A Thirty-Month Seafloor Test of the A-0-A Method for Calibrating Pressure Gauges
A Thirty-Month Seafloor Test of the A-0-A Method for Calibrating Pressure Gauges
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用于校准压力表的 A-0-A 方法的为期 30 个月的海底测试
DOI：
10.3389/feart.2020.600671
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发表时间：
2021
影响因子：
3
通讯作者：
J. Paros
中科院分区：
文献类型：
--
作者：
W. Wilcock;D. Manalang;E. Fredrickson;M. Harrington;G. Cram;J. Tilley;J. Burnett;Derek Martin;Taro Kobayashi;J. Paros
海洋大地测量对于了解板块构造、地震周期和火山过程非常重要。海底大地测量的一种方法是使用海底压力计在校正上覆海洋和大气的重量变化后感测海底海拔的垂直变化。使用压力表的一个挑战是传感器容易漂移。 A-0-A方法是一种校正漂移的新方法。阀门用于在短时间内定期将测量的压力从外部海洋切换到大气压下的仪器外壳内部。将内部压力读数与精确的气压计进行比较，以测量漂移，假设低压和高压下的漂移相同。我们描述了在蒙特利湾 MARS 有线天文台上 900 m 深度对 A-0-A 方法进行的为期 30 个月的测试，使用的仪器包括两个 A-0-A 校准压力计和一个三分量加速度计。校准之前，两个压力传感器分别漂移 6 和 2 hPa。校准后，校正后的压力传感器的偏移量相互一致，误差在 0.2 hPa 以内。漂移校正的确定外部压力测量结果显示，实验期间压力呈 0.5 hPa/年增加的趋势。根据加速度计测量的倾斜变化对仪器沉降的测量进行校正，但趋势可能包括不影响倾斜的沉降分量。然而，观测到的压力增加趋势与卫星测高计算结果以及附近位置的重复电导率、温度和深度预测非常吻合，并且压力增加与厄尔尼诺南方涛动的预期趋势一致。我们推断 A-0-A 漂移校正的准确度优于每年 105 分之一。需要进行额外的长期测试以及与海洋观测和其他漂移校正方法的比较，以了解 A-0-A 漂移校正的精度是否与两个压力传感器之间每年 106 的一致性中观测到的一部分相匹配。
Geodetic observations in the oceans are important for understanding plate tectonics, earthquake cycles and volcanic processes. One approach to seafloor geodesy is the use of seafloor pressure gauges to sense vertical changes in the elevation of the seafloor after correcting for variations in the weight of the overlying oceans and atmosphere. A challenge of using pressure gauges is the tendency for the sensors to drift. The A-0-A method is a new approach for correcting drift. A valve is used to periodically switch, for a short time, the measured pressure from the external ocean to the inside of the instrument housing at atmospheric pressure. The internal pressure reading is compared to an accurate barometer to measure the drift which is assumed to be the same at low and high pressures. We describe a 30-months test of the A-0-A method at 900 m depth on the MARS cabled observatory in Monterey Bay using an instrument that includes two A-0-A calibrated pressure gauges and a three-component accelerometer. Prior to the calibrations, the two pressure sensors drift by 6 and 2 hPa, respectively. After the calibrations, the offsets of the corrected pressure sensors are consistent with each other to within 0.2 hPa. The drift corrected detided external pressure measurements show a 0.5 hPa/yr trend of increasing pressures during the experiment. The measurements are corrected for instrument subsidence based on the changes in tilt measured by the accelerometer, but the trend may include a component of subsidence that did not affect tilt. However, the observed trend of increasing pressure, closely matches that calculated from satellite altimetry and repeat conductivity, temperature and depth casts at a nearby location, and increasing pressures are consistent with the trend expected for the El Niño Southern Oscillation. We infer that the A-0-A drift corrections are accurate to better than one part in 105 per year. Additional long-term tests and comparisons with oceanographic observations and other methods for drift correction will be required to understand if the accuracy the A-0-A drift corrections matches the observed one part in 106 per year consistency between the two pressure sensors.