Quantifying How Observations Inform a Numerical Reanalysis of Hawaii
Abstract
When assimilating observations into a model via state‐estimation, it is possible to quantify how each observation changes the modeled estimate of a chosen oceanic metric. Using an existing 2 year reanalysis of Hawaii that includes more than 31 million observations from satellites, ships, SeaGliders, and autonomous floats, I assess which observations most improve the estimates of the transport and eddy kinetic energy. When the SeaGliders were in the water, they comprised less than 2.5% of the data, but accounted for 23% of the transport adjustment. Because the model physics constrains advanced state‐estimation, the prescribed covariances are propagated in time to identify observation‐model covariance. I find that observations that constrain the isopycnal tilt across the transport section provide the greatest impact in the analysis. In the case of eddy kinetic energy, observations that constrain the surface‐driven upper ocean have more impact. This information can help to identify optimal sampling strategies to improve both state‐estimates and forecasts.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 01, 2017
- Source ID
- 10.1002/2017jc012854
Entities
People
- Brian Powell
Organizations
- Office of Naval Research
- University of Hawaiʻi System