The Arctic Radiation Measurement in Column Atmosphere-surface System (ARMCAS) was a collaborative research effort between the Cloud and Aerosol Research (CAR) Group, Department of Atmospheric Sciences, University of Washington (led by Professor Peter V. Hobbs) and Drs. Michael King and Si-Chee Tsay of NASA/Goddard. The field portion of ARMCAS was based out of Deadhorse, Alaska, from June 3-15, 1995. Flights of the University of Washington's Convair C-131A research aircraft and NASA's ER-2 aircraft took place over the tundra of the North Slope and over the partially ice-covered Beaufort Sea. Several of these flights were closely coordinated in order to provide simultaneous in situ and remote sensing measurements of arctic clouds.

The main goals of the C-131A flights in ARMCAS were:

- To measure the absorption of solar radiation by arctic stratus thick enough to be in the diffusion domain using the Cloud Absorption Radiometer aboard the C-131A and the technique described by King et al. (1990).

- To use the Cloud Absorption Radiometer to measure the albedo of various surfaces in the Arctic (tundra, sea ice, melting ice, refrozen ice, snow, etc.).

- To compare aerosol optical depths derived from in situ measurements of the aerosol light-scattering coefficient and from particle size distributions with those measured remotely by NASA/Goddard ground-based sun photometers.

- To measure vertical and horizontal profiles of aerosol properties, including size distributions, mass concentrations, particle humidification factors, cloud condensation nuclei, etc.

- To measure the microphysical properties (liquid water content, drop size distributions, droplet effective radius) over long path lengths in arctic stratus clouds to determine spatial and temporal variabilities.

- To obtain in situ measurements of cloud properties simultaneously with measurements from the ER-2 to determine whether remote sensing measurements can be used to derive cloud properties above a highly-reflecting ground surface (ice or snow) and in the presence of other cloud layers.

- As can be seen from the flight summaries given in the next section, and in more detail from the verbatim transcriptions of the voice tape recordings of crew members on each flight (Section 3), most of the objectives listed above were achieved.