viirs.py 文件源码

def gain_factor(theta):
        gain = np.empty_like(theta)

        mask = theta <= 87.541
        gain[mask] = (58 + 4 / np.cos(np.deg2rad(theta[mask]))) / 5

        mask = np.logical_and(theta <= 96, 87.541 < theta)
        gain[mask] = (123 * np.exp(1.06 * (theta[mask] - 89.589)) *
                      ((theta[mask] - 93)**2 / 18 + 0.5))

        mask = np.logical_and(96 < theta, theta <= 101)
        gain[mask] = 123 * np.exp(1.06 * (theta[mask] - 89.589))

        mask = np.logical_and(101 < theta, theta <= 103.49)
        gain[mask] = (123 * np.exp(1.06 * (101 - 89.589)) *
                      np.log(theta[mask] - (101 - np.e)) ** 2)

        gain[theta > 103.49] = 6.0e7

        return gain