George Washington University and Mesa Photonics have developed a Laser Heterodyne Radiometer (LHR) that simultaneously measures CO2, CH4, H2O, and O2 mixing ratios throughout the troposphere and lower stratosphere. Welcome to a seminar to learn more about this.

George Washington University and Mesa Photonics have developed a Laser Heterodyne Radiometer (LHR) that simultaneously measures CO₂, CH₄, H₂O, and O₂ mixing ratios throughout the troposphere and lower stratosphere. One of the prototype instruments is housed in an observatory installed at the Global Change Environmental wetland (GCREW) at the Smithsonian Environmental Research Center (SERC) near Edgewater, Maryland. The sea level marsh at GCREW is adjacent to a mature secondary upland forest and is also influenced by emissions from the dense population centers within the northeast US megalopolis. The data record from this instrument is anticipated to not only be complementary to other co-located surface concentration and flux measurements but is also expected to be useful in determining transport and land-air surface exchange rates at larger scales.

In this presentation, we will review the instrument design and present measurements from both sites collected throughout the 2023 calendar year. Two spectral regions will be emphasized: ~1650 nm for quantification of methane and carbon dioxide mixing ratios and ~1278 nm for refined vertical profiling of temperature using fitting of several molecular oxygen transitions. A challenge in this deployment has been in processing and interpreting the vast amount of raw data produced. After an introduction to the technology, the presentation will focus on our retrieval algorithm as well as a sensitivity analysis to establish measurement uncertainty.

We are currently exploring other use cases for the LHR technology through the detection and characterization of wildfires and industrial flares. We are building sensor platforms for laboratory demonstrations as well as simple “field-scale” demonstrations here referred to as Fire Optical Metrology, or FOM. The seminar will briefly introduce this technology and our project goals.

Fika will be served from 15.15, and the seminar starts at 15.30.

Welcome to join!