CrIS PANs megacity dataset for São Paulo and Lagos
Data files
Sep 14, 2023 version files 288.88 KB
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CrIS_PANs_Lagos_2016_2021.csv
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CrIS_PANs_Sao_Paulo_2016_2021.csv
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README.md
Abstract
The COVID-19 pandemic perturbed air pollutant emissions as cities shut down worldwide. Peroxyacyl nitrates (PANs) are important tracers of photochemistry that are formed through the oxidation of non-methane volatile organic compounds (NMVOCs) in the presence of nitrogen oxide radicals (NOx = NO + NO2). We use satellite measurements of free tropospheric PANs from the S-NPP Cross-Track Infrared Sounder (CrIS) over eight of the world’s megacities: Mexico City, Beijing, Los Angeles, Tokyo, São Paulo, Delhi, Lagos, and Karachi. We quantify the seasonal cycle of PANs over these megacities and find seasonal maxima in PANs correspond to seasonal peaks in local photochemistry. CrIS is used to explore changes in PANs in response to the COVID-19 lockdowns. Statistically significant changes to PANs occurred over two megacities: Los Angeles (PAN decreased) and Beijing (PAN increased). Our analysis suggests that large perturbations in NOx may not result in significant declines in NOx export potential of megacities.
README: CrIS PANs megacity dataset for São Paulo and Lagos
https://doi.org/10.5061/dryad.wpzgmsbtk
These data files contain all filtered CrIS PANs and CO tropospheric average mixing ratio retrievals over the São Paulo & Lagos urban megacity subregions.
Temporal Coverage of Data:
2016-01-01 to 2021-05-20
Daily satellite data for the entire megacity area at 13:30 LT.
Spatial extent of data:
latitude extents São Paulo: 23.39838°S - 23.689°S
longitude extents São Paulo: 46.36157°W - 46.80453°W
latitude extents Lagos: 6.451°N - 6.64°N
longitude extents Lagos: 3.23°E - 3.41°E
Data has been filtered as described in the manuscript.
To reproduce figures in submitted manuscript: Figures in the manuscript utilized daily means and monthly means.
Description of the data and file structure
seven columns of data: XPAN_orig, Correction, XH2O, Lat, Lon, Year, Month, Day, XCO, XPAN. variables are described below.
Variable | Units | Description |
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XPAN_orig | parts per billion by volume [ppbv] | XPAN800 value reported in datafile. <br>L2 variable called XPAN800. Tropospheric average of PANs from 800 hPa to the tropopause.<br>Missing data have been filtered out for various reasons. |
Correction | parts per billion by volume [ppbv] | Correction value to be added to XPAN_orig as described in Payne et al., 2022 |
XH2O | molecules/m2 | Reported total column water vapor value from L2 water valor files. Correction value uses this.<br>Correction formula has been applied in XPAN variable (below). |
Lat | degrees | Latitude <br>Max São Paulo: 23.39838<br>Min São Paulo: -23.689<br>Max Lagos: 6.64<br>Min Lagos: 6.451 |
Lon | degrees | Longitude<br>Max São Paulo: -46.36157<br>Min São Paulo: -46.80453<br>Max Lagos: 3.41<br>Min Lagos: 3.23 |
Year | Year | Format: YYYY<br>Max: 2021<br>Min: 2016 |
Month | Month | Format: MM |
Day | Day | Format: DD |
XCO | parts per billion by volume [ppbv] | Tropospheric average created using the L2 variable called “Species”. From 825 hPa - 215 hPa.<br>Missing data have been filtered out. |
XPAN | parts per billion by volume [ppbv] | Corrected XPAN value. This is the XPAN value to use going forward. |
Sharing/Access information
Other Megacity datasets:
Kevin W. Bowman (2023), TROPESS CrIS-SNPP L2 for Beijing Megacity, Summary Product V1, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed: [August 2022], 10.5067/GBMBES47TUOI
Mexico City, Tokyo, Karachi, Delhi, and Los Angeles are also available on the NASA GES DISC.
Uncertainty, precision, and accuracy of measurements
CrIS PAN algorithm description and further information can be found in:
Payne, Vivienne H., Kulawik, S. S., Fischer, E. V., Brewer, J. F., Huey, L. G., Miyazaki, K., Worden, J. R., Bowman, K. W., Hintsa, E. J., Moore, F., Elkins, J. W., & Juncosa Calahorrano, J. (2022). Satellite measurements of peroxyacetyl nitrate from the Cross-Track Infrared Sounder: comparison with ATom aircraft measurements. Atmospheric Measurement Techniques, 15(11), 3497–3511. https://doi.org/10.5194/amt-15-3497-2022
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Additional references:
Bowman, K. W., Rodgers, C. D., Kulawik, S. S., Worden, J., Sarkissian, E., Osterman, G., Steck, T., Lou, M., Eldering, A., Shephard, M., Worden, H., Lampel, M., Clough, S., Brown, P., Rinsland, C., Gunson, M., and Beer, R.: Tropospheric Emission Spectrometer: Retrieval method and error analysis. IEEE Trans. on Geosci. Remote Sensing, 44(5), 2006.
Fu, D., Kulawik, S. S., Miyazaki, K., Bowman, K. W., Worden, J. R., Eldering, A., Livesey, N. J.,
Teixeira, J., Irion, F. W., Herman, R. L., Osterman, G. B., Liu, X., Levelt, P. F., Thompson, A. M. and Luo, M.: Retrievals of tropospheric ozone profiles from the synergism of AIRS and OMI: methodology and validation, Atmos. Meas. Tech., 11(10), 5587–5605, doi:10.5194/amt-11-5587- 2018-supplement, 2018.
Worden, J., Kulawik, S., Frankenberg, C., Payne, V., Bowman, K., Cady-Pereira, K., Wecht, K.,
Lee, J.-E. and Noone, D.: Profiles of CH4, HDO, H2O, and N2O with improved lower
tropospheric vertical resolution from Aura TES radiances, Atmos. Meas. Tech., 5(2), 397–411, doi:10.5194/amt-5-397-2012, 2012.