Witnessing the impact of the 1783–1784 Laki eruption in the Southern Hemisphere

2009 ◽  
Vol 99 (3-4) ◽  
pp. 535-546 ◽  
Author(s):  
Ricardo M. Trigo ◽  
J. M. Vaquero ◽  
R. B. Stothers
Keyword(s):  
Southern Hemisphere ◽  
The Impact

scholarly journals Spatial and seasonal effects on the delayed ionospheric response to solar EUV changes

2019 ◽  
Author(s):  
Erik Schmölter ◽  
Jens Berdermann ◽  
Norbert Jakowski ◽  
Christoph Jacobi
Keyword(s):  
Southern Hemisphere ◽  
Geomagnetic Activity ◽  
Correlation Coefficients ◽  
Seasonal Effects ◽  
Constant Delay ◽  
Average Delay ◽  
Ionospheric Response ◽  
The Difference ◽  
Longitudinal Variability ◽  
The Impact

Abstract. This study correlates different ionospheric parameters with the integrated solar EUV radiation for an analysis of the delayed ionospheric response in order to confirm previous studies on the delay and to further specify variations of the delay. Several time series for correlation coefficients and delays are presented to characterize the trend of the delay from 2011 to 2013. The impact of the diurnal variations of ionospheric parameters in the analysis on hourly resolution for fixed locations are discussed and specified with calculations in different time scales and with comparison to solar and geomagnetic activity. An average delay for TEC of ≈ 18.7 hours and for foF2 of ≈ 18.6 hours is calculated at four European stations. Through comparison with the Australian region the difference between northern and southern hemisphere is analyzed and a seasonal variation of the delay between northern and southern hemisphere is calculated for TEC with ≈ 5 ± 0.7 hours and foF2 with ≈ 8 ± 0.8 hours. The latitudinal and longitudinal variability of the delay is analyzed for the European region and a decrease of the delay from ≈ 21.5 hours at 30° N to ≈ 19.0 hours at 70° N has been found. For winter months a roughly constant delay of ≈ 19.5 hours is calculated. In this study a North-South trend of the ionospheric delay during summer month has been observed with ≈ 0.06 hours per degree in latitude. The results based on solar and ionospheric data in hourly resolution and the analysis of the delayed ionospheric response to solar EUV show the seasonal and latitudinal variations. Results also indicate the dependence on the geomagnetic activity as well as on the 11-year solar cycle.

scholarly journals The impact of the Southern Annular Mode on future changes in Southern Hemisphere rainfall

2016 ◽  
Vol 43 (13) ◽  
pp. 7160-7167 ◽  
Author(s):  
Eun-Pa Lim ◽  
Harry H. Hendon ◽  
Julie M. Arblaster ◽  
Francois Delage ◽  
Hanh Nguyen ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Southern Annular Mode ◽  
Annular Mode ◽  
The Impact

Uncharted waters: LNG as a marine fuel in Australasia

2017 ◽  
Vol 57 (2) ◽  
pp. 434
Author(s):  
Rob Duncanson ◽  
Walter P. Purio
Keyword(s):  
Public Health ◽  
Southern Hemisphere ◽  
Emerging Market ◽  
Maritime Industry ◽  
Marine Fuel ◽  
Global Context ◽  
Energy Independence ◽  
Lng Fuel ◽  
The Impact

This paper explores the emerging market for liquefied natural gas (LNG) as a marine fuel, with a particular focus on the market in Australasia. While LNG as a marine fuel is a growing market in the northern hemisphere, slower rates of adoption of LNG fuel technologies in maritime industry are evident in the southern hemisphere. This paper aims to ground the Australasian LNG marine fuel market in a global context and to explore opportunities for Australia to lead the region in developing and adopting LNG as a marine fuel. This paper looks at the key drivers behind championing LNG as a marine fuel, focusing on four main areas of impact; economy, environment, public health and innovation. This paper uses Australia as a case study for the adoption of LNG as a marine fuel in the southern hemisphere. It considers the opportunities presented by LNG as a marine fuel to assist Australia in: achieving energy independence; reducing the impact of air pollution from ships on the environment and public health; and positioning Australia as an innovative leader in LNG as a marine fuel.

Tropical Connections to Climatic Change in the Extratropical Southern Hemisphere: The Role of Atlantic SST Trends

2014 ◽  
Vol 27 (13) ◽  
pp. 4923-4936 ◽  
Author(s):  
Graham R. Simpkins ◽  
Shayne McGregor ◽  
Andréa S. Taschetto ◽  
Laura M. Ciasto ◽  
Matthew H. England
Keyword(s):  
Climatic Change ◽  
Atmospheric Circulation ◽  
Southern Hemisphere ◽  
Geopotential Height ◽  
General Circulation ◽  
Rossby Waves ◽  
Circulation Model ◽  
Hadley Cell ◽  
Austral Spring ◽  
The Impact

The austral spring relationships between sea surface temperature (SST) trends and the Southern Hemisphere (SH) extratropical atmospheric circulation are investigated using an atmospheric general circulation model (AGCM). A suite of simulations are analyzed wherein the AGCM is forced by underlying SST conditions in which recent trends are constrained to individual ocean basins (Pacific, Indian, and Atlantic), allowing the impact of each region to be assessed in isolation. When forced with observed global SST, the model broadly replicates the spatial pattern of extratropical SH geopotential height trends seen in reanalyses. However, when forcing by each ocean basin separately, similar structures arise only when Atlantic SST trends are included. It is further shown that teleconnections from the Atlantic are associated with perturbations to the zonal Walker circulation and the corresponding intensification of the local Hadley cell, the impact of which results in the development of atmospheric Rossby waves. Thus, increased Rossby waves, forced by positive Atlantic SST trends, may have played a role in driving geopotential height trends in the SH extratropics. Furthermore, these atmospheric circulation changes promote warming throughout the Antarctic Peninsula and much of West Antarctica, with a pattern that closely matches recent observational records. This suggests that Atlantic SST trends, via a teleconnection to the SH extratropics, may have contributed to springtime climatic change in the SH extratropics over the past three decades.

scholarly journals Long-range isentropic transport of stratospheric aerosols over Southern Hemisphere following the Calbuco eruption in April 2015

2017 ◽  
Author(s):  
Nelson Bègue ◽  
Damien Vignelles ◽  
Gwenaël Berthet ◽  
Thierry Portafaix ◽  
Guillaume Payen ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Transient Behavior ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Reunion Island ◽  
Volcanic Aerosol ◽  
Réunion Island ◽  
One Year ◽  
The Impact ◽  
Aerosol Plume

Abstract. After 43 years of inactivity, the Calbuco volcano which is located in the southern part of Chile erupted on 22 April 2015. The space-time evolutions (distribution and transport) of its aerosol plume are investigated by combining satellite (CALIOP, IASI, OMPS), in situ aerosol counting (LOAC OPC) and lidar observations, and the MIMOSA advection model. The Calbuco aerosol plume reached the Indian Ocean 1 week after the eruption. Over the Reunion Island site (21° S; 55.5° E), the aerosol signal was unambiguously enhanced in comparison with "background" conditions with a volcanic aerosol layer extending from 18 km to 21 km during the May–July period. All the data reveal an increase by a factor of ~ 2 in the SAOD (Stratospheric Aerosol Optical Depth) with respect to values observed before the eruption. The aerosol e-folding time is approximately 90 days. Microphysical measurements obtained before, during and after the eruption reflecting the impact of the Calbuco eruption on the lower stratospheric aerosol content have been analyzed over Reunion site. During the passage of the plume, the volcanic aerosol was characterized by an effective radius of 0.16 ± 0.02 µm with an unimodal lognormal size distribution and the aerosol number concentration appears 20 times higher than before and one year after the eruption. A tendency toward "background" conditions has been observed about one year after the eruption, by April 2016. The volcanic aerosol plume is advected eastward in the Southern Hemisphere and its latitudinal extent is clearly bounded by the subtropical barrier and the polar vortex. The transient behavior of the aerosol layers observed above Reunion Island between May and July 2015 reflects an inhomogeneous geographical distribution of the plume which is controlled by the latitudinal motion of these dynamical barriers.

scholarly journals Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP

2013 ◽  
Vol 9 (2) ◽  
pp. 887-901 ◽  
Author(s):  
P. Mathiot ◽  
H. Goosse ◽  
X. Crosta ◽  
B. Stenni ◽  
M. Braida ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Southern Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Atmospheric Circulation ◽  
Southern Hemisphere ◽  
Sea Surface ◽  
Freshwater Flux ◽  
West Antarctic ◽  
The Impact

Abstract. From 10 to 8 ka BP (thousand years before present), paleoclimate records show an atmospheric and oceanic cooling in the high latitudes of the Southern Hemisphere. During this interval, temperatures estimated from proxy data decrease by 0.8 °C over Antarctica and 1.2 °C over the Southern Ocean. In order to study the causes of this cooling, simulations covering the early Holocene have been performed with the climate model of intermediate complexity LOVECLIM constrained to follow the signal recorded in climate proxies using a data assimilation method based on a particle filtering approach. The selected proxies represent oceanic and atmospheric surface temperature in the Southern Hemisphere derived from terrestrial, marine and glaciological records. Two mechanisms previously suggested to explain the 10–8 ka BP cooling pattern are investigated using the data assimilation approach in our model. The first hypothesis is a change in atmospheric circulation, and the second one is a cooling of the sea surface temperature in the Southern Ocean, driven in our experimental setup by the impact of an increased West Antarctic melting rate on ocean circulation. For the atmosphere hypothesis, the climate state obtained by data assimilation produces a modification of the meridional atmospheric circulation leading to a 0.5 °C Antarctic cooling from 10 to 8 ka BP compared to the simulation without data assimilation, without congruent cooling of the atmospheric and sea surface temperature in the Southern Ocean. For the ocean hypothesis, the increased West Antarctic freshwater flux constrainted by data assimilation (+100 mSv from 10 to 8 ka BP) leads to an oceanic cooling of 0.7 °C and a strengthening of Southern Hemisphere westerlies (+6%). Thus, according to our experiments, the observed cooling in Antarctic and the Southern Ocean proxy records can only be reconciled with the reconstructions by the combination of a modified atmospheric circulation and an enhanced freshwater flux.

scholarly journals Climate impact of volcanic eruptions: the sensitivity to eruption season and latitude in MPI-ESM ensemble experiments

2021 ◽  
Author(s):  
Zhihong Zhuo ◽  
Ingo Kirchner ◽  
Stephan Pfahl ◽  
Ulrich Cubasch
Keyword(s):  
Southern Hemisphere ◽  
South Asian ◽  
Volcanic Eruptions ◽  
Climate Impacts ◽  
South Asian Summer Monsoon ◽  
The South ◽  
Radiative Effects ◽  
Near Surface ◽  
Volcanic Aerosols ◽  
The Impact

Abstract. Explosive volcanic eruptions influence near-surface temperature and precipitation especially in the monsoon regions, but the impact varies with different eruption seasons and latitudes. To study this variability, two groups of ensemble simulations are performed with volcanic eruptions in June and December at 0° representing an equatorial eruption (EQ) and at 30° N and 30° S representing northern and southern hemisphere eruptions (NH and SH). Results show significant cooling especially in areas with enhanced volcanic aerosol content. Stronger cooling emerges in the northern (southern) hemisphere after the NH (SH) eruption compared to the EQ eruption. Stronger precipitation variations occur in the tropics than in the high latitudes. Summer and winter eruptions lead to similar climate impacts. The NH and the SH eruptions have reversed climate impacts, especially in the South Asian monsoon regions. After the NH (SH) eruption, direct radiative effects of volcanic aerosols induce changes in the interhemispheric and land-sea thermal contrasts, which move the intertropical convergence zone southward (northward) and weaken (strengthen) the South Asian summer monsoon. This reduces (increases) the moisture transport from the ocean to India, and reduces (enhances) cloud formation. The subsequent radiative feedbacks due to regional cloud cover lead to warming (cooling) in India. This emphasis the sensitivity of regional climate impacts of volcanic eruptions to eruption latitude, which relates to the dynamical response of the climate system to radiative effects of volcanic aerosols and the subsequent regional physical feedbacks.

Examining the impact of multiple climate forcings on simulated Southern Hemisphere climate variability

2020 ◽  
Vol 54 (11-12) ◽  
pp. 4775-4792
Author(s):  
Asmerom F. Beraki ◽  
Yushi Morioka ◽  
Francois A. Engelbrecht ◽  
Masami Nonaka ◽  
Marcus Thatcher ◽  
...  
Keyword(s):  
Climate Variability ◽  
Southern Hemisphere ◽  
Climate Forcings ◽  
The Impact

scholarly journals The Impact of Stratospheric Ozone Recovery on Tropopause Height Trends

2009 ◽  
Vol 22 (2) ◽  
pp. 429-445 ◽  
Author(s):  
Seok-Woo Son ◽  
Lorenzo M. Polvani ◽  
Darryn W. Waugh ◽  
Thomas Birner ◽  
Hideharu Akiyoshi ◽  
...  
Keyword(s):  
Climate Change ◽  
Southern Hemisphere ◽  
Climate Models ◽  
Stratospheric Ozone ◽  
Reliable Estimate ◽  
Intergovernmental Panel ◽  
The Future ◽  
Realistic Representation ◽  
High Vertical Resolution ◽  
The Impact

Abstract The evolution of the tropopause in the past, present, and future climate is examined by analyzing a set of long-term integrations with stratosphere-resolving chemistry climate models (CCMs). These CCMs have high vertical resolution near the tropopause, a model top located in the mesosphere or above, and, most important, fully interactive stratospheric chemistry. Using such CCM integrations, it is found that the tropopause pressure (height) will continue to decrease (increase) in the future, but with a trend weaker than that in the recent past. The reduction in the future tropopause trend is shown to be directly associated with stratospheric ozone recovery. A significant ozone recovery occurs in the Southern Hemisphere lower stratosphere of the CCMs, and this leads to a relative warming there that reduces the tropopause trend in the twenty-first century. The future tropopause trends predicted by the CCMs are considerably smaller than those predicted by the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) models, especially in the southern high latitudes. This difference persists even when the CCMs are compared with the subset of the AR4 model integrations for which stratospheric ozone recovery was prescribed. These results suggest that a realistic representation of the stratospheric processes might be important for a reliable estimate of tropopause trends. The implications of these finding for the Southern Hemisphere climate change are also discussed.

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