杨小林,冯静,苏利娜,杨锦玲. 2024. 华北地区深井水位对飑线天气过程的水力响应. 地震学报,46(4):663−676. DOI: 10.11939/jass.20220214
引用本文: 杨小林,冯静,苏利娜,杨锦玲. 2024. 华北地区深井水位对飑线天气过程的水力响应. 地震学报,46(4):663−676. DOI: 10.11939/jass.20220214
Yang X L,Feng J,Su L N,Yang J L. 2024. Hydraulic responses of groundwater-level in deep wells to the passage of a squall line in North China. Acta Seismologica Sinica46(4):663−676. DOI: 10.11939/jass.20220214
Citation: Yang X L,Feng J,Su L N,Yang J L. 2024. Hydraulic responses of groundwater-level in deep wells to the passage of a squall line in North China. Acta Seismologica Sinica46(4):663−676. DOI: 10.11939/jass.20220214

华北地区深井水位对飑线天气过程的水力响应

Hydraulic responses of groundwater-level in deep wells to the passage of a squall line in North China

  • 摘要: 为探讨华北地区飑线天气对深井水位干扰的特征和影响机制,以2017年9月21日发生在华北中部的一次飑线事件为例,使用时频分析和线性回归等方法系统地诊断了此次飑线对无极、辛集、永清和宁晋等四口千米级深井的水位扰动特征。结果表明:在宏观层面,飑线过境各深井时会引起气压快速涌升,在气压的激励下,深井水位出现了即时的脉冲状波动,该干扰的持续时间可长达127 min;此次飑线过程中周期性气压波动的主频段为15—25 cpd,在该频段内,各深井水位与气压扰动的形态高度负相关,相关系数均低于−0.95,气压系数主要集中在−4.9—−6.9 mm/hPa之间。

     

    Abstract:
    Since the Mesozoic, the North China has experienced intensive seismic activity. Given its special seismo-tectonic background and unusually high level of seismic potential, a network of deep wells, primarily monitoring fault and crustal deformation precursors to destructive earthquakes, has been deployed in this area since late 1960s. Although these deep well-aquifer systems can effectively capture the tectonic transients, numerous spike-like signals associated with non-tectonic sources are always recorded in the groundwater levels; however, their physical mechanism have not been confirmed on a case-by-case basis up to now.
    The squall line is a common type of meso-scale convective system usually defined as a group of violent thunderstorms or storm cells arranged in the form of a narrow (a few tens of kilometers) or long (several hundreds of kilometers) line in a Doppler radar. Furthermore, the typical life-span of a squall line can last several hours, and its propagation speed is approximately 60 km/h. The surface area affected by squall line is typically accompanied by abrupt changes in surface pressure and air temperature.
    Squall lines occur with a high frequency in North China, but it is still unclear that how this kind of meso-scale severe weather disturbs the groundwater levels in deep wells. In view of the current situation, a target research is needed to reveal the features of hydraulic responses. On 21 September 2017, a squall line passed across the central North China, and significantly disturbed the groundwater levels in four wells deeper than 1 km, which are Wuji, Xinji, Yongqing, and Ningjin wells. Here we mainly adopt the spectrogram and linear regression methods to systematically examine the unique signals stimulated by this squall line. The results show that: ① From a macro perspective, the barometric pressures recorded at the deep wells can abruptly jump induced by the passage of squall line; instantly, the strong pulse-like disturbances were observed on groundwater level graphs associated with pressure jumps; ② The duration of disturbance could last as long as about 127 minutes for this case; ③ In the highfrequency band, the barometric waves induced by squall line have a period between 15 cpd (cycles per day) and 25 cpd. Correspondingly, the cross-correlation coefficients between barometric waves and groundwater changes can be lower than −0.95 for the four deep wells in this special frequency band. Furthermore, the barometric pressure response coefficients vary from about −4.9 mm/hPa to −6.9 mm/hPa for the four wells, determined as the linear regression coefficient between groundwater level and barometric pressure in the 15−25 cpd band-passed data. Our analysis shows that this work can extend our understating of the signatures caused by squall line in the field of groundwater research. Additionally, owing to the large amplitude of barometric waves, the squall line can help quantify the precise responses of groundwater levels in deep wells to barometric pressures in the high frequency band.

     

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