HadCRUT3
----------------------------
Data are stored in ASCII

All values are stored as temperature anomalies in degrees celsius
Missing data are set to the value given in the header. (normally -1.0e-30)

Grids are 5x5deg monthly

The day (irrelevent here), month and year are stored at the start of each month.

Data Array (72x36)
Item (1,1) stores the value for the 5-deg-area centred at 177.5W and 87.5N
Item (72,36) stores the value for the 5-deg-area centred at 177.5E and 87.5S

          ----- ------ ------------------------------
         |     |      |     |      |       |         |
         | YR  |  MON | DAY | ROWS | COLS  |         |
         |_____|______|_____|______|_______|_________|__
     90N |(1,1)                                         |
         |                                              |
         |                                              |
         |                                              |
         |                                              |
         |(1,18)                                        |
     Equ |                                              |
         |(1,19)                                        |
         |                                              |
         |                                              |
         |                                              |
         |                                              |
     90S |(1,36)_________________________________(72,36)|
          180W                 0                    180E