Solar measurements

Column-averaged infrared solar measurement between 1983 and 2003 at Kit Peak Observatory (2090 m a.s.L, Colorado, United States) resulted in an averaged tropospheric volume mixing ratio of 1814 48 ppb with trend equal to 8.3 2.2 ppb yr i in 1983 decreasing to 1.9 3.7 ppb yr" in 2003 (Rinsland et al. 2006). A similar trend has been observed in the lower stratosphere where at the 120-10 hPa ( 16-30 km altitude) at 25°N-35°N from 2004-2008 a value of 1370 ppb was estimated using spectroscopic measurement (Rinsland et al. 2009). In 1985, this value was estimated to be 1151 ppb. 

The solar spectrum may be divided into three regions for discussion the UV (280-400 nm), the visible (VIS, 400 760 nm), and the IR (760-2500 nm). There is no scientific consensus on the boundaries of these regions nor is there even agreement on whether they need to be defined for solar measurement purposes. 

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