US-BFS AmeriFlux

Robert J. Bernard Biological Field Station

The Bernard Field Station (BFS), an 86-acre academic resource of the Claremont University Consortium, is situated within the campus of The Claremont Colleges in Claremont, CA. Its principal habitats comprise coastal sage scrub, Riversidian alluvial fan scrub, live oak forest, and grassland. The eddy covariance tower is located in the 'neck' of the field station, home to a protected area of Coastal Sage Scrub, dominated by Artemisia californica. BFS is within walking distance of Harvey Mudd College, serving as an invaluable outdoor laboratory resource for the students. With extensive flora and fauna, including over 170 species of birds, 27 species of mammals, and more than 700 species of insects, it embodies a significant ecological haven in the region that is otherwise Southern California suburbs.


The key analytical objectives of the Bernard Field Station site include the measurements of momentum, sensible heat, water vapour, latent heat, and CO₂ exchange between the coastal sage scrub and the atmosphere. Among the additional research topics includes: 1) investigation of the relationships of energy and mass exchanges between the atmosphere and the Coastal sage scrub as the region warms and precipitation patterns change; 2) speciated Volatile Organic Compound (VOC) measurements performed directly from plant species that makeup sage scrub community to link reactive carbon fluxes with ecosystem respiration; 3) plant physiology, particularly involving the dominant Artemisia californica within the coastal sage scrub; 4) studying long-term impact of climate change on this unique ecosystem; 5) exploring the role of sage scrub emissions on ozone chemistry.

Instruments

    • IRGASON (1.75 x canopy height) - CO₂, water vapour, sensible heat, latent heat, and momentum fluxes, 3D wind, friction velocity, stability parameters

    • CSAT3B (canopy height) - sensible heat and momentum fluxes, 3D wind, friction velocity, stability parameters

    • List to come

    • List to come

Data Access

  • Links to come.

    More data will be available on this site than what we can send to AmeriFlux.

  • Our KestrelMet 6000 provides real time (every 15 minutes) weather for the site to the Ambient Weather Netowrk.

  • Link to come

External Links

Tower History and Site Selection

The placement of this site and instrumental setup are thanks to Helen Chen, who designed our AmeriFlux site for her undergraduate thesis (Harvey Mudd College, Department of Chemistry, 2023-2024).

The site location and measurement heights were chosen so that the fetch would be in the region of native sage scrub at our field station.

Example flux data

A nearly 2-week time series is included to show an example of what data from our tower looks like thanks to Matthew Simpson who processed this flux and meteorological data. Daytime windows are highlighted to make day/night differences more apparent. We see the anticipated uptake of carbon during the day (the negative CO₂ fluxes).

Example data from the met. station

The multiplot shows a sample time series of data taken by the KestrelMet6000 weather station and 3 Watermark (IRROMETER) soil probes our group installed at the BFS.

The top panel shows measurements of air temperature and relative humidity (note that days are hot and dry) while the bottom two contour plots show soil temperature (°C) and soil moisture (cB).

Looking at time averaged soil moisture, we can see the surface layer has essentially no moisture left by late July.