Three Regimes of Temperature Distribution Change over Dry and Wet Surfaces

Abstract:

Climate model simulations project different regimes of temperature distribution changes for dry and wet surfaces. The entire temperature distribution shifts over dry land surfaces, while moist land surfaces feature larger increases in extreme temperatures relative to the mean state. The latter indicates an elongated upper tail of the distribution, with extremes increasing approximately 20% more than the corresponding means. Oceanic surfaces show weaker warming relative to land surfaces, with no significant elongation of the upper tail. Dry land surfaces show little change in sensible (SH) or latent (LH) turbulent fluxes, with additional energy balanced mainly via radiation. By contrast, moist land surfaces show shifts of turbulent flux partitioning toward SH, while oceanic surfaces show shifts toward LH. Amplified warming of extreme temperatures over moist land surfaces is attributed to suppressed evapotranspiration and larger Bowen ratios. Changes in surface air temperature are not correlated with changes in net radiation.