You are here

AirMSPI – Airborne Multi-angle SpectroPolarimeter Imager

Thursday, August 29, 2019

AirMSPI just completed deployment in the FIREX-AQ/ER2 field campaign flying on the NASA ER-2 high-altitude research aircraft. A total of 12 flights occurred between 1 August and 21 August over fire and smoke targets in Oregon, Washington, Idaho, Montana, California, Utah, and Arizona, as well as the Railroad Valley calibration site in Nevada. A number of these flights were coincident with the NASA DC-8 aircraft and a NOAA Twin Otter aircraft that flew sampling missions into the smoke. Other objectives were coordination with NASA and NOAA satellite overpasses and overflights of ground-based sampling sites.

On 16 August, AirMSPI acquired images of pyrocumulus clouds over the smoke from the Sheridan Fire in Arizona that to date has burned over 13,000 acres in central Arizona near the city of Prescott. The three AirMSPI quicklook images show the smoke and clouds in both intensity and polarized light. The left image shows the scene as it would appear to the human eye, with the brown smoke to the top of the image and white clouds forming over the smoke to the bottom of the image. The middle image incorporates the near infrared band, which can see through some of the smoke to the fire below, which appears as bright red. The right image shows the degree of linear polarization (DoLP) of light in the three polarized AirMSPI spectral bands in the blue, red, and near infrared. In this case the smoke appears greenish-yellow because the small particles in the smoke highly polarize the scattered sunlight. The larger liquid water particles in the cloud do not polarize the scattered light very much in this viewing geometry, so the cloud appears black. AirMSPI’s multi-angle views can also be used to reconstruct the vertical structure of the smoke and the cloud using stereophotogrammetric techniques.

AirMSPI images from the Sheridan Fire in Arizona on 16 August.
(Left) True color (red-green-blue) image
(Middle) Enhanced color (near ir-green-blue) image
(Right) Degree of linear polarization in near ir-green-blue