RT info:eu-repo/semantics/doctoralThesis
T1 Transiciones tropicales en el Atlántico Norte: génesis y simulaciones numéricas
A1 Calvo Sancho, Carlos
A2 Universidad de Valladolid. Escuela de Doctorado
K1 Meteorología
K1 Tropical Transitions
K1 Transiciones Tropicales
K1 North Atlantic
K1 Atlántico Norte
K1 Iberian Peninsula
K1 Península Ibérica
K1 Harmonie-arome
K1 22 Física
AB Tropical Transition (TT) is the process by which a baroclinic cold-core cyclone loses its asymmetry and gradually acquires typical characteristics of warm-core symmetrical tropical cyclones, ending up as a purely tropical cyclone. Due to the multiple societal impacts associated with TTs, these cyclone transition processes have received increased attention from the scientific community and forecasters in recent decades. This dissertation aims to analyze TTs in the North Atlantic under the present climate by studying their genesis and evolution using atmospheric reanalysis databases and numerical simulations, to improve the general knowledge of cyclones that have undergone these transition processes.The different studies that compose this dissertation have focused on the elaboration of a climatology of TTs. The kinetic energy associated with these atmospheric systems has been studied by analyzing the energy spectrum associated with both reanalysis and simulations of various TTs. In addition, the effective resolution of several limited-area models when simulating these systems has been analyzed by comparing it with that obtained from the reanalysis database. The numerical models used for the simulation of TTs were WRF-ARW and HARMONIE AROME. Finally, the verification of TTs simulations performed by these models has been carried out using several traditional and object-based techniques. In this dissertation, the synoptic environments of cyclones that have undergone a TT process in the North Atlantic have been analyzed using the ERA5 reanalysis database, differentiating between the central and the eastern North Atlantic. The results obtained indicate that TTs in the North Atlantic are characterized by an anticyclonic blocking pattern northward of a surface low with increasing geopotential thickness, showing the development of the warm core. Cyclones in the eastern North Atlantic transition into an environment more hostile to tropical cyclogenesis than the central North Atlantic.The kinetic energy spectrum curve in the ERA5 atmospheric reanalysis has been analyzed in different latitudinal bands in the Northern Hemisphere and a limited-area domain in the North Atlantic. The results show that ERA5 can correctly reproduce the kinetic energy spectrum at the synoptic scale, without correctly in mesoscale regions. Because of this handicap, several tropical cyclones that have undergone a TT process have been numerically simulated to analyze and evaluate the importance of each of the terms by an energy budget. The obtained results indicate that the HARMONIE-AROME model shows a higher numerical dissipation filtering, while the WRF-ARW model tends to over-energize the spectrum. The kinetic energy is mainly dominated by the terms associated with strong updrafts and moist convective processes in the energy cascade and other energy transfer processes.The HARMONIE-AROME and WRF-ARW models have been verified in the area of TTs using traditional and object-oriented methods. Both models show very similar results in the evaluation of the trajectory of the simulated TTs and a general overestimation of the maximum wind speed at 10 m in both models. The brightness temperature and the three-hour cumulative precipitation fields were evaluated using object-oriented verification methods (SAL and FSS). The HARMONIE-AROME (WRF-ARW) model resolves precipitation better in the pre (post)-TT phase. However, the WRF-ARW (HARMONIE-AROME) model resolves the brightness temperature better compared to SEVIRI-MSG in the pre (post)-TT phase. Therefore, based on the results obtained, it is difficult to determine the optimum numerical model resolving the cyclones that have undergone a TT process.
YR 2024
FD 2024
LK https://uvadoc.uva.es/handle/10324/71596
UL https://uvadoc.uva.es/handle/10324/71596
LA spa
NO Escuela de Doctorado
DS UVaDOC
RD 22-dic-2024