Intercomparison of retrieved liquid water cloud properties at Pt. Reyes, California during MASRAD

The Department of Energy's Atmospheric Radiation Measurement (ARM) program deployed its mobile facility to Pt. Reyes, California, as part of the Marine Stratus Radiation Aerosol and Drizzle (MASRAD) IOP from 14 March through 14 September 2005. The primary purpose of this experiment was to study the microphysical and radiative characteristics of marine stratus, one of the most prevalent cloud types on the planet. These liquid water clouds are often low to the surface and have relatively low liquid water path (LWP); LWPs < 100 g/m2 are very common. In order to characterize the influence of aerosols on this cloud type, accurate retrievals of LWP and effective radius are required. Several ground-based remote sensors were available during MASRAD to characterize the cloud properties, including a two-channel microwave radiometer, a twelve-channel profiling microwave radiometer, a two-channel narrow field-of-view radiometer, an Atmospheric Emitted Radiance Interferometer, a multi-filter rotating shadowband radiometer, and a 94 GHz cloud radar. Cloud properties retrieved from these instruments will be intercompared, and compared with both aircraft-based in-situ observations and MODIS retrievals. Closure exercises, both in terms of shortwave diffuse flux and radar reflectivity, will also be shown to help characterize the accuracy of the different retrieval methods. This study will quantify the uncertainties in each retrieval method and provide the dataset needed to investigate the influence of aerosols on these clouds.