An evaluation of methods for determining during-storm precipitation phase and the rain/snow transition elevation at the surface in a mountain basin

Journal Article (Journal Article)

Determining surface precipitation phase is required to properly correct precipitation gage data for wind effects, to determine the hydrologic response to a precipitation event, and for hydrologic modeling when rain will be treated differently from snow. In this paper we present a comparison of several methods for determining precipitation phase using 12. years of hourly precipitation, weather and snow data from a long-term measurement site at Reynolds Mountain East (RME), a headwater catchment within the Reynolds Creek Experimental Watershed (RCEW), in the Owyhee Mountains of Idaho, USA. Methods are based on thresholds of (1) air temperature (T ) at 0. °C, (2) dual T threshold, -1 to 3. °C, (3) dewpoint temperature (T ) at 0. °C, and (4) wet bulb temperature (T ) at 0. °C. The comparison shows that at the RME Grove site, the dual threshold approach predicts too much snow, while T , T and T are generally similar predicting equivalent snow volumes over the 12. year-period indicating that during storms the cloud level is at or close to the surface at this location. To scale up the evaluation of these methods we evaluate them across a 380. m elevation range in RCEW during a large mixed-phase storm event. The event began as snow at all elevations and over the course of 4. h transitioned to rain at the lowest through highest elevations. Using 15-minute measurements of precipitation, changes in snow depth (z ), T , T and T , at seven sites through this elevation range, we found precipitation phase linked to the during-storm surface humidity. By measuring humidity along an elevation gradient during the storm we are able to track changes in T to reliably estimate precipitation phase and effectively track the elevation of the rain/snow transition during the event. © 2012. a a d w a d w s a d w d

Full Text

Duke Authors

Cited Authors

  • Marks, D; Winstral, A; Reba, M; Pomeroy, J; Kumar, M

Published Date

  • May 1, 2013

Published In

Volume / Issue

  • 55 /

Start / End Page

  • 98 - 110

International Standard Serial Number (ISSN)

  • 0309-1708

Digital Object Identifier (DOI)

  • 10.1016/j.advwatres.2012.11.012

Citation Source

  • Scopus