Vertical cast water column conductivity, temperature, and depth (CTD) and auxiliary data collected in the Gulf of Mexico from May through September 2010

This report contains conductivity, temperature, depth (CTD), and auxiliary physiochemical sensor data (cumulatively referred to as “CTD data” herein) and provides additional context for the posted dataset, including information about the collection, analysis, and organization of the data. Characteristics of this dataset include the following: • This dataset consists of vertical cast water column CTD data collected as part of Response and NRDA efforts from May through September 9 of 2010. • This dataset includes CTD data from several cruises; data were collected cooperatively by the Trustees and BP or independently by the Trustees. • All data included in this posting were processed and validated cooperatively by Trustee and BP representatives. The focus of this data posting is vertical cast water column CTD data collected in the Gulf of Mexico from May through September 2010. This posting includes 13 studies encompassing 39 cruises and 829 CTD casts. These studies can be classified into three general categories: • NRDA Cooperative—Studies conducted as part of the NRDA which were agreed to and executed cooperatively by the National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Interior (DOI) and/or other Trustees, and BP. • Trustee Independent—Studies conducted by NOAA, DOI, and/or other Trustees independently to develop data to support and inform the NRDA. • Response (non-NRDA)—Studies conducted by BP and/or government representatives under the direction of the Unified Area Command and in association with activities performed in response to the DWH accident (the Response). The physical and chemical CTD data parameters provided in this data posting are as follows: • Conductivity • Temperature • Depth • Pressure • Salinity • Dissolved oxygen • Fluorescence • Turbidity • Chlorophyll • pH • Sound Velocity All water column CTD datasets include conductivity, temperature, depth, pressure, and salinity; the auxiliary sensor packages varied by work plan and/or vessel. To facilitate use of the CTD data, BP is providing processed data in the form of multiple data files and data types, specific to each individual cast. The various files associated with casts conducted during each cruise are compiled into a single zipped file folder, whenever practical. When not practical, overly large folders have been broken out into multiple zipped folders which are indicated by including an a, b, c, etc. at the end of each file name. A data posting station summary file has been provided to serve as an index for all studies and cruises and contains the coordinates for each CTD cast. Additionally, a PDF file containing CTD cast location maps for each cruise is provided to illustrate their spatial extent. The folder/file structure used in the report primarily identifies six file types: • Conversion data files (.cnv) • ASCII files (.asc) • Header files (.hdr) • Bottle summary files (.btl) • Rosette files (.ros) • Network common data form (netCDF) files (.nc) Due to the variety and unique combinations of sensors, the data fields and associated units may vary between cruises. The metadata presented here lists common field names/parameters stored in these files, a description of those parameters, and units.