Project Funding: 2011 - 2014

NRA: 2009 NASA: The Science of Terra and Aqua   

Funded by NASA

Abstract:
The net ecosystem exchange (NEE) of CO2 with the atmosphere is a fundamental measure of the balance between carbon uptake by vegetation gross primary production (GPP) and carbon loss through autotrophic and heterotrophic respiration, collectively termed ecosystem respiration (Reco). We propose to develop a continuous, integrated global record of NEE and component carbon fluxes (GPP and Reco), and associated soil temperature and moisture constraints on these fluxes. We will accomplish these objectives by fusing synergistic satellite microwave and optical-IR remote sensing information from AMSR-E and MODIS within a terrestrial carbon model framework, where MODIS provides critical information on GPP and autotrophic respiration, while AMSR-E is used to characterize surface (<10cm depth) soil moisture and temperature conditions, which are primary environmental constraints to soil heterotrophic respiration. We will apply a land surface model (LSM) assimilation scheme to mitigate atmosphere and vegetation biomass constraints to the AMSR-E retrievals and produce contiguous and continuous environmental records of these parameters for the entire terrestrial biosphere. The model assimilation process will ensure superior accuracy above AMSR-E or LSM approaches alone and will provide a means for assessing the value of AMSR-E inputs for improving LSM accuracy. These data will be used with MODIS GPP, land cover and disturbance time series to map and analyze spatial patterns, temporal anomalies and recent trends in NEE and the biophysical drivers of these fluxes. Sensitivity studies will be conducted to assess spatial scale effects and disturbance, land cover and land use change impacts to the NEE calculations. In our previous EOS science team efforts, we successfully developed a terrestrial carbon flux (TCF) model utilizing MODIS and AMSR-E inputs to quantify NEE and component carbon fluxes on a daily basis. We also developed a supporting set of AMSR-E algorithms and global retrievals for surface temperature, vegetation optical depth, freeze/thaw state dynamics and soil moisture. The TCF algorithms and remote sensing inputs are robust and have been verified using biophysical measurements from regional station networks and relatively fine scale remote sensing. We will extend this activity to a global domain, developing an integrated, long-term (10+ yr) record of NEE and component carbon fluxes and underlying moisture and temperature controls with well defined accuracy. We will apply these new data records to assess the impact of recent global warming and environmental changes to terrestrial source/sink activity for atmospheric CO2. We will also assess whether satellite optical-IR and microwave remote sensing from MODIS and AMSR-E can be used to map NEE and associated moisture and temperature constraints with sufficient accuracy to resolve spatial patterns, seasonal to annual variability and recent trends in terrestrial source/sink activity consistent with tower eddy covariance measurement based approaches. The proposed research is directly responsive to NASA SMD and Earth Science Research questions and objectives, and NASA NRC Decadal Survey carbon cycle science objectives for reducing uncertainty about the “missing sink� on land for atmospheric CO2. This research will also span the gap between EOS era carbon products and similar prodplanned under the SMAP Decadal Survey mission (projected 2014 launch). This research will contribute to better understanding and monitoring of terrestrial ecosystem functioning and carbon cycle dynamics and contribute to US Global Change Research Program (GCRP) goals for better quantification and understanding of environmental forcings and drivers of ecosystem variability, and ecosystem sensitivity and response to climate change.

Publications:

Zhang, K., Kimball, J. S., Nemani, R. R., Running, S. W., Hong, Y., Gourley, J. J., Yu, Z. 2015. Vegetation Greening and Climate Change Promote Multidecadal Rises of Global Land Evapotranspiration. Scientific Reports. 5(1). DOI: 10.1038/srep15956

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Monitoring Surface Water Changes across North American Arctic-Boreal Regions and Associated Impacts on Regional Carbon Fluxes   --   (Jennifer Dawn Watts, John S Kimball, Jinyang Du)   [abstract]   [poster]

2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• Satellite Microwave Detection of Boreal Forest Recovery from Large-Scale Wildfires   --   (Matthew O. Jones, John S Kimball, Lucas A Jones, Kyle McDonald)   [abstract]   [poster]

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Satellite Based Assessment of Net Ecosystem CO2 Exchange under the Soil Moisture Active Passive Mission   --   (John S Kimball, Yonghong Yi, Lucas A Jones, Rolf Reichle, Kyle McDonald)   [abstract]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile