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。准确测量海洋变暖对于了解地球的能量不平衡和气候异常至关重要。该项目将采用一种新的方法，利用重复的天然海底地震激发的Scholte地震波监测全球大规模深海海洋变暖。初步结果表明，该方法的可行性，这将是扩大到全球海洋。现有的地震数据可用于追踪1990年代以来的深海海洋变暖。这些结果将补充水文测量，增进对深海对表面强迫的动态反应的了解，并将为过去几十年深海变暖提供新的观测制约因素。调查人员将系统地寻找自20世纪80年代以来的浅海底重复地震。由这些重复事件激发的Scholte波沿着海底传播，其传播速度对深海温度很敏感。重复事件之间的Scholte波旅行时间的变化，从而约束深海温度的变化。将利用波传播的数值模拟计算Scholte波传播时间对深海温度的敏感性。敏感性核将用于解释测量的旅行时间变化，推断沿着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阿尔戈数据进行比较。提供盆地尺度深海海洋变暖的直接估计。该奖项反映了NSF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.