CATS Near Real Time Data Products and Applications for Data Assimilation

In February 2015, the NASA Cloud-Aerosol Transport System (CATS) backscatter lidar began operation on the International Space Station (ISS) as a technology demonstration for future Earth Science Missions.  CATS has continued operation through the present, providing vertical measurements of cloud and aerosols properties.  Owing to its location on the ISS, a cornerstone technology demonstration of CATS is the capability to acquire, process, and disseminate near-real time (NRT) data within 6 hours of observation time.  Here, we present CATS NRT data products and outline CATS algorithms used to discriminate clouds from aerosols, and subsequently identify aerosol type.  CATS NRT data has several applications, including providing notification of hazardous events for air traffic control and air quality advisories, field campaign flight planning, as well as a data source for constraining cloud and aerosol distributions in via data assimilation in aerosol transport models. 

Recent developments in aerosol data assimilation techniques have permitted the assimilation of aerosol optical thickness (AOT), a 2-dimensional quantity that is reflective of the simulated aerosol loading in aerosol transport models.  While this capability has greatly improved simulated AOT forecasts, the vertical position, a key control on aerosol transport, is often not affected in simulated aerosol plumes.  Here, we also present preliminary efforts to utilize CATS NRT data as a data assimilation input to the NASA Goddard Earth Observing System version 5 (GEOS-5) atmospheric general circulation model and assimilation system using an Ensemble Kalman Filter (EnKF) approach, demonstrating the utility of CATS for future Earth Science Missions.