Long-term changes in aerosol radiative properties at Armilla (Spain)

2004 ◽  
Vol 38 (35) ◽  
pp. 5935-5943 ◽  
Author(s):  
H. Lyamani ◽  
F.J. Olmo ◽  
L. Alados-Arboledas
Keyword(s):  
Radiative Properties ◽  
Long Term Changes ◽  
Aerosol Radiative

scholarly journals Long-term changes in aerosol radiative properties over Ny-Ålesund: Results from Indian scientific expeditions to the Arctic

Polar Science ◽  
2021 ◽  
pp. 100700
Author(s):  
Mukunda M. Gogoi ◽  
Santosh K. Pandey ◽  
B.S. Arun ◽  
Vijayakumar S. Nair ◽  
Roseline C. Thakur ◽  
...  
Keyword(s):  
Radiative Properties ◽  
The Arctic ◽  
Long Term Changes ◽  
Aerosol Radiative

scholarly journals Global large-scale stratosphere-troposphere exchange in modern reanalyses

2016 ◽  
Author(s):  
Alexander C. Boothe ◽  
Cameron R. Homeyer
Keyword(s):  
Large Scale ◽  
Lower Stratosphere ◽  
Radiative Properties ◽  
Lapse Rate ◽  
Polar Regions ◽  
Transport Mechanisms ◽  
Upper Troposphere ◽  
Long Term Changes ◽  
The Tropics

Abstract. Stratosphere-troposphere exchange (STE) has important and significant impacts on the chemical and radiative properties of the upper troposphere and lower stratosphere. This study presents a 15-year climatology of global large-scale STE from four modern reanalyses: ERA-Interim, JRA-55, MERRA-2, and MERRA-1. STE is separated into four categories for analysis to identify the significance of known transport mechanisms: 1) vertical stratosphere-to-troposphere transport (STT), 2) vertical troposphere-to-stratosphere transport (TST), 3) lateral STT (that occurring between the tropics and the extratropics and across the tropopause "break"), and 4) lateral TST. In addition, this study employs a method to identify STE as that which crosses the lapse-rate tropopause (LRT), while most previous studies have used a potential vorticity (PV) isosurface as the troposphere-stratosphere boundary. PV-based and LRT based STE climatologies are compared using the same reanalysis output (ERA-Interim). The comparison reveals quantitative and qualitative differences, particularly in the geographic representation of TST in the polar regions. Based upon spatiotemporal integrations, we find STE to be STT-dominant in ERA-Interim and JRA-55 and TST-dominant in the MERRA reanalyses. Time series during the 15-year analysis period show long-term changes that are argued to correspond with changes in the Brewer-Dobson circulation.

scholarly journals Multidecadal trend analysis of aerosol radiative properties at a global scale

2020 ◽  
Author(s):  
Martine Collaud Coen ◽  
Elisabeth Andrews ◽  
Cathrine Lund Myhre ◽  
Jenny Hand ◽  
Marco Pandolfi ◽  
...  
Keyword(s):  
Time Series ◽  
North America ◽  
Trend Analysis ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Radiative Properties ◽  
Least Mean Square ◽  
Long Term Trend ◽  
Aerosol Radiative

<p>In order to assess the global evolution of aerosol parameters affecting climate change, a long-term trend analyses of aerosol optical properties were performed on time series from 52 stations situated across five continents. The time series of measured scattering, backscattering and absorption coefficients as well as the derived single scattering albedo, backscattering fraction, scattering and absorption Ångström exponents covered at least 10 years and up to 40 years for some stations. The non-parametric seasonal Mann-Kendall (MK) statistical test associated with several prewhitening methods and with the Sen’s slope were used as main trend analysis methods. Comparisons with General Least Mean Square associated with Autoregressive Bootstrap (GLS/ARB) and with standard Least Mean Square analysis (LMS) enabled confirmation of the detected MK statistically significant trends and the assessment of advantages and limitations of each method. Currently, scattering and backscattering coefficients trends are mostly decreasing in Europe and North America and are not statistically significant in Asia, while polar stations exhibit a mix of increasing and decreasing trends. A few increasing trends are also found at some stations in North America and Australia. Absorption coefficients time series also exhibit primarily decreasing trends. For single scattering albedo, 52% of the sites exhibit statistically significant positive trends, mostly in Asia, Eastern/Northern Europe and Arctic, 18% of sites exhibit statistically significant negative trends, mostly in central Europe and central North America, while the remaining 30% of sites have trends, which are not statistically significant. In addition to evaluating trends for the overall time series, the evolution of the trends in sequential 10 year segments was also analyzed. For scattering and backscattering, statistically significant increasing 10 year trends are primarily found for earlier periods (10 year trends ending in 2010-2015) for polar stations and Mauna Loa. For most of the stations, the present-day statistically significant decreasing 10 year trends of the single scattering albedo were preceded by not statistically significant and statistically significant increasing 10 year trends. The effect of air pollution abatement policies in continental North America is very obvious in the 10 year trends of the scattering coefficient – there is a shift to statistically significant negative trends in 2010-2011 for all stations in the eastern and central US. This long-term trend analysis of aerosol radiative properties with a broad spatial coverage enables a better global view of potential aerosol effects on climate changes.</p>

scholarly journals Multidecadal trend analysis of aerosol radiative properties at a global scale

2020 ◽  
Author(s):  
Martine Collaud Coen ◽  
Elisabeth Andrews ◽  
Andrés Alastuey ◽  
Todor Petkov Arsov ◽  
John Backman ◽  
...  
Keyword(s):  
Time Series ◽  
North America ◽  
Trend Analysis ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Radiative Properties ◽  
Least Mean Square ◽  
Long Term Trend ◽  
Aerosol Radiative

Abstract. In order to assess the global evolution of aerosol parameters affecting climate change, a long-term trend analyses of aerosol optical properties were performed on time series from 52 stations situated across five continents. The time series of measured scattering, backscattering and absorption coefficients as well as the derived single scattering albedo, backscattering fraction, scattering and absorption Ångström exponents covered at least 10 years and up to 40 years for some stations. The non-parametric seasonal Mann–Kendall (MK) statistical test associated with several prewhitening methods and with the Sen's slope were used as main trend analysis methods. Comparisons with General Least Mean Square associated with Autoregressive Bootstrap (GLS/ARB) and with standard Least Mean Square analysis (LMS) enabled confirmation of the detected MK statistically significant trends and the assessment of advantages and limitations of each method. Currently, scattering and backscattering coefficients trends are mostly decreasing in Europe and North America and are not statistically significant in Asia, while polar stations exhibit a mix of increasing and decreasing trends. A few increasing trends are also found at some stations in North America and Australia. Absorption coefficients time series also exhibit primarily decreasing trends. For single scattering albedo, 52 % of the sites exhibit statistically significant positive trends, mostly in Asia, Eastern/Northern Europe and Arctic, 18 % of sites exhibit statistically significant negative trends, mostly in central Europe and central North America, while the remaining 30 % of sites have trends, which are not statistically significant. In addition to evaluating trends for the overall time series, the evolution of the trends in sequential 10 year segments was also analyzed. For scattering and backscattering, statistically significant increasing 10 year trends are primarily found for earlier periods (10 year trends ending in 2010–2015) for polar stations and Mauna Loa. For most of the stations, the present-day statistically significant decreasing 10 year trends of the single scattering albedo were preceded by not statistically significant and statistically significant increasing 10 year trends. The effect of air pollution abatement policies in continental North America is very obvious in the 10 year trends of the scattering coefficient – there is a shift to statistically significant negative trends in 2010–2011 for all stations in the eastern and central US. This long-term trend analysis of aerosol radiative properties with a broad spatial coverage enables a better global view of potential aerosol effects on climate changes.

scholarly journals Aerosol radiative effects in the ultraviolet, visible, and near-infrared spectral ranges using long-term aerosol data series over the Iberian Peninsula

2014 ◽  
Vol 14 (7) ◽  
pp. 8779-8818 ◽  
Author(s):  
D. Mateos ◽  
M. Antón ◽  
C. Toledano ◽  
V. E. Cachorro ◽  
L. Alados-Arboledas ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Near Infrared ◽  
Radiative Properties ◽  
Radiative Effects ◽  
Spectral Ranges ◽  
Aerosol Radiative Effects ◽  
Aerosol Radiative

Abstract. A better understanding of the aerosol radiative properties is a crucial challenge for climate change studies. This study aims to provide a complete characterization of aerosol radiative effects in different spectral ranges within the shortwave (SW) solar spectrum. For this purpose, long-term datasets of aerosol properties from six AERONET stations located in the Iberian Peninsula (Southwestern Europe) are analyzed in term of climatology characterization and trends. Aerosol information is used as input to the libRadtran model in order to determine the aerosol radiative effect at the surface in the ultraviolet (AREUV), visible (AREVIS), near-infrared (ARENIR), and the entire SW range (ARESW) under cloud-free conditions. Over the whole Iberian Peninsula, aerosol radiative effects in the different spectral ranges are: −1.1 < AREUV < −0.7 W m−2, −5.7 < AREVIS < −3.8 W m−2, −2.8 < ARENIR < −1.7 W m−2, and −9.5 < ARESW < −6.1 W m−2. The four variables showed positive statistically significant trends between 2004 and 2012, e.g., ARESW increased +3.6 W m−2 per decade. This fact is linked to the decrease in the aerosol load, which presents a trend of −0.04 per unit of aerosol optical depth at 500 nm per decade, hence a reduction of aerosol effect on solar radiation at the surface is seen. Monthly means of ARE show a seasonal pattern with larger values in spring and summer. The aerosol forcing efficiency (AFE), ARE per unit of aerosol optical depth, is also evaluated in the four spectral ranges. AFE exhibits a dependence on single scattering albedo and a weaker one on Ångström exponent. AFE is larger (in absolute value) for small and absorbing particles. The contributions of the UV, VIS, and NIR ranges to the SW efficiency vary with the aerosol types. Aerosol size determines the fractions of AFEVIS/AFESW and AFENIR/AFESW. VIS range is the dominant region for all types, although non-absorbing large particles cause a more equal contribution of VIS and NIR intervals. The AFEUV / AFESW ratio shows a higher contribution for absorbing fine particles.

scholarly journals Multidecadal trend analysis of in situ aerosol radiative properties around the world

2020 ◽  
Vol 20 (14) ◽  
pp. 8867-8908 ◽  
Author(s):  
Martine Collaud Coen ◽  
Elisabeth Andrews ◽  
Andrés Alastuey ◽  
Todor Petkov Arsov ◽  
John Backman ◽  
...  
Keyword(s):  
Time Series ◽  
North America ◽  
Trend Analysis ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Radiative Properties ◽  
Least Mean Square ◽  
Long Term Trend ◽  
Aerosol Radiative

Abstract. In order to assess the evolution of aerosol parameters affecting climate change, a long-term trend analysis of aerosol optical properties was performed on time series from 52 stations situated across five continents. The time series of measured scattering, backscattering and absorption coefficients as well as the derived single scattering albedo, backscattering fraction, scattering and absorption Ångström exponents covered at least 10 years and up to 40 years for some stations. The non-parametric seasonal Mann–Kendall (MK) statistical test associated with several pre-whitening methods and with Sen's slope was used as the main trend analysis method. Comparisons with general least mean square associated with autoregressive bootstrap (GLS/ARB) and with standard least mean square analysis (LMS) enabled confirmation of the detected MK statistically significant trends and the assessment of advantages and limitations of each method. Currently, scattering and backscattering coefficient trends are mostly decreasing in Europe and North America and are not statistically significant in Asia, while polar stations exhibit a mix of increasing and decreasing trends. A few increasing trends are also found at some stations in North America and Australia. Absorption coefficient time series also exhibit primarily decreasing trends. For single scattering albedo, 52 % of the sites exhibit statistically significant positive trends, mostly in Asia, eastern/northern Europe and the Arctic, 22 % of sites exhibit statistically significant negative trends, mostly in central Europe and central North America, while the remaining 26 % of sites have trends which are not statistically significant. In addition to evaluating trends for the overall time series, the evolution of the trends in sequential 10-year segments was also analyzed. For scattering and backscattering, statistically significant increasing 10-year trends are primarily found for earlier periods (10-year trends ending in 2010–2015) for polar stations and Mauna Loa. For most of the stations, the present-day statistically significant decreasing 10-year trends of the single scattering albedo were preceded by not statistically significant and statistically significant increasing 10-year trends. The effect of air pollution abatement policies in continental North America is very obvious in the 10-year trends of the scattering coefficient – there is a shift to statistically significant negative trends in 2009–2012 for all stations in the eastern and central USA. This long-term trend analysis of aerosol radiative properties with a broad spatial coverage provides insight into potential aerosol effects on climate changes.

scholarly journals Aerosol radiative effects in the ultraviolet, visible, and near-infrared spectral ranges using long-term aerosol data series over the Iberian Peninsula

2014 ◽  
Vol 14 (24) ◽  
pp. 13497-13514 ◽  
Author(s):  
D. Mateos ◽  
M. Antón ◽  
C. Toledano ◽  
V. E. Cachorro ◽  
L. Alados-Arboledas ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Near Infrared ◽  
Fine Particles ◽  
Radiative Properties ◽  
Radiative Effects ◽  
Spectral Ranges ◽  
Aerosol Radiative Effects ◽  
Aerosol Types ◽  
Aerosol Radiative

Abstract. A better understanding of aerosol radiative properties is a crucial challenge for climate change studies. This study aims at providing a complete characterization of aerosol radiative effects in different spectral ranges within the shortwave (SW) solar spectrum. For this purpose, long-term data sets of aerosol properties from six AERONET stations located in the Iberian Peninsula (southwestern Europe) have been analyzed in terms of climatological characterization and inter-annual changes. Aerosol information was used as input for the libRadtran model in order to determine the aerosol radiative effect (ARE) at the surface in the ultraviolet (AREUV), visible (AREVIS), near-infrared (ARENIR), and the entire SW range (ARESW) under cloud-free conditions. Over the whole Iberian Peninsula, yearly aerosol radiative effects in the different spectral ranges were found to be −1.1 < AREUV < −0.7, −5.7 < AREVIS < −3.5, −2.6 < ARENIR < −1.6, and −8.8 < ARESW < −5.7 (in W m−2). Monthly means of ARE showed a seasonal pattern with larger values in spring and summer. The aerosol forcing efficiency (AFE), ARE per unit of aerosol optical depth, has also been evaluated in the four spectral ranges. AFE exhibited a dependence on single scattering albedo as well as a weaker one on the Ångström exponent. AFE is larger (in absolute value) for small and absorbing particles. The contributions of the UV, VIS, and NIR ranges to the SW efficiency varied with the aerosol types. The predominant aerosol size determined the fractions AFEVIS/AFESW and AFENIR/AFESW. The AFEVIS was the dominant contributor for all aerosol types, although non-absorbing large particles caused more even contribution of VIS and NIR intervals. The AFEUV / AFESW ratio showed a higher value in the case of absorbing fine particles.

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