The dry side of stones and the rainbow
by François Dulac, CEA/LSCE, Saclay, France
At Kerguelen Island at the limit between the Roaring Forties and Furious Fifties in the remote southern Indian Ocean, wind storms are frequent even in summer (more than 30 m/s is observed every month). This yields quasi horizontal rainfall so that the soil and the side of rocks and stones on the ground downwind remain perfectly dry during rain showers. In addition very clean air, low sun and water clouds at low-level over the cold ocean make rainbows relatively frequent.
During our summer field campaign in early 2005, we experienced the nightmare of walking against such a rain event. Low pressure sytems are passing so fast that we also experienced facing high wind both on our way in the morning and on our way back in the afternoon !
François Dulac (distributed via imaggeo.egu.eu)