Geospatial representations of salinity monitoring site and bay and estuary group boundaries in the Gulf of Mexico

The polygon datasets were created to assist in visualizing the results of salinity modeling in Gulf of Mexico estuaries and bays. Statistical algorithms (Asquith and others, 2023) were developed to predict daily salinities for 91 salinity monitoring sites (Rodgers and Swarzenski, 2019) operated by 7 agencies in near coastal United States waters of the Gulf of Mexico. These monitoring sites are assigned to 15 salinity groups roughly corresponding to distinct bays and estuaries. The statistical algorithms facilitate the study of trends and drivers of salinity in near coastal waters. The groups polygon dataset consists of 15 polygons representing the outer boundary or hull of each of the 15 salinity groups. The sites polygon dataset consists of 91 polygons—one polygon per salinity monitoring site. The polygons were created using the Watershed Boundary Dataset, the National Hydrography Dataset, and aerial imagery. A detailed description of the polygon creation method is in the metadata processing steps. Creation of the polygons was motivated by a need to construct visual cues (maps and map animations) for testing the veracity of the statistical algorithms.

The polygon datasets described are suitable for visualizing broad trends and patterns in predicted daily salinity. These polygon datasets are not suitable for use in mass balance computations within a salinity group or for the broader near-coastal regions of the Gulf of Mexico and are not suitable as a basis for hydrodynamic or other process-based modeling.

This data release includes three attached files: (1) metadata .xml file, (2) .zip file containing shapefile of the 91 salinity site polygons, and (3) .zip file containing shapefile of the 15 salinity group polygons.