Growlers 

 157 



Figure 13. Breakdown of targets detected by IRD in 2000 



Oceanographic Operations 



Historically, IIP conducted extensive 

 oceanographic surveys on the Grand 

 Banks. Oceanographic operations peaked 

 in the 1960's when the Coast Guard 

 devoted substantial ship resources to 

 collecting oceanographic data. Two factors 

 combined to change the nature of HP's 

 oceanographic operations. First, increased 

 competition among the various Coast 

 Guard missions made it increasingly 

 difficult for IIP to obtain ship resources. 

 Second, there was a vast improvement in 

 the capability and reliability of deployable 

 oceanographic instruments. 



IIP collects oceanographic data with 

 satellite-tracked drifting buoys deployed by 

 aircraft or ship and Air-deployed 

 expendable BathyThermograph probes. 

 The drifters, popularly known as WOCE 

 (World Ocean Circulation Experiment) 

 buoys, are drogued at a depth of either 15 

 or 50 meters and provide valuable current 

 information. The historical current 

 database used by HP's computer model is 

 modified weekly using the current 

 information from the drifting buoys. 



During the 2000 season, IIP 

 deployed 13 satellite-tracked drifting 

 buoys, seven from reconnaissance aircraft, 

 and six from volunteer ships. Figure 14 

 shows composite tracks for the deployed 

 buoys. Two buoy recoveries were planned 

 but not attempted due to poor weather 

 conditions. Drifter information is provided 

 in MP's 2000 WOCE Buoy Drift Track Atlas, 

 available upon request. 



AXBT probes are dropped to 

 determine the water temperature profile. 

 This information helps IIP determine the 

 location of the Labrador Current, validate 

 temperatures from satellite-tracked drifting 

 buoys, and obtain precise SST 

 measurements for numerical models. 

 During the 2000 season IIP dropped 124 

 AXBT probes. Data was collected from 96 

 of the AXBT drops, a failure rate of 23%. 

 Figure 15 shows the development of HP's 

 AXBT program since 1996. IIP awarded a 

 contract in 1999 to replace the AXBT 

 receiver with a more reliable system. The 

 new system was tested and used 

 operationally during the 2000 season. The 

 results were encouraging but there is much 

 room for improvement. More experience 



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