10.6078/D1KS3M
1
2016-12-01Z
Creative Commons Attribution 4.0 International (CC BY 4.0)
https://creativecommons.org/licenses/by/4.0/
none
none
2016-12-01Z
2016-12-01Z
10.6078/D1KS3M
Laughner, Joshua
0000-0002-8599-4555
University of California, Berkeley
BErkeley High Resolution (BEHR) OMI NO2 Prototype High Temporal
Resolution Product
University of California, Berkeley
2016
OMI
NO2
nitrogen dioxide
ozone monitoring instrument
BEHR
Berkeley High Resolution NO2
National Aeronautics and Space Administration
NNX14AK89H
National Aeronautics and Space Administration
NNX15AE37G
National Aeronautics and Space Administration
NNX14AH04G
Smithsonian Institution
SV3-83019
en
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Creative Commons Attribution 4.0 International (CC BY 4.0)
The BErkeley High Resolution (BEHR) OMI NO2 Prototype High Temporal
Resolution Product makes use of high spatial and temporal resolution a
priori NO2 profiles for a limited domain in the southeast United
States, covering 1 June-30 Aug 2013. These retrievals have been used
to evaluate the impact of daily temporal resolution of the
high-spatial-resolution a priori NO2 profiles needed for the retrieval
Tropospheric slant columns are obtained from the NASA OMI Standard
Product v2.1 (SP2). Tropospheric air mass factors (AMFs) are computed
using the scattering weights from the SP2 look up table and a priori
NO2 profiles simulated with WRF-Chem at 12 km spatial resolution.
Inputs to the scattering weight look up table are the sun-satellite
geometry, surface albedo from the MODIS combined black-sky albedo
product (MCD43C3) and the terrain heights from the Global Land One-km
Base Elevation (GLOBE) project database
(https://www.ngdc.noaa.gov/mgg/topo/globe.html). The AMF for each
pixel is the average of clear and cloudy AMFs; weighted by the cloud
radiance fraction for that pixel. Cloudy AMFs use the OMI O2-O2 cloud
pressure as the surface pressure and 0.8 as the cloud albedo. These
AMFs are used to compute the BEHR tropospheric vertical column
densities (VCDs).
There are nine .zip archives containing retrievals for the period 1
June-30 Aug 2013. The three .zip files marked "pseudo"
contain pseudo-retrievals for this period; these retrievals use the
same set of OMI pixels for all days. Thus, VCDs are not included in
these files, only the BEHR AMFs. The purpose is to show the impact of
daily vs. NO2 profiles on the AMFs. The three pseudo-retrieval zip
archives differ only in the NO2 profiles used: daily profiles, monthly
average profiles, or hybrid profiles, which use daily profiles below
750 hPa and monthly average above. The other six .zip archives (marked
"prototype") contain full retrievals with the actual pixels
for each day. Again, three different sets of NO2 a priori profiles are
used, daily, monthly average, and coarse monthly average profiles
(simulated at 108 km spatial resolution). The "native" files
contain data at the native OMI pixel resolution; the
"gridded" files contain this data oversampled to a 0.05x0.05
degree grid. The latter is easier to average over time, since the
geographic coordinates of each grid cell is fixed from day to day.
This data should be filtered for quality by the vcdQualityFlags and
XTrackQualityFlags fields. Only pixels where vcdQualityFlags is an
even integer and XTrackFlags is 0 should be used. Cloud filtering is
also recommended for most applications; we require that CloudFraction
is less than or equal to 0.2. Although the full prototype retrievals
contain pixels throughout the continental US, only pixels within the
approximate domain 89 to 79 deg. W and 30 to 38 deg. N have valid
data.