Workshop on Snow Data Assimilation
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Workshop on snow data assimilation Roland Koch and Marc Olefs Zentralanstalt für Meteorologie und Geodynamik (ZAMG), Vienna, Austria Impact of MODIS snow cover fraction on modeled SNOWGRID quantities Outline SNOWGRID Snow model Assimilation of MODIS fractional snow cover Impact of MODIS observation Validation Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany Snow depth variability (daily base) Seasonal (Nov–Apr) snow depth time series of stations elevated between 800 m and 1600 m 110 AT 90 70 50 30 NDJFMA snow depth [cm] 10 11–year low–pass (Gaussian) filtered 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 year 110 CH 90 70 50 Marty, C. (2008). Regime shift of snow days 30 NDJFMA snow depth [cm] in Switzerland, Geophys. Res. Lett., 35, 10 11–year low–pass (Gaussian) filtered L12501, doi:10.1029/2008GL033998. 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 year Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany SNOWGRID Snow model I Operational spatially distributed snow cover model with high spatial (100 m) and temporal (15 minutes time step) resolution for INCA-L grid (Zürich-Bratislava, Nürnberg-Triest) I Upper BC: Meteorological input from INCA (air temperature, rel. humidity, snowline (wet–bulb temp.), precipitation). Lower BC: INCA ground temperatures I Simple degree–day scheme I Simple 1–2 layer model I Snow settling (rapid setting after snowfall - destructive metamorphism, density-dependant slower settling thereafter (overburden pressure, metamorphism) I State variables are: snow depth (SD), snow water equivalent (SWE), average snow temperature (ST) Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany SNOWGRID model domain and topography Topography: 100 m DEM (corrected NASA SRTM3 + add. Data) 5°W 0° 5°E 10°E 15°E 20°E 25°E 30°E 55°N 50°N 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 3250 45°N 49°N 3000 2750 40°N 2500 2250 5°W 0° 5°E 10°E 15°E 20°E 25°E 30°E 48°N 2000 1750 1500 1250 topography [m] 47°N 1000 750 500 250 46°N 0 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany SNOWGRID products I Internal use (weather forecasts) I road weather products I Avalanche warning service I Wintertourism (websites) I snow melt runoff calculations I ... Olefs, M., Schöner, W., Suklitsch, M., Wittmann, C., Niedermoser, B., Neururer, A., Wurzer, A. (2013). SNOWGRID – A new operational snow cover model in Austria. International Snow Science Workshop Gre- noble, 2013. Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany Assimilation of MODIS fractional snow cover (FSC) initialize SNOWGRID I Experiment duration: model 01 Oct 2015 to 01 May 2016 I MODIS fields are interpolated onto SNOWGRID grid (nearest neighbour) model run I Nmax(MODIS) = 214 I 160 MODIS fields available 10UTC MODIS MODIS binary mask yes 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E modis 49°N model FSC yes model SD > 0 no 50 %≥ SD = 0 fsc>=50% 48°N update model update model fsc<50% 47°N SD = 0 m SD = 0.1 m ST = nan ST = -3 ◦C 2 2 SWE = 0 kgm− SWE = 150 kgm− 46°N masked 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 50 49°N Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany 25 48°N 5 47°N difference [cm] 5 46°N 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 25 Analysis departures (MODIS: passively assimilated) analysis departures: d = M(MODIS)pas − M 01 Okt 2015 10UTC 21 Okt 2015 10UTC 08 Jan 2016 10UTC 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 25 25 25 49°N 49°N 49°N 10 10 10 48°N 48°N 48°N 1 1 1 1 1 1 47°N 47°N 47°N 10 SH departures [cm] 10 SH departures [cm] 10 SH departures [cm] 46°N 46°N 25 46°N 25 25 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 22 Jan 2016 10UTC 13 Feb 2016 10UTC 17 Mar 2016 10UTC 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 25 25 25 49°N 49°N 49°N 10 10 10 48°N 48°N 48°N 1 1 1 1 1 1 47°N 47°N 47°N 10 SH departures [cm] 10 SH departures [cm] 10 SH departures [cm] 46°N 46°N 25 46°N 25 25 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany Analysis differences (MODIS: actively assimilated) analysis differences: a = M(MODIS)act − M 01 Nov 2015 00UTC 01 Dec 2015 00UTC 01 Jan 2016 00UTC 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 20 20 20 49°N 49°N 49°N 10 10 10 5 5 5 3 3 3 48°N 48°N 48°N 1 1 1 1 1 1 47°N 47°N 3 47°N 3 3 difference [cm] difference [cm] difference [cm] 5 5 5 10 10 10 46°N 46°N 20 46°N 20 20 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 01 Feb 2016 00UTC 01 Mar 2016 00UTC 01 Apr 2016 00UTC 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 20 20 20 49°N 49°N 49°N 10 10 10 5 5 5 3 3 3 48°N 48°N 48°N 1 1 1 1 1 1 47°N 47°N 3 47°N 3 3 difference [cm] difference [cm] difference [cm] 5 5 5 10 10 10 46°N 46°N 20 46°N 20 20 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany Available valid MODIS data at station location I Selection of 63 TAWES stations Station snow depth sensor: Laser distance sensor (Jenoptik SHM 30) 01 Oct 2015 to 01 May 2016 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E 70 49°N 60 50 48°N 40 30 47°N 20 10 MODIS availability [days] 46°N 0 9°E 10°E 11°E 12°E 13°E 14°E 15°E 16°E 17°E Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany Available valid MODIS data at station location II available valid MODIS OBS [days] Sonnblick Pitztaler Gletscher Galzig Schmittenhoehe Obergurgl Hahnenkamm/Ehrenbachhoehe Katschberg Loferer Alm Laterns Gapfohl Kanzelhoehe Hintertux im Zillertal Warth Schmirn Lech am Arlberg St.Jakob im Defereggen Brenner Kals Nauders St.Anton am Arlberg Stolzalpe Schroecken Langen am Arlberg Ramsau am Dachstein Mittelberg Seefeld Loibl Tunnel Holzgau Doellach St.Michael im Lungau Preitenegg Brand Krimml Neustift/Milders Saalbach Hochfilzen Bad Bleiberg Arriach Seckau Neumarkt Mariazell/St.Sebastian Koetschach-Mauthen Abtenau Obervellach Lienz Friesach Kirchdorf in Tirol Dellach im Drautal Allentsteig Rohrbach Koessen Hermagor Bischofshofen Krumbach in der Buckligen Welt Spittal an der Drau Mooslandl Bad Ischl Kufstein Bruck an der Mur St.Veit an der Glan Ferlach Graz Strassgang Deutschlandsberg Wien Hohe Warte 11033/11035 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 500 1500 2500 available MODIS obs [days] elev [m] Workshop on snow data assimilation March, 8/9, 2017, Offenbach, Germany Observations vs Control run vs.