Radiative impact of record-breaking wildfires from integrated ground-based data.

Area of Science:

• Atmospheric Science
• Remote Sensing
• Climate Science

Background:

• Traditional wildfire radiative effect estimations rely on models and limited observational data.
• Dense wildfire plumes, especially from intense events, present challenges for accurate radiative impact assessment due to data gaps.

Purpose of the Study:

• To introduce a novel method for assessing wildfire radiative effects using ground-based irradiance and aerosol optical depth (AOD) measurements.
• To quantify the radiative impact of dense plumes from the 2020 Western US wildfires.

Main Methods:

• Utilized ground-based measurements of shortwave and spectrally resolved irradiances.
• Incorporated aerosol optical depth (AOD) data in visible and near-infrared spectral ranges.
• Applied radiative transfer calculations constrained by novel observational data.

Main Results:

• Demonstrated that dense wildfire plumes drastically reduced solar surface irradiance (up to 70%).
• Observed extremely high AOD values (above 10 at 500 nm), obscuring the sun.
• Quantified radiative impacts comparable to major volcanic eruptions and continental clouds.

Conclusions:

• The novel method enhances the assessment of radiative effects from dense wildfire plumes.
• Ground-based irradiance and AOD data provide critical constraints for climate model validation.
• Wildfire smoke poses a significant radiative forcing comparable to other major atmospheric events.