Sea Level Variations at Panama

Forty-eight-year records of sea level, and other variables, were analyzed for Balboa and Cristobál. It was found that from 1909 to 1962 the sea level has increased by 8.5±1.5 cm at Balboa and 7.1±2.0 cm at Cristobál. No significant trends were found in the climatological records. The increase in sea level at Panama, therefore, is probably due to subsidence of the land. The sea level oscillations at Balboa are similar to those occurring elsewhere along the northwest coast of South America. The rms amplitude of the annual sea level oscillation is 10.5 cm at Balboa and 3.8 cm at Cristobál. The corresponding values of the nonannual sea oscillations are 4.5 cm and 3.3 cm, respectively. The sea level difference, Balboa minus Cristobál, varies from about 8 cm in March to about 33 cm in June, In exceptional spring months the sea level may be higher by a few centimeters on the Caribbean side of the isthmus than on the Pacific side. A spectral analysis of the records in the frequency range between zero and 6 cycles per year showed significant peaks corresponding to the annual and semiannual cycles. An interesting peak suggesting a 4-year oscillation was found in the atmospheric pressure spectrums, but not elsewhere. At Balboa, there is a strong and direct relation between oscillations of sea level and sea surface temperature.