An objective snow profile comparison method and its application to SNOWPACK

Citation
M. Lehning et al., An objective snow profile comparison method and its application to SNOWPACK, COLD REG SC, 33(2-3), 2001, pp. 253-261
Citations number
3
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Civil Engineering
Journal title
COLD REGIONS SCIENCE AND TECHNOLOGY
ISSN journal
0165-232X → ACNP
Volume
33
Issue
2-3
Year of publication
2001
Pages
253 - 261
Database
ISI
SICI code
0165-232X(200112)33:2-3<253:AOSPCM>2.0.ZU;2-H
Abstract
With the increasing use of numerical models predicting the snow cover statu s, the need for a simple and standardized evaluation procedure arises. We p resent such a method that compares numerical model profiles with snow pit p rofiles and provides a quantitative statistical agreement-disagreement meas ure. The method can also be used to compare several model profiles with eac h other. The first step of the method is the mapping of the model profile layers ont o the layers of the observed profile. This mapping is necessary to adjust f or deviating total snow depth and shifted positions of the layers. Followin g the mapping, the individual profile parameters such as grain type, grain size, liquid water content, temperature and density are compared. The resul t of the comparison is a score between 0 (profiles show no agreement) and 1 (profiles are identical) for each parameter. The parameter scores can be c ombined to give an overall profile score between 0 and 1. The method facili tates evaluation studies and allows to quantify improvements made in the mo deling of processes in the snow cover. This is illustrated by analyzing a simulated profile at an IMIS (German: In terkantonales Mess-und Informations System) automatic snow and weather stat ion with an observed, detailed snow pit profiles from the Swiss Alps. The a greement score for the parameter grain type increased from 0.3 to 0.7 after introducing an additional grain type in the simulation. In addition, the s cores were calculated for two observation stations in the Swiss Alps for a whole winter season and it was detected that for most of the winter an over all agreement score between SNOWPACK simulation and snow pit profile of app roximately 0.8 is reached. The temperature regime is modeled best and most difficulties are encountered with grain type. An important result is furthe r that the energy balance processes at the beginning of the spring melt sea son has to be improved. (C) 2001 Elsevier Science B.V. All rights reserved.