Patel, M.R.; Zarnecki, J.C. and Catling, D.C.
Ultraviolet radiation on the surface of Mars and the Beagle 2 UV sensor.
Planetary and Space Science, 50(9)
In this paper a simple radiative transfer model for the transmission of UV to the surface of Mars is presented for the wavelength range 190–410 nm. The model accounts for the variable presence of dust aerosols in the martian atmosphere and its effects upon direct and diffuse irradiance. A range of situations is presented, including variations in orbital position, latitude, time of day, dust loading and ozone presence. High dust loading is seen to have an inverting effect on direct/diffuse transmission ratios, with a significant amount of illumination still being provided even at high optical depths typical of dust storms. Diffuse transmission is also observed as the primary component close to sunrise and sunset as expected. An ozone absorption feature is seen for high-latitude northern winter cases, offering limited shielding centred around 250 nm in the biologically damaging region of the UV spectrum.
The use of the model is then discussed in the role of designing and developing the Beagle 2 UV sensor, an instrument to measure the surface UV flux between 200 and 400 nm and set to land on the surface of Mars in 2003. The model is used to determine flux levels and spectral regions of particular interest, leading to a detailed instrument design and specification.
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