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Author
Liu, M. ; Lin, J. ; Wang, Y. ; Sun, Y. ; Zheng, B. ; Shao, J. ; Chen, L. ; Zheng, Y. ; Chen, J. ; Fu, T.-M. ; Yan, Y. ; Zhang, Q. ; Wu, Z.
Title
Spatiotemporal variability of NO2 and PM2.5 over Eastern China: observational and model analyses with a novel statistical method
Type
$loc['typeJournal Article']
Year
2018
Publication
Atmospheric Chemistry and Physics
Abbreviated Journal
Atmos. Chem. Phys.
Volume
18
Issue
17
Pages
12933-12952
Keywords
TROPOSPHERIC NITROGEN-DIOXIDE ; PROVINCIAL CAPITAL CITIES ; CRITERIA AIR-POLLUTANTS ; BOUNDARY-LAYER ; NORTH CHINA ; HILBERT SPECTRUM ; UNITED-STATES ; TIME-SERIES ; OZONE ; EMISSIONS
Abstract
Eastern China (27-41 degrees N, 110-123 degrees E) is heavily polluted by nitrogen dioxide (NO2), particulate matter with aerodynamic diameter below 2.5 mu m (PM2.5), and other air pollutants. These pollutants vary on a variety of temporal and spatial scales, with many temporal scales that are nonperiodic and nonstationary, challenging proper quantitative characterization and visualization. This study uses a newly compiled EOF-EEMD analysis visualization package to evaluate the spatiotemporal variability of ground-level NO2, PM2.5, and their associations with meteorological processes over Eastern China in fall-winter 2013. Applying the package to observed hourly pollutant data reveals a primary spatial pattern representing Eastern China synchronous variation in time, which is dominated by diurnal variability with a much weaker day-to-day signal. A secondary spatial mode, representing north-south opposing changes in time with no constant period, is characterized by wind-related dilution or a buildup of pollutants from one day to another. We further evaluate simulations of nested GEOS-Chem v9-02 and WRF/CMAQ v5.0.1 in capturing the spatiotemporal variability of pollutants. GEOS-Chem underestimates NO2 by about 17 mu g m(-3) and PM2.5 by 35 mu g m(-3 )on average over fall-winter 2013. It reproduces the diurnal variability for both pollutants. For the day-to-day variation, GEOS-Chem reproduces the observed north-south contrasting mode for both pollutants but not the Eastern China synchronous mode (especially for NO2). The model errors are due to a first model layer too thick (about 130 m) to capture the near-surface vertical gradient, deficiencies in the nighttime nitrogen chemistry in the first layer, and missing secondary organic aerosols and anthropogenic dust. CMAQ overestimates the diurnal cycle of pollutants due to too-weak boundary layer mixing, especially in the nighttime, and overestimates NO2 by about 30 mu g m(-3) and PM2.5 by 60 mu g m(-3). For the day-to-day variability, CMAQ reproduces the observed Eastern China synchronous mode but not the north-south opposing mode of NO2. Both models capture the day-to-day variability of PM2.5 better than that of NO2. These results shed light on model improvement. The EOF-EEMD package is freely available for noncommercial uses.
Address
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Thesis
Publisher
Place of Publication
Editor
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Summary Language
Original Title
Series Editor
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Abbreviated Series Title
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Series Issue
Edition
ISSN
1680-7324
ISBN
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Approved
$loc['no']
Call Number
COAPS @ user @
Serial
946
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Author
Yan, Y. ; Chassignet, E.P. ; Qi, Y. ; Dewar, W.K.
Title
Freshening of Subsurface Waters in the Northwest Pacific Subtropical Gyre: Observations and Dynamics
Type
$loc['typeJournal Article']
Year
2013
Publication
Journal of Physical Oceanography
Abbreviated Journal
J. Phys. Oceanogr.
Volume
43
Issue
12
Pages
2733-2751
Keywords
Abstract
Address
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Thesis
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Summary Language
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Series Editor
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ISSN
0022-3670
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Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
178
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Author
Yan, Y. ; Liu, Y. ; Lu, J.
Title
Cloud vertical structure, precipitation, and cloud radiative effects over Tibetan Plateau and its neighboring regions
Type
$loc['typeJournal Article']
Year
2016
Publication
Journal of Geophysical Research: Atmospheres
Abbreviated Journal
J. Geophys. Res. Atmos.
Volume
121
Issue
10
Pages
5864-5877
Keywords
Abstract
Address
Corporate Author
Thesis
Publisher
Place of Publication
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Language
Summary Language
Original Title
Series Editor
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Series Issue
Edition
ISSN
2169897X
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Medium
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Conference
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Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
59
Permanent link to this record