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Science museums are important informal science learning environments which have the potential to shape public discourse around topics such as climate change. Planetariums, which have traditionally provided projected, observational experiences to explore topics in astronomy, have evolved to engage different areas of science in live interaction with planetarium staff. The current study analyzes audience experiences of a planetarium show about polar science and climate change, Earth: Pole to Pole, designed jointly by Pacific Science Center and the University of Washington's Polar Science Center. Post-show survey results from general audiences indicated that over 90% of respondents felt that they learned either "some" or "a lot" about polar science, with a moderate increase in interest observed in all subgroups analyzed, but this increase was especially high amongst female respondents. [ABSTRACT FROM AUTHOR]

Greenland ice sheet rainfall is expected to increase under a warming climate. Yet, there have been no active long‐term in‐situ rainfall records on the ice sheet due to observational difficulties. Here, we utilize the state‐of‐the‐art 5 km polar non‐hydrostatic regional climate model NHM‐SMAP to evaluate the ice sheet's rainfall over 40 years (1980–2019). The largest trends include a fourfold increase in annual rainfall for the northwestern ice sheet; 3.1 Gt year−1 or 12 mm m−2 year−1. September ice‐sheet‐wide rainfall amount and intensity increase by 7.5 Gt month−1 and 20.8 mm h−1 year−1. In the last two decades, the increasing September maximum hourly rainfall rate exceeded 50 mm h−1 six times. The increased surface water delivery has numerous implications, including for snow metamorphism and ice flow dynamics. Plain Language Summary: We find that rainfall has increased over the Greenland ice sheet from 1980 to 2019. Among the eight major ice‐sheet drainage areas, the northwestern sector stands out as an increasing rainfall hotspot where the annual rainfall has increased fourfold. For the entire ice sheet, September's total rainfall and its intensity increased by 224% and 54% above the 1981–2010 baseline over the last 40 years. An increase in late melt season rainfall is expected to contribute to an increase in late summer snow and ice melt. Our results provide the first detailed quantification of the state of ice sheet rainfall climatology. Key Points: A 5 km horizontal resolution non‐hydrostatic regional climate model is used to evaluate Greenland ice sheet rainfall from 1980 to 2019The northwestern sector stands out as a hotspot of increasing rainfallBoth the amount and intensity of September ice‐sheet‐wide rainfall have significantly increased in the 40 years from 1980 to 2019 [ABSTRACT FROM AUTHOR]

Mean sea ice thickness is a sensitive indicator of Arctic climate change and is in long-term decline despite significant interannual variability. Current thickness estimations from satellite radar altimeters employ a snow climatology for converting range measurements to sea ice thickness, but this introduces unrealistically low interannual variability and trends. When the sea ice thickness in the period 2002–2018 is calculated using new snow data with more realistic variability and trends, we find mean sea ice thickness in four of the seven marginal seas to be declining between 60 %–100 % faster than when calculated with the conventional climatology. When analysed as an aggregate area, the mean sea ice thickness in the marginal seas is in statistically significant decline for 6 of 7 winter months. This is observed despite a 76 % increase in interannual variability between the methods in the same time period. On a seasonal timescale we find that snow data exert an increasingly strong control on thickness variability over the growth season, contributing 46 % in October but 70 % by April. Higher variability and faster decline in the sea ice thickness of the marginal seas has wide implications for our understanding of the polar climate system and our predictions for its change. [ABSTRACT FROM AUTHOR]

The global temperature has increased approximately 0.9°C over the past 50 years and is projected to continue to increase. Many efforts have been taken to investigate the evolutionary dynamics of climate classification zones in response to the rising temperature. However, the changing dynamics of the spatial climate patterns remain poorly understood. It is thus desired that the unobserved characteristics of the global climate patterns, such as aggregation and subdivision, are explored from the landscape perspective. Here, we demonstrate that the global climate zones have undergone a process of aggregation during the past 100 years and that this dynamic is expected to continue in the future. The climate aggregation effect is especially evident in the Arctic, Tibet, and East Africa. We find that the tropical, arid, temperate, and cold climates are aggregating while the polar climate zone exhibits subdivision. Furthermore, our analysis demonstrates a clear spatial aggregation process with a latitudinal feature. We should pay enough attention to the phenomenon of patch aggregation of global climate landscape pattern, which will undoubtedly help us to deepen our understanding of global climate change and help to further explore the feedback relationship between climate and biological systems. [ABSTRACT FROM AUTHOR]

The ERA5 reanalysis, recently made available by the European Centre for Medium-Range Weather Forecasts (ECMWF), is a new reanalysis product at a high resolution replacing ERA-Interim and is considered to provide the best climate reanalysis over Greenland to date. However, so far little is known about the performance of ERA5 over the Greenland Ice Sheet (GrIS). In this study, we compare the near-surface climate from the new ERA5 reanalysis to ERA-Interim, the Arctic System Reanalysis (ASR) as well as to a state-of-the-art polar regional climate model (MAR). The results show (1) that ERA5 does not outperform ERA-Interim significantly when compared with near-surface climate observations over GrIS, but ASR better models the near-surface temperature than both ERA reanalyses. (2) Polar regional climate models (e.g., MAR) are still a useful tool to downscale the GrIS climate compared to ERA5, as in particular the near-surface temperature in summer has a key role for representing snow and ice processes such as the surface melt. However, assimilating satellite data and using a more recent radiative scheme enable both ERA and ASR reanalyses to represent more satisfactorily than MAR the downward solar and infrared fluxes. (3) MAR near-surface climate is not affected when forced at its lateral boundaries by either ERA5 or ERA-Interim. Therefore, forcing polar regional climate models with ERA5 starting from 1950 will enable long and homogeneous surface mass balance reconstructions. [ABSTRACT FROM AUTHOR]

Ice sheets provide exceptional archives of past changes in polar climate, regional environment and global atmospheric composition. The oldest dated deep ice core drilled in Antarctica has been retrieved at EPICA Dome C (EDC), reaching ~800 000 years. Obtaining an older paleoclimatic record from Antarctica is one of the greatest challenges of the ice core community. Here, we use internal isochrones, identified from airborne radar coupled to ice-flow modelling to estimate the age of basal ice along transects in the Dome C area. Three glaciological properties are inferred from isochrones: surface accumulation rate, geothermal flux and the exponent of the Lliboutry velocity profile. We find that old ice (>1.5 Myr, 1.5 million years) likely exists in two regions: one ~40 km south-west of Dome C along the ice divide to Vostok, close to a secondary dome that we name "Little Dome C" (LDC), and a second region named "North Patch" (NP) located 10-30 km north-east of Dome C, in a region where the geothermal flux is apparently relatively low. Our work demonstrates the value of combining radar observations with ice flow modelling to accurately represent the true nature of ice flow, and understand the formation of ice-sheet architecture, in the centre of large ice sheets. [ABSTRACT FROM AUTHOR]

Data acquired by monitoring modern biogeochemical cycles in tundra ecosystems in zones impacted by facilities of the gas industry indicate the absence of any perceptible changes in the system surface water-bottom sediments-soil-plants and show that the emitted nitrogen oxides beneficially affect productivity of the lichens and the functioning of the tundra ecosystem as a whole. [ABSTRACT FROM AUTHOR]

This study presents projections of twenty-first century wintertime surface temperature changes over the high-latitude regions based on the third Coupled Model Inter-comparison Project (CMIP3) multi-model ensemble. The state-dependence of the climate change response on the present day mean state is captured using a simple yet robust ensemble linear regression model. The ensemble regression approach gives different and more precise estimated mean responses compared to the ensemble mean approach. Over the Arctic in January, ensemble regression gives less warming than the ensemble mean along the boundary between sea ice and open ocean (sea ice edge). Most notably, the results show 3 °C less warming over the Barents Sea (~7 °C compared to ~10 °C). In addition, the ensemble regression method gives projections that are 30 % more precise over the Sea of Okhostk, Bering Sea and Labrador Sea. For the Antarctic in winter (July) the ensemble regression method gives 2 °C more warming over the Southern Ocean close to the Greenwich Meridian (~7 °C compared to ~5 °C). Projection uncertainty was almost half that of the ensemble mean uncertainty over the Southern Ocean between 30° W to 90° E and 30 % less over the northern Antarctic Peninsula. The ensemble regression model avoids the need for explicit ad hoc weighting of models and exploits the whole ensemble to objectively identify overly influential outlier models. Bootstrap resampling shows that maximum precision over the Southern Ocean can be obtained with ensembles having as few as only six climate models. [ABSTRACT FROM AUTHOR]

The ocean and sea ice in both polar regions are important reservoirs of freshwater within the climate system. While the response of these reservoirs to future climate change has been studied intensively, the sensitivity of the polar freshwater balance to natural forcing variations during preindustrial times has received less attention. Using an ensemble of transient simulations from 1500 to 2100 AD we put present-day and future states of the polar freshwater balance in the context of low frequency variability of the past five centuries. This is done by focusing on different multi-decadal periods of characteristic external forcing. In the Arctic, freshwater is shifted from the ocean to sea ice during the Maunder Minimum while the total amount of freshwater within the Arctic domain remains unchanged. In contrast, the subsequent Dalton Minimum does not leave an imprint on the slow-reacting reservoirs of the ocean and sea ice, but triggers a drop in the import of freshwater through the atmosphere. During the twentieth and twenty-first century the build-up of freshwater in the Arctic Ocean leads to a strengthening of the liquid export. The Arctic freshwater balance is shifted towards being a large source of freshwater to the North Atlantic ocean. The Antarctic freshwater cycle, on the other hand, appears to be insensitive to preindustrial variations in external forcing. In line with the rising temperature during the industrial era the freshwater budget becomes increasingly unbalanced and strengthens the high latitude's Southern Ocean as a source of liquid freshwater to lower latitude oceans. [ABSTRACT FROM AUTHOR]

Evidence is presented supporting the hypothesis of polar synchronization, which states that during the last ice age, and likely in earlier times, millennial-scale temperature changes of the north and south Polar Regions were coupled and synchronized. The term synchronization as used here describes how two or more coupled nonlinear oscillators adjust their (initially different) natural rhythms to a common frequency and constant relative phase. In the case of the Polar Regions heat and mass transfer through the intervening ocean and atmosphere provided the coupling. As working hypothesis, polar synchronization brings new insights into the dynamic processes that link Greenland's Dansgaard-Oeschger (DO) abrupt temperature fluctuations to Antarctic temperature variability. It is shown that, consistent with the presence of polar synchronization, the time series of the most representative abrupt climate events of the last glaciation recorded in Greenland and Antarctica can be transformed into one another by a π/2 phase shift, with Antarctica temperature variations leading Greenland's. This, plus the fact that remarkable close simulations of the time series are obtained with a model consisting of a few nonlinear differential equations suggest the intriguing possibility that there are simple rules governing the complex behavior of global paleoclimate. [ABSTRACT FROM AUTHOR]

Abstract: Self-Organizing Maps (SOMs) provide a powerful, nonlinear technique to optimally summarize complex geophysical datasets using a user-selected number of “icons” or SOM states, allowing rapid identification of preferred patterns, predictability of transitions, rates of transitions, and hysteresis/asymmetry in cycles. For example, SOM-based patterns concisely capture the spatial and temporal variability in atmospheric circulation datasets. SOMs and the SOM-based methodology are reviewed here at a practical level so as to encourage more-widespread usage of this powerful technique in the atmospheric sciences. Usage is introduced with a simple Antarctic ice core-based dataset to show analysis of multiple variables at a single point in space. Subsequent examples utilize a 24-year dataset (1979–2002) of daily Antarctic meteorological variables and demonstrate usage with 2-D, gridded data, for single and multiple variable scenarios. These examples readily show how SOMs capture nonlinearity in time series data, concisely summarize voluminous spatial data, and help us understand spatial and temporal change through, for example, pattern frequency analysis and identification of preferred pattern transitions. [Copyright &y& Elsevier]

Based on daily data from the Japanese 55-year Reanalysis (JRA-55) for the extended winters (December-March) from 1958/59 to 2014/15, this study examines the formation features and climate impacts of the Scandinavian (SCA) pattern on subseasonal timescale. Results show that the SCA can form with or without convective events over the Gulf Stream extension region. It turns out that in the North Atlantic sector, the convection-preceded SCA patterns show a larger amplitude and longer lifespan compared to the convection-free SCA patterns. The results also indicate that in addition to the forcing of convection over the Gulf Stream extension region, the driving of divergence associated with convective heating over the northern North Atlantic region, as well as the high-frequency eddies, may also contribute to the growth and rapid development of the SCA pattern. Another attracting feature observed in the formation processes of the SCA pattern is its downstream development, i.e., without apparent propagation of the individual anomalous centers of the SCA pattern, new anomalous centers continue to form downstream of the wavetrain, which lead to the formation of other kinds of teleconnection pattern over the western Pacific. Furthermore, vertical propagation of the SCA pattern from the troposphere into the stratosphere is also observed as the SCA pattern matures and decays. As a result of the propagation, the enhancement or weakening of the stratospheric polar vortex tends to occur. This suggests that the SCA pattern may bring about significant influence on both the surface weather/climate over the Arctic-Eurasia sector as well as the climate in the polar region of the stratosphere. [ABSTRACT FROM AUTHOR]

The mid-Pleistocene Transition is characterized by crucial changes in the frequency, amplitude, and symmetry of glacial-interglacial climate changes. Sediments of Lake El'gygytgyn in Far East Russia offer unique insights into the continental climate dynamics across the MPT and can provide constraints on the evolution of Arctic polar climate. Here we reconstruct climate variability from 3 Ma to present at El'gygytgyn, resolved at approximately 2000 year sample spacing, using glycerol dialkyl glycerol tetrather biomarkers (GDGTs). Utilization of a new HPLC method that separates GDGT isomers improves the paleoclimate interpretation and provides new insights on the MPT in the terrestrial Arctic. The distributions of branched GDGTs reflect changes in growing season temperature. Isoprenoid GDGT distributions likely record past occurrences of perennial ice cover and associated lake anoxia and are in general agreement with other sedimentary indicators of lake anoxia. We discuss changes in the amplitude and frequency of orbital-scale temperature changes from before and after the MPT, as well as changes in the occurrence of super-interglacial events. [ABSTRACT FROM AUTHOR]