Lori Thompson Sentman

Developing and using comprehensive climate and biosphere models of the atmosphere-ocean-ice-land system, Earth System Models (ESMs), to identify and elucidate physical, biogeochemical and ecological mechanisms, assess 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 interests include:

• impact of land use change on the terrestrial biosphere carbon stores and fluxes
• biosphysical effects of land use change on climate
  
• impact of volcanic activity on the terrestrial biosphere carbon cycle, and the associated feedbacks and interactions with climate
• sensitivity of CO2 fertilization on climate
• evaluation of the role of secondary vegetation on the terrestrial carbon cycle
  
• impact of paleoclimate events on the various modes of climate variability (i.e., ENSO, AMOC) and the global carbon cycle to better understand and predict future climate change
  
• Execution, analysis and data publishing of GFDL's Earth System Models for the Coupled Model Intercomparison Project Phase 5 (CMIP5)
  

• Dunne, John P., Jasmin John, Elena Shevliakova, Ronald J Stouffer, John P Krasting, Sergey Malyshev, P C D Milly, Lori T Sentman, Alistair Adcroft, W F Cooke, Krista A Dunne, Stephen M Griffies, Robert W Hallberg, Matthew J Harrison, Hiram Levy II, Andrew T Wittenberg, Peter Phillipps, and N Zadeh, in press: GFDL’s ESM2 global coupled climate-carbon Earth System Models Part II: Carbon system formulation and baseline simulation characteristics. Journal of Climate. DOI:10.1175/JCLI-D-12-00150.1. 10/12.
• Dunne, John P., Jasmin John, Alistair Adcroft, Stephen M Griffies, Robert W Hallberg, Elena Shevliakova, Ronald J Stouffer, W F Cooke, Krista A Dunne, Matthew J Harrison, John P Krasting, Sergey Malyshev, P C D Milly, Peter Phillipps, Lori T Sentman, Bonita L Samuels, Michael J Spelman, Michael Winton, Andrew T Wittenberg, and N Zadeh, October 2012: GFDL's ESM2 global coupled climate-carbon Earth System Models Part I: Physical formulation and baseline simulation characteristics. Journal of Climate, 25(19), DOI:10.1175/JCLI-D-11-00560.1.
• Sentman, Lori T., Elena Shevliakova, Ronald J Stouffer, and Sergey Malyshev, October 2011: Time scales of terrestrial carbon response related to land-use application: Implications for initializing an earth system model. Earth Interactions, 15(30), DOI:10.1175/2011EI401.1.
  
• Shevliakova, Elena, S W Pacala, Sergey Malyshev, P C D Milly, and Lori T Sentman, et al., June 2009: Carbon cycling under 300 years of land use change: Importance of the secondary vegetation sink. Global Biogeochemical Cycles, 23, GB2022, DOI:10.1029/2007GB003176. [ Abstract PDF].

• Anderson, Jeffrey L., Ventakramani Balaji, Anthony J Broccoli, W F Cooke, Thomas L Delworth, Keith W Dixon, Leo J Donner, Krista A Dunne, Stuart Freidenreich, Stephen T Garner, Rich Gudgel, C Tony Gordon, Isaac M Held, Richard S Hemler, Larry W Horowitz, Stephen A Klein, Thomas R Knutson, P J Kushner, Amy R Langenhorst, Ngar-Cheung Lau, Z Liang, Sergey Malyshev, P C D Milly, Mary Jo Nath, Jeff J Ploshay, V Ramaswamy, M Daniel Schwarzkopf, Elena Shevliakova, Joseph J Sirutis, Brian J Soden, William F Stern, Lori T Sentman, R John Wilson, Andrew T Wittenberg, and Bruce Wyman, December 2004: The New GFDL global atmosphere and land model AM2–LM2: Evaluation with prescribed SST simulations. Journal of Climate, 17(24), 4641-4673.

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.