Quantification of the accuracy of liquid water path fields derived from NOAA 16 advanced very high resolution radiometer over three ground stations using microwave radiometers

Abstract

Measurements of solar reflectivities at 0.63 and 1.6 μm from the advanced very high resolution radiometer (AVHRR) instrument on board NOAA 16 were used to estimate the cloud liquid water path (LWP). The cloud analysis involves cloud particle phase classification and estimation of the spatial distribution of the optical thickness and droplet effective radius. The retrieved satellite LWP was validated with time series of LWP measurements retrieved from ground-based microwave radiometers made during the intensive measurement campaigns of the Cloud Liquid Water Network project (CLIWA-NET). The cases were screened for occurrence of ice clouds and precipitation. In total, 91 colocated observations of cumuliform and stratiform cloud fields from three measurement sites and over 4 months were used for error quantification. For the total set the correlation coefficient is 0.88, with a slope of 1.06 and an intercept of 3.0 g m-2. The root-mean-square error is about 28 g m-2. The analysis shows that AVHRR, together with a ground-based microwave radiometer, can be used to retrieve spatial distributions of LWP with acceptable accuracy for atmospheric model evaluation. Copyright 2005 by the American Geophysical Union.