Policy Implications of Greenhouse Warming Mitigation, Adaptation, and the Science Base (1992) / Chapter Skim
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Q Geoengineering Options
Q Geoengineering Options
Pages 817-835
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From page 817... ...
If a single rifle can fire 5 shots per hour (naval rifles can fire faster than this, but cooling intervals between shots can lengthen the barrel life) and the rifle operates 250 working days per year, then a rifle can fire 5 shots/ hour x 24 hours/day x 250 days/yr = 3 x 104 shots/yr per rifle.
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From page 818... ...
The total cost of rifle barrels is thus 3 x 105 barrels x 106 $/barrel = $3 x 10i ~ for barrels. If the rifles are organized into 10-barrel stations, on land or at sea, and a billion dollars is allocated for the capital cost of each station, one might expect to buy 40 10-barrel stations to keep 350 barrels operating at a time, thus giving a cost for stations of 40 stations x 109 $/station= $4 x 10~°.
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From page 819... ...
If the balloon is 2/3-mm-thick (assumed for convenience) , its mass from the previous computation is 1.5 x 105 kg and the mass of dust lifted, if a 50 percent efficiency factor is used to account for instruments, dust dispenser, container, and so on (this is conservative)
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From page 820... ...
Hydrogen can currently be purchased as liquid hydrogen in 1500-gallon lots (equivalent to 169,000 standard cubic feet)
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From page 821... ...
Again by using the Archimedes principle, mdisplaced mgas + mballoon + mpayload Vpo VPi + mballoon + mpayload Using the perfect gas law PiVi = miRTi Pi = RpiTi p0VO = mORTO p0 = RpoTo where m = mass, V = volume, p0 = outside pressure, Pi = inside pressure, p0 = dens~ty ot a~r outside, and Pi = density of gas inside. At floating equilib rium, p0 = Pi, because the balloon is limp.
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From page 822... ...
Thus the costs of a hot air balloon system can be expected to be at least 4 to 10 times higher than the cost of a hydrogen balloon system. These costs
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From page 823... ...
While the skin temperature of a hot air balloon is well below the core gas temperature, the management of temperature to guarantee skin strength with so large a differential between average and skin temperature seems rather difficult, although the skin might be insulated as some weight penalty. The results are sensitive to the factors.
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From page 824... ...
. ,,- ~ CHANGING CLOUD ABUNDANCE A study was undertaken to consider the various factors that would be required to increase the albedo effect of global cloud cover sufficiently to balance the temperature increase that is projected to occur with a doubling of CO2.
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From page 825... ...
TABLE Q.1 Assumed Properties of Average Global Clouds Cloud Type High Middle Low Cloud Abundances Fraction of shortwave cloud cover Fraction of longwave cloud cover Cloud Optical Properties Solar albedo of cloud cover Solar absorptivity of cloud cover Infrared absorptivity of cloud cover 0.181 0.079 0.302 0.181 0.079 0.302 0.21 0.48 0.69 0.005 0.02 0.035 0.50 1.00 1.00
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From page 826... ...
, has also illustrated cloud height effect. These calculations show heating from high-level clouds and cooling from middle- and lower-level TABLE Q.2 Calculated Surface Temperature Sensitivity to Changes in Cloud Properties Cloud Type High Middle Low Sensitivity (°C)
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From page 827... ...
See, for example, the cloud experiments suggested below. With all the above assumptions in mind, it is proposed both that CCN emissions should be done over the oceans at an altitude that will produce an increase in the stratocumulus cloud albedo only, and that the clouds will remain at the same latitudes over the ocean where the surface albedo is relatively constant and low.
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From page 828... ...
ness in the arctic region to promote ice melting and improve growing conditions in Siberia. Before the more recent satellite measurements, most of what was known about cloud processes and how they contribute to the global radiative balance came from climate modeling, and in climate models, most of the details of the cloud processes were not included.
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From page 829... ...
This assumes that the perturbed atmosphere would remain sufficiently close to saturation in the vicinity of the CCN that additional cloud cover would be formed every time the number of CCN increased. Now an extrapolation will be made to the entire globe, while keeping in mind Albrecht's assumption that cloudiness in a typical ocean region is limited by the small number of CCN.
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From page 830... ...
They are vectored on paths to cloud-covered areas by a control center that uses weather satellite data to plan the campaign. In addition to choosing areas that contain clouds, it is important to distribute the ships and their burning pattern so as not to create major regional changes, or the kind of change with a time or space pattern likely to force unwanted wave patterns.
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From page 831... ...
Consequently, there should already be some cloud-enhancing effects evident in the northern hemisphere if Twomey and Wojciechowski's hypothesis, as implemented by Albrecht, is correct. An examination of available CCN data shows that the mean CCN concentration at oceanic locations in the northern Atlantic is about 5 times higher than at remote locations in the southern Pacific (see Schwartz (1988)
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From page 832... ...
presents some crude calculations suggesting that SO2/ CCN-derived forcing could be large enough to have offset any temperature increase due to CO2 in the northern hemisphere. Schneider (1972)
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From page 833... ...
Necessary Cloud Condensation Nuclei Experiments If global-scale CCN emissions were to be considered in a serious way a number of fundamental studies would need to be performed. Among these would be the following: · Exploratory studies of the effectiveness of CCN for enhancing stratocumulus cloud cover, with a full statistical analysis of covariates, and so on.
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From page 834... ...
1978. Thermal Effects of Cloud Parameter Variations in the ManabeWetherald Radiative-Convective Atmospheric Model.
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From page 835... ...
1988. Are global cloud albedo and climate controlled by marine phytoplankton?
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