Continuing the MODIS Dark Target Aerosol Time Series with VIIRS For reflected sunlight observed from space at visible and nearinfrared wavelengths, particles suspended in Earthxe2x80x99s atmosphere provide contrast with vegetation or dark water at the surface. This is the physical motivation for the Dark Target (DT) aerosol retrieval algorithm developed for the Moderate Resolution Imaging Spectrometer (MODIS). To extend the data record of aerosol optical depth (AOD) beyond the expected 20year lifespan of the MODIS sensors, DT must be adapted for other sensors. A version of the DT AOD retrieval for the Visible Infrared Imaging Radiometer Suite (VIIRS) on the SuomiNational PolarOrbiting Partnership (SNPP) is now mature enough to be released as a standard data product, and includes some upgraded features from the MODIS version. Differences between MODIS Aqua and VIIRS SNPP lead to some inevitable disagreement between their respective AOD measurements, but the offset between the VIIRS SNPP and MODIS Aqua records is smaller than the offset between those of MODIS Aqua and MODIS Terra. The VIIRS SNPP retrieval shows good agreement with groundbased measurements. For most purposes, DT for VIIRS SNPP is consistent enough and in close enough agreement with MODIS to continue the record of satellite AOD. The reasons for the offset from MODIS Aqua, and its spatial and temporal variability, are investigated in this study.

Coastal Turbidity Derived From PROBAV Global Vegetation Satellite PROBAV (Project for OnBoard AutonomyVegetation) is a global vegetation monitoring satellite. The spectral quality of the data and the coverage of PROBAV over coastal waters provide opportunities to expand its use to other applications. This study tests PROBAV data for the retrieval of turbidity in the North Sea region. In the first step, clouds were masked and an atmospheric correction, using an adapted version of iCOR, was performed. The resulted water leaving radiance reflectance was validated against AERONETOC stations, yielding a coefficient of determination of 0.884 in the RED band. Next, turbidity values were retrieved using the RED band. The PROBAV retrieved turbidity data was compared with turbidity data from CEFAS Smartbuoys and adhoc measurement campaigns. This resulted in a coefficient of determination of 0.69. Finally, a time series of 1.5 year of PROBAV derived turbidity data was plotted over MODIS data to check consistencies in both datasets. Seasonal dynamics were noted with high turbidity in autumn and winter and low values in spring and summer. For low values, PROBAV and MODIS yielded similar results, but while MODIS seems to saturate around 50 FNU, PROBAV can reach values up till almost 80 FNU.