Showing papers by "Rob Allan published in 2010"
TL;DR: In this article, the authors compare three independent NINO3.4 sea surface temperature (SST) reconstructions using data from (1) the central Pacific (corals), (2) the TexMex region of the USA (tree rings) and (3) other regions in the Tropics (CORals and an ice core) which are teleconnected with central Pacific SSTs in the 20th century.
Abstract: In this study we compare three newly developed independent NINO3.4 sea surface temperature (SST) reconstructions using data from (1) the central Pacific (corals), (2) the TexMex region of the USA (tree rings) and (3) other regions in the Tropics (corals and an ice core) which are teleconnected with central Pacific SSTs in the 20th century. Although these three reconstructions are strongly calibrated and well verified, inter-proxy comparison shows a significant weakening in inter- proxycoherenceinthe 19thcentury.Thisbreakdownin commonsignalcouldberelatedtoinsufficient data, dating errors in some of the proxy records or a breakdown in El Nino-Southern Oscillation's (ENSO's) influence on other regions. However, spectral analysis indicates that each reconstruction portraysENSO-likespectralproperties.Superposedepochanalysisalsoshowsthateachreconstruction shows a generally consistent 'El Nino-like' response to major volcanic events in the following year, while duringyearsT þ4toT þ7'La Nina-like'conditions prevail.Theseresults suggest thateachofthe series expresses ENSO-like 'behaviour', but this 'behaviour' does not appear to be spatially or temporally consistent. This result may reflect published observations that there appear to be distinct 'types' of ENSO variability depending on location within the tropical Pacific. Future work must address potential dating issues within some proxies (i.e. sampling of multiple coral heads for one location) as well as assessing the time stability of local climate relationships with central Pacific SSTs. More emphasis is needed on sampling new and extending old coral proxy records from the crucial central and eastern tropical Pacific region. Copyright # 2009 John Wiley & Sons, Ltd. and # Crown Copyright 2009.
156 citations
TL;DR: In the best-observed regions of the world around 150 years of direct instrumental observa-tions are available for climate research, but in large parts of the Southern Hemisphere records only cover the past 50-100 years as discussed by the authors.
Abstract: Our understanding of recent climate change hinges on the quality and length of histori-cal weather observations. In the best-observed regions of the world around 150 years of direct instrumental observa-tions are available for climate research, but in large parts of the Southern Hemisphere records only cover the past 50–100 years. This is despite the fact that weather obser-vations were routinely recorded by explora-tion, naval and merchant ship crews travelling the world during the eighteenth and nineteenth centuries (Garcia Herrera
11 citations