Aerosol optical depth

In this paper, we present an in-house flexible and portable lidar system integrating an inexpensive, passively Q-switched laser Nd: YAG and a detection module operating in both analog and photon counting mode. This system is designed to study the atmospheric boundary layer (BL) and cirrus clouds (CC). The passively Q-switched Nd:YAG pulsed laser, operating at a second-harmonic generation (SHG) wavelength of 532 nm, features a pulse energy up to 200 mJ, a repetition rate of 1 Hz to 15 Hz, and a pulse duration of 15 ns.

14p dianmotminh02 03-05-2024 5 1   Download

This study investigates the relationship between AOD variation and different land use/land cover (LULC) types. These LULC types were first classified from Landsat 9 images using the maximum likelihood classification (MLC) method. The AOD variation for each LULC type acquired from MODIS imagery was then extracted using the mask method.

12p viengels 25-08-2023 4 3   Download

Nghiên cứu này nhằm đánh giá nồng độ bụi mịn PM2.5 tại thành phố Hồ Chí Minh vào năm 2021. Nồng độ PM2.5 trên toàn thành phố cũng được nội suy dựa vào phương pháp nội suy IDW (Inverse Distance Weighting) và Kriging. Ngoài ra, giá trị độ dày quang học sol khí (AOD - Aerosol Optical Depth) trên toàn thành phố Hồ Chí Minh cũng được sử dụng nhằm so sánh với sự phân bố nồng độ PM2.5 nội suy từ phương pháp IDW và Kriging.

10p kimphuong17 01-08-2023 15 3   Download

PM2.5 refers to particulate matter (PM) with a diameter of smaller than 2.5 micrometers flying in the atmosphere. The high concentration of PM2.5 seriously affects the health of people and animals. Using Aerosol Optical Depth (AOD) index achieved from satellite images is possible to estimate and monitor the variation of PM2.5. This study observes the variation of AOD and the maximum PM2.5 concentration over three sub-regions in northern Vietnam based on the daily MODIS aerosol product and PM2.5 measured at a ground station.

4p viwinter2711 05-10-2021 15 1   Download

The paper presents the research to simulate air quality from PM2.5 indicator determined by satellite data. The relationship between ground-based station data and Aerosol Optical Depth (AOD) imagery from Moderate Resolution Imaging Spectroradiometer (MODIS) was examined to establish a regression equation for mapping PM2.5 distribution in Ho Chi Minh city (HCMC).

4p viwinter2711 05-10-2021 8 1   Download

Although a number of studies have extensively inter-compared the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-based aerosol optical depth (AOD) with the Aerosol Robotic Network (AERONET) ground-based AOD on both global and regional scales, almost no similar studies have been conducted for Viet Nam - a humid subtropical climate region. For the first time, inter-comparison between the MODIS Terra and Aqua Collection 6.1 (C6.

9p angicungduoc5 13-06-2020 11 1   Download

In this paper, the optical depths, scattering coefficient, absorption coefficient, extinction coefficient and single scattering albedo were modeled using Optical Properties of Aerosols and Clouds (OPAC) by slightly altering the number densities of water soluble at spectral range of 0.25 – 1.00 µm for eight different relative humidities (RHs) (0, 50, 70, 80, 90, 95, 98 and 99 %). The data was used to calculate the radiative forcing (RF).

12p kien098 16-10-2019 26 0   Download