An improved wind retrieval algorithm for the HY-2A scatterometer -- Journal of Oceanology and Limnology,2015,33(5):1201-1209

	Cite this paper:
	WANG Zhixiong, ZHAO Chaofang, ZOU Juhong, XIE Xuetong, ZHANG Yi, LIN Mingsen. An improved wind retrieval algorithm for the HY-2A scatterometer[J]. Journal of Oceanology and Limnology, 2015, 33(5): 1201-1209

An improved wind retrieval algorithm for the HY-2A scatterometer

WANG Zhixiong^1,2, ZHAO Chaofang¹, ZOU Juhong², XIE Xuetong³, ZHANG Yi², LIN Mingsen²

1 Ocean Remote Sensing Institute, Ocean University of China, Qingdao 266100, China;
2 National Satellite Ocean Application Service, State Oceanic Administration, Beijing 100081, China;
3 Guangzhou University, Guangzhou 510006, China

Abstract:

Since January 2012, the National Satellite Ocean Application Service has released operational wind products from the HY-2A scatterometer (HY2-SCAT), using the maximum-likelihood estimation (MLE) method with a median filter.However, the quality of the winds retrieved from HY2-SCAT depends on the sub-satellite cross-track location, and poor azimuth separation in the nadir region causes particularly low-quality wind products in this region.However, an improved scheme, i.e., a multiple solution scheme (MSS) with a two-dimensional variational analysis method (2DVAR), has been proposed by the Royal Netherlands Meteorological Institute to overcome such problems.The present study used the MSS in combination with a 2DVAR technique to retrieve wind data from HY2-SCAT observations.The parameter of the empirical probability function, used to indicate the probability of each ambiguous solution being the "true" wind, was estimated based on HY2-SCAT data, and the 2DVAR method used to remove ambiguity in the wind direction.A comparison between MSS and ECMWF winds showed larger deviations at both low wind speeds (below 4 m/s) and high wind speeds (above 17 m/s), whereas the wind direction exhibited lower bias and good stability, even at high wind speeds greater than 24 m/s.The two HY2-SCAT wind data sets, retrieved by the standard MLE and the MSS procedures were compared with buoy observations.The RMS error of wind speed and direction were 1.3 m/s and 17.4°, and 1.3 m/s and 24.0° for the MSS and MLE wind data, respectively, indicating that MSS wind data had better agreement with the buoy data.Furthermore, the distributions of wind fields for a case study of typhoon Soulik were compared, which showed that MSS winds were spatially more consistent and meteorologically better balanced than MLE winds.

Received: 2014-06-11 Revised: 2014-07-25

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Articles by WANG Zhixiong

Articles by ZHAO Chaofang

Articles by ZOU Juhong

Articles by XIE Xuetong

Articles by ZHANG Yi

Articles by LIN Mingsen

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