LOS ANGELES, March 28 (Xinhua) -- The average temperature in California increased
two degrees Fahrenheit between the year 1950 and 2000 largely due to human
activities, according to a new study released Wednesday by the journal
Climate Research.
The average temperature in urban areas increased more than in rural regions,
with the largest temperature increases registered in Southern California
and the San Francisco Bay area, and the slowest increase in the Central
Valley, according to the study conducted by researchers at the California
State University in Lo sAngeles and the National Aeronautics and Space
Administration (NASA).
The researchers came to the conclusion by analyzing data from 330 weather
stations in seven of the state's major climatic sub-regions.
In the Los Angeles Civic Center, the average nighttime temperature has
increased by nine degrees since 1878. During the same period, the average
daytime temperature increased 3.6 degrees.
"California nights are heating up, giving us a jump-start on hotter days," NASA
researcher Bill Patzert said. "This is primarily due to increased urbanization,
not increases in cloudiness or precipitation. Rainfall and snowfall
didn't increase significantly for most California stations during the
study period."
The temperature of the Pacific Ocean may also be tied to the temperature
increases. The ocean temperature increased 0.16 degrees per decade from 1950 to
2000.
"Climate-change models and assessments often assume global warming's
influence here would be uniform. That is not the case," California State
University researcher Steve LaDochy said.
"If we assume global warming affects all regions of the state, then the
small increases our study found in rural stations can be an estimate of this
general warming over land. Large increases would therefore be due to local or
regional changes in land surface use due to human activities."
The only area in the state to cool between 1950 and 2000 was a narrow
band of the state's northeast interior.
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