Multi-platform Inter-comparison of cloud fields during HI-SCALE campaign over the ARM-SGP site

Clouds play important role in weather, the radiation budget, and earth's hydrological cycle. Estimates of the spatial and temporal distribution of clouds can vary depending on the instrument platform, instrument sensitivity, as well as how the data is processed. Since there are large spatial and temporal variations of clouds in atmospheric columns, multiplatform observations are needed for better coverage and reducing the uncertainty of quantifying the cloud field distributions. The Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecosystems (HI-SCALE) campaign was designed to provide a detailed set of multi-platform measurements in 2016 to obtain a more complete understanding of shallow clouds and their coupling to land surface properties over the Atmospheric Radiation Measurement (ARM) Southern Great Plain (SGP) surface site. Initial analysis of cloud properties from ground based Raman Lidar and geostationary satellite observations show a strong diurnal variation over SGP, as expected. The average shallow cloud fraction (cloud top altitude < 3 km) with mean altitude of 1.25 km shows its lowest frequency during the night, and a factor of two or higher in early afternoon hours. The cloud fraction above 3 km altitude shows almost opposite trends then low levels clouds. Liquid water path of low levels clouds shows similar pattern to low level cloud fraction with minima in morning and maxima in the early afternoon hours. The robust diurnal variation in cloud fraction and frequency from ground and space based remote sensing methods is an indication of surface coupling with local boundary layer meteorology. In this study, we focus on case studies of low-level cloud properties. Multiple sets of observations over the SGP site are compared, e.g. (a) ARM Raman Lidar observations, (b) ARM aircraft observation from HI-SCALE , and (c) satellite observations from GOES, MODIS, and microwave satellite-based retrievals. Considering the large spatial variations in cloud properties as a result of surface coupling, the MODIS and GOES cloud properties at 1 or 5 km pixel resolutions will be used over 25, 50, 100 and 200 km domains around the SGP site. The spatial representativeness of shallow cloud properties measured at the ARM site will also be examined.