Fostering the Need of L-Band Radiometer for Extreme Oceanic Wind Research

Ocean surface winds from space-borne radiometers and scatterometers are crucial inputs for numerical models for the operational weather and oceanic sea state forecasts. The rainfall, associated mainly with deep convective clouds, influences the wind retrievals from these sensors during extreme winds conditions (higher than 30 m
$\text{s}^{-1}$
), as the signal strongly gets affected by the intervening atmosphere, mainly the precipitation. This study emphasizes the importance of the winds from L-band radiometric measurements from Soil Moisture Active Passive (SMAP) satellite compared to the operational Advanced Scatterometer (ASCAT) (C-band) and SCATSAT-1 (Ku-band) scatterometers, National Centers for Environmental Prediction (NCEP) final analysis, and European Centre for Medium-Range Weather Forecasts reanalysis 5 (ERA5) reanalysis wind products. Investigation at global scale suggests that except SMAP, no other selected data are able to capture wind speed more than 56 m
$\text{s}^{-1}$
, and large underestimations are found in presently available scatterometers and reanalysis. These high wind speed errors are more prominent when verified with Joint Typhoon Warning Center (JTWC) best track data for global storms. Moreover, the high winds near storms from scatterometers are generally flagged as rainy pixels and not used for operational applications. These limitations of capturing high winds in scatterometers have been addressed here using histogram corrections approach using SMAP retrieved winds. Moreover, the regional model simulations for a case study suggest that the modified scatterometer winds have larger impact on tropical storm prediction mainly on track and intensity.