Investigating the characteristics and transformation of water-soluble carbonaceous matter in the cryosphere regions is important for understanding biogeochemical process in the earth system.Water-soluble carbonaceous ...Investigating the characteristics and transformation of water-soluble carbonaceous matter in the cryosphere regions is important for understanding biogeochemical process in the earth system.Water-soluble carbonaceous matter is a heterogeneous mixture of organic compounds that is soluble in aquatic environments.Despite its importance,we still lack systematic understanding for dissolved organic carbon(DOC)in several aspects including exact chemical composition and physical interactions with microorganisms,glacier meltwater.This review presents the chemical composition and physical properties of glacier DOC deposited through anthropogenic emission,terrestrial,and biogenic sources.We present the molecular composition of DOC and its effect over snow albedo and associated radiative forcings.Results indicate that DOC in snow/ice is made up of aromatic protein-like species,fulvic acid-like materials,and humic acid-like materials.Light-absorbing impurities in surface snow and glacier ice cause considerable albedo reduction and the associated radiative forcing is definitely positive.Water-soluble carbonaceous matter dominated the carbon transport in the high-altitude glacial area.Owing to prevailing global warming and projected increase in carbon emission,the glacial DOC is expected to release,which will have strong underlying impacts on cryosphere ecosystem.The results of this work have profound implications for better understanding the carbon cycle in high altitude cryosphere regions.A new compilation of globally distributed work is required,including large-scale measurements of glacial DOC over high-altitude cryosphere regions,to overcome and address the scientific challenges to constrain climate impacts of light-absorbing impurities related processes in Earth system and climate models.展开更多
Himalayan glaciers are shrinking rapidly,especially after 2000.Glacier shrinkage,however,shows a differential pattern in space and time,emphasizing the need to monitor and assess glacier changes at a larger scale.In t...Himalayan glaciers are shrinking rapidly,especially after 2000.Glacier shrinkage,however,shows a differential pattern in space and time,emphasizing the need to monitor and assess glacier changes at a larger scale.In this study,changes of 48 glaciers situated around the twin peaks of the Nun and Kun mountains in the northwestern Himalaya,hereafter referred to as Nun-Kun Group of Glaciers(NKGG),were investigated using Landsat satellite data during 2000-2020.Changes in glacier area,snout position,Equilibrium Line Altitude(ELA),surface thickness and glacier velocity were assessed using remote sensing data supplemented by field observations.The study revealed that the NKGG glaciers have experienced a recession of 4.5%±3.4%and their snouts have retreated at the rate of 6.4±1.6 m·a^(-1).Additionally,there was a 41%increase observed in the debris cover area during the observation period.Using the geodetic approach,an average glacier elevation change of-1.4±0.4 m·a^(-1)was observed between 2000 and 2012.The observed mass loss of the NKGG has resulted in the deceleration of glacier velocity from 27.0±3.7 m·a^(-1)in 2000 to 21.2±2.2 m·a^(-1)in 2020.The ELA has shifted upwards by 83.0±22 m during the period.Glacier morphological and topographic factors showed a strong influence on glacier recession.Furthermore,a higher recession of 12.9%±3.2%was observed in small glaciers,compared to 2.7%±3.1%in larger glaciers.The debris-covered glaciers showed lower shrinkage(2.8%±1.1%)compared to the clean glaciers(9.3%±5%).The glacier depletion recorded in the NKGG during the last two decades,if continued,would severely diminish glacial volume and capacity to store water,thus jeopardizing the sustainability of water resources in the basin.展开更多
The current article is an opinion on the sensitivity of high mountain regions which are the most fragile,sensitive and vulnerable to ongoing climate change.Its impacts are especially severe on the high mountain commun...The current article is an opinion on the sensitivity of high mountain regions which are the most fragile,sensitive and vulnerable to ongoing climate change.Its impacts are especially severe on the high mountain communities owing to their weak socio-economic profile,limited livelihood resources and agricultural land.The melting of glaciers and changes in the snow cover under the climate change scenario is leading to the scarcity of freshwater supplies,affecting both local and downstream communities.Changes in the precipitation patterns have been suggested to cause droughts,impact restricted agriculture,and limit the availability of water for domestic use.Additionally,the high mountain areas contain distinct flora and fauna,and climate change is not just altering them,but also has resulted in biodiversity loss as species are unable to adapt to the changing climate.Because of its higher altitudes and semi-arid to arid climate,the consequences of climate change are more evident in the higher Himalayas.Climate change is affecting the availability of key resources,such as freshwater and agriculture and pasture lands,resulting in food and water insecurity and their reliance on imports from other regions.As a result,high mountain communities in the Himalayas are progressively shifting to higher glacier valleys in search of suitable cultivable land with adequate irrigation.People are engaging in agro-pastoral activities around thermokarst lakes(Oasis)atop rock glaciers as part of this endeavour.Such actions underscore the crucial role of rock glaciers in dealing with and adjusting to the consequences of climate change.Despite its relevance,rock glacier research in the Himalayan region is still in its infancy.The purpose of this work is to emphasise the significance of these major climate-resilient water resources,as well as the methodology that must be adopted for their systematic and compressive investigations.展开更多
The paper discussed the influence of the forms of sediment accumulation on the surface of glaciers on their chemical and physicochemical properties.The materials sampled from the surface of five glaciers of the Svalba...The paper discussed the influence of the forms of sediment accumulation on the surface of glaciers on their chemical and physicochemical properties.The materials sampled from the surface of five glaciers of the Svalbard Archipelago was analyzed.We studied such forms of sediment accumulation as dirt cones-the ice core covered with sediments and cryoconite holes-hollows on the glacier surface containing cryoconite material.Parameters such as total organic carbon content,microbiological activity,pH,the content of mobile forms of potassium and phosphorus,and concentrations of heavy and trace metals were studied.Also,mesomorphological studies were carried out and the polydisperse composition of the sediments was determined.According to the results of this work,it was found that the content of organic carbon in the material selected from dirt cones and cryoconite holes can be up to 2.5%,but the content of clay particles in it is mainly at the 10–15%level.Potassium concentrations are up to 250 mg/kg,and phosphorus is up to 800 mg/kg.The content of metals is typical or lower than in the previously published data.The main influence on the chemical composition of materials has a geographical factor of the sampling site,rather than the form of material accumulation.展开更多
The evolution of mountainous topography is the result of the interactions of climate,topography,and erosion.Glaciers are one of the most active erosional forces sculpting mountainous regions.However,our ability to und...The evolution of mountainous topography is the result of the interactions of climate,topography,and erosion.Glaciers are one of the most active erosional forces sculpting mountainous regions.However,our ability to understand this erosional force is limited by the controversy regarding the major factors controlling glacial erosion.We selected the Nianbaoyeze Shan,which is occupied by subcontinental glaciers(likely cold-based or polythermal glaciers)in the northeastern Tibetan Plateau,to study how erosion by alpine glaciers sculpts the landscape.We first applied a power law model(y=axb)fit to the cross-profiles of glacial valleys and analyzed the controlling factor of glacial erosion;we then identified the morphometric characteristics of the cirques to analyze the influencing factors,and investigated the development patterns of glacial valleys and cirques.Finally,we used hypsometry and the slopealtitude curves and reconstructed the palaeo-glacier surfaces and palaeo-Equilibrium Line Altitudes(ELAs)to determine if the glacial buzzsaw effect had impacted this glaciated region with subcontinental glaciers.Our findings show that ice flux is the main factor controlling glacial erosion.In this region,decreasing temperatures promote an increase in glacier mean size(i.e.,ice flux),which enhances the rate of glacial erosion.Cirque morphology is mainly influenced by aspect and the ELA.The development patterns of glacial valleys and cirques were dominated by a widening process.The ELAs of Marine Isotope Stage(MIS)-3 derived from the cirque floor altitudes or the Accumulation Area Ratio(AAR)and Area-Altitude Balance Ratio(AABR)coincide with the hypsometric maximum and the reduction in slopealtitude curves,which indicates that glacial buzzsaw has impacted this region.Furthermore,the glacial buzzsaw effect has profoundly influenced the mountain heights and topographic evolution in this subcontinental glaciated region.展开更多
Around the Kunlun Peak there are many huge and broad mountains lifting above the Equilibrium Line altitade (ELA), forming the largest glacier distribution centre in China. Here the ELA is very high and the glacier exi...Around the Kunlun Peak there are many huge and broad mountains lifting above the Equilibrium Line altitade (ELA), forming the largest glacier distribution centre in China. Here the ELA is very high and the glacier existence is attributed to the unfavorableness of ablation, not the favorablenesses of accumulation. In the ablation period strong evaporation-sublimation and conduction expend a large amount of heat. restraining melting. In addition, meltwater is easy to refreeze. forming superimposed ice and then reducing mass loss. Low air temperature causes low ablation rate and short ablation period. Arid and cold climate is favorable to glacier development. comparable to the polar regions. Nonuniform precipitation decreases heat income during the ablation period and increases heat loss in winter. also resulting in restraining ablation.展开更多
Mountain glaciers in China are an important water source for both China and adjoining countries, and therefore their adaptation to glacier change is crucial in relation to maintaining populations. This study aims to i...Mountain glaciers in China are an important water source for both China and adjoining countries, and therefore their adaptation to glacier change is crucial in relation to maintaining populations. This study aims to improve our understanding of glacial vulnerability to climate change to establish adaptation strategies. A glacial numerical model is developed using spatial principle component analysis (SPCA) supported by remote sensing (RS) and geographical information system (GIS) technologies. The model contains nine factors--slope, aspect, hillshade, elevation a.s.l., air temperature, precipitation, glacial area change percentage, glacial type and glacial area, describing topography, climate, and glacier characteristics. The vulnerability of glaciers to climate change is evaluated during the period of 1961-2007 on a regional scale, and in the 2030s and 2050s based on projections of air temperature and precipitation changes under the IPCC RCP6.0 scenario and of glacier change in the 21st century. Glacial vulnerability is graded into five levels: potential, light, medial, heavy, and very heavy, using natural breaks classification (NBC). The spatial distribution of glacial vulnerability and its temporal changes in the 21st century for the RCP6.0 scenario are analyzed, and the factors influencing vulnerability are discussed. Results show that mountain glaciers in China are very vulnerable to climate change, and 41.2% of glacial areas fall into the levels of heavy and very heavy vulnerability in the period 1961-2007. This is mainly explained by topographical exposure and the high sensitivity of glaciers to climate change. Trends of glacial vulnerability are projected to decline in the 2030s and 2050s, but a declining trend is still high in some regions. In addition to topographical factors, variation in precipitation in the 2030s and 2050s is found to be crucial.展开更多
The article considers the variability of Nenskra and Nakra River basins glaciers’ parameters in the years of 1911-2014. Nenskra and Nakra River basins are located on the southern slope of the Great Caucasus, between ...The article considers the variability of Nenskra and Nakra River basins glaciers’ parameters in the years of 1911-2014. Nenskra and Nakra River basins are located on the southern slope of the Great Caucasus, between the Kharikhra, Shdavleri and Tsalgmili ranges, in Georgia, in particular in the Enguri River basin. In our research we used the catalogue of the glaciers of Georgia compiled by K. Podozerskiy in 1911. We also used the military topographic maps with the scale of 1:25,000 and 1:50,000 drawn up in 1960 (in former Soviet Union), where there are the glaciers mapped in detail and the ends of their ice tongues on the southern slope of Great Caucasus of those times. We also used the remote sensing method, which is the best modern way for the study of the dynamics of glaciers and this method is remarkable by a quick obtaining of results. The spectral images of the Landsat L8 OLI/TIRS (Operational Land Imager and Thermal Infrared Sensor) (USGS) received from the “Landsat” artificial satellite are the necessary materials for our study. We also used the field survey materials of 2014 (GPS data). The latest statistical information is also given about the glaciers located in the individual river basins;their morphological types, exposition and the dynamics are considered according to the individual years.展开更多
Weather and climate conditions drive the evolution of tropical glaciers which play an important role as water reservoirs for Peruvian inhabitants in the arid coast and semi-arid Andean region.The scarcity of long-term...Weather and climate conditions drive the evolution of tropical glaciers which play an important role as water reservoirs for Peruvian inhabitants in the arid coast and semi-arid Andean region.The scarcity of long-term high-quality observations over Peruvian glaciers has motivated the extensive use of reanalysis data to describe the climatic evolution of these glaciers.However,the representativeness and uncertainties of these reanalysis products over these glaciers are still poorly constrained.This study evaluates the ability of the ERA-Land reanalysis(ERAL)to reproduce hourly and monthly 2 m air temperature and relative humidity(T2m and Rh2m,respectively)over several Peruvian glaciers.We compared the ERAL with data from four on-glacier automatic weather stations(AWS),whose hourly time series were completed with nearby stations,for the period January 2017 to December 2019.Results indicates a better performance of the reanalysis for T2m(r>0.80)than for Rh2m(~0.4<r<~0.6)in all four glaciers.Concerning the observations,both parameters show a daily cycle influenced by the presence of the glacier.This influence is more prominent during the dry months when the so-called glacier damping and cooling effects are stronger.On a monthly time scale,the ERAL validation for both parameters are better in wet outer tropical sites(RMSE between±0.2℃ for T2m and between 3%-7% for Rh2m)rather than in dry outer tropical sites(RMSE between±0.2℃ for T2m and between 3%-7% for Rh2m).Among all sites considered in the study,the Rh2m bias is the highest in the Cavalca glacier(correlation of 0.81;RMSE 13%,MAE 11% and bias 8.3%)and the lowest in Artesonraju glacier(correlation of 0.96;RMSE 3%;MAE 2.3% and bias-0.8%).Based on certain considerations outlined in this paper,it is appropriate to use ERAL to characterize T2m and Rh2m conditions on Peruvian glaciers,particularly in the wet outer tropics.展开更多
We selected four typical glaciers in the Qilian Mountains and investigated their movements and variation using advanced technologies such as remote sensing, photographic measurements, and global positioning systems. T...We selected four typical glaciers in the Qilian Mountains and investigated their movements and variation using advanced technologies such as remote sensing, photographic measurements, and global positioning systems. The velocity of glacier movements in the Qilian Mountains is relatively low, and there has been no significant variation during the past 50 years. Glacier motion has maintained a normal style. The movement velocity of Laohugou Glacier No. 12 presented a decreasing trend (by 48%) from 1960 to 2012. The movement velocity of the Qiyi Glacier also presented a decreasing trend (by 48.1%) from 1958 to 2012; it decreased by 29.4% from 1958 to 1977 and by 26.5% from 1977 to 2012. Therefore, the Qiyi Glacier's movement velocity varied greatly over the earlier 20 years (1958 1977), but presented a small decreasing trend during the latter 30 years (1977-2012). By comparing the movement velocity variation of these typical glaciers, we determined that the extent of variation was consistent among large glaciers (such as Laohugou Glacier No. 12) and small glaciers (such as the Qiyi Glacier and Yanglonghe Glacier No. 5), despite their different sizes.展开更多
The article presents the changes in the number and area of the Dolra River basin glaciers during the last century in connection with the climate elements. Dolra River basin is located in the south-ern slope of the Cen...The article presents the changes in the number and area of the Dolra River basin glaciers during the last century in connection with the climate elements. Dolra River basin is located in the south-ern slope of the Central Caucasus, in the territory of Zemo Svaneti and joins the Enguri River basin, which in its turn is the main center of the contemporary glaciation in Georgia. During the study, we used the 1:42,000 scale topographic maps of the 19th century, which were drawn up during the first topographic survey by using the plane-table surveying method. Also, we used the catalog of the glaciers of the southern slope of the Caucasus compiled on the basis of the 19th century maps in 1911 by a well-known researcher of the Caucasus K. Podozerskiy. In order to identify the area and number of the glaciers of the 60s of the 20th century, we used the work of R. Gobejishvili—the Georgian glaciologist of the 20th-21st centuries, composed on the basis of 1:50,000 scale topo-graphic maps of 1960. The data of 2014 have been obtained by the Landsat aerial images of L8 OLI/TIRS (Operational Land Imager and Thermal Infrared Sensor) taken in August 2014. In the mentioned study, except of the old topographic maps and aerial images, we used the climate in-formation that we have collected from Mestia weather stations (Mestia is the regional center of Zemo Svaneti, where the only operating weather station is located at present). Along with the dy-namics of glaciers, the course of the air temperature and atmospheric precipitation has been iden-tified in the 20th century and in the beginning of the 21st century.展开更多
Based on various data,it can be concluded that eight monsoonal temperate glaciers in China were in stationary or ad-vancing between 1900s;930s and 1960s;980s,and were in retreating during 1930s;960s and 1980s;resent u...Based on various data,it can be concluded that eight monsoonal temperate glaciers in China were in stationary or ad-vancing between 1900s;930s and 1960s;980s,and were in retreating during 1930s;960s and 1980s;resent under the background of climate warming.The total glacier area has reduced by 3.11 km2 with a mean front altitude rise of 3.2 m/yr and 4 glaciers have disappeared in Mt.Yulong during 1957;999.Mass balance records indicated that glaciers had suf-fered a constant mass loss of snow and ice during the last several decades,and the accumulated mass balance in Hailuogou basin in Mt.Gongga was 10.83 m water equivalent in the past 45 years with a annual mean value of-0.24 m,and the value at Baishui glacier No.1 was-11.38 m water equivalent in the past 52 years with-0.22 m/yr.The inverse variation between mass balance and temperature in China and the Northern Hemisphere reflected that climate warming is mainly corresponding to constant ice and snow mass loss in the past 50 years.The change of the glaciers’ surface mor-phology has occurred since the 1980s,such as enlargement of glacier-lake and ice falls,resulted from the accelrative cli-mate warming.展开更多
The margin of the Greenland ice sheet has undergone rapid changes over the past decade as a result of the thinning, acceleration, and retreat of many fast-flowing tidewater outlet glaciers. Satellite observations show...The margin of the Greenland ice sheet has undergone rapid changes over the past decade as a result of the thinning, acceleration, and retreat of many fast-flowing tidewater outlet glaciers. Satellite observations show that three major tidewater outlet glaciers in Greenland retreated between 2000 and 2005, with synchronous increases in flow speed, causing a deficit in ice sheet mass budget and the potential for sea level rise. In this study, we investigated whether this acceleration was related to surface melt processes, and found that both flow speed and positive degree day (PDD) anomalies of the three glaciers varied together, indicating a causal relationship. Jakobshavn Isbr^e had lower flow speeds before 2000, during which PDD anomalies were negative, except for modest warming in 1993 and 1995. From 1999-2000, during which it is thought a threshold was passed, the flow speed of the glacier started to increase. However, the two glaciers in east Greenland showed a delayed response. Abrupt warming occurred in the vicinity of the two glaciers around 2001, but flow speed did not increase until 2003 for the Helheim Glacier, and until 2004 for the Kangerdlugssuaq Glacier. Furthermore, the two eastern glaciers switched to a deceleration mode more quickly than Jakobshavn lsbr^e. The observed differences in both acceleration and deceleration among the glaciers suggest that the relationship between surface melt and outlet glacier dynamics is not simple but complex.展开更多
This study makes an attempt to investigate through statistical analysis the correlation between changes in ice volume and area of glaciers. Using data from nine sample glaciers in the Tian Shan, the results show that ...This study makes an attempt to investigate through statistical analysis the correlation between changes in ice volume and area of glaciers. Using data from nine sample glaciers in the Tian Shan, the results show that a linear relation exists between changes in ice volume and area, with a correlation coefficient of 0.700. However, the accuracy estimation is difficult due to the limited number of samples. The correlation was not improved after adding eleven glacier samples in other mountains. Two reference glaciers are then analyzed in more detail. The linear correlation coefficient is higher than 0.800 when using the observed changes in ice volume and area during different periods on Urumqi Glacier No. 1, which suggests that the linear relation is valid for one glacier for different periods if its shape does not change noticeably and also for other glaciers of the same shape during the same period. The relation between changes in ice volume and area of Qingbingtan Glacier No. 72 is different during different periods due to change in the shape of the glacier tongue and the influence of the debris cover. Moreover, errors in glacier-change monitoring and-volume estimation have an important influence on the correlation results. Therefore, further study needs to focus not only on the distinction between glacier types and between different periods but also on the accuracy of volume estimation.展开更多
Tropical glaciers are extremely sensitive to a warming climate. In this paper, the evolution of the remaining tropical glaciers in Australasia(Irian Jaya, Indonesia) during the period 1988-2015 was quantified. Landsat...Tropical glaciers are extremely sensitive to a warming climate. In this paper, the evolution of the remaining tropical glaciers in Australasia(Irian Jaya, Indonesia) during the period 1988-2015 was quantified. Landsat series images, a digital elevation model from SRTM, and previously published data were used. Estimated total glacier area in 1988, 1993, 1997 and 2004 was 3.85 km2±0.13 km2, 3.01 km2±0.08 km2, 2.49 km2±0.07 km2 and 1.725 km2 ±0.042 km2, respectively. Only 0.58 km2±0.016 km2 glacierized area remained in 2015 in Puncak Jaya, which is about 84.9% loss in just 27 years. If this rate continued, the remaining tropical glaciers in Australasia would disappear in the 2020 s. Timeseries analysis of climate variables showed significant positive trends in air temperature(0.009°C per year) and relative humidity(0.43% per year) but no considerable tendency was observed for precipitation. Warming climate together with mining activities would accelerate loss of glacier coverage in this region.展开更多
-Rock glaciers are developed at permafrost areas of periglacial environment in Tianshan Mountains [7,17]. Based on field surveying andair-photo interprestation, the paper discusses the shape, characteristics of supply...-Rock glaciers are developed at permafrost areas of periglacial environment in Tianshan Mountains [7,17]. Based on field surveying andair-photo interprestation, the paper discusses the shape, characteristics of supply area, formation conditions and environmental differentiations of rockglaciers at head area of Urmqi River (43°05'-43°08' N, 86°48’-86°53E) inKalawuchen Range and the head areas of Toudao River and Danangou River (43°30’-43°50’N, 85°00-85°30’E) in Yilanhabierga Rangu at ShawanCounty. Formation conditions and morphological characteristics of rockglaciers are studies in terms of topographic conditions, climate, compositionand age.展开更多
China’s Northwest Arid Region(NAR),with dry and cold climate conditions and glaciers widely developed in the high mountains,provides vital water resources for Asia.The consecutive cold,warm,dry and wet days have much...China’s Northwest Arid Region(NAR),with dry and cold climate conditions and glaciers widely developed in the high mountains,provides vital water resources for Asia.The consecutive cold,warm,dry and wet days have much higher impacts on the water cycle process in this region than extreme temperature and precipitation events with short durations but high intensities.Parametric and nonparametric trend analysis methods widely used in climatology and hydrology are employed to identify the temporal and spatial features of the changes in the consecutive cold,warm,dry and wet days in the NAR based on China’s 0.5°×0.5°meteorological grid datasets of daily temperature and precipitation from 1961 to 2018.This study found that(1)the consecutive cold days(Cold Spell Duration Indicator,CSDI),and the consecutive dry days(CDD)decreased,while the consecutive warm days(Warm Spell Duration Indicator,WSDI),and the consecutive wet days(CWD)increased from 1961 to 2018,(2)and the eastern Kunlun Mountains were the hot spots where all of these consecutive climate indices changed significantly,(3)and the changes in these consecutive climate indices were highly correlated with the rise in the Global Mean Land/Ocean Temperature Index.The results indicated that winters tended to warmer and dryer and summer became hotter and wetter during 1961–2018 in the NAR under the global warming,which can lead to the sustained glacier retreat and the increase in summer runoff in this region,and the eastern Kunlun Mountains are the area where could face high risks of water scarcity and floods if the changes in these climate indices continue in the future.Given the vulnerability of the socio-economic systems in the NAR to a water shortage and floods,it is most crucial to improve the strategies of water resources management,disaster prevention and risk management for this region under climate change.展开更多
The article considers the variability glaciers parameters of Headwaters of the Enguri River in the years of 1960-1986-2014. The headwaters of The Enguri Riverare located on the southern slope of the Greater Caucasus, ...The article considers the variability glaciers parameters of Headwaters of the Enguri River in the years of 1960-1986-2014. The headwaters of The Enguri Riverare located on the southern slope of the Greater Caucasus, in Georgia. Detailed morphologic and morphometric description of glaciers is given. During our research, we used the topographic maps of 1960 and Landsat L5 TM (Thematic Mapper) aerial images, taken in August 1986 and 2014, and the GPS data of 2014. In the mentioned study, except for the old topographic maps and aerial images we used the climate information that we have collected from Mestia weather station (Mestia is the regional center of Zemo Svaneti), which is the only operating weather station in region. Along with the dynamics of glaciers the course of the air temperature has been identified, mainly trends of mean annual and monthly air temperatures for different periods 1961-2013, 1961-1986, 1987-2013 are made. According to them, main reasons for glacier retreat areanalyzed.展开更多
The reduction of glaciers of Mulkhura River basin over the last century is revised in the paper. Mulkhura River basin is located on the southern slope of the central Caucasus from the Mount Bashili (4148 m) to the Mou...The reduction of glaciers of Mulkhura River basin over the last century is revised in the paper. Mulkhura River basin is located on the southern slope of the central Caucasus from the Mount Bashili (4148 m) to the Mount Gistola (4860 m) and it is the main center of the contemporary glaciations in the Enguri River basin. The percentage reduction of areas of compound valley glaciers with the relation of air temperature and atmospheric precipitation is given in this paper. Also the paper considered the dynamics of the Tviberi and Tsaneriglaciers, which were the Georgia’s largest glaciers at the end of the 19th century. We used the catalog of the glaciers of the southern slope of the Caucasus compiled in 1911 by a well-known researcher of the Caucasus K. Podozerskiy, which was drawn up on the basis of the 19th century maps. In order to identify the area and number of the glaciers of the 60s of the 20th century, we used the work of R. Gobejishvili—the Georgian glaciologist of the 20th-21st centuries, composed on the basis of 1:50,000 scale topographic maps of 1960. The data of 2014 have been obtained by the Landsat aerial images of L8 OLI/TIRS (Operational Land Imager and Thermal Infrared Sensor) taken in August 2014. In the mentioned study, except of the old topographic maps and aerial images, we used the climate information especially air temperature and precipitation data of the Mestia weather station.展开更多
Glaciers one-time involves the citizenship in the development of a popular scientific project, which, among its objectives, aims to make the society conscious of the glacial retreat in action and to quantify the chang...Glaciers one-time involves the citizenship in the development of a popular scientific project, which, among its objectives, aims to make the society conscious of the glacial retreat in action and to quantify the changes in the mountain landscape. All are invited to take photographs of the modern Italian glaciers with the exact points of view of historical photographs, and to make photographic comparisons. Glaciers one-time is carried out in collaboration with institutions that carry out glaciological activities. The institutional network so has the goal to cooperate together for the promotion of research within the society and the understanding of the landscape changes due to retreat of the glaciers. With the active participation of citizenship, it was possible to do a picture of glaciation to publicize the awareness of the state of health of the glaciers and to disseminate the importance of the cryosphere.展开更多
基金supported by the second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0605)the National Natural Science Foundation of China(41971080)the support of Youth Innovation Promotion Association CAS(2021429)。
文摘Investigating the characteristics and transformation of water-soluble carbonaceous matter in the cryosphere regions is important for understanding biogeochemical process in the earth system.Water-soluble carbonaceous matter is a heterogeneous mixture of organic compounds that is soluble in aquatic environments.Despite its importance,we still lack systematic understanding for dissolved organic carbon(DOC)in several aspects including exact chemical composition and physical interactions with microorganisms,glacier meltwater.This review presents the chemical composition and physical properties of glacier DOC deposited through anthropogenic emission,terrestrial,and biogenic sources.We present the molecular composition of DOC and its effect over snow albedo and associated radiative forcings.Results indicate that DOC in snow/ice is made up of aromatic protein-like species,fulvic acid-like materials,and humic acid-like materials.Light-absorbing impurities in surface snow and glacier ice cause considerable albedo reduction and the associated radiative forcing is definitely positive.Water-soluble carbonaceous matter dominated the carbon transport in the high-altitude glacial area.Owing to prevailing global warming and projected increase in carbon emission,the glacial DOC is expected to release,which will have strong underlying impacts on cryosphere ecosystem.The results of this work have profound implications for better understanding the carbon cycle in high altitude cryosphere regions.A new compilation of globally distributed work is required,including large-scale measurements of glacial DOC over high-altitude cryosphere regions,to overcome and address the scientific challenges to constrain climate impacts of light-absorbing impurities related processes in Earth system and climate models.
基金as part of the Department of Science and Technology (DST), Government of India sponsored research projects titled “Centre of Excellence for Glaciological Research in Western Himalaya”the financial assistance received from the Department under the projects to conduct the research。
文摘Himalayan glaciers are shrinking rapidly,especially after 2000.Glacier shrinkage,however,shows a differential pattern in space and time,emphasizing the need to monitor and assess glacier changes at a larger scale.In this study,changes of 48 glaciers situated around the twin peaks of the Nun and Kun mountains in the northwestern Himalaya,hereafter referred to as Nun-Kun Group of Glaciers(NKGG),were investigated using Landsat satellite data during 2000-2020.Changes in glacier area,snout position,Equilibrium Line Altitude(ELA),surface thickness and glacier velocity were assessed using remote sensing data supplemented by field observations.The study revealed that the NKGG glaciers have experienced a recession of 4.5%±3.4%and their snouts have retreated at the rate of 6.4±1.6 m·a^(-1).Additionally,there was a 41%increase observed in the debris cover area during the observation period.Using the geodetic approach,an average glacier elevation change of-1.4±0.4 m·a^(-1)was observed between 2000 and 2012.The observed mass loss of the NKGG has resulted in the deceleration of glacier velocity from 27.0±3.7 m·a^(-1)in 2000 to 21.2±2.2 m·a^(-1)in 2020.The ELA has shifted upwards by 83.0±22 m during the period.Glacier morphological and topographic factors showed a strong influence on glacier recession.Furthermore,a higher recession of 12.9%±3.2%was observed in small glaciers,compared to 2.7%±3.1%in larger glaciers.The debris-covered glaciers showed lower shrinkage(2.8%±1.1%)compared to the clean glaciers(9.3%±5%).The glacier depletion recorded in the NKGG during the last two decades,if continued,would severely diminish glacial volume and capacity to store water,thus jeopardizing the sustainability of water resources in the basin.
文摘The current article is an opinion on the sensitivity of high mountain regions which are the most fragile,sensitive and vulnerable to ongoing climate change.Its impacts are especially severe on the high mountain communities owing to their weak socio-economic profile,limited livelihood resources and agricultural land.The melting of glaciers and changes in the snow cover under the climate change scenario is leading to the scarcity of freshwater supplies,affecting both local and downstream communities.Changes in the precipitation patterns have been suggested to cause droughts,impact restricted agriculture,and limit the availability of water for domestic use.Additionally,the high mountain areas contain distinct flora and fauna,and climate change is not just altering them,but also has resulted in biodiversity loss as species are unable to adapt to the changing climate.Because of its higher altitudes and semi-arid to arid climate,the consequences of climate change are more evident in the higher Himalayas.Climate change is affecting the availability of key resources,such as freshwater and agriculture and pasture lands,resulting in food and water insecurity and their reliance on imports from other regions.As a result,high mountain communities in the Himalayas are progressively shifting to higher glacier valleys in search of suitable cultivable land with adequate irrigation.People are engaging in agro-pastoral activities around thermokarst lakes(Oasis)atop rock glaciers as part of this endeavour.Such actions underscore the crucial role of rock glaciers in dealing with and adjusting to the consequences of climate change.Despite its relevance,rock glacier research in the Himalayan region is still in its infancy.The purpose of this work is to emphasise the significance of these major climate-resilient water resources,as well as the methodology that must be adopted for their systematic and compressive investigations.
基金supported by Russian Foundation for Basic Research(project No 19-05-50107)"The role of microparticles of organic carbon in degradation of ice cover of polar regions of the Earth and in the process of soil-like bodies formation".
文摘The paper discussed the influence of the forms of sediment accumulation on the surface of glaciers on their chemical and physicochemical properties.The materials sampled from the surface of five glaciers of the Svalbard Archipelago was analyzed.We studied such forms of sediment accumulation as dirt cones-the ice core covered with sediments and cryoconite holes-hollows on the glacier surface containing cryoconite material.Parameters such as total organic carbon content,microbiological activity,pH,the content of mobile forms of potassium and phosphorus,and concentrations of heavy and trace metals were studied.Also,mesomorphological studies were carried out and the polydisperse composition of the sediments was determined.According to the results of this work,it was found that the content of organic carbon in the material selected from dirt cones and cryoconite holes can be up to 2.5%,but the content of clay particles in it is mainly at the 10–15%level.Potassium concentrations are up to 250 mg/kg,and phosphorus is up to 800 mg/kg.The content of metals is typical or lower than in the previously published data.The main influence on the chemical composition of materials has a geographical factor of the sampling site,rather than the form of material accumulation.
基金funded by the National Natural Science Foundation of China(Grant Nos.41971003)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant Nos.2019QZKK0205)the Science and technology Project of Tibet Autonomous Region(Grant Nos.XZ202101ZY0001G)。
文摘The evolution of mountainous topography is the result of the interactions of climate,topography,and erosion.Glaciers are one of the most active erosional forces sculpting mountainous regions.However,our ability to understand this erosional force is limited by the controversy regarding the major factors controlling glacial erosion.We selected the Nianbaoyeze Shan,which is occupied by subcontinental glaciers(likely cold-based or polythermal glaciers)in the northeastern Tibetan Plateau,to study how erosion by alpine glaciers sculpts the landscape.We first applied a power law model(y=axb)fit to the cross-profiles of glacial valleys and analyzed the controlling factor of glacial erosion;we then identified the morphometric characteristics of the cirques to analyze the influencing factors,and investigated the development patterns of glacial valleys and cirques.Finally,we used hypsometry and the slopealtitude curves and reconstructed the palaeo-glacier surfaces and palaeo-Equilibrium Line Altitudes(ELAs)to determine if the glacial buzzsaw effect had impacted this glaciated region with subcontinental glaciers.Our findings show that ice flux is the main factor controlling glacial erosion.In this region,decreasing temperatures promote an increase in glacier mean size(i.e.,ice flux),which enhances the rate of glacial erosion.Cirque morphology is mainly influenced by aspect and the ELA.The development patterns of glacial valleys and cirques were dominated by a widening process.The ELAs of Marine Isotope Stage(MIS)-3 derived from the cirque floor altitudes or the Accumulation Area Ratio(AAR)and Area-Altitude Balance Ratio(AABR)coincide with the hypsometric maximum and the reduction in slopealtitude curves,which indicates that glacial buzzsaw has impacted this region.Furthermore,the glacial buzzsaw effect has profoundly influenced the mountain heights and topographic evolution in this subcontinental glaciated region.
文摘Around the Kunlun Peak there are many huge and broad mountains lifting above the Equilibrium Line altitade (ELA), forming the largest glacier distribution centre in China. Here the ELA is very high and the glacier existence is attributed to the unfavorableness of ablation, not the favorablenesses of accumulation. In the ablation period strong evaporation-sublimation and conduction expend a large amount of heat. restraining melting. In addition, meltwater is easy to refreeze. forming superimposed ice and then reducing mass loss. Low air temperature causes low ablation rate and short ablation period. Arid and cold climate is favorable to glacier development. comparable to the polar regions. Nonuniform precipitation decreases heat income during the ablation period and increases heat loss in winter. also resulting in restraining ablation.
基金supported by grants from the National Basic Research Program of China (2013CBA01808)the National Natural Science Foundation of China (41271088)
文摘Mountain glaciers in China are an important water source for both China and adjoining countries, and therefore their adaptation to glacier change is crucial in relation to maintaining populations. This study aims to improve our understanding of glacial vulnerability to climate change to establish adaptation strategies. A glacial numerical model is developed using spatial principle component analysis (SPCA) supported by remote sensing (RS) and geographical information system (GIS) technologies. The model contains nine factors--slope, aspect, hillshade, elevation a.s.l., air temperature, precipitation, glacial area change percentage, glacial type and glacial area, describing topography, climate, and glacier characteristics. The vulnerability of glaciers to climate change is evaluated during the period of 1961-2007 on a regional scale, and in the 2030s and 2050s based on projections of air temperature and precipitation changes under the IPCC RCP6.0 scenario and of glacier change in the 21st century. Glacial vulnerability is graded into five levels: potential, light, medial, heavy, and very heavy, using natural breaks classification (NBC). The spatial distribution of glacial vulnerability and its temporal changes in the 21st century for the RCP6.0 scenario are analyzed, and the factors influencing vulnerability are discussed. Results show that mountain glaciers in China are very vulnerable to climate change, and 41.2% of glacial areas fall into the levels of heavy and very heavy vulnerability in the period 1961-2007. This is mainly explained by topographical exposure and the high sensitivity of glaciers to climate change. Trends of glacial vulnerability are projected to decline in the 2030s and 2050s, but a declining trend is still high in some regions. In addition to topographical factors, variation in precipitation in the 2030s and 2050s is found to be crucial.
文摘The article considers the variability of Nenskra and Nakra River basins glaciers’ parameters in the years of 1911-2014. Nenskra and Nakra River basins are located on the southern slope of the Great Caucasus, between the Kharikhra, Shdavleri and Tsalgmili ranges, in Georgia, in particular in the Enguri River basin. In our research we used the catalogue of the glaciers of Georgia compiled by K. Podozerskiy in 1911. We also used the military topographic maps with the scale of 1:25,000 and 1:50,000 drawn up in 1960 (in former Soviet Union), where there are the glaciers mapped in detail and the ends of their ice tongues on the southern slope of Great Caucasus of those times. We also used the remote sensing method, which is the best modern way for the study of the dynamics of glaciers and this method is remarkable by a quick obtaining of results. The spectral images of the Landsat L8 OLI/TIRS (Operational Land Imager and Thermal Infrared Sensor) (USGS) received from the “Landsat” artificial satellite are the necessary materials for our study. We also used the field survey materials of 2014 (GPS data). The latest statistical information is also given about the glaciers located in the individual river basins;their morphological types, exposition and the dynamics are considered according to the individual years.
基金funded by the Ministry of Science and Innovation of Spain through the research project(PID2020-113247RA-C22)by the National Fund for Scientific and Technological Development of Peru trough the PERMAFROST ENSO research project(081-2021)。
文摘Weather and climate conditions drive the evolution of tropical glaciers which play an important role as water reservoirs for Peruvian inhabitants in the arid coast and semi-arid Andean region.The scarcity of long-term high-quality observations over Peruvian glaciers has motivated the extensive use of reanalysis data to describe the climatic evolution of these glaciers.However,the representativeness and uncertainties of these reanalysis products over these glaciers are still poorly constrained.This study evaluates the ability of the ERA-Land reanalysis(ERAL)to reproduce hourly and monthly 2 m air temperature and relative humidity(T2m and Rh2m,respectively)over several Peruvian glaciers.We compared the ERAL with data from four on-glacier automatic weather stations(AWS),whose hourly time series were completed with nearby stations,for the period January 2017 to December 2019.Results indicates a better performance of the reanalysis for T2m(r>0.80)than for Rh2m(~0.4<r<~0.6)in all four glaciers.Concerning the observations,both parameters show a daily cycle influenced by the presence of the glacier.This influence is more prominent during the dry months when the so-called glacier damping and cooling effects are stronger.On a monthly time scale,the ERAL validation for both parameters are better in wet outer tropical sites(RMSE between±0.2℃ for T2m and between 3%-7% for Rh2m)rather than in dry outer tropical sites(RMSE between±0.2℃ for T2m and between 3%-7% for Rh2m).Among all sites considered in the study,the Rh2m bias is the highest in the Cavalca glacier(correlation of 0.81;RMSE 13%,MAE 11% and bias 8.3%)and the lowest in Artesonraju glacier(correlation of 0.96;RMSE 3%;MAE 2.3% and bias-0.8%).Based on certain considerations outlined in this paper,it is appropriate to use ERAL to characterize T2m and Rh2m conditions on Peruvian glaciers,particularly in the wet outer tropics.
基金supported by CAS(KJZD-EW-G03-04)the Global Change Research Program of China(No.2010CB951404)the National Natural Science Foundation of China(No.41071043)
文摘We selected four typical glaciers in the Qilian Mountains and investigated their movements and variation using advanced technologies such as remote sensing, photographic measurements, and global positioning systems. The velocity of glacier movements in the Qilian Mountains is relatively low, and there has been no significant variation during the past 50 years. Glacier motion has maintained a normal style. The movement velocity of Laohugou Glacier No. 12 presented a decreasing trend (by 48%) from 1960 to 2012. The movement velocity of the Qiyi Glacier also presented a decreasing trend (by 48.1%) from 1958 to 2012; it decreased by 29.4% from 1958 to 1977 and by 26.5% from 1977 to 2012. Therefore, the Qiyi Glacier's movement velocity varied greatly over the earlier 20 years (1958 1977), but presented a small decreasing trend during the latter 30 years (1977-2012). By comparing the movement velocity variation of these typical glaciers, we determined that the extent of variation was consistent among large glaciers (such as Laohugou Glacier No. 12) and small glaciers (such as the Qiyi Glacier and Yanglonghe Glacier No. 5), despite their different sizes.
文摘The article presents the changes in the number and area of the Dolra River basin glaciers during the last century in connection with the climate elements. Dolra River basin is located in the south-ern slope of the Central Caucasus, in the territory of Zemo Svaneti and joins the Enguri River basin, which in its turn is the main center of the contemporary glaciation in Georgia. During the study, we used the 1:42,000 scale topographic maps of the 19th century, which were drawn up during the first topographic survey by using the plane-table surveying method. Also, we used the catalog of the glaciers of the southern slope of the Caucasus compiled on the basis of the 19th century maps in 1911 by a well-known researcher of the Caucasus K. Podozerskiy. In order to identify the area and number of the glaciers of the 60s of the 20th century, we used the work of R. Gobejishvili—the Georgian glaciologist of the 20th-21st centuries, composed on the basis of 1:50,000 scale topo-graphic maps of 1960. The data of 2014 have been obtained by the Landsat aerial images of L8 OLI/TIRS (Operational Land Imager and Thermal Infrared Sensor) taken in August 2014. In the mentioned study, except of the old topographic maps and aerial images, we used the climate in-formation that we have collected from Mestia weather stations (Mestia is the regional center of Zemo Svaneti, where the only operating weather station is located at present). Along with the dy-namics of glaciers, the course of the air temperature and atmospheric precipitation has been iden-tified in the 20th century and in the beginning of the 21st century.
基金supported by a Major Directionality Program of Chinese Academy of Sciences (KZCXZ-YW-317)a National Basic Re-search Program of China (2007CB411201)+4 种基金a Key Project of the National Natural Science Foundation of China (90511007)an Innovative Research Interna-tional Partnership Project of Chinese Academy of Sciences (CXTD-Z2005-2)a Project for Outstanding Young Scientists of Chinese Natural Science Founda-tion (40121101)a West Light Foundation of Chinese Academy of Sciences (O828A11001)the Foun-dation from The State Key Laboratory of Cryosphere Science and Lijiang City Government
文摘Based on various data,it can be concluded that eight monsoonal temperate glaciers in China were in stationary or ad-vancing between 1900s;930s and 1960s;980s,and were in retreating during 1930s;960s and 1980s;resent under the background of climate warming.The total glacier area has reduced by 3.11 km2 with a mean front altitude rise of 3.2 m/yr and 4 glaciers have disappeared in Mt.Yulong during 1957;999.Mass balance records indicated that glaciers had suf-fered a constant mass loss of snow and ice during the last several decades,and the accumulated mass balance in Hailuogou basin in Mt.Gongga was 10.83 m water equivalent in the past 45 years with a annual mean value of-0.24 m,and the value at Baishui glacier No.1 was-11.38 m water equivalent in the past 52 years with-0.22 m/yr.The inverse variation between mass balance and temperature in China and the Northern Hemisphere reflected that climate warming is mainly corresponding to constant ice and snow mass loss in the past 50 years.The change of the glaciers’ surface mor-phology has occurred since the 1980s,such as enlargement of glacier-lake and ice falls,resulted from the accelrative cli-mate warming.
基金Supported by the National Natural Science Foundation of China (No.40906096)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (No. Y0GQ031001)
文摘The margin of the Greenland ice sheet has undergone rapid changes over the past decade as a result of the thinning, acceleration, and retreat of many fast-flowing tidewater outlet glaciers. Satellite observations show that three major tidewater outlet glaciers in Greenland retreated between 2000 and 2005, with synchronous increases in flow speed, causing a deficit in ice sheet mass budget and the potential for sea level rise. In this study, we investigated whether this acceleration was related to surface melt processes, and found that both flow speed and positive degree day (PDD) anomalies of the three glaciers varied together, indicating a causal relationship. Jakobshavn Isbr^e had lower flow speeds before 2000, during which PDD anomalies were negative, except for modest warming in 1993 and 1995. From 1999-2000, during which it is thought a threshold was passed, the flow speed of the glacier started to increase. However, the two glaciers in east Greenland showed a delayed response. Abrupt warming occurred in the vicinity of the two glaciers around 2001, but flow speed did not increase until 2003 for the Helheim Glacier, and until 2004 for the Kangerdlugssuaq Glacier. Furthermore, the two eastern glaciers switched to a deceleration mode more quickly than Jakobshavn lsbr^e. The observed differences in both acceleration and deceleration among the glaciers suggest that the relationship between surface melt and outlet glacier dynamics is not simple but complex.
基金funded by the National Natural Science Foundation of China (41771077)the Funds for Creative Research Groups of China (41421061)+1 种基金the Strategic Priority Research Program of Chinese Acad emy of Sciences (XDA20020102)the Youth Innovation Promotion Association of CAS
文摘This study makes an attempt to investigate through statistical analysis the correlation between changes in ice volume and area of glaciers. Using data from nine sample glaciers in the Tian Shan, the results show that a linear relation exists between changes in ice volume and area, with a correlation coefficient of 0.700. However, the accuracy estimation is difficult due to the limited number of samples. The correlation was not improved after adding eleven glacier samples in other mountains. Two reference glaciers are then analyzed in more detail. The linear correlation coefficient is higher than 0.800 when using the observed changes in ice volume and area during different periods on Urumqi Glacier No. 1, which suggests that the linear relation is valid for one glacier for different periods if its shape does not change noticeably and also for other glaciers of the same shape during the same period. The relation between changes in ice volume and area of Qingbingtan Glacier No. 72 is different during different periods due to change in the shape of the glacier tongue and the influence of the debris cover. Moreover, errors in glacier-change monitoring and-volume estimation have an important influence on the correlation results. Therefore, further study needs to focus not only on the distinction between glacier types and between different periods but also on the accuracy of volume estimation.
基金Ton Duc Thang University, Ho Chi Minh City, Vietnam, for research support
文摘Tropical glaciers are extremely sensitive to a warming climate. In this paper, the evolution of the remaining tropical glaciers in Australasia(Irian Jaya, Indonesia) during the period 1988-2015 was quantified. Landsat series images, a digital elevation model from SRTM, and previously published data were used. Estimated total glacier area in 1988, 1993, 1997 and 2004 was 3.85 km2±0.13 km2, 3.01 km2±0.08 km2, 2.49 km2±0.07 km2 and 1.725 km2 ±0.042 km2, respectively. Only 0.58 km2±0.016 km2 glacierized area remained in 2015 in Puncak Jaya, which is about 84.9% loss in just 27 years. If this rate continued, the remaining tropical glaciers in Australasia would disappear in the 2020 s. Timeseries analysis of climate variables showed significant positive trends in air temperature(0.009°C per year) and relative humidity(0.43% per year) but no considerable tendency was observed for precipitation. Warming climate together with mining activities would accelerate loss of glacier coverage in this region.
文摘-Rock glaciers are developed at permafrost areas of periglacial environment in Tianshan Mountains [7,17]. Based on field surveying andair-photo interprestation, the paper discusses the shape, characteristics of supply area, formation conditions and environmental differentiations of rockglaciers at head area of Urmqi River (43°05'-43°08' N, 86°48’-86°53E) inKalawuchen Range and the head areas of Toudao River and Danangou River (43°30’-43°50’N, 85°00-85°30’E) in Yilanhabierga Rangu at ShawanCounty. Formation conditions and morphological characteristics of rockglaciers are studies in terms of topographic conditions, climate, compositionand age.
基金the Ministry of Science and Technology(Grant No.2018FY100502)the Young Talent Growth Fund Project of Northwest Institute of Ecological Environment and Resources,Chinese Academy of Sciences(Grant No.FEYS2019016)+2 种基金the National Natural Science Foundation of China(Grant No.41171378)the“Western Light”program of the Chinese Academy of Science(Grant No.2017-XBQNXZ-B-016)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2019430)。
文摘China’s Northwest Arid Region(NAR),with dry and cold climate conditions and glaciers widely developed in the high mountains,provides vital water resources for Asia.The consecutive cold,warm,dry and wet days have much higher impacts on the water cycle process in this region than extreme temperature and precipitation events with short durations but high intensities.Parametric and nonparametric trend analysis methods widely used in climatology and hydrology are employed to identify the temporal and spatial features of the changes in the consecutive cold,warm,dry and wet days in the NAR based on China’s 0.5°×0.5°meteorological grid datasets of daily temperature and precipitation from 1961 to 2018.This study found that(1)the consecutive cold days(Cold Spell Duration Indicator,CSDI),and the consecutive dry days(CDD)decreased,while the consecutive warm days(Warm Spell Duration Indicator,WSDI),and the consecutive wet days(CWD)increased from 1961 to 2018,(2)and the eastern Kunlun Mountains were the hot spots where all of these consecutive climate indices changed significantly,(3)and the changes in these consecutive climate indices were highly correlated with the rise in the Global Mean Land/Ocean Temperature Index.The results indicated that winters tended to warmer and dryer and summer became hotter and wetter during 1961–2018 in the NAR under the global warming,which can lead to the sustained glacier retreat and the increase in summer runoff in this region,and the eastern Kunlun Mountains are the area where could face high risks of water scarcity and floods if the changes in these climate indices continue in the future.Given the vulnerability of the socio-economic systems in the NAR to a water shortage and floods,it is most crucial to improve the strategies of water resources management,disaster prevention and risk management for this region under climate change.
文摘The article considers the variability glaciers parameters of Headwaters of the Enguri River in the years of 1960-1986-2014. The headwaters of The Enguri Riverare located on the southern slope of the Greater Caucasus, in Georgia. Detailed morphologic and morphometric description of glaciers is given. During our research, we used the topographic maps of 1960 and Landsat L5 TM (Thematic Mapper) aerial images, taken in August 1986 and 2014, and the GPS data of 2014. In the mentioned study, except for the old topographic maps and aerial images we used the climate information that we have collected from Mestia weather station (Mestia is the regional center of Zemo Svaneti), which is the only operating weather station in region. Along with the dynamics of glaciers the course of the air temperature has been identified, mainly trends of mean annual and monthly air temperatures for different periods 1961-2013, 1961-1986, 1987-2013 are made. According to them, main reasons for glacier retreat areanalyzed.
文摘The reduction of glaciers of Mulkhura River basin over the last century is revised in the paper. Mulkhura River basin is located on the southern slope of the central Caucasus from the Mount Bashili (4148 m) to the Mount Gistola (4860 m) and it is the main center of the contemporary glaciations in the Enguri River basin. The percentage reduction of areas of compound valley glaciers with the relation of air temperature and atmospheric precipitation is given in this paper. Also the paper considered the dynamics of the Tviberi and Tsaneriglaciers, which were the Georgia’s largest glaciers at the end of the 19th century. We used the catalog of the glaciers of the southern slope of the Caucasus compiled in 1911 by a well-known researcher of the Caucasus K. Podozerskiy, which was drawn up on the basis of the 19th century maps. In order to identify the area and number of the glaciers of the 60s of the 20th century, we used the work of R. Gobejishvili—the Georgian glaciologist of the 20th-21st centuries, composed on the basis of 1:50,000 scale topographic maps of 1960. The data of 2014 have been obtained by the Landsat aerial images of L8 OLI/TIRS (Operational Land Imager and Thermal Infrared Sensor) taken in August 2014. In the mentioned study, except of the old topographic maps and aerial images, we used the climate information especially air temperature and precipitation data of the Mestia weather station.
文摘Glaciers one-time involves the citizenship in the development of a popular scientific project, which, among its objectives, aims to make the society conscious of the glacial retreat in action and to quantify the changes in the mountain landscape. All are invited to take photographs of the modern Italian glaciers with the exact points of view of historical photographs, and to make photographic comparisons. Glaciers one-time is carried out in collaboration with institutions that carry out glaciological activities. The institutional network so has the goal to cooperate together for the promotion of research within the society and the understanding of the landscape changes due to retreat of the glaciers. With the active participation of citizenship, it was possible to do a picture of glaciation to publicize the awareness of the state of health of the glaciers and to disseminate the importance of the cryosphere.