| dc.contributor.author | Carr, Mary-Elena. | en_US |
| dc.date.accessioned | 2014-10-21T12:35:47Z | |
| dc.date.available | 1991 | |
| dc.date.issued | 1991 | en_US |
| dc.identifier.other | AAINN71454 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55255 | |
| dc.description | Physical and biological processes are examined for the upper layer of the equatorial Pacific using data from a meridional transect along 150$\sp\circ$W, and from a five day time series made at 0$\sp\circ$. The data were acquired in spring of 1988. A free-fall vertical microstructure profiler, ELITESONDE, was used to estimate the rate of dissipation of turbulent kinetic energy. The goals of this study were to understand how the forcing due to air-sea flames and the fine-scale velocity and density structure influenced the meridional and temporal patterns of dissipation and to make a nitrate budget for the emphotic layer of the equatorial region. Hydrographic and meteorological data were typical for spring: the wind speed was low, the air temperature was higher than the water temperature and the equatorial undercurrent (EUC) was shallow and intense. | en_US |
| dc.description | The meridional transect revealed a maximum in the rate of dissipation of turbulent kinetic energy, $\epsilon$. This peak was statistically significant to 95% confidence intervals between 1$\sp\circ$S and 0$\sp\circ$ below 40 m. coinciding with the high vertical shear associated with the EUC. | en_US |
| dc.description | The time series observations at 0$\sp\circ$ revealed a weak diurnal cycle in dissipation, confined to the upper 20 m and without deep night-time maxima as observed in Tropic Heat 1. The low wind speeds and shallow EUC core during the measurement period are consistent with the absence of deep mixing events at night. Dissipation was maximum during the day at 55 m, possibly associated with tidal forcing. The diurnal variability of the water column was governed by internal forcing rather than air-sea fluxes as was the case in Tropic Heat 1. | en_US |
| dc.description | The zonal momentum budget was studied using the data from the equatorial time series. The wind stress at the surface was comparable to the climatological value of the integrated zonal pressure gradient between 0 and 60 m. The high dissipation values within the water column provided a large turbulent stress term at 55m. Consequently, the residual of the proposed momentum balance was only $-$19% of the zonal pressure gradient. | en_US |
| dc.description | The nitrate budget is estimated for the equatorial region. Vertical advection into the meridional box was estimated from the observed meridional currents. The turbulent flux of nitrate was estimated from the dissipation measurements and the nitrate profile assuming gradient transport. The net supply due to advection (vertical supply minus meridional loss) is three times the turbulent flux. The total supply is compared with two concurrent measurements of biological consumption to provide an approximate budget. The supply was larger than the measured incorporation of nitrate into particles but comparable to the rate of nitrate disappearance from incubated samples. The discrepancy between new production estimates from physical supply or nitrate disappearance and from nitrate incorporation into particles suggests that dissolved organic nitrogen (DON) may play an important role in the equatorial region. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1991. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Physical Oceanography. | en_US |
| dc.subject | Biology, Oceanography. | en_US |
| dc.title | Interactions between physical and biological processes in the equatorial Pacific. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
