Despite growing recognition of the importance of public data to the modern economy and to scientific progress, long-term investment in the repositories that manage and disseminate scientific data in easily accessible-ways remains elusive. Repositories are asked to demonstrate that there is a net value of their data and services to justify continued funding or attract new funding sources. Here, representatives from a number of environmental and Earth science repositories evaluate approaches for assessing the costs and benefits of publishing scientific data in their repositories, identifying various metrics that repositories typically use to report on the impact and value of their data products and services, plus additional metrics that would be useful but are not typically measured. We rated each metric by (a) the difficulty of implementation by our specific repositories and (b) its importance for value determination. As managers of environmental data repositories, we find that some of the most easily obtainable data-use metrics (such as data downloads and page views) may be less indicative of value than metrics that relate to discoverability and broader use. Other intangible but equally important metrics (e.g., laws or regulations impacted, lives saved, new proposals generated), will require considerable additional research to describe and develop, plus resources to implement at scale. As value can only be determined from the point of view of a stakeholder, it is likely that multiple sets of metrics will be needed, tailored to specific stakeholder needs. Moreover, economically based analyses or the use of specialists in the field are expensive and can happen only as resources permit.

Satellite remote sensing has been used extensively for many years to monitor the open oceans and coastal waters. These methods have been extended more recently to the study of inland waters. In this study we consider the potential application of data from two ocean color sensors, Moderate‐Resolution Imaging Spectroradiometer (MODIS) and Medium‐Resolution Imaging Spectrometer (MERIS), for monitoring the levels of suspended solids in small and intermediate sized lakes and reservoirs. We measured total suspended matter (TSM) in four southwestern United States lakes, Roosevelt Lake, Saguaro Lake, Bartlett Lake, and Lake Pleasant, and compared these field data with images obtained from these medium resolution satellite sensors. Our regression analysis of the complete data set identified a linear relationship between the field TSM values and both MODIS 250 m data (r2 = 0.461) and MERIS 290 m data (r2 = 0.521). This relationship improved substantially when data from the smallest lake in the study (Saguaro Lake) were excluded from the analysis (r2 = 0.819 and r2 = 0.888, respectively). The resultant linear models produced estimates with a root‐mean‐square error (RMSE) ranging from 3.14 mg/L (MODIS) and 2.04 mg/L (MERIS) for all four lakes combined, improving to 1.32 mg/L (MODIS) and 0.47 mg/L (MERIS) for a lake‐specific regression. These results suggest that these satellite sensors have the potential to effectively monitor TSM in lakes and reservoirs, although a minimum practical lake size does appear to exist.

In recent years, several studies have explored the potential of higher‐resolution sensor data for monitoring phytoplankton primary production in coastal areas and lakes. Landsat data have been used to monitor algal blooms [Chang et al., 2004; Vincent et al., 2004], and Moderate Resolution Imaging Spectroradiometer (MODIS) 250‐meter and Medium Resolution Imaging Spectrometer (MERIS) full‐resolution (300‐meter) bands have been utilized to detect cyanobacterial blooms [Reinart and Kutser, 2006] as well as to monitor water quality [Koponen et al., 2004].