272
D. H. CUSHINQ
ception. The high pressure system intensifies in spring and summer
and moves northward (Reid et al., 1958), so the upwelling shifts northward in season. The California Current streams south and is about 350
miles wide and 330 m deep (California, Department of Fish and Game,
1953). Three permanent summer eddies become established : (a) off
Cape Mendocino in northern California, (b) south-east of Point Conception, about 100 miles WNW of Los Angeles, from which is constituted the south California Countercurrent, and (c) south of Punta
San Eugenio, in Baja California. They are probably generated by upwelling, the southerly eastern boundary current and the local bottom
structures. During the period of upwelling, a deep countercurrent
( >200 m) runs from Baja California to a point north of Cape Mendocino and perhaps along the shelf off Oregon (Smith, 1969). When the
north-westerly winds weaken, there is a countercurrent inshore, called
the Davidson Current (Reid et al., 1958), which has been recognized off
the coast of Oregon (Smith, 1969). Lynn (1967) says that the countercurrent in late autumn, winter and early spring runs from central
California to British Columbia; a proper upwelling system has been
described by Stefansson and Richards (1964) off the coast of Washington State in summer and early autumn. Their work also shows that the
effect of upwelling on the coast of Oregon may be masked sometimes
by the Columbia River plume. So there is a countercurrent in deep
water over the shelf in summer and inshore at the surface in the winter.
The California Current starts to leave the shelf off central California and
its precursor, the West Wind drift, reaches the shelf north of Cape
Flattery.
Upwelling occurs south of Cape Mendocino, Point Conception and
Punta San Eugenio (Reid et al., 1958). A very rough relation was shown
between wind stress parallel to the coast and the upwelling as estimated
by the low temperatures inshore (California Department of Fish and
Game, 1952). A detailed analysis of the seasonal distribution was made
in the years 1949-52 (California Department of Fish and Game, 1953)
at thirteen positions between Cape Blanco in northern California and
Punta San Juanica in southern Baja California, by months. In 1949,
upwelling occurred in MarchlApril and September along the whole
coast ; in 1951 it was restricted to the first half of the year with a slight
seasonal shift to the north. In 1951, the upwelling was less intense, with
a light spring season and some in OctoberiDecember between Point
Conception and the northern part of Baja California. This winter upwelling was probably connected with the intense and widespread upwelling in the following spring, in 1952. These data illustrate the
variability of upwclling in time and space and the scasonnl shift north-
D. H. CUSHINQ
ception. The high pressure system intensifies in spring and summer
and moves northward (Reid et al., 1958), so the upwelling shifts northward in season. The California Current streams south and is about 350
miles wide and 330 m deep (California, Department of Fish and Game,
1953). Three permanent summer eddies become established : (a) off
Cape Mendocino in northern California, (b) south-east of Point Conception, about 100 miles WNW of Los Angeles, from which is constituted the south California Countercurrent, and (c) south of Punta
San Eugenio, in Baja California. They are probably generated by upwelling, the southerly eastern boundary current and the local bottom
structures. During the period of upwelling, a deep countercurrent
( >200 m) runs from Baja California to a point north of Cape Mendocino and perhaps along the shelf off Oregon (Smith, 1969). When the
north-westerly winds weaken, there is a countercurrent inshore, called
the Davidson Current (Reid et al., 1958), which has been recognized off
the coast of Oregon (Smith, 1969). Lynn (1967) says that the countercurrent in late autumn, winter and early spring runs from central
California to British Columbia; a proper upwelling system has been
described by Stefansson and Richards (1964) off the coast of Washington State in summer and early autumn. Their work also shows that the
effect of upwelling on the coast of Oregon may be masked sometimes
by the Columbia River plume. So there is a countercurrent in deep
water over the shelf in summer and inshore at the surface in the winter.
The California Current starts to leave the shelf off central California and
its precursor, the West Wind drift, reaches the shelf north of Cape
Flattery.
Upwelling occurs south of Cape Mendocino, Point Conception and
Punta San Eugenio (Reid et al., 1958). A very rough relation was shown
between wind stress parallel to the coast and the upwelling as estimated
by the low temperatures inshore (California Department of Fish and
Game, 1952). A detailed analysis of the seasonal distribution was made
in the years 1949-52 (California Department of Fish and Game, 1953)
at thirteen positions between Cape Blanco in northern California and
Punta San Juanica in southern Baja California, by months. In 1949,
upwelling occurred in MarchlApril and September along the whole
coast ; in 1951 it was restricted to the first half of the year with a slight
seasonal shift to the north. In 1951, the upwelling was less intense, with
a light spring season and some in OctoberiDecember between Point
Conception and the northern part of Baja California. This winter upwelling was probably connected with the intense and widespread upwelling in the following spring, in 1952. These data illustrate the
variability of upwclling in time and space and the scasonnl shift north-