Pick of the Paperbacks; Ice Brothers, by Sloan Wilson. New York: Avon Books. $2.95.

This cleverly plotted and entertaining book begins in 1941, before the United States enters the war. The State Department calls on the Coast Guard to patrol Greenland's coasts because Germany has set up weather stations there and is sending weather forecasts to Nazi forces in Europe.

Set against the frozen adventures of the crew of a converted trawler is the story of Paul Schuman, whose adventures fighting the Germans are played out against his internal battles.

His personal life is complex. He has trouble at home with his vivacious young wife and his pushy older brother. He becomes involved with a Danish woman in exile. And aboard ship, Paul has bitter clashes with his loutish commanding officer.