Comparison of Urban Mixing Layer Height from Ceilometer, Radiosonde and WRF Model

The diurnal variation of summertime mixing layer height (MLH) over Sofia, Bulgaria retrieved from ceilometer profiles is compared to boundary layer height simulated by Advanced Research WRF (ARW) mesoscale numerical weather prediction model. Validation of both simulated by WRF and retrieved from ceilometer MLHs during five days in August 2015 is accomplished by using of radiosonde thermodynamic profiles as a reference. Although based on different tracer MLHs derived from ceilometer and radiosonde showed significant matching. Through sensitivity analysis of nine planetary boundary layer parametrization schemes in WRF is found that five of them: Yonsei University (YSU), quasi-normal scale elimination (QNSE), Bougeault-Lacarrre (BouLac), Mellor-Yamada Nakanishi and Niino Level 2.5 and 3 (MYNN2.5, MYNN3) outperform the rest. It is also shown that augmented surface heat capacity and roughness in the city significantly modify urban MLH growth rate, especially in early evening.