A MODIS-derived Value-Added Climatology of Maritime Cloud Liquid Water Path That Conserves Solar Reflectance

Abstract

dataset is generated from a method to retrieve distributions of cloud liquid water path over partially cloudy scenes. The method was introduced in Foster et al. (2011), which described the theory and provided test cases. Here it has been applied to MODIS Collection 5 and Collection 6 cloud products, resulting in a value-added dataset containing adjusted distributions of cloud liquid water path over a decade in length for marine liquid cloud for both Aqua and Terra. This method adjusts horizontal distributions of cloud optical properties to be more consistent with observed visible reflectance and is especially useful in areas where cloud optical retrievals fail or are considered low quality. Potential uses of this data set include climate model and radiative transfer model validation and facilitating satellite record inter-comparison studies. Results show that the fit methodology is able to reduce bias between observed visible reflectance and that derived from optical retrievals by up to an average improvement of 3%. The level of improvement is dependent on several factors including seasonality, viewing geometry, cloud fraction and cloud heterogeneity. Applications of this data set are explored through a satellite intercomparison with PATMOS-x and GCOM-W1 AMSR-2 and use of a Monte Carlo radiative transfer model. From the 3D Monte Carlo model simulations, albedo biases are found when the method is applied with seasonal averages ranging from 0.02-0.06.