The Evaluation of the Heavy Convective Precipitation Forecast

The thesis deal with the evaluation of the quantitative convective precipitation forecast and its uncertainty. Five convective events that produced heavy local rainfall in the Czech Republic were studied. The nonhydrostatic local model LM COSMO was run with a horizontal resolution of 2.8 km and an ensemble of 13 forecasts was created by modifying the initial and boundary conditions. Forecasts were verified by gauge-adjusted radar-based rainfalls. Ensemble skill and ensemble spread were determined using the Fractions Skill Score (FSS). The spread represents the differences between the control forecast and the forecasts provided by each ensemble member, while the skill evaluates the difference between the precipitation forecast and radar-based rainfalls. The numerical experiments used the FSS-skill and spread values related to four events to estimate the skill-spread relationship. The relationship was applied to a fifth event to estimate the QPF ensemble skill given the ensemble FSS-spread. A couple of test of FSS computing were performed. The analysis of these events proved, that the application of the new fuzzy verification scores in high resolution QPF is highly advisable. The new scores are more suitable then the traditional verification scores based on the contingency table. In order to asses the..

Diagnostic and prognostic precursors withholding convection

Department of Atmospheric PhysicsKatedra fyziky atmosféryFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

Diagnostic and prognostic precursors withholding convection

Department of Atmospheric PhysicsKatedra fyziky atmosféryFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

Vyhodnocení nejistoty plošné předpovědi silných konvektivních srážek

Extreme convective events have been studied with numerical weather prediction model LM COSMO (horizontal resolution of 2.8km) and radar data. An ensemble of 13 forecasts, which followed from modyfying initial fields, was created for two of analyzed events. Uncertainty in area-related quantitative precipitation forecast (QPF) was evaluated by fraction skill score (FSS) to quantify an ensemble spread and skill. The spread assesses a difference between a control forecast and ensemble member forecasts and the skill evaluates a difference between a precipitation forecast and radar derived precipitation. The uncertainty analysis shows an effect of forecast lead time and space scale as well as a sensitivity to the area structure of precipitation field. In this paper we summarize our first results dealing with the scale influence on the ensemble spread and skill

Precipitation by PERUN

Weather reanalyses are a powerful tool for studying historical weather both at individual points and especially over an area. The detailed reanalysis produced by the PERUN project thus makes it possible to reveal various aspects of the atmosphere to a degree that we are unable to achieve with measurements. Since it is still a model approximation, it is of course necessary to detect systematic biases by verification before its use. Climate model runs, on the other hand, can uncover the future evolution of the atmosphere. Since these calculations cannot yet be verified, it is necessary to validate a historical run of the same model and subtract the revealed systematic errors from the future projections. In the PERUN project, both the historical run and two climate runs up to 2100 have been calculated. In this work, we present a basic verification and validation of the precipitation forecasts and an evaluation of the separation of precipitation into stratiform and convective precipitation and, in addition, into\nliquid and solid precipitation

Characteristics of convective environment in ALADIN reanalysis

For the prediction and assessment of the potential for convective cloud formation, various characteristics of the convective environment are used. Values of CAPE, CIN, wind speed, and temperature at several standard levels are available from the ALADIN reanalysis outputs, from which wind shear and vertical temperature gradient can be calculated. Verification allows for point comparison with data from sounding measurements, for example, from Prague, Libuš

History of the Milešovka observatory

The mountain station, ie a station with an altitude above 500 m, with the longest continuous series of measurements in our territory\nis the meteorological station on Milesovka mountain. The station began its activity on January 1, 1905, and the length of its measurement\nis one of the longest serving mountain stations not only in our country but also in the world. The unique location of Milešovka Station is its location\non top of a conical mountain at an altitude of 837 m. This unique location is a prerequisite for the\nhave a similar character to the ambient atmosphere

Verifikace kvantitativní předpovědi srážek

13314

Srovnání účinnosti diagnostických a prognostických charakteristik konvekčního prostředí

657