In:
Atmospheric Measurement Techniques, Copernicus GmbH, Vol. 11, No. 8 ( 2018-08-08), p. 4583-4603
Abstract:
Abstract. Nine Pandora
spectrometer instruments (PSI) were installed at eight sites in
South Korea as part of the KORUS-AQ (Korea U.S.-Air Quality) field study
integrating information from ground, aircraft, and satellite measurements
for validation of remote sensing air-quality studies. The PSI made
direct-sun measurements of total vertical column NO2, C(NO2), with
high precision (0.05 DU, where 1 DU =2.69×1016 molecules cm−2)
and accuracy (0.1 DU) that were retrieved using spectral fitting techniques.
Retrieval of formaldehyde C(HCHO) total column amounts were also obtained at
five sites using the recently improved PSI optics. The C(HCHO) retrievals have
high precision, but possibly lower accuracy than for NO2 because of
uncertainty about the optimum spectral window for all ground-based and
satellite instruments. PSI direct-sun retrieved values for C(NO2) and
C(HCHO) are always significantly larger than OMI (AURA satellite Ozone
Monitoring Instrument) retrieved C(NO2) and C(HCHO) for the OMI
overpass local times (KST=13.5±0.5 h). In urban areas, PSI
C(NO2) 30-day running averages are at least a factor of two larger than
OMI averages. Similar differences are seen for C(HCHO) in Seoul and nearby
surrounding areas. Late afternoon values of C(HCHO) measured by PSI are even
larger, implying that OMI early afternoon measurements underestimate the
effect of poor air quality on human health. The primary cause of OMI
underestimates is the large OMI field of view (FOV) that includes regions
containing low values of pollutants. In relatively clean areas, PSI and OMI
are more closely in agreement. C(HCHO) amounts were obtained for five sites,
Yonsei University in Seoul, Olympic Park, Taehwa Mountain, Amnyeondo, and Yeoju.
Of these, the largest amounts of C(HCHO) were observed at Olympic Park and
Taehwa Mountain, surrounded by significant amounts of vegetation.
Comparisons of PSI C(HCHO) results were made with the Compact Atmospheric
Multispecies Spectrometer CAMS during overflights on the DC-8 aircraft for
Taehwa Mountain and Olympic Park. In all cases, PSI measured substantially more
C(HCHO) than obtained from integrating the CAMS altitude profiles. PSI
C(HCHO) at Yonsei University in Seoul frequently reached 0.6 DU and
occasionally exceeded 1.5 DU. The semi-rural site, Taehwa Mountain, frequently
reached 0.9 DU and occasionally exceeded 1.5 DU. Even at the cleanest site,
Amnyeondo, C(HCHO) occasionally exceeded 1 DU.
Type of Medium:
Online Resource
ISSN:
1867-8548
DOI:
10.5194/amt-11-4583-2018
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2018
detail.hit.zdb_id:
2505596-3
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