Write multiple NumPy arrays into CSV file in separate columns?

How to write multiple numpy arrays into one csv file in multiple columns？

import numpy
import csv

arrA = numpy.array(file.root.a)
arrB = numpy.array(file.root.b)
arrC = numpy.array(file.root.c)

for i in range (480):
    for j in range (640):
        (write arrA[i,j] into column1,write arrB[i,j] into column2,write arrC[i,j] into column3)

Thanks a lot!