A5074154582- Spectroscopy and Laser Applications
- Atmospheric and Environmental Gas Dynamics
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Advanced Fiber Laser Technologies
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Sensor Technologies
- Mercury impact and mitigation studies
- Atmospheric aerosols and clouds
- Ocean Acidification Effects and Responses
- Marine and coastal ecosystems
- Laser Design and Applications
- Air Quality Monitoring and Forecasting
- Air Quality and Health Impacts
- Methane Hydrates and Related Phenomena
- Advanced Fiber Optic Sensors
- Combustion and flame dynamics
- Analytical Chemistry and Sensors
- Meteorological Phenomena and Simulations
- Calibration and Measurement Techniques
- GaN-based semiconductor devices and materials
- Oil, Gas, and Environmental Issues
- Fire dynamics and safety research
- Fire effects on ecosystems
- Semiconductor Quantum Structures and Devices
University of Colorado Boulder
2015-2024
University of Colorado System
2020-2022
Texas A&M Health Science Center
2022
Cooperative Institute for Research in Environmental Sciences
2014-2016
Chromophoric water-soluble organic matter in atmospheric aerosols potentially plays an important role aqueous reactions and light absorption by organics. The fluorescence chemical–structural characteristics of the chromophoric submicron collected urban, forest, marine environments (Nagoya, Kii Peninsula, tropical Eastern Pacific) were investigated using excitation–emission matrices (EEMs) a high-resolution aerosol mass spectrometer. A total three types chromophores, two with similar to those...
Identification and quantification of trace-gas sources is a major challenge for understanding regulating air quality greenhouse gas emissions. Current approaches provide either continuous but localized monitoring, or quasi-instantaneous “snapshot-in-time” regional monitoring. There need emissions detection that provides both coverage, because sinks can be episodic spatially variable. We field deploy dual frequency comb laser spectrometer the first time, enabling an observing system over...
Abstract. We present the first detection of glyoxal (CHOCHO) over remote tropical Pacific Ocean in Marine Boundary Layer (MBL). The measurements were conducted by means University Colorado Ship Multi-Axis Differential Optical Absorption Spectroscopy (CU SMAX-DOAS) instrument aboard research vessel Ronald H. Brown. was on a cruise framework VAMOS Ocean-Cloud-Atmosphere-Land Study – Regional Experiment (VOCALS-REx) and Tropical Atmosphere (TAO) projects lasting from October 2008 through...
Abstract. Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone atmospheric aerosols, yet models remain largely untested for lack vertically resolved measurements bromine monoxide (BrO), iodine (IO) small oxygenated hydrocarbons like glyoxal (CHOCHO) in the troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) O2–O2 collision complexes (O4) were measured by University Colorado Airborne Multi-AXis Differential Optical Absorption...
Significance Our measurements show that tropospheric halogen chemistry has a larger capacity to destroy O 3 and oxidize atmospheric mercury than previously recognized. Halogen is currently missing in most global climate models, effective at removing altitudes where intercontinental transport occurs. It further helps explain the low levels preindustrial times. Public health concerns arise from bioaccumulation of neurotoxin fish. results emphasize bromine free troposphere oxidizes faster rate,...
Abstract. The University of Colorado Airborne Multi-Axis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument uses solar stray light to detect and quantify multiple trace gases, including nitrogen dioxide (NO2), glyoxal (CHOCHO), formaldehyde (HCHO), water vapor (H2O), nitrous acid (HONO), iodine monoxide (IO), bromine (BrO), oxygen dimers (O4) at wavelengths (absorption bands 360, 477, 577, 632 nm) simultaneously in the open atmosphere. is unique as it (1) features a...
Abstract. We present the first quantitative intercomparison between two open-path dual-comb spectroscopy (DCS) instruments which were operated across adjacent 2 km open-air paths over a 2-week period. used DCS to measure atmospheric absorption spectrum in near infrared from 6023 6376 cm−1 (1568 1660 nm), corresponding 355 bandwidth, at 0.0067 sample spacing. The measured spectra agree with each other within 5 × 10−4 absorbance without any external calibration of either instrument. are fit...
Abstract. Here we present first eddy covariance (EC) measurements of fluxes glyoxal, the smallest α-dicarbonyl product hydrocarbon oxidation, and a precursor for secondary organic aerosol (SOA). The unique physical chemical properties glyoxal – i.e., high solubility in water (effective Henry's law constant, KH = 4.2 × 105 M atm−1) short atmospheric lifetime (~2 h at solar noon) make it indicator species carbon oxidation marine atmosphere. Previous reports elevated over oceans remain...
Abstract. We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS) instrument to retrieve bromine oxide (BrO), iodine (IO), formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO2) oxygen dimer (O4) in coastal atmosphere Gulf Mexico. The detection sensitivity DOAS measurements is proportional root mean square (RMS) residual spectrum that remains after all absorbers have been subtracted. Here we describe CU...
Abstract. The growth of aerosol due to the aqueous phase oxidation sulfur dioxide by ozone was measured in laboratory-generated clouds created Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at European Organization for Nuclear Research (CERN). Experiments were performed 10 and −10 °C, on acidic (sulfuric acid) partially fully neutralised (ammonium sulfate) seed aerosol. Clouds generated performing an adiabatic expansion – pressurising 220 hPa above atmospheric pressure, then rapidly...
Dual-comb spectroscopy has demonstrated remarkable capabilities for rapid and sensitive measurements; however, significant challenges still exist in generating high-power, mutually coherent mid-infrared combs. Here we demonstrate that a pair of near-infrared femtosecond frequency combs can be spectrally translated via continuous-wave optical parametric oscillator. The high mutual coherence, power per comb tooth excess hundreds microwatts, were tunable between 4 um 5 um. Unlike previous...
Abstract. Studying tropospheric ozone over the remote areas of planet, such as open oceans and polar regions, is crucial to understand role a global climate forcer regulator atmospheric oxidative capacity. A focus on pristine oceanic regions complements available land-based data sets provides insights into key photochemical depositional loss processes that control concentrations, spatio-temporal variability ozone, physico-chemical mechanisms driving these patterns. However, an assessment has...
Abstract. The elevated deposition of atmospheric mercury over the southeastern United States is currently not well understood. Here we measure partial columns and vertical profiles bromine monoxide (BrO) radicals, a key component oxidation chemistry, to better understand processes altitudes at which being oxidized in atmosphere. We use data from ground-based MAX-DOAS instrument located coastal site ∼ 1 km Gulf Mexico Breeze, FL, where had previously detected tropospheric BrO (Coburn et al.,...
A new method is tested in a single-blind study for detection, attribution, and quantification of methane emissions from the natural gas supply chain, which contribute substantially to annual U.S. emissions. The monitoring approach couples atmospheric concentration measurements an open-path dual frequency comb laser spectrometer with meteorological data inversion characterize During testing, placed >1 km decommissioned equipment configured intentional leaks controllable rate. Single, steady...
Abstract. We present the first quantitative intercomparison between two open-path dual comb spectroscopy (DCS) instruments which were operated across adjacent 2-km open-air paths over a two-week period. used DCS to measure atmospheric absorption spectrum in near infrared from 6021 6388 cm−1 (1565 1661 nm), corresponding 367 bandwidth, at 0.0067 sample spacing. The measured spectra agree with each other within 5 × 10−4 without any external calibration of either instrument. are fit retrieve...
Providing an accurate, representative sample of mass flux across large open areas for atmospheric studies or the extreme conditions a hypersonic engine is challenging traditional intrusive point-based sensors. Here, we demonstrate that laser absorption spectroscopy with mode-locked frequency combs can simultaneously measure all components (velocity, temperature, pressure, and species mole fraction) low uncertainty, spatial resolution corresponding to line sight, no supplemental sensor...
Abstract. Stable carbon isotopic compositions of water-soluble organic (WSOC) and molecular markers were measured to investigate the relative contributions sea surface sources fraction submicron aerosols collected over eastern equatorial Pacific during Tropical Ocean tRoposphere Exchange Reactive halogens Oxygenated VOCs (TORERO)/KA-12-01 cruise. On average, total (TC) mass in was ∼ 30–35 % oceans with low chlorophyll a (Chl a) concentrations, whereas it 60 high-Chl regions. The average...
Temporal variability contributes to uncertainty in inventories of methane emissions from the natural gas supply chain. Extrapolation instantaneous, "snapshot-in-time" measurements, for example, can miss temporal intermittency and confound bottom-up/top-down comparisons. Importantly, no continuous long-term datasets record emission underground storage facilities despite substantial contributions sector-wide emissions. We present 11 months observations on a section site using dual-frequency...
Accurate diagnostics of the combustor region ramjet engines can improve engine design and create benchmarks for computational fluid dynamics models. Previous works demonstrate that dual frequency comb spectroscopy provide low uncertainty multiple flow parameters in non-combusting regions ramjets. However, high temperatures present a challenge broadband spectroscopic absorption models are used to interpret measurements these regions. Here, we utilize new water vapor database created...
Laser absorption Doppler velocimeters use a crossed-beam configuration to cancel errors due laser frequency drift and model uncertainty. This complicates the spatial interpretation of measurement since two beams sample different volumes gas. Here, we achieve single-beam velocimetry with portable dual comb spectrometer (DCS) high accuracy stability enabled by GPS-referencing, new high-temperature water vapor database. We measure inlet flow in supersonic ramjet engine demonstrate measurements...
Multi AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instruments, as solar straylight satellites, require an accurate characterization and elimination of Fraunhofer lines from spectra to measure the atmospheric column abundance reactive gases that destroy toxic heat trapping ozone form climate cooling aerosols, like glyoxal (CHOCHO), iodine oxide (IO), or bromine (BrO). The currently achievable noise levels with state-of-the-art DOAS instruments are limited...