Evaluation of Winds from SCATSAT-1 and ASCAT Using Buoys in the Indian Ocean
2021
Modi, Anuradha | Munaka, Suresh Kumar | Harikumar, R. | Nair, T. M Balakrishnan | Srinivas, K.
Over the data sparse oceanic region, ocean surface winds from scatterometers on-board satellites play a crucial role to make accurate Numerical Weather Prediction model-based analysis. In the present study, ocean surface winds derived from the recently launched SCATSAT-1 for the year 2017 over the Indian Ocean are validated against the winds from the Moored and RAMA buoys. The validation results for ASCAT winds for the same period are also presented. The comparison of SCATSAT-1 (ASCAT) winds against offshore OMNI buoy winds indicates that the mean differences for wind speed and wind direction are 0.5 m/s and – 1.0° (0.39 m/s and – 4.0°), and the RMSEs are 1.44 m/s and 23.0° (1.17 m/s and 25.0°), respectively. For the coastal OMNI buoys, the SCATSAT-1 (ASCAT) indicated that the mean differences for wind speed and wind direction are 1.6 m/s and – 5° (1.15 m/s and – 0.4°), and the RMSEs are 2.65 m/s and 46 deg, (2.1 m/s and 51°), respectively. Quantified differences are almost similar for the comparison of SCATSAT-1/ASCAT with RAMA buoys. Overall, the quantified differences in the wind speed and direction between the SCATSAT-1 and buoys are closer to the satellite’s mission specifications of 1.8 m/s and 20°, respectively, and at par with the ASCAT accuracies. The capability of SCATSAT-1 winds to capture a cyclonic storm OCKHI during December 2017 also is depicted. The present study endorses that the SCATSAT-1 data are accurate and reliable and can be used in Numerical Weather Prediction (NWP) models and also for other applications.
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