Unit:
Department of PhysicsLibrary of the School of Science
Dissertation committee:
Φλόκα Έλενα, Καθηγήτρια, Τομέας Φυσικής Περιβάλλοντος-Μετεωρολογίας, Τμήμα Φυσικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών Ε.Κ.Π.Α.
Κάλλος Γεώργιος, Ομότιμος Καθηγητής, Τομέας Φυσικής Περιβάλλοντος-Μετεωρολογίας, Τμήμα Φυσικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών Ε.Κ.Π.Α.
Λουκά Πετρούλα, Επίκουρος Καθηγήτρια, Τομέας Μαθηματικών και Φυσικών Επιστημών, Τμήμα Αεροπορικών Επιστημών, Σχολή Ικάρων
Τόμπρου Μαρία, Καθηγήτρια, Τομέας Φυσικής Περιβάλλοντος-Μετεωρολογίας, Τμήμα Φυσικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών Ε.Κ.Π.Α.
Αργυρίου Αθανάσιος, Καθηγητής, Τομέας Εφαρμοσμένης Φυσικής, Τμήμα Φυσικής, Πανεπιστήμιο Πατρών
Κατσαφάδος Πέτρος, Aναπληρωτής Καθηγητής, Τμήμα Γεωγραφίας, Χαροκόπειο Πανεπιστήμιο
Πυθαρούλης Ιωάννης, Aναπληρωτής Καθηγητής, Τομέας Μετεωρολογίας και Κλιματολογίας, Τμήμα Γεωλογίας, Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης
Original Title:
ΑΝΑΠΤΥΞΗ ΜΕΘΟΔΟΛΟΓΙΑΣ ΓΙΑ ΤΗΝ ΑΞΙΟΛΟΓΗΣΗ ΠΡΟΓΝΩΣΤΙΚΩΝ ΠΕΔΙΩΝ ΒΡΟΧΟΠΤΩΣΗΣ ΥΨΗΛΗΣ ΧΩΡΙΚΗΣ ΑΝΑΛΥΣΗΣ ΣΕ ΠΟΛΥΠΛΟΚΟ ΑΝΑΓΛΥΦΟ ΜΕ ΤΗ ΧΡΗΣΗ ΡΕΑΛΙΣΤΙΚΩΝ ΠΛΕΓΜΑΤΙΚΩΝ ΠΑΡΑΤΗΡΗΣΕΩΝ
Translated title:
DEVELOPMENT OF METHODOLOGY FOR THE EVALUATION OF HIGH RESOLUTION PRECIPITATION FORECAST FIELDS OVER COMPLEX TERRAIN WITH THE USE OF REALISTIC GRIDDED OBSERVATIONS
Summary:
Verification of precipitation forecasts is a very challenging task. High-resolution models are able to produce more detailed precipitation structures, but their primary benefit lies in delivering more realistic fields rather than the information provided for a specific grid point. Spatial verification methods generally reward closeness or resemblance by relaxing the requirement for exact matches between forecasts and observations that is the cause of double penalty errors in traditional approaches. Spatial precipitation fields derived from numerical weather prediction (NWP) model output are produced in the form of grids. In order to assess their accuracy with spatial verification methods, it is necessary to transpose any available observations (ground stations, radar products, satellite estimates) to the same grid. The challenge is to overcome the lack of density of observations in both time and space to accurately represent the highly variable nature of precipitation.
In this thesis, the MISH (Meteorological Interpolation based on Surface Homogenized Data Basis) method is used to estimate the distribution of precipitation on both hourly and daily timescales. The idea behind the MISH interpolation scheme stems from the principles that gridded data can be created at higher quality when correlated with certain climate statistical parameters (geophysical characteristics), which can be modelled using long climate data series. The modelling of the statistical parameters for a given location is based on the long-term homogenized monthly data of neighbouring stations. In order to better exploit the information from stations neighbouring each grid point, remote sensing precipitation estimates are added as background information, which is evaluated in combination with the interpolated value.
Subsequently, the precipitation forecasts are assessed using various spatial methods in an effort to identify the ability of each verification approach to provide distinctly useful information on model performance. The methods chosen represent different approaches in model evaluation strategy, such as that of neighborhood or fuzzy, scale separation and object-oriented techniques. Model output of the limited area COSMO model at two different resolutions is compared to the gridded precipitation fields created by MISH for four different test cases over Greece in an effort to obtain answers to questions related to their performance at different scales, to their location errors, intensity errors and distributions and to the precipitation forecast structure errors.
Finally, the development of an integrated verification system for precipitation forecasts is proposed that meets the requirements of an operational system. The evaluation framework can flexibly incorporate all available observation sources and meet the needs of a wide range of users based on the various statistical approaches it applies. The system is adapted to the specificities of the Greek territory, consequently it can provide sufficient feedback on the performance of very high resolution NWP models in areas with extreme topography where in situ observations are too limited to accurately represent the phenomena.
Main subject category:
Science
Keywords:
Numerical Weather Prediction, Verification, Precipitation, Gridded Observations
Number of references:
130
File:
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Thesis-FloraGofa-07092020-COLOR.pdf
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File access is restricted only to the intranet of UoA.
