Research

Current BEACHON Research Activities


Russ Monson (Univ. of Arizona) studies how climate change is influencing the carbon and water cycles in the forests at Manitou. See a short video that below that describes this work. This is actually an excellent overview of many of the BEACHON projects.


The Terpene Project from Lost Nomad Media on Vimeo.

Jim Smith and John Ortega (ACD) have been performing measurements of the aerosol size distribution at MEF continuously since 2008. The goals of these measurements include understanding new particle formation in a biogenically-dominated site and to understand the possible role of urban emissions at the site. Numerous guest aerosol measurements that have happened at MEF recently include a year-long record of Cloud Condensation Nuclei (CCN) concentrations (collaborating with Sonia Kreidenweis, CSU) and measurements of primary biological particles (collaborating with Alex Huffmann, DU).

Saewung Kim (ACD, now at UC Irvine) performs measurements at MEF to better understand how the tropospheric oxidation capacity is determined by biosphere-atmosphere-human interactions. The outcomes of intensive field measurements with a comprehensive measurement suite will serve basis for better predictions in fast changing regional and global air quality.

Peter Harley's (ACD) BEACHON research conducted at MEF and elsewhere focuses on the physical and biological factors that control emissions of biogenic volatile organic compounds from vegetation. Using leaf or branch enclosure systems, coupled with either Gas Chromatography-Mass Spectrometry or Proton-Transfer Reaction Mass Spectrometry, he seeks to identify the major organic compounds being emitted from different plant species, and to characterize the instantaneous effects of incident light and leaf temperature on emissions, as well as the longer term effects of drought, pollution, herbivory or other stresses. This information is critical to those attempting to model the role of forest emissions on tropospheric chemistry and secondary aerosol production.

Jim Greenberg (ACD) has recently submitted a manuscript for publication with the following abstract: Biogenic volatile organic compound (BVOC) emissions come from a variety of sources, including living above ground foliar biomass and microbial decomposition of dead organic matter at the soil surface (litter and soil organic matter). There are, however, few reports that quantify the contributions of each component. Measurements of emissions fluxes are now made above the vegetation canopy, but these include contributions from all sources. BVOC emission models currently include detailed parameterization of the emissions from foliar biomass but do not have an equally descriptive treatment of emissions from litter or other sources. We present here results of laboratory and field experiments to characterize the major parameters that control emissions from litter. For a given type of litter, an exponential dependence on temperature is the most important variable in predicting emissions. The moisture content of the litter plays a minor role, except during and immediately following rain events. The percentage of carbon readily available for microbial and other decomposition processes decreases with litter age. These 3 variables are combined in a model to explain over 50% of the variance of individual BVOC emission fluxes measured. The modeled results of litter emissions were compared with above canopy fluxes. Litter emissions constituted less than 1% of above canopy emissions for all BVOCs measured. A comparison of terpene oil pools in litter and live needles with above-canopy fluxes suggests that there may be another canopy terpene source in addition to needle storage or that some terpene emissions may be light-dependent. Ground enclosure measurements indicated compensation point concentrations of BVOCs (equilibrium between BVOC emission and deposition) after approximately 10 minutes, suggesting that previously reported static enclosure measurements may have underestimated litter emissions.

Ethan Gutmann (ASP) is using an advanced GPS unit located at Manitou to assess the limitations imposed by the surrounding trees on snow and soil moisture measurements made from the noise in the GPS system. (I can provide references for the technique if you are interested but have not published anything from the Manitou data yet). His second project is more hydrologic in nature, but so far has not progressed much yet: Ethan Gutmann is analyzing the effect of soil hydraulic properties on water availability and thus evapotranspiration at Manitou. In particular, Gutmann is studying how the effective landscape hydraulic properties differ from the small scale properties.

Thomas Karl (ACD) will perform PTR-TOF-MS flux measurements at the Manitou research station in late June/early July 2012. Measurements will target a quantitative assessment of the relative contribution of isoprene and 232 MBO fluxes.

Andrew Turnipseed (ACD) performs continuous measurements at MEF of meteorological variables (Wind speed/direction, temperature, humidity, etc.), ecosystem level exchanges (fluxes) of energy, water and CO2 and concentrations of key trace gases (ozone, SO2, NOx, etc.). These measurements have been ongoing since August, 2008. These measurements have provided insight for campaign planning and have also supported all of the major field campaigns that we have organized (BEACHON-SRM, BEACHON-ROCS and BEACHON-ROMBAS). They also have supported longer-term seasonal studies concerning water and carbon cycling which have involved several university and NCAR collaborators. He has also been involved in logistical planning for all of the major field campaigns at the Manitou Forest Observatory. A list of the available data/measurements can be found in Table 1 and a diagram of the sensor locations on the chemistry tower is shown in Figure 1.

Other BEACHON-related activities include the implementation of GLOBOENET (Global Organic Emissions Network) where Turnipseed and colleagues are installing several simple, low-cost, low power sampling systems at sites around the world to determine fluxes of biogenic VOC within major biomes. These measurements are based on the technique of Relaxed Eddy Accumulation and the sampling systems were designed by he and Steve Shertz (ACD). Collaborators on site are trained and take measurements approximately weekly to bi-weekly. Currently, they have 7 of these REA samplers in operation and are progressing towards the next version. Since the project was initiated in 2006, they have measured VOC fluxes from 14 different sites covering nearly 66 months of time. Near-future plans include installing/operating two of these REAs within tropical forests in Brazil along with samplers in Israel and Europe.

Updated 25 October 2012.

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ACOM | Atmospheric Chemistry Observations & Modeling