the detection of clouds and aerosols with the backscattersonde MAS during the m55 geophysica campaign for envisat validation

Multiwavelenght Laser Backscattersondes (MAS) have been widely used from a variety of airborne platforms for in situ measurements of optical properties of clouds and atmospheric particulate as well as their phase and composition [Adriani et al. 1999]. MAS is an aerosol backscattersond able to measure backscatter ratio (BR) and depolarization (D) ratio of the airmass in close proximity to its platform, with 2 seconds of temporal resolution. In the cases reported afterward, given the aircraft cruising speed, that translate into 400 metres of horizontal resolution. BR is a sort of optical mixing ratio of the particles in the atmosphere while D gives information about asphericity of the scatterers, hence their thermo dynamical state. In the last year we have deployed this instrument in the ENVISAT validation campaigns. A description of the instruments, a survey of results obtained so far and indications for future use will be given.