Atmospheric carbon and land-atmosphere interactions research

 

Authors

Margaret S. Torn — Lawrence Berkeley National Laboratory
Ian N. Williams — Lawrence Berkeley National Laboratory
Daniel Feldman — Lawrence Berkeley National Laboratory
Sebastien Christophe Biraud — Lawrence Berkeley National Laboratory
William Riley — Lawrence Berkeley National Laboratory
Marc L. Fischer — Lawrence Berkeley National Laboratory
Dave Billesbach — University of Nebraska–Lincoln
William D. Collins — Lawrence Berkeley National Laboratory

Category

Atmospheric State & Surface

Description

Carbon and water cycles are tightly coupled in terrestrial ecosystems, giving rise to ecosystem-atmosphere feedbacks that affect surface energy forcing, clouds, and atmospheric CO2 concentrations. Understanding ecosystem influences on atmospheric conditions and CO2 concentrations, and accurately representing the effects of CO2 concentrations on radiative forcing, are critical to predicting climate change due to anthropogenic CO2 emissions and land use change. The main goal of the ASR research on atmospheric carbon at Lawrence Berkeley National Laboratory is to better understand ecosystem-climate interactions, and especially those mediated by carbon, water, and energy exchanges. This work bridges spatial scales from the plot to the region, using a combination of measurements and models. We apply observations, models, multiple tracers, and DOE facilities (primarily the ARM Climate Research Facility at the Southern Great Plains [SGP]) to:
  1. Quantify regional CO2 sources, sinks, and concentrations in SGP. We are producing a coordinated suite of carbon cycle measurements to support scaling and integration exercises in the SGP, sensor validation, and improvements to land-surface models. In addition, this project is closely coordinated with the ARM Airborne Carbon Experiment that is making weekly airborne observations of CO2 and other trace gases. We are also investing in new high risk, high payoff capabilities like (1) the “aircore” for whole column greenhouse gas sampling and (2) carbonyl sulfide as a tracer for gross primary productivity (supported jointly by the ASR and Terrestrial Ecosystem Science programs).
  2. Improve model characterization of ecosystem-atmosphere interactions, including the influences of clouds and drought on carbon cycling and feedbacks to atmosphere. To produce better land-surface forcing, we have developed a modeling framework to ingest Mesonet climate forcing, U.S. Department of Agriculture crop and vegetation cover at 30 m, and 1-m U.S. Geological Survey soil characterization data into CLM4.5 (the land model integrated in the DOE-National Center for Climate Research [NCAR] Community Earth System Model). To investigate the effects of clouds and aerosols, we performed cross-spectral analyses of surface CO2 fluxes, latent heat fluxes, and diffuse-direct radiation fraction at daily-seasonal timescales.
  3. Improve prediction of CO2 effects on radiation and temperature, based on measurement-model comparisons of long-term spectral and infrared radiation trends at SGP.