UPDATE: I personally visited this station today, thanks to a family visit that coincidentally took me to within a couple of miles of this station. It’s on a rooftop at the fire station. I’ll have a complete report tomorrow, but here are some preliminary photos I’m submitting via WiFi at a local Starbucks a short distance away. – Anthony
From the Orange County Register:
August 7th, 2008, 2:00 pm by grobbins
The average annual temperature in Santa Ana has increased by 7.5 degrees in less than a century, a spike largely attributed to urbanization which has seen the city’s population climb from less than 15,000 to more than 350,000. The temperature has gone from a low of 59.7 degrees in 1920 to 67.2 in 1997, with yearly temperatures near the all-time high as recently as 2006.
“Santa Ana now has a lot more buildings, parking lots and streets, which absorb and hold heat, some of it through the night,” says Ivory Small, science officer at the San Diego office of the National Weather Service.
The NWS analyzed the city’s climate and weather based on daily temperature readings from the Santa Ana Fire Station, which has been recording temperatures since 1916. The upward trend is depicted here by Register illustrator Scott Brown.
Forecasters calculated the average yearly temperature by determining the average high and average low temperature for each month. Then they divided those figures by two and got the average monthly temperature. Then they added up the average temperature for January through December of each year and divided by 12, getting the average annual temperature.
Santa Ana’s population has been on a steady, and basically predictable, rise for decades. The average annual temperature also has risen steadily. But the temperature increase didn’t occur in a predictable, incremental year-by-year pattern. There were lots of hiccups. For example, the average high for 1961 was 64.0 degrees. Three years earlier, the average high was 65 degrees.
Scientists say the average temperature didn’t smoothly rise year-by-year partly due to natural variability. In other words, some years are hotter than others because of natural fluctuations in weather and climate.
“The increase in temperatures in Santa Ana, as well as an increase in extreme heat days and in heat waves is primarily — about 60 percent — due to the ‘urban heat island effect,’ ” says Bill Patzert, a climatologist at the Jet Propulsion Laboratory in Pasadena.
“Santa Ana is embedded in the dramatic urbanization or ‘extreme makeover’ of Orange County. More homes, lawns, shopping centers, traffic, freeways and agriculture, all absorbing and retaining solar radiation, making Santa Ana and Orange County warmer.
“On a larger scale, Orange County is atmospherically connected to our ever-expanding and warming Southern California megalopolis. Global warming due to increasing greenhouse gases is responsible for about 40 percent of the overall heating observed in Southern California. “