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潮汐椭圆和角度约束算法提高GOCI卫星数据海表流场反演精度

陈建   2019-07-03

      近日,我室硕士研究生陈建在国际知名期刊Journal of Geophysical Research: Oceans发表了关于提高GOCI卫星数据海表流场反演精度的相关论文。通讯作者为实验室陈建裕研究员。

      研究利用GOCI海洋水色(悬浮物浓度)遥感数据,基于最大相关系数(MCC)针对我国东海海域进行海表流场反演技术研究。在考虑潮流椭圆要素的基础上,结合漂流浮标轨迹图(Fig.1),提出了一种基于潮汐椭圆和角度约束的遥感反演海流矢量的改进方法,该算法主要从流场反演数据的角度出发,考虑矢量数据之间的关系,通过拟合偏转角度,从而进一步确定所在矢量组的基准矢量和基准旋转角;通过计算在确定基准矢量和基准旋转角后计算得到的其余矢量和实际观测矢量之间的角度差(Fig.2),对角度差进行排序,剔除角度差较大的矢量,保留合适的矢量。对反演数据进行角度约束算法后,试验案例中平均角度误差有明显的降低,降低了28%到38%。(Fig.3)。论文最后探讨了影响反演流场精度的因素,发现在不同的潮位下反演的精度存在差异。

引用:Chen, J., J. Chen, Z. Cao and Y. Shen. Improving Surface Current Estimation From Geostationary Ocean Color Imager Using Tidal Ellipse and Angular Limitation. Journal of Geophysical Research: Oceans, 124. https://doi.org/10.1029/2019JC015027

 

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Fig. 1 The daily surface vectors of the drifting buoy on 11 August 2013, with background distribution of GOCI-derived TSM. The red dashed ellipse is estimated from SSC vectors.

 

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Fig. 2 Illustration of direction judgement (a) and tidal ellipse-based fitting model (gray dashed arrows) for angular limitation calculation.

 

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Fig.3 Observed SSC vectors from drifting buoy (red arrows) and estimated from GOCI (blue arrows) on 7, 9, 10, 11, 12, and 13 August 2013, when the corresponding location in the GOCI image is cloud free and the satellite data were of high quality. The blue solid arrows remained under the angular limitation, and the dashed arrows indicate the spurious vectors.