Recent modeling and observational studies make it increasingly clear that the polar regions play a disproportionately important role in governing the global climate system. Understanding the vertical temperature and moisture structure of the Arctic atmosphere is essential to understanding the dynamics and thermodynamics in the region. Several studies have demonstrated that vertical temperature gradients are important in estimating how surface temperature will respond to changes in greenhouse gas concentrations by virtue of the strong dependence of radiative fluxes on vertical temperature profiles [Sinha and Shine, 1994, Thuburn and Craig, 1997 and Gaffen et. al., 2000]

The development of the Global Positioning System (GPS) satellite network has provided an opportunity to acquire valuable new temperature, pressure and humidity data using radio occultation. The very cold lower stratosphere and upper troposphere in the polar regions represent near-ideal conditions for GPS observations, and the high density of profiles provide quantitative, high vertical resolution data with which to observe climate change. In this study, we aim to validate that GPS radio occultations do, in fact, provide a reliable measure of the state of the atmosphere in the Arctic by using Atmospheric Radiation Measurement Program observations from Barrow, Alaska and ECMWF Reanalysis .