The change of cloud liquid water path on temperature over polar areas

The variations of cloud liquid water path LWP with cloud temperature are examined using a combination of surface and satellite data taken during the 1998 Surface Heat Budget of the Arctic Ocean and the FIRE Arctic Clouds Experiments. The results show that LWP increases with temperature primarily because of an increase in cloud thickness that is enabled by the rise in surface moisture during the melt season. Cloud base heights and lifting condensation levels decrease as a result of the greater surface relative humidity and temperature. The average change rate of LWP with cloud temperature is 3.3%/K, a value slightly smaller than earlier observations taken over cold mid-latitude land areas. This cloud LWP feedback with temperature differs significantly from that estimated over other marine environments and should be taken into account in climate models with explicit cloud feedbacks.