Correction of raingages' snow undercatch at meteorological stations using data from snow surveys: an Armenian case study

The hydrological analysis of high elevation catchments is particularly difficult for two reasons:

. first, precipitation measurements are scarce at higher elevations,

. second, even when there are precipitation measurements, the collected amounts are strongly biased due to the well-known effect of wind on snowflakes.

Several formulations have been proposed to correct this wind-dependent underestimation of solid precipitation amounts. They all depend on at least one parameter, which must be calibrated for the specific location. At a few locations in the world, a double-fenced shielded raingage can be used to provide a reference precipitation amount, and the parameter of the correction can be determined experimentally. But at most locations, we have no real way to parameterize the adjustment relationship.

We use here a newly released dataset comprising 30 years of data for 11 stations located at high elevation in Armenia, where the precipitation gage network is strongly impacted by snow undercatch. Using ground snow surveys jointly with a degree-day based snow accumulation and melt model, we show that we can propose an adapted parameterization of the correction formula.