5:15 PM - 6:30 PM
[ACG36-P03] Advantages of GCOM-C/SGLI for characterization of biomass burning aerosols
The wild fires has increased owing to global warming and climate change, thereby large-scale forest fires have occurred worldwide since 2019. The 5th IPCC report mentions the warming effect of black carbon aerosols as opposed to the cooling effect of other aerosol types (https://www.ipcc.ch/report/ar5/wg1/). Accurate detection of aerosol types has become critical for understanding global climate problems. Carbonaceous aerosols such as smoke, soot, and black/brown carbon should be rigorously defined though, the carbonaceous aerosols generated by wild fires are collectively referred to as biomass burning aerosols (BBAs) hereinafter.
The Japanese mission JAXA/GCOM (Global Change Observation Mission-Climate)-C (SHIKISAI in Japanese) launched in 2017 loads only the second generation global imager. The SGLI (Second generation GLobal Imager) is a multispectral sensor including near-UV and two polarization channels. It contains 19 channels from near-UV to thermal IR, including red (674 nm named PL1 band) and near-IR (869 nm; PL2 band) polarization channels. This study demonstrates the advantages of the SGLI feature in the detection and characterization of BBAs in wildfire events. It has been shown previously that the ratio of near-UV data at 412 to that at 380 nm, named absorption aerosol index (AAI), revealed absorbing aerosols such as BBAs or dust. Figure 1 presents the AAI distribution from SGLI measurements over Kalimantan, Indonesia on Sept.15, 2019, when severe wild fires have happened. The values of AAI greater equal 0.83 indicates BBA type aerosols.
Furthermore, in order to demonstrate such advantage of SGLI that has observation channels in the short wavelength, color composite images are shown in Figure 2. The left image is compiled from JMA/Himawari-8/AHI observations in terms of usual (R, G, B) channels, and the right from SGLI data using shorter (443, 412, 380nm) channels for three primary color than usual. It is clear that the dark yellow color spreading in the center of the figure clearly visualizes the smoke due to biomass burning events according that three primary colors are shifted to shorter wavelengths than usual.
Polarization measurements by SGLI is useful for retrieval of BBAs. Figure 3 provides the distribution of the retrieved aerosol optical thickness (AOT) and measurements at Palang Karaya NASA/AERONET station on 15 September, 2019 in the left and right, respectively.
The Japanese mission JAXA/GCOM (Global Change Observation Mission-Climate)-C (SHIKISAI in Japanese) launched in 2017 loads only the second generation global imager. The SGLI (Second generation GLobal Imager) is a multispectral sensor including near-UV and two polarization channels. It contains 19 channels from near-UV to thermal IR, including red (674 nm named PL1 band) and near-IR (869 nm; PL2 band) polarization channels. This study demonstrates the advantages of the SGLI feature in the detection and characterization of BBAs in wildfire events. It has been shown previously that the ratio of near-UV data at 412 to that at 380 nm, named absorption aerosol index (AAI), revealed absorbing aerosols such as BBAs or dust. Figure 1 presents the AAI distribution from SGLI measurements over Kalimantan, Indonesia on Sept.15, 2019, when severe wild fires have happened. The values of AAI greater equal 0.83 indicates BBA type aerosols.
Furthermore, in order to demonstrate such advantage of SGLI that has observation channels in the short wavelength, color composite images are shown in Figure 2. The left image is compiled from JMA/Himawari-8/AHI observations in terms of usual (R, G, B) channels, and the right from SGLI data using shorter (443, 412, 380nm) channels for three primary color than usual. It is clear that the dark yellow color spreading in the center of the figure clearly visualizes the smoke due to biomass burning events according that three primary colors are shifted to shorter wavelengths than usual.
Polarization measurements by SGLI is useful for retrieval of BBAs. Figure 3 provides the distribution of the retrieved aerosol optical thickness (AOT) and measurements at Palang Karaya NASA/AERONET station on 15 September, 2019 in the left and right, respectively.