| Low-Latitude Plateau located at southwest China, is the water source of many rivers. Flash floods, landslides, mudslides, drought and other natural disasters were occurred frequently. The precipitation’s temporal and spatial distribution is extremely uneven. Since2009, a drought successive years took place which not be seen since meteorological records, and had a great impact on the production and life of the people. It has a very important practical significance for disaster reduction and prevention, and strengthening the use of water resources to improve the precipitation forecast level in Latitude Plateau. In this paper, on the basis of previous studies, the ERA-interim reanalysis data of European Centre for Medium-Range Weather Forecasts, HadIsst sea temperature data set of the Met Office Hadley Centre, low-latitude plateau precipitation data, forecast results have been used by integrated application analysis, power spectrum analysis, extended singular value decomposition(ESVD) and other statistical diagnostic methods to study the basic features of the Indian Ocean warm pool, the western Pacific warm pool and Low-Latitude plateau precipitation, their interannual variability, their relationship, the atmosphere-ocean interaction and it’s processes and physical mechanisms. The numerical model COSMOS1.2.1was used for further analysis and verification.(1) By using synthetic analysis, correlation analysis and power spectral analysis method, the basic characteristics of the air-sea interaction in the Indo-Pacific warm pool have been analyzed. The analyses results show that the Indo-Pacific warm pool latent heat flux and sensible heat fluxes positive, and have positive effect on the heating of the oceans to the atmosphere in summer. Average sensible heat flux and its interannual variations of anomalies are smaller an order of magnitude than that of the latent heat flux. The changes of latent heat flux and sensible heat flux have remarkable consistency in Indo-Pacific warm pool in June, July and August. In summer, the latent heat flux over Indian Ocean warm pool is about20W/m2more than that over the western Pacific warm pool and sensible heat flux over the western Pacific warm pool is about2W/m2more than that over the Indian Ocean warm pool. Live data analysis and numerical simulation results show that there is obvious inter annual and decadal cycle changes of air-sea interaction in the warm pool area. The Interannual changes have the cycles of quasi2yearsand4-6years, and quasi-decadal changes have the cycles of quasill yearsand16years.(2) By ESVD method, low-latitude plateau precipitation fields are analyzed with the left fields which are composed of latent heat flux and sensible heat flux. More and better results have been gotten. The three singular precipitation fields in June, July and August has the same symbols. It represents the precipitation of different stations is above normal or below normal in the same time. According to the Decomposition result of each month, after defining the positive and negative abnormal years, the difference of elements of the atmospheric circulation was been analyzed. Heat flux anomalies affecting the low-latitude plateau precipitation process has the same basic physical processes in June and July. In June and July, when latent heat flux in the middle and northern Indian Ocean warm pool is in positive anomaly and in the northeastern part of the Western Pacific Warm Pool is negative abnormal, The atmospheric becomes warmer and wetter in northern Indian Ocean and in western WPWP, to procure low pressure development to the northern part of the South China Sea and the northern part of the Bay of Bengal, strengthen the monsoon circulation, make the inter tropical convergence zone(ITCZ)enhanced and extended northward, and provides favorable conditions of moisture transport and power convergence, thus making the low latitude plateau precipitation increased in June and July. There are quite different physical processes between August and June, July. In August, when the Northeast IWP and northwest WPWP latent heat flux are in negative anomaly, the heat and water vapor transport reduce from marine to atmospheric in this region, leading to abnormal development of high in the northern South China Sea and the northern Bay of Bengal, and moisture transport in high-voltage peripheral air flow increased to low latitude plateau. Abnormal development of two high-pressure causes low latitude plateau located in the convergence zone between the two high, the ITCZ enhanced and extended northward, and provides favorable conditions for the power condition of precipitation in low latitude plateau, making low latitude plateau area precipitation increasing.(3)ESVD analysis and the simulation results show that there is an obvious positive feedback process between the latent heat flux and atmospheric circulation in IPWP. Low pressure disturbance will lead to the ground wind speed increases. The increase of wind speed will make latent heat flux increases. The atmosphere will get more latent heating and water vapor transport from the ocean. The release of the latent heat will lead the development of low pressure and convection. Wind speed will further increase so to form a mutual promotion of positive feedback process. The reaction of SST and sensible heat flux responding to abnormal latent heat flux curbs this positive feedback process. There is certain regularity in the latent heat flux anomalies location and atmospheric circulation anomalies in Indo-Pacific warm pool region. Vertical velocity anomalies and precipitation anomalies are north to heat flux anomalies and surface wind speed anomaly centers3-4latitude degree. The Lower circulation anomalies center and surface pressure anomalies center are north to7-9latitude degree.(4) Numerical model has simulated the basic characteristics of air-sea interaction over the Indo-Pacific warm pool area well. According to ESVD singular vectors of latent heat flux field, the simulation time coefficients were constructed. Difference synthesis analysis is executed. By ESVD analysis, the numerical model reproduced the abnormal morphology of the air-sea interaction. Mode analysis results show that the physical processes of air-sea interaction affecting the Low Latitude Plateau summer precipitation is correct.(5) Integrated full-text analysis results, the physical model in June and July and August, of air-sea interaction anomaly is established. The June and July’s model:when the latent heat flux in the north Indian Ocean warm pool has positive (negative) anomalies, the western Pacific warm pool west has positive (negative) anomalies and northeast has negative (positive) anomalies, heat and water vapor transport are more(less) in the oceans of the northern IWP and western WPWP, Leading to the development of low (high) from north South China Sea to north Bay of Bengal, strengthening (weakening) water vapor transport to low-latitude plateau region, strengthening (weakening) the power convergence, and finally causing more(less) precipitation in Low Latitude Plateau. The model of August:When the latent heat flux over middle and north IWP and west WPWP is negative(positive) abnormal, there are more (less) heating to atmosphere and water vapor transport, leading to the high pressure anomaly development (weakened) over north of South China Sea, north of the Bay of Bengal, causing high-voltage peripheral air flow to Low Latitude Plateau water vapor transported enhanced (weakened), easy (not easy) to forming two high convergence in the low-latitude plateau region, then resulting in more (less) precipitation in low latitude plateau. |
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