The North-Western part of the Black Sea is highly affected by eutrophication due to nutrient and sediment load inflow from the Danube River, which is the second largest delta in Europe. To get a general spatial picture of the water quality of the Romanian coast, it is not only time consuming, but also hard to measure with traditional in situ sampling. To solve these issues, methods have been developed to use close range spectral measurements for accurate and cheap assessments in real-time for the concentrations of Chlorophyll-a, Total Suspended Matter and water transparency. This paper presents the applicability of a state-of-the-art hand-held hyper-spectral sensor and a simple water transparency indicator for monitoring water quality. The fieldwork was conducted during the summer of 2013 on the Romanian coast of the Black Sea. The same techniques are used to calculate these parameters from satellite images (MODIS). The validation results and potential applications of the instruments will be discussed.
Optical close-range instruments can be applied to derive water quality parameters for monitoring purposes and for validation of optical satellite data. In situ radiometers are often difficult to deploy, especially from a small boat or a remote location. The water insight spectrometer (WISP-3) is a new hand-held radiometer for monitoring water quality, which automatically performs measurements with three radiometers (L sky , L u , E d ) and does not need to be connected with cables and electrical power during measurements. The instrument is described and its performance is assessed by an intercomparison to well-known radiometers, under real fieldwork conditions using a small boat and with sometimes windy and cloudy weather. Root mean squared percentage errors relative to those of the TriOS system were generally between 20% and 30% for remote sensing reflection, which was comparable to those of the other instruments included in this study. From this assessment, it can be stated that for the tested conditions, the WISP-3 can be used to obtain reflection spectra with accuracies in the same range as well-known instruments. When tuned with suitable regional algorithms, it can be used for quick scans for water quality monitoring of Chl, SPM, and aCDOM.