Application of artificial neural networks to paleoceanographic data

Malmgren, Björn A.; Nordlund, Ulf

doi:10.1016/s0031-0182(97)00031-x

Cited by 104 publications

(58 citation statements)

References 19 publications

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“…For the purpose of salinity estimations it was decided to use the Artificial Neuronal Network technique (ANN; Malmgren, Nordlund 1997). In spite of rare usage of ANN in micropalaeontological studies, however, it provides good results considered to be better estimate than statistical methods as for example Imbrie and Kipp Method (IKM) or Modern Analogue Technique (MAT; Chen et al 2005).…”

Section: Methodsmentioning

confidence: 99%

“…The ANN was found to be applicable for gas and oil exploration, in military techniques, in medicine or economy. For palaeoceanographic purposes the ANN was initially tested and applied by Malmgren and Nordlund (1997).…”

Section: Methodsmentioning

confidence: 99%

“…The learning sequence known as back propagation or propagation of error of ANN, which was applied to these studies, is processed by an algorithm that works by what is known as supervised training (Malmgren, Nordlund 1997). Firstly an input is transferred for a forward pass through the network.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Anomalous radioactivity level and high concentrations of heavy minerals in Lemme area, South-West Estonia

Raukas

Koch

Jüriado

et al. 2014

Baltica

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As early as in the 1960s, extensive heavy-mineral concentrations containing zircon, monazite, and xenotime were discovered in the Lemme region of south-western Estonia. These concentrations contribute to the elevated radioactivity levels of the enclosing sediments. The near shore sands of the Litorina Sea contain up to 10-cm-thick interlayers with a heavy mineral content of up to 80%. These anomalous layers were formed during the transgressive phase and result from a complicated cross-and alongshore migration of sedimentary material, derived mainly from local Devonian bedrock. Radioactivity level in the study area is higher relative to the majority of the Devonian plateau. The Lemmeoja buried soil has 13 radiocarbon dates in an area of renewed interest for the investigation of the Baltic Sea history.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Anomalous radioactivity level and high concentrations of heavy minerals in Lemme area, South-West Estonia

Raukas

Koch

Jüriado

et al. 2014

Baltica

View full text Add to dashboard Cite

show abstract

“…Although extremely different in their numerical computations and algorithms, artificial neural networks (ANN) have identical mathematical properties when applied to palaeoenvironmental reconstructions. Malmgren and Nordlund (1997), Malmgren et al (2001), Burrows et al (2005), and Kucera et al (2005) describe the use of ANN in marine sea-surface temperature reconstructions; Peyron et al (1998Peyron et al ( , 2000Peyron et al ( , 2005, Tarasov et al (1999aTarasov et al ( , 1999b, and Guiot et al (1996) provide examples of their use with terrestrial pollen data; and Racca et al (2001; discuss ANN applications in palaeolimnology. Telford and Birks (2005) show that in crossvalidation tests with a truly independent test-set, MAT and ANN perform poorly as both involve estimating smooth local functions.…”

Section: The Assemblage Approach Basic Principlesmentioning

confidence: 99%

Strengths and Weaknesses of Quantitative Climate Reconstructions Based on Late-Quaternary Biological Proxies

Birks

2011

TOECOLJ

343

284

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Abstract:The importance of reconstructing past environments quantitatively in palaeoecology is reviewed by showing that many ecological questions asked of palaeoecological data commonly involve the reconstructions of past environment. Three basic approaches to reconstructing past climate from palaeoecological data are outlined and discussed in terms of their assumptions, strengths, and weaknesses. These approaches are the indicator-species approach involving bioclimateenvelope modelling; the assemblage approach involving modern analogue techniques and response surfaces; and the multivariate calibration-function approach. Topics common to all approaches are reviewed -presentation and interpretation, evaluation and validation, comparison, and general limitations of climate reconstructions. Challenges and possible future developments are presented and the potential future role of quantitative climate reconstructions in palaeoecology is summarised.

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“…The ANN method relies upon the abundances of members of a suite of planktonic foraminifera in order to provide quantitative SST information. A description of this technique can be found in Malmgren and Nordlund (1997).…”

Section: Other Site 723 Recordsmentioning

confidence: 99%

Tropical climate variability from the last glacial maximum to the present

Dahl¹

2005

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This thesis evaluates the nature and magnitude of tropical climate variability from the Last Glacial Maximum to the present. The temporal variability of two specific tropical climate phenomena is examined. The first is the position of the Intertropical Convergence Zone (ITCZ) in the Atlantic basin, which affects sea surface temperature (SST) and precipitation patterns throughout the tropical Atlantic. The second is the strength of the Indian Monsoon, an important component of both tropical and global climate.Long-term variations in the position of the ITCZ in the Atlantic region are determined using both organic geochemical techniques and climate modeling. Upwelling in Cariaco Basin is reconstructed using chlorin steryl esters as proxies for phytoplankton community structure. We find that the diatom population was larger during the Younger Dryas cold event, indicating that upwelling was enhanced and the mean position of the ITCZ was farther south during the Younger Dryas than it is today. A climate simulation using an ocean-atmosphere general circulation model confirms these results by demonstrating that the ITCZ shifts southward in response to high-latitude cooling.The climate of the Arabian Sea region is dominated by the Indian Monsoon. Results from modern sediments from a suite of cores located throughout the Arabian Sea suggest that wind strength is well represented by the accumulation rate and carbon isotopic composition of terrestrially-derived plant waxes in sediments. Arabian Sea SST patterns, reconstructed from a suite of sediment cores representing four time slices utilizing the Mg/Ca SST proxy, suggest that both the summer and winter monsoons were enhanced 8,000 yr BP relative to today while the summer monsoon was weaker and the winter monsoon stronger at 15,000 and 20,000 yr. These results are confirmed by a time-series reconstruction of SST on the Oman Margin that reveals that SST at this site is sensitive to both regional and global climate processes. The results of this thesis demonstrate that tropical climate, as evaluated by a number of different proxies as well as climate models, has varied substantially over the past 20,000 years and is closely coupled to climate at high-latitudes. sharing ideas, opinions, and enthusiasm. Dan Repeta was the first to offer me the opportunity to come to WHOI and for that opportunity I will always be grateful. This thesis would have taken me double the time if not for the help of many assistants.

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Application of artificial neural networks to paleoceanographic data

Cited by 104 publications

References 19 publications

Anomalous radioactivity level and high concentrations of heavy minerals in Lemme area, South-West Estonia

Anomalous radioactivity level and high concentrations of heavy minerals in Lemme area, South-West Estonia

Strengths and Weaknesses of Quantitative Climate Reconstructions Based on Late-Quaternary Biological Proxies

Tropical climate variability from the last glacial maximum to the present

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