Table of Contents

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

Satellite-tracked drifters with holey sock drogues centered at 10, 15 and 40-m depths were deployed over Georges Bank during 1995-99 in support of the U.S. GLOBEC/Georges Bank Program.

References:
Christopher E. Naimie, Richard Limeburner, Charles G. Hannah and Robert C. Beardsley, 2001. On the geographic and seasonal patterns of the near-surface circulation on Georges Bank - from real and simulated drifters. Deep-Sea Research II: Topical Studies in Oceanography, vol 48, pp 501-518.

The status of drogue presence is indicated by timing the submergence of the surface float. When the drogue is attached, its drag will cause the surface sphere to submerge occasionally as a wave passes. If the drogue has been lost, the surface sphere remains at the surface and is not buried by waves. When the surface float submerges, contacts on top of the sphere are shorted out by the seawater and the PTT controller starts counting the length of time (seconds) the contacts are shorted. Every 30 minutes the accumulated submergence time is scaled by 0.1 (for example, 1000 seconds is scaled to 100) and loaded into the first byte of the data string and a new submergence time is started. Typical submergence values are 10 to 100. Consistent submergence values of 0 indicate the drogue has been lost. The maximum submergence value is 180 and indicates the surface float is sinking, or heavily fouled.

Those drifters with identifications starting with a "g" were generally deployed in US territorial waters and those with an "n" deployed in Canadian waters by the Bedford Institute of Oceanography.

All drifters originally submitted by this investigator, regardless of year deployed, had a year day value beginning with January 1, 1995 (year day of 1.0000). Thus, a deployment in 1996 had a year day >365.0000 and a deployment in 1999 had a deployment year day value >1461.0000 (1996 was a leap year). BCO-DMO converted those original year day values to standard yrday_gmt values (0 to 365, or 0 to 366 for leap years).

Based on dates of deployment and recovery, a drifter file may span two calendar years. The 'year_start' parameter indicates the year the drifter was deployed.

BCO-DMO made the following modifications: Calculated actual 'yrday_gmt' values from the original 'yrday_special' column (yrday_special = number of days since January 1, 1995); Added argosid and cruiseid from the 'drifters_start'_positions' dataset; Re-formatted all values from scientific notation to integers; Changed incorrect year values for drifter g96; Corrected the year value in cases where yrday_special and year did not match (e.g. if yrday_special was 367, but year was 1995, changed year to 1996); Changed values of '999.00' to 'nd' to indicate 'no data'; Removed data for drifter g162 because it was undergoing gps testing locally.

BCO-DMO corrected unknown/missing cruise ID's for the following drifters:
g31- corrected to EN274. (Cruise report for EN274 documents the deployment of g31.)
g47- corrected to EN278. (Original data has EN278 listed.)
g84 and g85 - corrected to EN291. (EN291 cruise report documents the deployment of these drifters.)
g98 and g99 - corrected to EN294. (EN294 cruise report documents the deployment of these drifters.)
g140 and g142 - corrected to EN300. (EN300 cruise report documents the deployment of these drifters.)
g157 and g158 - corrected to OC315. (Original data has OC315 listed and Oceanus schedule confirms dates, locations, and investigators.)
g159 - corrected to OC316. (Original data has OC316 listed and cruise report confirms this.)
n6 to n10 - corrected to PAR98-078. (Cruise report for PAR-98-078 documents the deployment of these drifters.)

The U.S. GLOBEC Georges Bank Program is a large multi- disciplinary multi-year oceanographic effort. The proximate goal is to understand the population dynamics of key species on the Bank - Cod, Haddock, and two species of zooplankton (Calanus finmarchicus and Pseudocalanus) - in terms of their coupling to the physical environment and in terms of their predators and prey. The ultimate goal is to be able to predict changes in the distribution and abundance of these species as a result of changes in their physical and biotic environment as well as to anticipate how their populations might respond to climate change.

The effort is substantial, requiring broad-scale surveys of the entire Bank, and process studies which focus both on the links between the target species and their physical environment, and the determination of fundamental aspects of these species' life history (birth rates, growth rates, death rates, etc).

Equally important are the modelling efforts that are ongoing which seek to provide realistic predictions of the flow field and which utilize the life history information to produce an integrated view of the dynamics of the populations.

The U.S. GLOBEC Georges Bank Executive Committee (EXCO) provides program leadership and effective communication with the funding agencies.

U.S. GLOBEC (GLOBal ocean ECosystems dynamics) is a research program organized by oceanographers and fisheries scientists to address the question of how global climate change may affect the abundance and production of animals in the sea.

The U.S. GLOBEC Program currently had major research efforts underway in the Georges Bank / Northwest Atlantic Region, and the Northeast Pacific (with components in the California Current and in the Coastal Gulf of Alaska). U.S. GLOBEC was a major contributor to International GLOBEC efforts in the Southern Ocean and Western Antarctic Peninsula (WAP).