The aim of the present thesis was the sensitivity study of two urban parameterizations integrated into the non-hydrostatic numerical WRF model. One of them represents the effects of urban morphology (i.e., buildings and roads) and human activities inside cities (BEP-BEM), while the other offers a more simplistic approach of the urban climate (BULK). The model setup consisted of a two-domain configuration. The parent domain covered Europe at a horizontal resolution of 12 km, with a one-way nested inner domain centered over the region of France and Benelux at a horizontal resolution of 3 km. The study focused on the greater Paris area, while three periods were selected for evaluation: 1) a convective event occurred in May 2020, 2) the summer of 2020 (June-August) and 3) a heatwave event taken place in August 2020. We conducted four tests: one with the BULK approach and three using BEP-BEM in varying levels of complexity. Furthermore, in two of the BEP-BEM simulations high-resolution urban morphological options tailored specifically for the Paris region were utilized, derived from earth observation (EO) data, in an effort to better represent the urban form (i.e., building heights, road widths, etc.) of Paris. In one of those two simulations, further changes to the air-conditioning (A/C) operating hours were introduced. Additionally, in order to evaluate simulations in the representation of the urban heat island effect, two masks were created (an urban and rural one) based on threshold values of static variables inside WRF. Observational data from weather stations were obtained to evaluate the performance of each run. All four simulations appeared to have a similar error trend: overestimation of 2-m air temperature during nighttime hours for the summer and the heatwave event. The simulation with the advanced tailored urban characteristics over Paris had the best overall performance in summer 2020, while the modification of A/C working hours further improved performance at nighttime hours, during the heatwave event.
Ηρακλής Ν. Κυριακίδης (Wed,) studied this question.