Important volcanic material injections in the troposphere can induce significant environmental and meteorological perturbations. Several volcanic eruptions have been recently observed before the eruption of Eyjafjallajökull in Iceland, but this one was an important source of problems to European air transport, as this volcano was directly injecting material over northern Europe. It has thus become of major importance to precisely characterize transported material (identify silicate and sulfate aerosol and their properties) from observations and provide such information as inputs and control to transport models. IR observations have long been used to characterize volcanic emitted material. It is one of the advantages of the CALIPSO mission to combine IR and lidar instruments to provide co-located observations directly exploitable to improve the characterization of aerosol and clouds. CALIPSO, as part of the A-Train, further benefits from an unprecedented observational environment, which enables combined analyses with CloudSat and AQUA. Furthermore, the overpasses of the A-Train provide a snapshot into observations from geostationary platforms, such as MSG over Europe and Africa, which can be of valuable interest to follow the dispersion and modifications of plumes on a regular basis. In this presentation, we will focus on observations made after the eruption of the Chaiten volcano in Chile in 2008, and of the Icelandic volcano in 2010. Emitted plumes were transported over areas possibly covered with low clouds, so that potential observations from the surface need to be complemented, and that radiometric observations in the visible are largely perturbed. We show that the complementary observations of A-Train and geostationary sensors allow to better identify and characterize volcanic ash properties, and to follow the evolution of the plumes. More specifically, we focus on IR observations to characterize the size of silicate particles, and on combined CALIPSO IIR and lidar observations, involving newly developed research products, to analyze aerosol optical depths over clouds and ocean.