Trends in precipitable water vapor in North America based on GNSS observation and ERA5 reanalysis
摘要
Atmospheric precipitable water vapor (PWV) is a very important meteorological factor for weather forecasting and climate change monitoring. GNSS and ERA5 PWV from 2010 to 2022 are used to analyze the mean distribution and interdecadal trend of PWV in North America. The mean PWV is less than 20 mm in most regions of North America except for the Southeast. Overall, there is a significant increase along the Atlantic coast region of southeast North America and near the Gulf of California. ERA5-PWV values from 1940 to 2022 are used to analyze the interdecadal trend of PWV in North America. The results show that the trend of PWV remains unchanged for the east of Rocky Mountains. Most of the other regions are experiencing extremely significant increases, with the fastest rising interdecadal trend of around 1.2 mm decade−1 in summer near the Gulf of California. The results illustrate that there is a significant correlation between PWV and temperature with the correlation coefficient of 0.96, and that there are some differences between the actual increase and ideal increase of water vapor derived from Clausius-Clapeyron equation for every 1 K increase in North America. In addition, the response of PWV to ENSO in North America includes a delay of six to ten months and a fluctuation from 1.5 to 3 mm after El Niño events. The results indicate that ENSO events have an important influence on PWV change, and the effect of ENSO on PWV in tropical regions is greater than that in temperate regions.