17:15 〜 18:30
[ACG36-P02] The field campaign of DRAGON/J-ALPS in the mountain area of Japan for validation of satellite data
NASA/AERONET (Aerosol Robotics Network) field campaign named DRAGON/J-ALPS (Distributed Regional Aerosol Gridded Observation Networks/Joint work to the AerosoL Properties and process Simulations) have been carried out since the spring of 2020 in mainly Nagano prefecture. One of the objectives of the campaign is understanding the spatial distribution of aerosol properties both horizontally and vertically in the mountainous environments. A dense sun photometer network help us understand the spatial distribution both horizontally and vertically to be able to assess the limits of satellite and model retrievals of aerosol properties, especially under varying conditions that would be encountered in mountainous environments. It is of interest to mention that the Japanese missions GCOM-C is equipped with high resolution sensors as SGLI.
The effect of topography on aerosol concentration in the atmosphere motivated our ground observations. In addition to AERONET sun photometer network, we conducted ground observations using portable sun photometers, a PM2.5 measuring instrument, and a ceilometer in the Ina basin, which is surrounded by high mountains in March 2020. The Microtops-2 portable sun photometer is easy to carry and adds mobility to our observations. These Microtops-2 photometers were calibrated with a standard AERONET-Cimel radiometer. The P-Sensor PM2.5 measuring instrument operates via the light scattering method and is developed by the Nagoya University and Panasonic Corporation. This instrument is small enough to be portable. Additionally, we used the compact and lightweight Vaisala ceilometer CL31, which can be used for detection of cloud-base height and vertical visibility measurements.
The values of aerosol optical depth (AOD) at J-ALPS sites tend to be lower than the values of AOD at AERONET site on the Sea of Japan and the PM2.5 concentration levels around J-ALPS sites are usually not too high. It is one of the possible reason that aerosol advection may had been blocked by the high mountains. However, there are days when the concentration becomes high. The morning of March 19, 2020 showed higher than usual concentrations of PM2.5. Also, The Microtops-2 instrument detected a high AOD. These features were consistent with the ceilometer measurements. Notably, the ceilometer also measured the vertical distribution of the atmospheric aerosols. One of the factors is the contribution of local sources. On the time when the concentration was high, visual observation confirmed very high emission from a factory near the observation site. The meteorological conditions are another factor that increases the concentration. On the high concentration day, when the boundary layer squeezes, the atmospheric environment tends to stabilize, which is conducive to the formation of aerosol.
The Japanese satellite GCOM-C was launched on December 23, 2017 and mounted with only the SGLI multispectral sensor, which contains 19 channels encompassing near-UV (380 nm) and violet (412 nm) wavelengths, and two polarization channels PL1 and PL2 in red (674 nm) and near-IR (869 nm) wavelengths. The instantaneous field-of-view (IFOV) of the SGLI is extremely fine, i.e., 250 m from near UV to short IR wavelength range, and 1km for polarization measurements. It is worth noting that fine resolution images from SGLI are available to validate the ground-based measurements, and vice versa. This work reports on the field campaign and comparison of observed AOD and satellite derived AOD.
The effect of topography on aerosol concentration in the atmosphere motivated our ground observations. In addition to AERONET sun photometer network, we conducted ground observations using portable sun photometers, a PM2.5 measuring instrument, and a ceilometer in the Ina basin, which is surrounded by high mountains in March 2020. The Microtops-2 portable sun photometer is easy to carry and adds mobility to our observations. These Microtops-2 photometers were calibrated with a standard AERONET-Cimel radiometer. The P-Sensor PM2.5 measuring instrument operates via the light scattering method and is developed by the Nagoya University and Panasonic Corporation. This instrument is small enough to be portable. Additionally, we used the compact and lightweight Vaisala ceilometer CL31, which can be used for detection of cloud-base height and vertical visibility measurements.
The values of aerosol optical depth (AOD) at J-ALPS sites tend to be lower than the values of AOD at AERONET site on the Sea of Japan and the PM2.5 concentration levels around J-ALPS sites are usually not too high. It is one of the possible reason that aerosol advection may had been blocked by the high mountains. However, there are days when the concentration becomes high. The morning of March 19, 2020 showed higher than usual concentrations of PM2.5. Also, The Microtops-2 instrument detected a high AOD. These features were consistent with the ceilometer measurements. Notably, the ceilometer also measured the vertical distribution of the atmospheric aerosols. One of the factors is the contribution of local sources. On the time when the concentration was high, visual observation confirmed very high emission from a factory near the observation site. The meteorological conditions are another factor that increases the concentration. On the high concentration day, when the boundary layer squeezes, the atmospheric environment tends to stabilize, which is conducive to the formation of aerosol.
The Japanese satellite GCOM-C was launched on December 23, 2017 and mounted with only the SGLI multispectral sensor, which contains 19 channels encompassing near-UV (380 nm) and violet (412 nm) wavelengths, and two polarization channels PL1 and PL2 in red (674 nm) and near-IR (869 nm) wavelengths. The instantaneous field-of-view (IFOV) of the SGLI is extremely fine, i.e., 250 m from near UV to short IR wavelength range, and 1km for polarization measurements. It is worth noting that fine resolution images from SGLI are available to validate the ground-based measurements, and vice versa. This work reports on the field campaign and comparison of observed AOD and satellite derived AOD.