ESRL Helps Evaluate New Laser Technique for Remote Measurement of CO2


November 13, 2007

Researchers at BAO in Erie, CO
Graham Allan and Emily Wilson standing next to laser reflector mounted on instrument carriage.
NASA CO2 Laser at Erie High School
NASA Electronics van with BAO tower in background.

Scientists from across NOAA's Earth System Research Laboratory (ESRL) are working with NASA to evaluate a new laser technique for the remote measurement of tropospheric CO2 concentrations from space. On November 9, 2007 a team from NASA-Goddard brought their CO2 laser to ESRL's Boulder Atmospheric Observatory (BAO) in Erie, CO for an intensive week-long field study. The laser will be set-up at the Erie High School and pointed at a reflector placed at the top of the BAO tower. This prototype CO2 sensor uses robust laser technology developed by the telecommunications industry. Measurements from the NASA sensor will be compared to continuous CO2 measurements from three heights on the BAO tower that are part of ESRL Global Monitoring Division's Tall Tower CO2 monitoring program. ESRL's Chemical Science Division is also contributing to the experiment by putting one of their aircraft CO2 systems on the BAO's profiling instrument carriage.

Background:
The BAO tower has been operated by the ESRL Physical Sciences Division since the mid-1970s and serves as a unique facility for monitoring the Earth's atmospheric boundary layer. The 300 m tower at the BAO is equipped with sensors that continuously monitor CO2 from 3 levels on the tower, and an instrument carriage that carries an additional sensor up and down the tower to acquire complete vertical profiles of CO2.

The NASA Orbiting Carbon Observatory (OCO) is the first space mission focused on atmospheric CO2 for measuring total column CO2 and O2 by measuring the spectral absorption in reflected sunlight. The recent Decadal Survey for Earth Science by the US National Research Council has recommended a subsequent laser-based CO2 measuring mission called ASCENDS.

Significance:
Accurate measurements of tropospheric CO2 abundances with global-coverage and monthly temporal resolution are needed to quantify processes that regulate CO2 exchange with the land and oceans. This short but intensive one-week experiment will provide valuable data for advancing the design of laser-based instrumentation for measurements of CO2 from space. This activity supports NOAA's mission goal of understanding climate variability and change to enhance society's ability to plan and respond.

Contact: Dan Wolfe