August 11, 2008
Those who view the Sun, and not CO2, as a driver of temperatures on Earth look to various measures of solar activity for explanations of climate change. For one such measure — radio waves from the Sun, or solar flux — they look to Canada’s Dominion Radio Astrophysical Observatory in the Okanagan valley, near Penticton, British Columbia. What they find supports the view that another Little Ice Age could be coming.
Solar activity of late has been extraordinarily low. You can follow the solar flux along with the scientists, if you wish, by periodically clicking here. The column that’s third from the right shows the actual observed readings. The columns to its right are corrected by several percent to remove various distortions. The column at the extreme right hand is considered the most accurate of the three.
The observatory’s Solar Radio Monitoring Program, operated in conjunction with the Canadian Space Agency, produces three precise measurements of the solar flux density each day — solar radio emissions at 10.7 cm wavelength. The observatory believes that the 10.7 cm solar radio flux may be the most heavily used single piece of astronomical information in the world.
Why 10.7 cm? In 1946, famed Canadian astronomer Arthur Covington decided to measure the Sun’s “radio flux” — the variations in the Sun’s energy output at radio wavelengths. After realizing that the flux changed daily, and wondering if these variations were related to the sunspots on the Sun’s surface, he took advantage of a partial solar eclipse to monitor variations as the Moon covered the sunspots. In discovering that the sunspots emit much stronger radiation than the more luminous unspotted areas, he established that sunspots are associated with radiation “hot spots.” Covington used a radio wavelength of 10.7 cm (2800 megaHertz) to monitor the activity of the Sun.
For an explanation of the science, I offer the following excerpt from the National Geophysical Data Center in the U.S., which relies on the observatory’s data:
“The sun emits radio energy with a slowly varying intensity. This radio flux, which originates from atmospheric layers high in the sun’s chromosphere and low in its corona, changes gradually from day-to-day, in response to the number of spot groups on the disk. Radio intensity levels consist of emission from three sources: from the undisturbed solar surface, from developing active regions, and from short-lived enhancements above the daily level. Solar flux density at 2800 megaHertz has been recorded routinely by radio telescopes near Ottawa (February 14, 1947-May 31, 1991) and Penticton, British Columbia, since the first of June, 1991. Each day, levels are determined at local noon (1700 GMT at Ottawa and 2000 GMT at Penticton) and then corrected to within a few percent for factors such as antenna gain, atmospheric absorption, bursts in progress, and background sky temperature.”
Lawrence Solomon is executive director of Energy Probe and author of The Deniers: The world-renowned scientists who stood up against global warming hysteria, political persecution, and fraud.