Surface temperature adjustments to improve weather radar representation ofmulti-temporal winter precipitation accumulations

Hydrologists and water resources managers who work in areas that receive a significant portion of the annual precipitation in the form of snowfall rel y on good approximates of snow accumulation in order to assess snowpack vol umes for snowmelt streamflow estimation. Weather radar rainfall estimation has been used for hydrological modelling and radar has been used for the es timation of snowfall from individual events, yet radar has rarely been used to measure snowfall accumulation over time periods longer. Snowfall estima tes for weekly, monthly, and seasonal accumulation periods have been compar ed to measured Nipher-shielded Belfort precipitation gauge quantities. A lo cal scaling issue that caused overestimates is discussed. To enhance the ac cumulation estimates, the conventional scan radar images were adjusted usin g the near surface air temperatures. The adjustment for mixed precipitation improved the accumulation estimates, while the subsequent particle shape a djustment for snow crystal shape did not further enhance the radar estimate s. (C) 2001 Elsevier Science B.V. All rights reserved.