Table 1.—Comparative temperatures—U.S. Naval 
Undersea Oceanographic Tower for airborne infrared 
sea surface temperature surveys, 1963-68/1972-74. 
1972-74 1963-68 
monthly mean monthly mean 
temperature temperature 
Month Xe) °F °C ay 
April 14.6 58.2 14.4 58.0 
May 16.8 62.3 15.6 60.0 
June 18.4 65.3 16.7 62.0 
July 19.7 67.4 18.9 66.0 
August 20.0 68.0 20.0 68.0 
September 17.3 63.3 18.3 65.0 
October 17.3 63.3 18.3 65.0 
upwelling area was also observed when a temperature 
decline, sometimes sharp, was frequently present west of 
Mission Beach and the NUC tower when proceeding 
toward the coast. The kelp bed area west of Point Loma 
appears to be slightly warmer than the area to the north 
off Mission Beach. Near the area south of Point Loma 
and about the San Diego harbor entrance channel, a sig- 
nificant drop in temperature is usually observed, this 
resulting from upwelling near the south end of the Point. 
Temperatures tend to remain lower than those found 
west of the Point Loma peninsula and they remain lower 
to the southeast of Point Loma, off the Coronado Strand, 
and increase slightly off Imperial Beach. Immediately 
south of the International Border of Mexico is frequently 
found the northern edge of an extensive coastal upwell- 
ing zone. The effects of this upwelling increase to the 
south and extend further offshore. Warmer tempera- 
tures than those found near the coast of Mexico are en- 
countered offshore about the Coronado Islands, and tem- 
peratures in this area are more typical of those found off- 
shore in the northern portion of the survey area. 
ACKNOWLEDGMENTS. 
The interest and cooperation of E. C. LeFond, Dale 
Good, Paul Hansen, and the staff associated with the 
NUC oceanographic tower in making sea surface calibra- 
tion observations is appreciated. To a number of person- 
nel from the Southwest Fisheries Center, NMFS, NOAA, 
and to Clyde Melendy of the National Weather Service, 
NOAA, who took time from their activities to assist in 
the airborne surveys, I express my appreciation. 
LITERATURE CITED 
MILLER, F. R., and R. M. LAURS. 
1975. The El Nino of 1972-1973 in the eastern tropical Pacific 
Ocean. Inter-Am. Trop. Tuna Comm. Bull. 5(16):403-448. 
SQUIRE, J. L., Jr. 
1971. Measurements of sea surface temperature on the eastern 
Pacific continental shelf using airborne infrared radiometry, Aug- 
ust 1963-July 1968. U.S. Coast Guard Oceanogr. Rep. 47 (CG373- 
47), 229 p. 
