RE: [geo] The Shortwave Radiative Flux Response to an Injection of Sea Salt Aerosols in the Gulf of Mexico

[david.sevier]

Some questions:

 

1.  I am assuming that we are talking about 10.8 Tg yr of sea water and not 
10.8 Tg of salt. Is this correct?
2.  To what height is the injection being modelled at?
3.  Any idea of the predicted energy calculation for delivering and 
spraying this much material to this height?

 

 

David Sevier

 

Carbon Cycle Limited

248 Sutton Common Road

Sutton, Surrey SM3 9PW

England

 

Tel 44 (0) 208 288 0128

www.carbon-cycle.co.uk

 

 

 

 

 

From: geoengineering@googlegroups.com  On 
Behalf Of Andrew Lockley
Sent: 09 November 2022 21:04
To: geoengineering 
Subject: [geo] The Shortwave Radiative Flux Response to an Injection of Sea 
Salt Aerosols in the Gulf of Mexico

 

 

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022JD037067

 

Authors

P. B. Goddard,B. Kravitz,D. G. MacMartin,H. Wang

 

November 4th, 2022

 

Abstract

Marine cloud brightening (MCB) has been proposed as a potential means of 
geoengineering the climate, temporarily providing cooling to offset some of the 
effects of climate change. Marine sky brightening (MSB), involving direct 
scattering of sunlight from sea salt injection into the marine boundary layer, 
has been proposed as an additional geoengineering method that could work in 
areas that are not regularly cloudy. Here we use a regional atmospheric model 
to simulate MCB and MSB over the Gulf of Mexico and nearby land, a highly 
populated and economically important region that is not characterized by 
persistent marine stratocumulus cloud cover. Injection of sea salt in the 
Aitken mode from a region in the central Gulf of Mexico equivalent to 10.8 Tg 
yr-1 produces an upwards 8.4 W m-2 radiative flux change across the region at 
the top of the atmosphere, largely due to cloud property changes. 
Comparatively, a similar mass injection in the accumulation mode produces a 3.1 
W m-2 radiative flux change driven primarily by direct scattering. Injection of 
even larger particles produces a much smaller radiative flux change. Shortwave 
flux changes due to clouds are largely driven by an increase in cloud droplet 
number concentration and an increase in cloud liquid water path (each 
contributing about 45% to the flux change), with a much lower contribution from 
cloud fraction changes (10%).

 

Source: AGU

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[geo] Towards photophoretically levitating macroscopic sensors in the stratosphere

[Andrew Lockley]

Towards photophoretically levitating macroscopic sensors in the
stratosphere

Benjamin C. Schafer1,*, Jong-hyoung Kim1, Joost J. Vlassak1, David W. Keith1

--
Abstract

Photophoretic forces could levitate thin 10 centimeter-scale structures in
Earth’s stratosphere indefinitely. We develop models of the thermal
transpiration lofting force on a bilayer sandwich structure under
stratospheric conditions driven by radiative fluxes in the thermal-infrared
and solar-band. Similar structures have been levitated in the laboratory.
Lofting is maximized when the layers are separated by an air gap equal to
the mean free path (MFP), when about half of the layers’ surface area
consists of holes with radii < MFP, and when the top layer is
solar­transmissive
and infrared-emissive while the bottom layer is solar-absorptive and
infrared­transmissive. We describe a preliminary design of a 10 cm diameter
device that combines a levitating structure made of two membranes 2 µm
apart with the support structure required for stiffness and orientation
control. We limit the design to components that could be fabricated with
available methods. Structural analysis suggests that the device would have
sufficient strength to withstand forces that might be encountered in
transport, deployment, and flight. Our models predict a payload capacity of
about 300 mg at 25 km altitude and our analysis suggests it could support
bidirectional radio communication at over 10 Mb/s and could have limited
navigational abilities. Such devices could be useful for atmospheric
science or telecommunications, and similar devices might be useful on Mars.
Structures a few times larger might have payloads of a few grams.


[PDF] Towards photophoretically levitating macroscopic sensors in the
stratosphere

BC Schafer, J Kim, JJ Vlassak, DW Keith - arXiv preprint arXiv:2209.08093,
2022
Photophoretic forces could levitate thin 10 centimeter-scale structures in
Earth $'$ s
stratosphere indefinitely. We develop models of the thermal transpiration
lofting force
on a bilayer sandwich structure under stratospheric conditions driven by
radiative …
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[geo] Atmospheric Removal of Methane by enhancing the natural hydroxyl radical sink

[Andrew Lockley]

https://onlinelibrary.wiley.com/doi/abs/10.1002/ghg.2191

Atmospheric Removal of Methane by enhancing the natural hydroxyl radical
sink
Yuyin Wang,Tingzhen Ming,Wei Li,Qingchun Yuan,Renaud de Richter,Philip
Davies,Sylvain Caillol
First published: 07 November 2022
https://doi.org/10.1002/ghg.2191
This article has been accepted for publication and undergone full peer
review but has not been through the copyediting, typesetting, pagination
and proofreading process, which may lead to differences between this
version and the Version of Record. Please cite this article as
https://doi.org/10.1002/ghg.2191
About


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Abstract
According to the latest report from the Intergovernmental Panel on Climate
Change (IPCC), currently, global warming due to methane (CH4) alone is
about 0.5°C while due to carbon dioxide (CO2) alone is about 0.75°C. As CH4
emissions will continue growing, in order to limit warming to 1.5˚C, some
of the most effective strategies are rapidly reducing CH4 emissions and
developing large scale CH4 removal methods. The aim of this review article
is to summarise and propose possible methods for atmospheric CH4 removal,
based on the hydroxyl radical (°OH), which is the principal natural sink of
many gases in the atmosphere and on many water surfaces. Inspired by
mechanisms of °OH generation in the atmosphere and observed or predicted
enhancement of °OH by climate change and human activities, we proposed
several methods to enhance the °OH sink by some physical means using water
vapour and artificial UV radiation.

Synopsis: Atmospheric methane concentrations are high and rising. This
review article assesses the status and proposes new methods for atmospheric
methane removal.

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