ESRL Global Systems Division
Alaska's Recent Heavy Snowfall Affects Profiler Wind Measurements
The Forecast Systems Laboratory operates and maintains the NOAA Profiler Network (NPN) in coordination with the National Weather Service. The NPN provides continuous real-time measurements of upper-air winds (and other meteorological data) to the NWS and other users from 32 stations in the central U.S. and 3 in Alaska. The NPN wind profilers are designed to operate unattended and provide wind data during nearly all weather conditions, including heavy rain and snow. This has been the case in the lower 48 states, but recent above-normal snowfall in Alaska caused significant loss of height coverage from the profiler site at Talkeetna, Alaska, about 90 miles north of Anchorage.
Studies by scientists in the FSL Demonstration Division show that snowfall accumulation on the profiler's antenna, a large horizontal metal grid, is not a problem until it reaches about two feet high, and particularly if it contains layers of snow and ice. With the total seasonal snowfall in the Anchorage area 30% above average this year, the Talkeetna profiler recently showed errant or no data for higher levels of the atmosphere. Doug van de Kamp, Chief of Profiler Network Operations, plotted the wind data from that profiler for one week to show the impact of the snow and ice on the antenna, and the restoration of normal height coverage following snow removal.
Talkeetna, AK winds before and after snow removal
(Time goes from right to left)
So, what procedure is taken to restore profiler operations at such a remote location? Two very fit electronics technicians are assigned from either the Anchorage or Fairbanks NWS offices to remove snow and ice from the profiler antenna. The task is quite arduous no matter the process: either covering the antenna with tarps and melting the snow with propane-fueled heaters, or shoveling the snow off the grid, which is about 6 feet above the ground at Talkeetna. The technicians opted to shovel in this case. Their bonus inspiration came from the beautiful scenery and entertainment from a moose who was interested in the whole operation.
NWS field engineer working to remove the snow from the antenna
Profiler antenna snow removal completed
Curious local Alaskan wildlife
The impact of significant snow accumulation on the antennas will be addressed in future profiler designs. The Alaska profilers help forecasters to monitor changes in upper wind strength and direction, and play a key role in predicting the intensity and cessation of snowstorms, as well as dispersion of ash during volcano eruptions.
Name: Doug van de Kamp