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Sept. 2007

SORCE Receives 4-Year Extension to Study the New Solar Cycle

LASPI'm sure you have heard of the old cliché wondering if a tree falls in the forest and nobody is present to observe it, does it really occur? With the interesting, but controversial, predictions of the next solar cycle maximum perhaps being higher or lower than the past cycle maximum, there is much interest in how the next cycle might evolve. But how will we know what the results are if we are not observing the solar irradiance during the next maximum that is expected to occur in 2012? This might have been the case, but fortunately NASA has recently extended the Solar Radiation and Climate Experiment (SORCE) for another four years past its planned termination date of January 2008.
The SORCE mission provides direct measurements of the total solar irradiance (brightness) and also spectral measurements of the solar irradiance, both being critical to observe how the solar variations might evolve during the next cycle maximum. The SORCE extension, along with the possible extension of the NASA TIMED mission with its solar ultraviolet irradiance measurements, will provide for the first time, the total solar radiative output (total irradiance) and the spectral distribution of this radiation from X-rays to the infrared (spectral irradiance) during solar maximum conditions.
The SORCE mission has been extended for 4 more years until January 2012. The majority of the work is at CU-LASP for the daily operation of the satellite and instruments using a combination of professionals and students and for the data analysis and distribution of solar irradiance results to the public. The SORCE mission is operated as a PI-mode mission at CU-LASP with Dr. Tom Woods as the PI (original PI is Dr. Gary Rottman, who retired in 2005) and is supported by NASA GSFC.

June 2007

The Sun Approaches Its 11 Year Minimum and Activity Cycle 24

Observations reveal that magnetic activity on the Sun varies dramatically over time, with a near periodic 11-year cycle. Large dark sunspots are frequently observed on the Sun during solar maximum and few, if any, sunspots are seen during solar minimum. Figure 1 compares images of the Sun’s visible disk during high (left) and low (right) solar activity. Sunspot occurrence is an indicator of a change in the Sun’s energy output. In addition to the sunspots, large bright prominences called faculae­—faculae is a Latin word that means small torches—are more commonly observed during solar maximum. The occurrence of sunspots and faculae changes the total energy output from the Sun—total solar irradiance. (Read more...)


Figure 1: Near the peak of the solar activity cycle many sunspots appear regularly on the Sun, as seen in the left image on 30 March 2001 in Cycle 23. Currently, solar activity is near the minimum of the 11-year cycle and sunspots may be absent entirely, as seen on 8 May 2007, in the right image.

March 2007

Enhanced SORCE Data Products

The SORCE Science Data System (SDS) performs all science data production activities. It consists of the hardware and software components necessary to generate, manage, and distribute all SORCE standard science data products. The SORCE SDS routinely produces total solar irradiance and solar spectral irradiance data products on a daily basis. The Science Data System utilizes raw spacecraft and instrument telemetry, routinely-maintained calibration data, and other ancillary information to produce and distribute a variety of data products that have been corrected for all known instrumental and operational effects. (Read more)