HAPpy Hour Seminar - Cloud distributions over CONUS in recent two decades

Clouds have tremendous impacts on the Earth’s radiation budget as well as the hydrological cycle. Understanding cloud distributions in recent decades helps us get a deeper understanding of the critical mechanisms causing their changes. The statistical analysis was conducted based on 2-decadal satellite observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and long-term convection-permitting simulation (CONUS404) to understand the uncertainties of cloud products and identify the critical mechanism leading to such observed patterns and/or to infer model deficiencies for future improvement of climate models. The preliminary results unveiled consistent seasonal trends of MODIS and CONUS404 cloud distributions, yet, clouds seem to be underestimated in CONUS404 simulation. Regional analysis across CONUS shows that cloud dissimilarities are different across regions, which indicates the potential impacts of terrain, geographical locations, and climate background on such observed differences. 

Cloud climatological analysis was also conducted based on CONUS404 for different cloud types, from low-middle-high clouds to precipitating and non-precipitating clouds.

Overall, clouds are found  most frequently in the cold season (i.e., February), and peaks at around 12 UTC. In the summertime, an earlier peak of clouds is simulated at around 10 - 11 UTC. Similar seasonal trends are identified for precipitating clouds, yet, a double-peak of precipitating clouds are found in the summertime (i.e., July). 

Future research will include satellite products with more detailed diurnal representation (i.e., GOES-16) to enhance the robustness of the study, and further identify the underlying mechanisms/factors causing such dynamic cloud patterns. Closer look at CONUS clouds over cities, the physical mechanisms of cloud and precipitation forming processes over cities and the relationship with city properties will be further exploited. The expected outcome can be used to support the city planning in the spirit of building more sustainable living conditions.