Macro-physical Properties of Shallow Cumulus Clouds at the ARM SGP site: Enhanced Ground-Based Observations from the Total Sky Imager
Poster PDF
Authors
Jessica M Kleiss — Lewis and Clark College
Erin Allegra Riley — Lewis and Clark College
Chuck N. Long (deceased) — NOAA- Earth System Research Laboratory
Laura Dian Riihimaki — CIRES | NOAA ESRL GML
Larry Berg — Pacific Northwest National Laboratory
Victor R. Morris — Pacific Northwest National Laboratory
Evgueni Kassianov — Pacific Northwest National Laboratory
Category
Warm low clouds, including aerosol interactions
Description
Information about shallow cumulus clouds fields derived from active ground-based observations can have limited sampling statistics (~10 clouds per hour) because of the narrow fields of view (FOV) associated with zenith-pointing radar and lidar. Routine satellite observations do not have sufficient spatial resolution to observe small (<1 km) clouds and lack temporal continuity. Observations of shallow cumulus clouds are needed for comparison with the high-frequency and high-resolution output of the Large Eddy Simulation ARM Symbiotic Simulation and Observation (LASSO) project and for evaluating cumulus parameterizations. We evaluate macro-physical cloud properties of shallow cumulus clouds derived primarily from the Total Sky Imager (TSI). The hemispherical FOV of the TSI captures multiple clouds frequently (every 30s). This capability has not yet been fully utilized to report on the statistics of shallow cumulus clouds fields. We present new findings on cloud area statistics and areal-averaged cloud aspect ratio. We use a curated dataset collected at the Southern Great Plains (SGP) site including single-layer shallow cumulus times identified by the new shallow cumulus value-added product (VAP), satellite observations, active remote sensing of clouds (ARSCL) VAP, and TSI-derived cloud field uniformity metric. Times are selected to optimize comparisons between instruments with different FOV. We discuss the new findings and curated dataset and their relevance for the expected model evaluations of the LASSO project for 2017. In comparison with available TSI data, the enhanced near continuous multi-year (2000-2017) TSI observations represent an improved climatology of shallow cumulus clouds at the ARM SGP site.
