30% . The surface wind stress was computed and the wind stress vec- 

 tor was resolved into north-south (meridional or alongcoast) and east- 

 west (zonal or crosscoast) components. Ekman transport was 

 computed and offshore-onshore transport was determined by resolv- 

 ing the vector component perpendicular to the general trend of the 

 coasdine. Sverdrup transport was calculated as described by Nelson 

 (1977). 



The surface temperature and salinity data were obtained from sam- 

 ples taken daily at Hopkins Marine Station of Stanford University 

 during the period January 1963 to May 1975. SST data from June 

 1975 to December 1978 were taken at the Monterey tide station by 

 NPS personnel. Salinity data from Hopkins Marine Station are not 

 available later than May 1975. 



To examine the relationship between sea level and dynamic height, 

 a series of hydrographic cast data were assembled for a station 

 located in mid-Monterey Bay, about 19 km northwest of the tide sta- 

 tion (Fig. 1). This hydrographic station is located near the mouth of 

 the Monterey submarine canyon where the water depth is over 900 

 m. The hydrographic cast data were taken semimonthly by the 

 Hopkins Marine Station during 1963-73. Sampling during the first 

 years of the program was limited to the upper 50 m of the water 

 column but in 1968 the sampling depth was increased to over 500 m. 

 Sampling was discontinued by Hopkins in December 1973 and was 

 resumed by Moss Landing Marine Laboratory from July 1974 to 

 June 1978. 4 



The Hopkins and Moss Landing hydrographic data were key- 

 punched and profiles of temperature and salinity and temperature- 

 salinity curves were plotted for each station. Using these plots, 

 obvious errors in the data were eliminated. 



The time series of hydrographic stations had a gap in early 1974 

 between the end of Hopkins sampling and the beginning of Moss 

 Landing sampling. Several expendable bathythermograph (XBT) 

 drops taken during this period by NPS are available for the mid-bay 

 location. To be able to utilize these XBT data, it was necessary to 

 estimate a salinity value for each temperature value. A density 

 value was calculated for each pair of temperature-salinity observa- 

 tions in the hydrographic cast data and correlation anal) sis was 

 made. Density was found to be better correlated with temperature (r 

 = 0.98) than was salinity with temperature (r = 0.96). Thus a den- 

 sity value was computed for each temperature in the XBT profiles 

 and then a companion salinity value was calculated for each tem- 

 perature and density pair. This procedure also allowed estimation of 

 salinity for some of the hydrographic casts where temperature but 

 not salinity values were recorded. The hydrographic data were then 

 checked for density instabilities and finally, dynamic height was 

 calculated for each profile for the 0/200. 6/400. and 200 400 db 



'Hopkins Marine Station. CalCOFI Hydrographic Data, collected on approxi- 

 mately bi-weekly cruises on Monterey Bay. California. Annual reports for years 

 1968 to 1973 tmineogr.). Hopkins Marine Station. Pacific Grove. CA 93950. 



■■Broenkow. W. W . S R. Lasley. and G. C. Schrader. 1975. CalCOFI 

 Hydrogiphic Data Report. Monterey Bay. July to December 1974. Tech. Publ. 75- 

 1 Moss Landing Mar Lab . Moss Landing. CA 95039. 



Broenkow. W. W.. S. R. Lasley. and G. C. Schrader. 1976. CalCOFI Hydro- 

 graphic Data Report. Monterey Bay. January to December 1975. Tech. Publ. 76-1. 

 Moss Landing Mar. Lab.. Moss Landing. CA 95039. 



Lasley. S. R. 1976. CalCOFI Hydrographic Data Report. Monterey Bay. January 

 to December 1976. Tech. Publ. 77-1. Moss Landing Mar. Lab.. Moss Landing. CA 

 95039. 



Chinburg. S. J., and S. R. Lasley. 1977. CalCOFI Hydrographic Data Report. 

 Monterey Bay. January to December 1977. Tech. Publ. 78-1. Moss Landing Mar. 

 Lab., Moss Landing. CA 95039. 



Chinburg. S. J. 1979. CalCOFI Hydrographic Data Report. Monterey Bay. Janu- 

 ary to June 1978. Tech. Publ. 79-1. Moss Landing Mar. Lab . Moss Landing. CA 

 95039 



(decabars) levels. The depth of maximum calculation was limited 

 by the XBT profiles which extended to only 460 m. The final time 

 series contained 202 profiles to at least 400 m in the 10-yr period 

 April 1968 to June 1978. 



Monthly means and anomalies of sea level, and of the ocean and 

 atmospheric data described in the above sections, are presented 

 graphically and in tabular form in Appendix B. 



SEA LEVEL AT MONTEREY 



Although the time series of hourly sea levels contains much valu- 

 able information on the occurrence, amplitude, and duration of 

 anomalous short period sea level fluctuations, it was decided for this 

 study to concentrate on variations of sea level of monthly period and 

 longer and on their atmospheric and oceanographic causes. Weekly 

 and 6-h sea level data are discussed but in a more limited way as are 

 the statistical characteristics of hourly deviations from the predicted 

 sea level. Readers interested in short period fluctuations are referred 

 to Maixner ( 1 973) who examined Monterey sea level data during the 

 year 1971. 



Means and Variations 



Hourly Sea Level.— To analyze nontidal sea level variations, 

 which are small compared with the normal tide range in this area, the 

 tidal signal must first be removed. Three methods for this are averag- 

 ing, filtering, or subtracting predicted tides from the observed. The 

 Tide Predictions Branch of the NOS performed a harmonic analysis 

 of 365 d of hourly Monterey tide height values and isolated 37 har- 

 monic constituents (Maixner 1973). Using the 20 constituents whose 

 amplitudes were >0.61 cm, the NOS computed predicted hourly 

 tide heights for the period of record, 1963 through 1976. Predicted 

 hourly heights were then subtracted from the 13 yr of observed 

 hourly heights to yield nonastronomic residuals. The frequency of 

 occurrence of these sea level differences (observed minus predicted), 

 which total nearly 108.000 values, approximates a normal or Gauss- 

 ian distribution (Fig. 3). Of the observations, 94.5% lie within 15.2 

 cm (0.5 ft) of the predicted tide and 99.9% lie within 30.5 cm (1.0 

 ft). The maximum observed difference was 39.6 cm. The standard 

 deviation of the differences was 8.7 cm, skewness -0.02, and kurto- 

 sis 3.2. 



15 -r 



-45 -15 15 



Observed Minus Predicted Tide Height (cm) 



Figure 3 — Frequency of occurrence of differences between observed and pre- 

 dicted hourly tide heights at Monterey, Calif.. 1963-76. 



The distribution of hourly differences describes nontidal sea level 

 variations over a 13-yr period but gives no information about sea- 

 sonal variations of the frequency distribution. Are distributions for 

 winter months the same as those for summer? To define the seasonal 



