scholarly journals Toward practical stratospheric aerosol albedo modification: Solar-powered lofting

2021 ◽  
Vol 7 (20) ◽  
pp. eabe3416
Author(s):  
Ru-Shan Gao ◽  
Karen H. Rosenlof ◽  
Bernd Kärcher ◽  
Simone Tilmes ◽  
Owen B. Toon ◽  
...  

Many climate intervention (CI) methods have been proposed to offset greenhouse gas–induced global warming, but the practicalities regarding implementation have not received sufficient attention. Stratospheric aerosol injection (SAI) involves introducing large amounts of CI material well within the stratosphere to enhance the aerosol loading, thereby increasing reflection of solar radiation. We explore a delivery method termed solar-powered lofting (SPL) that uses solar energy to loft CI material injected at lower altitudes accessible by conventional aircraft. Particles that absorb solar radiation are dispersed with the CI material and heat the surrounding air. The heated air rises, carrying the CI material to the stratosphere. Global model simulations show that black carbon aerosol (10 microgram per cubic meter) is sufficient to quickly loft CI material well into the stratosphere. SPL could make SAI viable at present, is also more energy efficient, and disperses CI material faster than direct stratospheric injection.


2021 ◽  
Vol 164 (3-4) ◽  
Author(s):  
Wake Smith ◽  
Claire Henly

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.



2017 ◽  
Author(s):  
Laura Revell ◽  
Andrea Stenke ◽  
Beiping Luo ◽  
Stefanie Kremser ◽  
Eugene Rozanov ◽  
...  

Abstract. To simulate the impacts of volcanic eruptions on the stratosphere, chemistry-climate models that do not include an online aerosol module require temporally and spatially resolved aerosol size parameters for heterogeneous chemistry and aerosol radiative properties as a function of wavelength. For phase 1 of the Chemistry-Climate Model Initiative (CCMI-1) and, later, for phase 6 of the Coupled Model Intercomparison Project (CMIP6) two such stratospheric aerosol data sets were compiled, whose functional capability and representativeness are compared here. For CCMI-1, the SAGE-4λ data set was compiled, which hinges on the measurements at four wavelengths of the SAGE (Stratospheric Aerosol and Gas Experiment) II satellite instrument and uses ground-based Lidar measurements for gap-filling immediately after the Mt. Pinatubo eruption, when the stratosphere was optically opaque for SAGE II. For CMIP6, the new SAGE-3λ data set was compiled, which excludes the least reliable SAGE II wavelength and uses CLAES (Cryogenic Limb Array Etalon Spectrometer) measurements on UARS, the Upper Atmosphere Research Satellite, for gap-filling following the Mt. Pinatubo eruption instead of ground-based Lidars. Here, we performed SOCOLv3 (Solar Climate Ozone Links version 3) chemistry-climate model simulations of the recent past (1986–2005) to investigate the impact of the Mt. Pinatubo eruption in 1991 on stratospheric temperature and ozone and how this response differs depending on which aerosol data set is applied. The use of SAGE-4λ results in heating and ozone loss being overestimated in the lower stratosphere compared to observations in the post-eruption period by approximately 3 K and 0.2 ppmv, respectively. However, less heating occurs in the model simulations based on SAGE-3λ, because the improved gap-filling procedures after the eruption lead to less aerosol loading in the tropical lower stratosphere. As a result, simulated temperature anomalies in the model simulations based on SAGE-3λ for CMIP6 are in excellent agreement with MERRA and ERA-Interim reanalyses in the post-eruption period. Less heating in the simulations with SAGE-3λ means that the rate of tropical upwelling does not strengthen as much as it does in the simulations with SAGE-4λ, which limits dynamical uplift of ozone and therefore provides more time for ozone to accumulate in tropical mid-stratospheric air. Ozone loss following the Mt. Pinatubo eruption is overestimated by 0.1 ppmv in the model simulations based on SAGE-3λ, which is a better agreement with observations than in the simulations based on SAGE-4λ. Overall, the CMIP6 stratospheric aerosol data set, SAGE-3λ, allows SOCOLv3 to more accurately simulate the post-Pinatubo eruption period.



2005 ◽  
Vol 35 (1) ◽  
pp. 13-32 ◽  
Author(s):  
A. Birol Kara ◽  
Alan J. Wallcraft ◽  
Harley E. Hurlburt

Abstract A 1/25° × 1/25° cos(lat) (longitude × latitude) (≈3.2-km resolution) eddy-resolving Hybrid Coordinate Ocean Model (HYCOM) is introduced for the Black Sea and used to examine the effects of ocean turbidity on upper-ocean circulation features including sea surface height and mixed layer depth (MLD) on annual mean climatological time scales. The model is a primitive equation model with a K-profile parameterization (KPP) mixed layer submodel. It uses a hybrid vertical coordinate that combines the advantages of isopycnal, σ, and z-level coordinates in optimally simulating coastal and open-ocean circulation features. This model approach is applied to the Black Sea for the first time. HYCOM uses a newly developed time-varying solar penetration scheme that treats attenuation as a continuous quantity. This scheme includes two bands of solar radiation penetration, one that is needed in the top 10 m of the water column and another that penetrates to greater depths depending on the turbidity. Thus, it is suitable for any ocean general circulation model that has fine vertical resolution near the surface. With this scheme, the optical depth–dependent attenuation of subsurface heating in HYCOM is given by monthly mean fields for the attenuation of photosynthetically active radiation (kPAR) during 1997–2001. These satellite-based climatological kPAR fields are derived from Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) data for the spectral diffuse attenuation coefficient at 490 nm (k490) and have been processed to have the smoothly varying and continuous coverage necessary for use in the Black Sea model applications. HYCOM simulations are driven by two sets of high-frequency climatological forcing, but no assimilation of ocean data is then used to demonstrate the importance of including spatial and temporal varying attenuation depths for the annual mean prediction of upper-ocean quantities in the Black Sea, which is very turbid (kPAR > 0.15 m−1, in general). Results are reported from three model simulations driven by each atmospheric forcing set using different values for the kPAR. A constant solar-attenuation optical depth of ≈17 m (clear water assumption), as opposed to using spatially and temporally varying attenuation depths, changes the surface circulation, especially in the eastern Black Sea. Unrealistic sub–mixed layer heating in the former results in weaker stratification at the base of the mixed layer and a deeper MLD than observed. As a result, the deep MLD off Sinop (at around 42.5°N, 35.5°E) weakens the surface currents regardless of the atmospheric forcing used in the model simulations. Using the SeaWiFS-based monthly turbidity climatology gives a shallower MLD with much stronger stratification at the base and much better agreement with observations. Because of the high Black Sea turbidity, the simulation with all solar radiation absorbed at the surface case gives results similar to the simulations using turbidity from SeaWiFS in the annual means, the aspect of the results investigated in this paper.



2011 ◽  
Vol 11 (24) ◽  
pp. 12773-12786 ◽  
Author(s):  
S. Dhomse ◽  
M. P. Chipperfield ◽  
W. Feng ◽  
J. D. Haigh

Abstract. We have used an off-line 3-D chemical transport model (CTM) to investigate the 11-yr solar cycle response in tropical stratospheric ozone. The model is forced with European Centre for Medium-Range Weather Forecasts (ECMWF) (re)analysis (ERA-40/operational and ERA-Interim) data for the 1979–2005 time period. We have compared the modelled solar response in ozone to observation-based data sets that are constructed using satellite instruments such as Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter UltraViolet instrument (SBUV), Stratospheric Aerosol and Gas Experiment (SAGE) and Halogen Occultation Experiment (HALOE). A significant difference is seen between simulated and observed ozone during the 1980s, which is probably due to inhomogeneities in the ERA-40 reanalyses. In general, the model with ERA-Interim dynamics shows better agreement with the observations from 1990 onwards than with ERA-40. Overall both standard model simulations are partially able to simulate a "double peak"-structured ozone solar response with a minimum around 30 km, and these are in better agreement with HALOE than SAGE-corrected SBUV (SBUV/SAGE) or SAGE-based data sets. In the tropical lower stratosphere (TLS), the modelled solar response with time-varying aerosols is amplified through aliasing with a volcanic signal, as the model overestimates ozone loss during high aerosol loading years. However, the modelled solar response with fixed dynamics and constant aerosols shows a positive signal which is in better agreement with SBUV/SAGE and SAGE-based data sets in the TLS. Our model simulations suggests that photochemistry contributes to the ozone solar response in this region. The largest model-observation differences occur in the upper stratosphere where SBUV/SAGE and SAGE-based data show a significant (up to 4%) solar response whereas the standard model and HALOE do not. This is partly due to a positive solar response in the ECMWF upper stratospheric temperatures which reduces the modelled ozone signal. The large positive upper stratospheric solar response seen in SBUV/SAGE and SAGE-based data can be reproduced in model runs with fixed dynamical fields (i.e. no inter-annual meteorological changes). As these runs effectively assume no long-term temperature changes (solar-induced or otherwise), it should provide an upper limit of the ozone solar response. Overall, full quantification of the solar response in stratospheric ozone is limited by differences in the observed data sets and by uncertainties in the solar response in stratospheric temperatures.



Author(s):  
Patrick A. Plonski ◽  
Pratap Tokekar ◽  
Volkan Isler


2021 ◽  
pp. 1-13
Author(s):  
Kehan Li

Climate change is of great importance in modern times and global warming is considered as a significant part of climate change. It is proved that human’s emissions such as greenhouse gases are one of the main sources of global warming (IPCC, 2018). Apart from greenhouse gases, there is another kind of matter being released in quantity via emissions from industries and transportations and playing an important role in global warming, which is aerosol. However, atmospheric aerosols have the net effect of cooling towards global warming. In this paper, climate change with respect to global warming is briefly introduced and the role of aerosols in the atmosphere is emphasized. Besides, properties of aerosols including dynamics and thermodynamics of aerosols as well as interactions with solar radiation are concluded. In the end, environmental policies and solutions are discussed. Keywords: Climate change, Global warming, Atmospheric aerosols, Particulate matter, Radiation, Environmental policy.



2020 ◽  
Vol 7 (1) ◽  
pp. 37-40
Author(s):  
Arunprasad S ◽  
Saravanan P ◽  
Arulraj R

Solar dryers are equipment and using solar energy for drying substances, especially food. There are two common types of solar dryers: Direct & indirect. This is a dryer type in which the product to be dried directly absorbs the solar radiation. It is also referred to as a natural convection cabinet dryer, because the solar radiation falls directly on the surface; the product quality is reduced. Heated air from the drying chamber is blown through. A solar dryer's basic function is to heat air with solar energy to a constant temperature, which enables the moisture extraction from crops within a drying chamber. The main objective of flat plate solar air dryer model based on without tray & with tray chamber in Creo parametric software & computational fluid dynamics in Ansys software. Generally, solar air dryer is heat loss is possible, so it’s reduced with help of insulation material (glass wool & polyurethane). To predict the temperature difference in various air flow with insulation material. Furthermore, choose the better insulation material & difference between with & without tray chamber.



Author(s):  
Sundhy Pareza ◽  
Purwantono Purwantono ◽  
Remon Lapisa ◽  
Primawati Primawati

The issue of global warming is very strong in the force in the procession, the damage caused by global warming is very influential in the survival of living beings. The methods performed in this study are experimental methods. The experiments performed were to make a design and to become a unity so that it formed a tool of electric bicycle transportation that can be used well. This thesis author devise and assemble electric bicycle using DC electric motor 24 Volt 250 Watt and 3000 rpm. The power system used is 24 Volt 12 Ampere battery. From the results of the test and analysis of data that has been taken on the electric bicycle obtained data of the average speed obtained by the electric bike with a load of 78 = 4.94 m/s, load 83 = 4.59 m/s, load 88 = 4.25 m/s, power output to drive electric bicycle with load 78 = 266.679 Watt, load 83 = 263.810 Watt, load 88 = 258.984 Watt. Isu pemanasan global sangat kuat di gencar disuarakan, kerusakan yang disebabkan pemanasan global sangat berpengaruh pada kelangsungan hidup makluk hidup. Metode yang dilakukan dalam penelitian ini adalah metode eksperimen. Eksperimen yang dilakukan adalah membuat sebuah rancangan dan merakitnya menjadi suatu kesatuan sehingga terbentuk sebuah alat transportasi sepeda listrikyang dapat digunakan dengan baik. Skripsi ini penulis merancang dan merakit sepeda listrik dengan menggunakan motor listrik DC 24 Volt 250 Watt dan 3000 rpm. Sistem daya yang digunakan adalah baterai 24 Volt 12 Ampere. Dari hasil pengujian dan analisis data yang telah diambil pada sepeda listrik didapatkan data berupa kecepatan rata-rata yang didapatkan sepeda listrik dengan beban 78 = 4,94 m/s, beban 83 = 4,59 m/s, beban 88 = 4,25 m/s, daya output untuk menggerakkan sepeda listrik  dengan beban 78 = 266,679 Watt, beban 83 = 263,810 Watt, beban 88 = 258,984 Watt.



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