The Sashelp.ENSO (El Niño–Southern Oscillation) data set contains measurements of monthly averaged atmospheric pressure differences between Easter Island and Darwin, Australia, for a period of 168 months (National Institute of Standards and Technology 1998). These pressure differences drive the southern trade winds. This data set is used to illustrate fitting nonlinear functions to a scatter plot by using methods such as loess and penalized B-splines. These data show both seasonal variations and variations due to El Niño. The following steps display information about the Sashelp.ENSO data set and create Figure 52:
title 'El Nino Southern Oscillation Data';
proc contents data=sashelp.ENSO varnum;
ods select position;
run;
title 'The First Five Observations Out of 168';
proc print data=sashelp.ENSO(obs=5);
run;
Figure 52: El Niño–Southern Oscillation Data
| El Nino Southern Oscillation Data |
| Variables in Creation Order | |||
|---|---|---|---|
| # | Variable | Type | Len |
| 1 | Month | Num | 8 |
| 2 | Year | Num | 8 |
| 3 | Pressure | Num | 8 |
| The First Five Observations Out of 168 |
| Obs | Month | Year | Pressure |
|---|---|---|---|
| 1 | 1 | 0.08333 | 12.9 |
| 2 | 2 | 0.16667 | 11.3 |
| 3 | 3 | 0.25000 | 10.6 |
| 4 | 4 | 0.33333 | 11.2 |
| 5 | 5 | 0.41667 | 10.9 |