Advances in combining optical citizen observations on water quality with satellite observations as part of an environmental monitoring system. - Timo Pyhälahti; Timo Toivanen; Kari Y. Kallio; Marko Jarvinen; Matthieu Molinier; Sampsa S. Koponen; Ville Kotovirta; Chengyuan Peng; Saku Anttila; Marnix Laanen; Matti Lindholm (IGARSS, 2015)