Implementing the VAHIRR algorithm on the NEXRAD ORPG and AWIPS

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Wednesday, 1 February 2006
Implementing the VAHIRR algorithm on the NEXRAD ORPG and AWIPS
Exhibit Hall A2 (Georgia World Congress Center)
Robert Gillen, ENSCO Inc., Cocoa Beach, FL; and F. J. Merceret and J. Miller

Poster PDF (164.3 kB)

Lightning LCC (LLCC) and Flight Rules are used for all launches and landings to avoid natural and triggered lightning strikes to space vehicles. Improved LLCC for anvil clouds, and an associated radar product called VAHIRR required by them, were developed using data collected by the Airborne Field Mill (ABFM) research program. Details of both the ABFM research program and the science behind the VAHIRR product are presented in other papers submitted to this conference.

VAHIRR stands for Vertically Averaged Height Integrated Radar Reflectivity. It is calculated at every horizontal position in the coverage area of the radar and can be displayed like standard two-dimensional reflectivity products such as composite reflectivity or echo tops. VAHIRR is the arithmetic product of two quantities not currently generated by the WSR-88D: a volume average of the reflectivity measured in dBZ and the average cloud thickness based on average echo top height and echo base height. Work has begun on implementing the VAHIRR algorithm as a radar product within the WSR-88D ORPG. Implementation of the algorithm within the ORPG will allow for continuous updates throughout the launch sequence and display on the standard NEXRAD radar console. The algorithm relies on all radar tilts of the reflectivity data within a volume scan to calculate the cloud thickness and average reflectivity values needed to compute the VAHIRR values. The paper will include a description of the implemented algorithm design and performance, sample output, concept of operations, and eventual transition to ORPG baseline for ingestion into AWIPS. Local customization to AWIPS is the only modification required for VAHIRR ingest.