.5° latitude and longitude from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR),and the monthly mean rainfall data from 160 observational stations in China. The results show that there is a strong correlation between the EIWP variability and the spring precipitation in China. The area, volume and intensity indices of the EIWP are negatively correlated with the spring precipitation in southwestern China, while they are positively correlated with the spring precipitation in the rest of China, especially in the northeast. For this correlation between the EIWP variability and the spring precipitation in China, it is found that the correlative relationship is mainly connected with the variations of the moisture transport by the warm air flow, which is under the influence of the EIWP variability, into the inland of China in spring. Two causative factors may influence this transport. One is the variation of the moisture transport carried by the warm air flow from the Arabian Sea influenced by the EIWP variability. The other is the variation of the equator-crossing flow (70°-90°E) influenced by the EIWP anomaly in the previous winter which exerts its effect on the moist warm air transported from the Southern Hemisphere. The position and intensity of the Western North Pacific Subtropical High (WNPSH)variability caused by EIWP variation also influence the spring precipitation in China.展开更多
Using the 1980-2010 winter GODAS oceanic assimilations, study is conducted of the winter heat content(HC) established in the subsurface layer(5 to 366 m in depth) over the western Pacific warm pool(WP), followed by in...Using the 1980-2010 winter GODAS oceanic assimilations, study is conducted of the winter heat content(HC) established in the subsurface layer(5 to 366 m in depth) over the western Pacific warm pool(WP), followed by investigating the HC spatiotemporal characteristics, persistence and the impacts on the climate anomalies of neighboring regions. Results are as follows: 1) the pattern of integral consistency is uncovered by the leading EOF1(PC1) mode of HC interannual variability, the year-to-year fluctuation of the time coefficients being well indicative of the interannual anomaly of the WP winter subsurface-layer thermal regime. The HC variation is bound up with El Ni觡o-Southern Oscillation, keeping pronounced autocorrelation during the following two seasons and more, with the persistence being more stable in comparison to sea surface temperature anomaly in the equatorial middle eastern Pacific; 2) the winter HC anomalies produce lasting effect on the WP thermal state in the following spring and summer and corresponding changes in the warm water volume lead to the meridional transport and vertical exchange of warm water, which exerts greater impacts upon the sea surface temperature/heat flux over the warm pool per se and neighboring regions, especially in the Philippine Sea during the posterior spring and summer; 3) the increase in the winter HC corresponds to the spring outgoing longwave radiation(OLR) decrease and richer precipitation over the waters east to the Philippine Sea and the resultant convective heating anomalies are responsible for the rise of geopotential isobaric surfaces over tropical and subtropical western North Pacific, thereby producing effect on the western Pacific subtropical high(anomaly). Subsequently, the sea-surface heat flux exchange is intensified in the warm pool, a robust anomalous cyclone shows up at lower levels, air-sea interactions are enhanced and abnormal convective heating occurs, together making the winter HC anomalies even more closely associated with the variation in the summer subtropical high. As a result, the WP winter HC can be used as an effective predictor of the variation in spring/summer western Pacific subtropical high and the strength of summer monsoon over the northwestern Pacific.展开更多
基金This research is supported Sciences Foundation of China by the National Natural(No.40305009).
文摘The relationship between the variability of the Eastern India Ocean Warm Pool (EIWP) and the spring precipitation in China is studied in the paper based on an analysis of the Simple Ocean Data Assimilation (SODA) Sea Surface Temperature (SST) data, the reanalysis data of monthly grid wind field at 925 hPa with a resolution of 2.5° latitude and longitude from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR),and the monthly mean rainfall data from 160 observational stations in China. The results show that there is a strong correlation between the EIWP variability and the spring precipitation in China. The area, volume and intensity indices of the EIWP are negatively correlated with the spring precipitation in southwestern China, while they are positively correlated with the spring precipitation in the rest of China, especially in the northeast. For this correlation between the EIWP variability and the spring precipitation in China, it is found that the correlative relationship is mainly connected with the variations of the moisture transport by the warm air flow, which is under the influence of the EIWP variability, into the inland of China in spring. Two causative factors may influence this transport. One is the variation of the moisture transport carried by the warm air flow from the Arabian Sea influenced by the EIWP variability. The other is the variation of the equator-crossing flow (70°-90°E) influenced by the EIWP anomaly in the previous winter which exerts its effect on the moist warm air transported from the Southern Hemisphere. The position and intensity of the Western North Pacific Subtropical High (WNPSH)variability caused by EIWP variation also influence the spring precipitation in China.
基金National Key Basic Research/Development Project(2012CB417403)Public Sector(Meteorology)Special Research Foundation(GYHY201306022,GYHY201406024)+1 种基金Foundation of National Natural Sciences(41205065)Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions
文摘Using the 1980-2010 winter GODAS oceanic assimilations, study is conducted of the winter heat content(HC) established in the subsurface layer(5 to 366 m in depth) over the western Pacific warm pool(WP), followed by investigating the HC spatiotemporal characteristics, persistence and the impacts on the climate anomalies of neighboring regions. Results are as follows: 1) the pattern of integral consistency is uncovered by the leading EOF1(PC1) mode of HC interannual variability, the year-to-year fluctuation of the time coefficients being well indicative of the interannual anomaly of the WP winter subsurface-layer thermal regime. The HC variation is bound up with El Ni觡o-Southern Oscillation, keeping pronounced autocorrelation during the following two seasons and more, with the persistence being more stable in comparison to sea surface temperature anomaly in the equatorial middle eastern Pacific; 2) the winter HC anomalies produce lasting effect on the WP thermal state in the following spring and summer and corresponding changes in the warm water volume lead to the meridional transport and vertical exchange of warm water, which exerts greater impacts upon the sea surface temperature/heat flux over the warm pool per se and neighboring regions, especially in the Philippine Sea during the posterior spring and summer; 3) the increase in the winter HC corresponds to the spring outgoing longwave radiation(OLR) decrease and richer precipitation over the waters east to the Philippine Sea and the resultant convective heating anomalies are responsible for the rise of geopotential isobaric surfaces over tropical and subtropical western North Pacific, thereby producing effect on the western Pacific subtropical high(anomaly). Subsequently, the sea-surface heat flux exchange is intensified in the warm pool, a robust anomalous cyclone shows up at lower levels, air-sea interactions are enhanced and abnormal convective heating occurs, together making the winter HC anomalies even more closely associated with the variation in the summer subtropical high. As a result, the WP winter HC can be used as an effective predictor of the variation in spring/summer western Pacific subtropical high and the strength of summer monsoon over the northwestern Pacific.
