Project Funding: 2012 - 2015

NRA: 2011 NASA: Terrestrial Ecology   

Funded by NASA

Abstract:
Peatland ecosystems represent 3-5% of the land surface, but sequester 12-30% of soil organic carbon (Gorham 1991). Current trends and climate models predict a general pattern of decreased water availability as a likely outcome of climate change. These climate changes can lead to increased amplitude of water table variation, including large mid-summer declines in water table height. Although peatlands have conventionally been considered resistant to wildfire due to their relatively wet soil conditions, recent studies have shown that the extent of wildfires in boreal North America, where peat fuels are common, has been steadily increasing in recent decades. The increasing extent of burning is likely due to warmer and drier climate conditions, which effectively extends the fire season and increases fire risk and subsequent CO2 emissions. Consumption of fuels and the subsequent emission of carbonaceous species into the atmosphere are dependent on fuel moisture content. Wetter fuels are more likely to exhibit smoldering combustion; this in turn has consequences for the quality of the remaining organics, as well as the composition of particulate emissions to the atmosphere. Understanding peat moisture content will enable an assessment of susceptibility and vulnerability to burning, ultimately allowing a means to model subsequent emissions. State-of-the-art remote sensing techniques are beginning to provide surface moisture maps over large areas. As such, datasets for a given platform may be able to provide surface moisture characteristics leading up to and following individual burning events in different peatlands. While there is a substantial literature describing drought codes and fuel moisture indexes in upland ecosystems, equivalent data describing thresholds for fire behavior in peatland ecosystems is lacking. Long-term surface peat moisture datasets derived from remote sensing data may indicate threshold conditions for severe and extensive peatland burning. However, key uncertainties associated with differences in peat structure, water table height, and moisture characteristics from thesedata have to be addressed. Taken together, coupling field assessments with remotely sensed data in recent and historically very severe burns will provide an understanding for the potential for scaling with each application. Considerable research has sought to characterize biomass combusted from wildfires via the remote measure of fire radiative energy (FRE). The utility of this approach is apparent given the availability of MODIS active fire products. Research has shown a strong relationship between FRE and the quantity of biomass combusted. However, FRE research has focused on fuels with low moisture contents, with increasing uncertainties apparent when rates of consumption are low. As a result experimental and modeling research is needed to quantify the uncertainty in using such products to infer consumption in wet fuels. Objectives: - Explore the utility of diverse sensor systems in detecting changes in peat moisture and moss spectral characteristics in relation to vegetation type, physical characteristics, and vegetation structure; - Characterize patterns of drying in diverse peatlands in the Great Lake States, Canada, and Alaska; - via experimental lab and field peatland fires, characterize the effect that moisture content has on FRE, and subsequently scale-up and model the impact of peatland fuel moisture on the ability of satellite based FRE products to infer biomass combusted; - Compare the carbonaceous emissions inferred from the FRE methodology to emission rates evaluated using common fire effects modeling systems [CONSUME/CANFIRE] and field data to independently evaluate the uncertainties in satellite and model based consumption estimates.

Publications:

Banskota, A., Falkowski, M. J., Smith, A. M. S., Kane, E. S., Meingast, K. M., Bourgeau-Chavez, L. L., Miller, M. E., French, N. H. 2017. Continuous Wavelet Analysis for Spectroscopic Determination of Subsurface Moisture and Water-Table Height in Northern Peatland Ecosystems. IEEE Transactions on Geoscience and Remote Sensing. 55(3), 1526-1536. DOI: 10.1109/TGRS.2016.2626460

Bourgeau-Chavez, L. L., Endres, S., Powell, R., Battaglia, M. J., Benscoter, B., Turetsky, M., Kasischke, E. S., Banda, E. 2017. Mapping boreal peatland ecosystem types from multitemporal radar and optical satellite imagery. Canadian Journal of Forest Research. 47(4), 545-559. DOI: 10.1139/cjfr-2016-0192

McPartland, M. Y., Kane, E. S., Falkowski, M. J., Kolka, R., Turetsky, M. R., Palik, B., Montgomery, R. A. 2018. The response of boreal peatland community composition and NDVI to hydrologic change, warming, and elevated carbon dioxide. Global Change Biology. 25(1), 93-107. DOI: 10.1111/gcb.14465

McPartland, M., Falkowski, M., Reinhardt, J., Kane, E., Kolka, R., Turetsky, M., Douglas, T., Anderson, J., Edwards, J., Palik, B., Montgomery, R. 2019. Characterizing Boreal Peatland Plant Composition and Species Diversity with Hyperspectral Remote Sensing. Remote Sensing. 11(14), 1685. DOI: 10.3390/rs11141685

Meingast, K. M., Falkowski, M. J., Kane, E. S., Potvin, L. R., Benscoter, B. W., Smith, A. M., Bourgeau-Chavez, L. L., Miller, M. E. 2014. Spectral detection of near-surface moisture content and water-table position in northern peatland ecosystems. Remote Sensing of Environment. 152, 536-546. DOI: 10.1016/j.rse.2014.07.014

Smith, A. M. S., Tinkham, W. T., Roy, D. P., Boschetti, L., Kremens, R. L., Kumar, S. S., Sparks, A. M., Falkowski, M. J. 2013. Quantification of fuel moisture effects on biomass consumed derived from fire radiative energy retrievals. Geophysical Research Letters. 40(23), 6298-6302. DOI: 10.1002/2013GL058232

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Continuous wavelet analysis for spectroscopic determination of sub-surface moisture and water-table height in northern peatland ecosystems   --   (Michael Falkowski, Asim Banskota, Evan S Kane, Alistair Matthew Stuart Smith, Laura Louise Bourgeau-Chavez, Nancy HF French)   [abstract]

2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• Fuel consumption and carbon cycling in northern peatland ecosystems: Understanding vulnerability to burning, fuel consumption, and emissions via remote sensing of fuel moisture and radiative energy   --   (Asim Banskota, Michael J. Falkowski, Evan S Kane, Alistair Matthew Stuart Smith, Robert Kremens, Nancy HF French, Laura Louise Bourgeau-Chavez, Mary Ellen Miller)   [abstract]   [poster]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile
• North American Carbon Program (NACP) Project Profile