Caspar M Ammann | PubMed Health

PubMed2006

Comment on "Reconstructing past climate from noisy data".

von Storch et al. (Reports, 22 October 2004, p. 679) criticized the ability of the "hockey stick" climate field reconstruction method to yield realistic estimates of past variation in Northern Hemisphere temperature. However, their conclusion was based on incorrect implementation of the reconstruction procedure. Calibration was performed using detrended data, thus artificially removing a large fraction of the physical response to radiative forcing.

Comment↗

PubMed2003

Proxy evidence for an El Niño-like response to volcanic forcing.

Past studies have suggested a statistical connection between explosive volcanic eruptions and subsequent El Niño climate events. This connection, however, has remained controversial. Here we present support for a response of the El Niño/Southern Oscillation (ENSO) phenomenon to forcing from explosive volcanism by using two different palaeoclimate reconstructions of El Niño activity and two independent, proxy-based chronologies of explosive volcanic activity from ad 1649 to the present. We demonstrate a significant, multi-year, El Niño-like response to explosive tropical volcanic forcing over the past several centuries. The results imply roughly a doubling of the probability of an El Niño event occurring in the winter following a volcanic eruption. Our empirical findings shed light on how the tropical Pacific ocean-atmosphere system may respond to exogenous (both natural and anthropogenic) radiative forcing.

Journal Article↗