how to deal with the array in the case of large files!

Dear all,

I have 18 different 3D gridded models( with 74cells in x, 63 cells in y, and 30 cells in z direction for each model).I want to do some operation on these data so, I loaded  all of data in memory as jagged array: A[][,,] in which the first jagged part is iterating for 18 different model, and second jegged part is the location of each cell.

But the problem is that I will need a huge memory ( since we need 18*74*63*30 array element=high memory)*!! Is there any other way to handle these data? for example is it possible to store data in an external file (like excel, or TXT) and each time refer to the  excel cells( or the data in the TXT file) we need and do the calculation? ( in this way we do not need to have all of the data in memory since each time we may need to make calculation on a part of the cells)

I will appreciate your kind Reply