Development of NASA's integrated Instrument Simulator Suite for Atmospheric Remote Sensing from

Retrieval, interpretation, and use in data assimilation schemes of measurements obtained by remote sensing instruments is unavoidably affected by the assumptions and methods adopted in the forward modeling of such instruments. Recognizing this need, several teams have initiated the development of advanced instrument simulators capable of reproducing the measurements of not one, but a set of instruments. Among them we find ECSIM, SDSU, COSP, and others.

Each integrated instrument simulator includes a set of assumptions applied to geophysical parameters not explicitly resolved by the atmospheric model used as input, and a set of approximations and modeling parameterizations to model propagation in the atmosphere and instrument characteristics. In turn, these assumptions and approximations impact on any conclusions drawn from the simulated measurements.

The new Instrument Simulator Suite for Atmospheric Remote Sensing (ISSARS) is being developed to provide a computationally efficient and modular framework to integrate and test available algorithms and methods aiming at the forward modeling of radars, lidars, radiometers, polarimeters and other real-aperture sensors currently employed on spaceborne platforms or planned for future missions.

This talk will provide a high level overview of the current activities in the U.S. pertaining the existing and planned spaceborne Cloud Profiling Radars, namely, the one currently flying on CloudSat and the one planned for deployment on the Aerosol/Cloud/Ecosystems (ACE) mission, and of the specific role of ISSARS within this framework. We will also focus on the radar component of ISSARS and the development of the related modules, including modeling of multiple-scattering effects on Doppler radar measurements from space and multi-frequency sea surface backscattering characterization.