Improving a plot-scale methane emission model and its performance at a northeastern Siberian tundra site

Mi, Y.; Huissteden, J. van; Parmentier, Frans‐Jan W.; Gallagher, A.; Budishchev, A.; Berridge, Callum; Dolman, A. J.

doi:10.5194/bg-11-3985-2014

Cited by 21 publications

(22 citation statements)

References 48 publications

(49 reference statements)

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“…Shrub encroachment lowers the tundra albedo and thus positively feeds back to global warming (Sturm et al, 2001b;Lawrence and Swenson, 2011;Loranty and Goetz, 2012). However, larger scale atmospheric effects do not explain variations of permafrost conditions at the local scale, where wetland vegetation is often associated with deeper active layers (Anisimov et al, 2002;Mi et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Contrasting radiation and soil heat fluxes in Arctic shrub and wet sedge tundra

et al. 2016

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Abstract. Vegetation changes, such as shrub encroachment and wetland expansion, have been observed in many Arctic tundra regions. These changes feed back to permafrost and climate. Permafrost can be protected by soil shading through vegetation as it reduces the amount of solar energy available for thawing. Regional climate can be affected by a reduction in surface albedo as more energy is available for atmospheric and soil heating. Here, we compared the shortwave radiation budget of two common Arctic tundra vegetation types dominated by dwarf shrubs (Betula nana) and wet sedges (Eriophorum angustifolium) in North-East Siberia. We measured time series of the shortwave and longwave radiation budget above the canopy and transmitted radiation below the canopy. Additionally, we quantified soil temperature and heat flux as well as active layer thickness. The mean growing season albedo of dwarf shrubs was 0.15 ± 0.01, for sedges it was higher (0.17±0.02). Dwarf shrub transmittance was 0.36 ± 0.07 on average, and sedge transmittance was 0.28 ± 0.08. The standing dead leaves contributed strongly to the soil shading of wet sedges. Despite a lower albedo and less soil shading, the soil below dwarf shrubs conducted less heat resulting in a 17 cm shallower active layer as compared to sedges. This result was supported by additional, spatially distributed measurements of both vegetation types. Clouds were a major influencing factor for albedo and transmittance, particularly in sedge vegetation. Cloud cover reduced the albedo by 0.01 in dwarf shrubs and by 0.03 in sedges, while transmittance was increased by 0.08 and 0.10 in dwarf shrubs and sedges, respectively. Our results suggest that the observed deeper active layer below wet sedges is not primarily a result of the summer canopy radiation budget. Soil properties, such as soil albedo, moisture, and thermal conductivity, may be more influential, at least in our comparison between dwarf shrub vegetation on relatively dry patches and sedge vegetation with higher soil moisture.

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Section: Introductionmentioning

confidence: 99%

Contrasting radiation and soil heat fluxes in Arctic shrub and wet sedge tundra

et al. 2016

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“…The model operates with classification defined by van Huissteden et al (2005) and has daily temporal resolution. For a detailed description of the model see Mi et al (2014).…”

Section: Peatland-vu Model Descriptionmentioning

confidence: 99%

“…The data collected by closed chamber method were published by van Huissteden et al (2005), van der Molen et al (2007) and van Huissteden et al (2009). The methane emission model was published by van Huissteden et al (2006) and Mi et al (2014).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a plot-scale methane emission model using eddy covariance observations and footprint modelling

Budishchev

Huissteden

et al. 2014

Biogeosciences

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Abstract. Most plot-scale methane emission models -of which many have been developed in the recent past -are validated using data collected with the closed-chamber technique. This method, however, suffers from a low spatial representativeness and a poor temporal resolution. Also, during a chamber-flux measurement the air within a chamber is separated from the ambient atmosphere, which negates the influence of wind on emissions.Additionally, some methane models are validated by upscaling fluxes based on the area-weighted averages of modelled fluxes, and by comparing those to the eddy covariance (EC) flux. This technique is rather inaccurate, as the area of upscaling might be different from the EC tower footprint, therefore introducing significant mismatch.In this study, we present an approach to validate plot-scale methane models with EC observations using the footprintweighted average method. Our results show that the fluxes obtained by the footprint-weighted average method are of the same magnitude as the EC flux. More importantly, the temporal dynamics of the EC flux on a daily timescale are also captured (r 2 = 0.7). In contrast, using the area-weighted average method yielded a low (r 2 = 0.14) correlation with the EC measurements. This shows that the footprint-weighted average method is preferable when validating methane emission models with EC fluxes for areas with a heterogeneous and irregular vegetation pattern.

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“…Some models have been developed only for smallscale applications (e.g. Xu et al, 2015;Mi et al, 2014;Khvorostyanov et al, 2008;Walter and Heimann, 2000) or use an empirical approach (e.g. Riley et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Process-based modelling of the methane balance in periglacial landscapes (JSBACH-methane)

et al. 2017

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Abstract. A detailed process-based methane module for a global land surface scheme has been developed which is general enough to be applied in permafrost regions as well as wetlands outside permafrost areas. Methane production, oxidation and transport by ebullition, diffusion and plants are represented. In this model, oxygen has been explicitly incorporated into diffusion, transport by plants and two oxidation processes, of which one uses soil oxygen, while the other uses oxygen that is available via roots. Permafrost and wetland soils show special behaviour, such as variable soil pore space due to freezing and thawing or water table depths due to changing soil water content. This has been integrated directly into the methane-related processes. A detailed application at the Samoylov polygonal tundra site, Lena River Delta, Russia, is used for evaluation purposes. The application at Samoylov also shows differences in the importance of the several transport processes and in the methane dynamics under varying soil moisture, ice and temperature conditions during different seasons and on different microsites. These microsites are the elevated moist polygonal rim and the depressed wet polygonal centre. The evaluation shows sufficiently good agreement with field observations despite the fact that the module has not been specifically calibrated to these data. This methane module is designed such that the advanced land surface scheme is able to model recent and future methane fluxes from periglacial landscapes across scales. In addition, the methane contribution to carbon cycleclimate feedback mechanisms can be quantified when running coupled to an atmospheric model.

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Improving a plot-scale methane emission model and its performance at a northeastern Siberian tundra site

Cited by 21 publications

References 48 publications

Contrasting radiation and soil heat fluxes in Arctic shrub and wet sedge tundra

Contrasting radiation and soil heat fluxes in Arctic shrub and wet sedge tundra

Evaluation of a plot-scale methane emission model using eddy covariance observations and footprint modelling

Process-based modelling of the methane balance in periglacial landscapes (JSBACH-methane)

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