Auad, G., A. J. Miller and W. B. White, 1998:
Simulation of heat storages and associated heat budgets in the Pacific Ocean
1. El Nino Southern Oscillation timescale
Journal of Geophysical Research,
103, 27,603-27,620.
Abstract.
We use a primitive equation isopycnal model of the Pacific Ocean to simulate and diagnose the anomalous heat balance
on El Nino-Southern Oscillation, ENSO, timescales associated with heat storage changes observed in the expendable
bathytermograph (XBT) data set. We focus on the analysis of the total (diabatic plus adiabatic) and diabetic anomalous
heat balances in six areas of the tropical and subtropical North Pacific Ocean in the upper 400 m, The diabetic (i.e.,
from the model conservation temperature equation) and adiabatic (i.e., from the model mass conservation equation)
anomalous heat balances add up to the total anomalous heat balance. We computed the adiabatic/diabatic ratios to infer
the relative importance of both contributions in different areas and found that they are smaller than 2.0 in only two
regions (western equatorial and central North Pacific). The larger ratios (>2) were found along the corridor where
adiabatic anomalies propagate westward in the form of Rossby waves and at the eastern equatorial Pacific, For those
areas where the adiabatic/diabatic ratio is higher than about 2 the total anomalous heat balance is dominantly between
the temporal change of heat and the three-dimensional divergence of the heat flux. At the central North Pacific area
the total anomalous heat balance is between the temporal changes in anomalous heat, the surface heat flux and the
vertical advection of heat. Different ENSO events are not always controlled by the same physical processes in the
different areas, In many cases these differences are associated with the relative importance of adiabatic to diabatic
processes. For instance, the western equatorial Pacific is controlled in general by diabatic processes, while the eastern
equatorial Pacific is dominated by adiabatic physics most of the time.
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