(i) Introduction: Solar radiation and the composition of Earth's atmosphere. (ii) Theory of propagation of solar radiation: Basic concepts, black body, absorption-scattering-emission, radiation transfer equation. (iii) Radiative transfer in the atmosphere: Molecular absorption and scattering, Rayleigh and Mie scattering, optical properties of airborne particles and clouds, multiple scattering phenomena. (iv) Photochemistry in the atmosphere: Basic concepts, photochemistry of stratospheric and tropospheric ozone, photolysis rates of basic gases. (v) Theory of radiation measurements: Thermal devices, photoreceptors, spectrophotometers, calibration, spectral and angular response of instruments. (vi) Basic principles of meteorological measurements: temperature, humidity, wind, pressure, humidity, upper atmosphere measurements and vertical distribution of gases.