A Method for Predicting Atmospheric Aerosol Scattering Coefficients in the Infrared

1970 ◽  
Vol 9 (6) ◽  
pp. 1337 ◽  
Author(s):  
E. A. Barnhardt ◽  
J. L. Streete
Keyword(s):  
Atmospheric Aerosol ◽  
Scattering Coefficients ◽  
Aerosol Scattering

scholarly journals A study on the aerosol extinction-to-backscatter ratio with combination of micro-pulse LIDAR and MODIS over Hong Kong

2006 ◽  
Vol 6 (11) ◽  
pp. 3243-3256 ◽  
Author(s):  
Q. S. He ◽  
C. C. Li ◽  
J. T. Mao ◽  
A. K. H. Lau ◽  
P. R. Li
Keyword(s):  
Hong Kong ◽  
Aerosol Extinction ◽  
Scattering Coefficients ◽  
Aerosol Scattering ◽  
Microphysical Parameters ◽  
Lidar Measurements ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Lidar Equation ◽  
Micro Pulse Lidar

Abstract. The aerosol extinction-to-backscatter ratio is an important parameter for inverting LIDAR signals in the LIDAR equation. It is a complicated function of the aerosol microphysical characteristics. In this paper, a method to retrieve the column-averaged aerosol extinction-to-backscatter ratio by constraining the aerosol optical depths (AOD) from a Micro-pulse LIDAR (MPL) by the AOD measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. Both measurements were taken on cloud free days between 1 May 2003 and 30 June 2004 over Hong Kong, a coastal city in south China. Simultaneous measurements of aerosol scattering coefficients with a forward scattering visibility sensor are compared with the LIDAR retrieval of aerosol extinction coefficients. The data are then analyzed to determine seasonal trends of the aetrosol extinction-to-backscatter ratio. In addition, the relationships between the extinction-to-backscatter ratio and wind conditions as well as other aerosol microphysical parameters are presented. The mean aerosol extinction-to-backscatter ratio for the whole period was found to be 29.1±5.8 sr, with a minimum of 18 sr in July 2003 and a maximum of 44 sr in March 2004. The ratio is lower in summer because of the dominance of oceanic aerosols in association with the prevailing southwesterly monsoon. In contrast, relatively larger ratios are noted in spring and winter because of the increased impact of local and regional industrial pollutants associated with the northerly monsoon. The extended LIDAR measurements over Hong Kong provide not only a more accurate retrieval of aerosol extinction coefficient profiles, but also significant substantial information for air pollution and climate studies in the region.

scholarly journals Radiative Impact of Fireworks at a Tropical Indian Location: A Case Study

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
B. P. Singh ◽  
A. K. Srivastava ◽  
S. Tiwari ◽  
S. Singh ◽  
R. K. Singh ◽  
...  
Keyword(s):  
Behavioral Change ◽  
Radiative Forcing ◽  
Gangetic Plain ◽  
Scattering Coefficients ◽  
Aerosol Absorption ◽  
Aerosol Scattering ◽  
Radiative Impact ◽  
Diwali Festival ◽  
Indo Gangetic Plain

During Diwali festival, extensive burning of crackers and fireworks is made. Weeklong intensive observational campaign for aerosol study was carried out at a representative urban location in the eastern Indo-Gangetic Plain (IGP), Varanasi (25.3°N, 83.0°E), from October 29 to November 04, 2005 (Diwali on November 01, 2005), to investigate behavioral change of aerosol properties and radiative forcing between firework affected and nonaffected periods. Results show a substantial increase (~27%) in aerosol optical depth, aerosol absorption coefficients, and aerosol scattering coefficients during affected period as compared to non-affected periods. Magnitudes of radiative forcing at top of atmosphere during affected and non-affected periods are found to be +10 ± 1 and +12 ± 1 Wm−2, respectively, which are −31 ± 7 and −17 ± 5 Wm−2, respectively, at surface. It suggests an additional cooling of ~20% at top of atmosphere, ~45% cooling at surface, and additional atmospheric heating of 0.23 Kday−1during fireworks affected period, which is ~30% higher than the non-affected period average.

scholarly journals Seasonal variation of aerosol water uptake and its impact on the direct radiative effect at Ny-Ålesund, Svalbard

2014 ◽  
Vol 14 (14) ◽  
pp. 7445-7460 ◽  
Author(s):  
N. Rastak ◽  
S. Silvergren ◽  
P. Zieger ◽  
U. Wideqvist ◽  
J. Ström ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Water Uptake ◽  
Aerosol Particles ◽  
The Arctic ◽  
Ambient Atmosphere ◽  
Radiative Effect ◽  
Hygroscopic Growth ◽  
Scattering Coefficients ◽  
Aerosol Scattering ◽  
July August September

Abstract. In this study we investigated the impact of water uptake by aerosol particles in ambient atmosphere on their optical properties and their direct radiative effect (ADRE, W m−2) in the Arctic at Ny-Ålesund, Svalbard, during 2008. To achieve this, we combined three models, a hygroscopic growth model, a Mie model and a radiative transfer model, with an extensive set of observational data. We found that the seasonal variation of dry aerosol scattering coefficients showed minimum values during the summer season and the beginning of fall (July-August-September), when small particles (< 100 nm in diameter) dominate the aerosol number size distribution. The maximum scattering by dry particles was observed during the Arctic haze period (March-April-May) when the average size of the particles was larger. Considering the hygroscopic growth of aerosol particles in the ambient atmosphere had a significant impact on the aerosol scattering coefficients: the aerosol scattering coefficients were enhanced by on average a factor of 4.30 ± 2.26 (mean ± standard deviation), with lower values during the haze period (March-April-May) as compared to summer and fall. Hygroscopic growth of aerosol particles was found to cause 1.6 to 3.7 times more negative ADRE at the surface, with the smallest effect during the haze period (March-April-May) and the highest during late summer and beginning of fall (July-August-September).

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