DOI: 10.15139/s3/erhaaz
title: EQUATES CMAQv5.3.2 CB6r5 High Resolution Deposition Data -- 1/1/2002 - 12/31/2019 300 m CONUS

description: &lt;h2&gt;Data Summary&lt;/h2&gt;&lt;p&gt;CMAQv5.3 Gridded High Resolution Dry Deposition (300m x 300m) for &lt;strong&gt;CB6r5 chemical mechanism&lt;/strong&gt; from EQUATES simulations from 01/01/2002 - 12/31/2019 over the Continental US.&lt;br&gt; 

&lt;br&gt;

&lt;strong&gt;Note:&lt;/strong&gt; The datasets are part of the CMAS Center Amazon Web Services (AWS) Open Data Program and are saved in an &lt;a href=https://aws.amazon.com/s3/&gt;AWS S3 bucket&lt;/a&gt;. The metadata associated with this DOI contain the link to the S3 bucket and instructions for downloading the data.
description: &lt;h2&gt;File Location and Download Instructions&lt;/h2&gt;

&lt;ul&gt; &lt;li&gt;&lt;strong&gt;&lt;a href=https://land-use-specific-deposition.s3.amazonaws.com/index.html&gt; Link to 2002 to 2019 Dry Deposition fields at 300m x 300m horizontal grid spacing. &lt;/a&gt;&lt;/strong&gt; &lt;/li&gt;

&lt;li&gt; &lt;strong&gt;&lt;a href=https://land-use-specific-deposition.s3.amazonaws.com/readme.html &gt;Link to download instructions&lt;/a&gt;&lt;/strong&gt; &lt;/li&gt; &lt;/ul&gt;

This S3 bucket contains gridded annual dry deposition estimates from 2002 to 2019 from the Environmental Protection Agency’s Community Multiscale Air Quality (CMAQ) model &lt;a href=https://github.com/USEPA/CMAQ/tree/5.3.2&gt; version 5.3.2 &lt;/a&gt; with the revised Surface Tiled Aerosol and Gaseous Exchange (STAGE) model (&lt;a href=https://doi.org/10.5194/acp-23-9911-2023&gt; Clifton et al., 2023 &lt;/a&gt;; &lt;a href=https://doi.org/10.5194/gmd-14-2867-2021&gt;Appel et al., 2021&lt;/a&gt;) created for the EPA’s Air QUAlity TimE Series (&lt;a href=https://www.epa.gov/cmaq/equates&gt;EQUATES&lt;/a&gt;) project. These deposition fields have been downscaled from the native 12 km resolution to 300 m by mapping STAGE land use specific deposition to Moderate Resolution Imaging Spectrometer (MODIS) 17 category International Geosphere-Biosphere Programme (IGBP) classification scheme. For details on model inputs, please refer to the EPA’s &lt;a href=https://www.epa.gov/cmaq/equates&gt;EQUATES &lt;/a&gt; project and &lt;a href=https://doi.org/10.5194/acp-22-12749-2022&gt;Benish et al., 2022&lt;/a&gt;.
description: &lt;h3&gt; Methodology &lt;/h3&gt;

&lt;p&gt;Annual accumulated CMAQ 300 m resolution data were created with post-scripts dry deposition species for the 12km conterminous US (CONUS) domain. The units of these output variables are kg-N/ha for nitrogen species, kg/ha for ozone, and kg-S/ha for sulfur containing species. Following chemical speciation defined in the Carbon Bond 6 revision 3 (CB6r3) mechanism:&lt;/p&gt;

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Species name and description (units) of the downscaled deposition fields.&lt;br&gt;
&lt;br&gt;
&lt;ul&gt; &lt;li&gt;DDEP_ANH4 = Aerosol NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_ANO3 = Aerosol NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_ANORG = Aerosol Organic Nitrogen (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_ASO4 = Aerosol SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt; (kg-S/ha)&lt;/li&gt;
&lt;li&gt;DDEP_HNO3 = HNO&lt;sub&gt;3&lt;/sub&gt; (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_HONO = HNO&lt;sub&gt;2&lt;/sub&gt; (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_N2O5 = N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_NH3 = NH&lt;sub&gt;3&lt;/sub&gt; (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_NO = NO (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_NTR = Organic Nitrates (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_O3. = O&lt;sub&gt;3&lt;/sub&gt; (kg/ha)&lt;/li&gt;
&lt;li&gt;DDEP_PANT. = Total peroxyacylnitrates (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_PNA = Peroxynitric Acid HNO&lt;sub&gt;4&lt;/sub&gt; (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DDEP_SO2. = SO&lt;sub&gt;2&lt;/sub&gt; (kg-S/ha)&lt;/li&gt;
&lt;li&gt;DD_OXN_NOX = DDEP_NO2 + DDEP_NO (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DD_OXN_ORGN = DDEP_NTR + DDEP_PANT + DDEP_ANORG (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DD_OXN_TNO3 = DDEP_HNO3 + DDEP_NO3 + DDEP_ANO3 (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DD_OXN_TOT = DD_OXN_NOX + DD_OXN_ORGN + DD_OXN_TNO3 + &lt;li&gt;DDEP_N2O5 + DDEP_HONO + DDEP_PNA (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DD_REDN_TOT = DDEP_NH3 + DDEP_ANH4 (kg-N/ha)&lt;/li&gt;
&lt;li&gt;DD_S_TOT = DDEP_ASO4 + DDEP_SO2 (kg-S/ha)&lt;/li&gt;
&lt;li&gt;DD_N_TOT = DD_OXN_TOT + DD_REDN_TOT (kg-S/ha)&lt;/li&gt;
&lt;/ul&gt;
&lt;br&gt;
The naming convention of the files is as follows:&lt;br&gt;
&lt;br&gt;
[Species name]_SUM _[Year]_MCD12Q1_Highres_dep_12US1.tif 
&lt;br&gt;
&lt;br&gt;
Where [Species name] is from the list above and [Year] is the year of the annual CMAQ simulation.&lt;br&gt;
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&lt;h3&gt; File Description &lt;/h3&gt;&lt;br&gt;
&lt;br&gt;
&lt;p&gt;The data are provided as annual GeoTIFFs for each species and year. The file header contains the projection and grid resolution information. The data are mapped to on a geographic latitude and longitude projection using the WGS84 datum. These files can be viewed and processed with geographic information system (GIS) software or statistical and analysis scientific software, e.g. R or Python. &lt;br&gt;&lt;/p&gt;
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&lt;h3&gt; Caveats Associated with Data &lt;/h3&gt; &lt;br&gt;
&lt;br&gt;
&lt;p&gt;CMAQ continues to be updated and more recent versions of the model contain new capabilities that will affect the predictions of deposition. Similarly, revisions in the emissions used in the model will change deposition estimates. For example, prior to the EQUATES simulation a bug was found in CMAQ that can result anomalously high emissions of NH&lt;sub&gt;3&lt;/sub &gt;under dry soil moisture conditions for the MODIS agricultural mosaic category (&lt;a href=https://www.epa.gov/cmaq/equates&gt;https://www.epa.gov/cmaq/equates&lt;/a&gt;). Furthermore, recent measurements of soil nitrogen in arid agricultural conditions indicate poor model performance in modeling soil nitrogen pools and emissions (&lt;a href= https://doi.org/10.3390/atmos15010015&gt;Leytem et al. 2024&lt;/a&gt;). This poor performance was related to a soil moisture bug, which was largely isolated to a small number of grid cells in the Southwest and this has been corrected in &lt;a href=https://github.com/USEPA/CMAQ/tree/5.4&gt; CMAQ v5.4&lt;/a&gt;. Also, measurements are currently planned to better understand the nitrogen dynamics under arid conditions which could result in further refinements to the modeling of soil moisture.&lt;/p&gt;