Characterization of aerosol optical properties and model computed radiative forcing over a semi-arid region, Kadapa in India

Vachaspati, C. Viswanatha; Begam, G. Reshma; Ahammed, Y. Nazeer; Kumar, K. Raghavendra; Reddy, R.R.

doi:10.1016/j.atmosres.2018.03.013

Cited by 19 publications

(3 citation statements)

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“…A preliminary investigation of main aerosol types over the three sites was conducted using the AOD 440 versus AE 440-870 and the FMF 500 versus SSA 440 clustering techniques. The former method (AOD vs AE) has extensively been used by a number of authors (e.g., Bibi et al, 2016;Boiyo et al, 2018a;Kaskaoutis et al, 2007;Kumar et al, 2014Kumar et al, , 2017Patel et al, 2017;Vachaspati et al, 2018, and references therein) over different environments, and the same method is utilized due to plenty of AOD 440 and AE 440-870 data pairs. Using this technique, different types of aerosols were discriminated through determination of physically interpretable cluster regions separated by solid lines that act as threshold values for AOD 440 and AE .…”

Section: Methodology 321 Aerosol-type Discriminationmentioning

confidence: 99%

A 10‐Year Record of Aerosol Optical Properties and Radiative Forcing Over Three Environmentally Distinct AERONET Sites in Kenya, East Africa

et al. 2019

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In the framework of Aerosol Robotic Network (AERONET), the aerosol optical, microphysical, and radiative properties were investigated over three sites (CRPSM_Malindi, Nairobi, and ICIPE_Mbita) in Kenya, East Africa, during 2006–2015. The annual mean (±σ) aerosol optical depth at 440 nm (AOD440) was found high at Mbita (0.27 ± 0.09) followed by Malindi (0.26 ± 0.07), and low at Nairobi (0.19 ± 0.04). Whereas the seasonal mean AOD440 noticed high (low) values during the local dry (wet) seasons. The aerosol optical properties: AOD, single scattering albedo, asymmetry parameter, and complex aerosol refractive index exhibited significant temporal and spectral heterogeneities illustrating the complexity of aerosol types with an abundance of fine‐mode aerosols during the local dry (June–July–August) season. Characterization of major aerosol types revealed the dominance of mixed‐type followed by biomass burning aerosols. The aerosol volume size distribution revealed that the coarse‐ over fine‐mode aerosols showed a significant contribution to the total volume particle concentration, especially at high (>0.3) AOD440. Further, the aerosol columnar number size distribution retrieved from the King's inversion of spectral AOD exhibited a power law distribution affirming multiplicity of aerosol sources. The direct aerosol radiative forcing values simulated in the shortwave region using the Santa Barbara DISORT Atmospheric Radiative Transfer model showed good correlation (r = >0.85) with the AERONET‐derived ones at the top‐of‐atmosphere, bottom‐of‐atmosphere, and within the atmosphere. The annual mean (±σ) top‐of‐atmosphere, bottom‐of‐atmosphere, and within the atmosphere forcing values were found in the range from −8.10 ± 3.75 to −13.23 ± 4.87, −34.54 ± 4.86 to −46.11 ± 10.27, and 26.63 ± 6.43 to 36.24 ± 7.26 W/m2, respectively, with an atmospheric heating rate of 0.74 ± 0.12–1.02 ± 0.20 K/day. The Santa Barbara DISORT Atmospheric Radiative Transfer‐derived direct aerosol radiative forcing exhibited significant temporal heterogeneity with high (low) during the local dry (wet) seasons. Results derived from the present study forms a basis for regional climate change studies and could increase the accuracy of climate models over this unexplored region of Africa.

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Section: Methodology 321 Aerosol-type Discriminationmentioning

confidence: 99%

A 10‐Year Record of Aerosol Optical Properties and Radiative Forcing Over Three Environmentally Distinct AERONET Sites in Kenya, East Africa

et al. 2019

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“…At the same time, more remote sensing products applicable to atmospheric research are constantly appearing, and there are deeper explorations into aerosol characteristics, aerosol types, the validation of the universality of satellite data, etc. Scholars at home and abroad discussed the aerosol optical characteristics and spatial and temporal distribution patterns in different regions through different aerosol optical parameters, such as the AOD, wavelength index, turbidity coefficient, and single-scattered albedo, to reveal the characteristics of the changes in long time series [6][7][8][9][10]. Niu et al explored the spatial and temporal distribution characteristics of the AOD's long time series in five countries of Central Asia by analyzing the base station observation data [11]; Zhang et al analyzed that the changes in the AOD were affected by a combination of meteorological factors (wind speed, air temperature, relative humidity, etc.)…”

Section: Introductionmentioning

confidence: 99%

Study on Accuracy Evaluation of MCD19A2 and Spatiotemporal Distribution of AOD in Arid Zones of Central Asia

Zhu,

Zhang,

Liu

et al. 2023

Sustainability

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The Central Asian arid zone is the largest non-territorial arid zone in the world, so it is particularly important to understand the optical properties of aerosols in this region. In this paper, we validate the MCD19A2 atmospheric aerosol optical depth (AOD) remote sensing data by using ground-based data and measured data. To explore the spatial and temporal changes in aerosols in the Central Asian arid zone as well as the interannual variations and seasonal variations, we characterize the spatial and temporal distributions of the AOD over 20 years. Finally, we analyze the spatial and temporal variations of the AOD in the Central Asian arid zone by using three methods, namely, the Theil–Sen median trend analysis combined with the Mann–Kendall test, coefficient of variation, and Hurst index; analyze the characteristics of the spatial and temporal variations of the AOD in the Central Asian arid zone; and explore the relationships among the AOD, wind speed, and NDVI. This study reveals the characteristics of the long-term changes in the aerosol optical properties in the Central Asian arid zone and provides a scientific basis for estimating the factors affecting climate change.

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“…Moreover, field experiments using a multi-instrument measurement approach showed significant differences between the measured aerosol physical, chemical, and optical characteristics, depending on their natural and anthropogenic sources as well as on local and long-range transport phenomena [14][15][16]. The Mediterranean Basin, for its peculiar geographical location, is characterized by a large diversity of aerosol that coexists in the atmosphere (e.g., mainly marine aerosol, anthropogenic aerosol, local and long-range transported biomass burning aerosol, and mineral dust transported from the Southern Sahara desert region); for this reason, this geographical area is frequently subject to investigations exploiting different methodologies [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Aerosol Characterization with Long-Term AERONET Sun-Photometer Measurements in the Naples Mediterranean Area

et al. 2022

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We report on the characterization of columnar aerosol optical and microphysical properties in the Naples Mediterranean area over a period of five years by the ground-based sun–sky–lunar photometer operating at our observational station in the frame of the AERONET network. Statistical and climatological analyses of daily mean values of aerosol optical depth at 440 nm (AOD440) and Ångström exponent at 440/870 nm (α440/870) allowed for highlighting their typical seasonal behavior. In particular, we observe higher mean values of the AOD440 during summer or spring, which are consistent with an increased frequency of both Saharan dust transport events and biomass burning episodes affecting the measurement area in these periods of the year. Conversely, α440/870 does not show any typical seasonal trend. In order to gain information on the different aerosol contributions along the atmospheric column, the frequency distributions of AOD440 and α440/870 were analyzed and fitted by a superposition of Gaussian functions. The most populated modes are centered at α440/870 = 1.26 ± 0.07 and AOD440 = 0.16 ± 0.01. These values are associated with continental polluted aerosol mixed with sea salt aerosol and correspond to the background conditions typically observed in clear atmospheric conditions. Daily size distributions averaged over each month highlight that the fine aerosol component always prevails over the coarse fraction, except for the few months in which Saharan dust events are particularly frequent. Finally, the mean value of the SSA at 440 nm resulted as 0.94 ± 0.05, while the refractive index real and imaginary part were 1.47 ± 0.07 and (6.5 ± 0.2) × 10−3, respectively. These values are in agreement with those observed in other Mediterranean sites located in Southern Italy, evidencing a rather characteristic feature of the geographical region.

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Characterization of aerosol optical properties and model computed radiative forcing over a semi-arid region, Kadapa in India

Cited by 19 publications

References 64 publications

A 10‐Year Record of Aerosol Optical Properties and Radiative Forcing Over Three Environmentally Distinct AERONET Sites in Kenya, East Africa

A 10‐Year Record of Aerosol Optical Properties and Radiative Forcing Over Three Environmentally Distinct AERONET Sites in Kenya, East Africa

Study on Accuracy Evaluation of MCD19A2 and Spatiotemporal Distribution of AOD in Arid Zones of Central Asia

Aerosol Characterization with Long-Term AERONET Sun-Photometer Measurements in the Naples Mediterranean Area

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