전구해양순환모델로 모의한 인도네시아 통과류의 경년변.

Abstract

Interannual variability of the Indonesian Throughflow (ITF) has been investigated using a global ocean circulation model based on the HYCOM (Hybrid Coordinate Ocean Model). The longitudinal grid spacing of the model is 1.5 degree and the latitudinal grid spacing is 1 degree to the south of 65 N with finer resolution up to 1/3 degree near the equatorial region. North of 65 N has variable resolution finer than 0.5 degree using the arctic bipolar patch grid. The model has 30 vertical layers with maximum depth of 4500 m. The intrinsic energy loan sea ice module of HYCOM is also applied. The atmospheric forcing is adopted from the monthly surface heat and momentum fluxes of ECMWF 40 year Reanalysis (ERA-40) data. For the surface flux correction, the sea surface salinity has been relaxed to the climatological data with a time scale of 30 days and the long wave correction algorithm has been applied to the surface thermal radiation flux. Before applying the ERA-40 forcing, the model had been spun up for 50 years using the COADS climatological forcing from the initial state derived from the Levitus; climatology.The standard deviation of modeled sea surface temperature (SST) during the 1958 ; 2001 is well simulated comparing with that of observational SST. The prominent ENSO variability is well reproduced in regard with the conventional Nino 3.4 index as well as related sea level variability. The depth integrated long term mean ITF transport at 113.5 E is about 16 Sv with the standard deviation of 2.7 Sv. Though the ITF transport shows a linear trend of -0.1 Sv/yr, which needs further discussion, the transport anomaly from this trend shows a good correlation with ENSO variability. Generally the larger/smaller ITF transport than the normal have been found during the La Nina/El Nino phase. Further study plan on the variabilities of the ITF and the Pacific western boundary currents and their role on the climate change will be discussed.