scholarly journals Surface temperature response to the major volcanic eruptions in multiple reanalysis data sets

2019 ◽  
Author(s):  
Masatomo Fujiwara ◽  
Patrick Martineau ◽  
Jonathon S. Wright

Abstract. The global response of air temperature at 2 metre above the surface to the eruptions of Mount Agung in March 1963, El Chichón in April 1982, and Mount Pinatubo in June 1991 is investigated using 11 global atmospheric reanalysis data sets (JRA-55, JRA-25, MERRA-2, MERRA, ERA-Interim, ERA-40, CFSR, NCEP-NCAR R-1, 20CR version 2c, ERA-20C, and CERA-20C). Multiple linear regression (MLR) is applied to the monthly mean time series of temperature for two periods, 1980–2010 (for 10 reanalyses) and 1958–2001 (for six reanalyses), by considering explanatory factors of seasonal harmonics, linear trends, Quasi-Biennial Oscillation (QBO), solar cycle, tropical sea surface temperature (SST) variations in the Pacific, Indian, and Atlantic Oceans, and Arctic SST variations. Empirical orthogonal function (EOF) analysis is applied to these climatic indices to obtain a set of orthogonal indices to be used for the MLR. The residuals of the MLR are used to define the volcanic signals for the three eruptions separately. First, latitudinally averaged time series of the residuals are investigated and compared with the results from previous studies. Then, the geographical distribution of the response during the peak cooling period after each eruption is investigated. In general, different reanalyses show similar geographical patterns of the response, but with the largest differences in the polar regions. The Pinatubo response shows largest average cooling in the 60° N–60° S region among the three eruptions, with a peak cooling of 0.10–0.15 K. The El Chichón response shows slightly larger cooling in the NH than in the Southern Hemisphere (SH), while the Agung response shows larger cooling in the SH. These hemispheric differences are consistent with the distribution of stratospheric aerosol optical depth after these eruptions; however, the peak cooling after these two eruptions is comparable in magnitude to unexplained cooling events in other periods without volcanic influence. Other methods in which the MLR model is used with different sets of indices are also tested, and it is found that careful treatment of tropical SST variability is necessary to evaluate the surface response to volcanic eruptions in observations and reanalyses.

2020 ◽  
Vol 20 (1) ◽  
pp. 345-374
Author(s):  
Masatomo Fujiwara ◽  
Patrick Martineau ◽  
Jonathon S. Wright

Abstract. The global response of air temperature at 2 m above the surface to the eruptions of Mount Agung in March 1963, El Chichón in April 1982, and Mount Pinatubo in June 1991 is investigated using 11 global atmospheric reanalysis data sets (JRA-55, JRA-25, MERRA-2, MERRA, ERA-Interim, ERA-40, CFSR, NCEP-NCAR R-1, 20CR version 2c, ERA-20C, and CERA-20C). Multiple linear regression (MLR) is applied to the monthly mean time series of temperature for two periods – 1980–2010 (for 10 reanalyses) and 1958–2001 (for 6 reanalyses) – by considering explanatory factors of seasonal harmonics, linear trends, quasi-biennial oscillation (QBO), solar cycle, tropical sea surface temperature (SST) variations in the Pacific, Indian, and Atlantic Oceans, and Arctic SST variations. Empirical orthogonal function (EOF) analysis is applied to these climatic indices to obtain a set of orthogonal indices to be used for the MLR. The residuals of the MLR are used to define the volcanic signals for the three eruptions separately. First, area-averaged time series of the residuals are investigated and compared with the results from previous studies. Then, the geographical distribution of the response during the peak cooling period after each eruption is investigated. In general, different reanalyses show similar geographical patterns of the response, but with the largest differences in the polar regions. The Pinatubo response shows the largest average cooling in the 60∘ N–60∘ S region among the three eruptions, with a peak cooling of 0.10–0.15 K. The El Chichón response shows slightly larger cooling in the NH than in the Southern Hemisphere (SH), while the Agung response shows larger cooling in the SH. These hemispheric differences are consistent with the distribution of stratospheric aerosol optical depth after these eruptions; however, the peak cooling after these two eruptions is comparable in magnitude to unexplained cooling events in other periods without volcanic influence. Other methods in which the MLR model is used with different sets of indices are also tested, and it is found that careful treatment of tropical SST variability is necessary to evaluate the surface response to volcanic eruptions in observations and reanalyses.


2016 ◽  
Author(s):  
Cristen Adams ◽  
Adam E. Bourassa ◽  
Chris A. McLinden ◽  
Chris E. Sioris ◽  
Thomas von Clarmann ◽  
...  

Abstract. Following the large volcanic eruptions of Pinatubo in 1991 and El Chichón in 1982, decreases in stratospheric NO2 associated with enhanced aerosol were observed. The Optical Spectrograph and InfraRed Imaging Spectrometer (OSIRIS) likewise measured widespread enhancements of stratospheric aerosol following seven volcanic eruptions between 2002 and 2014, although the magnitudes of these eruptions were all much smaller than the Pinatubo and El Chichón eruptions. In order to isolate and quantify the relationship between volcanic aerosol and NO2, NO2 anomalies were calculated using measurements from OSIRIS and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). In the tropics, variability due to the quasi-biennial oscillation was subtracted from the timeseries. OSIRIS profile measurements indicate that the strongest relationships between NO2 and volcanic aerosol extinction were for the layer ~ 3–7 km above the tropopause, where OSIRIS stratospheric NO2 partial columns for ~ 3–7 km above the tropopause were found to be smaller than baseline levels during these aerosol enhancements by up to ~ 60 % with typical Pearson correlation coefficients of R ~ −0.7. MIPAS also observed decreases in NO2 partial columns during periods of affected by volcanic aerosol, with percent differences of up to ~ 25 %. An even stronger relationship was observed between OSIRIS aerosol optical depth and MIPAS N2O5 partial columns, with R ~ −0.9, although no link with MIPAS HNO3 was observed. The variation of OSIRIS NO2 with increasing aerosol was found to be quantitatively consistent with simulations from a photochemical box model in terms of both magnitude and degree of non-linearity.


2017 ◽  
Vol 17 (13) ◽  
pp. 8063-8080 ◽  
Author(s):  
Cristen Adams ◽  
Adam E. Bourassa ◽  
Chris A. McLinden ◽  
Chris E. Sioris ◽  
Thomas von Clarmann ◽  
...  

Abstract. Following the large volcanic eruptions of Pinatubo in 1991 and El Chichón in 1982, decreases in stratospheric NO2 associated with enhanced aerosol were observed. The Optical Spectrograph and Infrared Imaging Spectrometer (OSIRIS) measured the widespread enhancements of stratospheric aerosol following seven volcanic eruptions between 2002 and 2014, although the magnitudes of these eruptions were all much smaller than the Pinatubo and El Chichón eruptions. In order to isolate and quantify the relationship between volcanic aerosol and NO2, NO2 anomalies were calculated using measurements from OSIRIS and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). In the tropics, variability due to the quasi-biennial oscillation was subtracted from the time series. OSIRIS profile measurements indicate that the strongest anticorrelations between NO2 and volcanic aerosol extinction were for the 5 km layer starting  ∼  3 km above the climatological mean tropopause at the given latitude. OSIRIS stratospheric NO2 partial columns in this layer were found to be smaller than background NO2 levels during these aerosol enhancements by up to  ∼  60 % with typical Pearson correlation coefficients of R ∼ −0. 7. MIPAS also observed decreases in NO2 partial columns during periods affected by volcanic aerosol, with percent differences of up to  ∼  25 % relative to background levels. An even stronger anticorrelation was observed between OSIRIS aerosol optical depth and MIPAS N2O5 partial columns, with R ∼ −0. 9, although no link with MIPAS HNO3 was observed. The variation in OSIRIS NO2 with increasing aerosol was found to be consistent with simulations from a photochemical box model within the estimated model uncertainty.


2015 ◽  
Vol 15 (9) ◽  
pp. 13315-13346 ◽  
Author(s):  
M. Fujiwara ◽  
T. Hibino ◽  
S. K. Mehta ◽  
L. Gray ◽  
D. Mitchell ◽  
...  

Abstract. Global temperature response to the eruptions of Mount Agung in 1963, El Chichón in 1982 and Mount Pinatubo in 1991 is investigated using nine reanalysis datasets (JRA-55, MERRA, ERA-Interim, NCEP-CFSR, JRA-25, ERA-40, NCEP-1, NCEP-2, and 20CR). Multiple linear regression is applied to the zonal and monthly mean time series of temperature for two periods, 1979–2009 (for eight reanalysis datasets) and 1958–2001 (for four reanalysis datasets), by considering explanatory factors of seasonal harmonics, linear trends, Quasi-Biennial Oscillation, solar cycle, and El Niño Southern Oscillation. The residuals are used to define the volcanic signals for the three eruptions separately. In response to the Mount Pinatubo eruption, most reanalysis datasets show strong warming signals (up to 2–3 K for one-year average) in the tropical lower stratosphere and weak cooling signals (down to −1 K) in the subtropical upper troposphere. For the El Chichón eruption, warming signals in the tropical lower stratosphere are somewhat smaller than those for the Mount Pinatubo eruption. The response to the Mount Agung eruption is asymmetric about the equator with strong warming in the Southern Hemisphere midlatitude upper troposphere to lower stratosphere. The response to three other smaller-scale eruptions in the 1960s and 1970s is also investigated. Comparison of the results from several different reanalysis datasets confirms the atmospheric temperature response to these major eruptions qualitatively, but also shows quantitative differences even among the most recent reanalysis datasets.


1984 ◽  
Vol 23 (2) ◽  
pp. 223-232
Author(s):  
K. Labitzke ◽  
B. Naujokat

Durante el verano y el otoño de 1982, y también durante el verano y otoño de 1963, la temperatura a 30 mbar subió más de tres desviaciones estándar sobre el promedio de 18 años en latitudes tropicales. Estos calentamientos se atribuyen a los aerosoles estratosféricos producidos por las erupciones del Monte Agung en marzo de 1963 y El Chichón en abril de 1982.


2006 ◽  
Vol 19 (12) ◽  
pp. 2984-2994 ◽  
Author(s):  
James K. Angell

Abstract The mean monthly polar stereographic map analyses of the Free University of Berlin terminated at the end of 2001. This paper summarizes the changes in size of the 300-mb north circumpolar vortex, and quadrants, for the full period of record, 1963–2001, where the size has been defined by planimetering the area poleward of contours in the jet stream core. A contracted vortex has tended to be a deep vortex in winter but a shallow vortex in summer. During 1963–2001 there was a statistically significant decrease in vortex size of 1.5% per decade, the decrease in size of Western Hemisphere quadrants being twice that of Eastern Hemisphere quadrants. A significant increase in Arctic Oscillation (AO) index accompanies the significant decrease in vortex size, but since the vortex contracts appreciably in all four seasons, whereas the positive trend in the AO index is mainly in winter, the vortex cannot serve as a proxy for the AO index. The evidence for vortex contraction at the time of the 1976–77 regime shift is not conclusive, but there is good evidence for a 6% increase in vortex size due to the 1991 Pinatubo eruption. There is little change in vortex size following the 1982 El Chichon eruption, however. Because on average there is a significant 4% contraction of the vortex following an El Niño, it is proposed that the vortex expansion to be expected following the 1982 El Chichon eruption has been contravened by the contraction following the strong 1982–83 El Niño. There is little relation between vortex size and phase of the quasi-biennial oscillation (QBO), and the evidence for a contracted vortex near 11-yr sunspot maxima is tenuous because the vortex record extends through only three full sunspot cycles. There is a highly significant tendency for opposite vortex quadrants 0°–90°E and 90°W–180° to vary in size together, indicating either a pulsating polar vortex or the propagation of planetary wavenumber 2.


2016 ◽  
Vol 29 (4) ◽  
pp. 1325-1338 ◽  
Author(s):  
A. Meyer ◽  
D. Folini ◽  
U. Lohmann ◽  
T. Peter

Abstract Tropical land mean surface air temperature and precipitation responses to the eruptions of El Chichón in 1982 and Pinatubo in 1991, as simulated by the atmosphere-only GCMs (AMIP) in phase 5 of the Coupled Model Intercomparison Project (CMIP5), are examined and compared to three observational datasets. The El Niño–Southern Oscillation (ENSO) signal was statistically separated from the volcanic signal in all time series. Focusing on the ENSO signal, it was found that the 17 investigated AMIP models successfully simulate the observed 4-month delay in the temperature responses to the ENSO phase but simulate somewhat too-fast precipitation responses during the El Niño onset stage. The observed correlation between temperature and ENSO phase (correlation coefficient of 0.75) is generally captured well by the models (simulated correlation of 0.71 and ensemble means of 0.61–0.83). For precipitation, mean correlations with the ENSO phase are −0.59 for observations and −0.53 for the models, with individual ensemble members having correlations as low as −0.26. Observed, ENSO-removed tropical land temperature and precipitation decrease by about 0.35 K and 0.25 mm day−1 after the Pinatubo eruption, while no significant decrease in either variable was observed after El Chichón. The AMIP models generally capture this behavior despite a tendency to overestimate the precipitation response to El Chichón. Scatter is substantial, both across models and across ensemble members of individual models. Natural variability thus may still play a prominent role despite the strong volcanic forcing.


2009 ◽  
Vol 22 (22) ◽  
pp. 6120-6141 ◽  
Author(s):  
David W. J. Thompson ◽  
John M. Wallace ◽  
Phil D. Jones ◽  
John J. Kennedy

Abstract Global-mean surface temperature is affected by both natural variability and anthropogenic forcing. This study is concerned with identifying and removing from global-mean temperatures the signatures of natural climate variability over the period January 1900–March 2009. A series of simple, physically based methodologies are developed and applied to isolate the climate impacts of three known sources of natural variability: the El Niño–Southern Oscillation (ENSO), variations in the advection of marine air masses over the high-latitude continents during winter, and aerosols injected into the stratosphere by explosive volcanic eruptions. After the effects of ENSO and high-latitude temperature advection are removed from the global-mean temperature record, the signatures of volcanic eruptions and changes in instrumentation become more clearly apparent. After the volcanic eruptions are subsequently filtered from the record, the residual time series reveals a nearly monotonic global warming pattern since ∼1950. The results also reveal coupling between the land and ocean areas on the interannual time scale that transcends the effects of ENSO and volcanic eruptions. Globally averaged land and ocean temperatures are most strongly correlated when ocean leads land by ∼2–3 months. These coupled fluctuations exhibit a complicated spatial signature with largest-amplitude sea surface temperature perturbations over the Atlantic Ocean.


1984 ◽  
Vol 23 (2) ◽  
pp. 129-141
Author(s):  
A. E. Strong

El velo de polvo de la erupción volcánica de El Chichón en abril de 1982 ha tenido un notable efecto sobre la capacidad del AVHRR del satélite NOAA-7 para registrar la temperatura de la superficie del mar (SST). Las pequeñas partículas de ácido sulfúrico de una micra o aún menos de tamaño en la estratosfera atenúan la radiación de la Tierra causando un desplazamiento (sesgo) negativo en los SSTs producidos operacionalmente por NOAA. Hemos utilizado este desplazamiento para observar mensualmente la evolución y dispersión de la nube de aerosol a medida que se esparcía rápidamente hacia el norte durante los meses de noviembre y diciembre de 1982 y hasta la primavera de 1983.


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