North-western Mediterranean sea-breeze circulation in a regional climate system model

Abstract

regional climate model (AORCM) coupling WRF and NEMO-MED12 in the frame of HyMeX/MED-CORDEX are compared. One result of this study is that these simulations reproduce remarkably well the intensity, direction and inland penetration of the sea breeze and even the existence of the shallow sea breeze despite the overestimate of temperature over land in both simulations. The coupled simulation provides a more realistic representation of the evolution of the SST field at fine scale than the atmosphereonly one. Temperature and moisture anomalies are created in direct response to the SST anomaly and are advected by the sea breeze over land. However, the SST anomalies are not of sufficient magnitude to affect the large-scale seabreeze circulation. The temperature anomalies are quickly damped by strong surface heating over land, whereas the water vapor mixing ratio anomalies are transported further inland. The inland limit of significance is imposed by the vertical dilution in a deeper continental boundary-layer.

Editorial for the Med-CORDEX special issue

“…The authors suggest that main drawbacks of the RCMs is not the representation of the mean moisture or of the CAPE (Convective Available Potential Energy) but rather in the vertical distribution of moisture and in the triggering of deep convection. Drobinski et al (2017) show that a standard RCM at 20 km resolution is able to reproduce the intensity, direction and inland penetration of the sea breeze in the north-western Mediterranean Sea. The authors suggest that high-frequency air-sea coupled effects and the related SST anomalies are only weakly influencing this phenomena.…”

“…Other studies of the special issue focus on the evaluation of specific climate phenomena of the region such as the cyclones (Flaounas et al 2016; Sanchez-Gomez and Somot 2016), the medicanes (Gaertner et al 2016), the cloud cover (Chakroun et al 2016), the ocean deep water formation (Somot et al 2016;Dunić et al 2016), the regional winds (Obermann et al 2016) and the sea breeze (Drobinski et al 2017).…”

Links Between Sea Surface Temperature Structures, Clouds and Rainfall: Study Case of the Mediterranean Sea

“…In order to better assess SST effects on wind divergence, a coastal mask is applied on each field. It covers a strip of about 50 km off the coast over which atmospheric dynamics is also driven by several different processes such as land‐sea breeze and orographic effects (e.g., Drobinski et al., 2018; Buzzi et al., 2020). A discussion about the width of the coastal mask is provided in the supportive information document.…”

Climate‐Driven Characteristics of Sea‐Land Breezes Over the Globe

“…This is a classical method and has many limitations with respect to the accurate representation of real evolution processes (Haurwitz, 1947). After the 1950s, numerical calculations were used to solve the nonlinear parts of the motion equations (Pielke, 1974), as a result of which a variety of regional‐scale models, such as the Regional Climate Model (RCM) and Atmosphere‐Ocean Regional Climate Model (AORCM) were used to reveal the SLB's evolution (Drobinski et al., 2018).…”

“…Atmosphere-Ocean Regional Climate Model (AORCM) were used to reveal the SLB's evolution (Drobinski et al, 2018).…”