Development of an in situ self calibrating ocean bottom pressure meter (OBP)

现场自校准海底压力计（OBP）的开发

• 批准号: 249894855
• 负责人: Dr. Hans-Hermann Gennerich
• 金额: --
• 依托单位: Fachgebiet Meerestechnik - Sensorik (aufgelöst)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/249894855?language=en
• 关键词: Development; situ; self; calibrating; ocean

Monitoring hydrostatic pressure at the seafloor plays a key role in several marine disciplines like marine geodesy, marine hydrocarbon reservoir monitoring, oceanography and the validation of satellite gravity products. But since its initial days more than 40 years ago down until today the high resolution sensors unchangedly suffer from a lack of long-term stability of the sensor calibration, preventing the unequivocal detection of long-term trends in all these disciplines.Our goal is to develop, test and build an in situ self-calibrating ocean bottom pressure meter, which is able to monitor and unequivocally recognize long-term pressure variations at the seafloor due to its built-in drift-quantification with a precision of better than 10 Pa i.e. 1 mm water column equivalent through the length of survey (one or multiple years) and therefore to resolve the expected trends - a task, which no instrument is able to cope with presently. Our method is to measure the difference between the environmental pressure and a frozen-in reference pressure. The reference pressure is captured in a chamber by closing the valve to the environment after the instrument was deployed at the seafloor. The innovative aspect of this concept for long-term monitoring is the combined usage of a differential pressure sensor with a temperature compensated reference pressure chamber, a strategy combining the advantages of significantly less drift and simple in situ calibration.Three orders less instrumental drift will be achieved, as the dynamic range of relative pressures is three orders less compared to absolute seafloor pressures (tidal height instead of full ocean depth) thus allowing smaller full scale of the sensor (drift amplitude scales with the full scale of the sensor). Quantification of the drift will be gained shorting both ports of the differential pressure sensor at the beginning and at the end of the survey, as the physical pressure difference then is zero. The challenge is to reduce temperature-caused noise in the reference pressure by intelligent choice of materials, geometry and temperature monitoring and to avoid rigorously even minimal potential leaks in the reference system.Our strategy has four crucial advantages over the only known competing approach, the in situ calibration of an absolute pressure sensor by means of a deadweight tester: Less sensor drift, more robustness and minor cost with the resulting option to install the instruments in geo-sensor networks.We plan to design, test and investigate a very basic system, to evaluate strengths and weaknesses as well as the options for an improvement (proof of concept). In a second step with a second proposal we want to implement the new insights and experiences from this prototype to build an instrument which has the potential to become the new standard for long-term in situ pressure observations in the deep sea.

监测海底静水压力在海洋大地测量、海洋油气藏监测、海洋学和卫星重力产品验证等若干海洋学科中发挥着关键作用。但是，从40多年前的最初几天到今天，高分辨率传感器一直受到传感器校准缺乏长期稳定性的影响，无法明确检测所有这些学科的长期趋势。我们的目标是开发、测试和建造一种现场自校准海底压力计，由于其内置的漂移量化，能够监测并明确识别海底的长期压力变化，其精度优于10 Pa，即在整个勘测过程中相当于1 mm水柱（一年或多年），因此解决预期的趋势-这是一项目前没有任何文书能够科普的任务。我们的方法是测量环境压力和冻结参考压力之间的差异。在将仪器部署在海底后，通过关闭阀门来获取腔室中的参考压力。这一长期监测概念的创新之处在于将差压传感器与温度补偿参考压力室结合使用，这一策略结合了显著降低漂移和简单原位校准的优点。将实现三阶更小的仪器漂移，因为相对压力的动态范围比绝对海底压力小三个数量级（潮汐高度而不是整个海洋深度），从而允许传感器的更小的满刻度（漂移幅度与传感器的满刻度成比例）。在测量开始和结束时，将通过短接压差传感器的两个端口来获得漂移的量化，因为物理压差为零。我们的挑战是通过明智地选择材料、几何结构和温度监控来降低参考压力中由温度引起的噪声，并严格避免参考系统中甚至是最小的潜在泄漏。与唯一已知的竞争方法相比，我们的策略具有四个关键优势，即通过自重测试仪对绝对压力传感器进行现场校准：更少的传感器漂移，更强大的鲁棒性和较小的成本，从而选择在地理传感器网络中安装仪器。我们计划设计，测试和调查一个非常基本的系统，以评估优点和缺点以及改进的选项（概念验证）。在第二个步骤中，我们提出了第二个建议，希望利用这一原型的新见解和经验，建立一个有可能成为深海长期原位压力观测新标准的仪器。