from netCDF4 import Dataset
import numpy as np

Data = Dataset('Ice.nc','r')

ICE = np.squeeze(np.squeeze(Data.variables['sic'][:]))
Lat = Data.variables['latitude'][:]
Lon = Data.variables['longitude'][:]

Ice_Exten = np.zeros((360,180))


for i in range(0,360):
    for j in range(90,180):  #just northern hemisphere

        if ICE[j,i] > 0.15 and ICE[j,i] <= 1.0:

            Ice_Exten[i,j] = 12321. * np.cos(np.radians(j-90.))

print np.sum(Ice_Exten)/1e6