29th Conference on Agricultural and Forest Meteorology

P1.6

Seasonal dynamics of the thermodynamic entropy budget for a heterogeneous grassland

Cassandra J. Wilson, University of Kansas, Lawrence, KS; and N. A. Brunsell

It has been proven that natural events as well as human impacts have caused Earth's climate to change. Some of these changes in the Earth system can be understood by examining the physical processes that connect the atmosphere with the biosphere. Understanding this coupling is important in regards to assess how heterogeneous environments will respond to climate change. Thermodynamic entropy can be used to do this by measuring how far from local thermodynamic equilibrium a system is. We are then posed with the question, what are the seasonal dynamics of the thermodynamic entropy budget for a heterogeneous grassland environment? By comparing the seasonal variation in entropy as well as the entropy contributed through different mass (carbon and water) and heat fluxes we can start to understand how surface heterogeneity and different biomes may alter the response to global climate change. By examining the relative partitioning of entropy into latent heat and sensible heat contributions we can relate the seasonal heat variation as well as the seasonal mass variation to driving environmental factors (e.g. soil moisture etc.). With this we are left with two hypotheses. Hypothesis 1: When the surface is most heterogeneous in terms of vegetation and soil moisture (summer), we should see the highest rates of entropy flux. Hypothesis 2: We should see the component fluxes responding to both seasonal patterns of solar radiation as well as the surface moisture and vegetation. We will present results from three years of data (2006-2009) of eddy-covariance data collected at the Nelson Environmental Study Area (NESA). NESA is located in northeastern Kansas near the Lawrence Municipal Airport. Ultimately by understanding the component entropies associated with mass and energy fluxes at the tower scale we hope to be able to quantify how the local regions will likely respond to global climate change.

Poster Session 1, Poster Session
Monday, 2 August 2010, 6:00 PM-8:00 PM, Castle Peak Ballroom

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