1. U.S. GLOBEC Long-Term Moored Array Data Jim Irish, Mike Caruso, Dick Limeburner, Bob Beardsley, Ken Brink Woods Hole Oceanographic Institution, Woods Hole, MA 02543 Introduction As part of the U.S. GLOBEC Northwest Atlantic/Georges Bank program, a long-term moored array was deployed and maintained on Georges Bank as part of the broad- scale survey component to help measure the long-term variability of both physical and biological characteristics on the Bank. The array consisted of a primary mooring site on the southern flank (SF) which was maintained for the full 5-year duration of the field program, plus secondary moorings, with fewer sensors and of shorter duration, in the well-mixed water on the crest (CR) and in the cod/haddock spawning region on the Northeast Peak (NEP). Temperature and conductivity (salinity) were measured at 5-m intervals, ADCP horizontal velocity profiles were obtained with 1-m vertical resolution, and bio-optical packages which measured fluoroescence, optical transmission and photosynthetically active radiation were deployed at 10-m and 40-m depths on selected moorings. The moored array data have now been reprocessed with final calibration checks and put into a standard file structure organized by mooring site, measurement depth and start date. The time series data are stored in MatLab mat-files with ASCII metadata files on the WHOI ftp site. This database also includes data from the 1995 Stratification Study moored array and the BIO long-term moored array component for completeness. This poster describes the composition and organization of the final moored array data set and provides directions on how to access this data via ftp using the Internet. Long-Term Moored Program Objectives: The GLOBEC Long-Term Moored Program deployed moorings at the Crest, Southern Flank and Northeast Peak sites of Georges Bank to describe the seasonal and interannual variability of the physical (and to a certain extent the biological) properties at these sites. Additionally, CTD sections were taken at deployment and recovery times (see Figure 1 and Table2). In collaboration with the broadscale shipboard surveys and more detailed process studies which took complementary observations, this project is addressing: 1. The spatial and temporal variability of the atmospheric forcing in the Georges Bank region and its relationship to the resulting water properties, stratification and circulation. 2. The variability of the temperature, salinity, velocity and pressure fields at the mooring sites. 3. The tides and internal tides, their relation to mixing on Georges Bank, and the location of the tidally mixed front. 4. The subtidal wind- and density-driven currents and their relation to the retention of organisms on the Bank. 5. The variability of biological indicators (photosynthetically active radiation (PAR), optical transparency, and chlorophyll-a fluorescence) at the moorings and their relation to the primary production and species abundance as observed from the broad-scale and process studies. 6. The effects of episodic events (storms, warm core rings, etc.) on the physical (and biological) properties at the mooring sites and the retention and loss of organisms from Georges Bank. Mooring configurations. Southern Flank (left), Northeast Peak (center) and Crest (right) showing the nominal sensor types and depths (specific configurations for each deployment are shown in timeline at left). ACKNOWLEDGMENTS U.S. GLOBEC is sponsored jointly by the National Oceanic and Atmospheric Administration and the National Science Foundation. The U.S. GLOBEC Georges Bank long-term moored effort is supported by NSF research grants OCE-93-13670, OCE-96-32348 and OCE-98-06445. This effort has required the assistance of many WHOI staff and groups as well as the captains and crews of the R/V ALBATROSS IV, ENDEAVOR, OCEANUS, SEWARD JOHNSON and local fishing vessels. We also want to thank our fellow GLOBEC scientists and technicians who are helping collect an extensive and unique database for analysis and synthesis efforts to come. Database structure The mooring database is designed to be directly accessible using a filesystem naming convention. Since the time-bases are variable between deployments and instrument packages, data files were created for each deployment, instrument and depth. Each data set is contained in a Matlab format file and has a corresponding text metadata file describing the contents of the data file. The top directory in the structure is split by mooring location: CR for the Crest site; NEP for the Northeast Peak site and SF for the Southern Flank site. Each of those directories is split into separate directories for each instrument package: ADCP for the Acoustic Doppler Current Profiler data, BIO for the Bio-Optical data, BP for the Bottom Pressure data, MET for the Meteorological data and TS for the Temperature/Salinity data. The directories are finally split into the starting year of the deployment. Each of these directories contains the Matlab format data files and the corresponding text metadata files. Each file is given a unique filename base on the deployment starting date, the instrument package, the deployment name and the instrument depth. For example, the file 19990310_TS_SF_005m.mat contains the temperature and salinity data at 5 m depth for the Southern Flank deployment that began on March 10, 1999. The metadata file is named using the same base as the data file, with a.txt extension. Variables within each data file are named for consistency wherever possible. Due to the fact that the time-base varies between deployment and instruments, subsurface temperatures are always T and salinities are always S, independent of instrument type or depth. The metadata file describes the contents of the corresponding data file, the processing history, the list of variables and any relevant notes. Directory structure CR MET 1994—1995 TS 1994—1995 NEP ADCP 1996—1999 BIO 1996—1999 MET 1995—1999 TS 1995—1999 SF ADCP 1996—1999 BIO 1997—1999 MET 1994—1999 TS 1994—1999 ftp://ftp.whoi.edu/pub/users/rcbshare/GB_Globec Data Archive Data Summary Bio-Optical Sensing Package: The in-line bio-optical package is shown with its designer - Paul Fucile. The recorder and batteries are in the long central black cylinder. At the top the LiCor spherical PAR sensor (looks like light bulb) measures total light for photosynthesis. Just below it and above the pressure case is a SeaTech 25 cm pathlength transmissometer. At the bottom left is a SeaTech chlorophyll-a fluorometer, and in the center, Sea Bird temperature and conductivity sensors. DATA SUMMARY Moored temperature and salinity data were collected on the Southern Flank, the Northeast Peak and the Crest of Georges Bank during the GLOBEC field effort starting in fall 1994 and continuing through the summer of 1999. [See time lines for mooring deployment times and data return.] These records reveal several important characteristics about the physical environment on Georges Bank.  There is considerable variability on tidal, day to week (intrusive events), seasonal, and inter-annual time scales.  The observed advection of different water masses through the mooring sites means that the “average” seasonal variation may not be a very useful description of the time variability of a parcel of water or at a locaton.  The large inter-annual variations make identification of long-term water property changes due to climate variability more difficult. The most significant long term trend observed is the freshening in the moored data during the 1994-1999 field effort that is also captured in the broad-scale hydrographic surveys, and is presumably associated in increased flow of Scotian Shelf water (decreased salinity) into the Gulf of Maine and onto Georges Bank (Smith et al., 1999).  Storms in fall and winter first mix the water column vertically as it cools. While the increase in solar heating in spring-summer starting in surface water varies smoothly in time, weather events in all seasons can influence the ner-surface stratification through both vertical mixing and horizontal advection.  Hurricane Edouard crossed over the Southern Flank site in late August 1996. A study of the effects of the hurricane clearly showed that advection of water was more important than vertical mixing in creating the observed water property evolution, and that advective effects are often the dominant process seen in the temperature and salinity records (Williams et al, 2001). a  Water properties on the Southern Flank and Northeast Peak are influenced by a number of events. These include intrusions of relatively cold fresh Scotian Shelf water (especially at the Northeast Peak site), warm salty Slope water and Gulf Stream Rings (especially at the Southern Flank site). The significant events (deviations from a smooth yearly heating/cooling, freshening/salting cycle) that occurred at the mooring sites are summarized in the GLOBEC Moored Event Table below. Locations of long-term moorings and CTD stations Southern Flank buoy. Bottom pressure instrument being deployed from the R/V Endeavor. Northeast Peak buoy ready to deploy from the R/V Knorr. Northeast Peak buoy. Temperature and Conductivity Sensors: Sea Bird SeaCats (top) and SBE-3 temperature and SBE-4 conductivity sensors (bottom). The temperature and conductivity sensors were mounted perpendicular to the electromechanical mooring cable in a PVC clamp on a length of garden hose to avoid sharp bending and chafing of the electrical or strength member. The horizontal orientation provides optimum flushing of the sensors. The SeaCats were mounted parallel with the mooring cable and tie wrapped and taped to the cable. The white tubes on the conductivity sensors are antifouling tubes to reduce biological induced drift in the conductivity observations. Moored In-Line ADCP: 300 kHz RD Instruments Workhorses ADCP were mounted on in-line frames and deployed just below the buoys. A short section of chain decoupled the buoy tilting motion from the ADCP. Auxiliary batteries are also mounted in the frame. The electromechanical mooring cable can be seen routed around the frame. Crest mooring fall 1995.