ABNORMAL SUMMERS IN THE PERUVIAN COASTAL CURRENT 807 



the same time serves to underline the difficulty to understand the move- 

 ments which bring these high temperatures to the zone between Ilo 

 and Arica. 



Figure 12 differs from the other charts in so far as it combines the 

 observations of only two ships which sailed the whole Peruvian and 

 part of the Chilean coast from Talara to Iquique during 20 days (16th 

 of February to 8th of March 1948). The map contains also some earlier 

 observations made by the northbound vessel off Cabo Blanco and in 

 the interior of the Gulf of Guayaquil (8/9 of February) in order to 

 represent a typical distribution of high sea temperatures in the zone of 

 Cabo Blanco and northeast of it. Both these ships passed, according 

 to a previous understanding, a zone situated 80-90 miles W of Pisco 

 in order to obtain information about the conditions there at this time 

 of the year. The comparison between the observations registered W 

 of the northern part of the Peruvian shore (4°-6°S) and those made 

 while sailing from Talara to Callao, suggests that a very strong inva- 

 sion of warm water must have taken place in the 8 days between 9th 

 and 1 7th of February which shoved the 24° isotherm more or less 90 

 miles to the SE. The most interesting feature of Figure 12 is the appear- 

 ance of the temperature of 26.2°C off Arica (27th of February) whilst 

 neither the first boat passing the zone W of Pisco (16th of February) 

 nor the second one (7th of March) observed more than 25.3 °C. Between 

 these dates the warm water off Pisco had expanded, but it cannot be 

 said if its extension found on the 7th of March was already diminished 

 after having reached a culmination in the foregone days or if the ex- 

 pansion was a steady one during all the time. The high temperatures 

 off Arica place before us the following problem: If they are connected 

 and how far with the invasion of warm water in 6°-7°S, or the other 

 one in 13°-14°S. That the temperature registered off Arica was a 

 recent one, can be concluded from the fact that data obtained in the 

 same half-degree-squares before and after the sailing from Iquique prove 

 that the water was cooler between the 22nd and 24th than between the 

 26th and 27th of February. 



It seems undeniable that such a "tongue" of warm water as showrt 

 in Figure 12 and which is also confirmed by a series of maps in a recent 

 paper by Bini (1952) must have its origin in the region situated between 

 Ilo and Arica. It seems difficult, however, to trace back the warm 

 water and connect it with waters still warmer in further northern parts 

 of the Ocean. It seems possible to draw the isotherms for 25 °C in 17° 

 and 18° S (Figs. 4, 7 and 12) in such a manner that they join the iso- 

 therms for the same temperatures at the N or NW of Callao. The 

 author does not feel that svich a course might be considered correct. 



