Laboratory Measurements of Drift Rates in Pressure Gauges Proposed for Seafloor Geodesy

建议用于海底大地测量的压力表漂移率的实验室测量

• 批准号: 1536424
• 负责人: Glenn Sasagawa
• 金额: $ 20.6万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536424&HistoricalAwards=false
• 关键词: Laboratory; Measurements; Drift; Rates; Pressure

Pressure gauges installed on the seafloor are key instruments for monitoring tides, offshore earthquakes and tsunamis, seafloor volcanoes, and offshore oil and gas fields. While valuable, the instruments slowly drift, which make long-term measurements more difficult or even impossible to use. This research will simulate seafloor pressure and temperature conditions in the laboratory, and periodically re-calibrate the instruments to determine the drift behavior. New sensors and methods to correct the drift in place will also be tested. The results will improve the characterization and application of pressure measurements for such important problems.Pressure observations for seafloor geodesy provide important data on many seafloor deformation processes, including volcanism and tectonic deformation. Pressure observations are also relevant to rates of sea level rise and other oceanographic signals. Existing pressure sensors all drift in
time (dominated by linear and exponentially decaying functions of time), which limits their use in the aforementioned applications to relatively short period signals (days to months). Methods such as seafloor pressure campaign surveys and in-situ
calibration can effectively remove the drift, but these methods are costly and thus limited
in usage. The manufacturers of pressure gauges have proposed new sensors and methods to address the drift issue, which are significantly simpler and would be much less costly to implement. One approach uses a secondary sensor to measure only sensor drift due to residual water vapor contamination (hypothesized to be a dominant term), independent of the applied pressure.
 Another method hypothesizes that the drift rate can be measured by comparison to a one-atmosphere low drift sensor. This research will subject an array of existing and new sensors to simulated seafloor pressures and temperatures over extended periods of time (4-6 months at a minimum). The sensors will be periodically calibrated with a primary, drift free metrological standard known as a deadweight tester. Drift determinations with the new sensors and methods will be made, and compared to the estimates determined by primary standard. This experiment will determine the efficacy and uncertainties of these new methods. If these new approaches are validated, this will enable the development of new seafloor instruments, and the ocean sciences will have access to new methods that will benefit observations of important phenomena. In turn, better understanding of seafloor tectonics and volcanism will improve the assessment and response to potential geological hazards.

安装在海底的压力计是监测潮汐、近海地震和海啸、海底火山和近海油气田的关键仪器。虽然有价值，但仪器会慢慢漂移，这使得长期测量变得更加困难，甚至不可能使用。这项研究将在实验室模拟海底压力和温度条件，并定期重新校准仪器，以确定漂移行为。用于纠正漂移的新传感器和方法也将进行测试。这些结果将改进压力测量在这些重要问题上的表征和应用。海底大地测量的压力观测为包括火山作用和构造变形在内的许多海底变形过程提供了重要数据。压力观测也与海平面上升速度和其他海洋信号有关。现有的压力传感器都在时间上漂移(由时间的线性和指数衰减函数主导)，这将它们在前述应用中的使用限制在相对较短的周期信号(天到月)。海底压力运动测量和现场校准等方法可以有效地消除漂移，但这些方法成本高昂，因此在使用中受到限制。压力表制造商已经提出了新的传感器和方法来解决漂移问题，它们明显更简单，实施成本也会低得多。一种方法使用二次传感器，只测量由于残留水蒸气污染(假设是主导项)引起的传感器漂移，而与施加的压力无关。另一种方法假设漂移率可以通过与单大气低漂移传感器进行比较来测量。这项研究将使一系列现有的和新的传感器在较长的时间内(至少4-6个月)受到模拟的海底压力和温度的影响。传感器将使用一种主要的、无漂移的计量标准进行定期校准，该标准称为自重测试仪。将使用新的传感器和方法进行漂移测定，并与主标准确定的估计值进行比较。这项实验将决定这些新方法的有效性和不确定性。如果这些新方法得到验证，这将使开发新的海底仪器成为可能，海洋科学也将获得有利于观测重要现象的新方法。反过来，更好地了解海底构造和火山活动将改善对潜在地质灾害的评估和反应。