Open and coastal seas interactions south of Japan represented by an ensemble Kalman filter
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We investigated the feasibility of the ensemble Kalman filter (EnKF) to reproduce oceanic conditions south of Japan. We have adopted the local ensemble transformation Kalman filter algorithm based on 20 members’ ensemble simulations of the parallelized Princeton Ocean Model (the Stony Brook Parallel Ocean Model) with horizontal resolution of 1/36°. By assimilating satellite sea surface height anomaly, satellite sea surface temperature, and in situ temperature and salinity profiles, we reproduced the Kuroshio variation south of Japan for the period from 8 to 28 February 2010. EnKF successfully reproduced the Kuroshio path positions and the water mass property of the Kuroshio waters as observed. It also detected the variation of the steep thermohaline front in the Kii Channel due to the intrusion of the Kuroshio water based on the observation, suggesting efficiency of EnKF for detection of open and coastal seas interactions with highly complicated spatiotemporal variability.
KeywordsEnsemble Kalman filter Kuroshio Kii channel front OGCM
This work is part of the Japan Coastal Ocean Predictability Experiment (JCOPE) promoted by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). The code of the local ensemble transformation Kalman filter (LETKF) was obtained from http://code.google.com/p/miyoshi/, which is maintained by Dr. Takamasa Miyoshi. Sea surface height anomaly data of Jasons-1 and Jasons-2 and sea surface temperature of NOAA MCSST were downloaded from the US-GODAE website: http://www.usgodae.org/. AMSR-E data were produced by remote sensing systems and sponsored by the NASA Earth Science MEaSUREs DISCOVER Project and the AMSR-E Science Team. Data are available at http://www.remss.com/. In situ temperature and salinity profiles were obtained from the Global Temperature-Salinity Profile Program (GTSPP) website: http://www.nodc.noaa.gov/GTSPP/. Comments from two anonymous reviewers were useful for improvements of the earlier version of the manuscript.
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