G. Auad et al., SIMULATION OF HEAT STORAGES AND ASSOCIATED HEAT BUDGETS IN THE PACIFIC-OCEAN 1 - EL-NINO SOUTHERN-OSCILLATION TIMESCALE, J GEO RES-O, 103(C12), 1998, pp. 27603-27620
We use a primitive equation isopycnal model of the Pacific Ocean to si
mulate and diagnose the anomalous heat balance on El Nino-Southern Osc
illation, ENSO, timescales associated with heat storage changes observ
ed in the expendable bathytermograph (XBT) data set. We focus on the a
nalysis of the total (diabatic plus adiabatic) and diabetic anomalous
heat balances in six areas of the tropical and subtropical North Pacif
ic Ocean in the upper 400 m, The diabetic (i.e., from the model conser
vation temperature equation) and adiabatic (i.e., from the model mass
conservation equation) anomalous heat balances add up to the total ano
malous heat balance. We computed the adiabatic/diabatic ratios to infe
r the relative importance of both contributions in different areas and
found that they are smaller than 2.0 in only two regions (western equ
atorial 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 t
otal 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 cont
rolled 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 eas
tern equatorial Pacific is dominated by adiabatic physics most of the
time.