华东地区钻孔体应变对飑线天气过程响应的特征与机制

2018年3月4日华东地区爆发了一次强飑线天气过程, 为揭示过境区域钻孔体应变对该飑线生命史期间的响应特征与机制, 本文结合多普勒天气雷达和地面气象站数据, 系统分析了南昌、 黄山、 湖州和岱山等4个钻孔体应变台的观测记录。 结果表明: ① 飑线过境时的气压突变是引起体应变显著变化的主因, 由此引起最大的体应变量为16.2×10^-9; ② 气压涌升幅度与体应变的弹性压缩量具有较好的线性关系, 两者变化的周期较一致, 为26~74 min, 而气压影响系数高达5.0×10^-9/hPa; ③ 各台对飑线的响应能力较好, 而且在时间、 空间和强度上, 体应变变化能较好地呈现飑线的演变过程和传播特征。 以上结果, 不仅有助于科学识别飑线所引起单台或多台体应变异常变化的物理本质; 还能为短周期气压效应的改正模型提供实证依据。

Characteristics and Mechanism of Borehole Strainmeter in Response to a Squall Line in East China

On 4 March 2018, a southwest-northeast-oriented squall line was observed propagating across East China, which caused disaster during its evolution. The main object of this work is to systematically reveal the characteristics of the squall line in strainmeter measurements, and to improve our understanding of atmospheric loading signals in strainmeter records during the passage of the mesoscale convective system. Combined with the doppler radar, atmospheric pressure and outdoor temperature observations, we analyze the responses of volumetric strain with 1-minute resolution to the strong squall line recorded at Nanchang, Huangshan, Huzhou, and Daishan stations. The results show that: ① The short-period jump in the atmospheric pressure caused by the squall line is the main dominating driving force for the pressure-induced volumetric strain, the maximum magnitude is about 16.2×10^-9 on strain records. ② It is also observed the relationship between the fluctuations of atmospheric pressure and the compressive strains as for the magnitudes for the above-mentioned stations show a good linear variations. And the observed fluctuations with a periodicities ranging from 26 to 74 minutes are almost consistent between the atmospheric pressure and volumetric strain. Moreover, the atmospheric pressure coefficient of volumetric strain can reach up to 5.0×10^-9/hPa. ③ All the stations can respond well to the squall line. Furthermore, the evolution process and propagating pattern of the spatiotemporal and intensity variations for the squall line can be revealed clearly by multi-station records. The results could lead to reasonably uncover the physical origin of anomalous volumetric strain changes recorded at single-and/or multi-station. Meanwhile, the results can also contribute to providing the crucial observational evidences for atmospheric loading model in short period aiming to correct barometric effect precisely.