RESEARCH HIGHLIGHT

Northern Alaska Connections I:  Measuring Solid Precipitation

November 16, 2007

The North Slope region of Alaska is home to abundant wildlife and Iñupiat Eskimos and has become one of the largest oil producing areas in the nation.  It is also a region especially sensitive to changes in climate. Environmental monitoring and research have become priorities for this area because in the Arctic climate change is amplified, directly affecting human communities and activities, and the ecology of the region.   The International Arctic Research Center has become increasingly involved in research on the North Slope to help assess and understand specific environmental changes.  We are partnering with a number of other institutions and our researchers are investigating a wide variety of issues including wetland hydrology, biochemical feedbacks, precipitation, sea-ice trends, severe weather activity, and terrestrial carbon balance.  We also conduct summer schools and community-based transformative education/outreach efforts across northern Alaska. 

This is the first in a series of research highlights on IARC research and educational efforts in Northern Alaska.  Our focus today is on solid precipitation research.

In climate physics, snow is influential due to its high-reflectivity, ground-insulating properties, and contribution to surface hydrology. Ground-based measurements of snow accumulation are needed both to improve understanding of surface-atmosphere exchange processes and to provide a testing mechanism for remote-sensing techniques.  Accuracy in measuring solid precipitation is important for climate research, hydrological and meteorological applications, and ecological research.  Winter precipitation monitoring is also crucial for transportation and water resource planning throughout Alaska and other cold regions where snow is present for up to nine months each year.

Snow covered area can be measured through remote sensing using data in the visible spectrum, but snowfall, snow depth, and snow water equivalent are difficult to obtain remotely. Manual snow surveys are relatively accurate, but impractical for most areas due to their high cost. Most automated weather stations depend on some sort of precipitation gage. Unfortunately, gages measure snow very poorly, particularly in windy conditions. They also have frequent mechanical failures. These problems are most serious in the Arctic, where most precipitation falls as snow and automated weather stations may go unchecked for months at a time.

Jessie Cherry, an Arctic Region Supercomputing Center post-doctoral fellow at IARC, is working on measuring snowfall near Barrow, Alaska.  The project is a contract through the Department of Energy to study the performance of the Total Precipitation Sensor (TPS) for the Atmospheric Radiation Measurement (ARM) project.  Mark Ivey from Sandia National Laboratories is serving as the co-mentor for the TPS and Dr. Cherry’s primary collaborator.  This experimental sensor measures both rain and snowfall and is designed to overcome some of the biases associated with gage measurement of solid precipitation.

This work is in collaboration with Matt Sturm and Tom Douglas of the U.S. Army Cold Regions Research and Engineering Laboratory, and Sveta Berezovskaya, Daqing Yang, and Doug Kane of the University of Alaska Fairbanks.  Funding for these investigators comes through an International Polar Year initiative to build a state-of-the-art snow observing system for the Arctic Observing Network program at the National Science Foundation.

Publications

Cherry, J.E., L.-B. Tremblay, M. Stieglitz, G. Gong, S. Déry (2007) Development of the Pan- Arctic Snowfall Reconstruction: new land-based solid precipitation estimates for 1940-1999, Journal of Hydrometeorology, in press.  Download PDF: https://people.iarc.uaf.edu/~jcherry/documents/jcherry_JHM_final_package.pdf

Cherry, J., B. Tremblay, S. Déry, M. Stieglitz (2005) Solid precipitation reconstruction using snow depth measurements and a land surface hydrology model, Water Resour. Res,  41:9, W09401, doi:10.1029/2005WR003965.  Download PDF: https://people.iarc.uaf.edu/~jcherry/documents/2005WR003965.pdf

Photos

Snow normally begins falling in Barrow in September and stays on the ground until June. 

Snow falling on the tundra.