A Seasonal Skill Comparison Between Operational Ocean Thermal Structure Products in the Northeast Atlantic/Norwegian Sea
Final journal article
NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS
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The U.S. Navys Fleet Numerical Oceanography Center has several operational products available for thermal structure nowcasts in the northeast AtlanticNorwegian Sea. These include regional nowcasts in the northeast AtlanticNorwegian Sea. These include regional nowcasts and short forecasts at 40 km resolution, global nowcasts and short forecasts at 1 90 km resolution, and two thermal climatologies at 50 km and 380 km resolutions. We propose two hypotheses 1 that the inclusion of real-time data in the nowcasts and forecasts improves nowcast skill over the use of climatology alone and 2 that increased real-time product resolution increases nowcast skill. This study addresses these hypotheses by comparing the six products listed above in the northeast AtlanticNorwegian Sea region on a seasonal basis. We extracted daily bathythermograph BT data from the real-time operational database in a 2,000 km diameter region centered on the Iceland-Faeroe Front from July 1989 through June 1990. We then compared each BT to the spatially-interpolated results from each of the six operational products. All comparisons were made prior to the BTs assimilation into the real-time products. For each season, we then accumulated three months of results to form a root-mean-square deviation of a given product relative to the verifying BTs. In this region, the results indicate that the real-time nowcasts perform better than both climatologies in autumn and winter. The results also demonstrate the advantage of increased resolution in fall and winter, but not as strongly. The spring and summer results do not produce definitive conclusions. Ocean models, Military oceanography, Data assimilation.
- Physical and Dynamic Oceanography