Decadal variability of aerosol optical depth in Europe and its relationship to the temporal shift of the North Atlantic Oscillation in the realm of dimming and brightening

Chiacchio, Marc; Ewen, Tracy; Wild, Martin; Chin, Mian; Diehl, Thomas

doi:10.1029/2010jd014471

Cited by 35 publications

(44 citation statements)

References 65 publications

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“…The insignificant trend of −8 % ± 5 % per decade observed at Uccle lies within the range of trends observed at other European stations. The long-term τ aer decrease over much of Europe is quite consistent with the supposed reversal from increasing to decreasing anthropogenic sulfur and black carbon emissions owing to the enactment of clean-air legislation in many countries (Mishchenko and Geogdzhayev, 2007;Chiaccio et al, 2011;Alpert et al, 2012;de Meij et al, 2012;Hsu et al, 2012;Nabat et al, 2013). This change occurred after 1988-1989, the time period when a maximum was reached in the emissions of sulfate aerosols over Europe (Chiaccio et al, 2011).…”

Section: Aerosol Optical Depth At 3201 Nmsupporting

confidence: 51%

“…The long-term τ aer decrease over much of Europe is quite consistent with the supposed reversal from increasing to decreasing anthropogenic sulfur and black carbon emissions owing to the enactment of clean-air legislation in many countries (Mishchenko and Geogdzhayev, 2007;Chiaccio et al, 2011;Alpert et al, 2012;de Meij et al, 2012;Hsu et al, 2012;Nabat et al, 2013). This change occurred after 1988-1989, the time period when a maximum was reached in the emissions of sulfate aerosols over Europe (Chiaccio et al, 2011). Many scientists believe that the decadal changes in aerosols have influenced the amount of solar radiation reaching the surface of the Earth and that the decrease in aerosols has played a part in the switch from global dimming to global brightening, which occurred around 1980-1990(Augustine et al, 2008Chiaccio et al, 2011).…”

Section: Aerosol Optical Depth At 3201 Nmmentioning

confidence: 52%

“…This change occurred after 1988-1989, the time period when a maximum was reached in the emissions of sulfate aerosols over Europe (Chiaccio et al, 2011). Many scientists believe that the decadal changes in aerosols have influenced the amount of solar radiation reaching the surface of the Earth and that the decrease in aerosols has played a part in the switch from global dimming to global brightening, which occurred around 1980-1990(Augustine et al, 2008Chiaccio et al, 2011). According to , the reduction of aerosols may have played a role during the 1990s but not after 2000.…”

Section: Aerosol Optical Depth At 3201 Nmmentioning

confidence: 99%

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Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

et al. 2014

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Abstract. At Uccle, Belgium, a long time series of simultaneous measurements of erythemal ultraviolet (UV) dose (S ery ), global solar radiation (S g ), total ozone column (Q O 3 ) and aerosol optical depth (τ aer ) (at 320.1 nm) is available, which allows for an extensive study of the changes in the variables over time. Linear trends were determined for the different monthly anomalies time series. S ery , S g and Q O 3 all increase by respectively 7, 4 and 3 % per decade. τ aer shows an insignificant negative trend of −8 % per decade. These trends agree with results found in the literature for sites with comparable latitudes. A change-point analysis, which determines whether there is a significant change in the mean of the time series, is applied to the monthly anomalies time series of the variables. Only for S ery and Q O 3 , was a significant change point present in the time series around February 1998 and March 1998, respectively. The change point in Q O 3 corresponds with results found in the literature, where the change in ozone levels around 1997 is attributed to the recovery of ozone. A multiple linear regression (MLR) analysis is applied to the data in order to study the influence of S g , Q O 3 and τ aer on S ery . Together these parameters are able to explain 94 % of the variation in S ery . Most of the variation (56 %) in S ery is explained by S g . The regression model performs well, with a slight tendency to underestimate the measured S ery values and with a mean absolute bias error (MABE) of 18 %. However, in winter, negative S ery are modeled. Applying the MLR to the individual seasons solves this issue. The seasonal models have an adjusted R 2 value higher than 0.8 and the correlation between modeled and measured S ery values is higher than 0.9 for each season. The summer model gives the best performance, with an absolute mean error of only 6 %. However, the seasonal regression models do not always represent reality, where an increase in S ery is accompanied with an increase in Q O 3 and a decrease in τ aer . In all seasonal models, S g is the factor that contributes the most to the variation in S ery , so there is no doubt about the necessity to include this factor in the regression models. The individual contribution of τ aer to S ery is very low, and for this reason it seems unnecessary to include τ aer in the MLR analysis. Including Q O 3 , however, is justified to increase the adjusted R 2 and to decrease the MABE of the model.

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Section: Aerosol Optical Depth At 3201 Nmsupporting

confidence: 51%

Section: Aerosol Optical Depth At 3201 Nmmentioning

confidence: 52%

Section: Aerosol Optical Depth At 3201 Nmmentioning

confidence: 99%

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Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

et al. 2014

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“…This mechanism, however, is not confirmed by either GISS-E2 or NCAR-CESM1, and is therefore not robust and requires future investigation. Previous work relating aerosol forcing to North Atlantic circulation (Chiacchio et al, 2011;FischerBruns et al, 2009, Allen andSherwood, 2012) has been limited to single models and results have been inconclusive across studies. The impact of aerosols on the North Atlantic and Mediterranean climate (and the NAO) thus remains unclear, and 30 may warrant additional work with a larger model ensemble, with the diagnostics needed to probe the driving mechanisms more deeply, and to assess robustness in a more rigorous manner.…”

Section: Discussionmentioning

confidence: 99%

Connecting regional aerosol emissions reductions to local and remote precipitation responses

Westervelt¹,

Conley²,

Fiore³

et al. 2018

Preprint

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“…In that study greenhouse gas forcing was shown to be connected to the long-term downward trend in the amplitude of the annual cycle since 1950, whereas aerosol forcing was related to a nonlinear response, possibly in connection to the global dimming/brightening phenomenon (Wild 2009). However, in general the separation of aerosol forcing from atmospheric circulation variability is confounded by a broadly common trend throughout the latter decades of the twentieth century across the Northern Hemisphere in the aerosol-induced dimming and brightening effects and the North Atlantic Oscillation (NAO) and NAM (Chiacchio and Wild 2010;Chiacchio et al 2011). Furthermore, as pointed out by Qian and Zhang (2015), the signal-to-noise ratio in the amplitude of the annual cycle is much lower than is typically found in trends of mean temperature as a result of the same sign of signals in the winter and summer seasons.…”

Section: Introductionmentioning

confidence: 99%

Twentieth-Century Trends in the Annual Cycle of Temperature across the Northern Hemisphere

2017

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The annual cycle of surface air temperature is examined across Northern Hemisphere land areas (north of 258N) by comparing the results from the Climatic Research Unit Time Series (CRU TS) dataset against four reanalysis datasets: two versions of the NOAA Twentieth Century Reanalysis (20CR and 20CRC) and two versions of the ECMWF Twentieth Century Reanalysis, version 2 (ERA-20C) and version 2c (ERA-20CM). The modulated annual cycle is adaptively derived from an ensemble empirical mode decomposition (EEMD) filter, and is used to define the phase and amplitude of the annual cycle. The EEMD method does not impose a simple sinusoidal shape of the annual cycle. None of the reanalysis simulations assimilates surface temperature or land-use data. However, they differ in the parameters that are included: both ERA-20C and 20CR assimilate surface pressure data; ERA-20C also includes surface wind data over the oceans; and ERA-20CM does not assimilate any of these synoptic data. It is demonstrated that synoptic variability is critical for explaining the trends and variability of the annual cycle of surface temperature across the Northern Hemisphere. The CMIP5 forcings alone are insufficient to explain the observed trends and decadal-scale variability, particularly with respect to the decline in the amplitude of the annual cycle throughout the twentieth century. The variability in the annual cycle during the latter half of the twentieth century was unusual in the context of the twentieth century, and was most likely related to large-scale atmospheric variability, although uncertainty in the results is greatest before about 1930.

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Decadal variability of aerosol optical depth in Europe and its relationship to the temporal shift of the North Atlantic Oscillation in the realm of dimming and brightening

Cited by 35 publications

References 65 publications

Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

Connecting regional aerosol emissions reductions to local and remote precipitation responses

Twentieth-Century Trends in the Annual Cycle of Temperature across the Northern Hemisphere

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