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O3 Photometer - UAS (NOAA)

Ozone (O3) in the lower stratosphere (LS) is responsible for absorbing much of the biologically damaging ultraviolet (UV) radiation from the sunlight, and thus plays a critical role in protecting Earth's environment. By absorbing UV light, O3 heats the surrounding air, leading to the vertical stratification and dynamic stability that define the stratosphere. Halogen species from anthropogenic compounds such as CFCs can cause significant damage to the O3 layer in the LS and have led to the formation of the Antarctic ozone hole. Accurate measurement of O3 in the LS is the first step toward understanding and protecting stratospheric O3. The UAS Ozone Photometer was designed specifically for autonomous, precise, and accurate O3 measurements in the upper troposphere and lower stratosphere (UT/LS) onboard the NASA Global Hawk Unmanned Aircraft System (GH UAS) and other high altitude research platforms such as the ER-2 and WB-57. With a data rate of 2 Hz, the instrument can provide high-time-resolution, detailed information for studies of O3 photochemistry, radiation balance, stratosphere-troposphere exchange, and air parcel mixing in the UT/LS. Furthermore, its accurate data are useful for satellite retrieval validation.  Contacts: Troy Thornberry, Ru-Shan Gao

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O3 Photometer (NOAA)

Ozone (O3) in the lower stratosphere (LS) is responsible for absorbing much of the biologically damaging ultraviolet (UV) radiation from the sunlight, and thus plays a critical role in protecting Earth's environment. By absorbing UV light, O3 heats the surrounding air, leading to the vertical stratification and dynamic stability that define the stratosphere. Manmade halogen compounds, such as CFCs, cause significant damage to the O3 layer in the LS and lead to the formation of the Antarctic ozone hole. Accurate measurement of O3 in the LS is the first step toward understanding and protecting stratospheric O3. The Ozone Photometer was designed specifically for autonomous, precise, and accurate O3 measurements in the upper troposphere and lower stratosphere (UT/LS). Flown for thousands of hours onboard the NASA ER-2, NASA WB-57, and NSF GV high-altitude aircraft, this instrument has played a key role in improving our understanding of O3 photochemistry in the UT/LS. Furthermore, its accurate data has been used, and continues to be highly sought after, for satellite validation, and studies of radiation balance, stratosphere-troposphere exchange, and air parcel mixing. Contacts: Ru-Shan Gao, David Fahey, Troy Thornberry, Laurel Watts, Steve Ciciora

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Gulfstream V - NSF, WB-57 - JSC, Global Hawk - AFRC
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Small Ice Detector

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C-130H - WFF, DC-8 - AFRC, Gulfstream V - NSF, WB-57 - JSC
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Soluble Acidic Gases and Aerosols

As part of the measurement team on the NASA DC-8 we operate two related installations: a mist chamber/ion chromatograph (MC/IC) sampling/analysis system providing near real time results for selected species, and a bulk aerosol system that collects particulates onto filters for subsequent analysis. We use ion chromatography on aqueous extracts of the bulk aerosol samples collected on Teflon filters to quantify soluble ions (Cl-, Br-, NO3-, SO42-, C2O42-, Na+, NH4+, K+, Ca+, and Mg+). Filters are exposed on all level flight legs. Below 3 km exposure times are 5 minutes or less, increasing at higher altitudes to a maximum sample time of 15 minutes. Aerosols participate in heterogeneous chemistry, impact radiative transfer, and can be detected from space. Our measurements help to validate and extend retrievals of aerosol distributions and properties by MODIS, MISR and CALIPSO. In addition, several of the particle-associated ions are tracers of sources of gas and aerosol pollutants (e.g., SO42- from industrial emissions of SO2, enhancements of C2O42-, K+, and NH4+ indicate encounters with biomass burning plumes, Na+, and Cl- are tracers of seasalt, Mg2+ and Ca2+ are tracers of dust). Our system has two inlets, allowing collection of paired samples simultaneously.

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Langley In Situ Fast-Response Ozone Measurements

• Technique: Chemluminescent reaction of ozone with nitric oxide
• Dynamic Range: 0.6 - 1600 ppb
• Accuracy: 5% or 2 ppb
• Precision: 2% or 0.6 ppb
• Response: 2-3 Hz; recorded at 6 Hz, reported at 1 Hz, faster data on request
• Spatial Resolution: <10 m vertical (aircraft spiral), 200 m horizontal (at 400 kts)

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Whole Air Sampler

The UC-Irvine research group collected whole air samples aboard the NASA DC-8 aircraft during the summer 2019 NASA Fire Influence on Regional to Global Environments Experiment - Air Quality (FIREX-AQ) field mission. More than 70 trace gases were identified and quantified at our Irvine laboratory, including C2-C10 NMHCs, C1-C2 halocarbons, C1-C5 alkyl nitrates, and selected sulfur compounds using our established technique of airborne whole air sampling followed by laboratory analysis using gas chromatography (GC) with flame ionization detection (FID), electron capture detection (ECD), and mass spectrometric detection (MSD). Our experimental procedures build on those that have been successfully employed for numerous prior NASA field missions, for example PEM Tropics A and B, TRACE-P, INTEX-A and B, ARCTAS, DC-3, SEAC4RS, ATom, KORUS-AQ, FIREX-AQ, and SARP.

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Single Particle Soot Photometer (NOAA)

The SP2 is a laser-induced incandescence instrument primarily used for measuring the refractory BC  (rBC) mass content of individual accumulation-mode aerosol particles. It is able to provide this data product independently of the total particle morphology and mixing state, and thus delivers detailed information not only about BC loadings, but also size distributions, even in exceptionally clean air. The instrument can also provide the optical size of individual particles containing rBC, and identify the presence of materials associated with the BC fraction (i.e. identify the rBC’s mixing state). Since its introduction in 2003, the SP2 has been substantially improved, and now can be considered a highly competent instrument for assessing BC loadings and mixing state in situ.  NOAA deploys multiple SP2s with different designs: the first was built for the WB-57F research aircraft. Two others are rack-mounted units customized at NOAA; one of the rack mounted units can be humidified, and has been deployed with a paired dry rack-mounted SP2 as the "Humidified-Dual SP2" (HD-SP2). The rack mounted units are suitable for in-cabin operations.

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Whole Air Sampler

The Whole Air Sampler (WAS) collects samples from airborne platforms for detailed analysis of a wide range of trace gases. The compounds that are typically measured from the WAS includes trace gases with sources from industrial midlatitude emissions, from biomass burning, and from the marine boundary layer, with certain compounds (e.g. organic nitrates) that have a unique source in the equatorial surface ocean. The use of a broad suite of tracers with different sources and lifetimes provides powerful diagnostic information on air mass history and chemical processing that currently is only available from measurements from whole air samples. Previous deployments of the whole air sampler have shown that the sampling and analytical procedures employed by our group are capable of accessing the wide range of mixing ratios at sufficient precision to be used for tracer studies. Thus, routine measurement of species, such as methyl iodide, at <= 0.1 x 10-12 mole fraction, or NMHC at levels of a few x 10-12 mole fraction are possible. In addition to the tracer aspects of the whole air sampler measurements, we measure a full suite of halocarbon species that provide information on the role of short-lived halocarbons in the tropical UT/LS region, on halogen budgets in the UT/LS region, and on continuing increasing temporal trends of HFCs (such as 134a), HCFCs (such as HCFC 141b), PFCs (such as C2F6), as well as declining levels of some of the major CFCs and halogenated solvents. The measurements of those species that are changing rapidly in the troposphere also give direct indications of the age and origin of air entering the stratosphere.

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Solar Spectral Flux Radiometer

In early 2000, the Ames Atmospheric Radiation Group completed the design and development of an all new Solar Spectral Flux Radiometer (SSFR). The SSFR is used to measure solar spectral irradiance at moderate resolution to determine the radiative effect of clouds, aerosols, and gases on climate, and also to infer the physical properties of aerosols and clouds. Additionally, the SSFR was used to acquire water vapor spectra using the Ames 25-meter base-path multiple-reflection absorption cell in a laboratory experiment. The Solar Spectral Flux Radiometer is a moderate resolution flux (irradiance) spectrometer with 8-12 nm spectral resolution, simultaneous zenith and nadir viewing. It has a radiometric accuracy of 3% and a precision of 0.5%. The instrument is calibrated before and after every experiment, using a NIST-traceable lamp. During field experiments, the stability of the calibration is monitored before and after each flight using portable field calibrators. Each SSFR consists of 2 light collectors, which are either fix-mounted to the aircraft fuselage, or on a stabilizing platform which counteracts the movements of the aircraft. Through fiber optic cables, the light collectors are connected to 2 identical pairs of spectrometers, which cover the wavelength range from (a) 350 nm-1000 nm (Zeiss grating spectrometer with Silicon linear diode array) and (b) 950 nm - 2150 nm (Zeiss grating spectrometer with InGaAs linear diode array). Each spectrometer pair covers about 95% of the incoming solar incident irradiance spectrum.

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PAN and Trace Hydrohalocarbon ExpeRiment

PANTHER uses Gas Chromatography with Electron Capture Detection and (GC-ECD) and Gas Chromatography with Mass Selective Detection (GC-MSD) to measure numerous trace gases, including methyl halides, HCFCs, peroxyacetyl nitrate, nitrous oxide, SF6, CFC-12, CFC-11, Halon-1211, methyl chloroform, carbon tetrachloride.

3 ECDs with packed columns (OV-101, Porapak-Q, molecular sieve).

1 ECD with a TE (thermal electric) cooled RTX-200 capillary column.

2-channel MSD (mass selective detector). The MSD analyzes two independent samples air concentrated onto TE cooled Haysep traps, which are then heated to desorb the analytes and separate using through two temperature programmed RTX-624 capillary columns.

With the exception of PAN, all channels of chromatography are normalized to a stable in-flight calibration gas references to NOAA scales. The PAN data are normalized to an in-flight PAN source of ≈ 100 ppt with ±5 % reproducibility. This source is generated by efficient photolytic conversion of NO in the presence of acetone. Detector non-linearity is taken out by lab calibrations for all molecules.

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