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Role of Atmospheric Variability in Driving the "Warm-Arctic, Cold-Continent" Pattern Over the North America Sector and Sea Ice Variability Over the Chukchi-Bering Sea 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2020, 47 (13)
作者:  Guan, Weina;  Jiang, Xianan;  Ren, Xuejuan;  Chen, Gang;  Ding, Qinghua
收藏  |  浏览/下载:15/0  |  提交时间:2020/06/09
Arctic warming  surface air temperature  sea ice loss  atmospheric variability  large-scale circulation  
Patterns and trends of Northern Hemisphere snow mass from 1980 to 2018 期刊论文
NATURE, 2020, 581 (7808) : 294-+
作者:  Ibrahim, Nizar;  Maganuco, Simone;  Dal Sasso, Cristiano;  Fabbri, Matteo;  Auditore, Marco;  Bindellini, Gabriele;  Martill, David M.;  Zouhri, Samir;  Mattarelli, Diego A.;  Unwin, David M.;  Wiemann, Jasmina;  Bonadonna, Davide;  Amane, Ayoub;  Jakubczak, Juliana;  Joger, Ulrich;  Lauder, George V.;  Pierce, Stephanie E.
收藏  |  浏览/下载:18/0  |  提交时间:2020/05/25

Warming surface temperatures have driven a substantial reduction in the extent and duration of Northern Hemisphere snow cover(1-3). These changes in snow cover affect Earth'  s climate system via the surface energy budget, and influence freshwater resources across a large proportion of the Northern Hemisphere(4-6). In contrast to snow extent, reliable quantitative knowledge on seasonal snow mass and its trend is lacking(7-9). Here we use the new GlobSnow 3.0 dataset to show that the 1980-2018 annual maximum snow mass in the Northern Hemisphere was, on average, 3,062 +/- 35 billion tonnes (gigatonnes). Our quantification is for March (the month that most closely corresponds to peak snow mass), covers non-alpine regions above 40 degrees N and, crucially, includes a bias correction based on in-field snow observations. We compare our GlobSnow 3.0 estimates with three independent estimates of snow mass, each with and without the bias correction. Across the four datasets, the bias correction decreased the range from 2,433-3,380 gigatonnes (mean 2,867) to 2,846-3,062 gigatonnes (mean 2,938)-a reduction in uncertainty from 33% to 7.4%. On the basis of our bias-corrected GlobSnow 3.0 estimates, we find different continental trends over the 39-year satellite record. For example, snow mass decreased by 46 gigatonnes per decade across North America but had a negligible trend across Eurasia  both continents exhibit high regional variability. Our results enable a better estimation of the role of seasonal snow mass in Earth'  s energy, water and carbon budgets.


Applying a bias correction to a state-of-the-art dataset covering non-alpine regions of the Northern Hemisphere and to three other datasets yields a more constrained quantification of snow mass in March from 1980 to 2018.


  
Surface Ocean Warming Around Australia Driven by Interannual Variability and Long-Term Trends in Southern Hemisphere Westerlies 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2020, 47 (9)
作者:  Duran, E. R.;  England, M. H.;  Spence, P.
收藏  |  浏览/下载:7/0  |  提交时间:2020/07/02
Tasman Sea  South Australian Basin  Ocean surface warming  Southern Annular Mode  interannual wind variability  Twenty first Century projections  
On the use of averaged indicators to assess lakes' thermal response to changes in climatic conditions 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2020, 15 (3)
作者:  Toffolon, Marco;  Piccolroaz, Sebastiano;  Calamita, Elisa
收藏  |  浏览/下载:9/0  |  提交时间:2020/07/02
Laurentian great lakes  climate change  lake warming  index  lake surface water temperature  stratification  thermal dynamics  
On the relationship between Atlantic meridional overturning circulation slowdown and global surface warming 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2020, 15 (2)
作者:  Caesar, L.;  Rahmstorf, S.;  Feulner, G.
收藏  |  浏览/下载:9/0  |  提交时间:2020/07/02
Atlantic meridional overturning circulation  global surface warming  ocean heat uptake  
Early climate models successfully predicted global warming 期刊论文
NATURE, 2020, 578 (7793) : 45-46
作者:  Bertolucci, Sergio;  Mulargia, Francesco;  Giardini, Domenico
收藏  |  浏览/下载:9/0  |  提交时间:2020/07/03

An evaluation of past climate-model forecasts.


Climate models published between 1970 and 2007 provided accurate forecasts of subsequently observed global surface warming. This finding shows the value of using global observations to vet climate models as the planet warms.


  
The past and future of global river ice 期刊论文
NATURE, 2020, 577 (7788) : 69-+
作者:  Yang, Xiao;  Pavelsky, Tamlin M.;  Allen, George H.
收藏  |  浏览/下载:7/0  |  提交时间:2020/05/13

More than one-third of Earth'  s landmass is drained by rivers that seasonally freeze over. Ice transforms the hydrologic(1,2), ecologic(3,4), climatic(5) and socio-economic(6-8) functions of river corridors. Although river ice extent has been shown to be declining in many regions of the world(1), the seasonality, historical change and predicted future changes in river ice extent and duration have not yet been quantified globally. Previous studies of river ice, which suggested that declines in extent and duration could be attributed to warming temperatures(9,10), were based on data from sparse locations. Furthermore, existing projections of future ice extent are based solely on the location of the 0-degrees C isotherm11. Here, using satellite observations, we show that the global extent of river ice is declining, and we project a mean decrease in seasonal ice duration of 6.10 +/- 0.08 days per 1-degrees C increase in global mean surface air temperature. We tracked the extent of river ice using over 400,000 clear-sky Landsat images spanning 1984-2018 and observed a mean decline of 2.5 percentage points globally in the past three decades. To project future changes in river ice extent, we developed an observationally calibrated and validated model, based on temperature and season, which reduced the mean bias by 87 per cent compared with the 0-degree-Celsius isotherm approach. We applied this model to future climate projections for 2080-2100: compared with 2009-2029, the average river ice duration declines by 16.7 days under Representative Concentration Pathway (RCP) 8.5, whereas under RCP 4.5 it declines on average by 7.3 days. Our results show that, globally, river ice is measurably declining and will continue to decline linearly with projected increases in surface air temperature towards the end of this century.


  
Mass balance of the Greenland Ice Sheet from 1992 to 2018 期刊论文
NATURE, 2020, 579 (7798) : 233-+
作者:  Scudellari, Megan
收藏  |  浏览/下载:11/0  |  提交时间:2020/04/16

The Greenland Ice Sheet has been a major contributor to global sea-level rise in recent decades(1,2), and it is expected to continue to be so(3). Although increases in glacier flow(4-6) and surface melting(7-9) have been driven by oceanic(10-12) and atmospheric(13,14) warming, the magnitude and trajectory of the ice sheet'  s mass imbalance remain uncertain. Here we compare and combine 26 individual satellite measurements of changes in the ice sheet'  s volume, flow and gravitational potential to produce a reconciled estimate of its mass balance. The ice sheet was close to a state of balance in the 1990s, but annual losses have risen since then, peaking at 345 +/- 66 billion tonnes per year in 2011. In all, Greenland lost 3,902 +/- 342 billion tonnes of ice between 1992 and 2018, causing the mean sea level to rise by 10.8 +/- 0.9 millimetres. Using three regional climate models, we show that the reduced surface mass balance has driven 1,964 +/- 565 billion tonnes (50.3 per cent) of the ice loss owing to increased meltwater runoff. The remaining 1,938 +/- 541 billion tonnes (49.7 per cent) of ice loss was due to increased glacier dynamical imbalance, which rose from 46 +/- 37 billion tonnes per year in the 1990s to 87 +/- 25 billion tonnes per year since then. The total rate of ice loss slowed to 222 +/- 30 billion tonnes per year between 2013 and 2017, on average, as atmospheric circulation favoured cooler conditions(15) and ocean temperatures fell at the terminus of Jakobshavn Isbr AE(16). Cumulative ice losses from Greenland as a whole have been close to the rates predicted by the Intergovernmental Panel on Climate Change for their high-end climate warming scenario(17), which forecast an additional 70 to 130 millimetres of global sea-level rise by 2100 compared with their central estimate.


  
Unprecedented Northern Hemisphere Tropical Cyclone Genesis in 2018 Shaped by Subtropical Warming in the North Pacific and the North Atlantic 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2019
作者:  Wang, Chao;  Wang, Bin;  Cao, Jian
收藏  |  浏览/下载:10/0  |  提交时间:2020/02/17
Northern Hemisphere tropical cyclone season  North Pacific subtropical high  subtropical sea surface warming  tropical cyclone genesis  
US temperatures: Time trends and persistence 期刊论文
INTERNATIONAL JOURNAL OF CLIMATOLOGY, 2019, 39 (13) : 5091-5103
作者:  Gil-Alana, Luis A.;  Sauci, Laura
收藏  |  浏览/下载:5/0  |  提交时间:2020/02/17
climate change  fractional integration  global warming  long memory  time trend  surface temperature