cdm/src/main/java/ucar/nc2/dataset/conv/Cosmic1Convention.java
public double juday(int M, int D, int Y) {
    double JD;

    double IY = Y - (12 - M) / 10;
    double IM = M + 1 + 12 * ((12 - M) / 10);
    double I = IY / 100;
    double J = 2 - I + I / 4 + Math.round(365.25 * IY)
            + Math.round(30.6001 * IM);
    JD = (J + D + 1720994.50);
    return JD;
  }
public double juday(int M, int D, int Y) {
    double JD;

    double IY = Y - (12 - M) / 10;
    double IM = M + 1 + 12 * ((12 - M) / 10);
    double I = IY / 100;
    double J = 2 - I + I / 4 + Math.round(365.25 * IY)
            + Math.round(30.6001 * IM);
    JD = (J + D + 1720994.50);
    return JD;
  }
JDAY calculates the Julian Day number (JD) from the Gregorian month
,day, and year (M,D,Y). (NOT VALID BEFORE 10/15/1582)

@param M _more_
@param D _more_
@param Y _more_
@return _more_