HIDROLOGIA DEL ALTO GOLFO DE CALIFORNIA II. CONDICIONES DURANTE INVIERNO, PRIMAVERA Y VERANO.

Eight cruises were carried on during winter, spring and c,ummer of 1973, in the northern end of the Gulf of California. Determinations ot temperabre, salinity, dissolved oxygen concentration, pH and meteorological conditions were mude. This is the continuation of the study presented by Alvarez Borrego and Galindo Bect (1974) on the fall conditions; completing the annual cycle. A great variability exists at the head of the Gulf, with minimum temperature of 8.2PC registered in December, and maximum of 3258°C in August; with minimum surface salinity of 35.28”/00, registred in October, and maximum of 41.00°/oo in July. There is no significant input of fresh water from rhe Colorado river to the Gulf during all year. This is demonstrated by ?he high salinities registered at what used to be the river mouth; with exception of the very few days when local rain is relatively ,high. The surface temperature gradienr reverses at the beginning of spring and fall, due to the annual cycle of solar radiation and atmosph,eric temperature. Salinity maintains in general the same gradient, wlth values increasing northwestwards.