Global total precipitable water variations and trends during 1958-2021

TL;DR

This study analyzes global trends in total precipitable water and surface temperature from 1958 to 2021, revealing increases in water vapor and temperature consistent with climate change, validated across multiple datasets and observations.

Contribution

It provides a comprehensive assessment of TPW and temperature trends over six decades using improved reanalysis datasets and multiple observational sources, enhancing understanding of water vapor responses to warming.

Findings

Global TPW increased by 0.66-0.88% per decade.

Surface temperature warmed at 0.14 K per decade.

Water vapor response to temperature is 4-6% per Kelvin.

Abstract

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.