Use and interpretation of ECMWF products 05 09

Use and interpretation of ECMWF products 05. -09. 02. 2018, Reading, The United Kingdom Use of ECMWF products in Hydrological Forecasts System in Latvia Andrejs Zubaničs Latvian Environment, Geology and Meteorology Centre, 165 Maskavas Street, Riga, LV-1019, e-mail andrejs. zubanics@lvgmc. lv Heavy and intensive precipitation over Eastern part of Latvia 23 – 24 August 2017 Service main tasks Ø development of environmental monitoring system Ø assessment of environmental quality and natural resources Ø management of environmental data Ø report on environment quality, meteorological, hydrological phenomena, warnings of dangerous and natural disasters, weather and hydrological forecasting Ø environment laboratory testing Ø maintenance of GHG emissions trading national scheme What was coming. . . ? Ø supervision of subsoil resources and insurance of rational subsoil use Aviation Forecasting division 8 Synoptics Forecasting Hydrometeorological and Climate forecasting division Department 4 Hydrologists Climate and Methodological Division Fig. 2. EUMETSAT satellite image Europe 23. 08. 13 UTC and Latvia 24. 08. 10 UTC What was expected ? . . . weather and hydrological forecasts 23. 08. 00 UTC 22. 08. 12 UTC Hydrological forecasts with HBV model ü Every day - daily mean discharge 10 days forecast to Pļaviņas hydropowerplant ü Two times in a week - daily mean river discharge forecast for 4 Latvian river catcments including Pļaviņas hydropowerplant ü Seasonal forecast Fig. 3. ECMWF HRES – total amount of precipitation for period 23. 08 morning – 24. 08. evening WSFS – Water Simulation Forecast System Included three of the largest river catchments in Latvia. Data for system set up • Historical hydrometeorological observation for up to 100 years long • Operational hydrometeorological observations • ECMWF and LEGMC weather forecasts Forecasted parameters • Water level, discharge, runoff and temperature • Air temperature • Precipiation • Evaporation • Snow cover and water equivalent • Storages Forecast time • Forecasts every day are calculated five times for 14 days, 3 months and seasonal for one year. A On August 22 nd cyclone developed over the territory of Ukraine, streching from the Black Sea to the Baltic Sea. The Cyclon moved to the north dirrection and brought wide zone of clouds and intensive precipitation to the eastern part of Latvia. Rainfall started on evening of August 23 rd and precipitation zone left rerritory of Latvina only on late evening of August 24 th. Over 24 hour period on the eastern part of Latvia amount of precipiation reached 50 -135 mm. Weather forecasts It was expected that total amout of precipitation in 24 hours will reach up to 20 -70 mm, but on 23 rd of August up to 100 mm on the most eastern part of Latvia. Also strong wind gusts were forecasted up to 19 m/s. Hydrological forecasts From hydrological forecasts it was expected flash-floods with water level increase in rivers by 1 -3 m reaching maksimum water levels 1 -4 days after the precipitation, depending on location and catchment characteristics. 1 2 Fig. 4. Latvian WSFS medium-range water level forecasts for river points Vaidava – Ape (1) and Tirza – Lejasciems (2) on dates 23, 25 – 27 August, 2017. What did we get ? . . . observed amount of precipitation and water levels in rivers B Observed total amount of precipitation 23 – 24. 08 06 UTC C Fig. 1. River catchments included in WSFS (A) D and examples of 14 days (B), 3 month (C) and 1 year (D) water level forecasts Use of ECMWF products HBV model setup Because of HBV model set up it uses daily mean values of meterological and hydrological parameters. In the model setup two ECMWF products are being used: ü mean of 51 ECMWF 2 m temperature forecasts ansambles ü Daily precipitation sum from ECMWF control forecast WSFS forecast system uses precipitation and air temperature forecasts: ü 50+1 ansambles with 16 x 16 km resolution ü ECMWF official HRES forecast 9 x 9 km resolution ü Official LEGMC forecast (edited ECMWF HRES) 7 -9 km resolution Amount of precipiation 23. 08. 06 UTC - 24. 08. 10 UTC Proportion of Proportion Amount of Norm for last 10 Norm for months last 10 of monthly precipitation days of month August days norm (%) 134, 8 21, 6 69 624 195 Rēzekne 79, 8 28, 5 73, 8 280 108 Daugavpils 76, 1 24, 2 60, 2 314 126 Piedruja 58 29, 6 68, 1 196 85 Sīļi 48, 9 24, 3 75, 2 201 65 Gulbene 42, 1 26, 1 79, 2 161 53 Zīlāni 41, 4 33, 9 91, 2 122 45 Alūksne 37, 9 34, 9 80, 2 109 47 Zosēni 28, 5 27, 7 69, 1 103 41 Lubāna 13, 7 32, 4 78, 4 42 17 Skrīveri 11, 7 33, 8 81, 6 35 14 Priekuļi more than monthly norm more than months last 10 days norm How did it look from space. . . ?