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

2020 ◽  
Vol 13 (10) ◽  
pp. 5303-5317
Author(s):  
Dmitry M. Kabanov ◽  
Christoph Ritter ◽  
Sergey M. Sakerin
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
The Arctic ◽  
Data Set ◽  
Arctic Haze ◽  
Fine Mode ◽  
European Arctic ◽  
Sun Photometer ◽  
Highly Correlated ◽  
Fine Mode Aerosol

Abstract. In this work, hourly averaged sun photometer data from Barentsburg and Ny-Ålesund, both located on Spitsbergen in the European Arctic, are compared. Our data set comprises the years from 2002 to 2018 with overlapping measurements from both sites during the period from 2011 to 2018. For more turbid periods (aerosol optical depth, AOD, τ0.5>0.1), we found that Barentsburg is typically more polluted than Ny-Ålesund, especially in the shortwave spectrum. However, the diurnal variation in the AOD is highly correlated. Next, τ was divided into a fine and coarse mode. It was found that the fine-mode aerosol optical depth generally dominates and also shows a larger interannual than seasonal variation. The fine-mode optical depth is in fact largest in spring during the Arctic haze period. Overall the aerosol optical depth seems to decrease (at 500 nm the fine-mode optical depth decreased by 0.016 over 10 years), although this is hardly statistically significant.

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.

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.

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 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 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.

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 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.

scholarly journals Aerosol optical depth and fine-mode fraction retrieval over East Asia using multi-angular total and polarized remote sensing

2012 ◽  
Vol 5 (3) ◽  
pp. 501-516 ◽  
Author(s):  
T. Cheng ◽  
X. Gu ◽  
D. Xie ◽  
Z. Li ◽  
T. Yu ◽  
...  
Keyword(s):  
East Asia ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Lookup Table ◽  
Retrieval Algorithm ◽  
Spatial And Temporal Variability ◽  
Aerosol Retrieval ◽  
Fine Mode ◽  
Sun Photometer ◽  
The Impact

Abstract. A new aerosol retrieval algorithm using multi-angular total and polarized measurements is presented. The algorithm retrieves aerosol optical depth (AOD), fine-mode fraction (FMF) for studying the impact of aerosol on climate change. The retrieval algorithm is based on a lookup table (LUT) method, which assumes that one fine and one coarse lognormal aerosol modes can be combined with proper weightings to represent the ambient aerosol properties. To reduce the ambiguity in retrieval algorithm, the key characteristics of aerosol model over East Asia are constrained using the cluster analysis technique based on the AERONET sun-photometer observation over East Asia, and the fine and coarse modes are not fixed but can vary. A mixing model of bare soil and green vegetation spectra and the Nadal and Breon model for the bidirectional polarized reflectance factor (BPDF) were used to simulate total and polarized surface reflectance of East Asia. By applying the present algorithm to POLDER measurements, three different aerosol cases of clear, polluted and dust are analyzed to test the algorithm. The comparison of retrieved aerosol optical depth (AOD) and fine-mode fraction (FMF) with those of AERONET sun-photometer observations show reliable results. Preliminary validation is encouraging. Using the new aerosol retrieval algorithm for multi-angular total and polarized measurements, the spatial and temporal variability of anthropogenic aerosol optical properties over East Asia, which were observed during a heavy polluted event, were analyzed. Exceptionally high values of aerosol optical depth contributed by fine mode of up to 0.5 (at 0.865 μm), and high values of fine-mode fraction of up to 0.9, were observed in this case study.

scholarly journals VALIDATION AND COMPARISON OF FINE-MODE AEROSOL OPTICAL DEPTH PRODUCTS BETWEEN MODIS AND POLDER

2019 ◽  
Vol XLII-3/W9 ◽  
pp. 51-56
Author(s):  
B. Y. Ge ◽  
Z. Q. Li ◽  
W. Z. Hou ◽  
Y. Zhang ◽  
K. T. Li
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spatial Resolution ◽  
Large Population ◽  
Scale Up ◽  
Global Scale ◽  
Small Population ◽  
Spatial Coverage ◽  
Fine Mode ◽  
Fine Mode Aerosol

Abstract. Fine-mode aerosol usually comes from anthropogenic emissions. The fine-mode aerosol optical depth (AODf) is an important parameter for estimating the particulate matter with an aerodynamic diameter little than 2.5 μm (PM2.5). Compared to the ground-based observations, AODf products from satellite remote sensing have an advantage of high spatial coverage, which is suitable for monitoring the air quality at a regional or global scale. Up to now, AODf products have been released by several sensors, such as the single-angle multi-spectral intensity sensor MODIS and multi-angle multi-spectral polarization sensor POLDER, then what’re the different performances of AODf products from them? In this study, the different spatial resolution AODf products respectively from MODIS latest Collection 6.1 (C6.1, 3 and 10 km) and POLDER latest level 2 version 1.01 (L2, 18 km) were firstly compared with each other in Beijing-Tianjin-Hebei (BTH) domains. Then those products were validated against the ground-based AERosol RObotic NETwork (AERONET) measurements, where has been suffering the severe air pollution since decades ago. The comparison of yearly averaged AODf products between MODIS and POLDER shows a good consistency on the spatial distribution, the higher spatial resolution products of MODIS show more details, both low values of AODf appeared in the northwest area with small population and industry, high values appeared in the southeast area with lots of cities, industries, and large population. However, the whole yearly AODf average values of MODIS are higher than that of POLDER. The results of validation against AERONET show that the accuracy of AODf products at 865 nm from POLDER (R = 0.94, RMSE = 0.05) is high than that at 550 nm of MODIS (3 km: R = 0.69, RMSE = 0.32; 10 km: R = 0.76, RMSE = 0.3). In this study, the performance of different spatial resolutions AODf products retrieved from the intensity (MODIS 3 and 10 km) and polarized sensors (POLDER 18 km) were evaluated. Those results not only have a great significance to provide users amore appropriate choice of the AODf products in the BTH region but also display that the accuracy and spatial resolution of MODIS and POLDER AODf products need to be improved.

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