The Response Of Water Vapor To Temperature Change And Their Synergies In Precipitation Variability

The temporal-spatial variations of precipitation impose great impacts on the social economy and living environment under global warming.The internal relations among precipitation and water vapor content as well as temperature are researched in the dissertation.Focusing on the WV variation,whether the near-surface WV can reflect the total column WV content,and whether the WV can well respond to the variation of temperature are intended to be figured out.As for the precipitation variation,the relative importance of WV and temperature in the interannual variability of precipitation under the influence of circulation,and the relationship between precipitation and atmospheric static stability are intended to be figured out.By employing correlation analysis,compositing difference method and EOF decomposition,and linear regression in the main,the following conclusions are reached.1.In the interannual variation of WV,temperature plays a leading role in high latitudes,so the response of WV to temperature is closely in line with the C-C equation.In low latitudes,especially land areas,relative humidity plays a leading role.The large variation of relative humidity makes the response of WV to temperature deviate from the C-C equation.In the long-term variation of WV,on land at mid-to-low latitude,the result is similar to that of interannual variation,but the areas dominated by relative humidity are less.On the ocean,the effects of relative humidity are relatively large in the East Pacific and the Southern Ocean.The responses of WV to temperature are close to the C-C equation in the rest areas of the ocean.2.The near-surface WV pressure(SVP)can well reflect the interannual variation of precipitable water(PW)in extratropical areas,except in boreal summer.The correlations between SVP and PW are also weak in some coastal areas in the North Hemisphere in boreal summer.The SVP can well reflect the trend of PW,except in tropical Africa and the Indian Ocean.3.Influenced by the heat source over Tibet Plateau(TP),the precipitation anomalies in the Yangtze River Basin and the mid-to-downstream of the Yellow River Basin in midsummer are mainly caused by the anomaly of WV transport.In Northeast China,the precipitation anomalies are caused by both the anomalies of WV transport and temperature.Compared with the heat source of the whole plateau,the heat source in the western Tibet Plateau can better indicate the midsummer precipitation in China.There are positive correlations between spring heat source over TP and midsummer precipitation in the Yangtze River Basin,as well as some areas in Northeast China.And there is a negative correlation between spring heat source over TP and precipitation in mid-to-downstream of the Yellow River Basin.4.At interannual and long-term scales,the static stability and precipitation interact with each other.In the interannual variation,the influence of static stability on precipitation is more obvious in the lower troposphere over the ocean.The influence of precipitation on static stability is more obvious in the lower troposphere over continents and almost the whole midtroposphere.In the long-term variation,the distribution of the relationship between precipitation and static stability is more complicated in the lower troposphere.In the midtroposphere,the adjustments of precipitation on the static stability are more obvious.