RapidScat backscatter measurement validation

Alsabah, Ruaa; Al-Sabbagh, Ali; Zec, Josko

doi:10.1117/1.jrs.12.034005

Cited by 2 publications

(1 citation statement)

References 17 publications

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“…Traditionally, scatterometers have been calibrated and validated against in situ buoys (Bentamy et al 2008;Pensieri et al 2010;Ribal and Young 2020b;Satheesan et al 2007;Verspeek et al 2008) and fixed platforms (Alsabah et al 2018;Madsen and Long 2016;Ribal and Young 2020b). As ''ground truth,'' both buoys and platforms have limitations, particularly at high wind speeds.…”

Section: Introductionmentioning

confidence: 99%

Calibration of scatterometer wind speed under hurricane conditions

Ribal

Tamizi

Young

2021

Journal of Atmospheric and Oceanic Technology

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Four scatterometers, namely: METOP-A, METOP-B, ERS-2 and OCEANSAT-2 were re-calibrated against combined National Data Buoy Center (NDBC) data and aircraft Stepped Frequency Microwave Radiometer (SFMR) data from hurricanes. As a result, continuous calibration relations over the wind speed range 0 to 45 ms-1 were developed. The calibration process uses match-up criteria of 50 km and 30 min for the buoy data. However, due to the strong spatio-temporal wind speed gradients in hurricanes, a method which considers both scatterometer and SFMR data in a storm-centred translating frame of reference is adopted. The results show that although the scatterometer radar cross-section is degraded at high wind speeds, it is still possible to recover wind speed data using the re-calibration process. Data validation between the scatterometers shows that the calibration relations produce consistent results across all scatterometers and reduce the bias and root mean square error compared to previous calibrations. In addition, the results extend the useful range of scatterometer measurements to as high as 45 ms-1.

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Section: Introductionmentioning

confidence: 99%

Calibration of scatterometer wind speed under hurricane conditions

Ribal

Tamizi

Young

2021

Journal of Atmospheric and Oceanic Technology

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Calibration and Cross Validation of Global Ocean Wind Speed Based on Scatterometer Observations

Ribal

Young

2020

Journal of Atmospheric and Oceanic Technology

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Global ocean wind speed observed from seven different scatterometers, namely, ERS-1, ERS-2, QuikSCAT, MetOp-A, OceanSat-2, MetOp-B, and Rapid Scatterometer (RapidScat) were calibrated against National Data Buoy Center (NDBC) data to form a consistent long-term database of wind speed and direction. Each scatterometer was calibrated independently against NDBC buoy data and then cross validation between scatterometers was performed. The total duration of all scatterometer data is approximately 27 years, from 1992 until 2018. For calibration purposes, only buoys that are greater than 50 km offshore were used. Moreover, only scatterometer data within 50 km of the buoy and for which the overpass occurred within 30 min of the buoy recording data were considered as a “matchup.” To carry out the calibration, reduced major axis (RMA) regression has been applied where the regression minimizes the size of the triangle formed by the vertical and horizontal offsets of the data point from the regression line and the line itself. Differences between scatterometer and buoy data as a function of time were investigated for long-term stability. In addition, cross validation between scatterometers and independent altimeters was also performed for consistency. The performance of the scatterometers at high wind speeds was examined against buoy and platform measurements using quantile–quantile (Q–Q) plots. Where necessary, corrections were applied to ensure scatterometer data agreed with the in situ wind speed for high wind speeds. The resulting combined dataset is believed to be unique, representing the first long-duration multimission scatterometer dataset consistently calibrated, validated and quality controlled.

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RapidScat backscatter measurement validation

Cited by 2 publications

References 17 publications

Calibration of scatterometer wind speed under hurricane conditions

Calibration of scatterometer wind speed under hurricane conditions

Calibration and Cross Validation of Global Ocean Wind Speed Based on Scatterometer Observations

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