scholarly journals The impact of a future solar minimum on climate change projections in the Northern Hemisphere

2016 ◽  
Vol 11 (3) ◽  
pp. 034015 ◽  
Author(s):  
G Chiodo ◽  
R García-Herrera ◽  
N Calvo ◽  
J M Vaquero ◽  
J A Añel ◽  
...  
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Solar Minimum ◽  
Climate Change Projections ◽  
The Impact

scholarly journals Compensation between Resolved Wave Driving and Parameterized Orographic Gravity Wave Driving of the Brewer–Dobson Circulation and Its Response to Climate Change

2014 ◽  
Vol 27 (14) ◽  
pp. 5601-5610 ◽  
Author(s):  
Michael Sigmond ◽  
Theodore G. Shepherd
Keyword(s):  
Climate Change ◽  
Gravity Wave ◽  
Northern Hemisphere ◽  
Rossby Wave ◽  
Climate Model ◽  
Wave Drag ◽  
High Latitudes ◽  
Remarkable Degree ◽  
The Impact

Abstract Following recent findings, the interaction between resolved (Rossby) wave drag and parameterized orographic gravity wave drag (OGWD) is investigated, in terms of their driving of the Brewer–Dobson circulation (BDC), in a comprehensive climate model. To this end, the parameter that effectively determines the strength of OGWD in present-day and doubled CO2 simulations is varied. The authors focus on the Northern Hemisphere during winter when the largest response of the BDC to climate change is predicted to occur. It is found that increases in OGWD are to a remarkable degree compensated by a reduction in midlatitude resolved wave drag, thereby reducing the impact of changes in OGWD on the BDC. This compensation is also found for the response to climate change: changes in the OGWD contribution to the BDC response to climate change are compensated by opposite changes in the resolved wave drag contribution to the BDC response to climate change, thereby reducing the impact of changes in OGWD on the BDC response to climate change. By contrast, compensation does not occur at northern high latitudes, where resolved wave driving and the associated downwelling increase with increasing OGWD, both for the present-day climate and the response to climate change. These findings raise confidence in the credibility of climate model projections of the strengthened BDC.

scholarly journals Impact of climate change on hydropower production in the Upper Danube

2021 ◽  
Author(s):  
Ignacio Martin Santos ◽  
Mathew Herrnegger ◽  
Hubert Holzmann
Keyword(s):  
Climate Change ◽  
Spatial Resolution ◽  
Transfer Functions ◽  
Danube River ◽  
Emission Scenarios ◽  
Hydropower Generation ◽  
Climate Change Projections ◽  
Impact Of Climate Change ◽  
The Future ◽  
The Impact

<p>In the last two decades, different climate downscaling initiatives provided climate scenarios for Europe. The most recent initiative, CORDEX, provides Regional Climate Model (RCM) data for Europe with a spatial resolution of 12.5 km, while the previous initiative, ENSEMBLES, had a spatial resolution of 25 km. They are based on different emission scenarios, Representative Concentration Pathways (RCPs) and Special Report on Emission Scenarios (SRES) respectively.</p><p>A study carried out by Stanzel et al. (2018) explored the hydrological impact and discharge projections for the Danube basin upstream of Vienna when using either CORDEX and ENSEMBLES data. This basin covers an area of 101.810<sup></sup>km<sup>2</sup> with a mean annual discharge of 1923 m<sup>3</sup>/s at the basin outlet. The basin is dominated by the Alps, large gradients and is characterized by high annual precipitations sums which provides valuable water resources available along the basin. Hydropower therefore plays an important role and accounts for more than half of the installed power generating capacity for this area. The estimation of hydropower generation under climate change is an important task for planning the future electricity supply, also considering the on-going EU efforts and the “Green Deal” initiative.</p><p>Taking as input the results from Stanzel et al. (2018), we use transfer functions derived from historical discharge and hydropower generation data, to estimate potential changes for the future. The impact of climate change projections of ENSEMBLE and CORDEX in respect to hydropower generation for each basin within the study area is determined. In addition, an assessment of the impact on basins dominated by runoff river plants versus basins dominated by storage plants is considered.</p><p>The good correlation between discharge and hydropower generation found in the historical data suggests that discharge projection characteristics directly affect the future expected hydropower generation. Large uncertainties exist and stem from the ensembles of climate runs, but also from the potential operation modes of the (storage) hydropower plants in the future.</p><p> </p><p> </p><p>References:</p><p>Stanzel, P., Kling, H., 2018. From ENSEMBLES to CORDEX: Evolving climate change projections for Upper Danube River flow. J. Hydrol. 563, 987–999. https://doi.org/10.1016/j.jhydrol.2018.06.057</p><p> </p>

Is Institutional Democracy a Good Proxy for Model Independence?

2016 ◽  
Vol 29 (23) ◽  
pp. 8301-8316 ◽  
Author(s):  
Martin Leduc ◽  
René Laprise ◽  
Ramón de Elía ◽  
Leo Šeparović
Keyword(s):  
Climate Change ◽  
Model Comparison ◽  
Climate Models ◽  
Regional Climate ◽  
Burden Of Proof ◽  
Climate Projections ◽  
Climate Change Projections ◽  
Cross Model ◽  
Structural Differences ◽  
The Impact

Abstract Climate models developed within a given research group or institution are prone to share structural similarities, which may induce resembling features in their simulations of the earth’s climate. This assertion, known as the “same-center hypothesis,” is investigated here using a subsample of CMIP3 climate projections constructed by retaining only the models originating from institutions that provided more than one model (or model version). The contributions of individual modeling centers to this ensemble are first presented in terms of climate change projections. A metric for climate change disagreement is then defined to analyze the impact of typical structural differences (such as resolution, parameterizations, or even entire atmosphere and ocean components) on regional climate projections. This metric is compared to a present climate performance metric (correlation of error patterns) within a cross-model comparison framework in terms of their abilities to identify the same-center models. Overall, structural differences between the pairs of same-center models have a stronger impact on climate change projections than on how models reproduce the observed climate. The same-center criterion is used to detect agreements that might be attributable to model similarities and thus that should not be interpreted as implying greater confidence in a given result. It is proposed that such noninformative agreements should be discarded from the ensemble, unless evidence shows that these models can be assumed to be independent. Since this burden of proof is not generally met by the centers participating in a multimodel ensemble, the authors propose an ensemble-weighting scheme based on the assumption of institutional democracy to prevent overconfidence in climate change projections.

scholarly journals Monitoring the Responses of Deciduous Forest Phenology to 2000–2018 Climatic Anomalies in the Northern Hemisphere

2021 ◽  
Vol 13 (14) ◽  
pp. 2806
Author(s):  
Kevin Bórnez ◽  
Aleixandre Verger ◽  
Adrià Descals ◽  
Josep Peñuelas
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Deciduous Forest ◽  
Regional Scale ◽  
The United States ◽  
Deciduous Forests ◽  
Area Index ◽  
Temperature And Precipitation ◽  
Phenological Metrics ◽  
The Impact

Monitoring the phenological responses of deciduous forests to climate is important, due to the increasing frequency and intensity of extreme climatic events associated with climate change and global warming, which will in turn affect vegetation seasonality. We investigated the spatiotemporal patterns of the response of deciduous forests to climatic anomalies in the Northern Hemisphere, using satellite-derived phenological metrics from the Copernicus Global Land Service Leaf Area Index, and multisource climatic datasets for 2000–2018 at resolutions of 0.1°. Thereafter, we assessed the impact of extreme heatwaves and droughts on this deciduous forest phenology. We assumed that changes in the deciduous forest phenology in the Northern Hemisphere for the period 2000–2018 were monotonic, and that temperature and precipitation were the main climatic drivers. Analyses of partial correlations of phenological metrics with the timing of the start of the season (SoS), end of the season (EoS), and climatic variables indicated that changes in preseason temperature played a stronger role than precipitation in affecting the interannual variability of SoS anomalies: the higher the temperature, the earlier the SoS in most deciduous forests in the Northern Hemisphere (mean correlation coefficient of –0.31). Correlations between the SoS and temperature were significantly negative in 57% of the forests, and significantly positive in 15% of the forests (P < 0.05). Both temperature and precipitation contributed to the advance and delay of the EoS. A later EoS was significantly correlated with a positive Standardized Precipitation Evapotranspiration Index (SPEI) at the regional scale (~30% of deciduous forests). The timings of the EoS and SoS shifted by > 20 d in response to heatwaves throughout most of Europe in 2003, and in the United States of America in 2012. This study contributes to improve our understanding of the phenological responses of deciduous forests in the Northern Hemisphere to climate change and extreme climate events.

Balanced subsampling of future regional climate ensembles of opportunity

2020 ◽  
Author(s):  
Jesús Fernández ◽  
María Dolores Frías
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Regional Climate ◽  
National Level ◽  
Future Climate Change ◽  
Climate Projections ◽  
Climate Modelling ◽  
Model Intercomparison ◽  
Climate Change Projections ◽  
The Impact

&lt;p&gt;International model intercomparison initiatives, such as CORDEX or CMIP5, along with several relatively recent projects at international and national level, provide a wealth of model simulations of future regional climate. In a recent work, Fernandez et al (2019) collected 196 different future climate change projections over Spain, considering data from ENSEMBLES, ESCENA, EURO- and Med-CORDEX, along with their driving global climate projections from CMIP3 and CMIP5. This ensemble mixed different multi-model initiatives in an ensemble of opportunity, in the sense that it does not respond to any scientific design beyond the exploration of multi-model uncertainty. This ensemble of opportunity is not only the result of the mixture of different initiatives, but also responds to the lack of a balanced experimental design within most of the initiatives. Many of the initiatives -especially those unfunded, such as CORDEX- are carried out on a voluntary basis, with no strong constraint in the global climate models (GCMs) used as boundary conditions or in the number of contributing members per regional climate model (RCM).&lt;/p&gt;&lt;p&gt;Fernandez et al (2019) found in this ensemble a strong influence of the driving GCM on the regional climate change signal, along with favored GCMs, selected by many regional climate modelling groups to the detriment of GCMs publishing their output later or not at all. In this work, we quantitatively assess the impact of unbalanced GCM-RCM ensembles. For this purpose, we subsampled the ensemble of opportunity to obtain balanced sets of members according to different &amp;#8220;what-if&amp;#8221; situations: What if all RCMs had contributed a single member to the ensemble? What if each GCM had been dynamically downscaled only once? What if a given GCM/RCM had not contributed to the ensemble? For each hypothesis, there are a number of alternative sub-ensembles, which are used to evaluate uncertainty.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgement:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;This work is partially funded by the Spanish government through MINECO/FEDER co-funded projects INSIGNIA (CGL2016-79210-R) and MULTI-SDM (CGL2015-66583-R).&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Fern&amp;#225;ndez, J., et al. (2019) Consistency of climate change projections from multiple global and regional model intercomparison projects. Clim Dyn 52:1139. https://doi.org/10.1007/s00382-018-4181-8&lt;/p&gt;

The application of probabilistic climate change projections: a comparison of methods of handling uncertainty applied to UK irrigation reservoir design

2014 ◽  
Vol 5 (4) ◽  
pp. 652-666 ◽  
Author(s):  
Michael Green ◽  
Edward Keith Weatherhead
Keyword(s):  
Climate Change ◽  
Probability Distributions ◽  
Latin Hypercube Sampling ◽  
Probabilistic Methods ◽  
Climate Projections ◽  
Climate Change Projections ◽  
Irrigation Reservoir ◽  
Inadequate Sample Size ◽  
Reservoir Design ◽  
The Impact

Climate projections are increasingly being presented in terms of uncertainties and probability distributions rather than median or ‘most-likely’ values. The current national UK climate change projections, UKCP09, provide 10,000 probabilistic projections (PP) and 11 spatially coherent projections (11SCP) for three future emission scenarios. In contrast, previous iterations such as UKCIP02 provided only a single ‘most-likely’ (deterministic) projection for each. This move from deterministic to probabilistic methods of communicating climate change information, whilst increasing the wealth of the data, complicates the process of adaptation planning by communicating extra uncertainty to the public and decision-makers. This paper examines the application of probabilistic climate change projections and explores the impact of uncertainty on decision-making, using a case study of irrigation reservoir design at three sites in the UK. The implications of sub-sampling the PP using both simple random and Latin-hypercube sampling are also explored. The study found that the choice of dataset has a much larger impact on irrigation reservoir design than emission uncertainty. The study confirmed the dangers of inadequate sample size, particularly when applying decision criteria based on extreme events, and found that more advanced stratified sampling techniques did not noticeably improve the reproducibility of decision outcomes.

scholarly journals Present and future impact of aircraft, road traffic and shipping emissions on global tropospheric ozone

2010 ◽  
Vol 10 (23) ◽  
pp. 11681-11705 ◽  
Author(s):  
B. Koffi ◽  
S. Szopa ◽  
A. Cozic ◽  
D. Hauglustaine ◽  
P. van Velthoven
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Tropospheric Ozone ◽  
Road Traffic ◽  
Lower Troposphere ◽  
Mitigation Scenario ◽  
Tropical Zone ◽  
Upper Troposphere ◽  
Transport Emissions ◽  
The Impact

Abstract. In this study, the LMDz-INCA climate-chemistry model and up-to-date global emission inventories are used to investigate the "present" (2000) and future (2050) impacts of transport emissions (road traffic, shipping and aircraft) on global tropospheric ozone. For the first time, both impacts of emissions and climate changes on transport-induced ozone are investigated. The 2000 transport emissions are shown to mainly affect ozone in the Northern Hemisphere, with a maximum increase of the tropospheric column of up to 5 DU, from the South-eastern US to Central Europe. The impact is dominated by road traffic in the middle and upper troposphere, North of 40° S, and by shipping in the northern lower troposphere, over oceanic regions. A strong reduction of road emissions and a moderate (B1 scenario) to high (A1B scenario) increase of the ship and aircraft emissions are projected by the year 2050. As a consequence, LMDz-INCA simulations predict a drastic decrease in the impact of road emissions, whereas aviation would become the major transport perturbation on tropospheric ozone, even in the case of a very optimistic aircraft mitigation scenario. The A1B emission scenario leads to an increase of the impact of transport on zonal mean ozone concentrations in 2050 by up to +30% and +50%, in the Northern and Southern Hemispheres, respectively. Despite a similar total amount of global NOx emissions by the various transport sectors compared to 2000, the overall impact on the tropospheric ozone column is increased everywhere in 2050, due to a sectoral shift in the emissions of the respective transport modes. On the opposite, the B1 mitigation scenario leads to a significant reduction (by roughly 50%) of the ozone perturbation throughout the troposphere compared to 2000. Considering climate change, and according to scenario A1B, a decrease of the O3 tropospheric burden is simulated by 2050 due to climate change (−1.2%), whereas an increase of ozone of up to 2% is calculated in the upper troposphere in the inter-tropical zone, due to enhanced lightning activity. A global impact of similar magnitude is simulated for the transport-induced ozone burden perturbation (−1.6%). As a result, the future increase in global ozone due to changes in anthropogenic emissions is lowered by 12% and by 4%, for the background and the transport-induced ozone, respectively. However, positive and negative climate effects are obtained on ozone, depending on the season, region and altitude, with an increase of the transport-induced ozone perturbation (+0.4 DU) in the already most affected area of Northern Hemisphere.

The key role of ocean-induced non-conservative processes in Northern Hemisphere stratospheric response to climate changes.

2021 ◽  
Author(s):  
Nour-Eddine Omrani ◽  
Noel Keenlyside ◽  
Sandro Lubis ◽  
Fumiaki Ogawa
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Potential Vorticity ◽  
Atmospheric Model ◽  
Finite Amplitude ◽  
Flux Divergence ◽  
Tropical Ocean ◽  
Wave Induced ◽  
The Impact

&lt;p&gt;The response of the Northern Hemisphere (NH) stratosphere to climate change has been usually studied within the classical Transformed Eulerian Mean framework, which focuses mainly on the impact of the resolved atmospheric waves. The role of the non-conservative (or wave-free) processes (like diabatic heating and diffusive potential vorticity mixing) in setting the stratospheric response to climate change remains poorly understood.&amp;#160;Here we use different stand-alone atmospheric model experiments and the newly developed Finite Amplitude Local Wave Activity (FALWA) theory, in order to understand the role and the origins of the non-conservative processes in the NH stratospheric response to climate change.&lt;/p&gt;&lt;p&gt;Our model response can reproduce the well-known weakening of the NH polar stratospheric vortex and strengthening of mid-latitude and subtropical stratospheric westerlies. &amp;#160;It is shown that the overall structure of the wintertime response of the NH stratosphere to climate change is maintained mainly by the ocean-induced non-conservative processes with limited contribution of the wave-induced conservative dynamics. In particular, the tropical ocean warming due to climate change maintains the wave free component of the westerly wind, which setup the background wind for poleward wave propagation and the associated wave-induced weakening of the polar stratospheric vortex. The FALWA budget reveals that the weak response of the conservative (or wave induced) component of the stratospheric westerly is maintained mainly by the eddy meridional potential vorticity (PV) transport (or EP-flux divergence) against the non-conservative diffusive PV-mixing. Our work requires the consideration of the non-conservative processes for an accurate dynamical understanding of the stratospheric response to climate change.&lt;/p&gt;

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