The Atmospheric Radiation Measurements (ARM) program: ARM's window on the Arctic

Abstract

A ‘blue ribbon’ committee established by the U.S. National Academy of Sciences has stated that uncertainties associated with cloud behavior constitute the major obstacle to progress in climate modeling and prediction. The Atmospheric Radiation Measurements (ARM) Program is a 10-year climate research program aimed at unravelling the role of clouds in the climate system. The focus is on studying the life cycle of clouds and the effects of clouds on high-latitude ARM site. Global climate models appear to be particularly sensitive to climate perturbations at high latitudes. Of course, climate changes have profound effects on the ecology. One objective is to design a research program that will enable us to investigate the relationship between arctic clouds and anthropogenic pollution transported to the north from lower latitudes. The Arctic is also characterized by extreme seasonal variation in insolation, surface properties, and exchange of water vapor between the surface and the atmosphere. This extreme variation leads to important climate feedback mechanisms involving the interaction between surface temperature and water vapor, cloud cover, and surface albedo. The challenge for the Alaskan ARM site is to capture these high-latitude feedback processes for inclusion in global climate models. To put possible climate changes into perspective, we note that the ‘Little Ice Age’, which ended the pre-Columbian Icelandic colony in Greenland and probably prevented permanent settlements in Vinland (i.e. North America), represented an average decrease of only about 2–3°C.