Influences of the window size of moderate resolution imaging spectroradiometer (MODIS) aerosol optical thickness (AOT) values on particulate matter (PM10) motoring in Klang Valley, Malaysia

2012 ◽  
Vol 7 (12) ◽  
Author(s):  
Jamil Amanollahi
Keyword(s):  
Particulate Matter ◽  
Optical Thickness ◽  
Window Size ◽  
Aerosol Optical Thickness ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Klang Valley ◽  
Moderate Resolution Imaging Spectroradiometer

scholarly journals Forecasting Carbon Monoxide on a Global Scale for the ATom-1 Aircraft Mission: Insights from Airborne and Satellite Observations and Modeling

2018 ◽  
Author(s):  
Sarah A. Strode ◽  
Junhua Liu ◽  
Leslie Lait ◽  
Róisín Commane ◽  
Bruce Daube ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Optical Thickness ◽  
Global Scale ◽  
Satellite Observations ◽  
Aerosol Optical Thickness ◽  
Large Contribution ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Typical Summer

Abstract. GEOS-5 forecasts and analyses show considerable skill in predicting and simulating the CO distribution and the timing of CO enhancements observed during the ATom-1 aircraft mission. Using tagged tracers for CO, we find a dominant contribution from non-biomass burning sources along the ATom transects except over the tropical Atlantic, where African biomass burning makes a large contribution to the CO concentration. One of the goals of ATom is to provide a chemical climatology over the oceans, so it is important to consider whether August 2016 was representative of typical summer conditions. Using satellite observations of 700 hPa and column CO from the Measurement of Pollution in the Troposphere (MOPITT) instrument, 215 hPa CO from the Microwave Limb Sounder (MLS), and aerosol optical thickness from the Moderate Resolution Imaging Spectroradiometer (MODIS), we find that CO concentrations and aerosol optical thickness in August 2016 were within the observed range of the satellite observations, but below the decadal median for many of the regions sampled. This suggests that the ATom-1 measurements may represent relatively clean but not exceptional conditions for lower tropospheric CO.

scholarly journals Implications of satellite swath width on global aerosol optical thickness statistics

2012 ◽  
Vol 5 (2) ◽  
pp. 2795-2820 ◽  
Author(s):  
P. R. Colarco ◽  
L. A. Remer ◽  
R. A. Kahn ◽  
R. C. Levy ◽  
E. J. Welton
Keyword(s):  
Optical Thickness ◽  
Aerosol Optical Thickness ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Moderate Resolution ◽  
Direct Forcing ◽  
Resolution Imaging ◽  
Sun Photometer ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Impact

Abstract. We assess the impact of swath width on the statistics of aerosol optical thickness (AOT) retrieved by satellite, as inferred from observations made by the Moderate Resolution Imaging Spectroradiometer (MODIS). Using collocated AERONET sun photometer observations we develop a correction to the MODIS data to account for calibration and algorithmic view angle dependency in the retrieved AOT. We sub-sample and correct the AOT data from the MODIS Aqua instrument along several candidate swaths of various widths for the years 2003–2011. We find that over ocean the global, annual mean AOT is within ± 0.01 of the full swath AOT for all of our sub-samples. Over land, however, most of our sub-samples are outside of this criterion range in the global, annual mean. Moreover, at smaller spatial and temporal scales we find wide deviation in the sub-sample AOT relative to the full swath over both land and ocean. In all, the sub-sample AOT is within ± 0.01 of the full swath value less than 25% of the time over land, and less than 50% of the time over ocean (less than 35% for all but the widest of our sub-sample swaths). These results suggest that future aerosol satellite missions having only narrow swath views may not sample the true AOT distribution sufficiently to reduce significantly the uncertainty in aerosol direct forcing of climate.

scholarly journals Estudio de la dinámica del espesor óptico de los aerosoles en Perú y América del Sur a partir de las imágenes MODIS de los satélites TERRA y AQUA en el periodo 2000-2013

2015 ◽  
Vol 18 (1) ◽  
pp. 1-20
Author(s):  
Noelia Rojas Benavente ◽  
Joel Rojas Acuña
Keyword(s):  
Optical Thickness ◽  
Aerosol Optical Thickness ◽  
La Paz ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
América Del Sur

El objetivo de este trabajo es estudiar la dinámica de los aerosoles en el Perú y América del Sur entre las latitudes 4°N-24°S y las longitudes 83°W-33°W, a partir de las imágenes de los promedios mensuales del espesor óptico de los aerosoles, Aerosol Optical Thickness, AOT, en la longitud de onda de 550 nm medidos por el sensor MODIS, Moderate Resolution Imaging Spectroradiometer, a bordo de los satélites TERRA y AQUA, para un periodo de catorce años, del 2000 al 2013. Se han usado los datos AOT in-situ en los horarios de 6 estaciones AERONET de América del Sur que incluyen cuatro de Brasil, tales como, Rio Branco, Paraná Ji, Alta Foresta y Campo Grande; uno de Chile, la estación de Arica y uno de Bolivia, la estación de La Paz; además incorporamos 166 datos imágenes AOT-MODIS-TERRA de los productos mensuales obtenidos para un periodo del 2000 al 2013 y 138 datos imágenes AOT-MODIS-AQUA de los productos mensuales obtenidos para un periodo del 2002 al 2013 estimados a partir de la herramienta de visulaización y análisis vía Web Giovanni con una resolución de 1°×1°, es decir, de 110 km×110 km. La serie de tiempos AOT-MODIS-TERRA tienen valores máximos y mínimos entre 0.0 y 0.499 y sus valores máximos se ubican en la temporada seca del Hemisferio Sur, entre agosto a noviembre, durante los 14 años. La serie de tiempos AOT-MODIS-AQUA tienen valores máximos y mínimos entre 0.0 y 0.493 y sus valores máximos se ubican en la temporada seca, durante los 12 años. La serie de tiempos AOT-AERONET en las cuatro estaciones de Brasil muestra una variación estacional con máximos en la estación seca durante los 14 años, mientras que, en las estaciones de Chile y Bolivia se muestra una variación estacional muy diferente a los datos AOT/MODIS, teniendo pocos registros de datos AOT. Las gráficas de dispersión de las series de tiempo AOT-MODIS vs AOT-AERONET muestran una alta correlación de 0.8 a 0.9 en cuatro estaciones de Brasil y una correlación baja de 0.33 a 0.39 en la estación de Chile y de 0.13 a 0.19 en la estación de Bolivia.

scholarly journals Long-Term Analyses of Aerosol Optical Thickness Using Caliop

2020 ◽  
Vol 237 ◽  
pp. 02023
Author(s):  
Masahiro Fujikawa ◽  
Rei Kudo ◽  
Tomoaki Nishizawa ◽  
Eiji Oikawa ◽  
Akiko Higurashi ◽  
...  
Keyword(s):  
Optical Thickness ◽  
Sea Salt ◽  
Water Soluble ◽  
Aerosol Optical Thickness ◽  
Orthogonal Polarization ◽  
Standard Product ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

We developed an algorithm to derive extinction coefficients for four aerosol components (water-soluble, dust, sea salt, black carbon) from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) data. The algorithm was applied to the nine-year data for 2007–2015 and the results were compared to CALIOP standard product (CALIOP-ST) and MODerate resolution Imaging Spectroradiometer (MODIS) standard product (MODIS-ST). Comparisons of the total aerosol optical thickness (AOT) showed that MODIS-ST was the largest, followed by CALIOP-ST (Ver.4), and our product. CALIOP-ST (Ver.3) showed a similar magnitude to ours.

scholarly journals Reconciling Simulated and Observed Views of Clouds: MODIS, ISCCP, and the Limits of Instrument Simulators

2012 ◽  
Vol 25 (13) ◽  
pp. 4699-4720 ◽  
Author(s):  
Robert Pincus ◽  
Steven Platnick ◽  
Steven A. Ackerman ◽  
Richard S. Hemler ◽  
Robert J. Patrick Hofmann
Keyword(s):  
Optical Thickness ◽  
Model Error ◽  
Diagnostic Tools ◽  
Limited Information ◽  
Global Models ◽  
Cloud Properties ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cloud Top Pressure

Abstract The properties of clouds that may be observed by satellite instruments, such as optical thickness and cloud-top pressure, are only loosely related to the way clouds are represented in models of the atmosphere. One way to bridge this gap is through “instrument simulators,” diagnostic tools that map the model representation to synthetic observations so that differences can be interpreted as model error. But simulators may themselves be restricted by limited information or by internal assumptions. This paper considers the extent to which instrument simulators are able to capture essential differences between the Moderate Resolution Imaging Spectroradiometer (MODIS) and the International Satellite Cloud Climatology Project (ISCCP), two similar but independent estimates of cloud properties. The authors review the measurements and algorithms underlying these two cloud climatologies, introduce a MODIS simulator, and detail datasets developed for comparison with global models using ISCCP and MODIS simulators. In nature MODIS observes less midlevel cloudiness than ISCCP, consistent with the different methods used to determine cloud-top pressure; aspects of this difference are reproduced by the simulators. Differences in observed distributions of optical thickness, however, are not captured. The largest differences can be traced to different approaches to partly cloudy pixels, which MODIS excludes and ISCCP treats as homogeneous. These cover roughly 15% of the planet and account for most of the optically thinnest clouds. Instrument simulators cannot reproduce these differences because there is no way to synthesize partly cloudy pixels. Nonetheless, MODIS and ISCCP observations are consistent for all but the optically thinnest clouds, and models can be robustly evaluated using instrument simulators by integrating over the robust subset of observations.

scholarly journals Global Distribution of Column Satellite Aerosol Optical Depth to Surface PM2.5 Relationships

2020 ◽  
Vol 12 (12) ◽  
pp. 1985 ◽  
Author(s):  
Sundar Christopher ◽  
Pawan Gupta
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Large Population ◽  
Correlation Coefficients ◽  
Large Spread ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Using a combined Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) mid-visible aerosol optical depth (AOD) product at 0.1 × 0.1-degree spatial resolution and collocated surface PM2.5 (particulate matter with aerodynamic diameter smaller than 2.5 μm) monitors, we provide a global five-year (2015–2019) assessment of the spatial and seasonal AOD–PM2.5 relationships of slope, intercepts, and correlation coefficients. Only data from ground monitors accessible through an open air-quality portal that are available to the worldwide community for air quality research and decision making are used in this study. These statistics that are reported 1 × 1-degree resolution are important since satellite AOD is often used in conjunction with spatially limited surface PM2.5 monitors to estimate global distributions of surface particulate matter concentrations. Results indicate that more than 3000 ground monitors are now available for PM2.5 studies. While there is a large spread in correlation coefficients between AOD and PM2.5, globally, averaged over all seasons, the correlation coefficient is 0.55 with a unit AOD producing 54 μgm−3 of PM2.5 (Slope) with an intercept of 8 μgm−3. While the number of surface PM2.5 measurements has increased by a factor of 10 over the last decade, a concerted effort is still needed to continue to increase these monitors in areas that have no surface monitors, especially in large population centers that will further leverage the strengths of satellite data.

scholarly journals Development studies towards an 11-year global gridded aerosol optical thickness reanalysis for climate and applied applications

2015 ◽  
Vol 8 (12) ◽  
pp. 10455-10538 ◽  
Author(s):  
P. Lynch ◽  
J. S. Reid ◽  
D. L. Westphal ◽  
J. Zhang ◽  
T. F. Hogan ◽  
...  
Keyword(s):  
Optical Thickness ◽  
Science Studies ◽  
Weather Prediction ◽  
Aerosol Optical Thickness ◽  
Reanalysis Product ◽  
Optical Propagation ◽  
Coarse Mode ◽  
Model Aerosol ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. While standalone satellite and model aerosol products see wide utilization, there is a significant need in numerous climate and applied applications for a fused product on a regular grid. Aerosol data assimilation is an operational reality at numerous centers, and like meteorological reanalyses, aerosol reanalyses will see significant use in the near future. Here we present a standardized 2003–2013 global 1° × 1° and 6 hourly modal aerosol optical thickness (AOT) reanalysis product. This dataset can be applied to basic and applied earth system science studies of significant aerosol events, aerosol impacts on numerical weather prediction, and electro-optical propagation and sensor performance, among other uses. This paper describes the science of how to develop and score an aerosol reanalysis product. This reanalysis utilizes a modified Navy Aerosol Analysis and Prediction System (NAAPS) at its core and assimilates quality controlled retrievals of AOT from the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua and the Multi-angle Imaging SpectroRadiometer (MISR) on Terra. The aerosol source functions, including dust and smoke, were regionally tuned to obtain the best match between the model fine and coarse mode AOTs and the Aerosol Robotic Network (AERONET) AOTs. Other model processes, including deposition, were tuned to minimize the AOT difference between the model and satellite AOT. Aerosol wet deposition in the tropics is driven with satellite retrieved precipitation, rather than the model field. The final reanalyzed fine and coarse mode AOT at 550 nm is shown to have good agreement with AERONET observations, with global mean root mean square error around 0.1 for both fine and coarse mode AOTs. This paper includes a discussion of issues particular to aerosol reanalyses that make them distinct from standard meteorological reanalyses, considerations for extending such a reanalysis outside of the NASA A-Train era, and examples of how the aerosol reanalysis can be applied or fused with other model or remote sensing products. Finally, the reanalysis is evaluated in comparison with other available studies of aerosol trends, and the implications of this comparison are discussed.

scholarly journals Radiative and Microphysical Properties of Cirrus Cloud Inferred from Infrared Measurements Made by the Moderate Resolution Imaging Spectroradiometer (MODIS). Part I: Retrieval Method

2014 ◽  
Vol 53 (5) ◽  
pp. 1297-1316 ◽  
Author(s):  
Hironobu Iwabuchi ◽  
Soichiro Yamada ◽  
Shuichiro Katagiri ◽  
Ping Yang ◽  
Hajime Okamoto
Keyword(s):  
Brightness Temperature ◽  
Optical Thickness ◽  
Optimal Estimation ◽  
Particle Radius ◽  
Cirrus Cloud ◽  
Microphysical Properties ◽  
Effective Particle ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

AbstractAn optimal estimation–based algorithm is developed to infer the global-scale distribution of cirrus cloud radiative and microphysical properties from the measurements made by the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) at three infrared (IR) window bands centered at 8.5, 11, and 12 μm. Cloud-top and underlying surface temperatures, as a priori information, are obtained from the MODIS operational products. A fast-forward model based on semianalytical equations for the brightness temperature is used. The modeling errors in brightness temperature are mainly from the uncertainties in model parameters including surface emissivity, precipitable water, and cloud-base temperature. The total measurement–model errors are well correlated for the three bands, which are considered in the retrieval. The most important factors for the accurate retrieval of cloud optical thickness and the effective particle radius are cloud-top and surface temperatures, whereas model parameter uncertainties constitute a moderately significant error source. The three-band IR method is suitable for retrieving optical thickness and effective radius for cloud optical thicknesses within a range of 0.5–6, where the typical root-mean-square error is less than 20% in optical thickness and less than 40% in effective particle radius. A tropical-region case study demonstrates the advantages of the method—in particular, the ability to be applied to more pixels in optically thin cirrus in comparison with a solar-reflection-based method—and the ability of the optimal estimation framework to produce useful diagnostics of the retrieval quality. Collocated comparisons with spaceborne active remote sensing data exhibit reasonable consistency with respect to retrieved particle size.

scholarly journals Seven year particulate matter air quality assessment from surface and satellite measurements

2008 ◽  
Vol 8 (1) ◽  
pp. 327-365 ◽  
Author(s):  
P. Gupta ◽  
S. A. Christopher
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Satellite Data ◽  
Satellite Measurements ◽  
Ground Station ◽  
Air Quality Assessment ◽  
Long Time ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. Using seven years of the Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical thickness (AOT) data and ground measurements of particulate matter mass over one site in the Southeastern United States (33.55 N, 86.82 W) we present a comprehensive analysis of various aspects of particulate matter air quality. Monthly, seasonal and inter-annual relationships are examined with emphasis on sampling biases, quality indicators in the AOT product and various cloud clearing criteria. Our results indicate that PM2.5 mass concentration over Northern Birmingham has decreased by about 23% in year 2006 when compared to year 2002 and air quality during summer months are poor when compared to winter months. MODIS-Terra AOT data was available only about 50% of the time due to cloud cover and favorable surface conditions. However, the mean difference in monthly mean PM2.5 was less than 2.2 μgm−3 derived using all the data and from only those days when satellite AOT was available indicating that satellite data does not have sampling issues. The correlation between PM2.5 and MODIS AOT increased from 0.52 to 0.62 when hourly PM2.5 data were used instead of daily mean PM2.5 data. Changing box size for satellite data around the ground station during comparisons produced less than ±0.03 difference in mean AOT values for 90% of observations. Application of AOT quality flags reduced the sample size but does not affect AOT-PM2.5 relationship significantly. We recommend using AOT quality flags for daily analysis, whereas long time scale analysis can be performed without using all AOT retrievals to obtain better sampling. Our analysis indicates that satellite data is a useful tool for monitoring particulate matter air quality especially in regions where ground measurements are not available.

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