Category Archives: transfer function

The limits of high-resolution quantitative palaeoecology and Larocque-Tobler et al (2015)

The first quantitative palaeoclimate reconstructions from microfossil assemblages were low resolution, with a sample spacing of hundreds or thousands of years and focused on seasonal climate. Reconstructions focusing on a single month are now published at annual resolution. Can resolution … Continue reading

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50 chironomids or fewer – corrigendum for Larocque-Tobler et al 2015

Last year, Isabelle Larocque-Tobler and coauthors published a chironomid-inferred August air-temperature reconstruction for the 20th century from a Polish lake in Quaternary Science Reviews. The correlation between instrumental temperature records and the near-annual resolution reconstruction from Lake Żabińskie is remarkably … Continue reading

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Assessing performance and seasonal bias of pollen-based climate reconstructions in a perfect model world

With transfer functions (numerical methods for estimating environmental conditions from species assemblages), it is trivially easy to make reconstructions of many different climate variables. If you want to reconstruct December sunshine from pollen assemblages, simply train your model with December … Continue reading

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Significance testing testate amoeba water table reconstructions

Testate amoeba live in bogs, their shell or test is preserved in the peat after death. Some species seem to prefer drier conditions, others prefer wetter conditions. And thus we have the prerequisites for constructing a transfer function to reconstruct … Continue reading

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Estimating unbiased transfer-function performances in spatially structured environments

Mathias Trachsel and I have a paper in open discussion at Climate of the Past Discussions developing methods for estimating the performace of transfer functions in spatially autocorrelated environments. The paper began life as a blog post a couple of … Continue reading

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Limits to transfer function precision

Transfer functions are widely used to reconstruct past environmental conditions from fossil assemblages using the relationship between species and the environment in a modern calibration set. Naturally, palaeoecologists want to generate reconstructions that are as precise as possible, and take … Continue reading

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In eight-dimensional space, no one can hear your data scream

Mauri et al (2015) make a gridded climate reconstruction for Europe over the Holocene based on almost 900 pollen stratigraphies. The hope is that the reconstruction will be useful for evaluating climate models. This is a useful goal – if the climate models … Continue reading

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