Based on various statistical methods and empirical orthogonal function (EOF) analysis, this study analyzes the correlation of radiation flux of Northwest Pacific in the 100 years scale with the western Pacific warm pool and typhoon development. The key results are as follows. First, the surface downwelling longwave radiation (SDLR) received by key areas in Northwest Pacific significantly increased over the past 170 years. The surface downwelling shortwave radiation (SDSR) decreased, and TOA (Top of Atmosphere) incident shortwave radiation (TISR) slightly fluctuated and increased in the 11a (11 years) period. Second, there was the strongest correlation between the Western Pacific warm pool and SDLR, and both increased continuously. Third, since 1945, there has been a tendency of increasing after decreasing in the annual frequency and the share of severe typhoons, and the formation area distribution of typhoons has turned more even. Taking 1998 as a cut-off point, before 1998, there was no obvious correlation between the strong typhoon frequency and SDLR. However, such correction became stronger after 1998. They were affected by the changes of SDLR, SDSR, TISR, vapor, vorticity, vertical velocity, SST and h100 . Forth, the SDLR and TISR are major factors influencing the Western Pacific warm pool, typhoon motion and other varieties. While SDLR mainly increases in the tropical areas, TISR tends to fluctuate and increase slightly. Their changes are consistent with the change general characteristics of strengthening of typhoon.

We used synthetic analysis, EOF decomposition, correlation coefficient analysis and causal analysis to investigate relationships between radiation flux and ENSO in the tropical Pacific in recent 170a. Our results indicate that SDLR increased significantly, by c.0.05 W / (M 2 * a), TOLR decreased slightly, by c.0.02 W / (M 2 * a), SDSR did not change significantly, and TISR increased slightly, by c.0.001 W / (M 2 * a). In the tropical western Pacific region, the average state of the tropospheric atmosphere rising and sinking intersecting area shifted eastward by 0.05 ° / a, and El Niño Modoki events increased. In the Middle East Pacific, especially Niño 3.4 with an ocean depth > 700 m, ocean heat content increased significantly, the maximum ILD region moved eastward, upward movement in the intersecting area was abnormally enhanced, the number of westerly wind bursts weakened, and the probability of El Niño Modoki occurrence increased. There was a correlation and causal relationship between marine heat content in zones Niño3 and Niño4, radiation flux, w and u, v anomalies near the intersecting zone. When the time series of the factor was ahead or behind, the lead lag correlation coefficient generally increased. The location of the ILD maximum only affected TOLR, and only SDLR can affect the longitudinal location of the ILD maximum. The longitudinal location of the ILD maximum and H niño3 , H niño3.4 interact as both cause and effect.