scholarly journals Aerosol radiative forcing and the accuracy of satellite aerosol optical depth retrieval

2003 ◽  
Vol 108 (D24) ◽  
pp. n/a-n/a ◽  
Author(s):  
Petr Chylek ◽  
Brad Henderson ◽  
Michael Mishchenko
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Aerosol Radiative Forcing ◽  
Aerosol Radiative

Aerosol Radiative Forcing and Forcing Efficiency in the UVB for Regions Affected by Saharan and Asian Mineral Dust

2009 ◽  
Vol 66 (4) ◽  
pp. 1033-1040 ◽  
Author(s):  
O. E. García ◽  
A. M. Díaz ◽  
F. J. Expósito ◽  
J. P. Díaz ◽  
A. Redondas ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Climate Model ◽  
Mineral Dust ◽  
Global Climate ◽  
Global Climate Model ◽  
Aerosol Radiative Forcing ◽  
Benchmark Database ◽  
Aerosol Radiative

Abstract The influence of mineral dust on ultraviolet energy transfer is studied for two different mineralogical origins. The aerosol radiative forcing ΔF and the forcing efficiency at the surface ΔFeff in the range 290–325 nm were estimated in ground-based stations affected by the Saharan and Asian deserts during the dusty seasons. UVB solar measurements were taken from the World Ozone and Ultraviolet Data Center (WOUDC) for four Asian stations (2000–04) and from the Santa Cruz Observatory, Canary Islands (2002–03), under Gobi and Sahara Desert influences, respectively. The Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth at 550 nm was used to characterize the aerosol load τ, whereas the aerosol index provided by the Total Ozone Mapping Spectrometer (TOMS) sensor was employed to identify the mineral dust events. The ΔF is strongly affected by the aerosol load, the values found being comparable in both regions during the dusty seasons. Under those conditions, ΔF values as large as −1.29 ± 0.53 W m−2 (τ550 = 0.48 ± 0.24) and −1.43 ± 0.38 W m−2 (τ550 = 0.54 ± 0.26) were reached under Saharan and Asian dust conditions, respectively. Nevertheless, significant differences have been observed in the aerosol radiative forcing per unit of aerosol optical depth in the slant path, τS. The maximum ΔFeff values associated with dust influences were −1.55 ± 0.20 W m−2 τS550−1 for the Saharan region and −0.95 ± 0.11 W m−2 τS550−1 in the Asian area. These results may be used as a benchmark database for establishing aerosol corrections in UV satellite products or in global climate model estimations.

scholarly journals The importance of comprehensive parameter sampling and multiple observations for robust constraint of aerosol radiative forcing

2018 ◽  
Author(s):  
Jill S. Johnson ◽  
Leighton A. Regayre ◽  
Masaru Yoshioka ◽  
Kirsty J. Pringle ◽  
Lindsay A. Lee ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Model Uncertainty ◽  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Observational Constraint ◽  
Aerosol Radiative Forcing ◽  
Multiple Observations ◽  
Aerosol Radiative

Abstract. Observational constraint of simulated aerosol and cloud properties is an essential part of building trustworthy climate models for calculating aerosol radiative forcing. Models are usually tuned to achieve good agreement with observations, but tuning produces just one of many potential variants of a model, so the model uncertainty cannot be determined. Here we estimate the uncertainty in aerosol effective radiative forcing (ERF) in a tuned climate model by constraining 4 million variants of the HadGEM3-UKCA aerosol-climate model to match nine common observations (top-of-atmosphere shortwave flux, aerosol optical depth, PM2.5, cloud condensation nuclei, concentrations of sulphate, black carbon and organic carbon, as well as decadal trends in aerosol optical depth and surface shortwave radiation.) The model uncertainty is calculated by using a perturbed parameter ensemble that samples twenty-seven uncertainties in both the aerosol model and the physical climate model. Focusing over Europe, we show that the aerosol ERF uncertainty can be reduced by about 30 % by constraining it to the nine observations, demonstrating that producing climate models with an observationally plausible base state can contribute to narrowing the uncertainty in aerosol ERF. However, the uncertainty in the aerosol ERF after observational constraint is large compared to the typical spread of a multi-model ensemble. Our results therefore raise questions about whether the underlying multi-model uncertainty would be larger if similar approaches as adopted here were applied more widely. It is hoped that aerosol ERF uncertainty can be further reduced by introducing process-related constraints, however, any such results will be robust only if the enormous number of potential model variants is explored.

Can satellite-derived aerosol optical depth quantify the surface aerosol radiative forcing?

2014 ◽  
Vol 150 ◽  
pp. 151-167 ◽  
Author(s):  
Hui Xu ◽  
Xavier Ceamanos ◽  
Jean-Louis Roujean ◽  
Dominique Carrer ◽  
Yong Xue
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Aerosol Radiative Forcing ◽  
Aerosol Radiative

scholarly journals Fog-induced variations in aerosol optical and physical properties over the Indo-Gangetic Basin and impact to aerosol radiative forcing

2008 ◽  
Vol 26 (6) ◽  
pp. 1345-1354 ◽  
Author(s):  
S. K. Das ◽  
A. Jayaraman ◽  
A. Misra
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Early Morning ◽  
Aerosol Size Distribution ◽  
Aerosol Radiative Forcing ◽  
Solar Elevation ◽  
Relative Humidity Condition ◽  
Aerosol Radiative ◽  
Made In

Abstract. A detailed study on the changes in aerosol physical and optical properties during fog events were made in December 2004 at Hissar (29.13° N, 75.70° E), a city located in the Indo-Gangetic basin. The visible aerosol optical depth was relatively low (0.3) during the initial days, which, however, increased (0.86) as the month progressed. The increasing aerosol amount, the decreasing surface temperature and a higher relative humidity condition were found favoring the formation of fog. The fog event is also found to alter the aerosol size distribution. An increase in the number concentration of the nucleation mode (radius<0.1 μm) particles, along with a decrease in the mode radius showed the formation of freshly nucleated aerosols. In the case of accumulation mode (0.1 μm<radius<1.0 μm) an increase in the mode radius was observed showing the hygroscopic and coagulation growth of particles. The observed aerosol optical depth spectra are model fitted to infer the aerosol components which are further used to compute the aerosol radiative forcing. The top of the atmosphere forcing is found to increase during foggy days due to large backscattering of radiation back to space. It is also shown that during foggy days, as the day progresses the RH value decreases, which reduces the forcing value while the increasing solar elevation increases the forcing value. Thus the fog event which prolongs longer into the daytime has a stronger effect on the diurnally averaged aerosol radiative forcing than those events which are confined only to the early morning hours.

scholarly journals The importance of comprehensive parameter sampling and multiple observations for robust constraint of aerosol radiative forcing

2018 ◽  
Vol 18 (17) ◽  
pp. 13031-13053 ◽  
Author(s):  
Jill S. Johnson ◽  
Leighton A. Regayre ◽  
Masaru Yoshioka ◽  
Kirsty J. Pringle ◽  
Lindsay A. Lee ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Model Uncertainty ◽  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Observational Constraint ◽  
Aerosol Radiative Forcing ◽  
Multiple Observations ◽  
Aerosol Radiative

Abstract. Observational constraint of simulated aerosol and cloud properties is an essential part of building trustworthy climate models for calculating aerosol radiative forcing. Models are usually tuned to achieve good agreement with observations, but tuning produces just one of many potential variants of a model, so the model uncertainty cannot be determined. Here we estimate the uncertainty in aerosol effective radiative forcing (ERF) in a tuned climate model by constraining 4 million variants of the HadGEM3-UKCA aerosol–climate model to match nine common observations (top-of-atmosphere shortwave flux, aerosol optical depth, PM2.5, cloud condensation nuclei at 0.2 % supersaturation (CCN0.2), and concentrations of sulfate, black carbon and organic carbon, as well as decadal trends in aerosol optical depth and surface shortwave radiation.) The model uncertainty is calculated by using a perturbed parameter ensemble that samples 27 uncertainties in both the aerosol model and the physical climate model, and we use synthetic observations generated from the model itself to determine the potential of each observational type to constrain this uncertainty. Focusing over Europe in July, we show that the aerosol ERF uncertainty can be reduced by about 30 % by constraining it to the nine observations, demonstrating that producing climate models with an observationally plausible “base state” can contribute to narrowing the uncertainty in aerosol ERF. However, the uncertainty in the aerosol ERF after observational constraint is large compared to the typical spread of a multi-model ensemble. Our results therefore raise questions about whether the underlying multi-model uncertainty would be larger if similar approaches as adopted here were applied more widely. The approach presented in this study could be used to identify the most effective observations for model constraint. It is hoped that aerosol ERF uncertainty can be further reduced by introducing process-related constraints; however, any such results will be robust only if the enormous number of potential model variants is explored.

scholarly journals Sensitization Towards Aerosol Optical Properties And Radiative Forcing, Real Case In Morocco

2021 ◽  
Vol 319 ◽  
pp. 02027
Author(s):  
Somia Ssouaby ◽  
Hafida Naim ◽  
Abdelouahid Tahiri ◽  
Salmane Bourekkadi
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Regional Warming ◽  
Kuwait University ◽  
Aerosol Radiative Forcing ◽  
Desert Areas ◽  
Aerosol Radiative

Mineral dust is one of the most important aerosol components in the Earth’s atmosphere. Desert aerosol constitute the main types of tropospheric aerosols whose optical property uncertainties are still quite important. In this study, we analyse the variability of aerosol optical depth (AOD), Angstrôm Exponent (α), Single Scattering Albedo (ω0) and aerosol radiative forcing (ARF) of desert aerosol recent measurements, for six AERONET sites covering the belt desert areas: Ouarzazate (Morocco), Tamanrasset (Algeria), El Farafra (Egypt), Mezaira (Unites Arab Emirates), Kuwait University (Kuwait), Dalanzadgad (Mongolia). The annual cycle of the aerosol optical depth dialy averages shows variable values due to the changeable weather and the Sahara source. The highests were recorded at the Sahara site (2.2 at Tamanrasset) and (2.9 at Kuwait-University). The spectral single scattering albedo SSA annual averages varies in the interval (0,8-0.95) indicating dominant scattering. Desert aerosol radiative forcing shows always a negative ARF with a maximums registred in July, -90 W/m2 at surface (Mezaira) and -26 W/m2 at the top of the atmosphere (Kuwait) that imply a general trend towards regional warming of the total column atmosphere with a maximum near +55 W/m2 observed in July at UAE.

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