scholarly journals Retrieval of the Fine-Mode Aerosol Optical Depth over East China Using a Grouped Residual Error Sorting (GRES) Method from Multi-Angle and Polarized Satellite Data

2018 ◽  
Vol 10 (11) ◽  
pp. 1838 ◽  
Author(s):  
Yang Zhang ◽  
Zhengqiang Li ◽  
Zhihong Liu ◽  
Juan Zhang ◽  
Lili Qie ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Residual Error ◽  
East China ◽  
Anthropogenic Aerosols ◽  
Aerosol Model ◽  
Retrieval Accuracy ◽  
Aerosol Loading ◽  
Fine Mode ◽  
Fine Mode Aerosol

The fine-mode aerosol optical depth (AODf) is an important parameter for the environment and climate change study, which mainly represents the anthropogenic aerosols component. The Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar (PARASOL) instrument can detect polarized signal from multi-angle observation and the polarized signal mainly comes from the radiation contribution of the fine-mode aerosols, which provides an opportunity to obtain AODf directly. However, the currently operational algorithm of Laboratoire d’Optique Atmosphérique (LOA) has a poor AODf retrieval accuracy over East China on high aerosol loading days. This study focused on solving this issue and proposed a grouped residual error sorting (GRES) method to determine the optimal aerosol model in AODf retrieval using the traditional look-up table (LUT) approach and then the AODf retrieval accuracy over East China was improved. The comparisons between the GRES retrieved and the Aerosol Robotic Network (AERONET) ground-based AODf at Beijing, Xianghe, Taihu and Hong_Kong_PolyU sites produced high correlation coefficients (r) of 0.900, 0.933, 0.957 and 0.968, respectively. The comparisons of the GRES retrieved AODf and PARASOL AODf product with those of the AERONET observations produced a mean absolute error (MAE) of 0.054 versus 0.104 on high aerosol loading days (AERONET mean AODf at 865 nm = 0.283). An application using the GRES method for total AOD (AODt) retrieval also showed a good expandability for multi-angle aerosol retrieval of this method.

scholarly journals Recent increase in aerosol loading over the Australian arid zone

2010 ◽  
Vol 10 (4) ◽  
pp. 1689-1699 ◽  
Author(s):  
R. M. Mitchell ◽  
S. K. Campbell ◽  
Y. Qin
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Arid Zone ◽  
Severe Drought ◽  
Near Surface ◽  
Aerosol Loading ◽  
Ephemeral Lakes ◽  
Fine Mode ◽  
Fine Mode Aerosol ◽  
Ephemeral Vegetation

Abstract. Collocated sun photometer and nephelometer measurements at Tinga Tingana in the Australian Outback over the decade 1997–2007 show a significant increase in aerosol loading following the onset of severe drought conditions in 2002. This increase is confined to the season of dust activity, particularly September to March. In contrast, background aerosol levels during May, June and July remained stable. The enhanced aerosol loadings during the latter 5 years of the study period can be understood as a combination of dune destabilisation through loss of ephemeral vegetation and surface crust, and the changing supply of fluvial sediments to ephemeral lakes and floodplains within the Lake Eyre Basin. Major dust outbreaks are generally highly localised, although significant dust activity was observed at Tinga Tingana on 50% of days when a major event occurred elsewhere in the Lake Eyre Basin, suggesting frequent basin-wide dust mobilisation. Combined analysis of aerosol optical depth and scattering coefficient shows weak correlation between the surface and column aerosol (R2=0.24). The aerosol scale height is broadly distributed with a mode typically between 2–3 km, with clearly defined seasonal variation. Climatological analysis reveals bimodal structure in the annual cycle of aerosol optical depth, with a summer peak related to maximal dust activity, and a spring peak related to lofted fine-mode aerosol. There is evidence for an increase in near-surface aerosol during the period 2003–2007 relative to 1997–2002, consistent with an increase in dust activity. This accords with an independent finding of increasing aerosol loading over the Australian region as a whole, suggesting that rising dust activity over the Lake Eyre Basin may be a significant contributor to changes in the aerosol budget of the continent.

scholarly journals Interannual and seasonal variations in aerosol optical depth of the atmosphere in two regions of Spitsbergen Archipelago (2002–2018)

2020 ◽  
Author(s):  
Dmitry M. Kabanov ◽  
Christoph Ritter ◽  
Sergey M. Sakerin
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Wave Spectrum ◽  
Short Wave ◽  
The Arctic ◽  
Data Set ◽  
Fine Mode ◽  
European Arctic ◽  
Highly Correlated ◽  
Fine Mode Aerosol

Abstract. In this work hourly averaged sun photometer data from the sites Barentsburg and Ny-Ålesund, both located in Spitsbergen in the European Arctic, are compared. Our data set comprises the years 2011 to 2017. We found for more turbid periods (aerosol optical depth τ0.5 > 0.1) that typically Barentsburg is more polluted than Ny-Ålesund, especially in the short wave spectrum. However, the diurnal variation of AOD is highly correlated. Next, τ was divided into a fine and coarse mode. It was found that generally the fine mode aerosol optical depth dominates and also shows a larger interannual as inner annual variation. Tau fine τf is in fact larger in spring during the Arctic Haze period. Overall the aerosol optical depth seems to decrease, although this is not statistically significant.

Retrieval of Fine Mode Aerosol Optical Depth Based on Satellite Polarization Remote Sensing

2020 ◽  
Vol 57 (3) ◽  
pp. 030101
Author(s):  
高迦南 Gao Jianan ◽  
李丽萍 Li Liping ◽  
崔廷伟 Cui Tingwei ◽  
陈晨 Chen Chen
Keyword(s):  
Remote Sensing ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Fine Mode ◽  
Fine Mode Aerosol

scholarly journals Using MODIS and AERONET to Determine GCM Aerosol Size

2006 ◽  
Vol 63 (4) ◽  
pp. 1338-1347 ◽  
Author(s):  
Glen Lesins ◽  
Ulrike Lohmann
Keyword(s):  
Size Distribution ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
General Circulation ◽  
Climate Model ◽  
General Circulation Models ◽  
Aerosol Size Distribution ◽  
Error Source ◽  
Fine Mode ◽  
Fine Mode Aerosol

Abstract Aerosol size is still a poorly constrained quantity in general circulation models (GCMs). By using the modal radii of the coarse and fine mode retrieved from 103 stations in the Aerosol Robotic Network (AERONET) and the fine mode aerosol optical depth fraction derived from both the Moderate Resolute Imaging Spectroradiometer (MODIS) Terra and AERONET, a globally and monthly averaged aerosol size distribution dataset was computed assuming internally mixed aerosols. Different methods were employed in creating the size distribution datasets that were input to the ECHAM4 climate model giving a globally averaged aerosol optical depth (AOD) at 500 nm that ranged from 0.11 to 0.20 depending on the method. This translates into a globally averaged direct aerosol top-of-atmosphere forcing range from −1.6 to −3.9 W m−2. Reducing the uncertainty in the aerosol sizes is important when using AOD to validate models since mass burden errors can then be assumed to be the main AOD error source. This paper explores a procedure that can help achieve this goal.

scholarly journals Analysis of Aerosol Optical Depth and Angstrom Exponents over an AERONET site at Pokhara, Nepal

BIBECHANA ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 118-127
Author(s):  
Jeevan Regmi ◽  
Khem N Poudyal ◽  
Amod Pokhrel ◽  
Madhu Gyawali ◽  
Anthony Barinelli ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Monsoon Season ◽  
Anthropogenic Aerosols ◽  
Annual Average ◽  
Average Value ◽  
Monthly Average ◽  
Aerosol Loading ◽  
Post Monsoon ◽  
Post Monsoon Season

The monthly variability of Aerosol Optical Depth at 0.50 μm (AOD0.50) and Ångström exponents (AE) based on spectral AODs over an Aerosol Robotic Network (AERONET) site Pokhara, are analyzed by using aerosol data of the year 2017. The AOD0.50 are characterized by low average values (0.21± 0.12) in monsoon, and highest values in pre-monsoon (0.67± 0.14) followed by winter (0.46± 0.28) and post-monsoon (0.33±.02) with an overall mean of 0.43 ± 0.02. The average AE obtained by using AODs at 0.44 μm and 0.87 μm is 1.20± 0.04 in pre-monsoon, 1.37± 0.05 in monsoon, 1.41±.01 in post-monsoon, and 1.37± 0.07 in winter with an annual average value of 1.35 ± 0.08. These overall variations of AE indicate that the majority of aerosol loading during the study period was mixture of fine and coarse mode aerosols and the influence of anthropogenic aerosols. The monthly average AOD suggests low aerosol loading in the months of the monsoon season (June to September) than other months of pre-monsoon season (March to May) and post-monsoon season (October and November). BIBECHANA 18 (2021) 118-127

The effect of SARS-CoV-2 on atmospheric particulate matter (AOD) as observed by satellites

2021 ◽  
Author(s):  
Vasilis Margaritis ◽  
Nikolaos Hatzianastassiou ◽  
Marios Bruno Korras Carraca ◽  
Maria Gavrouzou
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Urban Areas ◽  
Human Movement ◽  
Atmospheric Particulate Matter ◽  
Anthropogenic Aerosols ◽  
Industrial Activity ◽  
Aerosol Loading ◽  
Level 3 ◽  
Level 2

<p>After the outbreak of SARS-CoV-2 in December 2019 and its spread worldwide in the following months and seasons, the governments around the world were forced, one by one, to impose lockdown measures in their countries during the ‘Covid Year’ of 2020, trying to slowdown or even stop the spread of the virus. These nationwide lockdowns, included measures that led to the reduction of human movement, such as transportation, in urban areas, while they also diminished the industrial activity. Since transportation and industrial activity are among the major sources of emission of anthropogenic aerosols, it is possible that a change, namely a decrease, of the atmospheric aerosol loading is observed during the year 2020. </p><p>In this study, we examine and quantify the possible effect of worldwide Covid19-related lockdowns on air quality, and more specifically on the aerosol optical depth, which is a good measure of aerosol loading. The analysis is done at global scale using Collection 6.1 Level-3 daily 1°x1° latitude-longitude gridded spectral Aerosol Optical Depth (AOD) data from Moderate Resolution Imaging Spectroradiometer (MODIS) on AQUA satellite during the period 2003-2020. We assess the possible anomaly in AOD values during 2020 by comparing their annual, seasonal and monthly mean values with the corresponding climatological ones for the period 2003-2019. A trend analysis is also performed using time series of deseasonalized AOD anomalies during the period 2003-2020. Special emphasis is given to specific great urban areas, as well as to areas where stricter measures were taken for limiting the virus’ spread. For these areas of interest, a further analysis using higher resolution (10km x 10km) MODIS Level-2  AOD data was made in order to capture local changes in AOD that could be hindered by the coarser resolution Level-3 data. Finally, for these regions, the AOD changes estimated using MODIS Level-2 data are intercompared with the corresponding ones using data from local AERONET (AErosol RObotic NETwork) stations. Preliminary results show a clear reduction in AOD values, mainly starting from April 2020 and becoming more clear in late spring and early summer (May and June) of 2020.</p>

Sensitive Research of Scattering and Absorbing Aerosols on Sky Polarization Pattern

2020 ◽  
Vol 86 (12) ◽  
pp. 767-774
Author(s):  
Wei Chen ◽  
Ge Song ◽  
Haozhong Wang ◽  
Haimeng Zhao ◽  
Jianfang Zhu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Linear Polarization ◽  
Rayleigh Scattering ◽  
Microphysical Properties ◽  
Fine Mode ◽  
Absorbing Aerosols ◽  
Absorbing Property ◽  
Fine Mode Aerosol

Sky polarization patterns are a relatively new and interesting field of polarized remote sensing. However, most current research mainly focuses on Rayleigh scattering or different conditions of aerosol optical depth. In this study, the sky downward polarization patterns are calculated for both degree of linear polarization and angle of polarization with scattering and absorbing aerosol situations. When coarse-mode aerosol changes from scattering to absorbing, the decreasing trend in the sky downward degree-of-linear-polarization largely slows down when aerosol optical depth increases. For fine-mode aerosol, on the other hand, the change of pattern is not sensitive to the absorbing property of aerosol. Sky downward angle-of-polarization patterns for different levels of aerosol optical depth and aerosol modes are similar, with little change. The results suggest that in order to accurately use sky polarization for remote sensing or bionic navigation, it is necessary to characterize aerosol microphysical properties first, especially when coarse absorbing aerosol exists.

scholarly journals Spatiotemporal variability and contribution of different aerosol types to the aerosol optical depth over the Eastern Mediterranean

2016 ◽  
Vol 16 (21) ◽  
pp. 13853-13884 ◽  
Author(s):  
Aristeidis K. Georgoulias ◽  
Georgia Alexandri ◽  
Konstantinos A. Kourtidis ◽  
Jos Lelieveld ◽  
Prodromos Zanis ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Eastern Mediterranean ◽  
Spatiotemporal Variability ◽  
Marine Aerosols ◽  
Anthropogenic Aerosols ◽  
Relative Contribution ◽  
Fine Mode ◽  
Natural Aerosols ◽  
Aerosol Types

Abstract. This study characterizes the spatiotemporal variability and relative contribution of different types of aerosols to the aerosol optical depth (AOD) over the Eastern Mediterranean as derived from MODIS (Moderate Resolution Imaging Spectroradiometer) Terra (March 2000–December 2012) and Aqua (July 2002–December 2012) satellite instruments. For this purpose, a 0.1° × 0.1° gridded MODIS dataset was compiled and validated against sun photometric observations from the AErosol RObotic NETwork (AERONET). The high spatial resolution and long temporal coverage of the dataset allows for the determination of local hot spots like megacities, medium-sized cities, industrial zones and power plant complexes, seasonal variabilities and decadal averages. The average AOD at 550 nm (AOD550) for the entire region is ∼ 0.22 ± 0.19, with maximum values in summer and seasonal variabilities that can be attributed to precipitation, photochemical production of secondary organic aerosols, transport of pollution and smoke from biomass burning in central and eastern Europe and transport of dust from the Sahara and the Middle East. The MODIS data were analyzed together with data from other satellite sensors, reanalysis projects and a chemistry–aerosol-transport model using an optimized algorithm tailored for the region and capable of estimating the contribution of different aerosol types to the total AOD550. The spatial and temporal variability of anthropogenic, dust and fine-mode natural aerosols over land and anthropogenic, dust and marine aerosols over the sea is examined. The relative contribution of the different aerosol types to the total AOD550 exhibits a low/high seasonal variability over land/sea areas, respectively. Overall, anthropogenic aerosols, dust and fine-mode natural aerosols account for ∼ 51, ∼ 34 and ∼ 15 % of the total AOD550 over land, while, anthropogenic aerosols, dust and marine aerosols account ∼ 40, ∼ 34 and ∼ 26 % of the total AOD550 over the sea, based on MODIS Terra and Aqua observations.

scholarly journals Spatio-Temporal Variability of Aerosol Components, Their Optical and Microphysical Properties over North China during Winter Haze in 2012, as Derived from POLDER/PARASOL Satellite Observations

2021 ◽  
Vol 13 (14) ◽  
pp. 2682
Author(s):  
Yang Ou ◽  
Lei Li ◽  
Zhengqiang Li ◽  
Ying Zhang ◽  
Oleg Dubovik ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Air Quality ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Mass Concentration ◽  
North China ◽  
Satellite Observations ◽  
Fine Mode ◽  
The Mean ◽  
Fine Mode Aerosol

Pollution haze is a frequent phenomenon in the North China Plain (NCP) appearing during winter when the aerosol is affected by various pollutant sources and has complex distribution of the aerosol properties, while different aerosol components may have various critical effects on air quality, human health and radiative balance. Therefore, large-scale and accurate aerosol components characterization is urgently and highly desirable but hardly achievable at the regional scale. In this respect, directional and polarimetric remote sensing observations have great potential for providing information about the aerosol components. In this study, a state-of-the-art GRASP/Component approach was employed for attempting to characterize aerosol components in the NCP using POLDER/PARASOL satellite observations. The analysis was done for January 2012 in Beijing (BJ) and Shanxi (SX). The results indicate a peak of the BC mass concentration in an atmospheric column of 82.8 mg/m2 in the SX region, with a mean of 29.2 mg/m2 that is about four times higher than one in BJ (8.9 mg/m2). The mean BrC mass concentrations are, however, higher in BJ (up to ca. 271 mg/m2) than that in SX, which can be attributed to a higher anthropogenic emission. The mean amount of fine ammonium sulfate-like particles observed in the BJ region was three times lower than in SX (131 mg/m2). The study also analyzes meteorological and air quality data for characterizing the pollution event in BJ. During the haze episode, the results suggest a rapid increase in the fine mode aerosol volume concentration associated with a decrease of a scale height of aerosol down to 1500 m. As expected, the values of aerosol optical depth (AOD), absorbing aerosol optical depth (AAOD) and fine mode aerosol optical depth (AODf) are much higher on hazy days. The mass fraction of ammonium sulfate-like aerosol increases from about 13% to 29% and mass concentration increases from 300 mg/m2 to 500 mg/m2. The daily mean PM2.5 concentration and RH independently measured during these reported pollution episodes reach up to 425 g/m3 and 80% correspondingly. The monthly mean mass concentrations of other aerosol components in the BJ are found to be in agreement with the results of previous research works. Finally, a preliminary comparison of these remote sensing derived results with literature and in situ PM2.5 measurements is also presented.

Sign in / Sign up

Export Citation Format

Share Document