About WRF scheme modeling for the period 2016 Sep 17-18

Four ABL schemes have been tested: the local ABL schemes (with TKE closure) Mellor-Yamada-Janjic (MYJ) based on our previous experience in simulating closed sea breeze cells and the Bougeault-Lacarrère (BouLac) , the nonlocal Yonsei University scheme (YSU) and the hybrid local–nonlocal Asymmetric Convective Model (ACM2) with non-local upward mixing and local downward mixing. MYJ ABL scheme can be coupled with the Eta-similarity surface layer scheme , while YSU and ACM2 schemes with MM5-similarity surface layer scheme. The BouLac ABL scheme can be coupled either with MM5 or Eta-similarity surface layer schemes. Here we choose MM5-similarity scheme for simulation with BouLac ABL scheme.

Synoptic overview

The synoptic situation for 17-18 September 2016 is favorable for extreme winds – the high pressure over studied area is replaced by warm frontpassing from west to east. The surface winds at the coastline are within 4-6 m/s with some windgusts around 8-10 m/s. At the end of the period a low pressure system is established over the region. The surface winds redirect from south, south-east in northern part of Bulgarian coastline and unstable windirection in Ahtopol itself.

Synoptic situation over Europe, 17 September 2016, 00UTC

Synoptic situation over Europe, 18 September 2016, 00UTC

Sodar measurements

WRF output

MYJ scheme results


YSU scheme results


ACM2 scheme results


BouLac scheme results

Differences (Sodar data – WRF data)

MYJ scheme


YSU scheme


ACM2 scheme


BouLac scheme

Correlations

MYJ scheme


YSU scheme


ACM2 scheme


BouLac scheme