Sea Surface Height Response to Tropical Cyclone from Satellite Altimeter Observations and SAR Estimates

• Published in: IEEE transactions on geoscience and remote sensing 2024-01, Vol.62, p.1-1
• Main Authors: Zhang, Biao, Wen, Liwen, Perrie, William, Kudryavtsev, Vladimir
• Format: Article
• Language: English
• Subjects: Altimeter; Altimeters; Altimetry; Anomalies; Cyclones; Decades; Empirical analysis; Estimates; Extreme weather; Height; Hurricanes; Ocean temperature; Oceans; SAR (radar); Satellite observation; Satellite tracking; Satellites; Sea surface; Sea surface height; Spatial distribution; Statistical analysis; Statistical methods; Storms; Stratification; Surface wind; Synthetic aperture radar; Synthetic Aperture Radar (SAR); Thermocline; Tropical cyclone; Tropical cyclones; Tropical environments; Weather; Wind; Wind fields; Wind speed
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2024.3371168

We present the characteristics of the sea surface height (SSH) response to tropical cyclones (TCs), based on a statistical analysis of long time series of satellite altimeter data. SSH anomalies on both along-and cross-track of TC are found to be dependent on storm intensity and translation velocity. Larger sea surface troughs correspond to the stronger and slower moving TCs. The most striking trough features are located in the vicinity of TC centers. The amplitudes of wedge-shaped troughs decay in the direction normal to the storm tracks. In extreme weather conditions, these troughs are primarily caused by the vertical displacement of isopycnals in the thermocline. For very strong and slow-moving TCs, the magnitude of the sea surface depressions can reach -21 cm. The spatial distribution of SSH anomalies tends to be asymmetric for faster moving TCs, comparing both sides of the TC tracks, becoming more symmetric for slower storms. The conventional altimeter has large gaps between tracks, especially in the tropics, which leads to the absence of SSH anomaly observations. To address this inherent limitation, we apply a semi-empirical model to estimate SSH anomalies, using TC and ocean stratification parameters. When applying the maximum wind speed and radius of the maximum wind derived from high-resolution synthetic aperture radar (SAR) gridded surface wind fields, the semi-empirical model estimates are in good overall agreement with collocated altimeter observations. These results suggest that indirect calculations of SSH anomalies may serve as an important complement for TC inner-core areas, when altimeter observations are not available.