Carbon, Water, and Energy Exchange
![[Photo:] landscape view of Howland Forest with FLUX tower.](../../local-resources/images/Howland_200.jpg)
Atmospheric studies based on flask samples of ambient air samples and models suggest that terrestrial ecosystems between 30°N and 65°N, are major sinks for anthropogenically produced CO2, removing from the atmosphere the equivalent of up to 40% of fossil fuel carbon emissions. However, uptake in this latitudinal band can vary strongly on a short-term basis. Our micrometeorological research towers in various forests, disturbed and undisturbed, have allowed us to measure whole ecosystem carbon dioxide, water vapor and energy exchange between the vegetation and the atmosphere on an almost continuous and long-term basis. Studies have demonstrated variation in annual net ecosystem C exchange (NEE), but it has been difficult to attribute this to variation in climatic factors. Ecosystem response to the environment is complex; annual carbon exchange depends upon the integrals of both photosynthetic uptake and respiratory loss. Differences in the integration period (season length), interannual variation in the factors that affect photosynthesis and respiration (e.g. light, temperature, and water availability), and variation in the biological responses to these environmental factors all contribute to differences in NEE. Our many years of tower measurement data combined with other supporting data, such as tree cores, FIA data and respiration chamber measurements have helped to develop a better understanding of how the climate system affects ecosystem processes such as these.
Selected Research Studies
- Atmospheric Exchange
- Data Assimilation
- Modeling
- Sampling
Collaborative Organizations
Last Modified: 06/28/2010
![[image:] First page of publication](/units/climate/local-resources/images/cover_nrs_2007_richardson_001.gif)
Environmental variation is directly responsible for short- but not long-term variation in forest-atmosphere carbon exchange