CORRELATED SIGNALS & CAUSAL TRANSPORT OF SEA SURFACE TEMPERATURE ANOMALIES IN THE NORTH ATLANTIC

Correlation;causation;sea surface temperature;transport;response;fluctuation;dissipation;advection;diffusion;Earth & Planetary Sciences

Jeffress, Stephen AlexanderHaine, Thomas ;

Johns Hopkins University

关键词: Correlation;    causation;    sea surface temperature;    transport;    response;    fluctuation;    dissipation;    advection;    diffusion;    Earth & Planetary Sciences;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/37136/JEFFRESS-DISSERTATION-2014.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

A sea surface temperature (SST) anomaly is a relatively warm or cold patch of water on the ocean surface. This thesis develops and applies a method for quantifying the transport of these anomalies in the midlatitude North Atlantic. Previous studies have estimated the advective transport from the time-lagged correlation of SST anomalies. We show that this approach does not consider diffusive SST transport or relaxation to atmospheric temperatures. The total transport is better quantified by the response function (Green;;s function) that solves the SST continuity equation for an impulsive external forcing. The impulse response framework clarifies the relationship between correlation and causation in the context of SST transport. The response function for North Atlantic satellite observed SST is estimated using a fluctuation-dissipation based inverse method. The method also provides a best fit linear operator that is decomposed into estimates of the SST velocity, diffusivity, and decay rate fields. The large scale features of the estimates compare favorably with previous studies. As far as we know, this thesis provides the first empirically derived estimate of an SST impulse response function. An unexplained result of our work is that mechanisms besides ocean currents appear responsible for the slow speed of SST anomaly propagation.