Arctic Sea Ice in CMIP6

Geophysical Research Letters, Journal Year: 2020, Volume and Issue: 47(10)

Published: April 17, 2020

Abstract We examine CMIP6 simulations of Arctic sea‐ice area and volume. find that models produce a wide spread mean area, capturing the observational estimate within multimodel ensemble spread. The provides more realistic sensitivity September to given amount anthropogenic CO 2 emissions global warming, compared with earlier CMIP experiments. Still, most fail simulate at same time plausible evolution surface temperature. In vast majority available simulations, Ocean becomes practically free (sea‐ice <1 × 10 6 km ) in for first before Year 2050 each four emission scenarios SSP1‐1.9, SSP1‐2.6, SSP2‐4.5, SSP5‐8.5 examined here.

Language: Английский

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When will the summer Arctic be nearly sea ice free?

Geophysical Research Letters, Journal Year: 2013, Volume and Issue: 40(10), P. 2097 - 2101

Published: March 5, 2013

Abstract The observed rapid loss of thick multiyear sea ice over the last 7 years and September 2012 Arctic extent reduction 49% relative to 1979–2000 climatology are inconsistent with projections a nearly ice‐free summer from model estimates 2070 beyond made just few ago. Three recent approaches predictions in scientific literature as follows: (1) extrapolation volume data, (2) assuming several more events such 2007 2012, (3) climate projections. Time horizons for these three roughly 2020 or earlier, 2030 ± 10 years, 2040 later. Loss models based on subset most ensemble members. It is not possible clearly choose one approach another this depends weights given data versus models. Observations citations support conclusion that global results CMIP5 archive too conservative their Recent expert opinion should be considered addition advance very likely timing future first half 21st century, possibility major within decade two.

Language: Английский

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Observed Arctic sea-ice loss directly follows anthropogenic CO ₂ emission

Science, Journal Year: 2016, Volume and Issue: 354(6313), P. 747 - 750

Published: Nov. 4, 2016

Arctic sea ice is retreating rapidly, raising prospects of a future ice-free Ocean during summer. Because climate-model simulations the sea-ice loss differ substantially, we used robust linear relationship between monthly-mean September area and cumulative carbon dioxide (CO2) emissions to infer evolution summer directly from observational record. The observed implies sustained 3 ± 0.3 square meters per metric ton CO2 emission. On basis this sensitivity, will be lost throughout for an additional 1000 gigatons emissions. Most models show lower which possibly linked underestimation modeled increase in incoming longwave radiation transient climate response.

Language: Английский

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The Met Office Hadley Centre sea ice and sea surface temperature data set, version 2: 1. Sea ice concentrations

Journal of Geophysical Research Atmospheres, Journal Year: 2014, Volume and Issue: 119(6), P. 2864 - 2889

Published: Jan. 4, 2014

We present a new version of the sea ice concentration component Met Office Hadley Centre and surface temperature data set, HadISST.2.1.0.0. Passive microwave are combined with historical sources, such as charts, to create global analyses on 1° grid from 1850 2007. Climatology was used when no information about available. Our main aim homogenous set by calculating applying bias adjustments using periods overlaps between different sources used. National Ice Center charts 1995 2007 have been reference achieve this. In particular, large applied passive in both Antarctic Arctic summers. Overall, HadISST.2.1.0.0 contains more than HadISST1.1, higher concentrations, shorter marginal zones, larger extents areas some regions periods. A method for estimating concentrations within pack distance edge has developed evaluated. This only were known or original fields heterogeneous. number discontinuities HadISST1.1 record longer found

Language: Английский

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Structure and Performance of GFDL's CM4.0 Climate Model

Journal of Advances in Modeling Earth Systems, Journal Year: 2019, Volume and Issue: 11(11), P. 3691 - 3727

Published: Oct. 31, 2019

We describe the Geophysical Fluid Dynamics Laboratory's CM4.0 physical climate model, with emphasis on those aspects that may be of particular importance to users this model and its simulations. The is built AM4.0/LM4.0 atmosphere/land OM4.0 ocean model. Topics include rationale for key choices made in formulation, stability as well drift preindustrial control simulation, comparison historical simulations observations from recent decades. Notable achievements relatively small biases seasonal spatial patterns top-of-atmosphere fluxes, surface temperature, precipitation; reduced double Intertropical Convergence Zone bias; dramatically improved representation boundary currents; a high-quality simulation climatological Arctic sea ice extent decline; excellent El Niño-Southern Oscillation spectrum structure. Areas concern inadequate deep convection Nordic Seas; an inaccurate Antarctic simulation; precipitation wind composites still affected by equatorial cold tongue muted variability Atlantic Meridional Overturning Circulation; strong 100 year quasiperiodicity Southern Ocean ventilation; lack warming before 1990 too rapid thereafter due high sensitivity aerosol forcing, contrast observational record. Overall, scores very fidelity against compared Coupled Model Intercomparison Project Phase 5 generation terms both mean state modes should prove valuable new addition analysis across broad array applications.

Language: Английский

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Seasonal and Regional Manifestation of Arctic Sea Ice Loss

Journal of Climate, Journal Year: 2018, Volume and Issue: 31(12), P. 4917 - 4932

Published: March 27, 2018

The Arctic Ocean is currently on a fast track toward seasonally ice-free conditions. Although most attention has been the accelerating summer sea ice decline, large changes are also occurring in winter. This study assesses past, present, and possible future change regional Northern Hemisphere extent throughout year by examining concentration based observations back to 1950, including satellite record since 1979. At variability dominate perennial ice-covered Beaufort, Chukchi, East Siberian, Laptev, Kara Seas, with Siberian Sea explaining largest fraction of September loss (22%). Winter occur seas farther south: Barents Sea, Okhotsk, Greenland Baffin Bay, carrying March (27%). distinct regions winter have generally consistent but appear at present be transformation as result rapid all seasons. As become free, will dominated appears first free September. Remaining observed trends, shelf estimated 2020s, south year-round from 2050s.

Language: Английский

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A sea ice free summer Arctic within 30 years: An update from CMIP5 models

Geophysical Research Letters, Journal Year: 2012, Volume and Issue: 39(18)

Published: Aug. 13, 2012

Three years ago we proposed that the summer Arctic would be nearly sea ice free by 2030s; “nearly” is interpreted as extent less than 1.0 million km 2 . We consider this estimate to still valid based on projections of updated climate models (CMIP5) and observational data. Similar previous (CMIP3), CMIP5 shows a wide spread in hindcast projected loss among different models. Further, there no consensus scientific literature for cause such results CMIP3 CMIP5. While model mean extents are closer observations CMIP3, rates reduction most runs slow relative recent observations. All do show due increased anthropogenic forcing pre‐industrial control runs. Applying same technique selection extrapolation approach used our paper, interval range 14 36 years, with median value 28 years. Relative 2007 baseline, suggests 2030s.

Language: Английский

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Freshwater and its role in the Arctic Marine System: Sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans

Journal of Geophysical Research Biogeosciences, Journal Year: 2015, Volume and Issue: 121(3), P. 675 - 717

Published: Oct. 12, 2015

Abstract The Arctic Ocean is a fundamental node in the global hydrological cycle and ocean's thermohaline circulation. We here assess system's key functions processes: (1) delivery of fresh low‐salinity waters to by river inflow, net precipitation, distillation during freeze/thaw cycle, Pacific inflows; (2) disposition (e.g., sources, pathways, storage) freshwater components within Ocean; (3) release export into bordering convective domains North Atlantic. then examine physical, chemical, or biological processes which are influenced constrained local quantities geochemical qualities freshwater; these include stratification vertical mixing, ocean heat flux, nutrient supply, primary production, acidification, biogeochemical cycling. Internal joint effects sea ice decline intensification have strengthened coupling between atmosphere wind drift stresses, solar radiation, moisture exchange), drainage basins discharge, sediment transport, erosion), terrestrial ecosystems greening, dissolved particulate carbon loading, altered phenology biotic components). External acts as both constraint necessary ingredient for deep convection subarctic gyres thus affects Geochemical fingerprints attained likewise exported neighboring systems beyond. Finally, we discuss observed modeled changes this system on seasonal, annual, decadal time scales mechanisms that link marine atmospheric, terrestrial, cryospheric systems.

Language: Английский

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Spring snow cover extent reductions in the 2008–2012 period exceeding climate model projections

Geophysical Research Letters, Journal Year: 2012, Volume and Issue: 39(19)

Published: Sept. 17, 2012

Analysis of Northern Hemisphere spring terrestrial snow cover extent (SCE) from the NOAA chart Climate Data Record (CDR) for April to June period (when is mainly located over Arctic) has revealed statistically significant reductions in May and SCE. Successive records lowest SCE have been set each year Eurasia since 2008, 3 past 5 years North America. The rate loss between 1979 2011 (−17.8% decade −1 ) greater than September sea ice (−10.6% same period. Coupled Model Intercomparison Project Phase (CMIP5) model output shows marked observed 2005 fall below zone consensus defined by +/−1 standard deviation multi‐model ensemble mean.

Language: Английский

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Ch. 2: Our Changing Climate. Climate Change Impacts in the United States: The Third National Climate Assessment

Published: Jan. 1, 2014

Language: Английский

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