Variability in Ocean Color Validation Measurements during the November 2014 NOAA VIIRS Cal/Val Cruise

To accurately monitor and to try to understand the Earth’s changing climate and ecosystems from ocean color remote sensing data, we must first be able to resolve environmental differences that are smaller than the changes in the system itself. Developing a climate data record requires the merging of multiple ocean color sensors which compounds the problem. We use calibration and validation to try to understand our ocean color measurement accuracy capability. The Marine Optical BuoY (MOBY) has provided a consistent standard of precision over time between ocean color missions. Assuming that the MOBY water-leaving radiance measurements are accurate, the ocean color sensors are then standardized to that reference and global measurements are conducted. The accuracy of the water-leaving radiance measurement that the satellite measures at different locations is not as clear. Multiple validation measurements at MOBY have been conducted using different instruments, however, environmental variability and differences between instruments can obscure the accuracy of the validation. Many validation investigations using various instrumentation have been conducted all over the world to constrain the accuracies of the ocean color sensor in different environments. Each validation measurement incurs unique uncertainties. To explore the variability in ocean color validation measurements, ten near-simultaneous measurements of remote sensing reflectance were measured in a variety of water types by VIIRS Cal/Val team members using profiling, floating and above-water instrumentation. This was conducted November 10 to 22, 2014 during a dedicated VIIRS Cal/Val cruise off the East Coast of the United States aboard the NOAA Ship Nancy Foster. Variability in the measurements are analyzed to try to better understand uncertainties in ocean color validation measurements.