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New parameterizations in the RegCM model
Pitaš, Ondřej ; Belda, Michal (advisor) ; Karlický, Jan (referee)
This thesis compares new physical parameterizations in the regional climate model system RegCM with the standard settings used at the Department of Atmospheric Phy- sics and observed climatic conditions. The first part is dedicated to the description of individual parameterizations and to the essential introduction to the RegCM model. In addition, model preprocessing and running simulations are discussed. The simulations were conducted over Europe domain for the ten-year period (1990-1999) with five dif- ferent model settings. Holtslag PBL(Holtslag, 1990) type boundary layer scheme, Grell cumulus convention scheme over land and ocean and Explicit moisture scheme (SUBEX; Pal et al 2000) were used in the reference simulation. In the conducted simulations, the following physical parametrizations were used separately: UW PBL (Bretherton and McCaa, 2004) boundary layer scheme, Explicit moisture Nogherotto/Tompkins mois- ture scheme, Tiedtke (1996) and Kain-Fritsch (1990) & Kain (2004) cumulus convention schemes over land and ocean. None of the new physical parameterizations showed impro- vements over standard setting in all analyzed variables at the same time. Precipitation is best described by reference simulation as well as by simulations with UW PBL and Kain- Fritsch & Kain parametrization type. Kain-Fritsch...
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Validation of snow cover forecast by numerical weather prediction model ALADIN
Ševčík, Jáchym ; Žák, Michal (advisor) ; Karlický, Jan (referee)
This thesis deals with forecast of snow cover made by the numerical weather predic- tion model ALADIN and with snow cover measurements. First, it describes the model parametrization of snow-related variables. This is followed by a description of the mete- orological stations network and of the snow measurements methodology. The main focus of the thesis lies on the validation of snow depth and snow water equivalent forecasts. This is done by comparison of measurements from the winter season 2021/2022 against corresponding ALADIN forecasts with forecast ranges of 6 and 30 hours. The comparison is first made with regard to the overall tendency and the magnitude of the model error. Secondly, it deals with model frequency of snow cover misses or false alarms. Finally, the thesis touches upon the validation of snow density forecast. 1
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Validation of WRF-Chem and CAMx atmospheric model outputs with focusing on tropospheric ozone
Peiker, Jan ; Karlický, Jan (advisor) ; Bednář, Jan (referee)
The atmospheric model accuracy is substantially influenced by quality of boundary conditions used by physical and chemical part of the model. The thesis evaluates the development of the model output accuracy in case of using global model outputs as boundary conditions, instead of interpolated observation data (so-called reanalyses). For this purpose, two atmospheric models WRF-Chem and CAMx with three different combinations of boundary conditions were used, thus 6 simulations in total. The simulations were performed in the domain cove- ring central Europe and were compared with data from 165 stations. The results have shown narrower distribution functions of the simulated data in general and different seasonal overestimation in both models. The substitution of original boundary conditions for those adopted from global models has shown that the replacement of meteorological boundary conditions has decreased the correlati- ons between simulations and measurements, whereas the replacement of chemical boundary conditions has increased the overestimation of both models. 1
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Model WRF and its application for regional climate modelling in high resolution
Karlický, Jan ; Halenka, Tomáš (advisor) ; Belda, Michal (referee)
This work is dealing with regional climate models. Firstly, their principle and use of them is described, including advantages and disadvantages of this approach. Further, the application of WRF numerical weather prediction model in climate mode is described and differences in use of CLWRF modification and its advantages for getting results are discussed. Possibilities of this implementation and testing runs for finding appropriate settings are presented. Finally, the results of one ten-year and four five-year simulations of model with different settings are compared with observed values. Some chapters are dedicated to possibilities of processing and graphics outputs of model results and discussion.
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Study of screen level temperature dependency on interactions and feedbacks of physics parameterizations in numerical weather prediction and climate models.
Švábik, Filip ; Huszár, Peter (advisor) ; Karlický, Jan (referee)
Screen level temperature is measured at 2 meters above the ground. It is one of the most used atmospheric characteristics in various applications in meteorology and other fields related to weather prediction. Essential is not only the knowledge of its current state, but also its prediction. It is forecasted by numerical weather prediction (NWP) models from the atmospheric current state. Its long-term characteristics can be obtained from the integration of climate models. This text discusses fundamental parametriza- tions, mostly related to temperature forecast, used in the NWP model ALADIN and the regional climate model RegCM. Physical processes which influence temperature are studied using ALADIN in several cases which include the presence of low cloudiness, gravity waves and inappropriate thermic coefficient. A detailed description of the most relevant parametrization schemes is given and the results are studied in a form of indi- vidual feedback loops. Most dominant processes are also found. However, the level of 2 meters above the ground is not the model level, so temperature at 2 meters is obtained by interpolation from the surface temperature and the lowest model level temperature. Using RegCM, two differently complex interpolation schemes are compared to each other. 1
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New parameterizations in the RegCM model
Pitaš, Ondřej ; Belda, Michal (advisor) ; Karlický, Jan (referee)
This thesis compares new physical parameterizations in the regional climate model system RegCM with the standard settings used at the Department of Atmospheric Phy- sics and observed climatic conditions. The first part is dedicated to the description of individual parameterizations and to the essential introduction to the RegCM model. In addition, model preprocessing and running simulations are discussed. The simulations were conducted over Europe domain for the ten-year period (1990-1999) with five dif- ferent model settings. Holtslag PBL(Holtslag, 1990) type boundary layer scheme, Grell cumulus convention scheme over land and ocean and Explicit moisture scheme (SUBEX; Pal et al 2000) were used in the reference simulation. In the conducted simulations, the following physical parametrizations were used separately: UW PBL (Bretherton and McCaa, 2004) boundary layer scheme, Explicit moisture Nogherotto/Tompkins mois- ture scheme, Tiedtke (1996) and Kain-Fritsch (1990) & Kain (2004) cumulus convention schemes over land and ocean. None of the new physical parameterizations showed impro- vements over standard setting in all analyzed variables at the same time. Precipitation is best described by reference simulation as well as by simulations with UW PBL and Kain- Fritsch & Kain parametrization type. Kain-Fritsch...
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Model WRF and its application for regional climate modelling in high resolution
Karlický, Jan ; Halenka, Tomáš (advisor) ; Belda, Michal (referee)
This work is dealing with regional climate models. Firstly, their principle and use of them is described, including advantages and disadvantages of this approach. Further, the application of WRF numerical weather prediction model in climate mode is described and differences in use of CLWRF modification and its advantages for getting results are discussed. Possibilities of this implementation and testing runs for finding appropriate settings are presented. Finally, the results of one ten-year and four five-year simulations of model with different settings are compared with observed values. Some chapters are dedicated to possibilities of processing and graphics outputs of model results and discussion.
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