Relationships between Water Vapor and Liquid Water in Arctic Mixed-Phase Stratiform Clouds

The Arctic climate is warming more rapidly than any other on Earth through a process known as Arctic amplification. Arctic liquid-containing stratiform clouds may contribute to observed warming because they strongly influence the Arctic surface energy balance. However, to fully understand the role these clouds play in the warming Arctic, a more complete understanding of the temperature and moisture conditions necessary to form and maintain the clouds is required. In this study, a statistical analysis of these conditions within and surrounding single-layered, liquid-containing Arctic stratiform clouds is performed using radiosonde, microwave radiometer, ceilometer, and vertically pointing radar measurements made at Barrow, Alaska, USA (2002-2011), at Summit Station, Greenland (2010-2014), and at other Arctic remote-sensing observatories. Median average in-cloud specific humidities in Arctic single-layered, liquid-containing clouds at Barrow and at Summit are 2.2 g kg^-1 and 1.1 g kg^-1, respectively. Profiles of temperature, specific humidity, and relative humidity below, within, and above these Arctic stratiform clouds are summarized. Relationships between cloud liquid water path, a major modulator the clouds’ radiative influence, and other quantities, such as in-cloud precipitable water vapor and temperature are examined. Frequencies and distributions of temperature and specific humidity inversions within, above, and below the clouds are also investigated to learn about moisture sources to the clouds at each location. Statistical information provided in this study can be used in the production and verification of statistical and dynamical models of Arctic liquid-containing stratiform clouds and of the Arctic climate.