دورية أكاديمية
Modification, calibration, and performance of the Ultra-High Sensitivity Aerosol Spectrometer for particle size distribution and volatility measurements during the Atmospheric Tomography Mission (ATom) airborne campaign
| العنوان: | Modification, calibration, and performance of the Ultra-High Sensitivity Aerosol Spectrometer for particle size distribution and volatility measurements during the Atmospheric Tomography Mission (ATom) airborne campaign |
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| المؤلفون: | A. Kupc, C. Williamson, N. L. Wagner, M. Richardson, C. A. Brock |
| المصدر: | Atmospheric Measurement Techniques, Vol 11, Pp 369-383 (2018) |
| بيانات النشر: | Copernicus Publications, 2018. |
| سنة النشر: | 2018 |
| المجموعة: | LCC:Environmental engineering LCC:Earthwork. Foundations |
| مصطلحات موضوعية: | Environmental engineering, TA170-171, Earthwork. Foundations, TA715-787 |
| الوصف: | Atmospheric aerosol is a key component of the chemistry and climate of the Earth's atmosphere. Accurate measurement of the concentration of atmospheric particles as a function of their size is fundamental to investigations of particle microphysics, optical characteristics, and chemical processes. We describe the modification, calibration, and performance of two commercially available, Ultra-High Sensitivity Aerosol Spectrometers (UHSASs) as used on the NASA DC-8 aircraft during the Atmospheric Tomography Mission (ATom). To avoid sample flow issues related to pressure variations during aircraft altitude changes, we installed a laminar flow meter on each instrument to measure sample flow directly at the inlet as well as flow controllers to maintain constant volumetric sheath flows. In addition, we added a compact thermodenuder operating at 300 °C to the inlet line of one of the instruments. With these modifications, the instruments are capable of making accurate (ranging from 7 % for Dp Dp > 0.13 µm), precise ( 1000 to 225 hPa, while simultaneously providing information on particle volatility.We assessed the effect of uncertainty in the refractive index (n) of ambient particles that are sized by the UHSAS assuming the refractive index of ammonium sulfate (n = 1.52). For calibration particles with n between 1.44 and 1.58, the UHSAS diameter varies by +4/−10 % relative to ammonium sulfate. This diameter uncertainty associated with the range of refractive indices (i.e., particle composition) translates to aerosol surface area and volume uncertainties of +8.4/−17.8 and +12.4/−27.5 %, respectively. In addition to sizing uncertainty, low counting statistics can lead to uncertainties of 1000 cm−3.Examples of thermodenuded and non-thermodenuded aerosol number and volume size distributions as well as propagated uncertainties are shown for several cases encountered during the ATom project. Uncertainties in particle number concentration were limited by counting statistics, especially in the tropical upper troposphere where accumulation-mode concentrations were sometimes −3 (counting rates ∼ 5 Hz) at standard temperature and pressure. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 1867-1381 1867-8548 |
| Relation: | https://www.atmos-meas-tech.net/11/369/2018/amt-11-369-2018.pdf; https://doaj.org/toc/1867-1381; https://doaj.org/toc/1867-8548 |
| DOI: | 10.5194/amt-11-369-2018 |
| URL الوصول: | https://doaj.org/article/7cfae8acade74f7e86e47696dc2920ec |
| رقم الأكسشن: | edsdoj.7cfae8acade74f7e86e47696dc2920ec |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 18671381 18678548 |
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| DOI: | 10.5194/amt-11-369-2018 |