Satellite measurements of cloud properties and the radiation budget are essential for understanding meso- and large-scale processes that determine the variability in climate over the eastern Pacific. Remote sensing from satellites can provide a wealth of information about clouds and radiation, but it is important to validate the remotely sensed parameters are validated and to understand their relationship to other parameters that are not directly observed by the satellites. The variety of measurements from the R/V Ron Brown that were taken during the EPIC cruises, especially EPIC 2001, are suitable for validating and improving the interpretation of the satellite data. In situ measurements taken by a Twin Otter over the Pacific off the California coast during the Drizzle and Entrainment Study (DECS) are valuable for further understanding the true nature of the cloud properties, especially in the drizzle environment that commonly occurs within marine stratus and stratocumulus clouds.
In this study, satellite-derived cloud properties including coverage, height, optical depth, and effective droplet radius re are compared with both the ship and in situ measurements taken during the EPIC cruises and DECS to validate the satellite retrievals and to understand how the retrieved parameters relate to other cloud properties of interest including cloud base height and drizzle. The remotely sensed values are derived from 4-km hourly Geostationary Operational Environmental Satellite (GOES) imager data, 4-km Advanced Very High Resolution Radiometer radiances, 2- km Visible Infrared Scanner data from the Tropical Rainfall Measuring Mission satellite, and 1-km Moderate Resolution Imaging Spectroradiometer data from the Terra satellite. The in situ data include cloud droplet size distributions and cloud top and base heights. The ship data include radar and radiometer based retrievals of cloud-top and base heights, cloud amount, liquid water path, and effective droplet radii. The results of this study will be valuable for better utilization of the PACS satellite-derived cloud properties and subsequently for improving our understanding of the role of clouds and drizzle in the circulation over the eastern Pacific.