Use of FAA NextGen Weather to Meet Terminal ATC Weather Needs

Air traffic controllers at Terminal Radar Approach Control (TRACON) locations need access to timely, accurate and reliable weather information in their areas of responsibility. Weather data from Air Surveillance Radars (ASRs) currently is used as the source of 6-level precipitation information for terminal air traffic controllers’ displays – the modernized STARS system (Standard Terminal Automation Replacement Systems). With a 28-sec update rate, the connected ASR provides a timely source of precipitation for the area of concern. However, the ASR weather data are subject to various artifacts such as a large cone-of-silence preventing detection of storms directly overhead, anomalous propagation (AP) giving rise to storm-like clutter returns, and artificial broadening and weakening of the storms due to the inherently wide fan beam of surveillance radars.

There are some large terminals where higher quality precipitation intensity and supplemental information is available, but not on the terminal controllers’ scopes. Integrated Terminal Weather System (ITWS) terminals have a separate situation display where precipitation intensity from a single ASR or a mosaic of multiple ASRs can be shown, with AP detected and filtered out by integrating other weather information such as pencil-beam NEXRAD and Terminal Doppler Weather Radar (TDWR) data. In addition, ITWS provides supplemental weather information such as long range radar mosaics (beyond the 60 nmi range of a single ASR), storm cell information such as storm motion and echo tops, airport lightning warnings and especially safety-critical detections of microburst wind shear impacting the runways. ASR-9 Weather Systems Processor (WSP) terminals have single ASRs with their own Doppler-derived wind shear detections, but - as with ITWS terminals - none of the advanced weather products are shown on STARS.

The future NextGen Weather Processor (NWP) offers an excellent opportunity to improve real-time weather information for terminal Air Traffic Control (ATC). Internally, NWP processing of radar mosaics runs at a 25 sec update rate, driven by requirements for rapidly updating layer mosaics on the En Route Automation Modernization (ERAM). The NEXRAD and TDWR radar source data are processed in volumes that update with each new sweep received, and are mosaicked together and quality-controlled for clutter and other artifacts, every 25 sec. Canadian radar data is also included. These internal NWP Mosaics are ideally aligned with the ASR scan rate and NWP already creates specially adapted terminal slices of national mosaics (e.g., Base Reflectivity per TRACON).

In this paper, we provide the first look at a blended NWP – ASR terminal precipitation mosaic, using terminal slices of the internal 25-sec NWP Vertically Integrated Liquid (VIL) precipitation mosaic combined with the local ASR precip (mosaic). The true ASR rapid update provides a low latency detection of new storm growth, while the NWP mosaic provides improved storm data quality and coverage (both longer range and directly above the ASRs). This paper will also highlight benefits of providing supplemental weather information on STARS, in addition to improved precipitation maps, to better meet Terminal ATC weather needs.

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This material is based upon work supported by the Federal Aviation Administration under Air Force Contract No. FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Federal Aviation Administration.