A flare sensitive 3 h solar flux radio index for space weather applications

作者：Acebal Ariel O^*; Sojka Jan J

来源：Space Weather-The International Journal of Research and Applications, 2011, 9: S07004.

DOI：10.1029/2010SW000585

Many space physics models use the F10.7 as their input for solar activity. The F10.7 is a daily index derived from solar radio measurements taken at 2800 MHz, excluding activity from solar flares. In this paper, we compute a 3 h composite index, similar, in part, to the F10.7, using solar radio observations taken at 2695 MHz (11.1 cm) by the United States Air Force's Radio Solar Telescope Network. This index, called the F11.1 index, is similar to the F10.7. But unlike the F10.7 index, which is measured three times each day, at 1700, 2000, and 23 UT, F11.1 consists of eight measurements each day, uniformly distributed over 24 h. These 3 h intervals are aligned in UT with the planetary geomagnetic index Kp's time intervals. Each interval provides an F11.1 value that minimizes solar flare radio emission data. This composite index also provides two additional pieces of quantitative information that the F10.7 does not provide. The first is a factor, ranging from 0 to 1, indicating how representative the single F11.1 value is of this entire 3 h period (representation accuracy parameter). The second is a measure of how much of the 3 h interval can be classified as solar disturbed or as having a flare in progress (duration parameter). These aspects together have relevance for ionospheric modeling/specification for solar conditions in which significant change can occur over a 24 h period.

• 出版日期2011-7-21