Abstract:

Tropical Cyclone Radar Archive of Doppler Analyses with Re-centering (TC-RADAR) is a database containing deficiencies in software, coverage, and methodology for cases prior to 2010 that must be revisited. This pilot, multi-case project investigated: (1) reprocessing pre-2010 Major Hurricane cases using NOAA’s current automated airborne radar processing software to address deficiencies; and (2) comparing original and reprocessed analyses to previous literature and flight-level winds to TDR winds, to qualitatively and quantitatively note improvements in vertical wind motion and wind speed. In total, 13 tropical cyclone analyses were produced (10 were major or near-major hurricanes). Results show using current NOAA airborne radar processing software corrects pre-2010 deficiencies and improves winds in major hurricanes in terms of: reduced occurrence of anomalous vertical winds and wind speeds, peak (0.2%frequency) value (25-30%), and 99.9th percentile value (2-3 m/s). After reprocessing Major Hurricane Wilma, distributions between flight-level and TDR vertical velocity are in better agreement as anomalous vertical velocities are reduced in the TDR. Contoured Frequency by Altitude Diagrams (CFADs) containing all original analyses had its vertical winds reduced from approximately ± 6 m/s to ± 2 m/s in the reprocessed CFAD. At the 99.9th percentile for major hurricanes, results are similar to those in previous literature through 10 km, concluding that previous literature rightly excluded the pre-2010 deficient cases. Comparisons of TDR-based vertical velocity to flight-level instrument data with results of recent studies demonstrate that the reprocessed data is now suitable for research.

The results presented are from the NOAA Experiential Research and Training Opportunity (NERTO) graduate internship project conducted with NOAA mentor, Dr. Paul Reasor (OAR, AOML, HRD). This NERTO experience aligns with the NOAA Cooperative Science Center in CESSRST-II, supporting the Center’s goal of conducting NOAA mission-aligned collaborative research. This project, titled Revisiting Historical Airborne Radar Datasets, addressed the research question: how can software, coverage, and methodology deficiencies in TC-RADAR be addressed for pre-2010 Major Hurricane cases using NOAA’s current automated airborne radar processing software? The work provides value to the scientific community and program stakeholders by improving the processing of historical airborne reconnaissance radar datasets for research use that can be transitioned into National Weather Service operations to improve forecasts and ultimately increase weather-readiness. Through this internship, the student deepened their understanding of NOAA mission areas and gained enhanced skills in modifying and compiling airborne radar processing code, learning to critically assess the products derived from radar processing software, and communicating research results to mixed audiences within the NOAA community.