Physical Oceanography, Vol.
ANALYSIS OF OBSERVATIONS AND METHODS FOR CALCULATING
HYDROPHYSICAL FIELDS IN THE OCEAN
GENERATION OF UPWELLING NEAR THE PACIFIC COAST OF MEXICO
S. N. Bulgakov,
N. P. Bulgakov,
É. N. Mikhailova,
and N. B. Shapiro
In a series of numerical experiments, we simulate the process of generation of coastal upwelling
induced by the winds of various directions in the central part of the Pacific Coast of Mexico
. The numerical nonlinear multilevel model [see É. N. Mikhailova, I. M. Se-
menyuk, and N. B. Shapiro, “Modeling of the variability of hydrophysical fields in the Tropical
Atlantic,” Izv. Akad. Nauk SSSR, Fiz. Atmosf. Okean., 27, No.
10, 1139–1148 (1991)] is
adapted to the region of investigations with 9-km space resolution by specifying the conditions of
flow through the open lateral boundaries. The results of numerical experiments demonstrate that
the NW, N, NE, and E winds are especially favorable for the generation of intense upwelling.
From the viewpoint of physical oceanography, the central part of the Pacific Coast of Mexico (PCM) loc-
ated to the south of the Gulf of California is studied quite poorly up to now . According to the available data
of oceanographic observations [3, 4] and satellite data , the PCM is a region with strong seasonal variability
caused by the monsoon climate and the combined action of waters of the Gulf of California and Pacific Ocean.
Upwelling can be regarded as one of the most interesting hydrophysical phenomena observed near the PCM. As
a rule, it is observed in spring and summer when the temperature contrasts between the surface warm and cold
upwelling waters are especially well pronounced.
Clearly, the wind is one of the main driving forces generating coastal upwelling. According to the classical
theoretical works [6–9] studying the east part of the stratified ocean with vertical walls and flat bottom, the north
wind parallel to the coast forms a flow and the Ekman flow drive off generating, in turn, the phenomenon of
The aim of the present work is to determine the types of winds most favorable for the generation of coastal
upwelling in the region of PCM with regard for the specific features of the complicated coastline and bottom
topography. For this purpose, we perform numerical calculations according to the three-dimensional numerical
model proposed in . As an object of investigations, we choose the region bounded between
1). This quasitriangular region with open lateral boundaries in the west and south is bounded
by the coastline in the NW–SE direction with a protruding zone of the Cabo Corrientes. The region is character-
ized by significant inhomogeneities of the bottom topography including a vast shelf zone (with depths less than
a group of islands (Tres Marias), a steep continental slope, and an abyssal domain with depths down to
Institute of Astronomy and Meteorology, University of Guadalajara, Guadalajara, Mexico.
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol..
Translated from Morskoi Gidrofizicheskii Zhurnal, No.
32–41, January–February, 2005. Original article submitted April 10,
0928-5105/05/1501–0027 © 2005 Springer Science+Business Media, Inc. 27