| Code figure | Meaning |
| 0 | Unweighted mean of all members |
| 1 | Weighted mean of all members |
| 2 | Standard deviation with respect to cluster mean |
| 3 | Standard deviation with respect to cluster mean, normalized |
| 4 | Spread of all members |
| 5 | Large anomaly index of all members (see Note, below) |
| 6 | Unweighted mean of the cluster members |
| 7-191 | Reserved |
| 192-254 | Reserved for local use |
| 255 | Missing |
| Note: | Large anomaly index is defined as {(number of members whose anomaly is higher than 0.5*SD) - (number of members whose anomaly is lower than -0.5*SD)} / {number of members} at each grid point, where SD is defined as observed climatological standard deviation. |