Visualizing Cold Air Aloft with Radio Occultation and Hyperspectral Infrared Sounders: Investigating Aviation Safety Purposes

Cold air temperatures located at jet cruising altitudes are an aviation safety concern, as jet fuel can gelify when exposed to extreme cold temperatures. Meteorologists of the National Weather Service (NWS) Center Weather Service Unit (CWSU) in Anchorage, Alaska are responsible for assisting in the provision of weather information to air traffic controllers who overlook regions of AK and the Arctic Ocean. While forecast models are used as prediction tools for such ‘cold air events', the forecasts are not always accurate or timely enough. Additionally, real-time observations available to forecasters are limited to the sparse radiosonde network and isolated aircraft reports. A desire and need for 3-D real-time observations has been made known by forecasters so that they can better issue pilot advisories.

Collaboration on this cold air aloft issue is currently ongoing between the AK NWS office and researchers from GINA, SPoRT, CIRA, and CIMSS under a newly funded proposal that is part of the JPSS proving ground and risk reduction (PGRR) activities. This initiative aims to develop visualization tools of 3-D temperatures fields from real-time hyperspectral infrared (IR) sounder retrievals (Stevens et al., 2015; Smith et al., 2015; Weisz et al., 2015). This work presents the potential to use radio occultation (RO) data to supplement and add information to the IR sounder and radiosondes. The high vertical resolution of RO and its quality of being most accurate in the upper troposphere and lower stratosphere make it a good candidate for detecting the cold air's vertical extent. Visualizations are made using near real-time GRAS RO data from EUMETSATs ROMSAF and CrIS Dual Regression products obtained from GINA using the direct broadcast capability on Suomi-NPP and the product applications available through the Community Satellite Processing Package (CSPP) project.