Coupled Ocean-Wave-Atmosphere Modeling of a Cold Wake Producing Mediterranean Cyclones

Strong Mediterranean cyclones displaying characteristics of tropical cyclones, known as medicanes, can produce cold wakes as evidenced by remotely sensed sea surface temperature (SST) data. This was the case of Ianos which hit Greece during the third week of September 2020. Coupled model simulations have shown the negative feedback of the intense cold wake (ΔSST>4°C) on Ianos’ intensity.

Here we detail processes at play at and on either side of the interface in a series of high resolution (1.8 km) coupled ocean-wave-atmosphere simulations. The coupled framework consists of the atmospheric model Meso-NH, the 3rd generation wave model WAVEWATCH III®, and the oceanic model CROCO. We contrast the impact of ocean-atmosphere coupling without waves to full 3 way coupling with and without sea spray physics. Waves and sea spray accentuate the asymmetry of the storm. Sensitivity to sea spray generation functions for 10-m winds up to ~35 m/s is assessed. Two separate cold wakes are formed with large scale freshening in the second one. Ocean temperature budget analysis allows distinguishing key processes and interplay between storm induced and local dynamics. Available in situ and satellite-borne observations are used to validate results. These are further compared with coupled simulations using WRF (atmosphere), SWAN/WW3 (waves) and ROMS (ocean) highlighting the sensitivity to the model framework.