Observational Program 



Remote Sensing 



SLAR imagery guided the hydro- 

 graphic sampling program. The 

 IIP SLAR is an X-band (3-cm 

 wavelength), real-aperture radar 

 that produces a continuous 9-inch 

 (23 cm) analog (negative) image 

 on a dry-process film. Because 

 the IIP SLAR provides a negative 

 image, areas of intense radar 

 backscatter appear dark on the 

 film. These dark areas mark 

 regions where the sea surface is 

 rough with 2-cm waves. 



The aircraft, when flown at 8000 ft 

 (2438 m), maps a 50 km wide 

 swath on each side of the aircraft 

 with a blind spot ~5 km wide 

 directly under the aircraft (Figure 

 C-5). Both of the antennas are 

 vertically polarized. Navigational 

 information from the HC-130's 

 inertial navigation system (INS) is 

 printed directly on the film. 



Four aerial surveys, at approxi- 

 mately one-week intervals, 

 mapped the features in the study 

 area. The first survey (26 April 

 1986) covered 127,000 sq km 

 and identified a site to conduct the 

 hydrographic study. The three 

 subsequent flights (2, 9, and 17 

 May 1986) each mapped 56,000 

 sq km with overlapping coverage. 



On the last day of the experiment, 

 the Advanced Very High Resolu- 

 tion Radiometer (AVHRR) on the 

 NOAA 9 satellite provided the only 

 usable IR image of the area. 



Figure C-5 Geometry of the 

 internationai ice Patroi Side- 

 iooking airborne radar (SLAR). 

 Oniy one side is shown; the 

 radar transmits and receives on 

 both sides of the aircraft. 



Hydrography 



Hydrographic sampling 

 was divided into two phases. In 

 the first, 26 April to 3 May, EVER- 

 GREEN occupied 68 stations in a 

 18x26 km grid. At each station 

 water temperature and salinity 

 profiles of the upper 1 000 m of the 

 water column were made using an 

 internally-recording CTD. The 

 station pattern was based on in- 

 flight analyses of SLAR data. 

 After reprovisioning, EVER- 

 GREEN returned to the study area 

 for the second phase to repeat a 

 similar pattern, but a winch failure 

 after 28 CTD stations resulted in 

 continuing the survey using only 

 XBT's. 



Over the ranges encountered in 

 the study, the Neil Brown Inter- 

 nally-Recording CTD, has an 

 accuracy of 0.01 °C, 0.01 mmho 

 and 0.5% of full scale in pressure 

 up to 1000 dbar. Data were 

 sampled at 5Hz, which for the 

 50m/min lowering rate resulted in 

 conductivity, temperature and 

 pressure data being collected 

 every 0.2 dbar. Five scans of C,T, 

 and P were averaged and re- 

 corded internally at approximately 

 one dbar intervals. Salinity was 

 computed using an algorithm 

 based on Fofonoff (1985). 



The primary method of navigation 

 was LORAN-C, but when satellite- 

 tracked buoys were aboard, their 

 satellite-derived positions were 

 also used to fix the ship's position. 



C-130 (Side antenna) 



Transmitted 

 ^N, radar pulse 



\:^^<x — 



Azimuth 

 (flight) 

 8,000 ft \ V-X-V \ direction 



(2,438 m) \ \\ \ ^ 



'■ \\ \ -•^ 

 ' \ \ ."""V 



A \ 



Range'^-^~~-<45 

 (look) 

 direction ^ear 



range 



57 



