Rapid neoglaciation on Ellesmere Island promoted by enhanced summer snowfall in a transient climate model simulation of the middle-late-Holocene

The Holocene ◽  
2020 ◽  
Vol 30 (10) ◽  
pp. 1474-1480
Author(s):  
Stephen J Vavrus ◽  
Feng He ◽  
John E Kutzbach ◽  
William F Ruddiman

Arctic neoglaciation following the Holocene Thermal Maximum is an important feature of late-Holocene climate. We investigated this phenomenon using a transient 6000-year simulation with the CESM-CAM5 climate model driven by orbital forcing, greenhouse gas concentrations, and a land use reconstruction. During the first three millennia analyzed here (6–3 ka), mean Arctic snow depth increases, despite enhanced greenhouse forcing. Superimposed on this secular trend is a very abrupt increase in snow depth between 5 and 4.9 ka on Ellesmere Island and the Greenland coasts, in rough agreement with the timing of observed neoglaciation in the region. This transition is especially extreme on Ellesmere Island, where end-of-summer snow coverage jumps from nearly 0 to virtually 100% in 1 year, and snow depth increases to the model’s imposed maximum within 15 years. This climatic shift involves more than the Milankovitch-based expectation of cooler summers causing less snow melt. Coincident with the onset of the cold regime are two consecutive summers with heavy snowfall on Ellesmere Island that help to short-circuit the normal seasonal melt cycle. These heavy snow seasons are caused by synoptic-scale, cyclonic circulation anomalies over the Arctic Ocean and Canadian Archipelago, including an extremely positive phase of the Arctic Oscillation. Our study reveals that a climate model can produce sudden climatic transitions in this region prone to glacial inception and exceptional variability, due to a dynamic mechanism (more summer snowfall induced by an extreme circulation anomaly) that augments the traditional Milankovitch thermodynamic explanation of orbitally induced glacier development.

2019 ◽  
Vol 5 (12) ◽  
pp. eaax8203 ◽  
Author(s):  
Hyo-Seok Park ◽  
Seong-Joong Kim ◽  
Andrew L. Stewart ◽  
Seok-Woo Son ◽  
Kyong-Hwan Seo

The Holocene thermal maximum was characterized by strong summer solar heating that substantially increased the summertime temperature relative to preindustrial climate. However, the summer warming was compensated by weaker winter insolation, and the annual mean temperature of the Holocene thermal maximum remains ambiguous. Using multimodel mid-Holocene simulations, we show that the annual mean Northern Hemisphere temperature is strongly correlated with the degree of Arctic amplification and sea ice loss. Additional model experiments show that the summer Arctic sea ice loss persists into winter and increases the mid- and high-latitude temperatures. These results are evaluated against four proxy datasets to verify that the annual mean northern high-latitude temperature during the mid-Holocene was warmer than the preindustrial climate, because of the seasonally rectified temperature increase driven by the Arctic amplification. This study offers a resolution to the “Holocene temperature conundrum”, a well-known discrepancy between paleo-proxies and climate model simulations of Holocene thermal maximum.


2012 ◽  
Vol 13 (2) ◽  
pp. 443-462 ◽  
Author(s):  
Marco Braun ◽  
Daniel Caya ◽  
Anne Frigon ◽  
Michel Slivitzky

Abstract The effect of a regional climate model’s (RCM’s) internal variability (IV) on climate statistics of annual series of hydrological variables is investigated at the scale of 21 eastern Canada watersheds in Quebec and Labrador. The analysis is carried out on 30-yr pairs of simulations (twins), performed with the Canadian Regional Climate Model (CRCM) for present (reanalysis and global climate model driven) and future (global climate model driven) climates. The twins differ only by the starting date of the regional simulation—a standard procedure used to trigger internal variability in RCMs. Two different domain sizes are considered: one comparable to domains used for RCM simulations over Europe and the other comparable to domains used for North America. Results for the larger North American domain indicate that mean relative differences between twin pairs of 30-yr climates reach ±5% when spectral nudging is used. Larger differences are found for extreme annual events, reaching about ±10% for 10% and 90% quantiles (Q10 and Q90). IV is smaller by about one order of magnitude in the smaller domain. Internal variability is unaffected by the period (past versus future climate) and by the type of driving data (reanalysis versus global climate model simulation) but shows a dependence on watershed size. When spectral nudging is deactivated in the large domain, the relative difference between pairs of 30-yr climate means almost doubles and approaches the magnitude of a global climate model’s internal variability. This IV at the level of the natural climate variability has a profound impact on the interpretation, analysis, and validation of RCM simulations over large domains.


2005 ◽  
Vol 32 (17) ◽  
Author(s):  
K. Tourpali ◽  
C. J. E. Schuurmans ◽  
R. van Dorland ◽  
B. Steil ◽  
C. Brühl ◽  
...  

2015 ◽  
Vol 28 (13) ◽  
pp. 5030-5040 ◽  
Author(s):  
Hyo-Seok Park ◽  
Sukyoung Lee ◽  
Seok-Woo Son ◽  
Steven B. Feldstein ◽  
Yu Kosaka

Abstract The surface warming in recent decades has been most rapid in the Arctic, especially during the winter. Here, by utilizing global reanalysis and satellite datasets, it is shown that the northward flux of moisture into the Arctic during the winter strengthens the downward infrared radiation (IR) by 30–40 W m−2 over 1–2 weeks. This is followed by a decline of up to 10% in sea ice concentration over the Greenland, Barents, and Kara Seas. A climate model simulation indicates that the wind-induced sea ice drift leads the decline of sea ice thickness during the early stage of the strong downward IR events, but that within one week the cumulative downward IR effect appears to be dominant. Further analysis indicates that strong downward IR events are preceded several days earlier by enhanced convection over the tropical Indian and western Pacific Oceans. This finding suggests that sea ice predictions can benefit from an improved understanding of tropical convection and ensuing planetary wave dynamics.


2018 ◽  
Vol 9 (4) ◽  
pp. 209-217
Author(s):  
Li-Quan WU ◽  
Qing-Quan LI ◽  
Yi-Hui DING ◽  
Li-Juan WANG ◽  
Xiao-Ge XIN ◽  
...  

2018 ◽  
Vol 18 (7) ◽  
pp. 5001-5019 ◽  
Author(s):  
Erkki Kyrölä ◽  
Monika E. Andersson ◽  
Pekka T. Verronen ◽  
Marko Laine ◽  
Simo Tukiainen ◽  
...  

Abstract. Most of our understanding of the atmosphere is based on observations and their comparison with model simulations. In middle atmosphere studies it is common practice to use an approach, where the model dynamics are at least partly based on temperature and wind fields from an external meteorological model. In this work we test how closely satellite measurements of a few central trace gases agree with this kind of model simulation. We use collocated vertical profiles where each satellite measurement is compared to the closest model data. We compare profiles and distributions of O3, NO2 and NO3 from the Global Ozone Monitoring by Occultation of Stars instrument (GOMOS) on the Envisat satellite with simulations by the Whole Atmosphere Community Climate Model (WACCM). GOMOS measurements are from nighttime. Our comparisons show that in the stratosphere outside the polar regions differences in ozone between WACCM and GOMOS are small, between 0 and 6%. The correlation of 5-day time series show a very high 0.9–0.95. In the tropical region 10° S–10° N below 10 hPa WACCM values are up to 20 % larger than GOMOS. In the Arctic below 6 hPa WACCM ozone values are up to 20 % larger than GOMOS. In the mesosphere between 0.04 and 1 hPa the WACCM is at most 20 % smaller than GOMOS. Above the ozone minimum at 0.01 hPa (or 80 km) large differences are found between WACCM and GOMOS. The correlation can still be high, but at the second ozone peak the correlation falls strongly and the ozone abundance from WACCM is about 60 % smaller than that from GOMOS. The total ozone columns (above 50 hPa) of GOMOS and WACCM agree within ±2 % except in the Arctic where WACCM is 10 % larger than GOMOS. Outside the polar areas and in the validity region of GOMOS NO2 measurements (0.3–37 hPa) WACCM and GOMOS NO2 agree within −5 to +25 % and the correlation is high (0.7–0.95) except in the upper stratosphere at the southern latitudes. In the polar areas, where solar particle precipitation and downward transport from the thermosphere enhance NO2 abundance, large differences up to −90 % are found between WACCM and GOMOS NO2 and the correlation varies between 0.3 and 0.9. For NO3, we find that the WACCM and GOMOS difference is between −20 and 5 % with a very high correlation of 0.7–0.95. We show that NO3 values strongly depend on temperature and the dependency can be fitted by the exponential function of temperature. The ratio of NO3 to O3 from WACCM and GOMOS closely follow the prediction from the equilibrium chemical theory. Abrupt temperature increases from sudden stratospheric warmings (SSWs) are reflected as sudden enhancements of WACCM and GOMOS NO3 values.


2015 ◽  
Vol 15 (16) ◽  
pp. 22013-22045
Author(s):  
L. Thölix ◽  
L. Backman ◽  
R. Kivi ◽  
A. Karpechko

Abstract. This study evaluates the stratospheric water vapour distribution and variability in the Arctic. A FinROSE chemistry climate model simulation covering years 1990–2013 is compared to observations (satellite and frostpoint hygrometer soundings) and the sources of stratospheric water vapour are studied. According to observations and the simulations the water vapour concentration in the Arctic stratosphere started to increase after year 2006, but around 2011 the concentration started to decrease. Model calculations suggest that the increase in water vapour during 2006–2011 (at 56 hPa) is mostly explained by transport related processes, while the photochemically produced water vapour plays a relatively smaller role. The water vapour trend in the stratosphere may have contributed to increased ICE PSC occurrence. The increase of water vapour in the precense of the low winter temperatures in the Arctic stratosphere led to more frequent occurrence of ICE PSCs in the Arctic vortex. The polar vortex was unusually cold in early 2010 and allowed large scale formation of the polar stratospheric clouds. The cold pool in the stratosphere over the Northern polar latitudes was large and stable and a large scale persistent dehydration was observed. Polar stratospheric ice clouds and dehydration were observed at Sodankylä with accurate water vapour soundings in January and February 2010 during the LAPBIAT atmospheric sounding campaign. The observed changes in water vapour were reproduced by the model. Both the observed and simulated decrease of the water vapour in the dehydration layer was up to 1.5 ppm.


2020 ◽  
Author(s):  
Kouji Adachi ◽  
Naga Oshima ◽  
Sho Ohata ◽  
Atsushi Yoshida ◽  
Nobuhiro Moteki ◽  
...  

Abstract. Aerosol particles were collected at various altitudes in the Arctic during the Polar Airborne Measurements and Arctic Regional Climate Model Simulation Project (PAMARCMiP 2018) conducted in the early spring of 2018. The composition, size, number fraction, and mixing state of individual aerosol particles were analyzed using transmission electron microscopy (TEM), and their sources and transport were evaluated by numerical model simulations. We found that sulfate, sea-salt, mineral-dust, K-bearing, and carbonaceous particles were the major aerosol constituents and were internally mixed. The number fraction of mineral-dust and sea-salt particles decreased with increasing altitude. The K-bearing particles increased within a biomass burning (BB) plume at altitudes > 3900 m, which originated from Siberia. Chlorine in sea-salt particles was replaced with sulfate at high altitudes. These results suggest that the sources, transport, and aging of Arctic aerosols largely vary depending on the altitude and airmass history. We also provide the occurrences of solid-particle inclusions (soot, fly-ash, and Fe-aggregate particles), some of which are light-absorbing and potential ice-nucleating particles. Our TEM measurements revealed, for the first time, the detailed mixing state of individual particles at various altitudes in the Arctic. This information facilitates the accurate evaluation of the aerosol influences on Arctic haze, radiation balance, cloud formation, and snow/ice albedo when deposited.


2007 ◽  
Vol 64 (3) ◽  
pp. 887-904 ◽  
Author(s):  
Mario Sempf ◽  
Klaus Dethloff ◽  
Dörthe Handorf ◽  
Michael V. Kurgansky

Abstract Dynamical mechanisms of atmospheric regime behavior are investigated in the context of a quasigeostrophic three-level T21 model of the wintertime atmospheric circulation over the Northern Hemisphere. The model, driven by realistic orography and using a thermal forcing determined by a newly developed tuning procedure, is shown to possess a reasonable climatology and to simulate the Arctic Oscillation quite realistically. It exhibits pronounced internally generated interannual and decadal variability and, in particular, circulation regimes that agree fairly well with observed ones. Two known hypotheses about the origin of regime behavior, as it occurs in the model herein are addressed: (i) multiple equilibria and (ii) chaotic itinerancy between attractor ruins. The first hypothesis is falsified at very high probability, while the second is likely to be true.


2010 ◽  
Vol 73 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Matthew Peros ◽  
Konrad Gajewski ◽  
Tara Paull ◽  
Rebecca Ravindra ◽  
Brandi Podritske

A sediment core from Lake BC01 (75"10.945?N, 111"55.181?W, 225"m asl) on south-central Melville Island, NWT, Canada, provides the first continuous postglacial environmental record for the region. Fossil pollen results indicate that the postglacial landscape was dominated by Poaceae andSalix, typical of a High Arctic plant community, whereas the Arctic herbOxyriaunderwent a gradual increase during the late Holocene. Pollen-based climate reconstructions suggests the presence of a cold and dry period ~12,000"cal yr BP, possibly representing the Younger Dryas, followed by warmer and wetter conditions from 11,000 to 5000"cal yr BP, likely reflective of the Holocene Thermal Maximum. The climate then underwent a gradual cooling and drying from 5000"cal yr BP to the present, suggesting a late Holocene neoglacial cooling. Diatom preservation was poor prior to 5000"cal yr BP, when conditions were warmest, suggesting that diatom dissolution may in part be climatically controlled. Diatom concentrations were highest ~4500"cal yr BP but then decreased substantially by 3500"cal yr BP and remained low before recovering slightly in the 20th century. An abrupt warming occurred during the past 70 yr at the site, although the magnitude of this warming did not exceed that of the early Holocene.


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