Fortran, Python, and Satellite Data Assimilation: New Tools for the GEOS-5 Atmospheric Data Assimilation System and Lessons from their Development

At the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center, a new tool, Focapy, has been developed for generating a Python interface to Fortran. This generator, written in Python, provides an entirely new way of interfacing Python with native Fortran code. This presentation will discuss the challenges of interfacing Fortran with Python, provide insight to the process of generating a Python interface within the generator, and ultimately present the results from using this tool in production.

We also have developed a post-processing tool, PyRadmon, to aid in the monitoring of satellite radiance measurements. The tool, completely written in Python, is designed to enumerate, process, and plot details and statistics of the satellite measurements, while providing a substantial speed boost over its predecessor. The increase in speed is becoming more and more significant as the current GEOS-5 system is now actively and routinely assimilating over 5 million observations every six hours. This talk presents the tool and discusses various challenges and lessons learned from developing the Python radiance monitoring tool, including lessons on modular design and optimization.