scholarly journals Modeling Study of the Impact of Heterogeneous Reactions on Dust Surfaces on Aerosol Optical Depth and Direct Radiative Forcing over East Asia in Springtime

2011 ◽  
Vol 4 (6) ◽  
pp. 309-315 ◽  
Author(s):  
Li Jia-Wei ◽  
Han Zhi-Wei
Keyword(s):  
East Asia ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Heterogeneous Reactions ◽  
Direct Radiative Forcing ◽  
The Impact ◽  
Modeling Study

scholarly journals Contribution of ammonium nitrate to aerosol optical depth and direct radiative forcing by aerosols over East Asia

2014 ◽  
Vol 14 (4) ◽  
pp. 2185-2201 ◽  
Author(s):  
R. S. Park ◽  
S. Lee ◽  
S.-K. Shin ◽  
C. H. Song
Keyword(s):  
East Asia ◽  
Ammonium Nitrate ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
East Asian ◽  
Annual Average ◽  
Clear Sky ◽  
Direct Radiative Forcing ◽  
Sky Conditions

Abstract. This study focused on the contribution of ammonium nitrate (NH4NO3) to aerosol optical depth (AOD) and direct radiative forcing (DRF) by aerosols over an East Asian domain. In order to evaluate the contribution, chemistry-transport model (CTM)-estimated AOD was combined with satellite-retrieved AOD, utilizing a data assimilation technique, over East Asia for the entire year of 2006. Using the assimilated AOD and CTM-estimated aerosol optical properties, the DRF by aerosols was estimated over East Asia via a radiative transfer model (RTM). Both assimilated AOD and estimated DRF values showed relatively good agreements with AOD and DRF by aerosols from AERONET. Based on these results, the contributions of NH4NO3 to AOD and DRF by aerosols (ΦAOD and ΦDRF) were estimated for the four seasons of 2006 over East Asia. Both ΦAOD and ΦDRF showed seasonal variations over East Asia within the ranges between 4.7% (summer) and 31.3% (winter) and between 4.7% (summer) and 30.7% (winter), respectively, under clear-sky conditions, showing annual average contributions of 15.6% and 15.3%. Under all-sky conditions, ΦDRF varied between 3.6% (summer) and 24.5% (winter), showing annual average contribution of 12.1% over East Asia. These annual average contributions of NH4NO3 to AOD and DRF are almost comparable to the annual average mass fractions of NH4NO3 in PM2.5 and PM10 (17.0% and 14.0%, respectively). ΦAOD and ΦDRF were even larger in the locations where NH3 and NOx emission rates are strong, such as the central East China (CEC) region and Sichuan Basin. For example, under clear-sky conditions, both ΦAOD and ΦDRF over the CEC region range between 6.9% (summer) and 47.9% (winter) and between 6.7% (summer) and 47.5% (winter), respectively. Based on this analysis, it was concluded that both ΦAOD and ΦDRF cannot be ignored in East Asian air quality and radiative forcing studies, particularly during winter.

scholarly journals Radiative impact of an extreme Arctic biomass-burning event

2018 ◽  
Vol 18 (12) ◽  
pp. 8829-8848 ◽  
Author(s):  
Justyna Lisok ◽  
Anna Rozwadowska ◽  
Jesper G. Pedersen ◽  
Krzysztof M. Markowicz ◽  
Christoph Ritter ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Biomass Burning ◽  
Radiative Forcing ◽  
Radiation Budget ◽  
Plane Parallel ◽  
Direct Radiative Forcing ◽  
The Mean ◽  
The Impact

Abstract. The aim of the presented study was to investigate the impact on the radiation budget of a biomass-burning plume, transported from Alaska to the High Arctic region of Ny-Ålesund, Svalbard, in early July 2015. Since the mean aerosol optical depth increased by the factor of 10 above the average summer background values, this large aerosol load event is considered particularly exceptional in the last 25 years. In situ data with hygroscopic growth equations, as well as remote sensing measurements as inputs to radiative transfer models, were used, in order to estimate biases associated with (i) hygroscopicity, (ii) variability of single-scattering albedo profiles, and (iii) plane-parallel closure of the modelled atmosphere. A chemical weather model with satellite-derived biomass-burning emissions was applied to interpret the transport and transformation pathways. The provided MODTRAN radiative transfer model (RTM) simulations for the smoke event (14:00 9 July–11:30 11 July) resulted in a mean aerosol direct radiative forcing at the levels of −78.9 and −47.0 W m−2 at the surface and at the top of the atmosphere, respectively, for the mean value of aerosol optical depth equal to 0.64 at 550 nm. This corresponded to the average clear-sky direct radiative forcing of −43.3 W m−2, estimated by radiometer and model simulations at the surface. Ultimately, uncertainty associated with the plane-parallel atmosphere approximation altered results by about 2 W m−2. Furthermore, model-derived aerosol direct radiative forcing efficiency reached on average −126 W m-2/τ550 and −71 W m-2/τ550 at the surface and at the top of the atmosphere, respectively. The heating rate, estimated at up to 1.8 K day−1 inside the biomass-burning plume, implied vertical mixing with turbulent kinetic energy of 0.3 m2 s−2.

scholarly journals Contribution of ammonium nitrate to aerosol optical depth and direct radiative forcing by aerosols over East Asia

2013 ◽  
Vol 13 (7) ◽  
pp. 19193-19235
Author(s):  
R. S. Park ◽  
S. J. Lee ◽  
S.-K. Shin ◽  
C. H. Song
Keyword(s):  
East Asia ◽  
Ammonium Nitrate ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
East Asian ◽  
Annual Average ◽  
Clear Sky ◽  
Direct Radiative Forcing ◽  
Sky Conditions

Abstract. This study focused on the contribution of ammonium nitrate (NH4NO3) to aerosol optical depth (AOD) and direct radiative forcing (DRF) by aerosols over an East Asian domain. In order to evaluate the contribution, CTM-estimated AOD was combined with satellite-retrieved AOD, utilizing a data assimilation technique, over East Asia for the entire year of 2006. Using the assimilated AOD and CTM-estimated aerosol optical properties, the DRF by aerosols was estimated over East Asia via a radiative transfer model (RTM). Both assimilated AOD and estimated DRF values showed relatively good agreements with AOD and DRF by aerosols from AERONET. Based on these results, the contributions of NH4NO3 to AOD and DRF by aerosols (ΦAOD and ΦDRF) were estimated for four seasons of 2006 over East Asia. Both ΦAOD and ΦDRF showed seasonal variations over East Asia within the ranges between 4.7% (summer) and 31.3% (winter) and between 4.7% (summer) and 30.7% (winter), respectively, under clear-sky conditions, showing annual average contributions of 15.6% and 15.3%. Under all-sky conditions, ΦDRF varied between 3.6% (summer) and 24.5% (winter), showing annual average contribution of 12.1% over East Asia. These annual average contributions of NH4NO3 to AOD and DRF are almost comparable to the annual average mass fractions of NH4NO3 to PM2.5 and PM10 (17.0% and 14.0%, respectively). ΦAOD and ΦDRF were even larger in the locations where NH3 and NOx emission rates are strong like the Central East China (CEC) region and Sichuan basin. For example, under clear-sky conditions, both ΦAOD and ΦDRF over the CEC region range between 6.9% (summer) and 47.9% (winter) and between 6.7% (summer) and 47.5% (winter), respectively. Based on this analysis, it was concluded that both ΦDRF and ΦDRF cannot be ignored in East Asian air quality and radiative forcing studies, particularly during winter.

scholarly journals Impact of a Strong Biomass Burning Event on the Radiative Forcing in the Arctic

2017 ◽  
Author(s):  
Justyna Lisok ◽  
Anna Rozwadowska ◽  
Jesper G. Pedersen ◽  
Krzysztof M. Markowicz ◽  
Christoph Ritter ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Biomass Burning ◽  
Radiative Forcing ◽  
Radiation Budget ◽  
The Arctic ◽  
Plane Parallel ◽  
Direct Radiative Forcing ◽  
The Mean ◽  
The Impact

Abstract. The aim of the presented study was to investigate the impact on the radiation budget of biomass burning smoke plume transported from Alaska to high Arctic region (Ny-Alesund, Svalbard) in early July 2015. This high aerosol load event is considered exceptional in the last 25 years with mean aerosol optical depth increased by the factor of 10 in comparison to the average summer background values. We utilised in-situ data with hygroscopic growth equations as well as remote sensing measurements as inputs to radiative transfer models with an objective to estimate biases associated with (i) hygroscopicity, (ii) variability of ω profiles and (iii) plane-parallel closure of the modelled atmosphere. A chemical weather model with satellite-derived biomass burning emissions was used to interpret the transport and transformations pathways. Provided MODTRAN simulations resulted in the mean aerosol direct radiative forcing on the level of −78.9 W m−2 and −47.0 W m−2 at the surface and the top of the atmosphere respectively for the mean value of aerosol optical depth equal to 0.64 at 550 nm. It corresponded to the average clear-sky direct radiative forcing of −43.3 W m−2 estimated by radiometers and model simulations. Furthermore, model-derived aerosol direct radiative forcing efficiency reached on average −126 W m−2 / τ550 and −71 W m−2 / τ550 at the surface and at the top of the atmosphere. Estimated heating rate up to 1.8 K day−1 inside the BB plume implied vertical mixing with the turbulent kinetic energy of 0.3 m2 s−2. Ultimately, uncertainty connected with the plane-parallel atmosphere approximation altered results by about 2 W m−2.

Development of RAMS-CMAQ to Simulate Aerosol Optical Depth and Aerosol Direct Radiative Forcing and Its Application to East Asia

2009 ◽  
Vol 2 (6) ◽  
pp. 368-375 ◽  
Author(s):  
Han Xiao ◽  
Zhange Mei-Gen ◽  
Liu Xiao-Hong ◽  
Steven Ghan ◽  
Xin Jin-Yuan ◽  
...  
Keyword(s):  
East Asia ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Direct Radiative Forcing

The Impact of Dust Storms on Aerosol Optical Depth and Radiative Forcing

2020 ◽  
Vol 16 (1) ◽  
pp. 1-14
Author(s):  
Monim Jiboori ◽  
Nadia Abed ◽  
Mohamed Abdel Wahab
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Dust Storms ◽  
The Impact

scholarly journals Influence of observed diurnal cycles of aerosol optical depth on aerosol direct radiative effect

2013 ◽  
Vol 13 (15) ◽  
pp. 7895-7901 ◽  
Author(s):  
A. Arola ◽  
T. F. Eck ◽  
J. Huttunen ◽  
K. E. J. Lehtinen ◽  
A. V. Lindfors ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Radiative Effect ◽  
Diurnal Variability ◽  
Diurnal Cycles ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Impact

Abstract. The diurnal variability of aerosol optical depth (AOD) can be significant, depending on location and dominant aerosol type. However, these diurnal cycles have rarely been taken into account in measurement-based estimates of aerosol direct radiative forcing (ADRF) or aerosol direct radiative effect (ADRE). The objective of our study was to estimate the influence of diurnal aerosol variability at the top of the atmosphere ADRE estimates. By including all the possible AERONET sites, we wanted to assess the influence on global ADRE estimates. While focusing also in more detail on some selected sites of strongest impact, our goal was to also see the possible impact regionally. We calculated ADRE with different assumptions about the daily AOD variability: taking the observed daily AOD cycle into account and assuming diurnally constant AOD. Moreover, we estimated the corresponding differences in ADREs, if the single AOD value for the daily mean was taken from the the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra or Aqua overpass times, instead of accounting for the true observed daily variability. The mean impact of diurnal AOD variability on 24 h ADRE estimates, averaged over all AERONET sites, was rather small and it was relatively small even for the cases when AOD was chosen to correspond to the Terra or Aqua overpass time. This was true on average over all AERONET sites, while clearly there can be much stronger impact in individual sites. Examples of some selected sites demonstrated that the strongest observed AOD variability (the strongest morning afternoon contrast) does not typically result in a significant impact on 24 h ADRE. In those cases, the morning and afternoon AOD patterns are opposite and thus the impact on 24 h ADRE, when integrated over all solar zenith angles, is reduced. The most significant effect on daily ADRE was induced by AOD cycles with either maximum or minimum AOD close to local noon. In these cases, the impact on 24 h ADRE was typically around 0.1–0.2 W m−2 (both positive and negative) in absolute values, 5–10% in relative ones.

scholarly journals Estimate of surface direct radiative forcing of desert dust from atmospheric modulation of the aerosol optical depth

2013 ◽  
Vol 13 (11) ◽  
pp. 5647-5654 ◽  
Author(s):  
A. di Sarra ◽  
D. Fuà ◽  
D. Meloni
Keyword(s):  
Water Vapour ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spectral Range ◽  
Radiative Forcing ◽  
Oscillation Amplitude ◽  
Aerosol Layer ◽  
Surface Irradiance ◽  
Perturbation Versus ◽  
Direct Radiative Forcing

Abstract. Measurements carried out on the island of Lampedusa, in the central Mediterranean, on 7 September 2005, show the occurrence of a quasi-periodic oscillation of aerosol optical depth, column water vapour, and surface irradiance in different spectral bands. The oscillation has a period of about 13 min and is attributed to the propagation of a gravity wave able to modify the vertical structure of the planetary boundary layer, as also confirmed by satellite images. The wave occurred during a Saharan dust event. The oscillation amplitude is about 0.1 for the aerosol optical depth, and about 0.4 cm for the column water vapour. The modulation of the downward surface irradiances is in opposition of phase with respect to aerosol optical depth and water vapour column variations. The perturbation of the downward irradiance produced by the aerosols is determined by comparing the measured irradiances with estimated irradiances at a fixed value of the aerosol optical depth, and by correcting for the effect of the water vapour in the shortwave spectral range. The direct radiative forcing efficiency, i.e., the radiative perturbation of the net surface irradiance produced by a unit of optical depth aerosol layer, is determined at different solar zenith angles as the slope of the irradiance perturbation versus the aerosol optical depth. The estimated direct surface forcing efficiency at about 60° solar zenith angle is −(181 ± 17) W m−2 in the shortwave, and −(83 ± 7) W m−2 in the photosynthetic spectral range. The estimated daily average forcing efficiencies are of about −79 and −46 W m−2 for the shortwave and photosynthetic spectral range, respectively.

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