C2 s.3 



PAPERS PRESENTED. 



NOTES ON CLIMATE. 



BY DR. L. N. DIMMTCK. 



The southern half of Southern California lies within the 

 belt or zone denominated the "Calms of Cancer." This is a 

 region of calms, light airs, and variable winds. The barom- 

 eter stands higher in this belt than it does either to the north 

 or south. Over it the opposing trade winds meet and produce 

 a calm, and an accumulation of the atmosphere. Off the coast 

 to the west and southwest this belt widens out and culminates 

 in a permanent area of high atmospheric pressure, or a vast 

 anti-cyclone, the diameter of which is a-bout a thousand miles. 

 The barometer in this area stands at 30.20 inches. This piling 

 up of the atmosphere by the opposing forces, causes the great 

 pressure by its increased weight, and produces a downward 

 motion of the cold dry air from the upper regions. As the 

 pressure under this bank of calms is so much greater than it 

 is on. either side of it, the air is forced to flow out at the sea 

 level. From this ''immense stationery anti-cyclone" there 

 issues a broad belt of westerly winds. These winds before 

 reaching the west coast of California, pass over the cold cur- 

 rent of water, that coming from Alaska, flows southeastwardly 

 along the shores of California, as far south as point Concep- 

 tion, whence it passes to the south into deep water, no longer 

 following the coast. The temperature of the ocean air is 

 lovered by this passage, its capacity for retaining moisture is 

 greatly lessened, and the condensed moisture is in a large 

 part returned to the sea, and in part converted into fogs. 

 This explains why, notwithstanding the sea fogs that occur 

 upon the coast, the percentage of humidity and also the abso- 

 lute humidity contained in the atmosphere is so small. 



