The Tropical Pacific Ocean is one of the areas experiencing the most active response of atmosphere to sea surface temperature (SST) anomaly. Understanding changes in the response of atmosphere to SST anomaly in the Tropical Pacific Ocean can help us to gain comprehensive knowledge of atmospheric circulation, ENSO, monsoon onset, typhoon activity and even physical/dynamical processes in the stratosphere. Based on the GFDL-ESM2G and CMCC-CESM models of CMIP5, the characteristics of the response of atmosphere to SST anomaly over the Tropical Pacific Ocean under the future RCP8.5 emission scenario are investigated. It is found that SST is increasing over the Tropical Pacific Ocean from 2006 to 2100 year by year. However, the correlations between SST and convective activities, 200 hPa geopotential height anomalies, vertical velocity anomalies over the Tropical Pacific Ocean are significantly weaker during 2080-2100 compared to those during 2006-2030. This indicates that along with the warming of the Tropical Pacific Ocean, there is a weakened response of atmosphere to SST anomaly in the future. The weakened response of atmosphere to SST anomaly over the Tropical Pacific Ocean further results in the weakened response of stratospheric temperature to the warm Tropical Pacific Ocean. The results of the CAM5 sensitivity test confirm that the response of atmosphere to SST anomaly over the Tropical Pacific Ocean is likely to weaken in the future. Further studies found that the regional average SST over the Tropical Pacific Ocean would increase from 27.4 °C during 2006-2030 to 29.4 °C during 2080-2100. Previous studies indicated that over the Tropical Pacific Oceans, deep convection linearly increases with increasing SST near 27.5 °C. However, once SST is more than 28 °C, further increases of SST appear to have little effect on convective intensification. Hence, in the future, the SST over the Tropical Pacific Ocean would exceed 28 °C, and further increases in SST actually suppress convective activities, which in turn leads to the weakened response of atmosphere to SST anomaly.

Based on monthly average reanalysis data from NCEP/NCAR from 1948 to 2016, the horizontal and vertical structure of the South Asia high (SAH) and their long-term variation characteristics were investigated. The results show that the horizontal structure of the SAH on 70 hPa, 100 hPa, 150 hPa and 200 hPa in different typical anomaly years appeared double centers mode and zonal and meridional enlargement, compared with the climatology state, but the horizontal width change of the SAH on different levels was different. The maximum wind speed of easterly jet constrained by internal air of the SAH weakened from 1948 to 2016 as a whole, while that of westerly jet had no significant change tendency. The dynamic and thermal vertical structures of the SAH including easterly jet, westerly jet, and air temperature anomaly were different during 1948-2016. The thickness of the SAH had obvious annual change, and it varied from 6.32 km to 6.42 km in the past 69 years. The geopotential height values of the SAH center on different levels rose about 0.1 gpkm during 1975-1980, and the east-west oscillation and south-north displacement of the central location were obvious, but the change ranges were different on different levels.