Research Programs

Britt Stephens - EOL & TIIMES
FY2006 activities

TIIMES Theme:
BGS & BEACHON

Compiled by Britton Stephens - EOL - TIIMES

Collaborators: Sherri Heck (CU)

Carbon in the Mountains Experiment

Composite of the NSF/NCAR C-130 research aircraft flying over the Rocky Mountains near Boulder. (Photo by Carlye Calvin.)

NCAR continues to make significant contributions towards advancing our understanding of global biogeochemical cycling and supporting the biogeosciences research community. A strong focus has been on carbon exchange in Western forests through the Carbon in the Mountains Experiment, where efforts to process and analyze data from ’04 Airborne Carbon in the Mountains Experiment (ACME ‘04) and ground-based intensive campaigns have revealed insights into the critical roles spring-time interactions with the water cycle play in the annual carbon balance of these ecosystems. Work in the past year has also included planning for a second intensive campaign in 2007 and an expansion of the in situ CO₂ observing network as a key contribution to the multi-agency North American Carbon Program (NACP).

NCAR is collaborating with investigators at CU, CSU, and University of Virginia to plan and conduct the ACME ’07 campaign on the University of Wyoming King Air.  This campaign will be the second Airborne Carbon in the Mountains Campaign, focusing on Colorado and Wyoming, and will include flights from early spring through fall.  The payload will include the RAF community oxygen instrument to be completed this fall.

Rocky RACCOON

FEF - Fraser Experimental Forest HDP - Hidden Peak NWR - Niwot Ridge SPL - Storm Peak Laboratory Map showing existing Rocky RACCOON sites (purple arrows) and planned and potential new sites (red circles) as of September, 2006.

The Regional Atmospheric Continuous CO₂ Network in the Rocky Mountains (Rocky RACCOON) presently consists of four sites installed in fall of 2005 and spring of 2006:  Niwot Ridge, near Ward, Colorado; Storm Peak Laboratory (SPL) near Steamboat Springs, Colorado; Fraser Experimental Forest (FEF), near Fraser Colorado; and Hidden Peak (HDP), near Snowbird, Utah.  These measurements support the national-scale carbon budgeting of NACP and provide independent information on local to regional scale respiration and photosynthesis rates in the Rockies.

This project uses the NCAR-developed Autonomous Inexpensive Robust CO₂ Analyzer (AIRCOA).  These units measure CO₂ concentrations at 3 levels on a tower, producing individual measurements every 2.5 minutes precise to 0.1 ppm CO₂ and closely tied to the WMO CO₂ scale.  A key component in the robustness of these analyzers is near real-time data processing with extensive automated diagnostic tests to verify normal operation and make new results available from a web interface every day.  The success of the AIRCOA units has generated considerable outside interest and we have shared the design with and trained university (Penn State, Oregon State, Stanford) collaborators installing similar systems around the U.S., and are collaborating with member institutions of the CarboEurope project to deploy AIRCOA sensors at 5 sites in Europe. 

We will add two additional Rocky RACCOON sites in the coming year in further support of NACP and will collaborate with Penn State, CSU, OSU, and other institutions to formalize a national CO₂ observing network and pursue improvements in inter-site comparability and data management.  We will perform analysis of and write papers based on RACCOON data, focusing on local to regional scale carbon budgeting.

Community Airborn Oxygen Instrument Development

HIAPER Pole-to-Pole Observations (HIPPO) flight path

NCAR is also playing a leadership role in instrument development for the biogeosciences.  With support from the Director’s office, EOL-TIIMES has begun fabrication of a Community Airborne Oxygen Instrument based on a vacuum-ultraviolet absorption technique.  Because of the unique relationships between industrial, terrestrial, and oceanic exchange of carbon and oxygen, this instrument promises valuable insights into these processes. In FY07 we will complete fabrication and testing of the Community Airborne Oxygen Instrument and continue pursuing collaborations for its use on NSF aircraft.

We have completed upgrades to and certification of the MEDUSA (Multiple Enclosure Device for Unfractionated Sampling of Air) flask sampler in anticipation of participation in the Brazilian-Amazonia Regional Carbon Airborne (BARCA) study scheduled for January 2007, as well as in future studies on the C130 and GV aircraft. The four week BARCA Campaign will utlize the Brazilian Lear Jet flying over the Amazon. During BARCA we will collect flasks using the MEDUSA sampler and analyze the measurements made on these flasks at Scripps, NOAA GMD, and CU INSTAAR.

The airborne oxygen instrument and MEDUSA are being included as primary instruments in the plans for the HIAPER Pole-to-Pole Observations (HIPPO ’08-‘10) project.  This ambitious campaign to use the GV aircraft to conduct a global seasonal survey of atmospheric tracers important for carbon cycling and atmospheric chemistry is a collaboration between Harvard, NCAR, Scripps, and NOAA.

Oxygen & Carbon Dioxide Calibration, Profiles, & Measurements

Midday vertical CO2 profiles measured at 12 global locations averaged over different seasonal intervals. Summer profiles (A) are averages over the months July – September, annual-mean profiles (B) are averages over all months, and winter/spring profiles (C) are averages over the months January – May. Thick gray lines in each panel represent Northern Hemisphere average profiles for the same times.

The NCAR O₂ / CO₂ Calibration Facility at RAF continues to support these efforts and RAF chemistry measurements by providing reference gases tied to internationally recognized calibration scales.  We have participated in two international round-robin cylinder comparison exercises in the past year, WMO (CO₂) and GOLLUM (O₂).  Preliminary results show that our calibration system is performing very well in comparison to other participating laboratories.  These instruments have also supported the work of two international visitors to NCAR.

We have completed an analysis of light-aircraft vertical CO₂ profiles measured at twelve global sites by six international laboratories.  The results suggest a significant revision to the consensus view of the global carbon cycle by revealing systematic biases in atmospheric models that predict large northern terrestrial CO₂ uptake and large tropical CO₂ releases.

With support from EOL and the Director’s office, we have initiated and will continue a project in collaboration with CU (graduate student Sherri Heck) to install AIRCOA units for CO₂ measurements on the Navajo Reservation and in Africa, to provide carbon cycle insights, and to provide a basis for local education and capacity building.