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At least 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Validating a microphysical prognostic stratospheric aerosol implementation in E3SMv2 using observations after the Mount Pinatubo eruption

Abstract. This paper describes the addition of a stratospheric prognostic aerosol (SPA) capability – developed with the goal of accurately simulating sulfate aerosol formation and evolution in the stratosphere – in the Department of Energy (DOE) Energy Exascale Earth System Model, version 2 (E3SMv2). The implementation includes changes to the four-mode Modal Aerosol Module microphysics in the stratosphere to allow for larger particle growth and more accurate stratospheric aerosol lifetime following the Pinatubo eruption. E3SMv2-SPA reasonably reproduces stratospheric aerosol lifetime, burden, aerosol optical depth, and top-of-atmosphere flux when compared to remote sensing observations. E3SMv2-SPA also has close agreement with the interactive chemistry–climate model CESM2-WACCM (Community Earth System Model version 2–Whole Atmosphere Community Climate Model) – which has a more complete chemical treatment – and the observationally constrained, prescribed volcanic aerosol treatment in E3SMv2. Global stratospheric aerosol size distributions identify the nucleation and growth of sulfate aerosol from volcanically injected SO2 from both major and minor volcanic eruptions from 1991 to 1993. The modeled aerosol effective radius is consistently lower than satellite and in situ measurements (max differences of ∼ 30 %). Comparisons with in situ size distribution samples indicate that this simulated underestimation in both E3SMv2-SPA and CESM2-WACCM is due to overly small accumulation and coarse-mode aerosols 6–18 months post-eruption, with E3SMv2-SPA simulating ∼ 50 % of the coarse-mode geometric mean diameters of observations 11 months post-eruption. Effective radii from the models and observations are used to calculate offline scattering and absorption efficiencies to explore the implications of smaller simulated aerosol size for the Pinatubo climate impacts. Scattering efficiencies at wavelengths of peak solar irradiance (∼ 0.5 µm) are 10 %–80 % higher for daily samples in models relative to observations through 1993, suggesting higher diffuse radiation at the surface and a larger cooling effect in the models due to the smaller simulated aerosol; absorption efficiencies at the peak wavelengths of outgoing terrestrial radiation (∼ 10 µm) are 15 %–40 % lower for daily samples in models relative to observations, suggesting an underestimation in stratospheric heating in the models due to the smaller simulated aerosol. These potential biases are based on aerosol size alone and do not take into account differences in the aerosol number. The overall agreement of E3SMv2-SPA with observations and its similar performance to the well-validated CESM2-WACCM makes E3SMv2-SPA a viable alternative to simulating climate impacts from stratospheric sulfate aerosols.

Brown, Hunter York (ORCID:0000000218147874)↗
DOE OSTI2024

Size resolved particle hygroscopcity for 30, 60, and 90 nm particles collected at the EPCAPE Mount Soledad site from 04/20/2023 to 06/15/2023

Contains both the growth factor probability density function (probability is out of 200) and the average growth factors calculated by the Gysel inversion. The instrument measured three different diameters 30 nm, 60nm and 90nm each diameter was selected for an hour. During that hour, five 12-minute scans were taken scanning growth factors from 0.5-3.0. RH was consistently kept at 85%. Calibrations of the instrument with NaCl were performed on 4/26/2023 from 11:20 to 14:20, on 5/16/2023 from 11:40 to 16:00, and on 5/30/2023 from 10:20 to 14:20. Calibrations with (NH4)2SO4 were performed on 5/8/2023 from 11:45 to 14:40, on 5/23/2023 from 11:20 to 3:00, and on 6/14/2023 from 13:00 to 16:00. Time is recorded in seconds since 1/1/1904.

30 nm particle hygroscopicity↗
DOE OSTI2024

Size resolved particle volatility for 30, 60, and 90 nm particles collected at the EPCAPE Mount Soledad site from 04/23/2023 to 06/15/2023

VTDMA GF-PDF: Growth factor probability density functions from the Gysel inversion are located here, where probability is out of 200. The instrument measured three different diameters 30 nm, 60nm and 90nm each diameter was selected for an hour. During that hour three different temperatures where scanned (40°C, 80°C, 160°C) in between each temperature a bypass scan was taken at room temperature. Each scan took 10-minutes and scanned growth factors from 0.2-1.2. Calibrations of the instrument with NaCl were performed on 4/26/2023 from 11:20 to 14:20, on 5/16/2023 from 11:40 to 16:00, and on 5/30/2023 from 10:20 to 14:20. Calibrations with (NH4)2SO4 were performed on 5/8/2023 from 11:45 to 14:40, on 5/23/2023 from 11:20 to 3:00, and on 6/14/2023 from 13:00 to 16:00. Time is recorded in seconds since 1/1/1904. GF_Vol_avg: Growth factor volume average calculated by the Gysel inversion. The instrument measured three different diameters 30 nm, 60nm and 90nm each diameter was selected for an hour. During that hour three different temperatures where scanned (40°C, 80°C, 160°C) in between each temperature a bypass scan was taken at room temperature. Each scan took 10-minutes and scanned growth factors from 0.2-1.2. Calibrations of the instrument with NaCl were performed on 4/26/2023 from 11:20 to 14:20, on 5/16/2023 from 11:40 to 16:00, and on 5/30/2023 from 10:20 to 14:20. Calibrations with (NH4)2SO4 were performed on 5/8/2023 from 11:45 to 14:40, on 5/23/2023 from 11:20 to 3:00, and on 6/14/2023 from 13:00 to 16:00. Time is recorded in seconds since 1/1/1904.

30nm growth factor volume average at 160C (GF_vol_↗
DOE OSTI2024

Orbitrap LC-MS Analysis of Nanoparticle Composition at the EPCAPE Mount Soledad site between 04 18 2023 and 06 14 2023

Weekly peak lists containing m/z, intensity, and assigned formula for filter samples, size selected for sub-100 nm particles. Filters were collected daily between 4/18/23 and 6/14/23, grouped based on calendar week for extraction, and analyzed via Thermo Scientific Q Exactive Plus Orbitrap LC-MS. Formulas were assigned to background-corrected peak lists and restricted to CHONS/CHONSNa atoms for the negative and positive modes respectively. Filters were grouped into calendar weeks 0-8 with dates provided in README text file.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Parts per Billion Concentrations of Volatile Organic Gases collected with a PTRMS at the EPCAPE Mount Soledad site from 05-20-2023 to 06-15-2023

This dataset contains the parts per billion concentrations of various volatile organic gases. Data was collected using a Proton Transfer Reaction Mass Spectrometer (PTRMS). Concentrations for all compounds were calculated using a reaction constant (k-value) of 2.0E-9 cm^3/s. On June 14, a calibration was preformed for the gases methanol, acetone, isoprene, butanone, benzene and toluene. Calibrations curves were used to correct the concentrations of these gases. Negative concentration values were replaced with zeros. Other gases were not calibrated for. Data has undergone one minute averaging. Time data is in coordinated universal time (UTC). Time has been recorded in seconds since 1/1/1904.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Particle composition measurements for ultrafine particles collected at the EPCAPE Mount Soledad site from 04-27-2023 to 06-13-2023 using a Thermal Desorption Chemical Ionization Mass Spectrometer

The dataset contains particle composition data for both the positive and negative reagent ion modes of the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS). The dataset is split into two directories: one for particles with diameters of 30 nm and the other for particles with diameters of less than 100 nm. The positive reagent ion mode uses H3O+ as the reagent ion, and ionization usually occurs through hydrogen addition. The negative mode uses O2- as the reagent ion. Negative mode ionization generally occurs through hydrogen abstraction, but O2- addition is also possible. Ion concentrations were normalized to total ion counts, and unknown ions were then removed from the data. The name of each ion fraction time series includes the mass to charge ratio and the chemical formula for the ion. Time is recorded in seconds since 1/1/1904. The time zone is UTC.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1964

Mounting for diodes provides efficient heat sink

Efficient heat sink is provided by soldering diodes to metal support bars which are brazed to a ceramic base. Electrical connections between diodes on adjacent bars are made flexible by metal strips which aid in heat dissipation.

Source record↗
NASA NTRS1966

Mount makes liquid nitrogen-cooled gamma ray detector portable

Liquid nitrogen-cooled gamma ray detector system is made portable by attaching the detector to a fixture which provides a good thermal conductive path between the detector and the liquid nitrogen in a dewar flask and a low heat leak path between the detector and the external environment.

Fessler, T. E.↗
NASA NTRS1966

Mounting facilitates removal and installation of flame-detector rods

Flame-detector-rod holder is easily removed from the wall of a gas-fired furnance for maintenance or replacement of the detector rod without requiring shutdown of the furnace. The holder consists of an externally threaded outer bushing, a sleeve which is held inside the outer bushing with a set screw, and a detector rod assembly which screws into the sleeve.

Castle, F.↗
NASA NTRS1968

Telescope mount with azimuth-only primary

In large aperture telescope primary reflectors, the primary mirror is fixed with respect to the gravity vector to avoid varying gravity deflection problems. The primary reflector does not become distorted in various positions nor in changing positions.

Wells, W. H.↗