Observing system simulation experiments on the Oahu Regional Ocean Model

Abstract

Observing system simulation experiments were conducted using the Oahu Regional Ocean Modeling System. A twin experiment was implemented in which synthetic observing systems were withheld to establish the impact of each observing system on 4-day ocean forecasts over a 6 month experiment period. Synthetic High Frequency(HF) Radar had significant impacts on the forecasts across the region. It provided a surface velocity constraint that influenced forecasts at depth and in areas of the region not directly surveyed by HF Radar. Additional analyses of the observing systems were conducted at the outflow plume depth of a potential pilot Ocean Thermal Energy Conversion (OTEC) site off the south coast of Oahu as well as the circulation of Mamala Bay. Synthetic satellite data had a positive impact on the temperature forecasts, especially in the island wake area, west of Oahu. Glider data from continuous synthetic runs between Makapu'u and Penguin Banks and data from a synthetic mooring stationed in the deepest part of the Ka'iwi Channel constrained the model well in the Ka'iwi Channel. They both showed positive impact on temperature and velocity forecasts near the Ka'iwi Channel.