Use of the reanalysis products for the hydrological rainfall-runoff modelling: Slovenian case studies : master thesis

Alexopoulos, Marcos (author), Bezak, Nejc (mentor), Šraj, Mojca (comentor)

Hidrološko modeliranje nemerjenih porečij je še vedno velik izziv, saj za taka porečja ni na voljo ali podatkov o pretokih ali podatkov o padavanih in temperaturi zraka. V zadnjih letih je bilo na tem področju narejenih veliko raziskav. Ena izmed metod, ki jih lahko uporabimo namesto točkovno merjenih podatkov, so podatki reanaliz, ki združujejo modelske izračune, točkovne meritve ter tudi satelitske in radarske podatke. Magistrska naloga analizira ustreznost dveh produktov reanaliz z vidika ustreznosti podatkov opadavinah in temperaturi zraka. Izbrana sta dva produkta, in sicer ERA5 in COSMO-REA6,ki sta v nalogi testirana na izbranih porečjih na območju Slovenije. Oba produkta imata na voljopodatke z urnim časovnim korakom in do sedaj z vidika hidrološkega modeliranja površinskegaodtoka še nista bila preverjena. Za modeliranje sta uporabljena enovita konceptualna modelaGR4H in CemaNeigeGR4H. Testirane so različne konfiguracije modelov (npr. s ponovnimumerjanjem ali brez le-tega). Ugotovljeno je bilo, da so podatki reanaliz primerni za uporabo samo za nekatera porečja, in sicer v primeru da hidrološki model ni ponovno umerjen na podatke reanaliz, ampak se privzame parametre, določene glede na točkovno izmerjene podatke. Ponovno umerjanje modela pa je izboljšalo rezultate modeliranja. Rezultati so pokazali, da se izbrana produkta reanaliz delno ujemata s točkovno izmerjenimi podatki, kar pomeni da ju lahko upoorabimo kot grobo oceno dejanskega stanja v primeru, da podatkov o padavinah in temperaturi zraka ni na razpolago.

• Language: English
• Keywords: Reanalize, Slovenija, ERA5, REA6, hidrološko modeliranje
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [M. J. Alexopoulos]
• Year: 2021
• PID: 20.500.12556/RUL-134156
• UDC: 556.512:004.41(043.3)
• COBISS.SI-ID: 92504323
• Publication date in RUL: 25.12.2021

ALEXOPOULOS, Marcos, 2021, Use of the reanalysis products for the hydrological rainfall-runoff modelling: Slovenian case studies : master thesis [online]. Master’s thesis. Ljubljana : M. J. Alexopoulos. [Accessed 5 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=134156

Secondary language

• Language: Slovenian
• Title: Uporaba produktov reanaliz za namen hidrološkega modeliranja: izbrani primeri v Sloveniji : magistrsko delo

Abstract

The need for hydrological modeling in ungauged basins has always been a major challenge. Efforts have been made in recent years to address it via the implementation of ex-situ technologies. An attractive option that is becoming increasingly popular are reanalysis products, which provide modeled data for atmospheric variables, based on observations assimilated from various sources, such as satellites and radar stations. The present study is focusing on the evaluation of two reanalysis precipitation and temperature datasets, namely ERA5 and COSMO-REA6, over a selection of drainage basins located in Slovenia. The two products are available at the hourly temporal scale, and at the time of writing, their quality has not been evaluated in rainfall-runoff applications over European borders. To measure their efficiency, the GR4H and GR4H Cema Neige lumped conceptual rainfall-runoff models were used. Different reanalysis configurations were tested by using the initial model parameters, calibrated using observed data. In addition, it was investigated whether the parameters ingrained within the model are able to make up for low rainfall and temperature data quality, by recalibrating them on every reanalysis configuration. Initial model runs proved to be adequate only for a few catchments out of the total selection. However, the recalibration process was effective in increasing hydrological performance, increasing the total number of watersheds that were modeled accurately. The study concluded that the two products are partially in agreement with observations, suggesting their use as a proxy when observed data is scarce.

• Keywords: Reanalysis, Slovenia, ERA5, REA6, Hydrological application