Observing System Simulation Experiments (OSSEs) are modeling studies that could be used for:
- Optimal design of observation systems
- Evaluation of potential benefits of new observing system data in context of exiting observations for a given data assimilation system and numerical weather prediction
The underlying data assimilation systems, and identification of areas of improvement from both observation systems and data assimilation systems. An OSSE can be performed prior to the development of the new observing system, so that the results of the study may help to guide the design and implementation of the new system. There is no other way helping NOAA to evaluate the cost effective observation systems. In order to support future NOAA operations, an OSSE could play critical role in NOAA-OAR research, identifying future observation systems and data assimilation systems for improvement.
OSSE is a complex system and requires expertise and resource to build and develop and evaluate. In the past year, as part of a collaborative Joint OSSE between many different institutions, an OSSE framework has been developed and implemented at the National Oceanographic and Atmospheric Administration (NOAA) Earth Systems Research Laboratory (ESRL) in support of the NOAA Unmanned Aircraft Systems (UAS) Program. This Joint OSSE was initiated to share resources for the creation of an updated OSSE system following the previous global OSSE effort developed in the 1990s (Atlas 1985,1997, 2008, 2010, and Masutani et al. 2006). Great effort and resources have been invested in building this joint OSSE system by the NOAA UAS program support for ESRL and AOML, including its calibration (ESRL has spent 4+ years), nature run evaluation (NASA, NCEP and ESRL), and synthetic observation generation (NASA/GMAO and NCEP/EMC).
A first time ever UAS OSSE report on hurricane track has been delivered to the NOAA UAS program office (Dr. Robbie Hood).
Our plan of NOAA-OAR OSSE system is to build an OSSE or OSSEs helping NOAA to evaluate all potential future observation systems for all weather applications and identify improvement of data assimilation and forecast system.
To build a future NOAA-OAR OSSE system, one nature run, one data assimilation system and one forecast system are not sufficient. Various applications of the future OSSE system require multiple nature runs, multiple data assimilation systems and forecast systems to be implemented and calibrated. For some other applications, such as convective initiation, hurricane intensity and etc., a global OSSE system may not be realistic and a regional OSSE system is necessary. For such a complex system, a careful planning is essential for success. In this plan, we emphasize on the OSSE attributes and merge the global and regional OSSE issues under these attributes.