The Persistent Anomaly Of Summer MJO And Its Stimulate And Increase Of ENSO

This article uses the MJO index data provided by CPC, RMM index data provided by the Australian stations, NECP reanalysis (including wind, temperature and pressure fields, etc.), Global Ocean Data Assimilation System provided by NOAA, CMAP precipitation data from 776 sites nationwide precipitation data and other data. The cycle characteristics and circulation features on Persistent Anomaly of MJO are analyzed, and Iip index is defined as described Persistent Anomaly of MJO. We found that persistent anomaly of summer MJO exists strong correlation between ENSO, and by composite analysis and example of a case we explores the internal mechanism of persistent anomaly of summer MJO influence Pacific ssta. We studied the impact of persistent anomaly of summer MJO to Asia summer monsoon rain belt advance. Finally, between persistent anomaly of summer MJO and the early Atlantic Ocean SSTA relations were discussed, and proposed the main reason of persistent anomaly of summer MJO appears.The results show:(1) We found that summer MJO activity center will stagnate, with insignificant eastward propagation. Two patterns of the persistent anomaly of MJO were seen:in the equatorial Pacific and in the equatorial Indian Ocean. When special circumstances that the persistent anomaly of MJO arise, the MJO cycle significantly has changed. For better describing the anomalous character of less obvious spread eastward MJO, we defines an index to describe the persistent anomaly of MJO. (2) After we analyzed the abnormal atmospheric circulation under the persistent anomaly of summer MJO condition found:If the summer MJO shows persistent abnormal activity in the equatorial Pacific Ocean (Indian Ocean), equatorial Walker circulation decreased (enhanced), Western Pacific Hadley Circulation strong (weak), West Pacific subtropical high northward (southwest), the equatorial Pacific Ocean (Indian Ocean) is an active area of convection, upper divergence. (3) Under the MJO for abnormal situation, summer circulation anomalies resulted in the difference in the monsoon and rainfall. In the high value of the Iip index, Somali Jet is northerly anomalies, and the tropical Indian Ocean monsoon was weaker. It led to the corresponding region of below normal rainfall. The 110°E the equatorial Western Pacific westerly and southerly air flow together to strengthen the tropical Pacific monsoon, Making tropical Western Pacific regional precipitation above normal. On the contrary, in the low value of the Iip index, Somali Jet stronger. Tropical Indian summer monsoon is stronger, corresponding Rainfall in the tropics, effecting subtropical regions above normal rains.Then, the tropical western Pacific monsoon is weak, resulting in the tropical western Pacific Less Rainfall. (4) They are proved to have high statistical correlations tothe later ENSO events in the autumn and winter seasons:When persistent anomaly of MJO happens in the Pacific Ocean in summer, El Nino events are often induced during the autumn and winter seasons of that year. However, during the other MJO mode whenthe summer persistent anomaly of MJO occursin the Indian Ocean, La Nina eventsoften follow instead. It can provide an initial basis for the related prediction of short-term climate prediction business. (5)The analysis of the atmospheric circulation field indicates that persistent anomaly of MJO can probably affect the entire Equatorial Pacific circulation, and results in wind stress anomalies. The wind stress anomalies could excitewarm or cold water masses whichpropagate eastwards at the subsurface ocean. The accumulation of warm or cold subsurface waterin the Equatorial Eastern Pacific Ocean may eventually lead to the formation of an ENSO. (6)After discussed the relationship between the Atlantic SST anomaly in the spring and persistent anomaly of summer MJO, we found:higher spring Atlantic SST will lead to summer MJO persistent anomaly in the Indian Ocean, the Atlantic SST in the spring on the low side leads to summer MJO persistent anomaly in the Pacific. Then we put forward the mechanism of spring Atlantic SST may affect summer lasts MJO anomalies. The air-sea interaction may have two paths:One is by SST inspire cyclone and anticyclone, affected the equator vertical circulation. In the summer the circulation situation led to strengthen or weaken the walker circulation, makes the equatorial anomaly updrafts appeared in the Indian Ocean or the eastern Pacific. Another path is in the north Atlantic tripole SST may inspire in the northern hemisphere CGT wave train, thus affecting the Indian Ocean region convection activities. In the study, we found that at first spring tropical Atlantic SSTA affect persistent anomaly of summer MJO, contributed to devastating summer MJO in the western Pacific active (inactive). Further, over the Pacific walker circulation is weakened (enhancement), makes the lower abnormal west wind (east wind) significantly. So the equatorial Pacific sea surface eastward (westward) wind stress anomaly, stimulate the east, and west Pacific subsurface water mass reverse trend of temperature change. Eventually led to the equatorial eastern Pacific SST anomaly warmer (colder), the impact on the formation of Autumn and Winter ENSO events. Therefore, spring Atlantic SSTA key area can be used as a judgment of ENSO events in Autumn and Winter.