Example: Change-point analysis (nonlinear regression).
Comparison of the oxygen isotope record from stalagmite Q5 (Oman),
a proxy for monsoon rainfall changes, with the smoothed (five-point running mean)
oxygen isotope record from the GRIP ice core (Greenland), an indicator of
North Atlantic air-temperature variations. Lower monsoon precipitation correlates with
colder North Atlantic temperature. The heavy lines show fitted
nonlinear 'ramp' functions as trend estimate.
Change-point times are given with their statistical errors (1 sigma),
which are estimated from bootstrap simulations.
Taking dating uncertainties for both the Q5 and GRIP records
into account (1% to 2%) shows that the changes occurred simultaneously. BP, before the present.
Source: Fleitmann D, Burns SJ, Mudelsee M,
Neff U, Kramers J, Mangini A, Matter A (2003)
Holocene forcing of the Indian monsoon recorded in a stalagmite from Southern Oman.
300:1737. External link to paper >>
Software: RAMPFIT. Climate change analysis software >>