000890286 001__ 890286 000890286 005__ 20240712101033.0 000890286 0247_ $$2doi$$a10.5194/amt-13-2711-2020 000890286 0247_ $$2ISSN$$a1867-1381 000890286 0247_ $$2ISSN$$a1867-8548 000890286 0247_ $$2Handle$$a2128/27076 000890286 0247_ $$2WOS$$aWOS:000537699800002 000890286 037__ $$aFZJ-2021-00867 000890286 082__ $$a550 000890286 1001_ $$00000-0001-9417-587X$$aMarno, Daniel$$b0$$eCorresponding author 000890286 245__ $$aCalibration of an airborne HO<sub><i>x</i></sub> instrument using the All Pressure Altitude-based Calibrator for HO<sub><i>x</i></sub> Experimentation (APACHE) 000890286 260__ $$aKatlenburg-Lindau$$bCopernicus$$c2020 000890286 3367_ $$2DRIVER$$aarticle 000890286 3367_ $$2DataCite$$aOutput Types/Journal article 000890286 3367_ $$0PUB:(DE-HGF)16$$2PUB:(DE-HGF)$$aJournal Article$$bjournal$$mjournal$$s1611742631_26809 000890286 3367_ $$2BibTeX$$aARTICLE 000890286 3367_ $$2ORCID$$aJOURNAL_ARTICLE 000890286 3367_ $$00$$2EndNote$$aJournal Article 000890286 520__ $$aLaser-induced fluorescence (LIF) is a widely used technique for both laboratory-based and ambient atmospheric chemistry measurements. However, LIF instruments require calibrations in order to translate instrument response into concentrations of chemical species. Calibration of LIF instruments measuring OH and HO2 (HOx) typically involves the photolysis of water vapor by 184.9 nm light, thereby producing quantitative amounts of OH and HO2. For ground-based HOx instruments, this method of calibration is done at one pressure (typically ambient pressure) at the instrument inlet. However, airborne HOx instruments can experience varying cell pressures, internal residence times, temperatures, and humidity during flight. Therefore, replication of such variances when calibrating in the lab is essential to acquire the appropriate sensitivities. This requirement resulted in the development of the APACHE (All Pressure Altitude-based Calibrator for HOx Experimentation) chamber to characterize the sensitivity of the airborne LIF-FAGE (fluorescence assay by gas expansion) HOx instrument, HORUS, which took part in an intensive airborne campaign, OMO-Asia 2015. It utilizes photolysis of water vapor but has the additional ability to alter the pressure at the nozzle of the HORUS instrument. With APACHE, the HORUS instrument sensitivity towards OH (26.1–7.8 cts s−1 pptv−1 mW−1, ±22.6 % 1σ; cts stands for counts by the detector) and HO2 (21.2–8.1 cts s−1 pptv−1 mW−1, ±22.1 % 1σ) was characterized to the external pressure range at the instrument nozzle of 227–900 mbar. Measurements supported by a computational fluid dynamics model, COMSOL Multiphysics, revealed that, for all pressures explored in this study, APACHE is capable of initializing a homogenous flow and maintaining near-uniform flow speeds across the internal cross section of the chamber. This reduces the uncertainty regarding average exposure times across the mercury (Hg) UV ring lamp. Two different actinometrical approaches characterized the APACHE UV ring lamp flux as 6.37×1014(±1.3×1014) photons cm−2 s−1. One approach used the HORUS instrument as a transfer standard in conjunction with a calibrated on-ground calibration system traceable to NIST standards, which characterized the UV ring lamp flux to be 6.9(±1.1)×1014 photons cm−2 s−1. The second approach involved measuring ozone production by the UV ring lamp using an ANSYCO O3 41 M ozone monitor, which characterized the UV ring lamp flux to be 6.11(±0.8)×1014 photons cm−2 s−1. Data presented in this study are the first direct calibrations of an airborne HOx instrument, performed in a controlled environment in the lab using APACHE. 000890286 536__ $$0G:(DE-HGF)POF3-243$$a243 - Tropospheric trace substances and their transformation processes (POF3-243)$$cPOF3-243$$fPOF III$$x0 000890286 588__ $$aDataset connected to CrossRef 000890286 7001_ $$0P:(DE-HGF)0$$aErnest, Cheryl$$b1 000890286 7001_ $$0P:(DE-HGF)0$$aHens, Korbinian$$b2 000890286 7001_ $$0P:(DE-Juel1)173894$$aJaved, Umar$$b3$$ufzj 000890286 7001_ $$0P:(DE-HGF)0$$aKlimach, Thomas$$b4 000890286 7001_ $$0P:(DE-HGF)0$$aMartinez, Monica$$b5 000890286 7001_ $$00000-0002-4626-7734$$aRudolf, Markus$$b6 000890286 7001_ $$00000-0001-6307-3846$$aLelieveld, Jos$$b7 000890286 7001_ $$00000-0002-6868-714X$$aHarder, Hartwig$$b8 000890286 773__ $$0PERI:(DE-600)2505596-3$$a10.5194/amt-13-2711-2020$$gVol. 13, no. 5, p. 2711 - 2731$$n5$$p2711 - 2731$$tAtmospheric measurement techniques$$v13$$x1867-8548$$y2020 000890286 8564_ $$uhttps://juser.fz-juelich.de/record/890286/files/amt-13-2711-2020.pdf$$yOpenAccess 000890286 909CO $$ooai:juser.fz-juelich.de:890286$$pdnbdelivery$$pVDB$$pVDB:Earth_Environment$$pdriver$$popen_access$$popenaire 000890286 915__ $$0StatID:(DE-HGF)0200$$2StatID$$aDBCoverage$$bSCOPUS$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0160$$2StatID$$aDBCoverage$$bEssential Science Indicators$$d2020-08-27 000890286 915__ $$0LIC:(DE-HGF)CCBY4$$2HGFVOC$$aCreative Commons Attribution CC BY 4.0 000890286 915__ $$0StatID:(DE-HGF)0600$$2StatID$$aDBCoverage$$bEbsco Academic Search$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0100$$2StatID$$aJCR$$bATMOS MEAS TECH : 2018$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0501$$2StatID$$aDBCoverage$$bDOAJ Seal$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0500$$2StatID$$aDBCoverage$$bDOAJ$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0113$$2StatID$$aWoS$$bScience Citation Index Expanded$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0700$$2StatID$$aFees$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0150$$2StatID$$aDBCoverage$$bWeb of Science Core Collection$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)9900$$2StatID$$aIF < 5$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0510$$2StatID$$aOpenAccess 000890286 915__ $$0StatID:(DE-HGF)0030$$2StatID$$aPeer Review$$bASC$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0561$$2StatID$$aArticle Processing Charges$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)1150$$2StatID$$aDBCoverage$$bCurrent Contents - Physical, Chemical and Earth Sciences$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0300$$2StatID$$aDBCoverage$$bMedline$$d2020-08-27 000890286 915__ $$0StatID:(DE-HGF)0199$$2StatID$$aDBCoverage$$bClarivate Analytics Master Journal List$$d2020-08-27 000890286 9141_ $$y2020 000890286 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)173894$$aForschungszentrum Jülich$$b3$$kFZJ 000890286 9131_ $$0G:(DE-HGF)POF3-243$$1G:(DE-HGF)POF3-240$$2G:(DE-HGF)POF3-200$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$aDE-HGF$$bErde und Umwelt$$lAtmosphäre und Klima$$vTropospheric trace substances and their transformation processes$$x0 000890286 9201_ $$0I:(DE-Juel1)IEK-8-20101013$$kIEK-8$$lTroposphäre$$x0 000890286 9801_ $$aFullTexts 000890286 980__ $$ajournal 000890286 980__ $$aVDB 000890286 980__ $$aUNRESTRICTED 000890286 980__ $$aI:(DE-Juel1)IEK-8-20101013 000890286 981__ $$aI:(DE-Juel1)ICE-3-20101013