A popular ENSO indicator, the southern oscillation index, can be adequately modelled at monthly resolution with an ARMA (1,8; 1) or a combined AR - ARCH model (Ahn and Kim, 2005). (gergs.net)
The GISS homepage formerly said: The NASA GISS Surface Temperature Analysis (GISTEMP) provides a measure of the changing global surface temperature with monthly resolution for the period since 1880, when a reasonably global distribution of meteorological stations was established. (climateaudit.org)
Daily and monthly resolution indices of the annular modes are available from the NOAA CPC. (atmos.colostate.edu)