Climate Change and storminess in the Gulf of Lion: a spatio-temporal scale interaction approach

Coastal flooding in the Gulf of Lions is associated with storm-surges linked with southeasterly winds that push up the water toward the coasts. At a synoptic scale, these meteorological conditions are associated with a deep barometric depression near the Bay of Biscay. This is favored by the negative phase of the North-Atlantic Oscillation that leads to a southward shift of the main stormtrack over the northern Atlantic. In the second half of the 20th century, the frequency of southeasterlies shows a significant increase in the whole Gulf of Lions, paradoxically with the positive deviation of the North-Atlantic Oscillation. Changes in the mean atmospheric conditions at this broad spatial-scale have increased the probability of barometric depression near the Bay of Biscay and of southeasterlies in the Gulf of Lions during negative phase of the North-Atlantic Oscillation.