scholarly journals AirClim: an efficient tool for climate evaluation of aircraft technology

2008 ◽  
Vol 8 (16) ◽  
pp. 4621-4639 ◽  
Author(s):  
V. Grewe ◽  
A. Stenke
Keyword(s):  
Climate Change ◽  
Water Vapour ◽  
Radiative Forcing ◽  
Climate Impacts ◽  
Assessment Tools ◽  
Surface Temperature Change ◽  
Near Surface ◽  
Temperature Changes ◽  
Wide Range ◽  
Concentration Changes

Abstract. Climate change is a challenge to society and to cope with requires assessment tools which are suitable to evaluate new technology options with respect to their impact on global climate. Here we present AirClim, a model which comprises a linearisation of atmospheric processes from the emission to radiative forcing, resulting in an estimate in near surface temperature change, which is presumed to be a reasonable indicator for climate change. The model is designed to be applicable to aircraft technology, i.e. the climate agents CO2, H2O, CH4 and O3 (latter two resulting from NOx-emissions) and contrails are taken into account. AirClim combines a number of precalculated atmospheric data with aircraft emission data to obtain the temporal evolution of atmospheric concentration changes, radiative forcing and temperature changes. These precalculated data are derived from 25 steady-state simulations for the year 2050 with the climate-chemistry model E39/C, prescribing normalised emissions of nitrogen oxides and water vapour at various atmospheric regions. The results show that strongest climate impacts (year 2100) from ozone changes occur for emissions in the tropical upper troposphere (60 mW/m2; 80 mK for 1 TgN/year emitted) and from methane changes from emissions in the middle tropical troposphere (−2.7% change in methane lifetime; –30 mK per TgN/year). For short-lived species (e.g. ozone, water vapour, methane) individual perturbation lifetimes are derived depending on the region of emission. A comparison of this linearisation approach with results from a comprehensive climate-chemistry model shows reasonable agreement with respect to concentration changes, radiative forcing, and temperature changes. For example, the total impact of a supersonic fleet on radiative forcing (mainly water vapour) is reproduced within 10%. A wide range of application is demonstrated.

scholarly journals A strategy for climate evaluation of aircraft technology: an efficient climate impact assessment tool – AirClim

2007 ◽  
Vol 7 (4) ◽  
pp. 12185-12229 ◽  
Author(s):  
V. Grewe ◽  
A. Stenke
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
Climate Impact ◽  
Climate Impacts ◽  
Assessment Tools ◽  
Nox Emissions ◽  
Near Surface ◽  
Temperature Changes ◽  
Concentration Changes ◽  
The Impact

Abstract. Climate change is a challenge to society and to cope with requires assessment tools which are suitable to evaluate new technology options with respect to their impact on climate. Here we present AirClim, a model which comprises a linearisation of the processes occurring from the emission to an estimate in near surface temperature change, which is presumed to be a reasonable indicator for climate change. The model is designed to be applicable to aircraft technology, i.e.~the climate agents CO2, H2O, CH4 and O3 (latter two resulting from NOx-emissions) and contrails are taken into account. It employs a number of precalculated atmospheric data and combines them with aircraft emission data to obtain the temporal evolution of atmospheric concentration changes, radiative forcing and temperature changes. The linearisation is based on precalculated data derived from 25 steady-state simulations of the state-of-the-art climate-chemistry model E39/C, which include sustained normalised emissions at various atmospheric regions. The results show that strongest climate impacts from ozone changes occur for emissions in the tropical upper troposphere (60 mW/m²; 80 mK for 1 TgN emitted), whereas from methane in the middle tropical troposphere (–2.7% change in methane lifetime; –30 mK per TgN). The estimate of the temperature changes caused by the individual climate agents takes into account a perturbation lifetime, related to the region of emission. A comparison of this approach with results from the TRADEOFF and SCENIC projects shows reasonable agreement with respect to concentration changes, radiative forcing, and temperature changes. The total impact of a supersonic fleet on radiative forcing (mainly water vapour) is reproduced within 5%. For subsonic air traffic (sustained emissions after 2050) results show that although ozone-radiative forcing is much less important than that from CO2 for the year 2100. However the impact on temperature is of comparable size even when taking into account temperature decreases from CH4. That implies that all future measures for climate stabilisation should concentrate on both CO2 and NOx emissions. A direct comparison of super- with subsonic aircraft (250 passengers, 5400 nm) reveals a 5 times higher climate impact of supersonics.

scholarly journals Incorrect Asian aerosols affecting the attribution and projection of regional climate change in CMIP6 models

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Zhili Wang ◽  
Lei Lin ◽  
Yangyang Xu ◽  
Huizheng Che ◽  
Xiaoye Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
Impact Analysis ◽  
Climate Model ◽  
Regional Climate ◽  
Eastern China ◽  
Coupled Model ◽  
Regional Climate Change ◽  
Anthropogenic Aerosol ◽  
Wide Range

AbstractAnthropogenic aerosol (AA) forcing has been shown as a critical driver of climate change over Asia since the mid-20th century. Here we show that almost all Coupled Model Intercomparison Project Phase 6 (CMIP6) models fail to capture the observed dipole pattern of aerosol optical depth (AOD) trends over Asia during 2006–2014, last decade of CMIP6 historical simulation, due to an opposite trend over eastern China compared with observations. The incorrect AOD trend over China is attributed to problematic AA emissions adopted by CMIP6. There are obvious differences in simulated regional aerosol radiative forcing and temperature responses over Asia when using two different emissions inventories (one adopted by CMIP6; the other from Peking university, a more trustworthy inventory) to driving a global aerosol-climate model separately. We further show that some widely adopted CMIP6 pathways (after 2015) also significantly underestimate the more recent decline in AA emissions over China. These flaws may bring about errors to the CMIP6-based regional climate attribution over Asia for the last two decades and projection for the next few decades, previously anticipated to inform a wide range of impact analysis.

scholarly journals Atmospheric Dynamics Feedback: Concept, Simulations, and Climate Implications

2018 ◽  
Vol 31 (8) ◽  
pp. 3249-3264 ◽  
Author(s):  
Michael P. Byrne ◽  
Tapio Schneider
Keyword(s):  
Climate Change ◽  
Atmospheric Circulation ◽  
Radiative Forcing ◽  
Large Scale ◽  
Climate Models ◽  
Atmospheric Dynamics ◽  
Future Climate Change ◽  
Coupled Models ◽  
Near Surface ◽  
Circulation Changes

AbstractThe regional climate response to radiative forcing is largely controlled by changes in the atmospheric circulation. It has been suggested that global climate sensitivity also depends on the circulation response, an effect called the “atmospheric dynamics feedback.” Using a technique to isolate the influence of changes in atmospheric circulation on top-of-the-atmosphere radiation, the authors calculate the atmospheric dynamics feedback in coupled climate models. Large-scale circulation changes contribute substantially to all-sky and cloud feedbacks in the tropics but are relatively less important at higher latitudes. Globally averaged, the atmospheric dynamics feedback is positive and amplifies the near-surface temperature response to climate change by an average of 8% in simulations with coupled models. A constraint related to the atmospheric mass budget results in the dynamics feedback being small on large scales relative to feedbacks associated with thermodynamic processes. Idealized-forcing simulations suggest that circulation changes at high latitudes are potentially more effective at influencing global temperature than circulation changes at low latitudes, and the implications for past and future climate change are discussed.

Climate, Oceans, and the Law of Special and General Adaptation

2016 ◽  
Author(s):  
U. Rashid Sumaila
Keyword(s):  
Climate Change ◽  
Climate Change Impacts ◽  
Climate Impacts ◽  
Adaptive Responses ◽  
Wide Range ◽  
General Adaptation ◽  
The Law ◽  
Adaptation Law ◽  
Private Actors ◽  
International Fisheries

This chapter describes the literature of adaptation law in the context of international ocean governance. Adaptation law consists of rules aimed at minimizing the social costs associated with human response to climate impacts. These can be used to shape the behaviour of private actors or public institutions. The law sometimes might provide incentives to make enterprises more resilient as it makes capital unnecessarily stranded during climate change. In order to illustrate the challenges of implementation in the ocean context, the chapter focuses on two examples: international fisheries and ‘mari-engineering’. International fisheries represent ongoing ocean use and regulated by a well-developed body of international law. Due to the wide range of possible climate impacts and adaptive responses, proactive changes to existing fisheries rules in anticipation of climate change fit into the category of general adaptation law, while mari-engineering is engineering the seas to slow or halt climate change impacts.

scholarly journals Assessing the Climate Impact of Formation Flights

Aerospace ◽  
2020 ◽  
Vol 7 (12) ◽  
pp. 172 ◽  
Author(s):  
Katrin Dahlmann ◽  
Sigrun Matthes ◽  
Hiroshi Yamashita ◽  
Simon Unterstrasser ◽  
Volker Grewe ◽  
...  
Keyword(s):  
Climate Impact ◽  
Climate Impacts ◽  
Response Model ◽  
Climate Response ◽  
Surface Temperature Change ◽  
Near Surface ◽  
Average Decrease ◽  
Co2 Effects ◽  
Saturation Effects ◽  
The Impact

An operational measure that is inspired by migrant birds aiming toward the mitigation of aviation climate impact is to fly in aerodynamic formation. When this operational measure is adapted to commercial aircraft it saves fuel and is, therefore, expected to reduce the climate impact of aviation. Besides the total emission amount, this mitigation option also changes the location of emissions, impacting the non-CO2 climate effects arising from NOx and H2O emissions and contrails. Here, we assess these non-CO2 climate impacts with a climate response model to assure a benefit for climate not only due to CO2 emission reductions, but also due to reduced non-CO2 effects. Therefore, the climate response model AirClim is used, which includes CO2 effects and also the impact of water vapor and contrail induced cloudiness as well as the impact of nitrogen dioxide emissions on the ozone and methane concentration. For this purpose, AirClim has been adopted to account for saturation effects occurring for formation flight. The results of the case studies show that the implementation of formation flights in the 50 most popular airports for the year 2017 display an average decrease of fuel consumption by 5%. The climate impact, in terms of average near surface temperature change, is estimated to be reduced in average by 24%, with values of individual formations between 13% and 33%.

Artificial acceleration of the Brewer-Dobson circulation due to stratospheric cooling

2020 ◽  
Author(s):  
Roland Eichinger ◽  
Petr Sacha
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
Climate Model ◽  
Ghg Emissions ◽  
Scale Height ◽  
Temperature Changes ◽  
Stratospheric Dynamics ◽  
Upward Velocity ◽  
Stratospheric Cooling ◽  
Unit Conversion

<p>There is robust observational evidence that the troposphere is warming and the stratosphere is cooling in response to the radiative forcing of anthropogenic greenhouse gas (GHG) emissions. Temperature changes directly influence the vertical structure of the atmopshere. Numerous studies have analysed the thermal expansion of the troposphere, in particular the tropopause rise and its interaction with the Brewer-Dobson circulation (BDC). Stratospheric cooling, however, reduces the upward shift of pressure levels with increasing altitude so that it reverses sign at some height, leading to a downward shift of the middle to upper stratosphere. This "stratospheric shrinkage“ effect is a strong and robust feature of climate change and it is well documented through observations. Still, literature on this effect is relatively sparse and its impact on stratospheric dynamics is generally neglected.</p><p>In this study, we report and quantify the uncertainty in residual upward velocity (w*) trends that arises from the implicit neglection of stratospheric shrinkage in the data model request for the Chemistry-Climate Model Initiative part 1 (CCMI-1). Tropical w* is often taken as a proxy for diagnosing the BDC strength. In the data request, a constant scale height is assumed for conversion of w* from Pa/s to m/s . However, the scale height significantly decreases over time in the climate simulations as a result of stratospheric shrinkage.</p><p>We show that stratospheric cooling enhances the w* trends if the unit conversion is made with constant scale height, which can be misinterpreted as BDC acceleration. We quantify this effect to account for around 20% of the w* trend across the 21st century, consistently among the CCMI-1 climate projection simulations. Past studies that based w* trend analyses on these data therefore made a 20% error. Moreover, we call attention that other dynamical diagnostics are affected by the neglection of stratospheric shrinkage too and also the data requests of other multi-model assessments use the constant scale height assumtion for unit conversion in climate change simulations.</p>

Water vapour in the Upper Troposphere and Lower Stratosphere (UTLS): A new vertically resolved dataset from limb and nadir satellite observations

2020 ◽  
Author(s):  
Hao Ye ◽  
Michaela Hegglin ◽  
Martina Krämer ◽  
Christian Rolf ◽  
Alexandra Laeng ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Vapour ◽  
Radiative Forcing ◽  
Lower Stratosphere ◽  
Climate Model ◽  
Chemical Properties ◽  
Upper Troposphere ◽  
Data Record ◽  
Tropopause Region ◽  
Quality Water

<p>Water vapour in the upper troposphere and lower stratosphere (UTLS) has a significant impact both on the radiative and chemical properties of the atmosphere. Reliable water vapour observations are essential for the evaluation of the accuracy of UTLS water vapour from model simulations, and thereafter of the contribution to the global radiative forcing and climate change. Limb-viewing and nadir satellites provide high quality water vapour observations above the lower stratosphere and below the upper troposphere, respectively, but show large uncertainties in the tropopause region.<span>  </span>Within the ESA Water Vapour Climate Change Initiative, we have developed a new scheme to optimally estimate water vapour profiles in the UTLS and in particular across the tropopause, by merging observations from a set of limb and nadir satellites from 2010 to 2014. The new data record of vertically resolved water vapour is validated against the aircraft in-situ water vapour observations from the JULIA database and frostpoint hydrometer records from WAVAS. Furthermore, the new data record is used to evaluate the UTLS water vapour distribution and interannual variations from chemistry-climate model (CCM) simulations and the ERA-5 reanalysis.</p>

scholarly journals Climate change damages to Alaska public infrastructure and the economics of proactive adaptation

2016 ◽  
Vol 114 (2) ◽  
pp. E122-E131 ◽  
Author(s):  
April M. Melvin ◽  
Peter Larsen ◽  
Brent Boehlert ◽  
James E. Neumann ◽  
Paul Chinowsky ◽  
...  
Keyword(s):  
Climate Change ◽  
Coastal Erosion ◽  
Economic Impacts ◽  
Climate Impacts ◽  
Public Infrastructure ◽  
Adaptation Measures ◽  
Near Surface ◽  
Permafrost Thaw ◽  
Northern Latitudes ◽  
Southcentral Alaska

Climate change in the circumpolar region is causing dramatic environmental change that is increasing the vulnerability of infrastructure. We quantified the economic impacts of climate change on Alaska public infrastructure under relatively high and low climate forcing scenarios [representative concentration pathway 8.5 (RCP8.5) and RCP4.5] using an infrastructure model modified to account for unique climate impacts at northern latitudes, including near-surface permafrost thaw. Additionally, we evaluated how proactive adaptation influenced economic impacts on select infrastructure types and developed first-order estimates of potential land losses associated with coastal erosion and lengthening of the coastal ice-free season for 12 communities. Cumulative estimated expenses from climate-related damage to infrastructure without adaptation measures (hereafter damages) from 2015 to 2099 totaled $5.5 billion (2015 dollars, 3% discount) for RCP8.5 and $4.2 billion for RCP4.5, suggesting that reducing greenhouse gas emissions could lessen damages by $1.3 billion this century. The distribution of damages varied across the state, with the largest damages projected for the interior and southcentral Alaska. The largest source of damages was road flooding caused by increased precipitation followed by damages to buildings associated with near-surface permafrost thaw. Smaller damages were observed for airports, railroads, and pipelines. Proactive adaptation reduced total projected cumulative expenditures to $2.9 billion for RCP8.5 and $2.3 billion for RCP4.5. For road flooding, adaptation provided an annual savings of 80–100% across four study eras. For nearly all infrastructure types and time periods evaluated, damages and adaptation costs were larger for RCP8.5 than RCP4.5. Estimated coastal erosion losses were also larger for RCP8.5.

scholarly journals The Climate Impact of COVID19 Induced Contrail Changes

2021 ◽  
Author(s):  
Andrew Gettelman ◽  
Chieh-Chieh Chen ◽  
Charles G. Bardeen
Keyword(s):  
Surface Temperature ◽  
Land Surface ◽  
Radiative Forcing ◽  
Climate Impact ◽  
Climate Impacts ◽  
Infrared Heating ◽  
Boreal Summer ◽  
Surface Temperature Change ◽  
Effective Radiative Forcing ◽  
Standard Deviations

Abstract. The COVID19 pandemic caused significant economic disruption in 2020 and severely impacted air traffic. We use a state of the art Earth System Model and ensembles of tightly constrained simulations to evaluate the effect of the reductions in aviation traffic on contrail radiative forcing and climate in 2020. In the absence of any COVID19 pandemic caused reductions, the model simulates a contrail Effective Radiative Forcing (ERF) 62 ± 59 m Wm−2 (2 standard deviations). The contrail ERF has complex spatial and seasonal patterns that combine the offsetting effect of shortwave (solar) cooling and longwave (infrared) heating from contrails and contrail cirrus. Cooling is larger in June–August due to the preponderance of aviation in the N. Hemisphere, while warming occurs throughout the year. The spatial and seasonal forcing variations also map onto surface temperature variations. The net land surface temperature change due to contrails in a normal year is estimated at 0.13 ± 0.04 K (2 standard deviations) with some regions warming as much as 0.7 K. The effect of COVID19 reductions in flight traffic decreased contrails. The unique timing of such reductions, which were maximum in N. Hemisphere spring and summer when the largest contrail cooling occurs, means that cooling due to fewer contrails in boreal spring and fall was offset by warming due to fewer contrails in boreal summer to give no significant annual averaged ERF from contrail changes in 2020. Despite no net significant global ERF, because of the spatial and seasonal timing of contrail ERF, some land regions that would have cooled slightly (minimum −0.2 K) but significantly from contrail changes in 2020. The implications for future climate impacts of contrails are discussed.

scholarly journals Climate Change Impacts on Groundwater Recharge in Cold and Humid Climates: Controlling Processes and Thresholds

Climate ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Emmanuel Dubois ◽  
Marie Larocque ◽  
Sylvain Gagné ◽  
Marco Braun
Keyword(s):  
Climate Change ◽  
Groundwater Recharge ◽  
Water Resource Management ◽  
Global Climate Models ◽  
Future Climate Change ◽  
Temperature Changes ◽  
Wide Range ◽  
Long Term Changes ◽  
Precipitation And Temperature

Long-term changes in precipitation and temperature indirectly impact aquifers through groundwater recharge (GWR). Although estimates of future GWR are needed for water resource management, they are uncertain in cold and humid climates due to the wide range in possible future climatic conditions. This work aims to (1) simulate the impacts of climate change on regional GWR for a cold and humid climate and (2) identify precipitation and temperature changes leading to significant long-term changes in GWR. Spatially distributed GWR is simulated in a case study for the southern Province of Quebec (Canada, 36,000 km2) using a water budget model. Climate scenarios from global climate models indicate warming temperatures and wetter conditions (RCP4.5 and RCP8.5; 1951–2100). The results show that annual precipitation increases of >+150 mm/yr or winter precipitation increases of >+25 mm will lead to significantly higher GWR. GWR is expected to decrease if the precipitation changes are lower than these thresholds. Significant GWR changes are produced only when the temperature change exceeds +2 °C. Temperature changes of >+4.5 °C limit the GWR increase to +30 mm/yr. This work provides useful insights into the regional assessment of future GWR in cold and humid climates, thus helping in planning decisions as climate change unfolds. The results are expected to be comparable to those in other regions with similar climates in post-glacial geological environments and future climate change conditions.

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