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Evaluation of precipitation totals simulated by the ALADIN/PERUN atmospheric reanalysis at high spatial resolution
Bližňák, Vojtěch ; Zacharov, Petr, jr.
Atmospheric reanalyses represent powerful tools for obtaining information about the state of the atmosphere in history, which is obtained by numerical weather prediction (NWP) models whose predictions may (but may not) be improved through the assimilation of measured data. Significant developments in computer technology have recently enabled to increase their spatial resolution so that even meteorological phenomena of a local nature can be better captured. However, most NWP models compensate this capability by reducing the computational domain, which largely limits the use of these forecasts for the following meteorological, climatological and/or hydrological applications. The newly developed ALADIN/PERUN atmospheric reanalysis provides simulations of various meteorological variables at high spatial (2.3 km) and temporal (1 h) resolution over most of Europe between 1989 and 2020. Due to the high resolution of the reanalysed data, it can be expected that precipitation fields will capture local-scale processes well, and thus reproduce more faithfully, for example, heavy convective precipitation. The presented paper aims to evaluate this capability based on gauge-adjusted radar estimates of precipitation totals during warm parts of the year when strong convective but also stratiform precipitation occurs in Central Europe. The accuracy of the localization and precipitation sums will be evaluated for two different runs of the NWP model. The first one (ALADIN/Reanalysis) involves a complete assimilation of the observed data every 6 hours using a 4D-VAR assimilation scheme. The second (ALADIN/Evaluation Run) uses only the boundary conditions from the ERA-5 global reanalysis and the calculation of the forecasts is not further modified based on measured data. Comparing the two runs will provide us with information about the level of physical description in the NWP model as well as the effect of assimilation on the resulting precipitation fields. In addition, the paper is unique in that it will use detailed fields of 'observed' precipitation totals at high spatial resolution, which conventional rain gauge data cannot offer.\n
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Validation of reanalysis for Central Europe PERUN/Reanalysis
Beranová, Romana ; Rulfová, Zuzana ; Sokol, Zbyněk
PERUN/Reanalysis is based on the ALADIN numerical forecast model, which has been adapted for climatological calculations. To serve as one of the reference sets for estimating expected climate changes in the coming decades, it needs to undergo validation against station measurements and possibly against other commonly used data sets. In this conference paper, we will examine the validation of basic meteorological quantities across the computational domain of the ALADIN model. To achieve this, we will use station data from the ECA&D database, station data in the regular network (Eobs), and the ERA5 global reanalysis. Validation will be conducted for the period from 1990 to 2014. During validation, our primary focus will be on air temperature (minimum, maximum, and mean) and precipitation. We will also examine additional variables, including wind speed.\n
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Lightning activity prediction using a numerical weather prediction model
Uhlířová, Iva ; Popová, Jana (advisor) ; Zacharov, Petr (referee)
Lightning activity is considered a severe meteorological hazard that needs to be studied, monitored as well as predicted. This thesis focuses on the prediction of lightning activity by the Lightning Potential Index (LPI) in the COSMO numerical weather prediction (NWP) model that comprises 1- and 2-moment (1M and 2M, respectively) cloud microphysical schemes. The objective of this thesis is to investigate the correlation between the predicted lightning activity and the detected one (by the European network for lightning detection EUCLID). Events of the years 2018 and 2019 that recorded significant lightning activity over Czechia are considered for the analyses. For the first time over Czech region, the prognostic values of LPI calculated for each event are verified. In particular, the spatio- temporal distribution of the predicted vs. detected lightning activity is evaluated. Both spatial characterizations and diurnal course of detected lightning activity correspond well to the theoretical knowledge. Thus, spatial (horizontal) and temporal approaches are applied to verify the lightning activity prediction. The results of this thesis successfully verify the LPI prognostic values both in space by comparing the LPI values with the proximity of detected lightning flashes, and in time by contrasting the...
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Lightning activity prediction using a numerical weather prediction model
Uhlířová, Iva ; Popová, Jana (advisor) ; Zacharov, Petr (referee)
Lightning activity is considered a severe meteorological hazard that needs to be studied, monitored as well as predicted. This thesis focuses on the prediction of lightning activity by the Lightning Potential Index (LPI) in the COSMO numerical weather prediction (NWP) model that comprises 1- and 2-moment (1M and 2M, respectively) cloud microphysical schemes. The objective of this thesis is to investigate the correlation between the predicted lightning activity and the detected one (by the European network for lightning detection EUCLID). Events of the years 2018 and 2019 that recorded significant lightning activity over Czechia are considered for the analyses. For the first time over Czech region, the prognostic values of LPI calculated for each event are verified. In particular, the spatio- temporal distribution of the predicted vs. detected lightning activity is evaluated. Both spatial characterizations and diurnal course of detected lightning activity correspond well to the theoretical knowledge. Thus, spatial (horizontal) and temporal approaches are applied to verify the lightning activity prediction. The results of this thesis successfully verify the LPI prognostic values both in space by comparing the LPI values with the proximity of detected lightning flashes, and in time by contrasting the...
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