Investigation of the Surface and Circulation Impacts of Cloud-Brightening Geoengineering

Projected increases in greenhouse gases have prompted serious discussion on geoengineering the climate system to counteract global climate change. Cloud albedo enhancement has been proposed as a feasible geoengineering approach, but previous research suggests undesirable consequences of globally uniform cloud brightening. The present study uses GFDL’s Climate Model version 2G (CM2G) global coupled model to simulate cloud albedo enhancement via increases in cloud condensation nuclei (CCN) to 1000 cm−3 targeted at the marine stratus deck of the Pacific Ocean, where persistent low clouds suggest a regional approach to cloud brightening. The impact of this regional geoengineering on global circulation and climate in the presence of a 1% annual increase of CO2 was investigated. Surface temperatures returned to near preindustrial levels over much of the globe with cloud modifications in place. In the first 40 years and over the 140-yr mean, significant cooling over the equatorial Pacific, continued Arctic warming, large precipitation changes over the western Pacific, and a westward compression and intensification of the Walker circulation were observed in response to cloud brightening. The cloud brightening caused a persistent La Niña condition associated with an increase in hurricane maximum potential intensity and genesis potential index, and decreased vertical wind shear between July and November in the tropical Atlantic, South China Sea, and to the east of Japan. Responses were similar with CCN = 500 cm−3.

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The Impact of Climate Change on Meningitis in Northwest Nigeria: An Assessment Using CMIP5 Climate Model Simulations

Weather Climate and Society ◽

10.1175/wcas-d-13-00068.1 ◽

2014 ◽

Vol 6 (3) ◽

pp. 371-379 ◽

Cited By ~ 9

Author(s):

Auwal F. Abdussalam ◽

Andrew J. Monaghan ◽

Daniel F. Steinhoff ◽

Vanja M. Dukic ◽

Mary H. Hayden ◽

...

Keyword(s):

Climate Change ◽

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Treatment Strategies ◽

Coupled Model ◽

Annual Incidence ◽

Future Climate ◽

Future Climate Change ◽

The Impact

Abstract Meningitis remains a major health burden throughout Sahelian Africa, especially in heavily populated northwest Nigeria with an annual incidence rate ranging from 18 to 200 per 100 000 people for 2000–11. Several studies have established that cases exhibit sensitivity to intra- and interannual climate variability, peaking during the hot and dry boreal spring months, raising concern that future climate change may increase the incidence of meningitis in the region. The impact of future climate change on meningitis risk in northwest Nigeria is assessed by forcing an empirical model of meningitis with monthly simulations of seven meteorological variables from an ensemble of 13 statistically downscaled global climate model projections from phase 5 of the Coupled Model Intercomparison Experiment (CMIP5) for representative concentration pathway (RCP) 2.6, 6.0, and 8.5 scenarios, with the numbers representing the globally averaged top-of-the-atmosphere radiative imbalance (in W m−2) in 2100. The results suggest future temperature increases due to climate change have the potential to significantly increase meningitis cases in both the early (2020–35) and late (2060–75) twenty-first century, and for the seasonal onset of meningitis to begin about a month earlier on average by late century, in October rather than November. Annual incidence may increase by 47% ± 8%, 64% ± 9%, and 99% ± 12% for the RCP 2.6, 6.0, and 8.5 scenarios, respectively, in 2060–75 with respect to 1990–2005. It is noteworthy that these results represent the climatological potential for increased cases due to climate change, as it is assumed that current prevention and treatment strategies will remain similar in the future.

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Uncertainty of climate change and its impact on reference evapotranspiration in Rasht City, Iran

Journal of Water and Climate Change ◽

10.2166/wcc.2011.055 ◽

2011 ◽

Vol 2 (1) ◽

pp. 72-83 ◽

Cited By ~ 4

Author(s):

Heerbod Jahanbani ◽

Lee Teang Shui ◽

Alireza Massah Bavani ◽

Abdul Halim Ghazali

Keyword(s):

Climate Change ◽

General Circulation ◽

Climate Model ◽

Reference Evapotranspiration ◽

Global Climate ◽

Global Climate Model ◽

Coupled Model ◽

General Circulation Models ◽

Model Version ◽

The Impact

There are many factors of uncertainty regarding the impact of climate change on reference evapotranspiration (ETo). The accuracy of the results is strictly related to these factors and ignoring any one of them reduces the precision of the results, and reduces their applicability for decision makers. In this study, the uncertainty related to two ETo models, the Hargreaves-Samani (HGS) and Artificial Neural Network (ANN), and two Atmosphere-Ocean General Circulation Models (AOGCMs), Hadley Centre Coupled Model, version 3 (HadCM3) climatic model and the Canadian Global Climate Model, version 3 (CGCM3) climatic model under climate change, was evaluated. The models predicted average temperature increases by 2010 to 2039 of 0.95 °C by the HadCM3 model and 1.13°C by the CGCM3 model under the A2 scenario relative to observed temperature. Accordingly, the models predicted average ETo would increase of 0.48, 0.60, 0.50 and 0.60 (mm/day) by 2010 to 2039 projected by four methods (by introducing the temperature of the HadCM3-A2 model and the CGCM3-A2 to ANN and HGS) relative to ETo of the observed period. The results showed that uncertainty of the AOGCMs is more than that of the ETo models applied in this study.

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Brightening of the global cloud field by nitric acid and the associated radiative forcing

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-5225-2012 ◽

2012 ◽

Vol 12 (2) ◽

pp. 5225-5245

Author(s):

R. Makkonen ◽

S. Romakkaniemi ◽

H. Kokkola ◽

P. Stier ◽

P. Räisänen ◽

...

Keyword(s):

Nitric Acid ◽

Indirect Effect ◽

Radiative Forcing ◽

Climate Model ◽

Global Climate ◽

Cloud Condensation Nuclei ◽

Global Climate Model ◽

So2 Emissions ◽

Cloud Albedo ◽

Albedo Effect

Abstract. Clouds cool Earth's climate by reflecting 20 % of the incoming solar energy, while also trapping part of the outgoing radiation. The effect of human activities on clouds is poorly understood, but the present-day anthropogenic cooling via changes of cloud albedo and lifetime could be of the same order as warming from anthropogenic addition in CO2. Soluble trace gases can increase water condensation to particles, possibly leading to activation of smaller aerosols and more numerous cloud droplets. We have studied the effect of nitric acid on the aerosol indirect effect with a global climate model. The nitric acid contribution to the present-day cloud albedo effect was found to be −0.32 W m−2 and the total indirect effect −0.46 W m−2. The contribution to the cloud albedo effect is shown to increase to −0.37 W m−2 by 2100, if considering only the reductions in available cloud condensation nuclei. Overall, the effect of nitric acid can play a large part in aerosol cooling during the following decades with decreasing SO2 emissions and increasing NOx and greenhouse gases.

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Impacts of Ozone Changes in the Tropopause Layer on Stratospheric Water Vapor

Atmosphere ◽

10.3390/atmos12030291 ◽

2021 ◽

Vol 12 (3) ◽

pp. 291

Author(s):

Jinpeng Lu ◽

Fei Xie ◽

Hongying Tian ◽

Jiali Luo

Keyword(s):

Water Vapor ◽

Ozone Depletion ◽

Climate Model ◽

Global Climate ◽

Stratospheric Water Vapor ◽

Radiative Processes ◽

Low Latitudes ◽

Cold Point ◽

The Impact ◽

Tropopause Temperature

Stratospheric water vapor (SWV) changes play an important role in regulating global climate change, and its variations are controlled by tropopause temperature. This study estimates the impacts of tropopause layer ozone changes on tropopause temperature by radiative process and further influences on lower stratospheric water vapor (LSWV) using the Whole Atmosphere Community Climate Model (WACCM4). It is found that a 10% depletion in global (mid-low and polar latitudes) tropopause layer ozone causes a significant cooling of the tropical cold-point tropopause with a maximum cooling of 0.3 K, and a corresponding reduction in LSWV with a maximum value of 0.06 ppmv. The depletion of tropopause layer ozone at mid-low latitudes results in cooling of the tropical cold-point tropopause by radiative processes and a corresponding LSWV reduction. However, the effect of polar tropopause layer ozone depletion on tropical cold-point tropopause temperature and LSWV is opposite to and weaker than the effect of tropopause layer ozone depletion at mid-low latitudes. Finally, the joint effect of tropopause layer ozone depletion (at mid-low and polar latitudes) causes a negative cold-point tropopause temperature and a decreased tropical LSWV. Conversely, the impact of a 10% increase in global tropopause layer ozone on LSWV is exactly the opposite of the impact of ozone depletion. After 2000, tropopause layer ozone decreased at mid-low latitudes and increased at high latitudes. These tropopause layer ozone changes at different latitudes cause joint cooling in the tropical cold-point tropopause and a reduction in LSWV. Clarifying the impacts of tropopause layer ozone changes on LSWV clearly is important for understanding and predicting SWV changes in the context of future global ozone recovery.

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Dynamic Downscaling of the Impact of Climate Change on the Ocean Circulation in the Galápagos Archipelago

Advances in Meteorology ◽

10.1155/2013/837432 ◽

2013 ◽

Vol 2013 ◽

pp. 1-18 ◽

Cited By ~ 7

Author(s):

Yanyun Liu ◽

Lian Xie ◽

John M. Morrison ◽

Daniel Kamykowski

Keyword(s):

Climate Change ◽

Ocean Circulation ◽

Global Climate Change ◽

Climate Model ◽

Global Climate ◽

Ocean Model ◽

Reanalysis Dataset ◽

Equatorial Undercurrent ◽

Galapagos Archipelago ◽

The Impact

The regional impact of global climate change on the ocean circulation around the Galápagos Archipelago is studied using the Hybrid Coordinate Ocean Model (HYCOM) configured for a four-level nested domain system. The modeling system is validated and calibrated using daily atmospheric forcing derived from the NCEP/NCAR reanalysis dataset from 1951 to 2007. The potential impact of future anthropogenic global warming (AGW) in the Galápagos region is examined using the calibrated HYCOM with forcing derived from the IPCC-AR4 climate model. Results show that although the oceanic variability in the entire Galápagos region is significantly affected by global climate change, the degree of such effects is inhomogeneous across the region. The upwelling region to the west of the Isabella Island shows relatively slower warming trends compared to the eastern Galápagos region. Diagnostic analysis suggests that the variability in the western Galápagos upwelling region is affected mainly by equatorial undercurrent (EUC) and Panama currents, while the central/east Galápagos is predominantly affected by both Peru and EUC currents. The inhomogeneous responses in different regions of the Galápagos Archipelago to future AGW can be explained by the incoherent changes of the various current systems in the Galápagos region as a result of global climate change.

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Revisiting the Krakatau 1883 Volcanic Aerosol Dispersal

10.5194/egusphere-egu21-10489 ◽

2021 ◽

Author(s):

Rafael Castro ◽

Tushar Mittal ◽

Stephen Self

Keyword(s):

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Volcanic Eruptions ◽

Climate Impact ◽

Volcanic Plume ◽

Quasi Biennial Oscillation ◽

Aerosol Cloud ◽

Pinatubo Eruption ◽

The Impact

<p>The 1883 Krakatau eruption is one of the most well-known historical volcanic eruptions due to its significant global climate impact as well as first recorded observations of various aerosol associated optical and physical phenomena. Although much work has been done on the former by comparison of global climate model predictions/ simulations with instrumental and proxy climate records, the latter has surprisingly not been studied in similar detail. In particular, there is a wealth of observations of vivid red sunsets, blue suns, and other similar features, that can be used to analyze the spatio-temporal dispersal of volcanic aerosols in summer to winter 1883. Thus, aerosol cloud dispersal after the Krakatau eruption can be estimated, bolstered by aerosol cloud behavior as monitored by satellite-based instrument observations after the 1991 Pinatubo eruption. This is one of a handful of large historic eruptions where this analysis can be done (using non-climate proxy methods). In this study, we model particle trajectories of the Krakatau eruption cloud using the Hysplit trajectory model and compare our results with our compiled observational dataset (principally using Verbeek 1884, the Royal Society report, and Kiessling 1884).</p><p>In particular, we explore the effect of different atmospheric states - the quasi-biennial oscillation (QBO) which impacts zonal movement of the stratospheric volcanic plume - to estimate the phase of the QBO in 1883 required for a fast-moving westward cloud. Since this alone is unable to match the observed latitudinal spread of the aerosols, we then explore the impact of an&#160; umbrella cloud (2000 km diameter) that almost certainly formed during such a large eruption. A large umbrella cloud, spreading over ~18 degrees within the duration of the climax of the eruption (6-8 hours), can lead to much quicker latitudinal spread than a point source (vent). We will discuss the results of the combined model (umbrella cloud and correct QBO phase) with historical accounts and observations, as well as previous work on the 1991 Pinatubo eruption. We also consider the likely impacts of water on aerosol concentrations and the relevance of this process for eruptions with possible significant seawater interactions, like Krakatau. We posit that the role of umbrella clouds is an under-appreciated, but significant, process for beginning to model the climatic impacts of large volcanic eruptions.</p>

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Impact of Resolution on the Tropical Pacific Circulation in a Matrix of Coupled Models

Journal of Climate ◽

10.1175/2008jcli2537.1 ◽

2009 ◽

Vol 22 (10) ◽

pp. 2541-2556 ◽

Cited By ~ 69

Author(s):

Malcolm J. Roberts ◽

A. Clayton ◽

M.-E. Demory ◽

J. Donners ◽

P. L. Vidale ◽

...

Keyword(s):

Coupled Model ◽

Walker Circulation ◽

Ocean Model ◽

Tropical Pacific ◽

Coupled Models ◽

Model Stability ◽

The Mean ◽

The Impact ◽

Mean State ◽

The Tropical Pacific

Abstract Results are presented from a matrix of coupled model integrations, using atmosphere resolutions of 135 and 90 km, and ocean resolutions of 1° and 1/3°, to study the impact of resolution on simulated climate. The mean state of the tropical Pacific is found to be improved in the models with a higher ocean resolution. Such an improved mean state arises from the development of tropical instability waves, which are poorly resolved at low resolution; these waves reduce the equatorial cold tongue bias. The improved ocean state also allows for a better simulation of the atmospheric Walker circulation. Several sensitivity studies have been performed to further understand the processes involved in the different component models. Significantly decreasing the horizontal momentum dissipation in the coupled model with the lower-resolution ocean has benefits for the mean tropical Pacific climate, but decreases model stability. Increasing the momentum dissipation in the coupled model with the higher-resolution ocean degrades the simulation toward that of the lower-resolution ocean. These results suggest that enhanced ocean model resolution can have important benefits for the climatology of both the atmosphere and ocean components of the coupled model, and that some of these benefits may be achievable at lower ocean resolution, if the model formulation allows.

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Climate SPHINX: evaluating the impact of resolution and stochastic physics parameterisations in the EC-Earth global climate model

Geoscientific Model Development ◽

10.5194/gmd-10-1383-2017 ◽

2017 ◽

Vol 10 (3) ◽

pp. 1383-1402 ◽

Cited By ~ 35

Author(s):

Paolo Davini ◽

Jost von Hardenberg ◽

Susanna Corti ◽

Hannah M. Christensen ◽

Stephan Juricke ◽

...

Keyword(s):

High Resolution ◽

Large Scale ◽

Climate Model ◽

Global Climate ◽

Rainfall Variability ◽

Global Climate Model ◽

Small Scale ◽

Low Resolution ◽

The Impact ◽

Stochastic Physics

Abstract. The Climate SPHINX (Stochastic Physics HIgh resolutioN eXperiments) project is a comprehensive set of ensemble simulations aimed at evaluating the sensitivity of present and future climate to model resolution and stochastic parameterisation. The EC-Earth Earth system model is used to explore the impact of stochastic physics in a large ensemble of 30-year climate integrations at five different atmospheric horizontal resolutions (from 125 up to 16 km). The project includes more than 120 simulations in both a historical scenario (1979–2008) and a climate change projection (2039–2068), together with coupled transient runs (1850–2100). A total of 20.4 million core hours have been used, made available from a single year grant from PRACE (the Partnership for Advanced Computing in Europe), and close to 1.5 PB of output data have been produced on SuperMUC IBM Petascale System at the Leibniz Supercomputing Centre (LRZ) in Garching, Germany. About 140 TB of post-processed data are stored on the CINECA supercomputing centre archives and are freely accessible to the community thanks to an EUDAT data pilot project. This paper presents the technical and scientific set-up of the experiments, including the details on the forcing used for the simulations performed, defining the SPHINX v1.0 protocol. In addition, an overview of preliminary results is given. An improvement in the simulation of Euro-Atlantic atmospheric blocking following resolution increase is observed. It is also shown that including stochastic parameterisation in the low-resolution runs helps to improve some aspects of the tropical climate – specifically the Madden–Julian Oscillation and the tropical rainfall variability. These findings show the importance of representing the impact of small-scale processes on the large-scale climate variability either explicitly (with high-resolution simulations) or stochastically (in low-resolution simulations).

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Influence of Ocean and Atmosphere Components on Simulated Climate Sensitivities

Journal of Climate ◽

10.1175/jcli-d-12-00121.1 ◽

2013 ◽

Vol 26 (1) ◽

pp. 231-245 ◽

Cited By ~ 27

Author(s):

Michael Winton ◽

Alistair Adcroft ◽

Stephen M. Griffies ◽

Robert W. Hallberg ◽

Larry W. Horowitz ◽

...

Keyword(s):

Sea Ice ◽

Climate Models ◽

Climate Model ◽

Model Simulation ◽

Coupled Model ◽

Ocean Model ◽

Historical Simulation ◽

Model Version ◽

Salinity Response ◽

The Impact

Abstract The influence of alternative ocean and atmosphere subcomponents on climate model simulation of transient sensitivities is examined by comparing three GFDL climate models used for phase 5 of the Coupled Model Intercomparison Project (CMIP5). The base model ESM2M is closely related to GFDL’s CMIP3 climate model version 2.1 (CM2.1), and makes use of a depth coordinate ocean component. The second model, ESM2G, is identical to ESM2M but makes use of an isopycnal coordinate ocean model. The authors compare the impact of this “ocean swap” with an “atmosphere swap” that produces the GFDL Climate Model version 3 (CM3) by replacing the AM2 atmospheric component with AM3 while retaining a depth coordinate ocean model. The atmosphere swap is found to have much larger influence on sensitivities of global surface temperature and Northern Hemisphere sea ice cover. The atmosphere swap also introduces a multidecadal response time scale through its indirect influence on heat uptake. Despite significant differences in their interior ocean mean states, the ESM2M and ESM2G simulations of these metrics of climate change are very similar, except for an enhanced high-latitude salinity response accompanied by temporarily advancing sea ice in ESM2G. In the ESM2G historical simulation this behavior results in the establishment of a strong halocline in the subpolar North Atlantic during the early twentieth century and an associated cooling, which are counter to observations in that region. The Atlantic meridional overturning declines comparably in all three models.

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Assessing the impact of global warming on worldwide open field tomato cultivation through CSIRO-Mk3·0 global climate model

The Journal of Agricultural Science ◽

10.1017/s0021859616000654 ◽

2016 ◽

Vol 155 (3) ◽

pp. 407-420 ◽

Cited By ~ 7

Author(s):

R. S. SILVA ◽

L. KUMAR ◽

F. SHABANI ◽

M. C. PICANÇO

Keyword(s):

Climate Change ◽

Global Warming ◽

Open Field ◽

Climate Models ◽

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Current Model ◽

Global Climate Models ◽

The Impact

SUMMARYTomato (Solanum lycopersicum L.) is one of the most important vegetable crops globally and an important agricultural sector for generating employment. Open field cultivation of tomatoes exposes the crop to climatic conditions, whereas greenhouse production is protected. Hence, global warming will have a greater impact on open field cultivation of tomatoes rather than the controlled greenhouse environment. Although the scale of potential impacts is uncertain, there are techniques that can be implemented to predict these impacts. Global climate models (GCMs) are useful tools for the analysis of possible impacts on a species. The current study aims to determine the impacts of climate change and the major factors of abiotic stress that limit the open field cultivation of tomatoes in both the present and future, based on predicted global climate change using CLIMatic indEX and the A2 emissions scenario, together with the GCM Commonwealth Scientific and Industrial Research Organisation (CSIRO)-Mk3·0 (CS), for the years 2050 and 2100. The results indicate that large areas that currently have an optimum climate will become climatically marginal or unsuitable for open field cultivation of tomatoes due to progressively increasing heat and dry stress in the future. Conversely, large areas now marginal and unsuitable for open field cultivation of tomatoes will become suitable or optimal due to a decrease in cold stress. The current model may be useful for plant geneticists and horticulturalists who could develop new regional stress-resilient tomato cultivars based on needs related to these modelling projections.

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