Rotational Raman scattering in the Earth's atmosphere ... - SRON

4 Chapter 1
Figure 1.1: Example of a solar irradiance spectrum (F in mW m −2 nm −1 ; black curve) and an Earth
radiance spectrum of a vegetated scene in the USA (I in mW m −2 nm −1 sr −1 ; grey curve) measured
by GOME on July 2, 1998. The lines of low intensity in the solar spectrum are Fraunhofer lines (see
Section 1.2). The names of prominent Fraunhofer lines are indicated in the figure.
Figure 1.2: The reflectivity spectrum is defined as r = πI/(µ 0 F), where I is the Earth radiance spectrum,
F is the solar irradiance spectrum, and µ 0 is the cosine of the solar zenith angle. The upper curve shows a
reflectivity spectrum of a cloudy scene over the Pacific Ocean (µ 0 =0.37). The lower curve is a reflectivity
spectrum of a clear-sky land scene (µ 0 =0.92) that was constructed from the two spectra in Fig. 1.1. The
O 2 A band near 760 nm and the strong absorption by O 3 (< 340 nm) are indicated. The inset zooms-in
on the clear-sky reflectivity spectrum in the range 350–400 nm to show the Ring effect structures.