The researchers calculated land surface variability metrics and land-atmosphere coupling metrics for the Community Earth System Model (CESM1) and Community Atmosphere Model (CAM5) using data from the Last Millennium Ensemble (LME) to assess spatial and seasonal variability of land-atmosphere feedbacks in the models and how they change in past climate scenarios. They hypothesize that land use practices will impact the rate of climate change, extremes, and predictability. The ensemble data was used to quantify uncertainty in coupling metric calculations, which have typically been estimated from single long simulations or short ensembles. Comparison to metrics calculated from remote sensing data will provide understanding of real-world mechanisms.

1. Materials and methods:
We calculated a suite of land surface variability (Latent and
Sensible Heat, along with Soil Water in 10CM depth) and
land-atmosphere coupling metrics (Two-Legged Coupling
Metrics) for “The Community Earth System Model” CESM1,
and “The Community Atmosphere Model” (CAM5) to assess
the spatial and seasonal variability of land-atmosphere
feedbacks in the model, and how they change in past climate
scenarios via “LME”. Last Millennium community
experiments, referred to as the Last Millennium Ensemble
(LME). “Ensemble members extend from 850 to 2006 using
reconstructions for the transient evolution of solar intensity,
volcanic emissions, greenhouse gases, aerosols, land use
conditions, and orbital parameters, together and individually.”
We used the ensemble data to quantify the uncertainty in the
calculation of these coupling metrics, which have historically
been estimated from long single simulations or ensembles of
short (1-year or shorter) hind casts.
The researchers hypothesize that the rate of climate change,
frequency and severity of extremes, and predictability of
climate variations will depend on the type of regional land use
practices implemented in the coming decades. While the study
of land use land cover change (LULCC) impacts on climate
are not new, this project is starting from a point where the
model consensus is that there will be a strengthened coupling
between land and atmosphere in a warming climate.
Results
We calculated a suite of land surface variability
(Latent and Sensible Heat, along with Soil Water in
10CM depth) and land-atmosphere coupling metrics
(Two-Legged Coupling Metrics) for “The Community
Earth System Model” CESM1, and “The Community
Atmosphere Model” (CAM5) to assess the spatial and
seasonal variability of land-atmosphere feedbacks in
the model, and how they change in past climate
scenarios via “LME”. Last Millennium community
experiments, referred to as the Last Millennium
Ensemble (LME). “Ensemble members extend from
850 to 2006 using reconstructions for the transient
evolution of solar intensity, volcanic emissions,
greenhouse gases, aerosols, land use conditions, and
orbital parameters, together and individually.”
Conclusions
We used the ensemble data to quantify the
uncertainty in the calculation of these coupling metrics,
which have historically been estimated from long single
simulations or ensembles of short (1-year or shorter)
hind casts. Comparison to metrics calculated from
remotely sensed data (R.S) with these model outputs
will give us a better understanding of the real world
mechanism.
Confronting Satellite with Climate Models
Measuring Coupling Between Land and Atmosphere
Ako Heidari, Paul Dirmeyer
Department of Geography and Geo-information Science, George Mason University
Literature cited
 Otto-Bliesner, B.L., E.C. Brady, J. Fasullo, A. Jahn, L. Landrum, S. Stevenson, N.
Rosenbloom, A. Mai, G. Strand. Climate Variability and Change since 850 C.E.: An
Ensemble Approach with the Community Earth System Model (CESM), Bulletin of
the American Meteorological Society, 735-754 (May 2016 issue)
Introduction
Changes in land use and land cover, such as converting forests to
cropland or irrigating formerly dry areas, are known to impact climate
on the local and regional level. There is some indication from prior
modeling studies that the land-atmosphere interactions that cause these
climate impacts will become more pronounced in a warming world. In
order to further study this concept, researchers will perform simulations
using advanced numerical models and compare those results to
observational data to assess how the models are performing.
Fig. 3 Comparing the Impact of Land Use Land Cover Change on the Coupling between
Land and Atmosphere vs. Control Run, 10th
& 20th
Century.
Fig. 1 Terrestrial and Atmospheric Fluxes:
1)Soil Water in 10CM Depth 2)Latent Heat Flux 3)Sensible Heat Flux
Fig. 2Comparing the effect of Control Run vs. one single force
1)10th
Century, Impact of Control Run minus Land Use Land Cover Change
2)20th
Century, Same Comparison
3)Same Century, Different Comparison: Impact of Control Run minus Green House Gas
Fig. 3Comparing the effect of All Forces vs. one single force
1)10th
Century, Impact of All Forces minus Land Use Land Cover Change
2)15th
Century, Same Comparison
3)18th
Century, Same Comparison
4)19th
Century, Same Comparison
5)Same Century, Different Comparison: Latent Heat Coupling rather than Sensible
Heat