HRD Seminar – Dr. Andrew Kren, CIMAS and AOML/HRD – 27 June 2018

Dr. Kren presented a seminar titled “Observing System Simulation Experiments (OSSEs) and Observing System Experiments (OSEs) to evaluate the impact of current and future observing systems in the NCEP GDAS”.


Observing System Experiments (OSEs) test the impact of current observing system platforms on analyses and forecasts, while Observing System Simulation Experiments (OSSEs) can evaluate the potential benefit of new observations prior to being assimilated operationally. Both studies can provide guidance for future observing systems to increase numerical weather prediction skill. A series of OSSEs and OSEs have been performed using NCEP’s GDAS with and without several observing platforms, including the NASA Global Hawk (GH) UAS, as well as infrared, microwave, radio occultation, and atmospheric motion vector satellite observations. Results are presented both globally and regionally and examine both tropical cyclone errors and forecast error metrics of anomaly correlation, root-mean-squared error, and precipitation skill scores. As part of the Sensing Hazards with Operational Unmanned Technology (SHOUT) project between 2015-2016, OSSEs and OSEs were performed to evaluate the impact of the GH on forecasts of both winter storms and tropical cyclones. An OSSE was carried out prior to field missions to determine optimal flight patterns for the NASA GH, taking into account meteorological features, such as jet streaks, atmospheric rivers, frontal boundaries, and data-sensitive regions. OSEs as part of SHOUT were carried out on three extratropical systems in February 2016 and Hurricanes Matthew and Nicole in October 2016. Results indicate reduced track errors and a better representation of the low-level shear environment. The impact of infrared, microwave, radio occultation, and atmospheric motion vector satellite observations on tropical cyclone track and wind speed errors are also evaluated using statistics from 19 tropical cyclones that occurred between August and September 2016. Future work with the GH UAS is also discussed.

A recording of the presentation is available on the anonymous ftp site: