(1) ersst.VERSION.el_nino.dat
NINO indecies:
1st column: year
2nd column: month
3th column: NINO3	(K)
4rd column: NINO4	(K)
5th column: NINO3.4	(K)
6th column: NINO1.2	(K)

(2) ersst.VERSION.el_nino.sst.dat
same as in (1) except for full SSTs rather than anomalies.
Unit: C.

(3) ersst.VERSION.pdo.dat
PDO index in the format of
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec


Note: The anomalies are based on climatology from 1971 to 2000
      These indices are generated for the convenience of users. 
      They are not the official NOAA indices used for climate monitoring. (2015/1/15)