Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Methodology:

Three drifting buoys (with ID numbers 103, 104, and 105) were deployed during the cruise to track the position of precipitation-receiving water masses (eddies) and simultaneously record temperature and salinity. The drifters were equipped with 10-m drogues and so approximately follow the surface mixed layer; the sensors were located at the depth of approximately 2 m.

Instruments:
Model 121 GPS / Iridium drifters by Brightwaters Instruments (BI) with temperature and salinity sensors (http://brightwaters.com/products/121/121.htm). Model 121 a current following (Lagrangian) drifting buoy, is released in a body of water and moves with the currents over a period of hours to months. Onboard electronics acquire a time series of positions using the Global Position System (GPS) as the drifter moves. Positions and optional sensor data are telemetered over the worldwide Iridium satellite network and delivered to the end user via a web browser. The DANCE drifters were configured with the “standard” size hull, which is approximately 1 meter (40 in.) tall excluding the antenna mast and weighs about 11 Kg (24 lbs). The Model 121 features a 12 channel GPS receiver and records position to 0.001 minute of latitude and longitude (1.8 meters). Absolute accuracy of the position is better than 15 meters worldwide. In areas served by one of three Satellite Based Augmentation Systems (WAAS in North America, EGNOS in Europe, and MSAS in East Asia) absolute accuracy is better than 3 meters 2DRMS. BI conductivity / temperature sensor: -10 to +40C, resolution 0.01C; 0-60 mmho/cm, resolution 0.01 mmho/cm; full digital sensor with individual calibration yields typical postprocessed accuracy of 0.05C and 0.05 mmho/cm.

Raw output was processed using Matlab.

BCO-DMO Data Manager Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* added ISO DateTime from year, month, day, hour, min, sec fields.
* NaN values displayed as "nd" for "no data"
* removed two lines containing bad lat/lon values

NSF abstract:

Deposition of atmospheric nitrogen provides reactive nitrogen species that influence primary production in nitrogen-limited regions. Although it is generally assumed that these species in precipitation contributes substantially to anthropogenic nitrogen loadings in many coastal marine systems, its biological impact remains poorly understood. Scientists from Pennsylvania State University, William & Mary College, and Old Dominion University will carry out a process-oriented field and modeling effort to test the hypothesis that deposits of wet atmospheric nitrogen (i.e., precipitation) stimulate primary productivity and accumulation of algal biomass in coastal waters following summer storms and this effect exceeds the associated biogeochemical responses to wind-induced mixing and increased stratification caused by surface freshening in oligotrophic coastal waters of the eastern United States. To attain their goal, the researchers would perform a Lagrangian field experiment during the summer months in coastal waters located between Delaware Bay and the coastal Carolinas to determine the response of surface-layer biogeochemistry and biology to precipitation events, which will be identified and intercepted using radar and satellite data. As regards the modeling effort, a 1-D upper ocean mixing model and a 1-D biogeochemical upper-ocean will be calibrated by assimilating the field data obtained a part of the study using the adjoint method. The hypothesis will be tested using sensitivity studies with the calibrated model combined with in-situ data and results from the incubation experiments. Lastly, to provide regional and historical context for the field measurements and the associated 1-D modeling, linked regional atmospheric-oceanic biogeochemical modeling will be conducted.

Broader Impacts. Results from the study would be incorporated into class lectures for graduate courses on marine policy and marine biogeochemistry. One graduate student from Pennsylvania State University, one graduate student from the College of William and Mary, and one graduate and one undergraduate student from Old Dominion University would be supported and trained as part of this project.