Iceberg #2 



A medium drydock iceberg was 

 located south of Flemish Cap in 

 position 46''1 2'N 46°1 4'W on 27 

 April during the second phase of 

 the EVERGREEN cruise (Figure 

 C-6) . The initial length of the 

 iceberg was approximately 75m. 

 Due to the highly irregular shape, 

 no quantitative estimates of the 

 mass were made. Due to fog, no 

 measurements were made on 29 

 April. The iceberg was observed 

 until 30 April when it no longer 

 was an acceptable target for the 

 SLAR experiment. 



During the observation period, 

 there were no observed incidents 

 of iceberg roll over. Major calving 

 events were observed on 27 April 

 and 30 April. The event of 30 

 April caused a considerable loss 

 of mass. The model predicted a 

 stower deterioration than was 

 actually observed (Figure C-5). 

 SST averaged about 1 .5°C while 

 the average wave height and 

 period were 3 feet and 4 seconds 

 for the obsen/ation period. 



Figure C-9. 



Iceberg #3 



The last iceberg observed during 

 the EVERGREEN cruise was a 

 small drydock iceberg located in 

 position 45°12"N 48°28*Won 1 

 May (Figure C-7). The initial 

 length and mass were 60m and 

 35,000 metric tons respectively. 

 Although this iceberg was never 

 obsen/ed to have rolled over, 

 there were frequent major calving 

 events. A calving between 2 and 



3 May caused a rise in the iceberg 

 resulting in an increase in water- 

 line length. The model does a fair 

 job of predicting the deterioration 

 rate until day 4 (5 May) when a 

 major calving event significantly 

 reduced the size of the icelserg 

 (Figure C-5). On 5 May, the ice- 

 berg calved 7 large pieces of ice 

 with the largest being 20m in 

 length and having a mass of 

 about 4,000 metric tons. The 

 mass of the iceberg after this 

 event was reduced to about 

 8,000 metric tons. The average 

 signif leant wave heigfit fortfie 

 duration of the otjser-vations was 



4 feet with a 5- to 6-second 

 period. SST averaged about 

 1.0°C. 



Observed vs. FNOC predicted wave heights. 



Note the consistent over-estimation of wave height by FNOC 

 for the obsen/ed period. 



25 



S- 20 



g> 15 

 o 



X 

 g 10 



5 



/ 



N. 



PREDICTED 

 OBSERVED 



\ 



A 



J 



\ 



V 



16 17 IS 1S 20 21 22 23 24 25 26 27 28 20 30 1 



S Dates Of Observation (1985) S 



Observed vs. FNOC 

 Environmental Model 

 Inputs 



Comparisons were made 

 between the observed and 

 FNOC SST and wave height data. 

 Six hour averages before the 

 synoptic hour of the observed 

 data were used in thie 

 comparisons below. The FNOC 

 SST is reasonably close to the 

 observed data (Figure C-8). The 

 largest difference was 0.4°C. The 

 magnitude of this difference is 

 consistent with past comparisons 

 (Anderson, 1983). Thechange 

 in FNOC SST between 30 April 

 and1 May was due to 

 EVERGREEN'S change in 

 position as k^berg #2 

 deteriorated substantially and 

 fceberg #3 was located (Figure C- 

 5). The largest error of 2.5°C 

 occurred during the observation 

 of iceberg #3 on 1 May. 



The highest waves observed 

 during the EVERGREEN cruise 

 were 8 feet on 1 8 April (Figure C- 

 9). FNOC predicted the wave 

 height for EVERGREEN'S 

 position on 1 8 April to be 25 feet. 

 The observed wave heights 

 never were greater than one half 

 of the wave height predated by 

 FNOC with the average error 

 being about 10 feet. These 

 differences between the 

 predicted and ot3sen/ed wave 

 heights are consistent with 

 comparisons made by IIP in 

 previous years (Anderson, 1983). 



66 



