Observed and modeled changes in boundary-layer and surface-level actinic flux due to wildfire smoke plumes in the California Central Valley in summer 2018
Data files
Mar 07, 2026 version files 692.95 KB
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corwin_et_al_downwelling_actinic_flux_wecan_harp_tuv_data.csv
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README.md
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Abstract
Wildfire smoke is increasingly degrading air quality across the U.S. via the emission and transport of pollutants. Smoke’s direct role as a pollutant is well-documented; however, smoke also affects pollutant concentration indirectly by changing the shortwave actinic flux necessary for photochemical reactions. We compute smoke-driven changes in surface-level and boundary-layer downwelling actinic flux (F↓) at 550 nm and 380 nm (NO2 photolysis peak) along a 2018 Western wildfire experiment for Cloud chemistry, Aerosol absorption, and Nitrogen (WE-CAN) research flight through the California Central Valley. The onboard HIAPER Airborne Radiation Package (HARP)–Actinic Flux instrument measured F↓. To assess changes in F↓ relative to smoke-free conditions and at altitudes not sampled by the aircraft, we calculate F↓ under assumed background and observed smoke conditions using the U.S. National Science Foundation (NSF) National Center for Atmospheric Research (NCAR) Tropospheric Ultraviolet and Visible (TUV) radiation model. Under smoke-impacted conditions, modeled F↓ minorly underestimates HARP observations; the average modeled-to-measured ratio is 0.93 at 550 nm and 0.89 at 380 nm. Relative to modeled background conditions, observed (modeled) smoke-impacted F↓ at 380 nm decreased by 24% (38%), 15% (24%), and 8% (18%) at 0-0.5 km, 0.5-1 km, and 1-1.5 km, respectively. At the ground, smoke decreased modeled F↓ at 380 nm by 43%—likely an upper bound, as the modeled values slightly underestimate observations. As wildfire seasons grow more severe with climate change, understanding smoke’s combined impact on actinic flux and concentrations of VOCs and nitrogen species is essential for constraining future air quality.
This dataset is used to generate the analysis and figure in the article "Observed and Modeled Changes in Boundary-Layer and Surface-Level Actinic Flux due to Wildfire Smoke Plumes in the California Central Valley in Summer 2018" submitted to the Journal of Geophysical Research: Atmospheres by Corwin et al. This dataset includes the downwelling actinic flux values measured by HARP during WE-CAN's RF08 and modeled using TUV under the model configurations specified in Corwin et al.
Description of the Data:
File name: corwin_et_al_downwelling_actinic_flux_wecan_harp_tuv_data.csv
File type:
Tabular data in a comma-separated CSV format
Missing data:
No columns contain missing data
Abbreviations:
AOD - Aerosol optical depth
HIAPER - High Performance Instrumented Airborne Platform for Environmental Research
HARP - HIAPER Airborne Radiation Package (HARP)Actinic Flux instrument
RF08 - Research flight 08 on August 8, 2018
WE-CAN - Western wildfire experiment for Cloud chemistry, Aerosol absorption, and Nitrogen
Column Headers - Description:
location_id - Identifier for sample location along the flight path
latitude - Latitude
longitude - Longitude
altitude_asl - Altitude of the aircraft above sea-level
utc_datetime - Date and time in UTC
harp_zenith_380 - Downwelling actinic flux at 380 nm measured by the HARP instrument
harp_zenith_550 - Downwelling actinic flux at 550 nm measured by the HARP instrument
aircraft_smoke_380 - Downwelling actinic flux at 380 nm modeled by TUV using the aircraft-smoke model configuration
aircraft_smoke_550 - Downwelling actinic flux at 550 nm modeled by TUV using the aircraft-smoke model configuration
aircraft_background_380 - Downwelling actinic flux at 380 nm modeled by TUV using the aircraft-background model configuration
aircraft_background_550 - Downwelling actinic flux at 550 nm modeled by TUV using the aircraft-background model configuration
ground_smoke_380 - Downwelling actinic flux at 380 nm modeled by TUV using the ground-smoke model configuration
ground_smoke_550 - Downwelling actinic flux at 550 nm modeled by TUV using the ground-smoke model configuration
ground_background_380 - Downwelling actinic flux at 380 nm modeled by TUV using the ground-background model configuration
ground_background_550 - Downwelling actinic flux at 550 nm modeled by TUV using the ground-background model configuration
Underlying Data Access Information
The underlying data from the WE-CAN aircraft campaign are publicly available at https://data.eol.ucar.edu/master_lists/generated/we-can/.