Validation of an Airborne Doppler Wind Lidar in Tropical Cyclones.

Lisa R Bucci,Robert Atlas,Jun A Zhang,G David Emmitt,Kelly Ryan,Christopher O’Handley

doi:10.3390/s18124288

Abstract

This study presents wind observations from an airborne Doppler Wind Lidar (ADWL) in 2016 tropical cyclones (TC). A description of ADWL measurement collection and quality control methods is introduced for the use in a TC environment. Validation against different instrumentation on-board the National Oceanographic and Atmospheric Administration’s WP-3D aircraft shows good agreement of the retrieved ADWL measured wind speed and direction. Measurements taken from instruments such as the global positioning system dropsonde, flight-level wind probe, tail Doppler radar, and Stepped Frequency Microwave Radiometer are compared to ADWL observations by creating paired datasets. These paired observations represent independent measurements of the same observation space through a variety of mapping techniques that account for differences in measurement procedure. Despite high correlation values, outliers are identified and discussed in detail. The errors between paired observations appear to be caused by differences in the ability to capture various length scales, which directly relate to certain regions in a TC regime. In validating these datasets and providing evidence that shows the mitigation of gaps in 3-dimensional wind representation, the unique wind observations collected via ADWL have significant potential to impact numerical weather prediction of TCs.

Highlights

While meteorological observations have improved in both quality and density, there remain important data-sparse regions in tropical cyclones (TCs)
The current study looks at scanning coherent 1.6-μm airborne Doppler Wind Lidar (ADWL) that was operated during the 2015 and 2016 Atlantic hurricane seasons onboard NOAA’s Lockheed WP-3D Orion (P-3)
The purpose of this study is threefold: (1) to show ADWL technology is capable of collecting frequent observations within a TC; (2) to establish an independent validation of the ADWL winds between 5 m s−1 and 40 m s−1 in a TC environment using multiple instruments; and (3) to demonstrate that the ADWL is a useful tool for observing the wind field in regions without clouds or with broken optically thick clouds

Summary

Introduction

While meteorological observations have improved in both quality and density, there remain important data-sparse regions in tropical cyclones (TCs). These regions include the boundary layer [1,2,3] and precipitation free areas, such as moats between the eyewall and outer rainbands or the eyewall and secondary eyewall [4]. Satellite capabilities allow remote sensing of the marine atmosphere, but the availability of remotely-sensed wind observations in and near a TC is limited. Advanced Scatterometer (ASCAT) and Scatterometer Satellite-1 (SCATSAT-1), both space-based polar orbiting scatterometers, occasionally measure a snapshot of the surface wind speeds during a coincidental TC overpass. Scatterometers tend not to accurately retrieve hurricane force wind speeds because the signal used

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Conclusion