Passive microwave retrievals of precipitation over the Southern Ocean

Many algorithms have been developed to retrieve precipitation and cloud liquid water from passive microwave measurement at mid-latitudes and in the tropics, but these algorithms do not necessarily work well over the ice-free oceans that surround the Antarctic continent where most precipitation falls in the form of snow.It is known that the clouds that produce most of the precipitation over the southern latitudes are thin stratiform clouds and the precipitation they give is of slight intensity (less than 0.5mm h -1 rain equivalent). In this paper the polarization corrected temperature (PCT) method for detecting precipitation is applied and compared with a new physical method that simultaneously retrieves both cloud liquid water and precipitation amount. Both methods are compared with the few in situ measurements available. The new iterative physical method is found to give better results and does not need any empirically derived parameters.

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