Font Size: a A A

Study On The Heat Budget In The North Pacific

Posted on:2012-01-01Degree:MasterType:Thesis
Country:ChinaCandidate:S LiuFull Text:PDF
GTID:2120330335958696Subject:Physical oceanography
Abstract/Summary:PDF Full Text Request
Based on the simple ocean data assimilation(SODA)1958-2007 monthly mean datasets and the thermal equation, the characteristics of interannual and interdecadal variability of the North Pacific sea surface temperature anomalies(SSTA)and their local factors are analyzed. The variability of the North Pacific sea subsurface temperature(SUBT)and the factors impacting on SUBT are also studied. The differences between these factors beneath the mixed layer and at the surface are researched. The quantitatively studies of the heat budget in the North Pacific interior region are given, focusing on the heat transport and the mechanisms involved in, based on the heat budget equation.The mainly results are as following.After Aleutian low deepened and moved to the southeast of its previous positon, the North Pacific SST cooled in two regions. One is in the interior subtropical ocean around 30°N, controlled by the wind stress anomalies, another is near the confluence between the subpolar and the subtropical gyres around 40°N, controlled by the displacement of the zero wind stress curl line. Around the interior region, the SST anomaly reached its extreme during 1978-1982, and it was enhanced by the surface heat flux anomaly together with the meridional advection anomaly, which accounted for about 50-60% of the SST anomalies, while the residual term in the thermal equation accounted for about 20-50%. Around the confluence, the cooling began from 1975 both in the eastern part and in the western part. Both the heat flux and the meridional advection were responsible for the cooling around this region, especially during 1983-1988, the meridonal advection contributed more significantly than the heat flux. In the terms related to the advection, the meridional component has the strongest variability, two times larger than the zonal component, while the vertical advection is the smallest.The big-value of decadal variations of SUBT in the North Pacific is at the Kuroshio extension, which is strengthened from east to west. SUBT change in western Pacific lags 2a behind that in the central part. The meridional advection term at the subsurface also has obvious decadal feature, and at 400-600m the center of its decadal variations is where the maximum of SUBT anomaly is.The net meridional heat transportation in the North Pacific is almost concentrated in the upper 500m, especially upper 200m in winter. Its direction, value, and vertical structure are associated with the subtropical and subpolar gyres. The meridional heat transport has both obvious decadal variations and seasonal variations. The studies of the heat budget in the North Pacific interior region based on the integrated heat balance equation show that, for the decadal variability, the heat content change is mainly caused by meridional heat transport, with small contributions from the other terms. For the seasonal variability, the heat content change and the total net surface heat flux both have the period of one year, maybe there is tight relationship between them. Different physical processes control the heat budget in different regions.
Keywords/Search Tags:SST, surface heat flux, horizontal advection, subsurface, heat budget, meridional heat transport, North Pacific
PDF Full Text Request
Related items