The ‘Storm Curtain’ Effect: Poleward Shift of Clouds, Their Radiative Effects, and the Role of Midlatitude Storms

Abstract

Midlatitude storm track density shifts are correlated with satellite-derived cloud properties and radiation effects. We find that high-cloud amount constitutes the primary tracer of storm track shifts, and that high clouds have been shifting poleward in the 1984–2009 time period by 0.30–0.46 degrees per decade in all four major oceanic storm track regions. Driven by the poleward shift of high clouds, the total cloud field and the cloud radiative effect have also been shifting poleward at a rate of 0.12–0.23 degrees per decade, similar to the rate of the poleward shift of the storms in three out of the four major oceanic storm tracks. This poleward total cloud amount shift produces a change in the radiative effect of storm clouds as they move to a region of lower solar insolation.