Collaborative Research: Measuring abyssal warming with seismic Scholte waves

由于其巨大的热容量，海洋吸收了人为温室气体捕获的大部分多余能量，从而调节了全球变暖的速度。海洋变暖的精确测量对于理解地球的能量不平衡和气候异常至关重要。本项目将采用重复海底自然地震激发的地震肖特波监测全球大尺度深海海洋变暖的新方法。初步结果证明了该方法的可行性，并将推广到全球海洋。现有的地震数据可用于追溯上世纪90年代的深海海洋变暖。这些结果将补充水文测量，并提高对深海对地表强迫响应动力学的理解。这项工作将为过去几十年深海变暖提供新的观测约束。调查人员将系统地搜索自20世纪80年代以来重复发生地震的浅层海底。由这些重复事件激发的肖特波沿着海底传播，它们的传播速度对深海温度很敏感。因此，在重复事件之间的朔尔特波传播时变化限制了深海温度的变化。Scholte波传播时间对深海温度的敏感性将通过波传播的数值模拟来计算。灵敏度核将用于解释测量到的传播时间变化，推断沿波浪路径的平均深海变暖，并量化不确定性。推断的变暖将与水文和Argo数据进行比较。提供盆地尺度深海海洋变暖的直接估计。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Due to its large heat capacity, the ocean absorbs most of the excess energy trapped by anthropogenic greenhouse gases and thus regulates the rate of global warming. Accurate measurements of the ocean's warming are critical for understanding Earth's energy imbalance and climate anomalies. This project will employ a novel method of using seismic Scholte waves excited by repeating natural submarine earthquakes to monitor the global large-scale abyssal ocean warming. Preliminary results demonstrate the feasibility of the method, which will be expanded to the global ocean. Existing seismic data can be used to track abyssal oceawn warming back to the 1990s. The results will complement hydrographic measurements and improve understanding of the dynamics of the response of the abyssal ocean to surface forcing.This work will provide new observational constraints on abyssal ocean warming over the past few decades. The investigators will systematically search for shallow submarine repeating earthquakes since the 1980s. Scholte waves excited by these repeating events travel along the seafloor, and their propagation speed is sensitive to abyssal temperatures. Scholte wave travel time changes between repeating events thus constrain abyssal temperature change. The sensitivity of Scholte wave travel times to abyssal temperatures will be calculated using numerical simulations of wave propagation. Sensitivity kernels will be used to interpret the measured travel time changes, to infer average abyssal ocean warming along the waves' path, and to quantify uncertainties. The inferred warming will be compared against hydrographic and Argo data where available. Providing direct estimates of basin-scale abyssal ocean warming.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.