Analysis of the Transport of Aerosols over the North Tropical Atlantic Ocean Using Time Series of POLDER/PARASOL Satellite Data

Fréville, H.; Chami, Malik; Mallet, Marc

doi:10.3390/rs12050757

Cited by 3 publications

(1 citation statement)

References 114 publications

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“…The default spring-summer seasonal dependence of the U.S Standard Atmosphere is chosen for tropospheric aerosols for layers from 2 to 10 km, and the background stratospheric aerosol profile for layers above 10 km. The model gives a total aerosol optical depth of ≈ 0.16 at 550 nm, which is in agreement with previous studies of aerosol profiles over the North Atlantic [39][40][41][42] and a relative difference of only 1.43% compared to the official atmospheric model for CTA-N used in sim_telarray.…”

Section: Atmospheric Modellingsupporting

confidence: 89%

Performance and systematic uncertainties of CTA-North in conditions of reduced atmospheric transmission

Pecimotika¹,

Prester²,

Hrupec³

et al. 2023

J. Cosmol. Astropart. Phys.

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The Cherenkov Telescope Array (CTA) is the next-generation stereoscopic system of Imaging Atmospheric Cherenkov Telescopes (IACTs). In IACTs, the atmosphere is used as a calorimeter to measure the energy of extensive air showers induced by cosmic gamma rays, which brings along a series of constraints on the precision to which energy can be reconstructed. The presence of clouds during observations can severely affect Cherenkov light yield, contributing to the systematic uncertainty in energy scale calibration. To minimize these systematic uncertainties, a calibration of telescopes is of great importance. For this purpose, the influence of cloud transmission and altitude on CTA-N performance degradation was investigated using detailed Monte Carlo simulations for the case where no action is taken to correct for the effects of clouds. Variations of instrument response functions in the presence of clouds are presented. In the presence of clouds with low transmission (≤ 80%) the energy resolution is aggravated by 30% at energies below 1 TeV, and by 10% at higher energies. For higher transmissions, the energy resolution is worse by less than 10% in the whole energy range. The angular resolution varies up to 10% depending both on the transmission and altitude of the cloud. The sensitivity of the array is most severely reduced at lower energies, even by 60% at 40 GeV, depending on the clouds' properties. A simple semi-analytical model of sensitivity degradation has been introduced to summarize the influence of clouds on sensitivity and provide useful scaling relations.

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Section: Atmospheric Modellingsupporting

confidence: 89%

Performance and systematic uncertainties of CTA-North in conditions of reduced atmospheric transmission

Pecimotika¹,

Prester²,

Hrupec³

et al. 2023

J. Cosmol. Astropart. Phys.

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Using satellite multi-angle polarization measurements to characterize atmospheric aerosol above Bohai Bay

Salyuk,

Stepochkin,

Shmirko

et al. 2024

Advances in Space Research

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15-year variability of desert dust optical depth on global and regional scales

et al. 2021

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Abstract. This study aims to investigate global, regional and seasonal temporal dust changes as well as the effect of dust particles on total aerosol loading using the ModIs Dust AeroSol (MIDAS) fine-resolution dataset. MIDAS delivers dust optical depth (DOD) at fine spatial resolution (0.1∘×0.1∘) spanning from 2003 to 2017. Within this study period, the dust burden increased across the central Sahara (up to 0.023 yr−1) and Arabian Peninsula (up to 0.024 yr−1). Both regions observed their highest seasonal trends in summer (up to 0.031 yr−1). On the other hand, declining DOD trends are encountered in the western (down to −0.015 yr−1) and eastern (down to −0.023 yr−1) Sahara, the Bodélé Depression (down to −0.021 yr−1), the Thar (down to −0.017 yr−1) and Gobi (down to −0.011 yr−1) deserts, and the Mediterranean Basin (down to −0.009 yr−1). In spring, the most negative seasonal trends are recorded in the Bodélé Depression (down to −0.038 yr−1) and Gobi Desert (down to −0.023 yr−1), whereas they are in the western (down to −0.028 yr−1) and the eastern Sahara (down to −0.020 yr−1) and the Thar Desert (down to −0.047 yr−1) in summer. Over the western and eastern sector of the Mediterranean Basin, the most negative seasonal trends are computed at summer (down to −0.010 yr−1) and spring (down to −0.006 yr−1), respectively. The effect of DOD on the total aerosol optical depth (AOD) change is determined by calculating the DOD-to-AOD trend ratio. Over the Sahara the median ratio values range from 0.83 to 0.95, whereas in other dust-affected areas (Arabian Peninsula, southern Mediterranean, Thar and Gobi deserts) the ratio value is approximately 0.6. In addition, a comprehensive analysis of the factors affecting the sign, the magnitude and the statistical significance of the calculated trends is conducted. Firstly, the implications of the implementation of the geometric mean instead of the arithmetic mean for trend calculations are discussed, revealing that the arithmetic-based trends tend to overestimate compared to the geometric-based trends over both land and ocean. Secondly, an analysis interpreting the differences in trend calculations under different spatial resolutions (fine and coarse) and time intervals is conducted.

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Analysis of the Transport of Aerosols over the North Tropical Atlantic Ocean Using Time Series of POLDER/PARASOL Satellite Data

Cited by 3 publications

References 114 publications

Performance and systematic uncertainties of CTA-North in conditions of reduced atmospheric transmission

Performance and systematic uncertainties of CTA-North in conditions of reduced atmospheric transmission

Using satellite multi-angle polarization measurements to characterize atmospheric aerosol above Bohai Bay

15-year variability of desert dust optical depth on global and regional scales

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