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A SAR Observation and Numerical Study on Ocean Surface Imprints of Atmospheric Vortex Streets
IMSG at NOAA/NESDIS E/RA3, WWBG, Room 102, 5200 Auth Road, Camp Springs, MD 20746-4304, USA
NOAA/NCEP/EMC, 5200 Auth Road, Camp Spring, MD 20706, USA
Center for Satellite Applications and Research, NOAA/NESDIS, Camp Springs, MD 20746, USA
* Author to whom correspondence should be addressed.
Received: 31 March 2008; Accepted: 19 May 2008 / Published: 21 May 2008
Abstract: The sea surface imprints of Atmospheric Vortex Street (AVS) off Aleutian Volcanic Islands, Alaska were observed in two RADARSAT-1 Synthetic Aperture Radar (SAR) images separated by about 11 hours. In both images, three pairs of distinctive vortices shedding in the lee side of two volcanic mountains can be clearly seen. The length and width of the vortex street are about 60-70 km and 20 km, respectively. Although the AVS’s in the two SAR images have similar shapes, the structure of vortices within the AVS is highly asymmetrical. The sea surface wind speed is estimated from the SAR images with wind direction input from Navy NOGAPS model. In this paper we present a complete MM5 model simulation of the observed AVS. The surface wind simulated from the MM5 model is in good agreement with SAR-derived wind. The vortex shedding rate calculated from the model run is about 1 hour and 50 minutes. Other basic characteristics of the AVS including propagation speed of the vortex, Strouhal and Reynolds numbers favorable for AVS generation are also derived. The wind associated with AVS modifies the cloud structure in the marine atmospheric boundary layer. The AVS cloud pattern is also observed on a MODIS visible band image taken between the two RADARSAT SAR images. An ENVISAT advance SAR image taken 4 hours after the second RADARSAT SAR image shows that the AVS has almost vanished.
Keywords: Remote Sensing; Ocean; SAR; RADARSAT; MODIS; AVS; NOGAPS
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MDPI and ACS Style
Li, X.; Zheng, W.; Zou, C.-Z.; Pichel, W.G. A SAR Observation and Numerical Study on Ocean Surface Imprints of Atmospheric Vortex Streets. Sensors 2008, 8, 3321-3334.
Li X, Zheng W, Zou C-Z, Pichel WG. A SAR Observation and Numerical Study on Ocean Surface Imprints of Atmospheric Vortex Streets. Sensors. 2008; 8(5):3321-3334.
Li, Xiaofeng; Zheng, Weizhong; Zou, Cheng-Zhi; Pichel, William G. 2008. "A SAR Observation and Numerical Study on Ocean Surface Imprints of Atmospheric Vortex Streets." Sensors 8, no. 5: 3321-3334.