The Turbulence Algorithm Intercomparison Exercise: Statistical Verification Results

Abstract

This paper summarizes results of a winter 1998-99 intercomparison of the forecasting capability of a number of clear-air turbulence (CAT) forecasting algorithms. This study was undertaken by the Turbulence Product Development Team (PDT) of the Federal Aviation Administration’s (FAA’s) Aviation Weather Research Program (AWRP). Purposes of the intercomparison were to (i) develop a baseline for the quality of current CAT forecasting algorithms; (ii) demonstrate to-date progress in the development of these forecasting tools; (iii) examine the strengths and weaknesses of the algorithms; and (iv) perform an evaluation that is independent, consistent, comprehensive, and fair. Implementation of the intercomparison and analyses of the results were the responsibility of the AWRP Quality Assessment Group, which includes the verification groups of the NOAA Forecast Systems Laboratory (FSL) and the National Center for Atmospheric Research, Research Applications Program (NCAR/RAP). The study consisted of two major components: (i) a real-time component, in which the algorithms were evaluated in near-real-time by FSL’s Real-Time Verification System (RTVS; Mahoney et al. 1997), with results displayed on the World-Wide Web; and (ii) a post-analysis component in which the forecasts were regenerated and examined in detail at NCAR and FSL. This paper primarily concerns some results of the postanalyses. However, example results from the RTVS evaluation for winter 2000 are shown in the final section. The paper is organized as follows. The study approach is presented in Section 2. Section 3 briefly describes the algorithms that were included in the evaluation. The data that were utilized are discussed in Section 4, and the verification methods are described in Section 5. Some results of the study are presented in Section 6. Finally, Section 7 contains conclusions and future work.