Assessment of Alaska rain-on-snow events using dynamical downscaling

Journal of Applied Meteorology and Climatology
By: , and 



The ice formed by cold-season rainfall or rain on snow (ROS) has striking impacts on the economy and ecology of Alaska. An understanding of the atmospheric drivers of ROS events is required to better predict them and plan for environmental change. The spatially/temporally sparse network of stations in Alaska makes studying such events challenging, and gridded reanalysis or remote sensing products are necessary to fill the gaps. Recently developed dynamically downscaled climate data provide a new suite of high-resolution variables for investigating historical and projected ROS events across all of Alaska from 1979 to 2100. The dynamically downscaled reanalysis data of ERA-Interim replicated the seasonal patterns of ROS events but tended to produce more rain events than in station observations. However, dynamical downscaling reduced the bias toward more rain events in the coarse reanalysis. ROS occurred most frequently over southwestern and southern coastal regions. Extreme events with the heaviest rainfall generally coincided with anomalous high pressure centered to the south/southeast of the locations receiving the event and warm-air advection from the resulting southwesterly wind flow. ROS events were projected to increase in frequency overall and for extremes across most of the region but were expected to decline over southwestern/southern Alaska. Increases in frequency were projected as a result of more frequent winter rainfall, but the number of ROS events may ultimately decline in some areas as a result of temperatures rising above the freezing threshold. These projected changes in ROS can significantly affect wildlife, vegetation, and human activities across the Alaska landscape.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Assessment of Alaska rain-on-snow events using dynamical downscaling
Series title Journal of Applied Meteorology and Climatology
DOI 10.1175/JAMC-D-17-0276.1
Volume 57
Year Published 2018
Language English
Publisher American Meteorological Society
Contributing office(s) Coop Res Unit Seattle
Description 17 p.
First page 1847
Last page 1863
Country United States
State Alaska
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