由热带气旋MATTHEW引起的非潮汐负荷效应影响

热带气旋能在短期内造成海水和大气质量的重新分布,使得近海地表受力发生变化,进而产生非潮汐负荷形变,对现今高精度大地测量的影响已不容忽视.为了保证空间大地测量结果的精度和稳定性,热带气旋引起的地表形变必须进行有效的估计.因此本文联合NOS、GLOSS验潮站数据与海潮模型,通过获取非潮汐残余量分析了热带气旋“MATTHEW”引起的风暴潮.利用ECCO海洋环流模型、ERAin大气再分析模型、HUGO-m海洋动力学模型,分别估计了“MATTHEW”引起非潮汐海洋负荷、非潮汐大气负荷、动力学响应下非潮汐海洋负荷对地表位移的影响,结果表明热带气旋影响下的广大区域地表都不同程度受到非潮汐负荷的作用,最大位移分别达到-9.13 mm、3.31 mm、-6.11 mm,并且加入动力学响应的非潮汐海洋负荷要普遍大于IB(Inverted Barometer)响应下的结果.在对比不同位置站点所受负荷差异时,发现“大陆站”非潮汐海洋负荷形变普遍大于“岛屿站”,而“岛屿站”更易受非潮汐大气负荷的影响.

The non-tidal loading induced by tropical cyclones MATTHEW

Tropical cyclones can cause sea water and atmospheric mass redistribution in a short term, which induces surface deformation from non-tidal ocean loading because of the surface force change. We combine tide gauge data from NOS and GLOSS stations with ocean tide model, and analyze storm surge arising from tropical cyclones MATTHEW by calculating the non-tidal residuals. Based on Circulation and Climate of the Oceans model, ERAin atmospheric reanalysis model and Toulouse Unstructured Grid Ocean model, we estimate the surface deformation from non-tidal ocean loading (NTOL), non-tidal atmospheric pressure loading (NTAL) and dynamic non-tidal ocean loading (D-NTOL). Results show that offshore areas are affected by MATTHEW to a greater or lesser degree. The predicted maximum displacements are -9.13 mm, 3.31 mm and -6.11 mm caused by NTOL, NTAL and D-NTOL respectively. Taking into account the dynamic response, results in the non-tidal ocean loading displacements are larger than those in inverted barometer hypothesis. When comparing loading displacements differences, we can draw the conclusion that non-tidal ocean loading displacements of continent sites are universally larger than those in islands sites, while non-tidal atmospheric pressure loading has an opposite result:loading displacements of continent sites are generally smaller than those in island sites.