Continuous fields of vegetation characteristics at the global scale at 1‐km resolution

DeFries, Ruth; Townshend, J. R. G.; Hansen, M.

doi:10.1029/1999jd900057

Cited by 207 publications

(148 citation statements)

References 39 publications

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“…The JULES model also uses PFT distributions derived from the IGBP DISCover data set to estimate fractional coverage of five PFTs and four non-vegetated surfaces (water, urban, snow/ice and bare soil). JSBACH uses original data from Wilson and Henderson-Sellers (1985) and continuous tree fractions from DeFries et al (1999) to represent the distribution and abundance of 12 PFTs. The LC_CCI Epoch 2010 was converted to 0.5 degree resolution using the LC_CCI user tool and compared with the individual default model PFT maps to illustrate regional differences and biases between products and to provide a baseline of how the LC_CCI products may improve LSM performance.…”

Section: Analysis and Comparison To Pft Mapsmentioning

confidence: 99%

Plant functional type classification for earth system models: results from the European Space Agency's Land Cover Climate Change Initiative

et al. 2015

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Abstract. Global land cover is a key variable in the earth system with feedbacks on climate, biodiversity and natural resources. However, global land cover data sets presently fall short of user needs in providing detailed spatial and thematic information that is consistently mapped over time and easily transferable to the requirements of earth system models. In 2009, the European Space Agency launched the Climate Change Initiative (CCI), with land cover (LC_CCI) as 1 of 13 essential climate variables targeted for research development. The LC_CCI was implemented in three phases: first responding to a survey of user needs; developing a global, moderate-resolution land cover data set for three time periods, or epochs (2000, 2005, and 2010); and the last phase resulting in a user tool for converting land cover to plant functional type equivalents. Here we present the results of the LC_CCI project with a focus on the mapping approach used to convert the United Nations Land Cover Classification System to plant functional types (PFTs). The translation was performed as part of consultative process among map producers and users, and resulted in an open-source conversion tool. A comparison with existing PFT maps used by three earth system modeling teams shows significant differences between the LC_CCI PFT data set and those currently used in earth system models with likely consequences for modeling terrestrial biogeochemistry and land-atmosphere interactions. The main difference between the new LC_CCI product and PFT data sets used currently by three different dynamic global vegetation modeling teams is a reduction in high-latitude grassland cover, a reduction in tropical tree cover and an expansion in temperate forest cover in Europe. The LC_CCI tool is flexible for users to modify land cover to PFT conversions and will evolve as phase 2 of the European Space Agency CCI program continues.

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Section: Analysis and Comparison To Pft Mapsmentioning

confidence: 99%

Plant functional type classification for earth system models: results from the European Space Agency's Land Cover Climate Change Initiative

et al. 2015

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“…To obtain this important information from the fossil pollen record we used a new approach for woody cover reconstruction (Tarasov et al, 2007b). The method combines extensive modern surface pollen and satellite-based Advanced Very High Resolution Radiometer (AVHRR) datasets from northern Eurasia (DeFries et al, 1999;Tarasov et al, 2007b) with the best modern analogue (BMA) approach (Overpeck et al, 1985;Guiot, 1990), allowing fossil pollen samples to be attributed to the vegetation characteristics associated with their closest modern pollen analogues. In this study the AVHRR-based estimates of woody cover percentages within a 21×21 km window around pollen sampling sites were attributed to the KTK1 pollen spectra (see Tarasov et al, 2007b for the method evaluation and design).…”

Section: Pollen-based Vegetation and Climate Reconstructionmentioning

confidence: 99%

Late Glacial and Holocene changes in vegetation cover and climate in southern Siberia derived from a 15 kyr long pollen record from Lake Kotokel

2009

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Abstract. In this study a radiocarbon-dated pollen record from Lake Kotokel (52 • 47 N, 108 • 07 E, 458 m a.s.l.) located in southern Siberia east of Lake Baikal was used to derive quantitative characteristics of regional vegetation and climate from about 15 kyr BP (1 kyr=1000 cal. yr) until today. Quantitative reconstruction of the late glacial vegetation and climate dynamics suggests that open steppe and tundra communities predominated in the study area prior to ca. 13.5 kyr BP and again during the Younger Dryas interval, between 12.8 and 11.6 kyr BP. The pollen-based climate reconstruction suggests lower-than-present mean January (∼−38 • C) and July (∼12 • C) temperatures and annual precipitation (∼270-300 mm) values during these time intervals. Boreal woodland replaced the primarily open landscape around Kotokel three times at about 14.8-14.7 kyr BP, during the Allerød Interstadial between 13.3-12.8 kyr BP and with the onset of the Holocene interglacial between 11.5 and 10.5 kyr BP, presumably in response to a noticeable increase in precipitation, and in July and January temperatures. The maximal spread of the boreal forest (taiga) communities in the region is associated with a warmer and wetter-than-present climate (T w ∼17-18 • C, T c ∼−19 • C, P ann ∼500-550 mm) that occurred ca. 10.8-7.3 kyr BP. During this time interval woody vegetation covered more than 50% of the area within a 21×21 km window around the lake. The pollen-based best modern analogue reconstruction suggests a decrease in woody cover percentages and in all cliCorrespondence to: P. E. Tarasov (ptarasov@zedat.fu-berlin.de) matic variables about 7-6.5 kyr BP. Our results demonstrate a gradual decrease in precipitation and mean January temperature towards their present-day values in the region around Lake Kotokel since that time.

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“…Attempts have been made recently to characterize land cover carried out by estimating the proportions of cover types present within each pixel using techniques such as linear mixture modelling (Gong et al 1991, Asner et al 1997, DeFries et al 1999.…”

Section: Introductionmentioning

confidence: 99%

Beware of per-pixel characterization of land cover

Townshend¹,

Huang²,

Kalluri³

et al. 2000

International Journal of Remote Sensing

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175

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Abstract.A simulation experiment was carried out to analyse the e ects of the modulation transfer function on our ability to estimate the proportions of land cover within a pixel by linear mixture modelling. In the simulated landscape the proportion of each land cover type in every pixel was known exactly. The standard error of the estimate (SEE) between percentages derived from mixture modelling and the actual land cover percentages was 11%. Substantial improvements in estimating the percentages can be obtained simply by deriving estimates for pixels of twice the original dimensions, the SEE dropping to 4.16%, though this is with the obvious consequence of a nal product with a coarser spatial resolution. Alternatively by deconvolving the input bands using a linear approximation of the point spread function the SEE can be reduced by almost as much, namely to 5.11%. If we combine the two approaches, by rst doconvolving the bands, estimating the percentages and then aggregating resultant pixels to twice their original linear dimensions, the SEE drops to 2.24%.

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Continuous fields of vegetation characteristics at the global scale at 1‐km resolution

Cited by 207 publications

References 39 publications

Plant functional type classification for earth system models: results from the European Space Agency's Land Cover Climate Change Initiative

Plant functional type classification for earth system models: results from the European Space Agency's Land Cover Climate Change Initiative

Late Glacial and Holocene changes in vegetation cover and climate in southern Siberia derived from a 15 kyr long pollen record from Lake Kotokel

Beware of per-pixel characterization of land cover

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