Aerosol optical depth, aerosol composition and air pollution during summer and winter conditions in budapest october 2007 science of the total environment 383. Preliminary investigations toward nighttime aerosol. Pdf aerosol optical depth measurements in eastern china. Studies have found correlations between satellite aerosol optical depth aod and pm2. Longterm groundbased measurements of aerosol optical depth. View, download, or analyze more of these data from nasa earth observations neo.
Pdf retrieval of aerosol optical depth in the arid or. The product is useful proxy for air pollution and can be used in monitoring and forecasting air quality. Aod tells us how much direct sunlight is prevented from reaching the ground by these aerosol particles. Reid2 1department of atmospheric sciences, university of north dakota, grand forks, nd 2marine meteorology division, naval research laboratory, monterey, ca. To help satellite retrieval of aerosols and studies of their radiative effects, we demonstrate that daytime 532 nm aerosol optical depth over lowlevel clouds is similar to that in neighboring clear skies at the same heights in recent airborne lidar and sunphotometer observations above the southeast atlantic. Aerosol optical thickness is the degree to which aerosols prevent the transmission of light in the atmoshpere. Improved estimation of aerosol optical depth from modis. View the fgdc metatdata for aerosol optical thickness 1 month terramodis quick tip. Aerosol optical depth aod is the measure of aerosols e. Pdf the dependence of aerosol optical depth aod on air particulate concentrations in the mixing layer height mlh was studied in budapest in july. Aerosol optical depth trends over different regions of india s. Assessment of the aerosol optical depths measured by satellite.
Chang1, xuefei hu 2and yang liu there has been a growing interest in the use of satelliteretrieved aerosol optical depth aod to estimate ambient concentrations of pm 2. Aerosol optical depth measurements in eastern china and a new calibration method. Esrl global monitoring laboratory global radiation and. Validation of aerosol optical depth 6 figure 1 displays the frequency map of modis aerosol retrievals over land as derived using the level3 daily aerosol products from july to september 2000. In the frame of the caliope project baldasano et al. As a fundamental optical property of aerosols, aerosol optical depth aod. Several satellite aerosol optical depth aod prod ucts are assessed in terms of their data quality in the alberta oil sands region. Aerosol optical depth michigan technological university.
The resulting total optical depth can be partitioned into effects from ozone, water vapor, molecular rayleigh scattering and aerosol effects. Aerosol optical depth the aerosol optical depth was calculated for the seven channels of the uvmfr for the 6month period in 1999 when the instrument was deployed at the black mountain site. Ramachandran, sumita kedia, rohit srivastava space and atmospheric sciences division, physical research laboratory, navrangpura, ahmedabad, gujarat 380009, india article info article history. Absorption aerosol optical depth components from aeronet. Superimposed are the locations of the aeronet sites included in this validation. Estimates of global multicomponent aerosol optical depth. Total optical depth retrievals are possible if the remaining parameters are measured or known. Intercomparison between satellitederived aerosol optical thickness and pm 2. Solar lights model 540 microtops ii sunphotometer is a light weight, portable 5 channel instrument for measuring aerosol optical thickness, direct solar irradiance, and water vapor column easily, accurately and dependably. Aerosol optical depth aod measures become very important for cpv and csp. G eogdzhayev,e paul ginoux,b michael herzog,a akiko higurashi,f dorothy koch,e christine land,d. The aim of this work was to use the merra2 reanalysis to study urban air pollution at a national scale by analyzing the aod. To help them in their studies, scientists use satellites to map where there were large amounts of aerosol on a given day, or over a span of days.
The most important of these is the aerosol optical depth aod, which is a. In astronomy, the photosphere of a star is defined as the surface where its optical depth is 23. Aerosol optical depth as a measure of particulate exposure. This work quantifies the added value of including aci in an online coupled climatechemistry model wrfchem, 0. Nine years of uv aerosol optical depth measurements at. There are also many applications for aerosol optical depth aod data. For this, aerosol simulations from the georgia techgoddard global ozone chemistry aerosol radiation and transport gocart model chin et al. Aerosol optical depth is a measure of the extinction of the solar beam by dust and haze. Pdf aerosol optical depth, aerosol composition and air. The product is more accurate over water surfaces than over land surfaces. Aher5 1 department of atmospheric and space sciences, university of pune 07 2 nasa goddard space flight center greenbelt, md 20771, usa 3 universities space research association, greenbelt, md 20771, usa. This means that each photon emitted at the photosphere suffers an average of less than one scattering before it reaches the observer. Controlling factors analysis for the himawari8 aerosol. Exploring aerosol optical thickness using modis satellite.
Numerous studies have found adverse health effects of acute and chronic exposure to fine particulate matter pm2. Suspended matteraerosol optical depth and aerosol size parameter aerosol product application team of the awg aerosolsair qualityatmospheric chemistry team. Microtops ii sunphotometer, aerosol optical thickness. Aerosol optical depth impact of chemical fire accident on spectral solar irradiance over urban environmenta case study k. Retrieval of aerosol optical depth in the arid or semiarid region of northern xinjiang, china article pdf available in remote sensing 102 january 2018 with 235 reads how we measure reads. Received 20 may 2011 received in revised form 4 november 2011 accepted 5 november 2011. Global estimates of ambient fine particulate matter. Validation of modis aerosol optical depth retrievals over a tropical urban site, pune, india sanjay morel, p. Validation of modis aerosol optical depth retrieval over land. Fine mode, coarse mode aerosol optical depth aod and fine mode fraction aerosol optical depth in wet and dry seasons daily and seasonal mean of fine mode aod, coarse mode aod, and fine mode fraction concentrations from 1st march 20 to 31st may 2015 and 1st june. Flow chart of this new algorithm for estimating aerosol optical depth from modis data. Long term measurements by the aeronet program of spectral aerosol optical depth, precipitable water and derived angstrom exponent were analyzed and compiled into an aerosol optical properties climatology.
It pro vides a measure of the columnar aerosol loading and. Aerosol optical thickness 1 month terramodis view by date. A comparison of model and satellitederived aerosol. Calibrating modis aerosol optical depth for predicting daily pm 2. This multispectral instrument is designed to measure direct solar irradiance in five channels of selected wavelengths. In order to answer this question we must return our focus to the sun. Aerosol optical depth measurements and their impact. Aerosol optical depth aerosol optical depth aod is the measure of aerosols e. Trends in aerosol optical depth over indiantrends in aerosol optical depth over indian region. Merra2 aerosol reanalysis is a pioneering tool for investigating air quality issues, noteworthy for its global coverage and its distinction of aerosol speciation expressed in the form of aerosol optical depth aod. Radiation exiting the atmosphere can be approximated as a function of optical depth, scattering phase function and single. Validation of modis aerosol optical depth retrievals over.
The effective radius of the aerosol particles is defined as. The aerosol optical depth aod, which is the integral of the atmospheric extinction coefficient from the surface to the top of the atmosphere. Air pollution epidemiological studies relying on ground measurements provided by monitoring networks are often limited by sparse and unbalanced spatial distribution of the monitors. The distortion caused by this interaction can be estimated with the aid of radiative transfer model and converted into aerosol loading, also known as aerosol optical depth aod, which has shown a strong positive relationship with the pm 2. Calibrating modis aerosol optical depth for predicting. Aerosol optical depth trends over different regions of india.
High aerosol amounts occur over south america from july through september. Annual cycle of global distributions of aerosol optical. Aerosol optical depth quantifies the amount of aerosol in the atmosphere. Dashed lines represent aerosol optical depth equals 0. Aerosol optical depth, physical properties and radiative. Atmosphere free fulltext aerosol optical depth of the. High aerosol amounts are linked to different process in different places and times of year. Pdf importance of aerosol optical depth in the atmospheric. Aerosol optical depth valueadded product arm atmospheric. Spatial analysis of modis aerosol optical depth, pm 2. Quality assured monthly means are presented and described for nine primary sites and twentyone additional multiyear sites. At the temperature at optical depth 23, the energy emitted by the star the original derivation is for the sun matches the observed total energy emitted. Retrieval of optical depth for heavy smoke aerosol plumes.
Trends in aerosol optical depth over indiantrends in. The current study focused on athens, greece during the year of 2004 and 1 demonstrates a systemized process for aligning data obtained from satellite aerosol optical depth aod with geographic location and time, 2 evaluates the ability to apply imputation methods to censored data, and 3 explores whether aod data can be used. A longterm historical aerosol optical depth data record. Aerosol optical depth and the global brewer network. Langley plot analysis was employed to obtain a v0 value specific to each wavelength channel using the objective algorithm of harrison and michalsky. Pdf atmospheric aerosols being an important component of the atmosphere play an important role in global and regional climate change. Aerosol optical depth aod is the height integral of the aerosol extinction coefficient. Backtrajectory analyses show an additional dependence of the aerosol optical depth on the origin of the air masses.
1545 1338 794 1413 78 978 407 167 558 454 1567 334 929 247 896 738 1517 1363 951 429 1278 733 4 609 500 13 1155 1427 1547 197 3 1476 997 1110 532 447 1142 1150 1212 706 28