scholarly journals Effect of Urban Growth on Aerosol Optical Depth—Tucson, Arizona, 35 Years Later

2014 ◽  
Vol 53 (8) ◽  
pp. 1876-1885 ◽  
Author(s):  
Gouri Prabhakar ◽  
Eric A. Betterton ◽  
W. Conant ◽  
Benjamin M. Herman
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Urban Growth ◽  
Solar Irradiance ◽  
Monthly Variation ◽  
The Past ◽  
Ozone Column

AbstractMultiwavelength solar irradiance measurements between 400 and 900 nm were made on cloudless days in Tucson, Arizona, over a 30-month period between March 2010 and August 2012. They were analyzed to simultaneously retrieve aerosol optical depth (AOD) and ozone column abundance and to examine their monthly variation. These retrievals were compared with results from a similar study done at the same location between 1975 and 1977. The near tripling of population in Tucson over the past 35 years may have contributed to a 19% increase in the AOD, and the annual-mean ozone column abundance was found to be 11% lower than that inferred during the mid-1970s.

scholarly journals Measurements of UV Aerosol Optical Depth in the French Southern Alps

2008 ◽  
Vol 8 (1) ◽  
pp. 161-179
Author(s):  
J. Lenoble ◽  
C. Brogniez ◽  
A. de La Casinière ◽  
T. Cabot ◽  
V. Buchard ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Solar Irradiance ◽  
Preliminary Analysis ◽  
Late Summer ◽  
Southern Alps

Abstract. Routine measurements of global and diffuse UV irradiances at Briançon station (1310 m a.s.l.) are used to retrieve the direct solar irradiance and the aerosol optical depth (AOD), for cloudless days. Data of three years (2003, 2004, 2005) are analyzed; the results confirm those of a preliminary analysis for 2001, 2002. The atmosphere is very clear in winter, with AODs between 0.05 and 0.1. The turbidity increases slowly in spring, starting end of February, with AODs around 0.2–0.3 in mid summer, some values reaching 0.4. A similar behaviour is observed for all years, with somewhat higher values in late summer for the year 2003.

scholarly journals Wintertime pollution over the Eastern Indo-Gangetic Plains as observed from MOPITT, CALIPSO and tropospheric ozone residual data

2010 ◽  
Vol 10 (24) ◽  
pp. 12273-12283 ◽  
Author(s):  
J. Kar ◽  
M. N. Deeter ◽  
J. Fishman ◽  
Z. Liu ◽  
A. Omar ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Tropospheric Ozone ◽  
Lower Troposphere ◽  
Satellite Observations ◽  
Gangetic Plains ◽  
Winter Conditions ◽  
Low Altitude ◽  
Ozone Column

Abstract. A large wintertime increase in pollutants has been observed over the eastern parts of the Indo Gangetic Plains. We use improved version 4 carbon monoxide (CO) retrievals from the Measurements of Pollution in the Troposphere (MOPITT) along with latest version 3 aerosol data from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar instrument and the tropospheric ozone residual products to characterize this pollution pool. The feature is seen primarily in the lower troposphere from about November to February with strong concomitant increases in CO and aerosol optical depth (AOD). The signature of the feature is also observed in tropospheric ozone column data. The height resolved aerosol data from CALIPSO confirm the trapping of the pollution pool at the lowest altitudes. The observations indicate that MOPITT can capture this low altitude phenomenon even in winter conditions as indicated by the averaging kernels.

scholarly journals Comparative Study of the Influence of Air Pollution on UVI at Maitri in Antarctica and New Delhi in India

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Nandita D. Ganguly
Keyword(s):  
Air Pollution ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Negative Correlation ◽  
Total Ozone ◽  
Surface Ozone ◽  
New Delhi ◽  
Increasing Trend ◽  
Ultraviolet Irradiance ◽  
Ozone Column

The influence of air pollution on the erythemal ultraviolet irradiance (UVI) reaching the earth's surface has been investigated at the Indian Antarctic station Maitri and compared with that at New Delhi, the capital of India, over a period of three years from 2005 to 2007. Total ozone column (TOC), surface ozone, NO2 column, middle tropospheric SO2 column, and BrO column are observed to exhibit a deceasing trend at Maitri, having a clean and pristine environment, while UVI and aerosol optical depth at 500 nm exhibit an increasing trend. This negative correlation suggests that O3, NO2, SO2, and BrO act as filters against erythemal ultraviolet irradiance reaching the earth's surface, while the aerosols, which are present in the atmosphere of Maitri, may not be either very effective in filtering out the UVI reaching the earth's surface or may not be large enough to produce measurable effects on UVI. TOC and BrO column are observed to exhibit a deceasing trend at New Delhi, having comparatively higher levels of pollution, while UVI, NO2 column, middle tropospheric SO2 column, surface ozone, and aerosol optical depth at 500 nm exhibit an increasing trend. This suggests that TOC and BrO act as filters against UVI, while NO2, surface ozone, SO2, and aerosols in the atmosphere of New Delhi may not be large enough to produce measurable effects on UVI.

scholarly journals Aerosol radiative forcings induced by substantial changes in anthropogenic emissions in China from 2008 to 2016

2021 ◽  
Vol 21 (8) ◽  
pp. 5965-5982
Author(s):  
Mingxu Liu ◽  
Hitoshi Matsui
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Eastern China ◽  
Radiation Budget ◽  
Anthropogenic Emissions ◽  
Radiative Forcings ◽  
The Past ◽  
Positive Direct ◽  
Aerosol Radiative

Abstract. Anthropogenic emissions in China play an important role in altering the global radiation budget. Over the past decade, the strong clean-air policies in China have resulted in substantial reductions of anthropogenic emissions of sulfur dioxide (SO2) and primary particulate matter, and air quality in China has consequently improved. However, the resultant aerosol radiative forcings have been poorly understood. In this study, we used an advanced global climate model integrated with the latest localized emission inventory to quantify the aerosol radiative forcings by the changes of anthropogenic emissions in China between 2008 and 2016. By comparing with multiple observation datasets, our simulations reproduced the considerable reductions of sulfate and black carbon (BC) mass loadings reasonably well over eastern China (the key region subject to stringent emission controls) during the period and accordingly showed a clear decline in both aerosol optical depth and absorption aerosol optical depth. The results revealed a regional annual mean positive direct radiative forcing (DRF) of +0.29 W m−2 at the top of the atmosphere (TOA) due to the reduction of SO2 emissions. This positive aerosol radiative forcing was comprised of diminished sulfate scattering (+0.58 W m−2), enhanced nitrate radiative effects (−0.29 W m−2), and could be completely offset by the concurrent reduction of BC emissions that induced a negative BC DRF of −0.33 W m−2. Despite the small net aerosol DRF (−0.05 W m−2) at the TOA, aerosol–radiation interactions could explain the surface brightening in China over the past decade. The overall reductions in aerosol burdens and associated optical effects mainly from BC and sulfate enhanced the regional annual mean downward solar radiation flux at the surface by +1.0 W m−2 between 2008 and 2016. The enhancement was in general agreement with a long-term observational record of surface energy fluxes in China. We also estimated that aerosol effects on cloud radiative forcings may have played a dominant role in the net aerosol radiative forcings at the TOA in China and over the northern Pacific Ocean during the study period. This study will facilitate more informed assessment of climate responses to projected emissions in the future as well as to sudden changes in human activities (e.g., the COVID-19 lockdown).

scholarly journals Optical properties and effects on direct solar irradiance of aerosols: Asian East case

2021 ◽  
Vol 234 ◽  
pp. 00054
Author(s):  
Abdelmoula Ben-tayeb ◽  
Mohammed Diouri ◽  
Abdelouahid Tahiri ◽  
Rajae Meziane
Keyword(s):  
Particle Size ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Solar Irradiance ◽  
Volume Concentration ◽  
Size Distributions ◽  
Almost Periodic ◽  
Particle Size Distributions ◽  
Chiang Mai ◽  
Aerosol Type

Atmospheric aerosol is an important factor that affects solar irradiance. In this study, we examined the total atmospheric optical depth, aerosol optical depth AOD and the vertical particle size distribution in East Asia in terms of aerosol type during three years. The temporal variation of the aerosol optical depth for each site showed a constant mode renewed each year, the large AOD0,5 are recorded in spring and summer in an almost periodic manner, with maximums around 0.95 in Seoul, 0.08 in Chiang Mai and 1.34 in EPA-NCU. The particle size distributions under a bimodal lognormal form present a remarkable increase in volume concentration of fine and coarse modes during spring. The aerosols reduce solar irradiance by 37.33 ± 0.78% in Chiang Mai, 33.48 ± 6.43% in EPA-NCU and 38.59 ± 3.86% in Seoul.

scholarly journals Trends of Aerosol Optical Properties over the Heavy Industrial Zone of Northeastern Asia in the Past Decade (2004–15)

2018 ◽  
Vol 75 (6) ◽  
pp. 1741-1754 ◽  
Author(s):  
Dandan Zhao ◽  
Jinyuan Xin ◽  
Chongshui Gong ◽  
Xin Wang ◽  
Yongjing Ma ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Source Area ◽  
Industrial Zone ◽  
Anthropogenic Aerosols ◽  
Northeastern Asia ◽  
Air Masses ◽  
The Past ◽  
Aerosol Emission

The heavy industrial zone of northeastern Asia is dominated by year-round industrial scattering aerosols that undergo hygroscopic growth in summer. With the rapid economic development over the past decade, aerosol optical depth (AOD) has increased (6.35% yr−1) with an annual-mean AOD of 0.61 ± 0.13. Simultaneously, the aerosol particle size and aerosol scattering have increased, with an annual-mean scattering aerosol optical depth (SAOD) reaching 0.58 ± 0.15. However, considering that the annual AOD/gross domestic product (GDP) per capita decreased, the environmental degradation caused by aerosol emission is expected to reach a turning point based on the environmental Kuznets curve (EKC) hypothesis. In addition, annual-mean radiative forcing at the top, bottom, and interior of the atmospheric column reached −2.35 ± 2.33, −54.16 ± 7.26, and 51.81 ± 7.93 W m−2, respectively. The increase in unit SAOD contributes to the growth in net negative top-of-atmosphere (TOA) forcing and surface (SFC) forcing, and unit absorption aerosol optical depth (AAOD) increases together with atmosphere (ATM) forcing. Moreover, the cooling effect of aerosols on the Earth–atmosphere system showed an increase over the most recent 10 years related to the increase in scattering aerosol from development in the old industrial base. Except for local sources, under the western air masses, the circum–Bohai Sea economic zone was the potential source area of anthropogenic aerosols throughout the year with annual daily mean AOD, single-scattering albedo (SSA), TOA forcing, and SFC forcing values of 0.88, 0.93, −8.08, and −63.05 W m−2, respectively. The Mongolian Plateau was the potential natural dust source area under the northeastern air masses.

scholarly journals Ultraviolet Radiation modelling using output from the Chemistry Climate Model Initiative

2018 ◽  
Author(s):  
Kévin Lamy ◽  
Thierry Portafaix ◽  
Béatrice Josse ◽  
Colette Brogniez ◽  
Sophie Godin-Beekmann ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Northern Hemisphere ◽  
Total Ozone ◽  
Climate Model ◽  
Sudden Increase ◽  
Total Ozone Column ◽  
Rcp 8.5 ◽  
Ozone Column

Abstract. We have derived values of the Ultraviolet Index (UVI) at solar noon from the Tropospheric Ultraviolet Model (TUV) driven by ozone, temperature and aerosol fields from the first phase of the Chemistry-Climate Model Initiative (CCMI-1). Since clouds remain one of the largest uncertainties in climate projections, we simulated only clear-sky UVI. We compared the UVI climatologies obtained from CCMI and TUV against present-day climatological values of UVI derived from satellite data (the OMI-Aura OMUVBd product) and ground-based measurements (from the NDACC network). Depending on the region, relative differences between the UVI obtained from CCMI and TUV and ground-based measurements ranged between −4 % and 11 %. We calculated the UVI evolution throughout the 21st century for the four Representative Concentration Pathways (RCPs 2.6, 4.5, 6.0 and 8.5). Compared to 1960s values, we found an average increase in UVI in 2100 (of 2–4 %) in the tropical belt (30° N–30° S). For the mid-latitudes, we observed a 1.8 to 3.4 % increase in the Southern Hemisphere for RCP 2.6, 4.5 and 6.0, and found a 2.3 % decrease in RCP 8.5. Higher UV indices are projected in the Northern Hemisphere except for RCP 8.5. At high latitudes, ozone recovery is well identified and induces a complete return of mean UVI levels to 1960 values for RCP 8.5 in the Southern Hemisphere. In the Northern Hemisphere, UVI levels in 2100 are higher by 0.5 to 5.5 % for RCP 2.6, 4.5 and 6.0 and they are lower by 7.9 % for RCP 8.5. We analysed the impacts of greenhouse gases (GHGs) and ozone-depleting substances (ODSs) on UVI from 1960 by comparing CCMI sensitivity simulations (1960–2100) with fixed GHGs or ODSs at their respective 1960 levels. As expected with ODS fixed at their 1960 levels, there is no large decrease in ozone levels and consequently no sudden increase in UVI levels. With fixed GHG, we observed a delayed return of ozone to 1960 values, the same signal is observed on UVI, and looking at the UVI difference between 2090s values and 1960s values, we found an 8 % increase in the tropical belt during the summer of each hemisphere. Finally, we show that, while in the Southern Hemisphere UVI is mainly driven by total ozone column, in the Northern Hemisphere both total ozone column and aerosol optical depth drive UVI levels, with aerosol optical depth having twice as much influence on UVI as total column does.

Sign in / Sign up

Export Citation Format

Share Document