Global temperature and hydroclimate in warmer climates of the past and future: the Last Interglacial versus greenhouse scenarios

2021 ◽  
Author(s):  
Paolo Scussolini ◽  
Pepijn Bakker ◽  
Paolo De Luca ◽  
Dim Coumou ◽  
Joyce Bosmans ◽  
...  
Keyword(s):  
Time Horizon ◽  
Climate Models ◽  
Last Interglacial ◽  
Recent Period ◽  
The Past ◽  
Temperature And Precipitation ◽  
Hemispheric Temperature ◽  
The Future ◽  
Quantitative Manner ◽  
Climate Studies

<p>Past climates contain precious information about the workings of the climate system, and about what can be expected in a changed climate. The Last Interglacial (LIG; ca. 125,000 years ago) is the most recent period of climate warmer than modern, at least in the Northern Hemisphere. Because of this, it has been often proposed that the LIG holds a partial analogy with a future warmer climate forced by enhanced greenhouse effect. Still, such analogy has never been examined in a quantitative manner. Here we address the question: for which scenario, time horizon, regions and season is the climate of the LIG a useful analogue of the future? We use the results of 13 climate models that performed the standard experiments of PMIP4 and CMIP6, and present a comparison of hemispheric temperature and precipitation between the LIG and SSP scenarios of the future. We also two independent assessments of models performance, by comparing their temperature and precipitation to climate reanalysis of the last decades and to proxies of the LIG. Insights gained from this comparison can inform studies in disciplines beyond climate studies, such as hydrology and ecology.</p>

Fractal-multifractal ensembles of downscaled precipitation and temperature sets as implied by climate models

2021 ◽  
Author(s):  
Mahesh Lal Maskey ◽  
David Joseph Serrano Suarez ◽  
Joshua H. Viers ◽  
Josue Medellin-Azuara ◽  
Bellie Sivakumar ◽  
...  
Keyword(s):  
Climate Models ◽  
Geometric Approach ◽  
Holistic Approach ◽  
Sensitivity Study ◽  
Climatic Data ◽  
Fractal Function ◽  
The Past ◽  
Global Circulation Models ◽  
The Future ◽  
Precipitation And Temperature

<p>Describing the specific details and textures implicit in real-world hydro-climatic data sets is paramount for the proper description and simulation of variables such as precipitation, streamflow, and temperature time series. To this aim, a couple of decades ago, a deterministic geometric approach, the so-called fractal-multifractal (FM) method,<sup>1,2</sup> was introduced. Such is a holistic approach capable of faithfully encoding (describing)<sup>3</sup>, simulating<sup>4</sup>, and downscaling<sup>5</sup> hydrologic records in time, as the outcome of a fractal function illuminated by a multifractal measure. This study employs the FM method to generate ensembles of daily precipitation and temperature sets obtained from global circulation models (GCMs). Specifically, this study uses data obtained via ten GCM models, two sets of daily records, as implied from the past, over a year, and three sets projected for the future, as downscaled via localized constructed analogs (LOCA) for a couple of sites in California. The study demonstrates that faithful representations of all sets may be achieved via the FM approach, using encodings relying on 10 and 8 geometric (FM) parameters for rainfall and temperature, respectively. They result in close approximations of the data's histogram, entropy, and autocorrelation functions. By presenting a sensitivity study of FM parameters' for historical and projected data, this work concludes that the FM representations are useful for tracking and foreseeing the records' complexity<sup>6</sup> in the past and the future and other applications in hydrology such as bias correction.</p><p> </p><p> </p><p><strong>References</strong></p>

scholarly journals Evolution of Rhonegletscher, Switzerland, over the past 125 years and in the future: application of an improved flowline model

2007 ◽  
Vol 46 ◽  
pp. 268-274 ◽  
Author(s):  
Shin Sugiyama ◽  
Andreas Bauder ◽  
Conradin Zahno ◽  
Martin Funk
Keyword(s):  
Mass Balance ◽  
Aerial Photographs ◽  
Future Application ◽  
Equilibrium Line Altitude ◽  
Future Evolution ◽  
The Past ◽  
Temperature And Precipitation ◽  
The Future ◽  
Shape Effects ◽  
Precipitation Records

AbstractTo study the past and future evolution of Rhonegletscher, Switzerland, a flowline model was developed to include valley shape effects more accurately than conventional flowband models. In the model, the ice flux at a gridpoint was computed by a two-dimensional ice-flow model applied to the valley cross-section. The results suggested the underestimation of the accumulation area, which seems to be a general problem of flowline modelling arising from the model’s one-dimensional nature. The corrected mass balance was coupled with the equilibrium-line altitude (ELA) change, which was reconstructed for the period 1878–2003 from temperature and precipitation records, to run the model for the past 125 years. The model satisfactorily reproduced both changes in the terminus position and the total ice volume derived from digital elevation models of the surface obtained by analyses of old maps and aerial photographs. This showed the model’s potential to simulate glacier evolution when an accurate mass balance could be determined. The future evolution of Rhonegletscher was evaluated with three mass-balance conditions: the mean for the period 1994–2003, and the most negative (2003) and positive (1978) mass-balance values for the past 50 years. The model predicted volume changes of –18%, –58% and +38% after 50 years for the three conditions, respectively.

scholarly journals Projected Seasonal Changes in Large-Scale Global Precipitation and Temperature Extremes Based on the CMIP5 Ensemble

2020 ◽  
Vol 33 (13) ◽  
pp. 5651-5671 ◽  
Author(s):  
Wang Zhan ◽  
Xiaogang He ◽  
Justin Sheffield ◽  
Eric F. Wood
Keyword(s):  
Extreme Events ◽  
Large Scale ◽  
Climate Models ◽  
Spatial Scales ◽  
Extreme Temperature ◽  
Economic Losses ◽  
Temperature And Precipitation ◽  
Extreme Precipitation Events ◽  
The Future ◽  
Precipitation Events

AbstractOver the past decades, significant changes in temperature and precipitation have been observed, including changes in the mean and extremes. It is critical to understand the trends in hydroclimatic extremes and how they may change in the future as they pose substantial threats to society through impacts on agricultural production, economic losses, and human casualties. In this study, we analyzed projected changes in the characteristics, including frequency, seasonal timing, and maximum spatial and temporal extent, as well as severity, of extreme temperature and precipitation events, using the severity–area–duration (SAD) method and based on a suite of 37 climate models archived in phase 5 of the Coupled Model Intercomparison Project (CMIP5). Comparison between the CMIP5 model estimated extreme events and an observation-based dataset [Princeton Global Forcing (PGF)] indicates that climate models have moderate success in reproducing historical statistics of extreme events. Results from the twenty-first-century projections suggest that, on top of the rapid warming indicated by a significant increase in mean temperature, there is an overall wetting trend in the Northern Hemisphere with increasing wet extremes and decreasing dry extremes, whereas the Southern Hemisphere will have more intense wet extremes. The timing of extreme precipitation events will change at different spatial scales, with the largest change occurring in southern Asia. The probability of concurrent dry/hot and wet/hot extremes is projected to increase under both RCP4.5 and RCP8.5 scenarios, whereas little change is detected in the probability of concurrent dry/cold events and only a slight decrease of the joint probability of wet/cold extremes is expected in the future.

Future Climate Projection and Zoning of Extreme Temperature Indices

2021 ◽  
Author(s):  
Mohammad Askari Zadeh ◽  
Gholamali Mozaffari ◽  
Mansoureh Kouhi ◽  
Younes Khosravi
Keyword(s):  
Carbon Dioxide Emissions ◽  
Extreme Temperature ◽  
Extreme Weather Events ◽  
Base Period ◽  
The Past ◽  
Temperature And Precipitation ◽  
Weather Events ◽  
The Future ◽  
Temperature Indices ◽  
Future Climate Projection

Abstract Global warming due to increasing carbon dioxide emissions over the past two centuries has had numerous climatic consequences. The change in the behavior and characteristics of extreme weather events such as temperature and precipitation is one of the consequences that have been of interest to researchers worldwide. In this study, the trend of 3 extreme indices of temperature: SU35, TR20, and DTR over two future periods have been studied using downscaled output of 3 GCMs in Razavi Khorasan province, Iran. The results show that the range of temperature diurnal variation (DTR) at three stations of Mashhad, Torbat-e-Heydarieh and Sabzevar during the base period has been reduced significantly. The trend of the number of summer days with temperatures above 35°C (SU35) in both Mashhad and Sabzevar stations was positive and no significant trend was found at Torbat-e-Heydarieh station. The number of tropical nights index (TR20) also showed a positive and significant increase in the three stations under study. The results showed highly significant changes in temperature extremes. The percentage of changes in SU35 index related to base period (1961–2014) for all three models (CNCM3, HadCM3 and NCCCSM) under A1B and A2 scenarios indicated a significant increase for the future periods of 2011–2030 and 2046–2065. TR20 is also expected to increase significantly during the two future periods. The percentage of changes of DTR into the future is negligible.

On the Arrow of Spacetime

2018 ◽  
Author(s):  
Alexandre Harvey-Tremblay
Keyword(s):  
Time Horizon ◽  
Statistical Physics ◽  
Space Time ◽  
Arrow Of Time ◽  
Speed Of Light ◽  
Standard Description ◽  
The Past ◽  
The Future ◽  
Local Space ◽  
Future Events

Consistent with special relativity and statistical physics, here we construct a partition function of space-time events. The union of these two theories resolves longstanding problems in regards to time. It augments the standard description of time given by the (non-relativistic) arrow of time to one able to show the emergence of three macroscopic regimes of time: the past, the present, and the future, represented by space-like entropy, light-like entropy, and time-like entropy, respectively, and in a manner consistent with our experience of said regimes. First, using Fermi-Dirac statistics, we find that the system essentially describes a "waterfall" of space-time events. This "waterfall" recedes in space-time at the speed of light towards the direction of the future as it "floods" local space with events that it depletes from the past. In this union, an observer O will perceive two horizons that can be interpreted as hiding events behind it. The first is an event horizon, and its entropy hides events in the regions that O cannot see. The second is a time horizon, and its entropy "shields" events from O's causal influence. As only past events are "shielded", and not future events, an asymmetry in time is thus created. Finally, future events are hidden by an entropy prohibiting O from knowing the future before the present catches on.

scholarly journals Sea Ice in the Canadian Arctic Archipelago: Modeling the Past (1950–2004) and the Future (2041–60)

2009 ◽  
Vol 22 (8) ◽  
pp. 2181-2198 ◽  
Author(s):  
Tessa Sou ◽  
Gregory Flato
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Global Climate ◽  
Canadian Arctic ◽  
Arctic Sea Ice ◽  
Global Climate Models ◽  
Canadian Arctic Archipelago ◽  
The Past ◽  
The Future ◽  
Ice Retreat

Abstract Considering the recent losses observed in Arctic sea ice and the anticipated future warming due to anthropogenic greenhouse gas emissions, sea ice retreat in the Canadian Arctic Archipelago (CAA) is expected and indeed is already being observed. As most global climate models do not resolve the CAA region, a fine-resolution ice–ocean regional model is developed and used to make a projection of future changes in the CAA sea ice. Results from a historical run (1950–2004) are used to evaluate the model. The model does well in representing observed sea ice spatial and seasonal variability, but tends to underestimate summertime ice cover. The model results for the future (2041–60) show little change in wintertime ice concentrations from the past, but summertime ice concentrations decrease by 45%. The ice thickness is projected to decrease by 17% in the winter and by 36% in summer. Based on this study, a completely ice-free CAA is unlikely by the year 2050, but the simulated ice retreat suggests that the region could support some commercial shipping.

scholarly journals The effect of climate change on habitat suitability and a distribution model of the Iranian fat-tailed gecko, Eublepharis angramainyu Anderson and Leviton, 1966 (Sauria: Eublepharidae) since the Last Interglacial to 2050

2021 ◽  
Author(s):  
Rasoul Karamiani ◽  
Nasrullah Rastegar-Pouyani
Keyword(s):  
Distribution Model ◽  
Valid Species ◽  
Last Interglacial ◽  
The Past ◽  
A Value ◽  
Distribution Ranges ◽  
The Future ◽  
Scenario Model ◽  
Suitable Habitats

Surveying the role of climate changes on the species distributions in the past, present and future, and correlating these with changes in distribution ranges have attracted considerable research interest. The leopard geckos of the genus Eublepharis Gray, 1827 (family Eublepharidae), as a vicariate group, comprises six valid species distributed from Turkey through the Iranian Plateau to India, of which E. angramainyu, E. macularius and E. turcmenicus occur in Iran. In this study, we modelled the potential distribution areas for E. angramainyu and determined the suitable habitats in the past (the last interglacial [LIG] and mid-Holocene [MH]), present (1950–2000), and also predicted four scenarios in the future (2050) by using the maximum entropy approach (MaxEnt). The obtained models indicated very good values of the area under curve (AUC): LIG = 0.996 ± 0.003, MH = 0.996 ± 0.004, contemporary period = 0.995 ± 0.004, and the future = 0.997 ± 0.002. Precipitation of the coldest quarter and precipitation of the warmest quarter were the most important factors shaping the distribution of E. angramainyu. As it seems, climatic changes have been responsible for a southward shift in distribution and suitable habitats of E. angramainyu from the LIG (~150,000–120,000 years ago) to the future. The representative concentration pathway (RCP) 2.6 scenario model of the future predicted a much more restricted distribution and less suitable habitats due to radiation of the forcing level which reaches a value of around 3.1 W/m² by mid-century and returns to 2.6 W/m² by 2100.

scholarly journals Future projections of temperature and precipitation for Antarctica

2021 ◽  
Author(s):  
Kamal Tewari ◽  
Saroj Kanta Mishra ◽  
Popat Salunke ◽  
Anupam Dewan
Keyword(s):  
Climate Models ◽  
Historical Period ◽  
Sea Levels ◽  
Surface Warming ◽  
Temperature Bias ◽  
Temperature And Precipitation ◽  
The Future ◽  
High Emission ◽  
Precipitation Increase ◽  
Better Than

Abstract Antarctica directly impacts the lives of more than half of the world’s population living in the coastal regions. Therefore it is highly desirable to project its climate for the future. But it is a region where the climate models have large inter-modal variability and hence it raises questions about the robustness of the projections available. Therefore, we have examined 87 global models from three modeling consortia (CMIP5, CMIP6, and NEX-GDDP), characterized their fidelity, selected a set of 10 models (MM10) performing satisfactorily, and used them to make the future projection of precipitation and temperature, and assessed the contribution of precipitation towards sea-levels. For the historical period, the multi-model mean (MMM) of CMIP5 performed slightly better than CMIP6 and was worse for NEX-GDDP, with negligible surface temperature bias of approximately 0.5°C and a 17.5% and 19% biases in the mean precipitation noted in both CMIP consortia. These biases considerably reduced in MM10, with 21st century projections showing surface warming of approximately 5.1 - 5.3°C and precipitation increase approximately 44 - 50% against ERA-5 under high-emission scenarios in both CMIP consortia. This projected precipitation increase is much less than that projected using MMM in previous studies with almost the same level of warming, implying approximately 40.0 mm/year contribution of precipitation towards sea-level mitigation against approximately 65.0 mm/year.

scholarly journals Validation of SWAT simulated streamflow in the Eastern Nile and sensitivity to climate change

2011 ◽  
Vol 8 (5) ◽  
pp. 9005-9062 ◽  
Author(s):  
D. T. Mengistu ◽  
A. Sorteberg
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Annual Rainfall ◽  
Annual Streamflow ◽  
Blue Nile ◽  
Temperature And Precipitation ◽  
Monthly Streamflow ◽  
The Future ◽  
Precipitation Changes ◽  
Precipitation And Temperature

Abstract. The hydrological model SWAT was calibrated with daily station based precipitation and temperature data for the whole Eastern Nile basin including the three subbasins: the Blue Nile, Baro Akobo and Tekeze. The daily and monthly streamflow was calibrated and validated at six outlets in the three different subbasins. The model performed very well in simulating the monthly variability of the Eastern Nile streamflow while comparison to daily data revealed a more diverse performance for the extreme events. Of the Eastern Nile average annual rainfall it was estimated that around 60% is lost through evaporation and estimated runoff coefficients were 0.24, 0.30 and 0.18 for Blue Nile, Baro Akobo and Tekeze subbasins, respectively. About half to two-thirds of the runoff could be attributed to surface runoff while the remaining contributions were from groundwater. The annual streamflow sensitivity to changes in precipitation and temperature differed among the basins and the dependence of the response on the strength of the changes was not linear. On average the annual streamflow responses to a change in precipitation with no temperature change was 19%, 17%, and 26% per 10% change in precipitation while the average annual streamflow responses to a change in temperature and no precipitation change was −4.4% K−1, −6.4% K−1, and −1.3% K−1 for Blue Nile, Baro Akobo and Tekeze river basin, respectively. While we show the Eastern Nile to be very sensitive to precipitation changes, using 47 temperature and precipitation scenarios from 19 AOGCMs participating in IPCC AR4 we estimated the future change in streamflow to be strongly dependent on the choice of climate model as the climate models disagree on both the strength and the direction of future precipitation changes. Thus, no clear conclusions can be made about the future changes in Eastern Nile streamflow.

scholarly journals Calendar effects on surface air temperature and precipitation based on model-ensemble equilibrium and transient simulations from PMIP4 and PACMEDY

2021 ◽  
Author(s):  
Xiaoxu Shi ◽  
Martin Werner ◽  
Carolin Krug ◽  
Chris M. Brierley ◽  
Anni Zhao ◽  
...  
Keyword(s):  
Air Temperature ◽  
Seasonal Cycle ◽  
Surface Air Temperature ◽  
Boreal Summer ◽  
Last Interglacial ◽  
Calendar Effects ◽  
Fixed Length ◽  
The Past ◽  
Temperature And Precipitation ◽  
Transient Simulations

Abstract. Numerical modelling enables a comprehensive understanding not only of the Earth's system today, but also of the past. To date, a significant amount of time and effort has been devoted to paleoclimate modeling and analysis, which involves the latest and most advanced Paleoclimate Modelling Intercomparison Project phase 4 (PMIP4). The definition of seasonality, which is influenced by slow variations in the Earth's orbital parameters, plays a key role in determining the calculated seasonal cycle of the climate. In contrast to the classical calendar used today, where the lengths of the months and seasons are fixed, the angular calendar calculates the lengths of the months and seasons according to a fixed number of degrees along the Earth's orbit. When comparing simulation results for different time intervals, it is essential to account for the angular calendar to ensure that the data for comparison is from the same position along the Earth's orbit. Most models use the classical "fixed-length" calendar, which can lead to strong distortions of the monthly and seasonal values, especially for the climate of the past. Here, by analyzing daily outputs from multiple PMIP4 model simulations, we examine calendar effects on surface air temperature and precipitation under mid-Holocene, last interglacial, and pre-industrial climate conditions. We conclude that: (a) The largest cooling bias occurs in autumn when the classical calendar is applied for the mid-Holocene and last interglacial. (b) The sign of the temperature anomalies between the Last Interglacial and pre-industrial in boreal autumn can be reversed after the switch from classical to angular calendar, particularly over the Northern Hemisphere continents. (c) Precipitation over West Africa is overestimated in boreal summer and underestimated in boreal autumn when the "fixed-length" seasonal cycle is applied. (d) Finally, correcting the calendar based on the monthly model results can reduce the biases to a large extent, but not completely eliminate them. In addition, we examine the calendar effects in 3 transient simulations for 6–0 ka by AWI-ESM, MPI-ESM, and IPSL. We find significant discrepancies between adjusted and unadjusted temperature values over ice-free continents for both hemispheres in boreal autumn. While for other seasons the deviations are relatively small. A drying bias can be found in the summer monsoon precipitation in Africa (in the "fixed-length" calendar), whereby the magnitude of bias becomes smaller over time. Overall, our study underlines the importance of the application of calendar transformation in the analysis of climate simulations. Neglecting the calendar effects could lead to a profound artificial distortion of the calculated seasonal cycle of surface air temperature and precipitation. One important fact to be noted here is that the discrepancy in seasonality under different calendars is an analysis bias and is highly depends on the choice of the reference position/date (usually the vernal equinox, which is set to 31th March) on the Earth's ellipse around the sun. Different model groups may apply different reference dates, so ensuring a consistent reference date and seasonal definition is key when we compare results across multiple models.

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