Prof. Paul Dirmeyer
Building: Research Hall
Office: Room 266
Mail stop: 6C5
Phone: +1-703-993-5363
E-mail: pdirmeyegmu.edu

 

NSF AGS-1419445

EaSM-3: Land Use Change and Land Atmosphere Feedback Processes as Regulators of Regional Climate Change 2014-2018

P.I.: Paul A. Dirmeyer (GMU)
Co-PIs: David Lawrence and Richard Neale (NCAR)
Post-Doc Fellow: Liang Chen

Program:
Decadal and Regional Climate Prediction using Earth System Models (EaSM)

Project Summary:
Overview:
The proposed work will explore how regional changes in land use over the coming decades could alter land-atmosphere interactions against the backdrop of a warming climate. It is posited that regions of strong land-atmosphere feedback in the physical climate system will evolve and migrate significantly in a changing climate. The rate of climate change, frequency and severity of extremes, and predictability of climate variations are hypothesized to depend on the type of regional land use practices implemented in the coming decades.
To determine the effects of land use changes such as agricultural expansion, relocation, irrigation, and other land use practices on regional climate change, variability, and predictability, a plan is proposed to examine the coupled feedback processes between land and atmosphere in the Community Earth System Model (CESM). This includes examination of important climate processes over land within observational data and models to quantify (1) the relationships between soil moisture, vegetation, and surface fluxes; (2) the connection between surface fluxes and the development of the atmospheric boundary layer, clouds and precipitation; (3) the role of the biogeophysical elements in these processes. A recently implemented crop sub-model in CESM will allow for much more realistic simulation of agriculture than previously possible in this climate model.
Intellectual Merit:
This proposal directly addresses the emerging need to understand and quantify the nature of land-atmosphere interactions as they exist today, as they may be modulated by the radiatively-driven component of climate change, and as they may evolve with changing land use. The proposed work will build upon recent advances in process-based understanding of coupling by going beyond the regions, metrics and time periods that have recently begun to be studied, and by more thoroughly exploring how anthropogenic land use can modify the physical and biospheric pathways through which land-atmosphere interactions are initiated and maintained.
This proposal investigates how sub-seasonal to seasonal variability and predictability, where land-atmosphere feedbacks have been found to be crucial, evolve across decadal time scales as a function of known, expected and possible anthropogenic changes. This proposal undertakes the call to address human processes that drive the climate system, including their pertinence to agriculture, forestry and land cover/use. The proposed work will directly identify and quantify feedback loops between land and atmosphere, and their impacts on natural and human systems. Specifically, trends and uncertainties in land use change, irrigation expansion, and other agricultural practices will be investigated in terms of their effects on these feedbacks in a changing climate. A range of observational data will be employed to validate functional relationships among states and fluxes in CESM for current climate, informing model validation and development.
Broader Impacts:
This project will advance infrastructure for Earth system research and education by providing new evaluations of the CESM modeling tool in the context of its coupled land-atmosphere behavior. Improved understanding of the potential impacts and interactions of climate and land use change provides a benefit to society by allowing for more informed policymaking, especially as land use change impacts on climate may amplify in the future. This project integrates teaching of science and math through the training of a post-doctoral research associate and a graduate student in the interdisciplinary problems of current and future climate simulation and predictability, metrics and benchmarking, statistical analysis of global and regional-scale data sets, and modeling of terrestrial and atmospheric processes. Thus, it contributes to the development of the next generation of Earth System modelers.
The knowledge and experience developed through this project will contribute to the design and implementation of future model comparisons. Co-PI Lawrence is co-leader of the Land Use Model Inter-comparison Project (LUMIP) that is being developed as a satellite-MIP of CMIP6. The work proposed here will help define metrics for assessment of land use change and land-atmosphere interactions and will contribute to the formation of hypotheses, experiments, and analyses that can be tested and conducted within LUMIP. The work will also inform research in the IGBP and GEWEX scientific communities.

Products:
Coupling Metrics Toolkit (CoMeT)

Reports:
EASM-3 PI Meeting Poster, August, 2015
Year 1 Progress Report, May, 2015
Year 2 Progress Report, May, 2016
Year 3 Progress Report, May, 2017

Publications:
#1. Chen, L. and P. A. Dirmeyer, 2016: Adapting observationally-based metrics of biogeophysical feedbacks from land cover change to climate modeling. Env. Res. Lett., 11, 034002, doi: 10.1088/1748-9326/11/3/034002.
#2. Chen, L. and O. W. Frauenfeld, 2016: Impacts of urbanization on future climate in China. Climate Dyn., 47, 345-357, doi: 10.1007/s00382-015-2840-6.
#3. Chen, L., P. A. Dirmeyer, A. Tawfik and D. M. Lawrence, 2017: Sensitivities of land cover-precipitation feedback to convective triggering. J. Hydrometeor., 18, 2265-2284, doi: 10.1175/JHM-D-17-0011.1.
#4. Chen, L. and P. A. Dirmeyer, 2017: Impacts of land use/land cover change on afternoon precipitation over North America. J. Climate, 30, 2121-2140, doi: 10.1175/JCLI-D-16-0589.1
#5. Tawfik, A. B., D. M. Lawrence, and P. A. Dirmeyer, 2017: Representing sub-grid convective initiation in the Community Earth System Model. J. Adv. Mod. Earth Sys., 9, doi: 10.1002/2016MS000866.
÷ Chen, L., P. A. Dirmeyer, Z. Guo and N. M. Schultz, 2017: Pairing FLUXNET sites to validate model representations of land use/land cover change. Hydrol. Earth Sys. Sci. Discuss., (in revision), doi: 10.5194/hess-2017-190.
÷ Dirmeyer, P. A., L. Chen, J. Wu, C.-S. Shin, B. Huang, B. Cash, M. Bosilovich, S. Mahanama, R. D. Koster, J. A. Santanello Jr., M. B. Ek, G. Balsamo, and D. M. Lawrence, 2017: Verification of land-atmosphere coupling in forecast models, reanalyses and land surface models using flux site observations. J. Hydrometeor., (in revision).