The Response of Permafrost and High‐Latitude Ecosystems Under Large‐Scale Stratospheric Aerosol Injection and Its Termination

AbstractIn this paper, we seek to ground discussions of the governance of stratospheric aerosol injection research in recent literature about the field including an updated understanding of the technology’s deployment logistics and scale, pattern of effects, and research pathways. Relying upon this literature, we evaluate several common reservations regarding the governance of pre-deployment research and testing including covert deployment, technological lock-in, weaponization, slippery slope, and the blurry line between research and deployment. We conclude that these reservations are no longer supported by literature. However, we do not argue that there is no reason for concern. Instead, we enumerate alternative bases for caution about research into stratospheric aerosol injection which are supported by an up-to-date understanding of the literature. We conclude that in order to establish the correct degree and type of governance for stratospheric aerosol injection research, the research community must focus its attention on these well-grounded reservations. However, while these reservations are supported and warrant further attention, we conclude that none currently justifies restrictive governance of early-stage stratospheric aerosol injection research.

Download Full-text

Small-scale characteristics of extremely high latitude aurora

Annales Geophysicae ◽

10.5194/angeo-27-3335-2009 ◽

2009 ◽

Vol 27 (9) ◽

pp. 3335-3347 ◽

Cited By ~ 8

Author(s):

J. A. Cumnock ◽

L. G. Blomberg ◽

A. Kullen ◽

T. Karlsson ◽

Keyword(s):

High Latitude ◽

Large Scale ◽

Small Scale ◽

Strong Correlations ◽

Polar Cap ◽

Plasma Flows ◽

Ionospheric Convection ◽

Local Closure ◽

Scale Characteristics

Abstract. We examine 14 cases of an interesting type of extremely high latitude aurora as identified in the precipitating particles measured by the DMSP F13 satellite. In particular we investigate structures within large-scale arcs for which the particle signatures are made up of a group of multiple distinct thin arcs. These cases are chosen without regard to IMF orientation and are part of a group of 87 events where DMSP F13 SSJ/4 measures emissions which occur near the noon-midnight meridian and are spatially separated from both the dawnside and duskside auroral ovals by wide regions with precipitating particles typical of the polar cap. For 73 of these events the high-latitude aurora consists of a continuous region of precipitating particles. We focus on the remaining 14 of these events where the particle signatures show multiple distinct thin arcs. These events occur during northward or weakly southward IMF conditions and follow a change in IMF By. Correlations are seen between the field-aligned currents and plasma flows associated with the arcs, implying local closure of the FACs. Strong correlations are seen only in the sunlit hemisphere. The convection associated with the multiple thin arcs is localized and has little influence on the large-scale convection. This also implies that the sunward flow along the arcs is unrelated to the overall ionospheric convection.

Download Full-text

An Interpretation of the Distribution of Metre Wavelength Radio Emission

Australian Journal of Physics ◽

10.1071/ph680167 ◽

1968 ◽

Vol 21 (2) ◽

pp. 167 ◽

Cited By ~ 35

Author(s):

KW Yates

Keyword(s):

High Latitude ◽

Large Scale ◽

Galactic Halo ◽

Galactic Plane ◽

Absolute Calibration ◽

Fundamental Difficulty ◽

The Galaxy ◽

Calibration Accuracy ◽

Limit Estimate ◽

Spiral Arm

A recent 85 MHz survey of the southern sky had an absolute calibration accuracy and resolution comparable with a number of surveys made for the northern skies. By combining the results of these surveys in both hemispheres a complete sky map has been produced, and in this paper an analysis is made of the distribution of the medium and high latitude emission. A fundamental difficulty encountered is the identification and isolation of the spurs of emission projecting from the galactic plane. Two hypotheses are proposed. The first attributes the spurs to a large-scale feature associated with the galactic core and the remaining emission to a galactic halo. The second postulates the origin of the spurs within the local spiral arm, which is itself considered to contribute significantly to the high latitude background. An upper-limit estimate of the emissivity of the local arm is made from currently available independent data. Using this result a model local arm is proposed, which, together with an isotropic component from beyond the Galaxy and a small additional galactic component, explains the observed distribution.

Download Full-text

Climate engineering and the ocean: effects on biogeochemistry and primary production

10.5194/bg-2017-235 ◽

2017 ◽

Cited By ~ 1

Author(s):

Siv K. Lauvset ◽

Jerry Tjiputra ◽

Helene Muri

Keyword(s):

Primary Production ◽

Radiative Forcing ◽

Large Scale ◽

Stratospheric Aerosol ◽

Climate Impacts ◽

Environmental Drivers ◽

Earth System ◽

Climate Engineering ◽

Mean Sea Surface ◽

Radiation Management

Abstract. Here we use an Earth System Model with interactive biogeochemistry to project future ocean biogeochemistry impacts from large-scale deployment of three different radiation management (RM) climate engineering (also known as geoengineering) methods: stratospheric aerosol injection (SAI), marine sky brightening (MSB), and cirrus cloud thinning (CCT). We apply RM such that the change in radiative forcing in the RCP8.5 emission scenario is reduced to the change in radiative forcing in the RCP4.5 scenario. The resulting global mean sea surface temperatures in the RM experiments are comparable to those in RCP4.5, but there are regional differences. The forcing from MSB, for example, is applied over the oceans, so the cooling of the ocean is in some regions stronger for this method of RM than for the others. Changes in ocean primary production are much more variable, but SAI and MSB give a global decrease comparable to RCP4.5 (~ 6 % in 2100 relative to 1971–2000), while CCT give a much smaller global decrease of ~ 3 %. The spatially inhomogeneous changes in ocean primary production are partly linked to how the different RM methods affect the drivers of primary production (incoming radiation, temperature, availability of nutrients, and phytoplankton) in the model. The results of this work underscores the complexity of climate impacts on primary production, and highlights that changes are driven by an integrated effect of multiple environmental drivers, which all change in different ways. These results stress the uncertain changes to ocean productivity in the future and advocates caution at any deliberate attempt for large-scale perturbation of the Earth system.

Download Full-text

Expansion and diversification of high-latitude radiolarian assemblages in the late Eocene linked to a cooling event in the Southwest Pacific

Climate of the Past Discussions ◽

10.5194/cpd-11-2977-2015 ◽

2015 ◽

Vol 11 (4) ◽

pp. 2977-3018 ◽

Cited By ~ 1

Author(s):

K. M. Pascher ◽

C. J. Hollis ◽

S. M. Bohaty ◽

G. Cortese ◽

R. M. McKay

Keyword(s):

Oxygen Isotope ◽

High Latitude ◽

Large Scale ◽

Middle Eocene ◽

Late Eocene ◽

Climate History ◽

Southwest Pacific ◽

Early Oligocene ◽

Radiolarian Assemblages

Abstract. The Eocene was characterised by "greenhouse" climate conditions that were gradually terminated by a long-term cooling trend through the middle and late Eocene. This long-term trend was determined by several large-scale climate perturbations that culminated in a shift to "ice-house" climates at the Eocene–Oligocene Transition. Geochemical and micropaleontological proxies suggest that tropical-to-subtropical sea-surface temperatures persisted into the late Eocene in the high-latitude Southwest Pacific Ocean. Here, we present radiolarian microfossil assemblage and foraminiferal oxygen and carbon stable isotope data from Deep Sea Drilling Project (DSDP) Sites 277, 280, 281 and 283 from the middle Eocene to early Oligocene (~ 40–33 Ma) to identify oceanographic changes in the Southwest Pacific across this major transition in Earth's climate history. The Middle Eocene Climatic Optimum at ~ 40 Ma is characterised by a negative shift in foraminiferal oxygen isotope values and a radiolarian assemblage consisting of about 5 % of low latitude taxa Amphicraspedum prolixum group and Amphymenium murrayanum. In the early late Eocene at ~ 37 Ma, a positive oxygen isotope shift can be correlated to the Priabonian Oxygen Isotope Maximum (PrOM) event – a short-lived cooling event recognized throughout the Southern Ocean. Radiolarian abundance, diversity, and preservation increase during the middle of this event at Site 277 at the same time as diatoms. The PrOM and latest Eocene radiolarian assemblages are characterised by abundant high-latitude taxa. These high-latitude taxa also increase in abundance during the late Eocene and early Oligocene at DSDP Sites 280, 281 and 283 and are associated with very high diatom abundance. We therefore infer a~northward expansion of high-latitude radiolarian taxa onto the Campbell Plateau towards the end of the late Eocene. In the early Oligocene (~ 33 Ma) there is an overall decrease in radiolarian abundance and diversity at Site 277, and diatoms are absent. These data indicate that, once the Tasman Gateway was fully open in the early Oligocene, a frontal system similar to the present day was established, with nutrient-depleted subantarctic waters bathing the area around DSDP Site 277, resulting in a more oligotrophic siliceous plankton assemblage.

Download Full-text

Model simulation of the large-scale high-latitude F-layer modification by powerful HF waves with different modulation

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/j.jastp.2008.11.007 ◽

2009 ◽

Vol 71 (5) ◽

pp. 559-568 ◽

Cited By ~ 6

Author(s):

G.I. Mingaleva ◽

V.S. Mingalev ◽

I.V. Mingalev

Keyword(s):

High Latitude ◽

Large Scale ◽

Model Simulation

Download Full-text

The prevalence of meteoric-sulphuric particles within the stratospheric aerosol layer

10.5194/egusphere-egu21-15390 ◽

2021 ◽

Author(s):

Graham Mann ◽

James Brooke ◽

Kamalika Sengupta ◽

Lauren Marshall ◽

Sandip Dhomse ◽

...

Keyword(s):

High Latitude ◽

Climate Model ◽

Polar Vortex ◽

Stratospheric Aerosol ◽

Light Extinction ◽

The Arctic ◽

Aerosol Layer ◽

Aerosol Composition ◽

Particle Layer

The widespread presence of meteoric smoke particles (MSPs) within a distinct class of stratospheric aerosol particles has become clear from in-situ measurements in the Arctic, Antarctic and at mid-latitudes. &#160; We apply an adapted version of the interactive stratosphere aerosol configuration of the composition-climate model UM-UKCA, to predict the global distribution of meteoric-sulphuric particles nucleated heterogeneously on MSP cores. We compare the UM-UKCA results to new MSP-sulphuric simulations with the European stratosphere-troposphere chemistry-aerosol modelling system IFS-CB05-BASCOE-GLOMAP. The simulations show a strong seasonal cycle in meteoric-sulphuric particle abundance results from the winter-time source of MSPs transported down into the stratosphere in the polar vortex. Coagulation during downward transport sees high latitude MSP concentrations reduce from ~500 per cm3 at 40km to ~20 per cm3 at 25km, the uppermost extent of the stratospheric aerosol particle layer (the Junge layer). &#160; Once within the Junge layer's supersaturated environment, meteoric-sulphuric particles form readily on the MSP cores, growing to 50-70nm dry-diameter (Dp) at 20-25km. Further inter-particle coagulation between these non-volatile particles reduces their number to 1-5 per cc at 15-20km, particle sizes there larger, at Dp ~100nm. The model predicts meteoric-sulphurics in high-latitude winter comprise >90% of Dp>10nm particles above 25km, reducing to ~40% at 20km, and ~10% at 15km. &#160; These non-volatile particle fractions are slightly less than measured from high-altitude aircraft in the lowermost Arctic stratosphere (Curtius et al., 2005; Weigel et al., 2014), and consistent with mid-latitude aircraft measurements of lower stratospheric aerosol composition (Murphy et al., 1998), total particle concentrations &#160;also matching in-situ balloon measurements from Wyoming (Campbell and Deshler, 2014). &#160; The MSP-sulphuric interactions also improve agreement with SAGE-II observed stratospheric aerosol extinction in the quiescent 1998-2002 period.&#160; &#160; Simulations with a factor-8-elevated MSP input form more Dp>10nm meteoric-sulphurics, but the increased number sees fewer growing to Dp ~100nm, the increased MSPs reducing the stratospheric aerosol layer&#8217;s light extinction.

Download Full-text

Global streamflow and flood response to stratospheric aerosol geoengineering

10.5194/acp-2018-338 ◽

2018 ◽

Cited By ~ 1

Author(s):

Liren Wei ◽

Duoying Ji ◽

Chiyuan Miao ◽

John C. Moore

Keyword(s):

Return Period ◽

Flood Risk ◽

Large Scale ◽

Hydrological Cycle ◽

Stratospheric Aerosol ◽

Model Intercomparison ◽

Geographic Pattern ◽

Solar Geoengineering ◽

Intercomparison Project ◽

Future Warming

Abstract. Flood risk is projected to increase under projections of future warming climates due to an enhanced hydrological cycle. Solar geoengineering is known to reduce precipitation and slowdown the hydrological cycle, and may be therefore be expected to offset increased flood risk. We examine this hypothesis using streamflow and river discharge responses to the representative concentration pathway RCP4.5 and Geoengineering Model Intercomparison Project (GeoMIP) G4 experiments. We also calculate changes in 30, 50, 100-year flood return periods relative to the historical (1960–1999) period under the RCP4.5 and G4 scenarios. Similar spatial patterns are produced for each return period, although those under G4 are closer to historical values than under RCP4.5. Under G4 generally lower streamflows are produced on the western sides of Eurasia and North America, with higher flows on their eastern sides. In the southern hemisphere northern parts of the land masses have lower streamflow under G4, and southern parts increases relative to RCP4.5. So in general solar geoengineering does appear to reduce flood risk in most regions, but the relative effects are largely determined by this large scale geographic pattern. Both streamflow and return period show increased drying of the Amazon under both RCP4.5 and G4 scenarios, with more drying under G4.

Download Full-text