in current systems. Likewise an abnormal atmospheric climate in 

 a given region will be reflected in the waters of that region. Weather 

 acts directly on ice causing immediate, noticeable changes in ice con- 

 ditions and exerts an indirect, more subtle and slower acting influence 

 on ice conditions by causing changes in the oceanographic environ- 

 ment. Changes in the relatively stable oceanographic factors are more 

 gradual, less various, and believed less effective overall than the fickle 

 meteorological elements in causing fluctuations in annual iceberg 

 conditions. - ^ - 



Let us take a closer look at the specific meteorological elements which 

 are assumed to significantly influence icebergs, their birth, lifetime 

 career, and death. Precipitation is believed to be an important ele- 

 ment only in the birth of bergs. Precipitation was necessary for the 

 formation of the Greenland Ice Cap in the first place, and is a factor 

 in the annual production of icebergs by their parent glaciers. Air 

 temperature is an important factor on the entire life of bergs-*t^ Air 

 temperatures influence the amount and type of precipitation and are 

 probably a factor in setting up stresses in iceberg- producing glaciers. 

 Air temperatures are important in helping to establish the environment 

 of bergs during their lifetime. Surface wind is also an important 

 influence on bergs from calving to destruction. Sea ice conditions 

 along the berg route are dependent mainly on air temperatures and, to 

 some degree. On .winds. It is a fact of life that a berg must travel most 

 of its long journey from glacier to the Grand Banks in protective pack 

 ice. Even large bergs in near- freezing open sea water cannot ordi- 

 narily last more than 3 to 4 months out of the pack ice. Winter air 

 temperatures at selected weather stations from Newfoundland to Baffin 

 Island are available. A comparison was made with the number of 

 icebergs south of 48° N. and the previous winter air temperatures, 

 expressed in freezing degree days to a base of 32° F., at selected weather 

 stations along the berg route for the past 8 years. ( See table IV. ) As 

 could be expected the correlation is good. Also, the surface wind, as 

 represented on U.S. Weather Bureau montlily sea level atmospheric 

 mean pressure charts, was analyzed for its probable effect on iceberg 

 drift toward the Grand Banks for each of the past 8 years. (See table 

 III.) Correlation with the number of bergs south of 48° N. each year 

 is remarkably excellent. Wliile the measurement of air temperatures, 

 expressed in freezing degree days or anomalies from normals, is 

 rather absolute, the measurement of the wind and evaluated effect on 

 iceberg drift south is far from absolute. Bottom topography is a very 

 important consideration as are other factors, and some assumptions 

 and judgments must be made. Yet it appears that the use of the 

 monthly average pressure distribution and its estimated influence on 

 iceberg drift offers the best correlation, and thus enables the most 

 accurate long-range forecast on the severity of the coming Grand 



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