scholarly journals Radiative forcing from the 1991 Mount Pinatubo volcanic eruption

1998 ◽  
Vol 103 (D12) ◽  
pp. 13837-13857 ◽  
Author(s):  
Georgiy L. Stenchikov ◽  
Ingo Kirchner ◽  
Alan Robock ◽  
Hans-F. Graf ◽  
Juan Carlos Antuña ◽  
...  
2015 ◽  
Vol 33 (7) ◽  
pp. 789-804 ◽  
Author(s):  
A. Réchou ◽  
S. Kirkwood

Abstract. Temperature, precipitation and sunshine duration measurements at meteorological stations across the southern Indian Ocean have been analysed to try to differentiate the possible influence of the Mount Pinatubo volcanic eruption in the Philippines in June 1991 and the normal weather forcings. During December 1991, precipitation on the tropical islands Glorieuses (11.6° S) and Mayotte (12.8° S) was 4 and 3 times greater, respectively, than the climatological mean (precipitation is greater by more than than twice the standard deviation (SD)). Mean sunshine duration (expressed in sun hours per day) was only 6 h on Mayotte, although the sunshine duration is usually more than 7.5 ± 0.75 h, and on the Glorieuses it was only 5 h, although it is usually 8.5 ± 1 h. Mean and SD of sunshine duration are based on December (1964–2001 for Mayotte, 1966–1999 for the Glorieuses). The Madden–Julian Oscillation (MJO) is shown to correlate best with precipitation in this area. Variability controlling the warm zone on these two islands can be increased by the Indian Ocean Dipole (IOD), El Niño, the quasi-biennial oscillation (QBO) and/or solar activity (sunspot number, SSN). However, temperature records of these two islands show weak dependence on such forcings (temperatures are close to the climatological mean for December). This suggests that such weather forcings have an indirect effect on the precipitation. December 1991 was associated with unusually low values of the MJO index, which favours high rainfall, as well as with El Niño, eastern QBO and high SSN, which favour high variability. It is therefore not clear whether the Mount Pinatubo volcanic eruption had an effect. Since the precipitation anomalies at the Glorieuses and Mayotte are more or less local (Global Precipitation Climatology Project (GPCP) data) and the effect of the Pinatubo volcanic cloud should be more widespread, it seems unlikely that Pinatubo was the cause. Islands at higher southern latitudes (south of Tromelin at 15.5° S) were not affected by the Pinatubo eruption in terms of sunshine duration, precipitation or temperature.


2016 ◽  
Vol 16 (1) ◽  
pp. 305-323 ◽  
Author(s):  
A. Laakso ◽  
H. Kokkola ◽  
A.-I. Partanen ◽  
U. Niemeier ◽  
C. Timmreck ◽  
...  

Abstract. Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an Earth system model to study the radiative and climate changes occurring after an erupting volcano during solar radiation management (SRM). According to our simulations the radiative impacts of the eruption and SRM are not additive and the radiative effects and climate changes occurring after the eruption depend strongly on whether SRM is continued or suspended after the eruption. In the former case, the peak burden of the additional stratospheric sulfate as well as changes in global mean precipitation are fairly similar regardless of whether the eruption takes place in a SRM or non-SRM world. However, the maximum increase in the global mean radiative forcing caused by the eruption is approximately 21 % lower compared to a case when the eruption occurs in an unperturbed atmosphere. In addition, the recovery of the stratospheric sulfur burden and radiative forcing is significantly faster after the eruption, because the eruption during the SRM leads to a smaller number and larger sulfate particles compared to the eruption in a non-SRM world. On the other hand, if SRM is suspended immediately after the eruption, the peak increase in global forcing caused by the eruption is about 32 % lower compared to a corresponding eruption into a clean background atmosphere. In this simulation, only about one-third of the global ensemble-mean cooling occurs after the eruption, compared to that occurring after an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal is seen only for the 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of global precipitation rate, we obtain a 36 % smaller decrease in the first year after the eruption and again a clearly faster recovery in the concurrent eruption and SRM scenario, which is suspended after the eruption. We also found that an explosive eruption could lead to significantly different regional climate responses depending on whether it takes place during geoengineering or into an unperturbed background atmosphere. Our results imply that observations from previous large eruptions, such as Mount Pinatubo in 1991, are not directly applicable when estimating the potential consequences of a volcanic eruption during stratospheric geoengineering.


2016 ◽  
Vol 16 (11) ◽  
pp. 6841-6861 ◽  
Author(s):  
Pasquale Sellitto ◽  
Alcide di Sarra ◽  
Stefano Corradini ◽  
Marie Boichu ◽  
Hervé Herbin ◽  
...  

Abstract. In this paper we combine SO2 and ash plume dispersion modelling with satellite and surface remote sensing observations to study the regional influence of a relatively weak volcanic eruption from Mount Etna on the optical and micro-physical properties of Mediterranean aerosols. We analyse the Mount Etna eruption episode of 25–27 October 2013. The evolution of the plume along the trajectory is investigated by means of the FLEXible PARTicle Lagrangian dispersion (FLEXPART) model. The satellite data set includes true colour images, retrieved values of volcanic SO2 and ash, estimates of SO2 and ash emission rates derived from MODIS (MODerate resolution Imaging Spectroradiometer) observations and estimates of cloud top pressure from SEVIRI (Spinning Enhanced Visible and InfraRed Imager). Surface remote sensing measurements of aerosol and SO2 made at the ENEA Station for Climate Observations (35.52° N, 12.63° E; 50 m a.s.l.) on the island of Lampedusa are used in the analysis. The combination of these different data sets suggests that SO2 and ash, despite the initial injection at about 7.0 km altitude, reached altitudes around 10–12 km and influenced the column average aerosol particle size distribution at a distance of more than 350 km downwind. This study indicates that even a relatively weak volcanic eruption may produce an observable effect on the aerosol properties at the regional scale. The impact of secondary sulfate particles on the aerosol size distribution at Lampedusa is discussed and estimates of the clear-sky direct aerosol radiative forcing are derived. Daily shortwave radiative forcing efficiencies, i.e. radiative forcing per unit AOD (aerosol optical depth), are calculated with the LibRadtran model. They are estimated between −39 and −48 W m−2 AOD−1 at the top of the atmosphere and between −66 and −49 W m−2 AOD−1 at the surface, with the variability in the estimates mainly depending on the aerosol single scattering albedo. These results suggest that sulfate particles played a large role in the transported plume composition and radiative forcing, while the contribution by ash particles was small in the volcanic plume arriving at Lampedusa during this event.


2015 ◽  
Vol 15 (21) ◽  
pp. 31335-31383 ◽  
Author(s):  
P. Sellitto ◽  
A. di Sarra ◽  
S. Corradini ◽  
M. Boichu ◽  
H. Herbin ◽  
...  

Abstract. In this paper we combine SO2/ash plume dispersion modelling, satellite and surface remote sensing observations to study the regional influence of a relatively weak volcanic eruption from Mount Etna on the optical and micro-physical properties of Mediterranean aerosols. We analyse the Mount Etna eruption episode of 25–27 October 2013. The evolution of the plume along the trajectory is investigated by means of the FLEXPART (FLEXible PARTicle dispersion model) Lagrangian dispersion model. The satellite dataset includes true colour images, retrieved values of volcanic SO2 and ash, and estimates of SO2 and ash emission rates derived from MODIS (MODerate resolution Imaging Spectroradiometer) observations, and estimates of cloud top pressure from SEVIRI (Spinning Enhanced Visible and InfraRed Imager). Surface remote sensing measurements of aerosol and SO2 made at the ENEA Station for Climate Observations (35.52° N, 12.63° E, 50 m a.s.l.) on the island of Lampedusa are used in the analysis. The combination of these different datasets suggests that SO2 and ash, despite the initial injection occurred at about 7.0 km altitude, reached altitudes around 10–12 km and influenced the aerosol size distribution at a distance more than 350 km downwind. This study indicates that even a relatively weak volcanic eruption may produce an observable effect on the aerosol properties at the regional scale. The impact of secondary sulphate particles on the aerosol size distribution at Lampedusa is discussed, and estimates of the clear sky direct aerosol radiative forcing are derived. Daily shortwave radiative forcing efficiencies are calculated with the LibRadtran model. They are estimated between −39 and −48 W m−2 AOD−1 at the top of the atmosphere, and between −66 and −49 W m−2 AOD−1, at the surface, with the variability in the estimates mainly depending on the aerosol single scattering albedo. These results suggest that sulphate particles played a large role, while the contribution by ash particles was small in the volcanic plume arriving at Lampedusa during this event.


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