HR: 0830h
AN: OS41A-05    [Abstracts]
TI: Hydrography of the Entrance to the Gulf of California in November 2004
AU: * Castro, R
EM: rubenc@uabc.mx
AF: Facultad de Ciencias Marinas, Universidad Autonoma de Baja California Apartado postal 453, Ensenada, C.P., BC 22800 Mexico
AU: Collins, C
EM: brickspop@yahoo.com
AF: Department of Oceanography, Naval Postgraduate School 833 Dyer Road, Rm 328, Monterey, CA 93943 United States
AU: Mascarenhas, A
EM: asm38@yahoo.com
AF: Instituto de Investigaciones Oceanologicas, Universidad Autonoma de Baja California Apartado postal 453, Ensenada, C.P., BC 22800 Mexico
AU: Navarro, L F
EM: lufena@uabc.ens
AF: Facultad de Ciencias Marinas, Universidad Autonoma de Baja California Apartado postal 453, Ensenada, C.P., BC 22800 Mexico
AB: In November 2004, two high resolution hydrographic sections were occupied at the entrance to the Gulf of California. One section combined velocity data collected with a 300 kHz broadband ADCP with water properties obtained by a CTD which continuously profiled the upper 125 m. The second section combined velocity data collected with a 75 kHz ocean surveyor ADCP with traditional 1000 dbar CTD casts. As with previous sections, inflow was observed along Sinola but outflow occurred in the center third of the section. This meant that the isopycnal dome was located in the eastern half of section at 108.5W. Flow patterns and rates derived from ADCP measurements were in good agreement with those derived from geostrophy. Inflow and outflow extended from the surface to about 700 dbar. The maximum inflow (outflow) was about 35-40 cm/s (20 cm/s) between 100-200 (100-200) dbar and 108.2-108.4W (108.5-108.9W). Unlike previous sections, the portion of the section next to Baja California was marked by weak inflow. Waters in the upper layer were roughly divided into two classes by the isohaline S=34.7. To the east, Tropical Surface Waters (S greater than 34.3) lay between 50 and 90 dbar while to the west, Gulf waters (S less than 34.9) were observed. The Triaxus section showed the high resolution details (0.5 km horizontal and 0.5 dbar vertical) of the upper ocean structure. Highest productivity was observed at the base of the mixed layer in the western portion of the section where the warmest and highest salinity waters were found. Below the mixed layer, the fine structure of Subtropical Subsurface Waters formed in the Gulf is seen at depth along the 25.5 and 26.0 kg/m3 isopycnals. The separation between Tropical Surface and Gulf Waters was nearly vertical along 108.6W and marked by the zero isotach of cross stream flow as well as the zero isotach of inflow between 70 and 100 m.
DE: 4500 OCEANOGRAPHY: PHYSICAL
DE: 4516 Eastern boundary currents
DE: 4520 Eddies and mesoscale processes
DE: 4572 Upper ocean processes
SC: Ocean Sciences [OS]
MN: 2005 Joint Assembly