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The Qinghai–Tibetan Plateau and Arctic both have an important influence on global climate, but the correlation between climate variations in these two regions remains unclear. Here we reconstructed and compared the summer temperature anomalies over the past 1,120 yr (900–2019 CE) in the Qinghai–Tibetan Plateau and Arctic. The temperature correlation during the past millennium in these two regions has a distinct centennial variation caused by volcanic eruptions. Furthermore, the abrupt weak-to-strong transition in the temperature correlation during the sixteenth century could be analogous to this type of transition during the Modern Warm Period. The former was forced by volcanic eruptions, while the latter was controlled by changes in greenhouse gases. This implies that anthropogenic, as opposed to natural, forcing has acted to amplify the teleconnection between the Qinghai–Tibetan Plateau and Arctic during the Modern Warm Period.

This study reports on the measurements of ion and refractory black carbon (rBC) concentrations in a shallow (10.96 m) ice core sample which was drilled from the field site of the East Greenland Ice Core Project (EGRIP) in July, 2016. The results provide a recent record of rBC deposition in the East Greenland ice sheet from 1990 to 2016. The annual variability in oxygen (δ18O) and hydrogen (δD) isotopic compositions indicated that notably warm events occurred since 2008. Peaks in rBC occurred during summer seasons, which may be attributed to the burning of biomass in boreal summer. The rBC record and analysis of historical air trajectories using the HYSPLIT model indicated that anthropogenic BC emissions from Russia, North America and Europe contributed to the majority of rBC deposition in the Greenland region, and a reduction in anthropogenic BC consumption in these areas played a dominant role in the decrease in BC concentrations since 2000. This record also suggests that the emissions from the East Asian region (China) contributed very little to the recorded BC concentrations in East Greenland ice core. The model results indicated that radiative forcing due to BC had decreased significantly since 1990, and had remained below 0.02 W m−2 since 2000.

The variation in the precipitation phase in polar regions represents an important indicator of climate change and variability. We studied the precipitation phase at the Great Wall Station and Antarctic Peninsula (AP) region, based on daily precipitation, synoptic records and ERA-Interim data during the austral summers of 1985−2014. Overall, there was no trend in the total precipitation amount or days, but the phase of summer precipitation (rainfall days versus snowfall days) showed opposite trends before and after 2001 at the AP. The total summer rain days/snow days increased/decreased during 1985−2001 and significantly decreased at a rate of −14.13 d (10 yr)−1/increased at a rate of 14.31 d (10 yr)−1 during 2001−2014, agreeing well with corresponding variations in the surface air temperature. Further, we found that the longitudinal location of the Amundsen Sea low (ASL) should account for the change in the precipitation phase since 2001, as it has shown a westward drift after 2001 [−41.1° (10 yr)−1], leading to stronger cold southerly winds, colder water vapor flux, and more snow over the AP region during summertime. This study points out a supplementary factor for the climate variation on the AP.

In Tarim River Basin (TRB), the retreat of glacier and snow cover reduction due to climate warming threatens the regional economy of downstream basins that critically depends on meltwater. However, the quantitative evaluation of its impact on multiple sectors of the socioeconomic system is incomplete. Based on compiled regional input–output table of the year 2012, this study developed a method to analyze the relationships between economic activities and related meltwater withdrawal, as well as sectoral transfer. The results show that the direct meltwater withdrawal intensity (DMWI) of agriculture was much higher than other sectors, reaching 2348.02 m3/10,000 CNY. Except for A01 (agriculture) and A02 (mining and washing of coal), the embodied meltwater withdrawal (EMW) driven by the final demand of other sectors was greater than direct meltwater withdrawal, and all sectors required inflows of virtual water (72.45 × 108 m3, accounting for 29% of total supply from cryospheric water resources) for their production processes in 2012. For sectors with high DMWI, improving water-use efficiency is an effective way to reduce water withdrawal. To some extent, the unbalanced supply of cryospheric water resources due to geographical segregation can be regulated by virtual water flows from water-saving to water-intensive sectors. Such decisions can affect the balance between socioeconomic development and environment conservation for long-term sustainability.

To differentiate the source of aeolian dust between the desert sources from Pan-third pole and high mountain glaciers, therefore, we investigated the spatial variability of aeolian dust sources in the Pan-third polar region. The question of whether such changes reflect variable transport pathways from a unique source in the western China area was addressed. That is, the SrNd radiogenic isotope composition of modern desert samples do not support the hypothesis of a single dust provenance at higher elevation mountain glaciers by long-distance transport; regional sources also play a significant role. Based on previous studies and the data from this study, the five isotopic regions were divided, which are controlled by the geological characteristics in western China. The results suggest that mineral dust deposited into the high-mountain glaciers originated from the free ice region because of glacier melting and the physical and chemical erosion of rocks from the surrounding mountains by local wind systems. The Pb isotopic data further demonstrated that natural dust is the source of Pb for the high-mountain glaciers of Pan-third pole. These results provide an exhaustive documentation of the isotopic signature of the regional dust reaching the glacier regions.

Iron concentrations in the Southern Ocean are thought to act as a driver of the regular glacial–interglacial cycles in atmospheric carbon dioxide (CO2). This study presents the concentrations of bioavailable Fe (dissolved Fe (DFe) and total dissolved Fe (TDFe)), major ions (Na+, K+, Mg2+, Ca2+, Cl−,NO3‐,SO42‐ and methanesulfonic acid (MSA)), heavy metal elements (Sr, Pb, V, Ti and Cd), and rare earth elements (REEs; specifically, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and the oxygen and hydrogen isotopic compositions (δ18O and δD) from a series of surface snow samples collected during from January 22 to February 5, 2017 along a traverse from Zhongshan Station to Dome A in East Antarctica. The results reflect the Antarctic surface snow Fe and the other trace element concentrations on the East Antarctica ice sheet. In particular, the DFe and TDFe concentrations were measured using inductively coupled plasma sector field mass spectrometry (SF-ICP-MS). The concentration patterns of DFe and TDFe show three different stages along this transect. First, there is an abrupt decrease with distance inland from the coast and then a slight decreasing trend with increasing elevation. The maximum concentrations were observed at distances of 450–600 km from the coast, indicating that there are different potential sources and/or transporting air masses. The variations show that the sources and processes that deliver bioavailable Fe differ along this transect. These data are useful for assessing bioavailable Fe release from the Antarctic ice sheet.

Snow cover provides essential resources and services for human well-being and socioeconomic development in arid areas. With the change in snow cover resulting from climate change that causes concerns about its consequences, there is a pressing need to analyze and understand its impact on the benefits that people has been enjoying from snow cover. These can be derived from the variation in economic value of snow services, that are demanded to meet socioeconomic activities. Based on the average decline mass of snow cover from 1979 to 2016 in Irtysh River Basin, we use the approach by applying economic evaluation to estimate the annual value loss of snow services. Considering the decreasing trend of snow cover mass at rates of −10.2 Mt per year (p

Earth system models (ESMs) consist of parameterization schemes based on one’s perception of how the Earth system functions. A typical ESM contains a large number of parameters (i.e., the constants and exponents in the parameterization schemes) whose specification can have a significant impact on an ESM’s simulation capabilities. Sensitivity analyses (SA) is an important tool for assessing how parameter specification influences model simulations. In this study, we used an Earth system model of intermediate complexity (EMIC)—LOVECLIM as an example to illustrate how SA methods can be used to identify the most sensitive parameters that control the simulations of several key global water and energy cycle variables, including global annual mean absolute surface air temperature (T G), precipitation and evaporation over the land and over the oceans (P L, P O, E L, E O), and land runoff (R L). We also demonstrate how judiciously specifying model parameters can improve the simulations of those variables. Three SA methods MARS, RF, and sparse PCE-based Sobol’ method were used to evaluate a pool of 25 adjustable parameters chosen from land, atmosphere, and ocean components of LOVECLIM and their results were intercompared to ensure robustness of the results. It is found that with different parameter specification, T G can vary from 10 to 20 °C, and the values of P L, P O, E L, and E O can change by more than 100%. An interesting observation is that the value of R L vary from 13,000 to 35,000 km3, far below the observed climatological value of 40,000 km3, indicating a model structural deficiency in representing land runoff by LOVECLIM which must be corrected to obtain more reasonable global water budgets. We also note that parameter sensitivities are significantly different at different latitudes. Finally, we showed that global water and energy cycle simulations can be significantly improved by even a crude automatic parameter tuning, indicating that parameter optimization can be a viable way to improve ESM climate simulations. The results from this study should help us to understand the parameter uncertainty of a full-scale ESM.

The degradation of the permafrost regions, resulting from intensive anthropogenic activities and global warming, has led to the loss of ecosystem services and is threating human well-being. Nevertheless, the real ecosystem service values and their complete zoning system in the permafrost regions have received insufficient attention. Research gaps between the identification of permafrost-based ecosystem services and ecosystem management are seriously constraining the development of cryospheric science. Thus, an ecosystem service zoning framework that links ecosystem services with human welfares is proposed to solve the abovementioned challenges in the permafrost regions of China. The three-tiered zoning framework for ecosystem services, consisting of zoning goals, principles, hierarchy, methodology, and nomenclature, is proposed for the permafrost regions of China. A combined method, i.e., GIS spatial tools, the location entropy analysis model, and ecosystem services assessment, was employed to distinguish ecosystem conditions, ecosystem service supply, and beneficiaries into these three-grade ecosystem service zones. Hierarchical and dynamic zoning could clarify protection priorities of ecosystems and ecosystem services in terms of regions, grades, and types. The framework could contribute to sustainable management of ecosystem services in the cryosphere. Keywords: Demand, Ecosystem services, Ecological zoning, Permafrost, Supply

The metal elements in alpine ice can provide historical information about natural mineral dust and anthropogenic pollutant emissions. To determine how the Fe concentration and flux variations relate to natural sandstorms and anthropogenic emissions from 1956 to 2004 A.D., Fe, Al, Pb and other element records were measured in a shallow ice core from the Miaoergou Glacier in East Tienshan, central Asia. The results indicate that the dissolved Fe (DFe) and total dissolved Fe (TDFe) peaks are well correlated with sandstorms from the surrounding Taklamakan Desert since at least 1956 A.D. The concentrations and fluxes of Pb show continuously increasing trends since 1995 A.D. due to the accelerating progress of the industrial revolution in China during this period, while the DFe and TDFe concentrations and the fractional Fe solubility exhibit no significant variations during this period. These results provide an ideal opportunity to investigate the effects of the natural Fe record in an arid region.

Perchlorate concentration in a shallow ice core at Tienshan, East Asia ranged between 0.55 and 52.1 ng L−1, with significant temporal variations during 1956–2004. Since the 1980s, a clear increasing trend of perchlorate was observed in the Miaoergou ice core, possibly the result of elevated stratospheric chlorine levels caused by emissions of anthropogenic volatile chlorine compounds. Although differences in trends and amounts were observed, the 1956–2004 perchlorate data from this study compares well with the perchlorate data from the High Arctic ice cores. The spatial and temporal differences of the perchlorate in Miaoergou ice core may be due to differences in anthropogenic sources. Such as, the nitrate ore field in Turpan-Hami Basin in eastern Xinjiang, China, may be the primary anthropogenic source. From the organic chlorine species emission data, HCFC-141b, HCFC-142b and HCFC-124 were identified as the primary anthropogenic sources responsible for the two perchlorate spikes observed for 1980–1996 and 1997–2001. The Miaoergou ice core covering the 1956–2004 period provides further evidence for the perchlorate deposition variations between mid-latitudes and the High Arctic regions.

The cryosphere is the part of the earth’s surface where the temperature is always below freezing. Since the 1970s, the frequency of rapid cryospheric change events has been increasing along with the significant rise of global temperature. This has or will lead to a series of cryospheric disasters with extreme damage. Disaster-formation mechanism, disaster-receptors, and environmental reactions to different types of disasters in the cryosphere have different spatial distribution patterns. The cryosphere can be divided into three major categories: Continental cryosphere, marine cryosphere, and aerial cryosphere. These depend mainly on its geographical distribution, dynamics, and thermodynamic conditions. Based on the results of past research, the present study systematically expounds the formation mechanism classification, spatial and temporal scales, and spatial differentiation of cryospheric disasters and reveals the comprehensive impact of global cryospheric disasters at high-risk areas and their trend. The results show the following. (1) Continental cryospheric disasters (e.g., avalanches, glacial lake outburst floods, freezing and thawing disasters, and glacier/snow flood/debris flow) are concentrated mainly in the Qinghai-Tibet Plateau, Siberia, Peruvian Andes, and northern North America and have already caused considerable risk to personal safety and damage to infrastructure. (2) Marine cryospheric disasters (sea ice disasters, coastal freeze-thaw erosion, and rises in sea level) occur mainly along coastal areas of the Arctic and the low-lying areas and island countries of the world. These disasters mainly affect navigation safety and ports, coastal/offshore facilities, and homeland security. (3) Aerial cryospheric disasters, especially snowstorms and rain and snow freezing disasters take place in the northeastern United States, Europe, East Asia, and China, mainly affecting transportation, aviation, and agriculture. Although the frequency of the cryospheric disaster is low, the scope and impact are very large. Cryospheric change, risk of cryospheric disaster, and the management thereof are closely related. It is urgently necessary to strengthen the understanding and assessment of the cryosphere change and its impact on the socio-economic system and integrated risk analysis. Specifically, we must adjust economic and social activities in areas at high risk of global cryospheric disasters and develop strategies for prevention and mitigation of cryospheric disasters and so reduce risk and improve resilience and sustainability.

We conducted a 2 m snow pit study in July 2017 at the East GRIP (Greenland Ice-Core Project; northeastern Greenland) deep ice-coring site. We collected snow samples at intervals of 0.05 m and analyzed their iron (Fe) and rare earth element (REE) concentrations. Pronounced seasonal variations in trace elements were observed during 2012–2017. The results indicated that the dissolved Fe (DFe), total dissolved Fe (TDFe), and total dissolved REEs (TDREEs) largely originated from mineral dust, which peaked in winter to early spring. In particular, the 2014–2015 Holuhraun eruption (31 August 2014 to 27 February 2015) can be clearly observed in the data at a depth of 90–125 cm. This event not only provided abundant acidic material (sulphate), but also released a large amount of DFe. Therefore, these results provide a possible way to use Greenland deep ice core data to construct a much longer history and better understand the relationship between eruptions and the release of iron in future studies.

Nine density-dependent empirical thermal conductivity relationships for firn were compared against data from three Automatic Weather Stations at climatically-different East Antarctica sites (Dome A, Eagle and LGB69). The empirical relationships were validated using a vertical, one-dimensional thermal diffusion model and a phase-change based firn diffusivity estimation method. The best relationships for these East Antarctica sites were identified by comparing the modeled and observed firn temperature at the depth of 1 m and 3 m, and from the mean heat conductivities over two depth intervals (1–3 m and 3–10 m). Among the nine relationships, that proposed by Calonne et al. (2011) appears to have the best performance. This study provides useful reference for firn thermal conductivity parameterizations in land modeling or snow-air interaction studies on the Antarctica Ice Sheet.

The spatial glaciochemical variability of snow samples collected along a transect from Zhongshan Station to Lambert Glacier Basin 69 (LGB69) in Antarctica was investigated. Sea-salt ion concentrations exponentially decreased with increasing distance from the coast and/or altitude. The observed high sea-salt ion concentrations within 20.6 km of the coast may be related to preferential wet or dry deposition of sea-salt aerosols. Methanesulfonic acid (MSA), non-sea-salt sulfate (nssSO42−), and calcium (Ca2+) concentrations decreased along the transect. The mean MSA/nssSO42− value of the surface snow samples (0.34 ± 0.08) indicates that coastal sea areas are their likely source regions. The non-sea-salt Ca2+ (nssCa2+)/Ca2+ percentages of the surface snow and LGB69 snow pit samples reveal that continental dust is the primary Ca2+ source. The δD and δ18O values decreased from the coast inland. The variation of deuterium excess (d-excess) along the transect was stable and d-excess values in the two snow pit samples were low and similar, which indicates that the moisture source region between Zhongshan Station and LGB69 is a coastal sea area. These results reveal the spatial distribution patterns and sources of ions and stable isotopes, as well as factors that influence the deposition of ions and the composition of stable isotopes, which provide important insight for further studies of ice cores drilled in Antarctic coastal regions.

Rain-on-snow (ROS) events can accelerate the surface ablation of sea ice, thus greatly influencing the ice–albedo feedback. However, the variability of ROS events over the Arctic Ocean is poorly understood due to limited historical station data in this region. In this study early melt season ROS events were investigated based on four widely used reanalysis products (ERA-Interim, JRA-55, MERRA, and ERA5) in conjunction with available observations at Arctic coastal stations. The performance of the reanalysis products in representing the timing of ROS events and the phase change of precipitation was assessed. Our results show that ERA-Interim better represents the onset date of ROS events in spring, and ERA5 better represents the phase change of precipitation associated with ROS events. All reanalyses indicate that ROS event timing has shifted to earlier dates in recent decades (with maximum trends up to −4 to −6 d per decade in some regions in ERA-Interim) and that sea ice melt onset in the Pacific sector and most of the Eurasian marginal seas is correlated with this shift. There has been a clear transition from solid to liquid precipitation, leading to more ROS events in spring, although large discrepancies were found between different reanalysis products. In ERA5, the shift from solid to liquid precipitation phase during the early melt season has directly contributed to a reduction in spring snow depth on sea ice by more than −0.5 cm per decade averaged over the Arctic Ocean since 1980, with the largest contribution (about −2.0 cm per decade) in the Kara–Barents seas and Canadian Arctic Archipelago.

Mercury (Hg) is a globally spread trace metal due to its long atmospheric residence time. Yet, our understanding of atmospheric processes (e.g., redox reactions and deposition) driving Hg cycling is still limited, especially in polar regions. The Antarctic continent, by virtue of its remoteness, is the perfect location to investigate Hg atmospheric processes in the absence of significant local anthropogenic impact. Here, we present the first 2 year record (2016-2017) of total suspended particulate mercury (PHg) concentrations along with a year-round determination of an Hg stable isotopic composition in particles collected at Zhongshan Station (ZSS), eastern Antarctic coast. The mean PHg concentration is 21.8 ± 32.1 pg/m3, ranging from 0.9 to 195.6 pg/m3, and peaks in spring and summer. The negative mass-independent fractionation of odd Hg isotopes (odd-MIF, average -0.38 ± 0.12‰ for Δ199Hg) and the slope of Δ199Hg/Δ201Hg with 0.91 ± 0.12 suggest that the springtime isotope variation of PHg is likely caused by in situ photo-oxidation and reduction reactions. On the other hand, the increase of PHg concentrations and the observed odd-MIF values in summer are attributed to the transport by katabatic winds of divalent species derived from the oxidation of elemental Hg in the inland Antarctic Plateau.

Mineral dust can indirectly affect the climate by supplying bioavailable iron (Fe) to the ocean. Here, we present the records of dissolved Fe (DFe) and total Fe (TDFe) in North Greenland Eemian Ice Drilling (NEEM) ice core over the past 110 kyr BP. The Fe records are significantly negatively correlated with the carbon-dioxide (CO2) concentrations during cold periods. The results suggest that the changes in Fe fluxes over the past 110 kyr BP in the NEEM ice core are consistent with those in Chinese loess records because the mineral-dust distribution is controlled by the East Asian deserts. Furthermore, the variations in the dust input on a global scale are most likely driven by changes in solar radiation during the last glacial–interglacial cycle in response to Earth's orbital cycles. In the last glacial–interglacial cycle, the DFe/TDFe ratios were higher during the warm periods (following the post-Industrial Revolution and during the Holocene and last interglacial period) than during the main cold period (i.e. the last glacial maximum (LGM)), indicating that the aeolian input of iron and the iron fertilization effect on the oceans have a non-linear relationship during different periods. Although the burning of biomass aerosols has released large amounts of DFe since the Industrial Revolution, no significant responses are observed in the DFe and TDFe variations during this period, indicating that severe anthropogenic contamination has no significant effect on the DFe (TDFe) release in the NEEM ice core.

The stable oxygen isotope composition, major ions and isotopic compositions of strontium (Sr), neodymium (Nd) and lead (Pb) in insoluble dust from recent surface snow samples along the transect from the Zhongshan and Progress stations (located on the Amery Ice Shelf, East Antarctica) to Dome A (Summit, Antarctica) were analysed. No previous isotopic fingerprinting studies have been conducted for this transect. These data were used to document the dust provenances in Antarctica along the transect up to the highest site, Dome A, for the first time. The insoluble dust in snow samples along the coast displays an overall crust-line isotopic signature that is characterised by highly radiogenic 87Sr/86Sr values and less radiogenic 143Nd/144Nd values. These signatures are comparable with those of samples collected near the ice-free areas of the Zhongshan and Progress stations. Spatial differences are statistically significant along the transect, and the Sr, Nd and Pb isotope components in insoluble dust from two continuous snow samples at Dome A exhibit marked differences, indicating that additional dust reaches the East Antarctic Plateau. The isotopic characteristics of insoluble dust from this transect indicate that the long-distance natural dust and anthropogenic pollutants in these samples primarily originate from Australia.

Changes in the form of precipitation have a considerable impact on the Arctic cryosphere and ecological system by influencing the energy balance and surface runoff. In this study, station observations and ERA-Interim data were used to analyze changes in the rainfall to precipitation ratio (RPR) in northern Canada during the spring–summer season (March–July) from 1979–2015. Our results indicate that ERA-Interim describes the spring–summer variations and trends in temperature and the RPR well. Both the spring–summer mean temperature [0.4°C–1°C (10 yr)-1] and the RPR [2%–6% (10 yr)-1] increased significantly in the Canadian Arctic Archipelago from 1979–2015. Moreover, we suggest that, aside from the contribution of climate warming, the North Atlantic Oscillation is probably another key factor influencing temporal and spatial differences in the RPR over northern Canada.

Using high-resolution ice core and tree ring proxies for sea ice extent (SIE), we reconstructed a robust time series of autumn SIE over the Barents-Kara (B-K) sector of the Arctic from AD1289–1993. After intercomparing the results and statistical parameters using the ordinary least squares regression (OLSR), the principle component regression (PCR) and the partial least squares regression (PLSR) methods, SIE time series were synthesized into a more robust series using the weighted average method, which used the explained variances as weights. The results showed that from the end of the 13th century to the end of 18th century, the autumn B-K SIE was large, with large variations and a slightly expanding trend overall. This reflected significant multidecadal oscillations under the Little Ice Age (LIA) background. The B-K SIE began to decrease at the end of the 18th century, and a shrinking trend became significant during the second half of the 19th century, which lasted into the 1930s–1940s. The 1930s–1940s was a period with a relatively low SIE in the B-K Sea, and the SIE had a short period of expansion from the 1940s–1970s. However, the B-K SIE has continuously and significantly shrank since the 1970s. The reduction in the B-K SIE since the end of the 18th century has been unprecedented in both duration and speed over the last 700 years. The B-K SIE has retreated significantly since the 1970s, with a speed 6.18 times greater than the former mean retreating speed. The industrial revolution may be a dominant factor in this result. The Arctic SIE in recent years may be the lowest it has been over the last millennium.

The changes of precipitation form have important impacts on mass balance and energy flux of the underlying Cryosphere that closely related to hydrological cycles and the health of the ecosystem over the Arctic. So far, most of land stations around Arctic record the total precipitation amount only, except for dozens of stations in Alaska and northern Canada, where the solid and liquid precipitation are recorded respectively. Based on these different precipitation form records and daily mean air temperature observations during 1961–2015, we developed a special standard of optimum temperature threshold to separate rainfall from the total precipitation. That is, if the air temperature is greater than the temperature threshold, the probability of precipitation occurring as rain is larger than 0.5, then we assume the precipitation falls in liquid form. We derived the seasonal optimum temperature threshold of 2.01°C (spring), 0.54°C (summer), 1.14°C (fall) and 1.17°C (mean annual), respectively. We did not discuss the situation in winter because of rare liquid precipitation observations. By using these temperature thresholds, we distinguished the solid and liquid phase from total precipitation archived at 253 stations over the northern Eurasia region and investigated their variation trend during 1961–2010. Results showed that the proportion of rainfall in total precipitation decreased with latitudes in the region north of 60°N. In general, we found the maximum and minimum of the rainfall to total precipitation ratio (RPR) in summer and winter. Further analysis demonstrated that the precipitation forms showed obvious seasonal and interannual variability. Specially, the spring RPR increased over most of the terrestrial Arctic (82.46% stations), 22.37% of which passed 95% statistical significance test, indicating that there was a general transition trend from solid precipitation to liquid precipitation in the spring Arctic continents over the past decades. In summer and autumn, there was obvious regional variability in the south of the research area, but in the arctic coastal stations the increasing trend appeared uniform. The RPR trends, respectively derived from the lower and upper limits of 95% confidence interval of temperature threshold, were highly consistent with the trend in the spatial distribution that derived from the optimum temperature threshold. Additionally, more precipitation had fallen as rainfall instead of snowfall in Alaska, Siberia and Northern Europe during the ablation season (March-July), which would make profound impacts on the Arctic land-atmosphere interaction.

Based on the field measurements in Barrow, Alaska within the period of April–May 2015, we investigate the sources and variations of elemental carbon (EC) and organic carbon (OC) in the surface layer of snowpack on sea ice, and estimate their effects on the sea ice albedo. Results show that the snow OC in Barrow are from natural sources (e.g. terrestrial higher plants and micro-organisms) mainly, as well as biomass burning (e.g. forest fires and straw combustion) as an important part. Both EC and OC can accumulate at the snow surface with snow melt. The variations in EC and OC and liquid water content in the snow layer are well consistent during the snow-melting period. A higher rate of snow melt implied a more efficient enrichment of EC and OC. In the last phase of snow melt, the concentration increased to a maximum of 16.2 ng/g for EC and 128 ng/g for OC, which is ∼10 times larger than those before snow melt onset. Except for the dominant influence of melt amplification mechanism, the variation in concentrations of EC and OC could be disturbed by the air temperature fluctuation and snowfall. Our study indicates that the light-absorbing impurities contributed 1.6%–5.1% to the reduction in sea ice albedo with melt during the measurement period. The significant period of light-absorbing impurities influencing on sea ice albedo begins with the rapid melting of overlying snow and ends before the melt ponds formed widely, which lasted for about 10 days in Barrow, 2015.

A positive change in the southern annular mode (SAM), which is the primary pattern of climate variability in the Southern Hemisphere, has been induced predominantly by polar stratospheric ozone depletion. However, the lack of long-term observational records limits our understanding of the long-term SAM behaviour. In this study, we found that the geochemical record of the LGB69 ice core from the eastern coast of Antarctica was significantly correlated with the winter SAM index (SAMI). In addition, we developed an annual mean SAMI beginning in 1701 based on 15 annually resolved ice cores and relevant proxy–climate relationships. Our reconstruction accounted for 54.8% of the total variance from 1957 to 2000 (the calibration period). We demonstrate that the recent positive phase shift in the annual mean SAMI since the 1970s is unprecedented, with the estimate for the latest regime in the 1990s reaching values 2.5 times the standard deviation above the baseline (1701–2000). This peak value also coincides with the largest 30- and 50-year trends, which have occurred at the end of the 20th century. From the reconstructed SAMI, we also found that the response to large volcanic events was likely positive in the 3 years after the eruption, but this positive response can be masked by internal climate variability when a strong El Nino event occurs in the eruption year.

Cryospheric changes and their impacts have received increasing concern, extending the research to include the interactions between earth spheres and the impacts of and social adaptation to cryospheric changes. As a result, Cryospheric Science is rapidly developing. However, the research framework of Cryospheric Science has not completely been set up, and the intension and extension of Cryospheric Science are unclear. Following a literature review, the research framework for Cryospheric Science and the discipline components are analysed in this paper. We consider that Cryospheric Science is an inevitable product of international research on the earth and environmental changes as well as on human sustainable development. It will not only strengthen the linkage between the cryosphere and other earth spheres by deepening traditional research areas, but will also bring more focus on the critical roles of the cryosphere in interactions between earth spheres, and will enhance the relationship between cryospheric change and climate, ecology, hydrology, surface environment and sustainable development. The disciplinary tree of Cryospheric Science is developed following the mainstream of change-impacts adaptation. The disciplines of Cryospheric Science were teased out against characteristics of traditional branches and the developing interdisciplinary branches of cryosphere elements, which will provide reference to Cryospheric Science as it systematically grows to maturity.

A high-frequency and precise ultrasonic sounder was used to monitor precipitated/deposited and drift snow events over a 3-year period (17 January 2005 to 4 January 2008) at the Eagle automatic weather station site, inland Antarctica. Ion species and oxygen isotope ratios were also generated from a snow pit below the sensor. These accumulation and snowdrift events were used to examine the synchronism with seasonal variations of δ18O and ion species, providing an opportunity to assess the snowdrift effect in typical Antarctic inland conditions. There were up to 1-year differences for this 3-year-long snow pit between the traditional dating method and ultrasonic records. This difference implies that in areas with low accumulation or high wind, the snowdrift effect can induce abnormal disturbances on snow deposition. The snowdrift effect should be seriously taken into account for high-resolution dating of ice cores and estimation of surface mass balance, especially when the morphology of most Antarctic inland areas is similar to that of the Eagle site.

The compositions of Sr and Pb isotopes in the soluble and insoluble dust in six samples from the Miaoergou ice core in eastern Tienshan, China, were measured. The six samples were dated from top to bottom as follows: 2000 AD, 1991 AD, 1983 AD, 1977 AD, 1962 AD and 1958 AD. The 87Sr/86Sr ratios in the soluble fraction ranged from 0.709984 to 0.711031. The isotopic ratios of Pb in the soluble and insoluble dust were between 17.962–18.182 and 18.198–18.409 for 206Pb/207Pb; 15.540–15.606 and 15.560–15.581 for 208Pb/207Pb; and 37.994–38.173 and 38.179–38.384 for 208Pb/204Pb, respectively. These isotopic results for insoluble dust allowed us to document the origins of the dust in the Miaoergou Glacier in eastern Tienshan. The major sources of the natural aeolian deposits were the Taklamakan and Gobi deserts. Natural and anthropogenic Pb sources were assessed using a simple ternary model in which deserts, lead ore and coal served as the primary sources of insoluble dust. Lead ore, coal combustion, and the use of leaded gasoline in the surrounding area may represent additional anthropogenic sources of soluble dust. Thus, anthropogenic sources could be further investigated by using the dust-free soluble fractions. The Pb concentration and Pb isotopic compositions from the High Asia ice cores provided distinct evidence of the positive influences of anthropogenic factors associated with industrial development and the prevailing atmospheric circulation patterns in these regions.

We report the first high-resolution record of arsenic (As) observed in Greenland snow and ice for the periods 1711-1970 and 2003-2009 AD. The results show well-defined large-scale atmospheric pollution by this toxic element in the northern hemisphere, beginning as early as the 18th century. The most striking feature is an abrupt, unprecedented enrichment factor (EF) peak in the late 1890s, with an ∼30-fold increase in the mean value above the Holocene natural level. Highly enriched As was evident until the late 1910s; a sharp decline was observed after the First World War, reaching a minimum in the early 1930s during the Great Depression. A subsequent increase lasted until the mid-1950s, before decreasing again. Comparisons between the observed variations and Cu smelting data indicate that Cu smelting in Europe and North America was the likely source of early anthropogenic As in Greenland. Despite a significant reduction of ∼80% in concentration and ∼60% in EF from the 1950s to the 2000s, more than 80% of present-day As in Greenland is of anthropogenic origin, probably due to increasing As emissions from coal combustion in China. This highlights the demand for the implementation of national and international environmental regulations to further reduce As emissions.

The development of ski areas would bring socio-economic benefits to mountain regions. At present, the ski industry in China is developing rapidly, and the number of ski areas is increasing dramatically. However, the understanding of the spatial pattern and driving factors for these ski areas is limited. This study collected detailed data about ski areas and their surrounding natural and economic factors in China. Criteria for classification of ski areas were proposed, and a total of 589 alpine ski areas in China were classified into three types: ski resorts for vacationing (va-ski resorts), ski areas for learning (le-ski areas) and ski parks to experience skiing (ex-ski parks), with proportions of 2.1%, 15.4% and 82.5%, respectively, which indicated that the Chinese ski industry was still dominated by small-sized ski areas. The overall spatial patterns of ski areas were clustered with a nearest neighbor indicator (NNI) of 0.424, in which ex-ski parks and le-ski areas exhibited clustered distributions with NNIs of 0.44 and 0.51, respectively, and va-ski resorts were randomly distributed with an NNI of 1.04. The theory and method of spatial autocorrelation were first used to analyze the spatial pattern and driving factors of ski areas. The results showed that ski areas in cities had a positive spatial autocorrelation with a Moran&rsquo, s index value of 0.25. The results of Local Indications of Spatial Association (LISA) showed that ski areas were mainly concentrated in 3 regions: the Beijing-centered Yanshan-Taihang Mountains and Shandong Hill areas, the Harbin-centered Changbai Mountain areas and the Urumqi-centered Tianshan-Altay Mountain areas. The first location was mainly driven by socio-economic factors, and the latter two locations were mainly driven by natural factors. Ski tourism in China still faces many challenges. The government sector should strengthen supervision, develop a ski industry alliance, and promote the healthy and sustainable development of the ski industry in the future.

Polar ice sheets conserve atmospheric mineral dust (aerosols) at the time of snowfall, and this material can be used to reconstruct historical climate and environmental conditions. Snowpit samples were obtained from the East Greenland Ice Core Project (EGRIP) site in July 2017. Mineral dust concentrations as well as stable water isotope (δ18O, δD, and deuterium excess) and major ion (F−, Cl−, $${\text{NO}}_{2}^{-}$$ , $${\text{NO}}_{3}^{-}$$ , $${\text{SO}}_{4}^{2-}$$ , methanesulfonic acid (MSA), Na+, $${\text{NH}}_{\text{4}}^{\text{+}}$$ , Mg2+ and Ca2+) concentrations were analyzed in this study. The seasonal δ18O and δD cycles indicate that the snowpit samples covered the period from winter 2012 to summer 2017. The concentrations of mineral dust and Ca2+ showed seasonal deposition events with maxima in the spring layers. The concentrations of MSA exhibited maxima in the summer layers, making them useful indicators for the summer season. Moreover, an anomalous non-sea salt $${\text{SO}}_{4}^{2-}$$ (nss $${\text{SO}}_{4}^{2-}$$ ) event was recorded at a depth of 130 − 85 cm that corresponded to the Holuhraun eruption (31 August 2014). In addition, a significant short-term cooling effect was observed. A back-trajectory analysis suggests that a major ash event from Iceland contributed to the Greenland ice sheet (GrIS). These results provide insight for future studies of the EGRIP ice core.

Cryosphere services (CSs) refer to various benefits that humans directly or indirectly obtain from the cryosphere, which makes significant contributions to human well-being (HWB). To facilitate such research, we first present a classification system for conceptualizing, monitoring and assessing CSs based on the current process-based understanding of their nature and sustainability. Specifically, the CSs are grouped into five major categories (provisioning, regulating, cultural, bearing and supporting services) and 18 sub-categories. Then we provide a detailed overview on formation, current status and anticipated future changes of the identified types of the services, and their impact on HWB. Finally, the spatio-temporal scales, the links of the services with HWB and climate-dependence are further discussed. The research of CSs adopt interdisciplinary approach to address the formation mechanisms of CSs and their dynamic relationships with HWB, which is poised to provide a better understanding of the cryosphere’s role in human society and help enhance socio-ecological sustainability and HWB over cryosphere-affected areas. Notably, most CSs have been deteriorating under global warming and cryosphere shrinkage, further leading to negative impacts on associated HWB. Therefore, great attention should be paid to the changes in CSs and their cascading risks.

Iron is thought to limit the biomass of phytoplankton populations in extensive regions of the ocean, which are referred to as high-nutrient low-chlorophyll (HNLC) regions. Iron speciation in soils is still poorly understood. We have investigated inorganic and organic standard substances, diluted mixtures of common Fe minerals in insoluble dust in snow from the Laohugou No.12 glacier, and sand (including soil and moraine) samples that were collected from western China. The speciation of iron (Fe) in insoluble dust and sand was determined by X-ray absorption near-edge structure (XANES) spectroscopy. A linear fit combination (LCF) analysis of the experimental spectra compared to a large set of reference compounds showed that all spectra can be fitted by only four species: Fe2O3, Fe3O4, biotite, and ferrous oxalate dihydrate (FOD). A significant altitude effect was detected for snow. The proportion of Fe2O3 in snow decreases gradually, and vice versa for FOD. As for Fe3O4 and biotite, the altitude effect was also detected, but separate regions should be considered to be deduced by topography. The Fe species in moraines and soils were also analyzed to identify the source of moraines and the heterogeneity of soils, and were compared with snow.

Decline in snow mass threatens the regional economy that critically depends on meltwater. However, the economic scale of snow mass loss is hardly understood, and its role in the vulnerability of future economic development is unclear. We investigate the current reserves of snow cover and the value of its loss. The result showed that the total annual snow mass in western China declines at a rate of 3.3 × 109 Pg per decade (p < 0.05), which accounts for approximately 0.46% of the mean of annual snow mass (7.2 × 1011 Pg). Snow mass loss over the past 40 years in western China turns into an average loss value of CN¥0.1 billion (in the present value) every year ($1 = CN¥7). If the trend continues at the current rate, the accumulated loss value would rise to CN¥63 billion by 2040. Furthermore, subject to the combinations of RCPs and SSPs scenario, the future economic value of snow mass loss in western China appears to accelerate driven by both declining snowmelt resources and socioeconomic development demand. RCP26-SSP1 is the pathway among all to have the least economic cost in replacing the snowmelt loss, and the cost would be quadrupled in RCP80-SSP3 scenario by 2100. At a basin scale, the declining snow mass would turn the regional economy to be more vulnerable except Junggar and Ili endorheic basin. The Ertis river and Qaidam endorheic basins display to be most vulnerable. It highlights that the snow value can be economically important in the regions of west China and should be considered more properly in water resources management.

Refractory black carbon (rBC) aerosols emitted by biomass burning and fossil fuel combustion can cause significant climatic forcing when it deposited on the snow. The Southern Hemisphere (SH) biomass burning emissions represent a significant part of rBC in and around Antarctica. Here we present the spatial and temporal variations of rBC from the surface snow and snow pits samples along the coastal Zhongshan Station (ZSS) to inland Dome A transect in Lambert Glacier region of eastern Antarctica. The geometric mean concentrations of surface snow rBC was 0.017 ± 0.018 ng g−1 and showed higher values in the inland plateau region (900–1248 km, 0.031 ± 0.024 ng g−1) than the coastal region (0–400 km, 0.011 ± 0.005 ng g−1) and there exist similar spatial results for the inland snowpit (0.021 ± 0.017 ng g−1) and coastal snowpit (0.018 ± 0.013 ng g−1). The records from the coastal snowpit (SP-A) show that the rBC from 2009 to 2016 displays weak seasonal variations, while in the inland snowpit (SP–C) the records spans from 1950 to 2015 and showed the rBC concentrations vary and relate with the open biomass burning emission in the Southern Hemisphere.

Based on daily minimum, maximum, and mean surface air temperatures (Tmin, Tmax, Tmean) from the European Centre for Medium-Range Weather Forecast's reanalysis from 1979 onwards (ERA Interim), the accuracy of daily Tmin and Tmax reanalysis is assessed against in situ observations from four automatic weather stations (Zhongshan, EAGLE, LGB69, and Dome A) in East Antarctica from 2005 to 2008. ERA Interim generally shows a warm bias for Tmin and a cool bias for Tmax, with an underestimation of the diurnal temperature range. The reanalysis explains more than 84% of the daily and annual variance, and the replicating ability decreases gradually from the coast to the interior, with annual root mean square errors of 2.4 °C, 2.6 °C, 3.0 °C, and 4.3 °C for daily Tmin, and 2.2 °C, 3.1 °C, 3.4 °C, and 4.9 °C for daily Tmax at Zhongshan, LGB69, Eagle, and Dome A, respectively. ERA Interim shows little seasonal variability, although it performs a little better in the austral spring and worse in winter and autum...

The spatiotemporal distribution pattern of marine-origin matter on the Antarctica ice sheet was used to study variations in the source regions, transport mechanisms and post-depositional influences. We present data on sea salt ions, sulfur components and stable isotopes from surface and snow pit samples collected along the transect route from Zhongshan Station to Dome A during the austral summer in 2012–2013. A general decreasing trend in the accumulation, sea salt ions and sulfur components occurred with increasing distance from the coast and increasing elevation. However, different sources of the marine components, transport pathways and post-depositional influences were responsible for their different spatial distribution patterns. The marine ions in the coastal snow pit varied seasonally, with higher sea salt ion concentrations in the winter and lower concentrations in the summer; the opposite pattern was found for the sulfur compounds. The sea ice area surrounding Antarctica was the main source region for the deposited sea salt and the open sea water for the sulfur compounds. No significant trends in the marine-origin components were detected during the past 3 decades. Several periods of elevated deposition of sea salt ions were associated with lower temperatures (based on δD and δ 18 O) or intensified wind fields. In comparison to the sea salt ions, the sulfur concentrations exhibited the opposite distribution patterns and were associated with changes in the surrounding sea ice extent.

Understanding the dynamics of glaciers is essential for the knowledge of global sea-level rise, local freshwater resources in high mountain and arid regions, and the potential glacial hazards. In this paper, we present a two-dimensional thermomechanically coupled ice flow model named PoLIM (Polythermal Land Ice Model). The velocity solver of PoLIM is developed based on the Blatter–Pattyn approximation of Stokes flow. It uses an enthalpy formulation of the energy balance, an approach that is suitable for modeling the polythermal glaciers. PoLIM also includes a scheme for gravity-driven drainage of water in temperate ice, a subglacial hydrology model coupled with ice dynamics, and multiple basal sliding laws. The model has been verified by standard benchmark problems, including the ISMIP-HOM experiments, the enthalpy benchmark experiments, and the SHMIP experiments. PoLIM shows good performances and agrees well with these benchmark results, indicating its robust capability of simulating the thermomechanical behaviors of glaciers.

In this study, a shallow ice core (12.5 m, called LGB) was drilled at the Lambert Glacial Basin, East Antarctica. The major ion and metal elements were measured at 5–6 cm resolution in this shallow core, which covered the period 1990–2017. Therefore, an annual-resolution record of iron (Fe) concentrations and fluxes were reconstructed in this shallow ice core. Although the Fe data is comparable to previous results, our results emphasized that much more dissolved Fe (DFe) from the Cerro Hudson volcanic event (August 1991) was transported to the East Antarctic ice sheet, in comparison with the Pinatubo volcanic event (June 1991). The aeolian dust may be the primary DFe source during 1990–2017. In particular, the DFe variations may be affected by the biomass burning emissions in two periods (1990–1998 and 2014–2017). While total dissolved Fe (TDFe) variations were controlled by the climatic conditions since 2000 because of the temperature (δ18O) decreasing at East Antarctica. These Fe data will be useful to assess the modern bioavailable Fe release for the Antarctica ice sheet.

The differing response of ice extent in the Arctic and Antarctic to global average temperature change, over approximately the last three decades, highlights the importance of reconstructing long-term sea-ice history. Here, using high-resolution ice-core records of methane-sulfonate (MS–) from the East Antarctic ice sheet in Princess Elizabeth Land, we reconstruct southern Indian Ocean sea-ice extent (SIE) for the sector 62–92° E for the period AD 1708–2000. Annual MS– concentration positively correlates in this sector with satellite-derived SIE for the period 1979–2000 (r2 = 0.25, P < 0.02). The 293 year MS– record of proxy SIE shows multi-decadal variations, with large decreases occurring in two warm intervals during the Little Ice Age, and during the 1940s. It is very likely that the global temperature is the controlling factor of Antarctic sea-ice variation at the centennial scale, although there has been a change in phase between them in recent decades.

冰川内部所含的水分对冰的物理性质有很大的影响。应用探地雷达探测技术,我们首次对雅鲁藏布江源头杰玛央宗冰川积累区上部冰底的热学状况进行了调查。使用共偏移距法和共中点法,我们分析了相对于冷暖冰交界面和冰岩界面的探地雷达波速(分别为0.1751 ± 0.0028 m ns−1和0.1657 ± 0.0033 m ns−1)。结果表明,在探测地点的冰川底部存在一定厚度(16.6 ± 1.8 m)的暖冰层。根据暖冰层中的探地雷达波速(0.1410 ± 0.0154 m ns−1),我们推测含水量约为6 % ± 4 %,因而推测目前杰玛央宗冰川可能为多温型冰川。

The accuracy of daily mean surface pressure from five meteorological reanalyses is assessed against in situ observations from automatic weather stations in East Antarctica for 2005 to 2008. The in situ observations are from Zhongshan, LGB69, EAGLE, and Dome A. The five reanalyses all explain more than 87% of the average variance and have annual root mean square errors between 15 hPa and 45 hPa. The ERA Interim reanalysis performs best against both criteria. The NCEP-1, NCEP-2, and 20CRv2 reanalyses have negative biases of 29.7 hPa, 25.9 hPa, and 11.1 hPa, respectively, while ERA Interim and JCDAS have positive biases of 4.9 hPa and 14.9 hPa. The reanalyses do not show obvious seasonal differences. The errors generally tend to decrease from the coast to the interior of the East Antarctic ice sheet, although there are regional differences between the performance of the different reanalyses. ERA Interim is superior to other reanalyses, probably because of its 4D assimilation scheme, which is strongl...

To determine the potential sources of dust at high latitudes in the Northern Hemisphere, this study measured the stable isotopic ratios of strontium (Sr), neodymium (Nd) and lead (Pb) in insoluble dust in snow samples (as well as in soil and sand samples) from sites in northwestern China and high latitudes in the Northern Hemisphere: Altay (Xinjiang, China), Ny-Alesund (Svalbard), Barrow (Alaska) and the Arctic Ocean. The combined plots of the Sr–Nd–Pb isotopic data demonstrate that there are distinctive geographic patterns among the different sampling sites. The Sr–Nd results from the Altay (Xinjiang) and Ny-Alesund (Svalbard) sites display overall crust-like isotopic patterns, indicating that local mineral sources represent a significant contribution. The 87Sr/86Sr and eNd(0) data from the sea ice snow samples from the Arctic Ocean and snow samples from Barrow (Alaska) suggest potential long-range dust transport to the Arctic region. Our results indicate that Russia may be a source of anthropogenic pollutants for the high Arctic region, while North America may be a source of anthropogenic pollutants for Barrow, Alaska. These findings are beneficial for protecting the environment at the global scale.

The comprehensive understanding of the cryosphere’s global biogeochemical cycles represents a great challenge for the present climatic and environmental research on Earth [...]

Knowledge of present-day ice temperature and velocity is important in order to determine how fast a glacier will respond to present and future climate change. We apply a two-dimensional higher-order thermomechanical flowband model to simulate present-day ice temperature and velocity along the main flowline of East Rongbuk Glacier, Qomolangma (Mount Everest), Himalaya. We use recent (2005–11) observational data to validate the numerical model. Modelled and observed ice surface velocities exhibit good agreement. Modelled ice temperatures agree well with observed values in two shallow boreholes that are ∼18 m deep. The model suggests that the ablation zone of East Rongbuk Glacier, km 4 to km 10 from the glacier head, is underlain by temperate ice.

Land surface process studies over the Tibetan Plateau had made large achievements in the last three decades, focus mainly on: (1) Multi-sphere interactions in the Tibetan Plateau and their impacts on regional climate, hydrology and ecosystem. (2) Mechanisms and impacts of cryospheric hazards, including cold regions engineering. (3) tempo-spatial patterns of paleoenvironment. Achievement was also made in the changes of polar cryosphere and their influences to high/middle latitudinal climate. Future expectation includes enhancing the modeling work on cryosphere research, multi-discipline research considering multi-sphere interaction, and the potential new directions linked to social activities.

As an important part of the climate system, the cryosphere, can be studied with a variety of techniques based on laboratory-based or field-portable equipment in order to accumulate data for a better understanding of this portion of the Earth’s surface. The advent of synchrotron radiation (SR) facilities as large scientific interdisciplinary infrastructures has reshaped the scenario of these investigations and, in particular, of condensed matters researches. Many spectroscopic methods allow for characterizing the structure or electronic structure of samples, while the scattering/diffraction methods enable the determination of crystalline structures of either organic or inorganic systems. Moreover, imaging methods offer an unprecedented spatial resolution of samples, revealing their inner structure and morphology. In this contribution, we briefly introduce the SR facilities now available in mainland China, and the perspectives of SR-based methods suitable to investigate ice, snow, aerosols, dust, and other samples of cryospheric origin from deep ice cores, permafrost, filters, etc. The goal is to deepen the understanding in cryospheric sciences through an increased collaboration between the synchrotron radiation community and the scientists working in polar areas or involved in correlated environmental problems.

The Tienshan Urumqi Glacier No.1 (TUG1) usually shows "grey" surfaces in summers. Besides known regional warming, what should be responsible for largely reducing its surface albedo and making it look "grey"? A field campaign was conducted on the TUG1 on a selected cloud-free day of 2013 after a snow fall at night. Fresh and aged snow samples were collected in the field, and snow densities, grain sizes, and spectral reflectances were measured. Light-absorbing impurities (LAIs) including black carbon (BC) and dust, and number concentrations and sizes of the insoluble particles (IPs) in the samples were measured in the laboratory. High temperatures in summer probably enhanced the snow ageing. During the snow ageing process, the snow density varied from 243 to 458 kg m(-3), associated with the snow grain size varying from 290 to 2500 μm. The concentrations of LAIs in aged snow were significantly higher than those in fresh snow. Dust and BC varied from 16 ppm and 25 ppb in fresh snow to 1507 ppm and 1738 ppb in aged snow, respectively. Large albedo difference between the fresh and aged snow suggests a consequent forcing of 180 W m(-2). Simulations under scenarios show that snow ageing, BC, and dust were responsible for 44, 25, and 7 % of the albedo reduction in the accumulation zone, respectively.

Samples of surface snow were collected for stable isotope analysis along the traverse route from Zhongshan to Dome A (East Antarctica) from Dec 28th, 2007 to Feb. 8th, 2008. The local relationship between δD and surface temperature is established to be 6.4 ± 0.2 ‰ per °C, very similar to the average for East Antarctic. The deuterium excess shows a pattern of high values over Antarctica, particularly at Dome A. We compare our data with an atmospheric general circulation model which includes stable water isotopes (ECHAM5-wiso). The model simulation captures the right levels of δD, but overestimates δ18O. This study provides support for the ongoing deep ice core project at Dome A.

Black carbon concentrations in the snow collected from some selected glaciers in west China during 2004–2006 were measured. Higher concentrations appeared at lower sites, possibly due to the topography (e.g. altitude) effect. BC concentrations in snow of Tienshan Mountains outside the Tibetan Plateau (TP) were generally higher than those inside the TP, and strong melting in spring added on more regional/local emissions from the inner TP might both contribute higher concentrations for the central TP than those on the margin of the TP. Comparison between global measured BC concentrations in snow/ice suggested the distance of the sampling site away from strong BC-emitting areas (north mid-latitudes) could be responsible for BC concentrations in snow/ice. A rough estimate for the reduced albedos in some glaciers suggested BC deposited in the surface might accelerate the melt of these glaciers in west China, e.g. HXR48 and MEG3 which were strongly contaminated by BC in their surfaces, the reduced albedos were over 5% due to the BC deposits.

This paper reviews developments in our understanding of the state of the Antarctic and Southern Ocean climate, and its relation to the global climate system over the last few millennia. Climate over this and earlier periods has not been stable, as evidenced by the occurrence of abrupt changes in atmospheric circulation and temperature recorded in Antarctic ice core proxies for past climate. Two of the most prominent abrupt climate change events are characterized by intensification of the circumpolar westerlies (also known as the Southern Annular Mode) between ~6000 and 5000 years ago and since 1200-1000 years ago. Following the last of these is a period of major trans-Antarctic reorganization of atmospheric circulation and temperature between AD1700 and 1850. The two earlier Antarctic abrupt climate change events appear linked to but predate by several centuries even more abrupt climate change in the North Atlantic, and the end of the more recent event is coincident with reorganization of atmospheric circulation in the North Pacific. Improved understanding of such events and of the associations between abrupt climate change events recorded in both hemispheres is critical to predicting the impact and timing of future abrupt climate change events potentially forced by anthropogenic changes in greenhouse gases and aerosols. Special attention is given to the climate of the past 200 years, which was recorded by a network of recently available shallow firn cores, and to that of the past 50 years, which was monitored by the continuous instrumental record. Significant regional climate changes have taken place in the Antarctic during the past 50 years. Atmospheric temperatures have increased markedly over the Antarctic Peninsula, linked to nearby ocean warming and intensification of the circumpolar westerlies. Glaciers are retreating on the Peninsula, in Patagonia, on the sub-Antarctic islands, and in West Antarctica adjacent to the Peninsula. The penetration of marine air masses has become more pronounced over parts of West Antarctica. Above the surface, the Antarctic troposphere has warmed during winter while the stratosphere has cooled year-round. The upper kilometer of the circumpolar Southern Ocean has warmed, Antarctic Bottom Water across a wide sector off East Antarctica has freshened, and the densest bottom water in the Weddell Sea has warmed. In contrast to these regional climate changes, over most of Antarctica near-surface temperature and snowfall have not increased significantly during at least the past 50 years, and proxy data suggest that the atmospheric circulation over the interior has remained in a similar state for at least the past 200 years. Furthermore, the total sea ice cover around Antarctica has exhibited no significant overall change since reliable satellite monitoring began in the late 1970s, despite large but compensating regional changes. The inhomogeneity of Antarctic climate in space and time implies that recent Antarctic climate changes are due on the one hand to a combination of strong multi-decadal variability and anthropogenic effects and, as demonstrated by the paleoclimate record, on the other hand to multi-decadal to millennial scale and longer natural variability forced through changes in orbital insolation, greenhouse gases, solar variability, ice dynamics, and aerosols. Model projections suggest that over the 21st century the Antarctic interior will warm by 3.4° ± 1oC, and sea ice extent will decrease by ~30%. Ice sheet models are not yet adequate enough to answer pressing questions about the effect of projected warming on mass balance and sea level. Considering the potentially major impacts of a warming climate on Antarctica, vigorous efforts are needed to better understand all aspects of the highly coupled Antarctic climate system as well as its influence on the Earth's climate and oceans.