Upper Tropospheric and Lower Stratospheric Measurements of Water Vapor by the JPL Laser Hygrometers

The concentration of water vapor in the upper troposphere and lower stratosphere has a significant impact on climate. Over the last sixteen years, the JPL Laser Hygrometers have collected a significant data record of atmospheric humidity from several platforms, including the NASA ER-2, WB-57, DC-8, and Global Hawk. Here, we describe the observed relation between atmospheric humidity and temperature in-cloud and out of cloud near the tropopause. We feature new measurements of water vapor from a substantially improved instrument made during the recent NASA SEAC4RS (Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys) field mission.