The San Francisco call., 1898-08-01
Unga Island Was It's
 Starting Point.
JAPAN CURRENT GOT CHILLED
HAMMON'S STRIKING DISCOV-
 FRY AS TO THE REASON.
May Hereafter Be Able to Predict a Dry Summer in the Preced-
 ing Spring.

Forecast Official Hammon Is seriously working out a way of casting the horo- scope of California's climate months ahead so as to be able to warn the peo- pie of the valleys and mountains when another drought Is coming. The new idea is that in years when the great Japan current, which sweeps across the North Pacific Ocean just south of the Aleutian Islands, and then down the Pacific coast swings farther to the north and closer to those islands, 1t becomes colder there and later colder here, and the effect of this chilling of the water off the Califor- mia coast is to lessen the precipitation.
 This being the case, all that is neces- sary is to keep the Japan current located up there in the north. When 1t Is caught swinging north, to cool off, as it appa- rently does, for some unknown reason now and then, 1t may be known that the water will be unusually cold off the Cali fornia coast when the chilled current gets here. That trip takes about three months, so that if it is known here late in the summer and in the fall and in the winter what the Japan current is doing, it can be predicted in general way that there will or will not be the usual pre- cipitation here three or four months later. If it should be found that when the current goes north in the fall it stays there all winter, that would give us a pointer about our spring rains six months off
 MT. Hammon has developed some strik-- ing facts pointing to the correctness , ,a ;Ua oa his theory He began with a comparatl,ve study of the mass of water from the north within region of 300 miles off the California coast He observes:
 The amount of rainfall appears to be some what proportional to the number or degrees that the sea temperature is higher than the land. This observed by studying the rec ords of water temperatures taken py vessels off this coast as reported to the hydrographic office. It was also observed by Professor George Davidson some years ago. 1T py any means We were able to distinguish those years, when the sea temperatures would be abnor- mally cold, we might conclude that these would be dry seasons for California
 record of temperature on Unga Island, one of the AIeutian group, has been maintained during the past four years, showing that dur, ing the past year the winter months averaged 5 degrees higher temperature than usual. Un- fortunately there are other records known to exist from those islands of previous dry years in California, except an old Russian record from Unalaska Island This covers the that the year 1923 was abnornally warm, the normal No California rainfall records are in existence for that period but in Bancroft's erain yieIds at t6a Missions along the coast from San Rafael to San Diego. These show general failure of these crops at all missions in 1929, the total yield being but Se. GOO bush els while the average annual yield for the de- cade of 1S21-30. inclusive, was S7 25O bushels. This marked failure in crops in 1929 Is strong
 
 1S2S-29.
 MT. Hammon worked out chart fndf- eating by 8 curved line the departures from the normal temperature at Unga Island during the past four years, and similar chart showing the departures from the normal precipitation here. When these curves were opposed to each other. with the proper three months difference that is, September at Ungaa opposed to December here-the correspondence was remarkable During the rainy season or all these years, when the temperature curve Of Unga Island goes up the curve of precipitation here goes down, and the farther $one goes up the farther the other goes down. Says MT. Hammon:.s
 Satisfactory seasonal forecasts. are not ;rn- known At present othe5 Indian Meteorological Bureau are foretelHng quite accurately In gen eral terms the character of the coming sea son The Very abnormal conditions that have prevailed, during the past year over an ex- terYsIve area must be associated with very no- ticeable changes elsewhere. Should further sin- Iyestfgatior prove that these conditions were due 10 changes in the Japan current, notice able thousands of miles. from this shore, the value of the discovery would be inestimable
 MT. Hanirnon's review of the drought itself is accompanied by several carefully compiled tables, and Is the first general and comprehensive statement concerning +he drought that has appeared. The rain fall for the different sections of the State for theo season was as follows: