Vertical column dual-comb spectroscopy to a TBS

16 September 2024 - 27 September 2024

Lead Scientist: Peter Schwindt

Observatory: sgp

Greenhouse gases (GHGs) are key contributors to climate change and there is a critical need for the ability to detect, quantify, and attribute sources and sinks of GHGs with high temporal and spatial resolution. Current methods are typically based on continuously operating near-surface point sensors or intermittent aerial/satellite observations. Dual optical-frequency comb spectroscopy (“dual-comb spectroscopy”, DCS) is a laser-based technique that can bridge this sensing gap by providing high-precision, high-accuracy, and high-temporal-resolution detection and quantification of trace gases over kilometer-length scales, connecting localized and regional observations. A single DCS system can also provide spatial resolution for source/sink attribution with the addition of a few minor optical elements, enabling cross-validation of other observations (e.g., TCCON, OCO-2/3, GOSAT-1/2).


Currently, the majority of DCS demonstrations have been performed in the horizontal near the ground. Combining DCS with Atmospheric Radiation Measurement’s (ARM’s) tethered balloon system (TBS) will enable DCS’s strengths to be applied along the vertical direction. We propose the first vertical DCS measurements that last several hours and reach across the atmospheric boundary layer. Development of vertical DCS could enable continuous, high-precision, high-temporal-resolution capabilities for atmospheric profiling, quantification of GHG concentrations within the troposphere, and boundary-layer studies, and be fed into atmospheric models. This proof-of-concept demonstration of DCS coupled to a TBS could lead to future ground-to-stratospheric balloon or satellite vertical column studies.


Roger Ding