Radar Echo Tracking of Icing-Relevant Features

TheTerminal Area Icing Weather Information for NextGen (TAIWIN) Capability is being developed to detect and predict icing conditions within and around airport terminal areas. One goal of the TAIWIN development is to implement a nowcasting capability that would produce 15 minute to 2-hour forecasts based on a combination of current and forecast conditions. One potential element of the nowcast capability is computing the advection and/or tracking of icing-relevant features in current observations forward in time. The goal of this research is to compute the advection of icing conditions to enable nowcasting within the TAIWIN Capability.

There are several established techniques to compute the advection of radar echoes including correlation tracking. It is well documented that correlation tracking programs work well in convective situations in which there are many well defined features that can be used to compute correlations from one time to the next. It is not clear how well these correlation trackers will work in more homogeneous, stratiform and light precipitation situations commonly associated with icing conditions. In this study we adapt the existing NCAR correlation tracking and advection algorithms, CTREC and GridForecast, to wintertime radar echoes and evaluate the advection forecasts. Further, we consider fields other than radar reflectivity to input into the correlation tracking algorithm to determine if they are skillful and could be used as part of TAIWIN’s Nowcast Capability. These fields include intermediate and final icing diagnostic fields from the TAIWIN Diagnostic Capability.

The correlation tracking advection forecasts will be compared to advection forecasts using model wind forecasts. A blended solution that combines radar-based advection fields with similar fields from satellite, as well as model grids and persistence fields may be explored in the future.

This paper will present a progress report on developing an advection forecast in wintertime icing conditions.

This research is in response to requirements and funding by the Federal Aviation Administration (FAA). The views expressed are those of the authors and do not necessarily represent the official policy or position of the FAA.