The DOE's Atmospheric Radiation Measurement Program seeks to better understand earth radiation field/cloud interactions by studying these processes at intensively instrumented cloud and radiation testbed sites.   Sandia's three key roles in these activities are described below.

Development and Monitoring of New Instruments

The cloud and radiation testbed sites are climate observatories.  As such, they require highly sophisticated instrumentation that can operate in the field around the clock all year with minimal operator attention.  Water vapor plays a key role in cloud formation and in propagation of the earth's thermal energy through the atmosphere, but existing instrumentation lacks the vertical and temporal resolution required to provide detailed water vapor profiles.  Over the past several years, we have developed the next generation of a laser remote-sensing technique (raman light detecting and ranging [lidar]) for providing high-vertical-resolution water vapor profiles during both night and day.  We successfully placed this system in a fully automated field unit at the Oklahoma cloud and radiation testbed site.  We are working to field two other sophisticated measurement systems as part of the suite of cloud and radiation testbed instrumentation.  The first involves the site integration, algorithm development, and data handling of wide-field-of-view cameras developed by the Scripp's Institute for measuring cloud distributions in the sky.  The second involves highly accurate radiometers developed by the National Aeronautics and Space Administration and the Scripp's Institute to measure solar flux.

Development of Portable Measurements Stations

Although the Oklahoma cloud and radiation testbed site has a large suite of individually emplaced instruments, succeeding sites will use a set of instruments in a self-contained, easily transportable vessel.  These self-contained sets of instruments (known as atmospheric radiation and cloud stations) make possible the placement of both tropical and Alaskan cloud and radiation testbed sites, despite reduced budgets.  As the field integration manager for the radiation and cloud stations, Sandia led a multilaboratory team in designing, constructing, and testing the system, which provides power, a full suite of instruments, data handling, and work space. The first atmospheric radiation and cloud station (ARCS) was successfully placed on the island of Manus in Papua, New Guinea and marked the opening of the tropical western Pacific atmospheric radiation measurement site.  A second ARCS (Nauru99), to be placed on Nauru, is a critical element of the intensive operating period experiment.  Sandia is also testing a third ARCS, which may be placed on Kiritimati (Christmas Island), Kwajalein, or the Maldive Islands.  In addition, modified polar ARCSs have been deployed on the North Slope of Alaska.

Site Manager for the North Slope of Alaska
Cloud and Radiation Testbed Site

Our site on the North Slope of Alaska began operating in 1997.  At present, this site consists of a long-terrn facility at Point Barrow at the northernmost tip of Alaska.  We also recently deployed a complementary instrument suite aboard an ice-breaker circling the Arctic Ocean in the Arctic gyre.  The North Slope of Alaska and adjacent Arctic Ocean locales were chosen because the polar region is the heat sink in the world's climate and because the pole has extremes of insolation (six months of day and six months of night), humidity (wet summers and dry winters), and surface albedo (highly reflective snow that melts).  These extremes provide a stringent test of the understanding of the earth's radiation/cloud interactions.  Sandia is responsible for planning, implementation, and operation and works closely with scientists at the University of Alaska to formulate the science plans and coordinate the atmospheric radiation measurement program with other research activities in arctic environments, especially the National Science Foundation's Surface Heat Budget of the Arctic Program.