Table C-3. Characteristic Length of Iceberg Sizes 



from Fleet Numerical 

 Oceanography Center (FNOC) in 

 Monterey, CA. FNOC provides 

 SST data in °C and wave heights 

 in feet. For consistency, the 

 following discussion uses the 

 same units. 



Due to HP's reconnaissance 

 methods, iceberg length (not 

 mass) is the characteristic used to 

 evaluate deterioration. Each of 

 the four sizes of icebergs used by 

 IIP is assigned a characteristic 

 length based on our size 

 definitions (Table C-3). Before 

 each iceberg is eliminated from 

 our list of active icebergs because 

 of deterioration, it is allowed to 

 melt to 1 75% of its original length. 

 This figure, although selected 

 arbitrarily, is used conservatively 

 to ensure the iceberg has melted 

 before elimination. In order to 

 reduce this figure and still ensure 

 complete deterioration before an 

 iceberg is eliminated, field 

 measurements of the 

 deterioration of three icebergs 

 were observed during the 1 985 

 EVERGREEN cruise, one during 

 the first phase and two during the 

 second phase. Comparisons of 

 these observations to the 

 predictions of the deterioration 

 model are discussed below. 



The two icebergs observed 

 during the second phase of the 

 EVERGREEN cruise were used 

 as targets for a side-looking 

 airbome radar (SLAR) detection 

 and identification experiment 

 conducted between 27 April and 

 5 May 1985. Inorderforthe 

 iceberg to be tracked during the 

 SLAR experiment, it had to be 

 detectable up to at least 5 nm (9 

 km) on EVERGREEN'S surface 

 search radar. 



Figure C-5. Observed Vs. Model Predicted Iceberg Length 



ISO 



^ 140<>' 



£ 



C 



en 



c 



cr 



160 

 140 

 120 

 100 



80 



60 ^ 



40 



20 • 

 



'^''--»-.-,- 



.<^" 



«:;^3-^.t- Ql 



f>- ~- -^.^.^^-_. 



'-"•■•'•'• : :;.^; u.--\-"~'(jF^-^"=^<^Q ■ ,..,- .... 



* ma)or caVing event 

 I iceberg rollover/rlae 

 I 



.<>-...„ 



o 



Q predicted length 

 A observed length 

 ^ observed length 

 ■ observed length 



iceberg «1 



iceberg #2 



iceberg #3 



1 



Days After Initial Measurement 



Observed vs. remaining length predicted by Intemationai Ice Patrofs deterioration modet Observed wave tieight 

 and sea surface lemperatum were used as the model Inputs. The Mi narks Indicate observed Instances ol iceberg 

 rollover or rise whie the asterisks Indicais observed major caMng events. 



Fig. C-6. Iceberg #2 at 1000Z 28 April 1985. Est length 73m. 



64 



