Data-model comparison using fuzzy logic in paleoclimatology

Guiot, Joël; Boreux, Jean-Jacques; Braconnot, Pascale; Torre, F. Jason

doi:10.1007/s003820050301

Cited by 50 publications

(31 citation statements)

References 39 publications

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“…In many previous model-data comparison studies (Cheddadi et al, 1997;Masson et al, 1999;Prentice et al, 1998;Guiot et al, 1999;Bonfils et al, 2004;Masson-Delmotte et al, 2006;Brewer et al, 2007) the climate variables considered are not summer, winter and annual mean temperature, but bioclimatic variables such as growing degree days, temperature of the coldest month and a humidity index that have been identified to better reflect the plant physiology. Most of the temperature reconstructions we used in this paper are indeed from bioclimatic proxies such as pollen, and this type of proxy mainly provides information of climate in summer.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…The mid-Holocene is one of the noticed warm periods that is well documented by proxy data and is often used to evaluate how models respond to a change primarily in insolation. Most of these data-model comparisons focus on proxy data rich areas such as southern and mid-latitude Europe (Liao et al, 1994;Harrison et al, 1998;Masson et al, 1999;Prentice et al, 1998;Guiot et al, 1999;Joussaume et al, 1999;Bonfils et al, 2004;Gladstone et al, 2005;Masson-Delmotte et al, 2006;Brewer et al, 2007). The high-latitude region is less often addressed due to the relative lack of proxy data compared to some other regions.…”

Section: Introductionmentioning

confidence: 99%

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Climate change between the mid and late Holocene in northern high latitudes – Part 2: Model-data comparisons

et al. 2010

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Abstract. The climate response over northern high latitudes to the mid-Holocene orbital forcing has been investigated in three types of PMIP (Paleoclimate Modelling Intercomparison Project) simulations with different complexity of the modelled climate system. By first undertaking model-data comparison, an objective selection method has been applied to evaluate the capability of the climate models to reproduce the spatial response pattern seen in proxy data. The possible feedback mechanisms behind the climate response have been explored based on the selected model simulations. Subsequent model-model comparisons indicate the importance of including the different physical feedbacks in the climate models. The comparisons between the proxy-based reconstructions and the best fit selected simulations show that over the northern high latitudes, summer temperature change follows closely the insolation change and shows a common feature with strong warming over land and relatively weak warming over ocean at 6 ka compared to 0 ka. Furthermore, the sea-ice-albedo positive feedback enhances this response. The reconstructions of temperature show a stronger response to enhanced insolation in the annual mean temperature than winter and summer temperature. This is verified in the model simulations and the behaviour is attributed to the larger contribution from the large response in autumn. Despite a smaller insolation during winter at 6 ka, a pronounced warming centre is found over Barents Sea in winter in the simulations, which is also supported by the nearby northern Eurasian continental and Fennoscandian reconstructions. This indicates that in the Arctic region, the response of the ocean and the sea ice to the enhanced summer insolation is more important for the winter temperature than the synchronous decrease of the insolation.

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Section: Summary and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Climate change between the mid and late Holocene in northern high latitudes – Part 2: Model-data comparisons

et al. 2010

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“…The studies by Masson et al (1998), Guiot et al (1999), and Bonfils et al (2004) all used the set of climate reconstructions of produced by Cheddadi et al (1997). As there are a number of differences between this reconstruction, and the estimations of Davis et al (2003) used in the current study, it is worth briefly describing them and discussing the implications for comparative studies.…”

Section: Choice Of Proxy Datamentioning

confidence: 98%

“…Liao et al, 1994;Harrison et al, 1998;Masson et al, 1998;Prentice et al, 1998;Guiot et al, 1999;Joussaume et al, 1999;Bonfils et al, 2004;Gladstone et al, 2005;Masson-Delmotte et al, 2006). The first generation PMIP model (PMIP1) runs were tested by Masson et al (1998) against a set of gridded climate reconstructions for the mid-Holocene in Europe (Cheddadi et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

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Mid-Holocene climate change in Europe: a data-model comparison

Brewer

Guiot

Torre³

2007

Clim. Past

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Abstract. We present here a comparison between the outputs of 25 General Circulation Models run for the midHolocene period (6 ka BP) with a set of palaeoclimate reconstructions based on over 400 fossil pollen sequences distributed across the European continent. Three climate parameters were available (moisture availability, temperature of the coldest month and growing degree days), which were grouped together using cluster analysis to provide regions of homogenous climate change. Each model was then investigated to see if it reproduced 1) similar patterns of change and 2) the correct location of these regions. A fuzzy logic distance was used to compare the output of the model with the data, which allowed uncertainties from both the model and data to be taken into account. The models were compared by the magnitude and direction of climate change within the region as well as the spatial pattern of these changes. The majority of the models are grouped together, suggesting that they are becoming more consistent. A test against a set of zero anomalies (no climate change) shows that, although the models are unable to reproduce the exact patterns of change, they all produce the correct signs of change observed for the mid-Holocene.

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A multiproxy record of late Holocene natural and anthropogenic environmental change from the Sphagnum peat bog Dürres Maar, Germany: implications for quantitative climate reconstructions based on pollen

Kühl

Moschen

Wagner

et al. 2009

J Quaternary Science

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Kü hl, N., Moschen, R., Wagner, S., Brewer, S. and Peyron, O. 2010. A multiproxy record of late Holocene natural and anthropogenic environmental change from the Sphagnum peat bog Dü rres Maar, Germany: implications for quantitative climate reconstructions based on pollen.ABSTRACT: Pollen data are well established for quantitative climate reconstructions over long timescales, including the Holocene and older interglacials. However, anthropogenically induced environmental change in central Europe was strong during the last 4 ka, challenging quantitative reconstructions of this time period. Here we present quantitative climate reconstructions based on pollen analyses and evaluate them with the peat humification record and the stable carbon isotopes of Sphagnum plant material (d 13 C cellulose ). All analyses were carried out on the same 7.5 m long, largely ombrotrophic peat bog section from Dü rres Maar. Three different methods were used for the quantitative climate reconstructions on the basis of the pollen data: (1) a probabilistic indicator taxa approach (the 'pdf method'); (2) a modern analogue technique based on pollen taxa from modern surface samples (cMAT); and (3) a modern analogue technique expanded by plant functional types (pMAT). At Dü rres Maar the peat humification is only affected by peat cutting during the Roman period and the Middle Ages. The stable carbon isotopes are seemingly unaffected by human impact. Thus both proxies provide independent data to evaluate the reconstructions on the basis of pollen data. The quantitative climate reconstructions on the basis of the individual methods are in general relatively similar. Nevertheless, distinct differences between the individual approaches are also apparent, which could be attributed to taxa that reflect human impact on a local to regional scale. While the pdf method appears to be relatively robust to all observed anthropogenically induced vegetation changes, it potentially underestimates climate variability. This method is therefore expected to be independent of local site characteristics and to provide robust quantitative estimates of climatic trends rather than of climatic variability of small amplitude. This is of value for palaeoclimate reconstructions of older interglacials, for which neither multiple sites nor independent climate proxies are available for comparison.

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Data-model comparison using fuzzy logic in paleoclimatology

Cited by 50 publications

References 39 publications

Climate change between the mid and late Holocene in northern high latitudes – Part 2: Model-data comparisons

Climate change between the mid and late Holocene in northern high latitudes – Part 2: Model-data comparisons

Mid-Holocene climate change in Europe: a data-model comparison

A multiproxy record of late Holocene natural and anthropogenic environmental change from the Sphagnum peat bog Dürres Maar, Germany: implications for quantitative climate reconstructions based on pollen

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