Comparison of spatial downscaling methods of general circulation model results to study climate variability during the Last Glacial Maximum

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dc.contributor.authorLatombe, Guillaumeen_ZA
dc.contributor.authorBurke, Arianeen_ZA
dc.contributor.authorVrac, Mathieuen_ZA
dc.contributor.authorLevavasseur, Guillaumeen_ZA
dc.contributor.authorDumas, Christopheen_ZA
dc.contributor.authorKageyama, Masaen_ZA
dc.contributor.authorRamstein, Gillesen_ZA
dc.date.accessioned2018-08-13T11:45:57Z
dc.date.accessioned2021-08-30T10:08:42Z
dc.date.available2018-08-13T11:45:57Z
dc.date.available2021-08-30T10:08:42Z
dc.date.issued2018
dc.descriptionCITATION: Latombe, G. et al. 2018. Comparison of spatial downscaling methods of general circulation model results to study climate variability during the Last Glacial Maximum. Geoscientific Model Development, 11:2563–2579, doi:10.5194/gmd-11-2563-2018.
dc.descriptionThe original publication is available at https://www.geoscientific-model-development.net
dc.description.abstractThe extent to which climate conditions influenced the spatial distribution of hominin populations in the past is highly debated. General circulation models (GCMs) and archaeological data have been used to address this issue. Most GCMs are not currently capable of simulating past surface climate conditions with sufficiently detailed spatial resolution to distinguish areas of potential hominin habitat, however. In this paper, we propose a statistical downscaling method (SDM) for increasing the resolution of climate model outputs in a computationally efficient way. Our method uses a generalised additive model (GAM), calibrated over present-day climatology data, to statistically downscale temperature and precipitation time series from the outputs of a GCM simulating the climate of the Last Glacial Maximum (19 000–23 000 BP) over western Europe. Once the SDM is calibrated, we first interpolate the coarse-scale GCM outputs to the final resolution and then use the GAM to compute surface air temperature and precipitation levels using these interpolated GCM outputs and fine-resolution geographical variables such as topography and distance from an ocean. The GAM acts as a transfer function, capturing non-linear relationships between variables at different spatial scales and correcting for the GCM biases.We tested three different techniques for the first interpolation of GCM output: bilinear, bicubic and kriging. The resulting SDMs were evaluated by comparing downscaled temperature and precipitation at local sites with paleoclimate reconstructions based on paleoclimate archives (archaeozoological and palynological data) and the impact of the interpolation technique on patterns of variability was explored. The SDM based on kriging interpolation, providing the best accuracy, was then validated on present-day data outside of the calibration period. Our results show that the downscaled temperature and precipitation values are in good agreement with paleoclimate reconstructions at local sites, and that our method for producing fine-grained paleoclimate simulations is therefore suitable for conducting paleo-anthropological research. It is nonetheless important to calibrate the GAM on a range of data encompassing the data to be downscaled. Otherwise, the SDM is likely to overcorrect the coarse-grain data. In addition, the bilinear and bicubic interpolation techniques were shown to distort either the temporal variability or the values of the response variables, while the kriging method offered the best compromise. Since climate variability is an aspect of the environment to which human populations may have responded in the past, the choice of interpolation technique is therefore an important consideration.en_ZA
dc.description.versionPublisher's version
dc.format.extent17 pages
dc.identifier.citationLatombe, G. et al. 2018. Comparison of spatial downscaling methods of general circulation model results to study climate variability during the Last Glacial Maximum. Geoscientific Model Development, 11:2563–2579, doi:10.5194/gmd-11-2563-2018.en_ZA
dc.identifier.issn1991-959X (online)en_ZA
dc.identifier.otherdoi:10.5194/gmd-11-2563-2018
dc.identifier.urihttp://hdl.handle.net/10019.1/122795
dc.language.isoenen_ZA
dc.publisherCreative Commons Attribution 4.0 Licenseen_ZA
dc.rights.holderAuthors retain copyright
dc.subjectHominids -- Geographical distribution -- Historyen_ZA
dc.subjectClimatics changes -- Statisticsen_ZA
dc.subjectGeneral circulation modelsen_ZA
dc.subjectStatistical methodsen_ZA
dc.subjectKrigingen_ZA
dc.subjectKrigingen_ZA
dc.subjectStatistical methodsen_ZA
dc.subjectClimatics changes -- Statisticsen_ZA
dc.titleComparison of spatial downscaling methods of general circulation model results to study climate variability during the Last Glacial Maximumen_ZA
dc.typeArticleen_ZA
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