HR: 18:00h
AN: U24A-06    [Abstracts]
TI: Circulation and Hydrography in the Southern Gulf of California prior to the NAM onset (cruise NAME-1, June 2004)
AU: * Lavin, M F
EM: mlavin@cicese.mx
AF: Dpto. de oceanografia Fisica, CICESE, CICESE, Departamento de Oceanografía Física, km 107 Carr. Tijuana/Ensenada, Ensenada, BC 22800,
AU: Castro, R
EM: rubenc@uabc.mx
AF: UABC, Facultad de Ciencias Marinas, UABC-FCM, Apartado Postal No. 453, Ensenada, BC 22860, Mexico
AU: Beier, E
EM: ebeier@cicese.mx
AF: CICESE, La Paz, CICESE, La Paz, Miraflores 334 Bella Vista, La Paz, BCS 23050, Mexico
AU: Amador Buenrostro, A
EM: amador@cicese.mx
AF: UABC, Facultad de Ciencias Marinas, UABC-FCM, Apartado Postal No. 453, Ensenada, BC 22860, Mexico
AB: The thermohaline structure and circulation in the entrance to the Gulf of California during June 2004 is described based on very detailed data (CTD, LADCP and surface drifters) collected in a 17-day survey, supported by coetaneous satellite data (winds from QuikScat and daily 1-km AVHRR). The AVHRR images show extensive mesoscale structures in the region (fronts, eddies, streamers, etc.), the most striking being: (a) a cool streamer extending from the California Current domain up to one fourth of the Gulf, (b) a warm intrusion along the mainland shelf, and (c) a narrow warm streamer attached to the tip of the Baja California peninsula. The ship data show that the latter was associated to a narrow outgoing current which carried Gulf of California Water; its core (0.2-0.4 m/s) was at 200 m, and reached down to 500 m depth. By contrast, there was a very strong current flowing into the Gulf on the eastern warm side of the thermal front created by the presence of the cool streamer, with speeds up to 0.60 m/s in the surface and 0.20 m/s at 200 m depth. There was also an ingoing coastal current on the mainland shelf, with weak surface currents but a well defined subsurface structure with speeds ~0.25 m/s at its core between 70-200 m. The two ingoing currents formed a very strong (speeds 0.40-0.80 ms-1) and narrow (~30 km) inflowing coastal current between the surface and 150 m depth that carried Tropical Surface Water in the upper 20 m, water from the Shallow Salinity Minimum, and Subtropical Subsurface Water below the 18 ºC isotherm. By resampling three cross-sections one week apart, it was possible to conclude that most of the observed changes in the temperature and salinity fields of the upper layers were dominated by advection, in agreement with previous indirect evidence from heat and salinity balances and limited observations.
DE: 3329 Mesoscale meteorology
DE: 4200 OCEANOGRAPHY: GENERAL
DE: 4243 Marginal and semi-enclosed seas
DE: 4500 OCEANOGRAPHY: PHYSICAL
DE: 4520 Eddies and mesoscale processes
SC: Union [U]
MN: 2007 Joint Assembly