DOI: 10.5281/zenodo.14996969
title: Los Angeles 2018 data for ensembleDownscaleR case study.

description: Overview

These four datasets are from a spatial region overlapping the Los Angeles metropolitan area ranging from -120.50 to -115.75 longitude, and from 32.00 to 35.70 latitude, and a temporal range of January 1st, 2018, to December 31st, 2018. This region contained 60 monitoring stations from the Air Quality System that provide hourly PM2.5 measurements, which we aggregate to daily averages. AOD data were obtained from the multi-angle implementation of atmospheric correction (MAIAC) with a spatial resolution of 1 km. Chemical transport model (CTM) data were obtained from the Community Multiscale Air Quality (CMAQ) model, which provides daily PM2.5 simulations at a 12 km spatial resolution. We spatially linked the AQS monitor, AOD and CTM data using the MAIAC 1 km grid for modeling fitting and prediction. Additional spatial land use and spatio-temporal meteorological covariates are matched to both monitor locations and grid cells. These include elevation, population density, cloud cover, east-west wind velocity, north-south wind velocity, hpbl, shortwave radiation, and humidity at two meters above the ground. 

We include full data dictionaries for each of these four datasets -  monitor_pm25_with_cmaq,monitor_pm25_with_aod, cmaq_for_predictions, and aod_for_predictions.The monitor_pm25_with_cmaq and monitor_pm25_with_aod datasets are com-prised of daily average PM2.5 for all monitors in the study area and days in2018 for which CMAQ CTM and AOD data are available respectively, alongwith relevant covariates and location information. The cmaq_for_predictionsand aod_for_predictions datasets are comprised of CMAQ CTM and AODdata for all 1km x 1km grid squares in the study and all days in 2018 for whichCMAQ CTM and AOD data are available respectively, along with relevant co-variates and location information.

 

Data Dictionary for monitor_pm25_with_cmaq Dataset

This dataset contains monitor-level PM₂.₅ along with CMAQ and other covariates for fitting the CMAQ-based Bayesian downscaler model. Each row is uniquely identified by time_id and space_id, with one row for every day and monitor where PM₂.₅ and CMAQ data are available.

• time_id: Unique identifier for each day in 2018 (integer, 1-365).

• space_id: Unique identifier for monitor location in the study area (integer, 1-60).

• spacetime_id: Unique identifier for what temporal sets should receive different sets of spatial effects (integer, 1).

• pm25: Daily average PM₂.₅ concentration (continuous, µg/m³).

• cmaq: Nearest Community Multiscale Air Quality (CMAQ) chemical transport model daily PM₂.₅ prediction at 12 km spatial resolution (continuous, µg/m³).

• elevation: Elevation from the Terra ASTER Global Digital Elevation Model (GDEM) Version 3 at a resolution of 1 arc second (continuous, meters).

• population: Annual population counts at 30 arc second spatial resolution from Oak Ridge National Laboratory’s LandScan (integer).

• cloud: Nearest daily percent daytime cloud cover at a 5 km resolution from MODIS Level-2 Cloud product (continuous, 0-100).

• v_wind: Nearest average daily eastward wind velocity component with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, m/s).

• u_wind: Nearest average daily northward wind velocity component with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, m/s).

• short_rf: Nearest average daily shortwave radiation frequency with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, W/m²).

• humidity_2m: Nearest average daily specific humidity with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, kg/kg).

• x: Longitude transformed to kilometer space for distance calculations (continuous, km).

• y: Latitude transformed to kilometer space for distance calculations (continuous, km).

• longitude: Longitude (continuous).

• latitude: Latitude (continuous).

 

Data Dictionary for monitor_pm25_with_aod Dataset

This dataset contains monitor-level PM₂.₅ along with MAIA-satellite-collected aerosol optical depth (AOD) and other covariates for fitting the AOD-based Bayesian downscaler model. Each row is uniquely identified by time_id and space_id, with one row for every day and monitor where PM₂.₅ and AOD data are available.

• time_id: Unique identifier for each day in 2018 (integer, 1-365).

• space_id: Unique identifier for monitor location in the study area (integer, 1-60).

• spacetime_id: Unique identifier for what temporal sets should receive different sets of spatial effects (integer, 1).

• pm25: Daily average PM₂.₅ concentration (continuous, µg/m³).

• aod: Nearest daily 1 km × 1 km aerosol optical depth reading collected at 550 nm from the Terra satellite (overpass at 10:30 a.m. local time), obtained from NASA EOSDIS Land Processes Distributed Active Archive Center (continuous).

• elevation: Elevation from the Terra ASTER Global Digital Elevation Model (GDEM) Version 3 at a resolution of 1 arc second (continuous, meters).

• population: Annual population counts at 30 arc second spatial resolution from Oak Ridge National Laboratory’s LandScan (integer).

• cloud: Nearest daily percent daytime cloud cover at a 5 km resolution from MODIS Level-2 Cloud product (continuous, 0-100).

• v_wind: Nearest average daily eastward wind velocity component with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, m/s).

• u_wind: Nearest average daily northward wind velocity component with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, m/s).

• short_rf: Nearest average daily shortwave radiation frequency with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, W/m²).

• humidity_2m: Nearest average daily specific humidity with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, kg/kg).

• x: Longitude transformed to kilometer space for distance calculations (continuous, km).

• y: Latitude transformed to kilometer space for distance calculations (continuous, km).

• longitude: Longitude (continuous).

• latitude: Latitude (continuous).

 

Data Dictionary for cmaq_for_predictions Dataset

This dataset contains CMAQ and other covariates for generating PM₂.₅ predictions from the CMAQ-based Bayesian downscaler model. Each row is uniquely identified by time_id and space_id, with one row for every day and 1 km × 1 km grid square in the study area.

• time_id: Unique identifier for each day in 2018 (integer, 1-365).

• space_id: Unique identifier for each prediction grid cell in the study area (integers, 1-122,735)

• spacetime_id: Unique identifier for what temporal sets should receive different sets of spatial effects (integer, 1).

• pm25: Daily average PM₂.₅ concentration (continuous, µg/m³).

• cmaq: Nearest Community Multiscale Air Quality (CMAQ) chemical transport model daily PM₂.₅ prediction at 12 km spatial resolution (continuous, µg/m³).

• elevation: Elevation from the Terra ASTER Global Digital Elevation Model (GDEM) Version 3 at a resolution of 1 arc second (continuous, meters).

• population: Annual population counts at 30 arc second spatial resolution from Oak Ridge National Laboratory’s LandScan (integer).

• cloud: Nearest daily percent daytime cloud cover at a 5 km resolution from MODIS Level-2 Cloud product (continuous, 0-100).

• v_wind: Nearest average daily eastward wind velocity component with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, m/s).

• u_wind: Nearest average daily northward wind velocity component with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, m/s).

• short_rf: Nearest average daily shortwave radiation frequency with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, W/m²).

• humidity_2m: Nearest average daily specific humidity with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, kg/kg).

• x: Longitude transformed to kilometer space for distance calculations (continuous, km).

• y: Latitude transformed to kilometer space for distance calculations (continuous, km).

• longitude: Longitude (continuous).

• latitude: Latitude (continuous).

 

Data Dictionary for aod_for_predictions Dataset

This dataset contains AOD and other covariates for generating PM₂.₅ predictions from the AOD-based Bayesian downscaler model. Each row is uniquely identified by time_id and space_id, with one row for every day and 1 km × 1 km grid square in the study area for which AOD is available.

• time_id: Unique identifier for each day in 2018 (integer, 1-365).

• space_id: Unique identifier for each prediction grid cell in the study area (integers, 1-121,892)

• spacetime_id: Unique identifier for what temporal sets should receive different sets of spatial effects (integer, 1).

• aod: Daily 1 km × 1 km aerosol optical depth reading collected at 550 nm from the Terra satellite (overpass at 10:30 a.m. local time), obtained from NASA EOSDIS Land Processes Distributed Active Archive Center (continuous).

• elevation: Elevation from the Terra ASTER Global Digital Elevation Model (GDEM) Version 3 at a resolution of 1 arc second (continuous, meters).

• population: Annual population counts at 30 arc second spatial resolution from Oak Ridge National Laboratory’s LandScan (integer).

• cloud: Nearest daily percent daytime cloud cover at a 5 km resolution from MODIS Level-2 Cloud product (continuous, 0-100).

• v_wind: Nearest average daily eastward wind velocity component with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, m/s).

• u_wind: Nearest average daily northward wind velocity component with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, m/s).

• short_rf: Nearest average daily shortwave radiation frequency with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, W/m²).

• humidity_2m: Nearest average daily specific humidity with a spatial resolution of 0.125° × 0.125°, obtained from the North American Land Data Assimilation System phase 2 (continuous, kg/kg).

• x: Longitude transformed to kilometer space for distance calculations (continuous, km).

• y: Latitude transformed to kilometer space for distance calculations (continuous, km).

• longitude: Longitude (continuous).

• latitude: Latitude (continuous).