Item: Towards a High-Resolution Operational Forecasting Tool for the Southern Alps – New Zealand
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Title: Towards a High-Resolution Operational Forecasting Tool for the Southern Alps – New Zealand
Proceedings: International Snow Science Workshop 2014 Proceedings, Banff, Canada
Authors:
- Sascha Bellaire [ Institute of Meteorology and Geophysics, University of Innsbruck, Tyrol, Austria, Innsbruck, Austria ]
- Marwan Katurji [ Center of Atmospheric Research, Dept. of Geography, University of Canterbury, Canterbury, New Zealand ]
- Tobias Schulmann [ Center of Atmospheric Research, Dept. of Geography, University of Canterbury, Canterbury, New Zealand ]
- Andrew Hobman [ New Zealand Mountain Safety Council, Christchurch, New Zealand ]
Date: 2014-09-29
Abstract: The Southern Alps of New Zealand are located in an extreme maritime climate with high precipitation amounts and strong winds causing heavy winter storms with exceptional deposition. In addition, frequent rain-on-snow events can cause widespread avalanching making avalanche warning a challenging task. This study aims to provide decision support for avalanche forecasters by coupling a snow cover model (SNOWPACK) with a numerical weather prediction model (NWP). The open-source Advanced Regional Prediction System (ARPS) is well suited for small-scale (sub-kilometer) weather dynamics and was used in this study. As a proof of concept ARPS simulations were performed with a horizontal resolution of 3 km as well as 1 km for a period of 10 days between July 4 and July 13, 2013 for the Craigieburn Range area. During this period about 50 cm of new snow were observed at Porters Ski Area, whereas the vast amount (~38 cm) was related to a single storm on July 6, 2013. Results show that at least a 1 km horizontal resolution was required to simulate this particular event and the resulting precipitation amounts. By forcing the Swiss snow cover model SNOWPACK with the ARPS forecasted data – on a 1 km grid – we were able to simulate the 24-hour new snow amounts during this period with fair accuracy while using fixed densities for new snow between 50 kg m-3 and 75 kg m-3. Although more investigation and simulations for a longer period are required we believe that this initial study, proposing a coupling between ARPS and SNOWPACK, shows promising potential to become an operational forecasting tool for New Zealand's warnings services.
Object ID: ISSW14_paper_P1.01.pdf
Language of Article: English
Presenter(s):
Keywords: Southern Alps, ARPS, SNOWPACK, snow cover simulation, decision making
Page Number(s): 427-432
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