بررسی شکست‌های واچرخندی و چرخندی امواج راسبی در شرق مدیترانه(E15-45) از دیدگاه انرژی

The wave breaking on the upper levels troposphere effect on the wave activity flux and the influence of trough on the lower levels troposphere. In this research with using the ERA-Interim reanalysis data that covered span the years 1979-2018 for the winter months (15December to 15April). First the Hovmoller diagram of potential vorticity and temperature at 200hPa level in the cyclonic (anticyclonic) wave breaking was shown was assessed. the result showed that during the five days before to five days after the wave breaking the potential vorticity in the downstream trough increase to 6.5PVU alternatly. It is accompanied by alternative anomalies of temperature in 200hPa level. The influence of the stratospheric atmosphere to troposphere is causes to increase upper levels temperature and vorticity at trough area. And the influence of the tropospheric atmosphere to stratosphere is causes to decrease upper levels temperature and vorticity at ridge area. Previous study showed that Rossby wave breaking mechanism is similar in the different area at east of Atlantic ocean until west Asia. In these regions the meridional wave activity flux due to anticyclonic wave breaking is more than in the cyclonic wave breaking. But equatorward (poleward) wave activity flux in the anticyclonic (cyclonic) wave breaking on the east of Atlantic ocean and Europe is similar to (twice as many) in the east of Mediterranean and west Asia.

During anticyclonic (cyclonic) wave breaking, jet in the upstream of trough is weaken and Also equatorward (poleward) wave activity flux in the downstream of trough is weaken and divergence region of wave activity flux split in two region over Europe and Meditranean area. It is seemed that during the wave breaking firestly upper part of wave passes from midlatitude then lower part of wave passes from subtropical latitude. In this research for appearing the mater The ensemble mean of vertical average of the eddy kinetic energy and the forcing terms of the eddy kinetic energy tendency as well as The baroclinic convergence (BCC), baroclinic generation (BCG) representing the generation of available potential energy, barotropic convergence (BTC), ageostrophic geopotential height flux convergence is calculated and studied for the breaking waves events on the east of Mediterranean sea.

The results showed that during the five days before the wave breaking event, the eddy kinetic energy tendency is positive on the downstream trough and the eddy kinetic energy has intensified in the different latitude over the Europe and Mediterranean sea until wave breaking days. In the Anticyclonic (cyclonic) wave breaking events day the energy tendency was reduced in the downstream of trough and the energy center separate into two center at different latitude across the line north‌westerly-south-easterly (north‌easterly-southwesterly). Energy center is stronger on the lower latitude over the east of Mediterranean sea in the anticyclonic break and in the upper latitude over the Europe in the cyclonic break. during the five days before the wave breaking event, The ageostrophic geopotential height flux eddies Formation in different latitude causes the energy advection from upstream to downstream trough and intensify the energy centers. Also vertical motion and temperature gradient increase causes the formation of eddy kinetic energy tendency terms as well as BCC, BCG terms on the downstream of troughs. The jets settlement in downstream of troughs causes formation the BTC term. The ageostrophic geopotential height convergence has the most effect on the energy tendency magnitude that during the wave breaking day decrease similar to the another terms. The magnitude of the ageostrophic geopotential height convergence is twice as large as the BCC element and fourfold as large as the BCG and BTC elements.

almost In the wave breaking days the eddy energy center diverge into two region with different latitude and the wave convert to two separete waves at different latitude across the north‌easterly-south‌westerly (north‌westerly-south‌easterly) axes. In the five days after wave breaking, firstly the waves in the upper latitude pass to the east and their energy centers are weaken then the waves in the lower latitude pass. however the forcing terms and the energy centers are weaken after wave break but almost during the fifth days after wave break the ageostrophic geopotential height convergence forcing term intensify again that caused to increase the eddy energy and the other wave pass across two latitude.