This study proposes a new explanation for the formation of precipitation anomaly patterns in the boreal summer during the E1 Nifio-Southem Oscillation （ENSO） developing and decaying phases. During the boreal sum- me...This study proposes a new explanation for the formation of precipitation anomaly patterns in the boreal summer during the E1 Nifio-Southem Oscillation （ENSO） developing and decaying phases. During the boreal sum- mer June-July-August （JJA） （0） of the E1 Nino （La Nina） developing phase, the upper level （300-100 hPa） positive potential temperature anomalies resemble a Ma- tsuno-Gill-type response to central Pacific heating （cool- ing）, and the lower level （1000-850 hPa） potential tem- perature anomalies are consistent with local SST anoma- lies. During the boreal summer JJA（1） of the E1 Nifio （La Nifia） decaying phase, the upper level potential tempera- ture warms over the entire tropical zone and resembles a Matsuno-Gill-type response to Indian Ocean heating （cooling）, and the lower level potential temperature anomalies follow local SST anomalies. The vertical heterogeneity of potential temperature anomalies influences the atmospheric stability, which in turn influences the precipitation anomaly pattern. The results of numerical experiments confirm our observations.展开更多
基金supported by the National Basic Research Program of China (2006CB400503)the National Natural Science Foundation of China (40890155,40775051,and U0733002)Project KZCX2-YW-220 of the Chinese Academy of Sciences
文摘This study proposes a new explanation for the formation of precipitation anomaly patterns in the boreal summer during the E1 Nifio-Southem Oscillation （ENSO） developing and decaying phases. During the boreal sum- mer June-July-August （JJA） （0） of the E1 Nino （La Nina） developing phase, the upper level （300-100 hPa） positive potential temperature anomalies resemble a Ma- tsuno-Gill-type response to central Pacific heating （cool- ing）, and the lower level （1000-850 hPa） potential tem- perature anomalies are consistent with local SST anoma- lies. During the boreal summer JJA（1） of the E1 Nifio （La Nifia） decaying phase, the upper level potential tempera- ture warms over the entire tropical zone and resembles a Matsuno-Gill-type response to Indian Ocean heating （cooling）, and the lower level potential temperature anomalies follow local SST anomalies. The vertical heterogeneity of potential temperature anomalies influences the atmospheric stability, which in turn influences the precipitation anomaly pattern. The results of numerical experiments confirm our observations.
