Global total precipitable water variations and trends during 1958-2021

Global responses of the hydrological cycle to climate change have been widely studied but uncertainties of temperature responses to lower-tropospheric water vapor still remain. Here, we investigate the trends in global total precipitable water (TPW) and surface temperature from 1958 to 2021 using improved ERA5 and JRA-55 reanalysis datasets and further validate these trends by using radiosonde, Atmospheric Infrared Sounder (AIRS), and Microwave Satellite (SSMI(S)) observations. Our results indicate a global increase in total precipitable water (TPW) of 0.66% per decade according to ERA5 data and 0.88 % per decade in JRA-55 data.These variations in TPW reflect the interactions of global warming feedback mechanisms across different spatial scales. Our results also revealed a significant near-surface temperature (T2m) warming trend at the rate of 0.14 K dec-1 and a strong water vapor response to temperature at a rate of 4-6 % K -1 globally, with land areas warming approximately twice as fast as the oceans. The relationship between TPW and T2m or surface skin temperature Ts showed a variation around 6 - 8 % K -1 in the 15-60 latitude band, aligning with theoretical estimates from the Clausius Clapeyron equation.