Influence of Tropical Oceans on Middle and High Latitudes of Atmospheric Circulation Anomalies
|School||Ocean University of China|
|Keywords||In the high-latitude atmospheric circulation Wind anomaly olr abnormal Singular Value Decomposition Air-sea interaction|
In this paper, the outgoing longwave radiation NOAA 1974 ~ 2006 (hereinafter referred to as OLR) data, the NCEP 1948 to 2006 reanalysis monthly mean wind data, analysis of the El Ni? O Year, La Ni? A year of normal (non-El Ni ? Year o and non-La Ni? a), El Ni? o and the Indian Ocean dipole Year four cases typical month global anomaly wind field corresponding to the time of the tropical western Pacific (20 ° S-20 ° N) abnormal OLR distribution characteristics. The study found that abnormal OLR distribution for different circumstances tropical western Pacific and the corresponding distribution of the anomalous wind field, the difference is obvious. A year, whether with El Ni? O years or La Ni? Effective excitation the PJ (WP) away dependent wave train depends on the occurrence of the season. El Ni? August o and La Ni? A-year in July, October, especially coexist El Ni? O and the Indian Ocean dipole July, September, PJ (WP) teleconnection pattern wave column is the most obvious. Abnormal deep convection near the Philippines and the South China Sea over the tropical oceans of excitation (WP) teleconnection pattern wave train the most effective regional. Exception Bay of Bengal convection seems not associated wave train relations with East Asia, the Pacific coast away. At La Ni? A year, from spring to autumn, mid-latitudes over the East Asian coastal exists an obvious exception cyclonic circulation. The use of numerical models of atmospheric circulation experiments, the occurrence of the abnormal circulation exception of the ocean east of the Philippines convection heat related. Month by month the tropical western Pacific abnormal OLR field from 1980 to 2005 and the mid-latitudes of East Asia abnormal wind farm using singular value decomposition (SVD). The SVD analysis found that the contribution of the sum of the squares of the first three modal interpretations total covariance reached more than 95%, basically reflects the co-variation of Oceanic and Atmospheric atmosphere and ocean are mainly reflected in the first and second modes, while the The marine atmosphere dominated the first mode; previous three modal OLR averaged exhibit the in 0o ~ 14oN, 110o ~ 130oE high correlation. The analysis found that there are close contacts between the two abnormal heating field and anomalous wind field. OLR values ??of SST higher the tropical western Pacific Ocean, the region is lower over the more clouds, the more intense convective activity in the region, stimulate teleconnection wave train, thereby affecting the mid-latitude atmospheric circulation over the East Asian coastal Similarly, China the eastern coastal waters as well as in Northeast Asia over the atmospheric circulation changes through the monsoon circulation affecting the tropical western Pacific Ocean, resulting in changes in SST and convective activity, and thus constitute a possible positive feedback. Tropical regions annual scale, decadal scale abnormal OLR seasonal scale disturbances in the high-latitude synoptic scale wind field and geopotential height field the SVD analysis found over the tropical western Pacific interannual and decadal anomaly OLR field East Asian coastal areas, mid-latitude synoptic scale, seasonal scale wind farm has a close relationship; geopotential height field there is a close relationship between the the annual scale convection over the tropical western Pacific abnormal East Asian coastal synoptic scale disturbances. The reason might be the annual scale convection anomalies along the coast of East Asia over the synoptic scale systems favor the development of, and mid-latitude synoptic scale systems with westerly winds associated with a Rossby wave, Rossby wave energy development can be spread southeast, thereby affecting the tropical western Pacific Ocean. convective activity.