scholarly journals Urban heat island amplification estimates on global warming using an albedo model

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Alec Feinberg
Keyword(s):  
Global Warming ◽  
Radiative Forcing ◽  
Global Scale ◽  
Arctic Sea Ice ◽  
Worst Case ◽  
Basic Model ◽  
Urban Heat ◽  
New Perspective ◽  
Arctic Sea Ice Loss ◽  
The Impact

AbstractIn this paper, we provide nominal and worst-case estimates of radiative forcing due to the UHI effect using a Weighted Amplification Albedo Solar Urbanization model. This calculation is done with the help of reported findings from UHI footprint and heat dome studies that simplify estimates for UHI amplification factors. Using this method, we quantify a global warming range due to the UHI effect, including its extent. Forcing estimates varied approximately between 0.07 and 0.87 W/m2 representing 3% to 36% of global warming relative to the greenhouse gas forcing estimates between 1950 and 2019. Variations in our model are due to the urbanized area and associated UHI amplification estimate uncertainties. However, the model showed consistent values of about 0.16 W/m2/% solar effective amplified areas and 1.6 W/m2/%Δalbedo for the urbanized coverage forcing values. The basic model is additionally used to quantify feedback warming due to Arctic sea ice loss. Feedback estimates contribute to the impact of UHI forcing assessments. From our median estimates, it is concluded that UHIs contribute significantly to global warming trends. The model is versatile and also provides UHI albedo reverse forcing assessments. The results provide insight into the UHI area effects from a new perspective using a global view albedo model compared to prior ground-based measurement studies. It also illustrates the utility of using effective UHI amplification estimates when assessing their warming effect on a global scale.

scholarly journals A Link between the Hiatus in Global Warming and North American Drought

2015 ◽  
Vol 28 (9) ◽  
pp. 3834-3845 ◽  
Author(s):  
Thomas L. Delworth ◽  
Fanrong Zeng ◽  
Anthony Rosati ◽  
Gabriel A. Vecchi ◽  
Andrew T. Wittenberg
Keyword(s):  
Global Warming ◽  
North America ◽  
Surface Temperature ◽  
North American ◽  
Radiative Forcing ◽  
Tropical Pacific ◽  
Global Warming Hiatus ◽  
Warming Hiatus ◽  
The Impact ◽  
The Tropical Pacific

Abstract Portions of western North America have experienced prolonged drought over the last decade. This drought has occurred at the same time as the global warming hiatus—a decadal period with little increase in global mean surface temperature. Climate models and observational analyses are used to clarify the dual role of recent tropical Pacific changes in driving both the global warming hiatus and North American drought. When observed tropical Pacific wind stress anomalies are inserted into coupled models, the simulations produce persistent negative sea surface temperature anomalies in the eastern tropical Pacific, a hiatus in global warming, and drought over North America driven by SST-induced atmospheric circulation anomalies. In the simulations herein the tropical wind anomalies account for 92% of the simulated North American drought during the recent decade, with 8% from anthropogenic radiative forcing changes. This suggests that anthropogenic radiative forcing is not the dominant driver of the current drought, unless the wind changes themselves are driven by anthropogenic radiative forcing. The anomalous tropical winds could also originate from coupled interactions in the tropical Pacific or from forcing outside the tropical Pacific. The model experiments suggest that if the tropical winds were to return to climatological conditions, then the recent tendency toward North American drought would diminish. Alternatively, if the anomalous tropical winds were to persist, then the impact on North American drought would continue; however, the impact of the enhanced Pacific easterlies on global temperature diminishes after a decade or two due to a surface reemergence of warmer water that was initially subducted into the ocean interior.

scholarly journals The impact of Arctic sea ice loss on mid-Holocene climate

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Hyo-Seok Park ◽  
Seong-Joong Kim ◽  
Kyong-Hwan Seo ◽  
Andrew L. Stewart ◽  
Seo-Yeon Kim ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Holocene Climate ◽  
Arctic Sea ◽  
Arctic Sea Ice Loss ◽  
The Impact

The Impact of Pavement Albedo on Radiative Forcing and Building Energy Demand: Comparative Analysis of Urban Neighborhoods

2018 ◽  
Vol 2672 (40) ◽  
pp. 88-96
Author(s):  
Xin Xu ◽  
Jeremy Gregory ◽  
Randolph Kirchain
Keyword(s):  
Global Warming ◽  
Comparative Analysis ◽  
Radiative Forcing ◽  
Energy Demand ◽  
Building Energy ◽  
Urban Neighborhoods ◽  
Urban Morphology ◽  
Model Framework ◽  
The Impact ◽  
Reflective Surfaces

Albedo is the measure of the ratio of solar radiation reflected by the Earth’s surface. High-albedo reflective surfaces absorb less energy and reflect more shortwave radiation. The change in radiative energy balance at the top-of-atmosphere (TOA), which is called radiative forcing (RF), reduces nearby air temperatures and influences the surrounding building energy demand (BED). The impact of reflective surfaces on RF and BED has been investigated separately by researchers through modeling and observational studies, however, no one has compared RF and BED impacts under the same context and the net effect of these two phenomena remains unclear. This paper presents a comprehensive approach to assess the net impacts of pavement albedo modification strategies in selected urban neighborhoods. We apply an adapted analytical model for RF and a hybrid model framework combining two different models for BED to estimate the impacts of increasing pavement albedo from 0.1 to 0.3 for different urban neighborhoods in Boston and Phoenix. The impact of several context-specific factors, including location, urban morphology, shadings etc., are taken into account in the models. Comparative analysis reveals that the net impact of changing pavement albedo can vary from one neighborhood to another. In Phoenix downtown, reflective pavements create net global warming potential burdens, while increasing pavement albedo results in potential savings in the Boston downtown area. This work provides insights into pavement albedo impacts at urban scale and supports more informed decisions on pavement designs that save energy and counteract some of the effects of global warming.

scholarly journals The Ocean’s Role in Continental Climate Variability and Change

2009 ◽  
Vol 22 (18) ◽  
pp. 4939-4952 ◽  
Author(s):  
Dietmar Dommenget
Keyword(s):  
Global Warming ◽  
Climate Variability ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Radiative Forcing ◽  
Global Scale ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Continental Climate

Abstract A characteristic feature of global warming is the land–sea contrast, with stronger warming over land than over oceans. Recent studies find that this land–sea contrast also exists in equilibrium global change scenarios, and it is caused by differences in the availability of surface moisture over land and oceans. In this study it is illustrated that this land–sea contrast exists also on interannual time scales and that the ocean–land interaction is strongly asymmetric. The land surface temperature is more sensitive to the oceans than the oceans are to the land surface temperature, which is related to the processes causing the land–sea contrast in global warming scenarios. It suggests that the ocean’s natural variability and change is leading to variability and change with enhanced magnitudes over the continents, causing much of the longer-time-scale (decadal) global-scale continental climate variability. Model simulations illustrate that continental warming due to anthropogenic forcing (e.g., the warming at the end of the last century or future climate change scenarios) is mostly (80%–90%) indirectly forced by the contemporaneous ocean warming, not directly by local radiative forcing.

scholarly journals Consequences of accelerated Global Warming on nature and economy and the remedies for Global Green Economy

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Navneet Gera
Keyword(s):  
Global Warming ◽  
Human Resource ◽  
Co2 Emission ◽  
Global Scale ◽  
Green Economy ◽  
Oil Consumption ◽  
Root Cause ◽  
Global Issue ◽  
The Impact

Abstract: Global warming is the problem of 21st century for the globe. The root cause of problem is heavy oil consumption, deforestation, CO2 emission due to human and industrial activities and the rising threats of globalization like terrorism etc. This paper will address the impact of global warming on the Industries, human resource and the flora and fauna. The human resource has made a significant change in the current environment with the collective use of industries and the other GHG (Green House Gases) causing disturbance in the environment. In addition, the human resource is thinking on this issue, as it has become a global issue. There have been initiatives taken on Global Scale when Kyoto protocol agreement was signed which is in continuation till 2012. There have been further initiatives when the Ministers from across the global met at Copenhagen but at the end of the end there have been no discrete plans for Global Warming. Though it is a problem but how certainly can we manage this is more important. Global warming solutions can reduce the amount of heat-trapping gases that we emit into the atmosphere. Among the solutions, is a model G2I3 addressed in this paper and the role of every Individual which can make a great impact on the environmental problems.

scholarly journals Mechanisms of Stratospheric and Tropospheric Circulation Response to Projected Arctic Sea Ice Loss*

2015 ◽  
Vol 28 (19) ◽  
pp. 7824-7845 ◽  
Author(s):  
Lantao Sun ◽  
Clara Deser ◽  
Robert A. Tomas
Keyword(s):  
Sea Ice ◽  
Polar Vortex ◽  
Arctic Sea Ice ◽  
Climate Impacts ◽  
Negative Phase ◽  
Surface Boundary ◽  
Arctic Sea ◽  
Tropospheric Circulation ◽  
Arctic Sea Ice Loss ◽  
The Impact

Abstract The impact of projected Arctic sea ice loss on the atmospheric circulation is investigated using the Whole Atmosphere Community Climate Model (WACCM), a model with a well-resolved stratosphere. Two 160-yr simulations are conducted: one with surface boundary conditions fixed at late twentieth-century values and the other with identical conditions except for Arctic sea ice, which is prescribed at late twenty-first-century values. Their difference isolates the impact of future Arctic sea ice loss upon the atmosphere. The tropospheric circulation response to the imposed ice loss resembles the negative phase of the northern annular mode, with the largest amplitude in winter, while the less well-known stratospheric response transitions from a slight weakening of the polar vortex in winter to a strengthening of the vortex in spring. The lack of a significant winter stratospheric circulation response is shown to be a consequence of largely cancelling effects from sea ice loss in the Atlantic and Pacific sectors, which drive opposite-signed changes in upward wave propagation from the troposphere to the stratosphere. Identical experiments conducted with Community Atmosphere Model, version 4, WACCM’s low-top counterpart, show a weaker tropospheric response and a different stratospheric response compared to WACCM. An additional WACCM experiment in which the imposed ice loss is limited to August–November reveals that autumn ice loss weakens the stratospheric polar vortex in January, followed by a small but significant tropospheric response in late winter and early spring that resembles the negative phase of the North Atlantic Oscillation, with attendant surface climate impacts.

Respective roles of direct GHG radiative forcing and induced Arctic sea ice loss on the Northern Hemisphere atmospheric circulation

2017 ◽  
Vol 49 (11-12) ◽  
pp. 3693-3713 ◽  
Author(s):  
Thomas Oudar ◽  
Emilia Sanchez-Gomez ◽  
Fabrice Chauvin ◽  
Julien Cattiaux ◽  
Laurent Terray ◽  
...  
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Radiative Forcing ◽  
Arctic Sea Ice ◽  
Arctic Sea ◽  
Arctic Sea Ice Loss

scholarly journals Atmospheric feedback explains disparate climate response to regional Arctic sea-ice loss

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xavier J. Levine ◽  
Ivana Cvijanovic ◽  
Pablo Ortega ◽  
Markus G. Donat ◽  
Etienne Tourigny
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Sea Ice ◽  
Feedback Mechanism ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Climate Response ◽  
Arctic Sea ◽  
Arctic Sea Ice Loss ◽  
Atmospheric Feedback

AbstractArctic sea-ice loss is a consequence of anthropogenic global warming and can itself be a driver of climate change in the Arctic and at lower latitudes, with sea-ice minima likely favoring extreme events over Europe and North America. Yet the role that the sea-ice plays in ongoing climate change remains uncertain, partly due to a limited understanding of whether and how the exact geographical distribution of sea-ice loss impacts climate. Here we demonstrate that the climate response to sea-ice loss can vary widely depending on the pattern of sea-ice change, and show that this is due to the presence of an atmospheric feedback mechanism that amplifies the local and remote signals when broader scale sea-ice loss occurs. Our study thus highlights the need to better constrain the spatial pattern of future sea-ice when assessing its impacts on the climate in the Arctic and beyond.

Impact of Clouds on Broadband Radiation Profiles in the Summer Arctic Measured by a Tethered Balloon During MOSAiC: First Results

2021 ◽  
Author(s):  
Michael Lonardi ◽  
Christian Pilz ◽  
Ulrike Egerer ◽  
André Ehrlich ◽  
Matthew D. Shupe ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Radiative Forcing ◽  
Arctic Sea Ice ◽  
Radiative Heating ◽  
The Arctic ◽  
Radiative Energy ◽  
Tethered Balloon ◽  
Local Cooling ◽  
Airborne Measurements ◽  
The Impact

<p>Arctic boundary layer clouds play an important role in the Arctic amplification due to their impact on the radiative energy budget, e. g., local cooling at cloud top which strongly affects boundary-layer dynamics. High resolution in-situ data characterizing the irradiance profile in clouds over the Arctic sea ice are rare due to the accessibility of this region, the challenges posed by icing and the limited resolution of airborne measurements.</p><p>The tethered balloon system BELUGA (Balloon-bornE moduLar Utility for profilinG the lower Atmosphere) was deployed from the ice camp of the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC) in July 2020. BELUGA consists of a 90 m³ helium-filled tethered balloon with maximum flight altitude of 1500 m and an adaptable scientific payload to characterize radiation, cloud, aerosol and turbulence properties which was specifically developed for Arctic tethered balloon operations.</p><p>Here a first analysis of vertical profiles of upwards and downwards solar and terrestrial irradiances in cloudy and cloud-free conditions is presented. Profiles of radiative heating were calculated and compared for different cloud covers. The case studies were evaluated by radiative transfer simulations  to quantify the impact of different cloud and atmospheric properties on the heating rate profiles. In combination with surface-based measurements, the cloud radiative forcing in the summer Arctic was assessed.</p>

Toward Robust Monitoring of Malicious Outbreaks

2021 ◽  
Author(s):  
Shaojie Tang ◽  
Siyuan Liu ◽  
Xu Han ◽  
Yu Qiao
Keyword(s):  
Social Networks ◽  
Recent Work ◽  
Diffusion Model ◽  
Diffusion Processes ◽  
Worst Case ◽  
Computer Worms ◽  
Robust Solutions ◽  
Basic Model ◽  
Security Games ◽  
The Impact

Recently, diffusion processes in social networks have attracted increasing attention within computer science, marketing science, social sciences, and political science. Although the majority of existing works focus on maximizing the reach of desirable diffusion processes, we are interested in deploying a group of monitors to detect malicious diffusion processes such as the spread of computer worms. In this work, we introduce and study the [Formula: see text]-Monitoring Game} on networks. Our game is composed of two parties an attacker and a defender. The attacker can launch an attack by distributing a limited number of seeds (i.e., virus) to the network. Under our [Formula: see text]-Monitoring Game, we say an attack is successful if and only if the following two conditions are satisfied: (1) the outbreak/propagation reaches at least α individuals without intervention, and (2) it has not been detected before reaching β individuals. Typically, we require that β is no larger than α in order to compensate the reaction delays after the outbreak has been detected. On the other end, the defender’s ultimate goal is to deploy a set of monitors in the network that can minimize attacker’s success ratio in the worst-case. (We also extend the basic model by considering a noisy diffusion model, where the propagation probabilities on each edge could vary within an interval.) Our work is built upon recent work in security games, our adversarial setting provides robust solutions in practice. Summary of Contribution: Although the diffusion processes in social networks have been extensively studied, most existing works aim at maximizing the reach of desirable diffusion processes. We are interested in deploying a group of monitors to detect malicious diffusion processes, such as the spread of computer worms. To capture the impact of model uncertainty, we consider a noisy diffusion model in which the propagation probabilities on each edge could vary within an interval. Our work is built upon recent work in security games; our adversarial setting leads to robust solutions in practice.

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