Temperature projections over Iran during the twenty-first century using CMIP5 models

2021 ◽  
Author(s):  
David Francisco Bustos Usta ◽  
Maryam Teymouri ◽  
Uday Chatterjee ◽  
Bappaditya Koley
Keyword(s):  
First Century ◽  
Cmip5 Models ◽  
Twenty First Century

scholarly journals Seasonal Responses of Terrestrial Carbon Cycle to Climate Variations in CMIP5 Models: Evaluation and Projection

2017 ◽  
Vol 30 (16) ◽  
pp. 6481-6503 ◽  
Author(s):  
Yongwen Liu ◽  
Shilong Piao ◽  
Xu Lian ◽  
Philippe Ciais ◽  
W. Kolby Smith
Keyword(s):  
Temperature Sensitivity ◽  
Boreal Forests ◽  
Net Primary Production ◽  
Coupled Model ◽  
First Century ◽  
Cmip5 Models ◽  
Temperature And Precipitation ◽  
Northern High Latitude ◽  
Twenty First Century ◽  
Subarctic Ecosystems

Seventeen Earth system models (ESMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5) were evaluated, focusing on the seasonal sensitivities of net biome production (NBP), net primary production (NPP), and heterotrophic respiration (Rh) to interannual variations in temperature and precipitation during 1982–2005 and their changes over the twenty-first century. Temperature sensitivity of NPP in ESMs was generally consistent across northern high-latitude biomes but significantly more negative for tropical and subtropical biomes relative to satellite-derived estimates. The temperature sensitivity of NBP in both inversion-based and ESM estimates was generally consistent in March–May (MAM) and September–November (SON) for tropical forests, semiarid ecosystems, and boreal forests. By contrast, for inversion-based NBP estimates, temperature sensitivity of NBP was nonsignificant for June–August (JJA) for all biomes except boreal forest; whereas, for ESM NBP estimates, the temperature sensitivity for JJA was significantly negative for all biomes except shrublands and subarctic ecosystems. Both satellite-derived NPP and inversion-based NBP are often decoupled from precipitation, whereas ESM NPP and NBP estimates are generally positively correlated with precipitation, suggesting that ESMs are oversensitive to precipitation. Over the twenty-first century, changes in temperature sensitivities of NPP, Rh, and NBP are consistent across all RCPs but stronger under more intensive scenarios. The temperature sensitivity of NBP was found to decrease in tropics and subtropics and increase in northern high latitudes in MAM due to an increased temperature sensitivity of NPP. Across all biomes, projected temperature sensitivity of NPP decreased in JJA and SON. Projected precipitation sensitivity of NBP did not change across biomes, except over grasslands in MAM.

scholarly journals Dynamical Downscaling Projections of Twenty-First-Century Atlantic Hurricane Activity: CMIP3 and CMIP5 Model-Based Scenarios

2013 ◽  
Vol 26 (17) ◽  
pp. 6591-6617 ◽  
Author(s):  
Thomas R. Knutson ◽  
Joseph J. Sirutis ◽  
Gabriel A. Vecchi ◽  
Stephen Garner ◽  
Ming Zhao ◽  
...  
Keyword(s):  
Inner Core ◽  
Dynamical Downscaling ◽  
Coupled Model ◽  
First Century ◽  
Cmip5 Models ◽  
Geophysical Fluid Dynamics Laboratory ◽  
Model Intercomparison ◽  
Intercomparison Project ◽  
Hurricane Activity ◽  
Twenty First Century

Abstract Twenty-first-century projections of Atlantic climate change are downscaled to explore the robustness of potential changes in hurricane activity. Multimodel ensembles using the phase 3 of the Coupled Model Intercomparison Project (CMIP3)/Special Report on Emissions Scenarios A1B (SRES A1B; late-twenty-first century) and phase 5 of the Coupled Model Intercomparison Project (CMIP5)/representative concentration pathway 4.5 (RCP4.5; early- and late-twenty-first century) scenarios are examined. Ten individual CMIP3 models are downscaled to assess the spread of results among the CMIP3 (but not the CMIP5) models. Downscaling simulations are compared for 18-km grid regional and 50-km grid global models. Storm cases from the regional model are further downscaled into the Geophysical Fluid Dynamics Laboratory (GFDL) hurricane model (9-km inner grid spacing, with ocean coupling) to simulate intense hurricanes at a finer resolution. A significant reduction in tropical storm frequency is projected for the CMIP3 (−27%), CMIP5-early (−20%) and CMIP5-late (−23%) ensembles and for 5 of the 10 individual CMIP3 models. Lifetime maximum hurricane intensity increases significantly in the high-resolution experiments—by 4%–6% for CMIP3 and CMIP5 ensembles. A significant increase (+87%) in the frequency of very intense (categories 4 and 5) hurricanes (winds ≥ 59 m s−1) is projected using CMIP3, but smaller, only marginally significant increases are projected (+45% and +39%) for the CMIP5-early and CMIP5-late scenarios. Hurricane rainfall rates increase robustly for the CMIP3 and CMIP5 scenarios. For the late-twenty-first century, this increase amounts to +20% to +30% in the model hurricane’s inner core, with a smaller increase (~10%) for averaging radii of 200 km or larger. The fractional increase in precipitation at large radii (200–400 km) approximates that expected from environmental water vapor content scaling, while increases for the inner core exceed this level.

scholarly journals Future Changes in Climate over the Arabian Peninsula based on CMIP6 Multimodel Simulations

2020 ◽  
Vol 4 (4) ◽  
pp. 611-630
Author(s):  
Mansour Almazroui ◽  
M. Nazrul Islam ◽  
Sajjad Saeed ◽  
Fahad Saeed ◽  
Muhammad Ismail
Keyword(s):  
Confidence Level ◽  
Climate Models ◽  
Arabian Peninsula ◽  
Ghg Emissions ◽  
Coupled Model ◽  
First Century ◽  
Cmip5 Models ◽  
Temperature And Precipitation ◽  
Twenty First Century ◽  
Far Future

AbstractThis paper presents the changes in projected temperature and precipitation over the Arabian Peninsula for the twenty-first century using the Coupled Model Intercomparison Project phase 6 (CMIP6) dataset. The changes are obtained by analyzing the multimodel ensemble from 31 CMIP6 models for the near (2030–2059) and far (2070–2099) future periods, with reference to the base period 1981–2010, under three future Shared Socioeconomic Pathways (SSPs). Observations show that the annual temperature is rising at the rate of 0.63 ˚C decade–1 (significant at the 99% confidence level), while annual precipitation is decreasing at the rate of 6.3 mm decade–1 (significant at the 90% confidence level), averaged over Saudi Arabia. For the near (far) future period, the 66% likely ranges of annual-averaged temperature is projected to increase by 1.2–1.9 (1.2–2.1) ˚C, 1.4–2.1 (2.3–3.4) ˚C, and 1.8–2.7 (4.1–5.8) ˚C under SSP1–2.6, SSP2–4.5, and SSP5–8.5, respectively. Higher warming is projected in the summer than in the winter, while the Northern Arabian Peninsula (NAP) is projected to warm more than Southern Arabian Peninsula (SAP), by the end of the twenty-first century. For precipitation, a dipole-like pattern is found, with a robust increase in annual mean precipitation over the SAP, and a decrease over the NAP. The 66% likely ranges of annual-averaged precipitation over the whole Arabian Peninsula is projected to change by 5 to 28 (–3 to 29) %, 5 to 31 (4 to 49) %, and 1 to 38 (12 to 107) % under SSP1–2.6, SSP2–4.5, and SSP5–8.5, respectively, in the near (far) future. Overall, the full ranges in CMIP6 remain higher than the CMIP5 models, which points towards a higher climate sensitivity of some of the CMIP6 climate models to greenhouse gas (GHG) emissions as compared to the CMIP5. The CMIP6 dataset confirmed previous findings of changes in future climate over the Arabian Peninsula based on CMIP3 and CMIP5 datasets. The results presented in this study will be useful for impact studies, and ultimately in devising future policies for adaptation in the region.

scholarly journals Trends in CMIP5 Rainfall Patterns over Southwestern Australia

2017 ◽  
Vol 30 (5) ◽  
pp. 1779-1788 ◽  
Author(s):  
Bhupendra A. Raut ◽  
Michael J. Reeder ◽  
Christian Jakob
Keyword(s):  
Summer Rainfall ◽  
First Century ◽  
Cmip5 Models ◽  
Historical Period ◽  
Gradual Reduction ◽  
Winter Rainfall ◽  
Light Rain ◽  
Southwestern Australia ◽  
Rainfall Patterns ◽  
Twenty First Century

Abstract Previous work has shown that the sharp fall in winter rainfall over coastal southwestern Australia in the 1970s was mainly due to a fall in the frequency of fronts; the gradual reduction in rainfall since the late 1990s was due to a reduction in the number of light-rain days; and the increased inland summer rainfall in the 1970s was due to an increased number of easterly troughs. The current paper extends this earlier work by identifying the rainfall patterns in the region in 14 CMIP5 models for the period 1980–2005 and by calculating how these patterns are projected to change in the twenty-first century. The patterns are identified using k-means clustering of the rainfall, which are validated against observed rainfall clusters. Although the agreement between the models and the observation is generally good, the models underestimate the frequency of raining fronts. In both representative concentration pathway 4.5 and 8.5 (RCP4.5 and RCP8.5) scenarios the number of dry days increases significantly at the expense of light-rain days and frontal rainfall. However, these trends are twice as large in the RCP8.5 scenario as in the RCP4.5 scenario. The reduction in the rainfall from the historical period to the second half of the twenty-first century is produced mainly by a reduction in both the frequency and intensity of light rain and a reduction in the frequency of fronts in the westerlies.

Twenty-first-century projections of North Atlantic tropical storms from CMIP5 models

2012 ◽  
Vol 2 (8) ◽  
pp. 604-607 ◽  
Author(s):  
Gabriele Villarini ◽  
Gabriel A. Vecchi
Keyword(s):  
North Atlantic ◽  
First Century ◽  
Cmip5 Models ◽  
Tropical Storms ◽  
Twenty First Century

scholarly journals CMIP5 Diversity in Southern Westerly Jet Projections Related to Historical Sea Ice Area: Strong Link to Strengthening and Weak Link to Shift

2017 ◽  
Vol 31 (1) ◽  
pp. 195-211 ◽  
Author(s):  
Thomas J. Bracegirdle ◽  
Patrick Hyder ◽  
Caroline R. Holmes
Keyword(s):  
Sea Ice ◽  
Weak Link ◽  
Coupled Model ◽  
First Century ◽  
Sea Surface ◽  
Cmip5 Models ◽  
Cross Model ◽  
Near Surface ◽  
Westerly Jet ◽  
Twenty First Century

Abstract A major feature of projected changes in Southern Hemisphere climate under future scenarios of increased greenhouse gas concentrations is the poleward shift and strengthening of the main eddy-driven belt of midlatitude, near-surface westerly winds (the westerly jet). However, there is large uncertainty in projected twenty-first-century westerly jet changes across different climate models. Here models from the World Climate Research Programme’s phase 5 of the Coupled Model Intercomparison Project (CMIP5) were evaluated to assess linkages between diversity in simulated sea ice area (SIA), Antarctic amplification, and diversity in projected twenty-first-century changes in the westerly jet following the representative concentration pathway 8.5 (RCP8.5) scenario. To help disentangle cause and effect in the coupled model analysis, uncoupled atmosphere-only fixed sea surface experiments from CMIP5 were also evaluated. It is shown that across all seasons, approximately half of the variance in projected RCP8.5 jet strengthening is explained statistically by intermodel differences in simulated historical SIA, whereby CMIP5 models with larger baseline SIA exhibit more ice retreat and less jet strengthening in the future. However, links to jet shift are much weaker and are only statistically significant in austral autumn and winter. It is suggested that a significant cross-model correlation between historical jet strength and projected strength change (r = −0.58) is, at least in part, a result of atmospherically driven historical SIA biases, which then feed back into the atmosphere in future projections. The results emphasize that SIA appears to act in concert with proximal changes in sea surface temperature gradients in relation to model diversity in westerly jet projections.

scholarly journals Winter and Summer Northern Hemisphere Blocking in CMIP5 Models

2013 ◽  
Vol 26 (18) ◽  
pp. 7044-7059 ◽  
Author(s):  
Giacomo Masato ◽  
Brian J. Hoskins ◽  
Tim Woollings
Keyword(s):  
High Latitude ◽  
Storm Track ◽  
Coupled Model ◽  
First Century ◽  
Cmip5 Models ◽  
High Emission ◽  
Poleward Shift ◽  
Intercomparison Project ◽  
Twenty First Century ◽  
High Emission Scenario

Abstract The frequencies of atmospheric blocking in both winter and summer and the changes in them from the twentieth to the twenty-first centuries as simulated in 12 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are analyzed. The representative concentration pathway 8.5 (RCP8.5) high emission scenario runs are used to represent the twenty-first century. The analysis is based on the wave-breaking methodology of Pelly and Hoskins. It differs from the Tibaldi and Molteni index in viewing equatorward cutoff lows and poleward blocking highs in equal manner as indicating a disruption to the westerlies. One-dimensional and two-dimensional diagnostics are applied to identify blocking of the midlatitude storm track and also at higher latitudes. Winter blocking frequency is found to be generally underestimated. The models give a decrease in the European blocking maximum in the twenty-first century, consistent with the results in other studies. There is a mean twenty-first-century winter poleward shift of high-latitude blocking but little agreement between the models on the details. In summer, Eurasian blocking is also underestimated in the models, whereas it is now too large over the high-latitude ocean basins. A decrease in European blocking frequency in the twenty-first-century model runs is again found. However, in summer there is a clear eastward shift of blocking over eastern Europe and western Russia, in a region close to the blocking that dominated the Russian summer of 2010. While summer blocking decreases in general, the poleward shift of the storm track into the region of frequent high-latitude blocking may mean that the incidence of storms being obstructed by blocks may actually increase.

Evaluating CMIP5 models using GPS radio occultation COSMIC temperature in UTLS region during 2006–2013: twenty-first century projection and trends

2016 ◽  
Vol 47 (9-10) ◽  
pp. 3253-3270 ◽  
Author(s):  
P. Kishore ◽  
Ghouse Basha ◽  
M. Venkat Ratnam ◽  
Isabella Velicogna ◽  
T. B. M. J. Ouarda ◽  
...  
Keyword(s):  
Radio Occultation ◽  
First Century ◽  
Cmip5 Models ◽  
Gps Radio Occultation ◽  
Twenty First Century

scholarly journals Tracing Future Spring and Summer Drying in Southern Africa to Tropical Lows and the Congo Air Boundary

2020 ◽  
Vol 33 (14) ◽  
pp. 6205-6228
Author(s):  
Emma Howard ◽  
Richard Washington
Keyword(s):  
Southern Africa ◽  
Austral Summer ◽  
Summer Rainfall ◽  
First Century ◽  
Cmip5 Models ◽  
Spatial Change ◽  
Wet Season ◽  
Austral Spring ◽  
Future Projections ◽  
Twenty First Century

AbstractIn southern Africa, models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) predict robust future drying associated with a delayed rainy-season onset in the austral spring and a range of wetting and drying patterns in the austral summer. This paper relates these rainfall changes to dynamical shifts in two classes of weather systems: the Congo Air Boundary (CAB) and tropical lows. Objective algorithms are used to track these features in CMIP5 model output. It is then established that the climatological locations and frequencies of these systems are reasonably well represented in the CMIP5 models. RCP8.5 end-of-twenty-first-century projections are compared with historical end-of-twentieth-century simulations. Future projections in tropical-low locations and frequencies diverge, but indicate an overall average decrease of 15% and in some cases a northward shift. The projected spatial change in the tropical-low frequency distribution is weakly positively correlated to the projected spatial change in the austral summer rainfall distribution. Meanwhile, future projections indicate a 13% increase in CAB frequency from October to December. This is associated with the gradual climatological CAB breakdown occurring half a month later on average in end-of-twenty-first-century RCP8.5 projections. A delay in the gradual seasonal decline of the CAB prevents rainfall to the south of the CAB’s mean position, most of which is shown to occur on CAB breakdown days, hence creating the austral spring drying signal and delayed wet-season onset. Intermodel variability in the magnitude of CAB frequency increase is able to explain intermodel variability in the projected drying.

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