Six Oceanic Convective Zones Impact the Climate in the Mid-Latitudes, Attributed to Rossby Waves Resonantly Forced

Geostrophic current velocity anomalies at the mid-latitudes of the three oceans are highlighted, and their role in the genesis of low-pressure systems in boreal/austral winter. These anomalies are attributed to quasi-stationary Rossby waves resonantly forced by the solar declination in harmonic modes. They develop along the western boundary currents as they leave the continents to re-enter the five subtropical gyres. In the North and South Atlantic, the thermocline behaves as a resonant cavity with rigid boundaries at the edges of the western boundary currents, i.e. the Gulf Stream and the Brazil Current, traversed by first-baroclinic mode, first-meridional mode Rossby waves. In the Indian Ocean, the retroflection of the Agulhas Current south of the African continent causes resonance in two different ways west and east of the Cape of Good Hope: resonance of second-baroclinic mode Rossby waves in the first case, and first-baroclinic mode Rossby waves in the second. The resonant forcing of second-baroclinic mode Rossby waves is also observed in the East Australian Current as it flows along Australia. In the North Pacific, resonant forcing of first-baroclinic mode Rossby waves is observed along the Kuroshio, off the east coast of Japan. Geostrophic current velocity anomalies are proving to be convective zones with a significant climatic impact. Within relevant period ranges, this is highlighted by the close coherence of 1 in the geopotential height anomalies at 500 hPa revealing a causal relationship between the geostrophic current velocity anomalies and the formation of low-pressure systems. The objective of this study is to identify the phenomena that precede the formation of winter low-pressure systems at mid-latitudes. The precursor signals observed in convective zones could be relevant candidates for anticipating these meteorological phenomena 10 to 15 days in advance using deep learning techniques.