Retrospective forecasts of the upcoming winter season snow accumulation in the Inn headwaters (European Alps)

Abstract

Abstract. This article presents analyses of retrospective seasonal forecasts of snow accumulation. Re-forecasts with 4 months lead time from two coupled atmosphere–ocean general circulation models (NCEP CFSv2 and MetOffice GloSea5) drive the Alpine Water balance and Runoff Estimation model (AWARE) in order to predict mid-winter snow accumulation in the Inn headwaters. As the snowpack is a hydrological storage that evolves during the winter season, it is strongly dependent on precipitation totals of the previous months. Climate model (CM) predictions of precipitation totals integrated from November to February (NDJF) compare reasonably well with observations. This predictive skill is retained in subsequent water balance simulations when snow water equivalent (SWE) in February is considered. Given the AWARE simulations driven by observed meteorological fields as a benchmark for SWE analyses, the correlation achieved using GloSea5-AWARE SWE predictions is r = 0.57. The tendency of SWE anomalies (i.e. the sign of anomalies) is correctly predicted in 11 of 13 years. For CFSv2, the corresponding values are r = 0.28 and 7 of 13 years. The results suggest that some seasonal predictions may be capable of predicting tendencies of hydrological model storages in parts of Europe.

Decadal re-forecasts of glacier climatic mass balance

“…Comparing these 270 correlations to the low degree of correlation when simulating individual years emphasizes how the skill of our experiments lies primarily in simulating multi-annual averaged or cumulative mass balances, filtering out inter-annual noise. This is in line with similar approaches, where skill is found through integrating of fluxes over time, such as in seasonal snow accumulation (Förster et al, 2018).…”

ExtremA 2019

“…In den letzenJ ahren wurde sowohl die Rolle der zurückgehenden Gletscher im Wasserhaushalt insgesamt (Kuhn und Escher-Vetter, 2004;Koboltschnig und Schöner,2 011;V iviroli, 2011;N achtnebel et al,2 014;W eber et al,2 015), die Auswirkung der Änderung in der Schneebedeckung (Helfrichtetal.,2014(Helfrichtetal., , 2015Förster et al,2018) mit Mitteln der numerischen Modellierung untersucht. In Hochwasserprognosemodellen wird auch der glaziale Abfluss modelliert (Achleitner et al,2012;Schöber, 2014),wobei die Schneegrenze, Schneefallgrenzen und Sediment-sowieg eschiebetransportn ach wiev or Herausforderungen darstellen.…”