The white light from sun is having VIBGYOR colours. Among this Violet is having lower wave length. However only blue is scattered more in sky and land than others. Why is it so ?
You have to multiply the color-dependent intensity function of the sunlight (red in http://de.wikipedia.org/wiki/Rayleigh-Streuung#mediaviewer/File:Rayleigh-Streuung_von_Sonnenlicht.png). With the Rayleigh scattering function ~f^4, the product is the blue graph in that picture. The maximum shifts from about 500 nm to 280 nm. For checking, you need a detector with sufficient sensibility in the UV region. Since your eyes spectrum is limited to about 400 nm, the maximum seems to shift back to about 400 nm.