The remote sensing group of the GeoForschungsZentrum Potsdam (GFZ) is the principal investigator of the hyperspectral and multiangle CHRIS PROBA data. The objective for the Compact High Resolution Imaging Spectrometer (CHRIS) on the platform PROBA is to provide Earth surface reflectance data in the visible/near infrared, at high spatial and spectral resolution, for atmospheric, land and water studies. The instrument will use the PROBA pointing capabilities to obtain reflectance measurements with a wide range of different viewing configurations (CHRIS-PROBA). Therefore BRDF studies can be done on the multi-angle effect on the in water light distribution as well as on the different grades of the specular reflection at the air-water interface and additionally on different land surface types.

Existing hyperspectral GFZ algorithms for lake water quality analysis are adapted to the CHRIS data. Simultaneously to the CHRIS PROBA acquisition on 10th October 2002, a shipborne field expedition for ground truth data took place on the Lake Mueritz (Germany). In situ data conclude a set of in-water and above-water field spectrometer (GER1500) measurements together with water sampling activities. The water samples are analysed on pigment concentration (chlorophyll and pheopigments) and DOC by the partner of Institute for applied Freshwater Ecology (IaGB). Aditionally, SPM concentration and absorption by cDOM are measured at the GFZ. For adapting remote sensing algorithms to shallow water conditions we measured secchi depth and did a survey of the submerse macrophytes distribution and lake sediment type.