<Operational nowcasting systems in the framework of the 4-D MeteoCube>

Transcription

1 <Operational nowcasting systems in the framework of the 4-D MeteoCube> <Dr. Tatiana Bazlova, Dr. N.Bocharnikov, Pr. A. Solonin> <Institute of Radar Meteorology - IRAM>

2 Background Nowcasting is applicable for meteorological providing of aviation, highways, cities, and special events like Olympic Games. Nowcasting systems MeteoTrassa and MeteoExpert have been developed at IRAM and implemented with the aim to support road authorities for decision making in winter weather situations, to provide useful information for forecasters and decisionmakers of Olympic Games and University Games, to give relevant information support to aviation forecasters, airdrome maintenance service and decisionmakers.

3 Background The MeteoTrassa has been operational since 2011 at the Ring Highway around St. Petersburg, and since 2016 at the Western High-Speed Diameter in St. Petersburg. The MeteoExpert was one of the six nowcasting systems of the FROST-2014 (WMO WWRP) and was operational at the Main Operations Center of Sochi-2014 Olympic Games. The nowcasting systems of IRAM operate 24/7 for over 3 years at 2 airports - Irkutsk and Pulkovo - and provide location-specific forecasts of aviation high impact weather with lead time of 4-6 h and update cycle of 10 min. The systems performance is discussed in this presentation.

4 Pulkovo and Irkutsk

5 Method A methodology of nowcasting is based on local observations, an adaptive assimilation scheme, and numerical ABL model. All available data sources can be used including the following: aviation weather observation station (AWOS), automatic weather station (AWS), weather Doppler radar, temperature profiler, road/runway weather station (RWS), AMDAR, and satellite. Radar data mosaics is useful source of information about the location of precipitation. Dual polarized data are used to derive weather radar products. A real-time radar based algorithm has been developed to nowcast precipitation incl. its rate and type at res of 1 km in space and 10 min in time. A combination of a cross - correlation tracking method, averaged Doppler velocity, and prognostic wind (at a level of 700 hpa) is employed.

6 Model The 1D ABL model is designed to represent the evolution of vertical profiles in the lower atmosphere. The momentum, water conservation and thermodynamic equations in terms of wind components, specific humidity, and potential temperature are written in the standard form. The k-ɛ turbulence closure scheme is used which is based on the prognostic equations for TKE and EDR. The surface temperature is modeled with a force-restore equation, where the soil flux at the surface is given by the surface energy balance. The lower BC is formulated with the aid of the similarity theory. The upper BC is set in accordance with GRIB-coded data from NWP model. Measurement data are used to set as IC. The model provide fast and stable calculations which are required for operational use.

7 Outputs Location-specific forecasts for points where AWOS/AWSs exist, with lead time of 4-6 hours, updated every 10 min. Surface temperature and vertical profiles of air temperature, wind speed and wind direction, dew point temperature, turbulence kinetic energy, and eddy dissipation rate. Precipitation onset, type and rate Ceiling (cloud base height) Visibility (parameterization in terms of air temperature, relative humidity, precipitation type and rate) Ice formation on the runway

8 Irkutsk airport Operations at Irkutsk airport are significantly impacted by low visibility caused by fog. The MeteoExpert has been implemented at the airport since August 2014 to provide 6-h forecasts of weather conditions incl. visibility. Data input is used from AWOS (1 min) and 3 additional AWSs (10 min). Additional AWSs have been installed at fogging sites in the vicinity of the airdrome (radius of ~5 km) for anticipating advection fog. Forecasts for 4 locations and common forecast for the runway are generated.

9 Pulkovo airport More detail information is required in order to ensure the effective maintenance in winter (to keep runways, taxiways and stands free of snow and ice) and to improve the airport safety and capacity. The MeteoTrassa has been installed in 2014 to provide the airdrome service with a vital data for its maintenance. Particular emphasis is placed on the information on runway icing and the onset of precipitation. Measurement data and 4-h forecasts incl. ice on the surface and precipitation are provided. This information helps airdrome service to react to hazardous weather in time and to initiate preventive works. Next installation of the MeteoExpert nowcasting system is started at Pulkovo in Nov It is planned to be operational since 2018 to provide 4-h forecasts of visibility and ceiling which are the most critical parameters for the airport operation.

10 The 4-D MeteoCube Observations and forecasts are visualized on screens of workstations and the MeteoCube website. The 4-D MeteoCube was designed at IRAM in accordance with the ASBU concept of the 4-D database of MET information as the best choice to ensure that accurate and timely weather data would be integrated into operational decision making. The MeteoCube contains continuously updated weather observations (standard and non-standard data, ex. data from RWS), high resolution forecasts (conventional data from NWP models), and observations and forecasts of parameters relevant to aviation (convection, ceiling and visibility, runway icing). Quality control algorithms are applied to ensure the correct output.

11 Tabular, graph and map data displays on WSs and the MeteoCube website Temperature profiles Fog forecast Low ceiling forecast Low visibility forecast

12 Displays of recent, current and forecast weather Regular forecast Current weather& forecasts for runways Runway sensors Surface conditions Precipitation nowcast

13 Weather radar mosaic & wind vectors help visualize forthcoming weather

14 Verification Forecasts have been verified against actual observations at 10-min intervals. Criteria of accuracy correspond to Annex 3 ICAO. Verification shows the reasonable accuracy of visibility forecast and the gradual increase of accuracy for the operation period over PC- Proportion Correct F - False alarm rate H - Hit rate Miss - Miss frequency ORSS- Odds Ratio Skill Score EDI - Extremal Dependency Index SEDI - Symmetrical Extremal Dependency Index

15 Verification facilitates improvements Accuracy of fog onset time 6-h forecast has been calculated for 9 months of 2017: standard deviation = 26 min, and mean error = 2 min. Accuracy of precipitation onset time 2-h forecasts has been calculated for summer 2017: standard deviation = 12 min, and mean error = -3 min. Percentage Correct of 4-h forecasts of runway icing = 92%. To improve the quality and the usage of the forecasts, the data processing algorithms are constantly under development based on the verification and user s feedback.

16 Conclusion The nowcasting system is specifically tailored to the airport needs. Impact weather parameters are to be taken into account which are most critical for the airport. Based on the verification it can be concluded that the nowcasting systems MeteoExpert and MeteoTrassa give real support to aviation forecasters, airdrome maintenance service and decision-makers at the airports. Installation of the nowcasting system is first stage of its implementation. Further the system has to be developed, subject to verification and user s feedback. Development of the system is the process of making algorithms gradually better, and technical component more diverse and advanced. New MET information about high impact weather can be translated into the ATM systems for decision-making by means of the MeteoServer (the IRAM s system to provide ATM with MET data, > 40 systems in 6 countries)

17 T. Bazlova, N. Bocharnikov, A. Pugachev, M. Vinogradov and A. Solonin. Usage of RWIS MeteoTrassa in the ITS. SIRWEC 2014 proceedings D. Kiktev et al. FROST-2014: The Sochi Winter Olympics International Project. Bull. Amer. Meteor. Soc., 2017, doi: /BAMS-D T. Bazlova. Weather stations for Sochi Meteorol. Technology International, , Thank you T. Bazlova, N. Bocharnikov, A. Solonin. The MeteoExpert system of IRAM. 1st European Nowcasting Conference, May 2014, Vienna, Austria T. Bazlova, N. Bocharnikov, A. Solonin. Nowcasting system MeteoExpert Geophys Research Abstr. Vol. 18, EGU , 2016, EGU General Assembly T. Bazlova, N. Bocharnikov. Verification of the MeteoExpert nowcasts. Universal Journal of Geoscience 5(1): 1-9, DOI: /UJG Zilitinkevich S.S., Esau I.N. Similarity theory and calculation of turbulent fluxes at the surface for the stably... Boundary-Layer Meteorol V P ICAO Annex 3 to the Convention on International Civil Aviation I. T. Jolliffe, I.T., D.B. Stephenson (eds.). Forecast Verification: England, C. A. T. Ferro, D.B. Stephenson. Extremal Dependence Indices: improved verification measures for deterministic... Wea. Forecasting, 26, , 2011.