code: public double areaNauticalMiles(Options options) {
          double topLatRads = Math.toRadians(topEdgeLatitude(options));
          double bottomLatRads = Math.toRadians(bottomEdgeLatitude(options));
  
          return Math.PI / 180 * radiusEarthKm * radiusEarthKm
                  * Math.abs(Math.sin(topLatRads) - Math.sin(bottomLatRads))
                  * options.getCellSizeDegreesAsDouble() / (KM_PER_NM * KM_PER_NM);
      }
docs: From http://mathforum.org/library/drmath/view/63767.html
  
  @param options
  @return