Lori Thompson Sentman
Research Interests
Developing and using comprehensive climate and biosphere models of the atmosphere-ocean-ice-land system to identify and elucidate physical, biogeochemical and ecological mechanisms, asses and understand the predictability of the Earth system on seasonal and longer time scales, and evaluate the impact of anthropogenic activity on the Earth system.
Research Activities
- interactions and feedbacks of climate on the terrestrial biosphere carbon cycle
- impact of land use change on the terrestrial biosphere carbon stores and fluxes
- sensitivity of the terrestrial biosphere carbon cycle to atmospheric initial conditions
Key Publications
Shevliakova, E., S. W.
Pacala, S. Malyshev, G. C. Hurtt, P.C.D. Milly, J. P. Caspersen, L. T.
Sentman, J. P. Fisk, C. Wirth, and C. Crevoisier (2009), Carbon Cycling under 300 Years of Land-use Change: the Importance of the Secondary Vegetation Sink, Global Biogeochem. Cycles,
doi:10.1029/2007GB003176, in press. [ Abstract PDF]We have developed a dynamic land model (LM3V) able to simulate ecosystem dynamics and exchanges of water, energy and CO2 between land and atmosphere. LM3V is
specifically designed to address the consequences of land-use/land-management changes
including cropland and pasture dynamics, shifting cultivation, logging, fire, and resulting
patterns of secondary regrowth. Here we analyze the behavior of LM3V, forced with the
output from the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric model
AM2, observed precipitation data and four historic scenarios of land-use change for
1700-2000. Our analysis suggests a net terrestrial carbon source due to land-use activities
from 1.1 to 1.3 GtC/yr during the 1990s, where the range is due to the difference in the
historic cropland distribution. This magnitude is substantially smaller than previous
estimates from other models, largely due to our estimates of a secondary vegetation sink
of 0.35 to 0.6 GtC/yr in the 1990s and decelerating agricultural land clearing since
the1960s. For the 1990s, our estimates for the pastures carbon flux vary from a source of
0.37 to a sink of 0.15 GtC/yr, and for the croplands our model shows a carbon source of
0.6 to 0.9 GtC/yr. Our process-based model suggests a smaller net deforestation source
than earlier bookkeeping models because it accounts for decelerated net conversion of
primary forest to agriculture and for stronger secondary vegetation regrowth in tropical
regions. The overall uncertainty is likely to be higher than the range reported here
because of uncertainty in the biomass recovery under changing ambient conditions,
including atmospheric CO2 concentration, nutrients availability and climate.
. Appears in Nature Reports Climate Change | Vol 3 | May 2009.
Shevliakova, E., R. J. Stouffer, L. T. Sentman, S. W. Pacala, M. J. Spelman, S. Malyshev, 2009: Uncertainty in the land-carbon uptake due to CO2 fertilization under climate change. In prep.
Malyshev, S., E. Shevliakova, S. W. Pacala, P. C. D Milly, L. T. Sentman, K. A. Dunne, 2009: Impacts of the new land surface and vegetation dynamics model LM3V on the GFDL AGCM simulation of climate. In prep.
