Performance validation of High Mountain Asia 8-meter Digital Elevation Model using ICESat-2 geolocated photons

High Mountain Asia(HMA),recognized as a third pole,needs regular and intense studies as it is susceptible to climate change.An accurate and high-resolution Digital Elevation Model(DEM)for this region enables us to analyze it in a 3D environment and understand its intricate role as the Water Tower of Asia.The science teams of NASA realized an 8-m DEM using satellite stereo imagery for HMA,termed HMA 8-m DEM.In this research,we assessed the vertical accuracy of HMA 8-m DEM using reference elevations from ICESat-2 geolocated photons at three test sites of varied topography and land covers.Inferences were made from statistical quantifiers and elevation profiles.For the world’s highest mountain,Mount Everest,and its surroundings,Root Mean Squared Error(RMSE)and Mean Absolute Error(MAE)resulted in 1.94 m and 1.66 m,respectively;however,a uniform positive bias observed in the elevation profiles indicates the seasonal snow cover change will dent the accurate estimation of the elevation in this sort of test sites.The second test site containing gentle slopes with forest patches has exhibited the Digital Surface Model(DSM)features with RMSE and MAE of 0.58 m and 0.52 m,respectively.The third test site,situated in the Zanda County of the Qinghai-Tibet,is a relatively flat terrain bed,mostly bare earth with sudden river cuts,and has minimal errors with RMSE and MAE of 0.32 m and 0.29 m,respectively,and with a negligible bias.Additionally,in one more test site,the feasibility of detecting the glacial lakes was tested,which resulted in exhibiting a flat surface over the surface of the lakes,indicating the potential of HMA 8-m DEM for deriving the hydrological parameters.The results accrued in this investigation confirm that the HMA 8-m DEM has the best vertical accuracy and should be of high use for analyzing natural hazards and monitoring glacier surfaces.

Performance evaluation of CLM5.0 in simulating liquid soil water in high mountainous area,Northwest China

The model performance in simulating soil water content(SWC) is crucial for successfully modeling earth’s system,especially in high mountainous areas.In this study,the performance of Community Land Model 5.0(CLM5.0) in simulating liquid SWC was evaluated against observations from nine in-situ sites in the upper reach of the Heihe River Watershed(HRW),Northwest China.The CLM5.0 shows reliable performance in the study area with correlation coefficients(R) ranging between 0.79–0.93,root mean standard errors(RMSE)ranging between 0.044–0.097 m^(3)/m^(3),and the mean bias(BIAS) ranging between-0.084–0.061 m^(3)/m^(3).The slightly worse performance of CLM5.0 than CLM4.5 on alpine meadow and grassland is mainly caused by the revised canopy interception parameterization.The CLM5.0 overestimates interception and underestimates evapotranspiration(ET) on both alpine meadow and grassland during the growth period.The systematical overestimations at all the grassland sites indicate that the underestimation of ET is much larger than the overestimation of interception on grassland during growth period,while the errors of simulated interception and ET are partially canceled out on alpine meadow.Moreover,the underestimation of ET is more responsible for the overestimation of SWC than the overestimation of interception in the high mountainous area.It is necessary to estimate reasonable empirical parameter α(proportion of leaf water collection area) in interception parameterization scheme and further improve the dry surface layerbased soil evaporation resistance parameterization introduced in CLM5.0 in future researches.The performance of CLM5.0 is better under completely frozen stage than thawing stage and freezing stage,because of low variations of liquid SWC caused by extremely low hydraulic conductivity of soils.The underestimation of liquid SWC under frozen state is caused by underestimation of soil temperature,which leads to more ice mass and less liquid water in total water content.

Seasonal variations in glacier velocity in the High Mountain Asia region during 2015–2020

Velocity is an important component of glacier dynamics and directly reflects the response of glaciers to climate change.As a result,an accurate determination of seasonal variation in glacier velocity is very important in understanding the annual variation in glacier dynamics.However,few studies of glacier velocity in the High Mountain Asia(HMA)region were done.Along these lines,in this work,based on Sentinel-1 glacier velocity data,the distribution of glacier velocity in the HMA region was plotted and their seasonal variations during 2015-2020 were systematically analysed.The average glacier velocity in the HMA region was 0.053 m/d,and was positively correlated with the glacier area and slope.Glaciers in the Karakoram Mountains had the fastest average flow velocity(0.060 m/d),where the glaciers exhibited the largest average area and average slope.Moreover,glaciers in the GangdisêMountains had the slowest velocity(0.022 m/d)and the smallest average glacier area.The glacier flows were the fastest in spring(0.058 m/d),followed by summer(0.050 m/d),autumn(0.041 m/d),and winter(0.040 m/d).In addition,the glacier flows were the maximum in May,being 1.4 times of the annual average velocity.In some areas,such as the Qilian,Altun,Tibetan Interior,Eastern Kunlun,and Western Kunlun mountains,the peak glacier velocities appeared in June and July.The glacier velocity in the HMA region decreased in midsummer and reached the minimum in December when it was 75%of the annual average.These results highlight the role of meltwater in the seasonal variation in glacier flows in late spring and early summer.The seasonal velocity variation of lake-terminating glaciers was similar to that of land-terminating ones,but the former flowed faster.The velocity difference close to the mass balance line between the lake-and land-terminating glaciers was obviously greater in spring than in other seasons.In summer,the difference between the lake-and land-terminating glaciers at a normalized distance of 0.05-0.40 from the terminus was significantly greater than those of other seasons.The velocity difference between the lake-and land-terminating glaciers is closely related to the variable of ice thickness,and also to the frictional force of the terminal base reduced by proglacial lakes.Thus,it can be concluded that in addition to the variation of the glacier thickness and viscosity,the variation of glacier water input also plays a key role in the seasonal variation of glacier velocity.

Glacier mass balance in High Mountain Asia inferred from a GRACE release-6 gravity solution for the period 2002–2016

We provide estimates of glacier mass changes in the High Mountain Asia (HMA) area from April2002 to August 2016 by employing a new version of gravity solutions of the Gravity Recovery and ClimateExperiment (GRACE) twin-satellite mission. We find a total mass loss trend of the HMA glaciers at a rateof –22.17 (±1.96) Gt/a. The largest mass loss rates of –7.02 (±0.94) and –6.73 (±0.78) Gt/a are found forthe glaciers in Nyainqentanglha Mountains and Eastern Himalayas, respectively. Although most glaciers inthe HMA area show a mass loss, we find a small glacier mass gain of 1.19 (±0.55) and 0.77 (±0.37) Gt/a inKarakoram Mountains and Western Kunlun Mountains, respectively. There is also a nearly zero massbalance in Pamirs. Our estimates of glacier mass change trends confirm previous results from the analysisof altimetry data of the ICESat (ICE, Cloud and Land Elevation Satellite) and ASTER (AdvancedSpaceborne Thermal Emission and Reflection Radiometer) DEM (Digital Elevation Model) satellites inmost of the selected glacier areas. However, they largely differ to previous GRACE-based studies which weattribute to our different post-processing techniques of the newer GRACE data. In addition, we explicitlyshow regional mass change features for both the interannual glacier mass changes and the 14-a averagedseasonal glacier mass changes. These changes can be explained in parts by total net precipitation (netsnowfall and net rainfall) and net snowfall, but mostly by total net radiation energy when compared to datafrom the ERA5-Land meteorological reanalysis. Moreover, nearly all the non-trend interannual masschanges and most seasonal mass changes can be explained by the total net radiation energy data. The massloss trends could be partly related to a heat effect due to increased net rainfall in Tianshan Mountains, QilianMountains, Nyainqentanglha Mountains and Eastern Himalayas. Our new results for the glacier mass changein this study could help improve the understanding of glacier variation in the HMA area and contribute tothe study of global change. They could also serve the utilization of water resources there and in neighboringareas.

Morphology and biology of Cyclops scutifer Sars, 1863 in high mountain lakes of East Siberia (including Lake Amut)

Data on zooplankton from 13 high-mountain lakes of East Siberia have shown that the Holarctic copepod Cyclops scutifer Sars,1863 dominates among crustaceans.In July,its abundance comprised 64%-98%of the total plankton fauna in the pelagial of these lakes,approximately 30%in the littoral zone and10%in small northern thermokarst lakes.Biometric measurements and morphological descriptions based on scanning microscope images are supplemented by the data on its geographic distribution and phenology.

Phytogeographic and Syntaxonomic Diversity of High Mountain Vegetation in Dinaric Alps (Western Balkan,SE Europe)

The high alpine and subalpine vegetation of Dinaric Alps is very diverse. These are conditional on genuine patterns of development of the geological substrate, climate, soil and terrain on the mountain world, which are interconnected and spatially, and ecologically away. Also, today high mountain vegetation is extremely important indicator of global changes. In this area are many refugia of glacial biodiversity. Very illustrative example for understanding the specific forms of ecological diversity is high alpine vegetation in the area of the Balkan Peninsula. Vegetation of alpine belt of Western Balkans and Bosnia and Herzegovina is differed by extremely high level of biological and ecological diversity. Climatogenous vegetation are alpine and sub-alpine pastures above of timberline, then extra zonal forms of vegetation - glaciers, rock creeps, breaches of rocks, alpine springs, marsh, and tall greenery. This vegetation is dominant determinant of alpine ecosystems that creates their unique physiognomy and also enables prime production of biomass. It is different with extraordinary floral richness, especially in a number of endemic species and glacier relicts that are included in a large number of phytocoenoses, many of which are of endemic. In syntaxonomic sense, alpine vegetation is differentiated into lo classes： Elyno- Seslerietea, Juncetea trifidi, Salicetea herbaceae,Thalspietea rotundifolii, Asplenietea trichomanis, and Scheuchzerio-Caricetea fuscae, Montio- Cardaminetea, Loiseleurio-Vaccinietea, Mulgedio- Aconitetea and Molinio-Arrhenatheretea. These classes are differentiated into ao vegetation orders, 38 alliances and 19o associations and sub-associations. In total, that is 6o % of communities of total vegetation diversity of Bosnia and Herzegovina, and 12.5% of classes of highest syntaxonomic categories in vegetation diversity of Europe.

Long-term changes and periodicity of ice phenomena in the high mountain Lake Morskie Oko(Tatra Mountains,Western Carpathians)

High montain lakes are regarded as sensitive indicators of environmental changes in local and global scales.In recent years,climate change has considerablely influenced the timing of ice phenomena in these lakes.The objective of the paper is an investigation of long-term changes and periodicity of ice phenomena in high mountain Lake Morskie Oko(1392.8 m a.s.l.)located in the Tatra Mts.in the period 1971-2020.The study employed the Lomb-Scargle periodogram,linear regression modelling for temporal trends,correlation analysis,parameters of variability,and flashiness index.Periodicity of the duration of ice phenomena(~5.4 y)and ice cover on the lake(~13.5 y)was observed,although both are statistically insignificant.Ice cover duration has been interrupted several times by winter thaws after 1996 whereas no such events had been reported earlier.The trend towards a delayed appearance of ice phenomena reaches 4.0 d·decade^(-1)(p<0.001).The observed trend towards an earlier ice phenomena disappearance reaches 5.1 d·decade^(-1)(p<0.001).It results in a decline of the number of days with ice phenomena on Lake Morskie Oko at a rate of 9.0 d·decade^(-1)(p<0.001).The duration of ice cover on Lake Morskie Oko has been decreasing at a rate of 10.4 d·decade^(-1).It is attributed to later freezeup(3.9 d·decade^(-1),p<0.001)and earlier ice break-up(5.6 d·decade^(-1),p<0.001).An increasing trend of average annual air temperature(0.4°C·decade^(-1),p<0.001)in the period 1971-2020 is observed.A statistically significant correlation is recorded between ice phenomena and ice cover(beginning,end,duration),average annual air temperature,average air temperature of three summer months(June,July,August),and average air temperature of the six months period from June to November.Higher air temperature induces growing heat resources accumulated in the lake water in the summer and autumn seasons,potentially causing later initiation of ice phenomena in the lake.There is no statistically significant relationship between maximum ice thickness and any air temperature parameters.Variability of maximum ice thickness appears to have been significantly increasing in the second part of the investigated period(1996-2020).

Spatial variability between glacier mass balance and environmental factors in the High Mountain Asia

High Mountain Asia(HMA) region contains the world’s highest peaks and the largest concentration of glaciers except for the polar regions, making it sensitive to global climate change. In the context of global warming, most glaciers in the HMA show various degrees of negative mass balance,while some show positive or near-neutral balance. Many studies have reported that spatial heterogeneity in glacier mass balance is strongly related to a combination of climate parameters. However, this spatial heterogeneity may vary according to the dynamic patterns of climate change at regional or continental scale. The reasons for this may be related to non-climatic factors. To understand the mechanisms by which spatial heterogeneity forms, it is necessary to establish the relationships between glacier mass balance and environmental factors related to topography and morphology. In this study, climate, topography,morphology, and other environmental factors are investigated. Geodetector and linear regression analysis were used to explore the driving factors of spatial variability of glacier mass balance in the HMA by using elevation change data during 2000–2016. The results show that the coverage of supraglacial debris is an essential factor affecting the spatial heterogeneity of glacier mass balance, followed by climatic factors and topographic factors, especially the median elevation and slope in the HMA. There are some differences among mountain regions and the explanatory power of climatic factors on the spatial differentiation of glacier mass balance in each mountain region is weak, indicating that climatic background of each mountain region is similar. Therefore, under similar climatic backgrounds, the median elevation and slope are most correlated with glacier mass balance. The interaction of various factors is enhanced, but no unified interaction factor plays a primary role. Topographic and morphological factors also control the spatial heterogeneity of glacier mass balance by influencing its sensitivity to climate change. In conclusion,geodetector method provides an objective framework for revealing the factors controlling glacier mass balance.

Degradation of High Mountain Ecosystems in Northern Europe

Data material of a long-term high mountain ecosystem research project was used to interpret thegrazing impact of reindeers. In central Norwayinvestigations were conducted to both, areas wherereindeer grazing is excluded, and areas whereintensive pasturing is present for a long period oftime. The comparative analysis of grazing impact was based on similar environmental conditions. Theresults were transposed to northern Norway wheredramatic overgrazing had been exceeding thecarrying capacity. Using landscape ecologicalmappings, especially of vegetation and soils, theimpact of reindeer grazing in different areas becameobvious. Non-grazed lichen-dominated ecosystems of the snow-free locations functioned sensitively nearthe limit of organism survival. These localities weremost influenced by grazing as they offer the winterforage to the reindeers. So, intensive grazing incentral Norway led to landscape degradation bydestruction of the vegetation and superinduced bysoil erosion. Those features were comparable to thesituation in northern Norway, where a broad-scale destruction of the environment combined with adepression of the altitudinal belts had occurred dueto overgrazing. Functioning principles of intact high mountain systems were explained and used to interpret theenvironmental background for the understanding ofdegradation phenomena. Finally, the use of a newmodel calculating the carrying capacity of high mountain landscape was discussed.

Altitudinal Levels and Altitudinal Limits in High Mountains

In lowlands climate-specific processes due to weathering and erosion are dominant, whilst the geomorphology of mountains is dependent on the geologic-tectonic structure, i.e., the energy of erosion that increases according to the vertical. The expression ＂extremely high mountains＂ has been established as the extreme of a continuous mountain classification. It has to be understood in terms of geomorphology, glaciology and vegetation. Correspondence of the planetary and hypsometric change of forms is of great value as synthetic explanation. It is confirmed with regard to vegetation, periglacial geomorphology and glaciology. Due to the world-wide reconstruction of the snowline its paleoclimatie importance increases, too. Apart from lower limits the periglacial and glacial altitudinal levels also show zones of optimum development and climatic upper limits in the highest mountains of the earth. According to the proportion of the altitudinal levels a classification as to arid, temperate and humid high mountains has been carried out.

A STUDY ON THE ECOLOGICAL CLIMATES OF SOME FAMOUS TEA GROWING AREAS IN HIGH MOUNTAINOUS REGIONS OF CHINA

The tea tree [Camellia sinensis (L) Kuntze] is one of the world’s economic crops. It is an especially important crop for southern China. Environmental factors related to the tea yield and quality in some high mountain areas of China are identified in this paper. These factors are: geology, topography, climate, hydrology, soil and vegetation. Climatological factors are the most important. Using data collected from meteorological stations which are situated at the summit and the base of high mountains, this paper discusses ecological climatic problems in growing tea in China. The ecological climatic characteristics of the famous tea areas mainly included are as follows: more . amounts of clouds and fog, less percentage of sunshine, abundant rainfall and high relative humidity in the air, temperatures that rise and fall slowly, daily and annual temperature ranges that are smaller, more days that are suitable for tea growing and low wind speeds in the lee-sides and valleys of mountains. All of these

Disaster effects of climate change in High Mountain Asia:State of art and scientific challenges Disaster effects of climate change in High Mountain Asia:State of art and scientific challenges

High Mountain Asia(HMA)shows a remarkable warming tendency and divergent trend of regional precipitation with enhanced meteorological extremes.The rapid thawing of the HMA cryosphere may alter the magnitude and frequency of nature hazards.We reviewed the influence of climate change on various types of nature hazards in HMA region,including their phenomena,mechanisms and impacts.It reveals that:1)the occurrences of extreme rainfall,heavy snowfall,and drifting snow hazards are escalating;accelerated ice and snow melting have advanced the onset and increased the magnitude of snowmelt floods;2)due to elevating trigger factors,such as glacier debuttressing and the rapid shift of thermal and hydrological regime of bedrock/snow/ice interface or subsurface,the mass flow hazards including bedrock landslide,snow avalanche,ice-rock avalanches or glacier detachment,and debris flow will become more severe;3)increased active-layer detachment and retrogressive thaw slumps slope failures,thaw settlement and thermokarst lake will damage many important engineering structures and infrastructure in permafrost region;4)multi-hazards cascading hazard in HMA,such as the glacial lake outburst flood(GLOF)and avalanche-induced mass flow may greatly enlarge the destructive power of the primary hazard by amplifying its volume,mobility,and impact force;and 5)enhanced slope instability and sediment supply in the highland areas could impose remote catastrophic impacts upon lowland regions,and threat hydropower security and future water shortage.In future,ongoing thawing of HMA will profoundly weaken the multiple-phase material of bedrock,ice,water,and soil,and enhance activities of nature hazards.Compounding and cascading hazards of high magnitude will prevail in HMA.As the glacier runoff overpasses the peak water,low flow or droughts in lowland areas downstream of glacierized mountain regions will became more frequent and severe.Addressing escalating hazards in the HMA region requires tackling scientific challenges,including understanding multiscale evolution and formation mechanism of HMA hazard-prone systems,coupling thermo‒hydro‒mechanical processes in multi-phase flows,predicting catastrophes arising from extreme weather and climate events,and comprehending how highland hazards propagate to lowlands due to climate change.

Integrated approach of predicting rock stability in high mountain valley underground caverns

High mountain valleys are characterized by the development of intricate ground stress fields due to geological processes such as tectonic stress,river erosion,and rock weathering.These processes introduce considerable stability concerns in the surrounding rock formations for underground engineering projects in these regions,highlighting the imperative need for rigorous stability assessments during the design phase to ensure construction safety.This paper introduces an innovative approach for the pre-evaluation of the stability of surrounding rocks in underground caverns situated within high mountain valleys.The methodology comprises several pivotal steps.Initially,we conduct inverse calculations of the ground stress field in complex geological terrains,combining field monitoring and numerical simulations.Subsequently,we ascertain stress-strength ratios of the surrounding rocks using various rock strength criteria.To assess the stability characteristics of the surrounding rocks in the 1^(#)spillway cave within our project area,we employ numerical simulations to compute stress-strength ratios based on different rock strength criteria.Furthermore,we undertake a comparative analysis,utilizing data from the 5^(#)Underground Laboratory(Lab 5)of Jinping II Hydropower Station,aligning the chosen rock strength criterion with the damage characteristics of Lab 50s surrounding rocks.This analysis serves as the cornerstone for evaluating other mechanical responses of the surrounding rocks,thereby validating the pre-evaluation methodology.Our pre-evaluation method takes into account the intricate geological evolution processes specific to high mountain valleys.It also considers the influence of the initial geostress field within the geological range of underground caverns.This comprehensive approach provides a robust foundation for the analysis and assessment of the stability of surrounding rocks,especially in high mountain valley areas,during the design phase of underground engineering projects.The insights derived from this analysis hold substantial practical significance for the effective guidance of such projects.

Spatial differences of ice volume across High Mountain Asia

Advanced knowledge of glacier ice volume is vital for water resource assessment.Previous studies have focused on the estimation of ice volume,but the quantitative understanding of the spatial variability of ice volume across High Mountain regions is currently lacking.Here,we used global-scale ice thickness,debris cover and equilibrium line data to analyse ice-volume differences at various scales across High Mountain Asia(HMA).The results showed that 6.3%of the HMA glaciers are covered by debris,with debris area and volume accounting for 9%and 13.8%of the total glacier area and volume,respectively.An average debris-cover volume ratio of 13%was observed.The spatial distribution of ice volume across the HMA varies considerably from region to region.The ice volume is predominately distributed on north-facing slopes and accounts for approximately 38%of the total.It is very common in Altay and Sayan,East Tian Shan,West Kunlun,East Kunlun and Qilian Shan.Meanwhile,ice volumes in the Himalayas and Hengduan Shan are mainly distributed on the southeast aspect.Relative weight functions showed that glacier area,maximum length and average thickness are closely related to ice volume,with average relative weights of 63.7%,22.5%and 9.8%,respectively.This study is important for the evolution of glacier volume and water resource assessment.

Changes in equilibrium-line altitude and implications for glacier evolution in the Asian high mountains in the 21st century

In the context of global warming,glaciers in the Asian High Mountains(AHMs)are shrinking at an accelerating rate.Projecting their future change is helpful for understanding the hydrological and climatic effects related to glacier retreat.Here,we projected glacier change in the AHMs from 1979 to 2100 under shared socioeconomic pathway(SSP)scenarios from the perspective of temperature,equilibrium-line altitude(ELA),and accumulation area.The annual mean temperature in the AHMs increased by 1.26℃ from 1979 to 2014,corresponding to an increase of 210 m in the mean ELA and a decrease of 1.7×10^(4)km^(2) in the glacier accumulation area.Under the SSP2-4.5(SSP5-8.5)scenario,the annual mean temperature in the AHMs would increase by 2.84℃(3.38℃)in 2040–2060 relative to that in 1850–1900,leading to the mean ELA reaching an elevation of5661 m(5777 m).The accumulation area in the AHMs decreased by 46.3%from 1995 to 2014 and was projected to decrease by60.1%in 2040–2060.Moreover,the annual mean temperature in the AHMs was projected to increase by 3.76℃(6.44℃)in2080–2100 relative to that in 1850–1900,corresponding to the ELA reaching an elevation of 5821 m(6245 m)and the accumulation area decreasing to 1.8×10^(4)km^(2)(0.5×10^(4)km^(2)).These data suggest that the conditions for glacier development will disappear in most of the AHMs,except for extreme high-altitude regions in the Tianshan,Pamir,and Himalaya Mountains.Under the SSP2-4.5(SSP5-8.5)scenario,when the global mean temperature increases 1.5℃(2℃)above pre-industrial levels,the annual mean temperature will increase by 2.12℃(2.86℃)and the accumulation area will decrease by 15%(48%)in the AHMs compared with that in 1995–2015.Therefore,a 1.5℃ increase in global warming would keep 40%more of the glacial accumulation area(1.5×10^(4)km^(2))in the AHMs compared to a 2℃ increase in global warming.

Constructing dataset of classified drainage areas based on surface water-supply patterns in High Mountain Asia

The High Mountain Asia(HMA)region,ranging from the Hindu Kush and Tien Shan in thewest totheHimalaya inthe southwith an altitude between 2000 and 8844 m,holds the largest reservoir of glaciers and snow outside Earth Polar Regions.In the last decades,numerous glaciers and lake areas there have undergone tremendous changes with water redistribution.In order to increase understanding of the pattern of distribution of water resources,and their dynamic changes at the basin scale,a watershed classification based on the water replenishment patterns dataset was constructed.The input dataset are from the Randolph Glacier Inventory V.6.0 and the vector data of rivers and streams.Four datasets were thus obtained:Glacier-fed and Runoff-fed Drainage Area(GRDA),Glacier-fed and Runoff-free Drainage Area(GDA),Glacier-free and Runoff-fed Drainage Area(RDA),and the Glacier-free and Runoff-free Drainage Area(NGRDA),and the numbers of these four types of basins are 87,107,32,and 448 separately.The statistical results show GRDA has the largest surface area,accounting for 82.2%of the total basin area in HMA,mainly in the region of the basin with outflow rivers or streams.Dominated by small basins,the GDA area accounts for the smallest area,only 3.86%and the RDA accounts for 5.62%.For NGRDA,most are with small areas,accounting for 8.32%,and mainly distributes in the closed basin of the Qiangtang Plateau.This dataset provides a fundamental classified data source for research on water resources,climate,ecology,and environment in HMA.The published data are available at https://data.4tu.nl/download/uuid:d07d748f-d10b-4308-9626-199ef05cc9af/and http://www.dx.doi.org/10.11922/sciencedb.923.

1991-2020 climate normal in the European Alps:focus on high-elevation environments

Alps are an important geographical area of the European continent and,in this area,temperature increase is most evident.However,the 1991-2020 climate normal in the Alps has still not been thoroughly investigated.Aiming to fill this gap with a focus on high-elevation environments,minimum and maximum daily air temperature acquired by 23 automatic weather station were used.The results show that the mean annual values of minimum and maximum temperature for the 1991-2020 climate normal in the Alps are-2.4℃ and 4.4℃,respectively,with a warming rate of 0.5℃/10 years.The mean annual temperature comparison between 1961-1990 and 1971-2000,1961-1990 and 1981-2010,1961-1990 and 1991-2020 climate normal show an increase of 0.3℃,0.5℃ and 0.9℃,respectively.The results also confirm that seasonal and annual temperatures are rising through the whole Alpine arc,mainly in summer and autumn.This work highlights that annual minimum and maximum temperature do not seem to be affected by a positive elevation-dependent warming.Instead,a positive elevation-dependent warming in the maximum values of the annual minimum temperature was found.If anthropogenic emissions maintain the trend of the last decades,the expected mean annual temperature of the 2001-2030 climate normal is-0.2℃,with an increase of 0.5℃ if compared to the 1991-2020 climate normal and with an increase of 1.5℃ if compared to the 1961-1990 climate normal.This study highlights the warming rate that is now present in the European Alps,provides indications on the warming rate that will occur in the coming years and highlights the importance of carrying out investigations that consider not only the last 30-year climate normal,but also the most recent 30-year climate normal by comparing them with each other.

Establishment of Safety Guarantee System of Mountainous Tourism——A Case Study of High and Higher Mountains

After summarizing researches on domestic and foreign tourism safety,it was found that there were few research results on mountainous tourism safety,especially tourism safety and tourism safety guarantee system of high and higher mountains with high risk.The paper had concluded hidden dangers and sources of safe accidents of mountainous tourism,and studied tourism safety guarantee system of high and higher mountains.Furthermore,it proposed that tourism safety guarantee system was composed of tourism safety policies and regulations,tourism precaution,tourism safety control,tourism safety rescue and tourism insurance;and finally pointed out components of each factor.

Analysis of Fragmentation Processes in High-Mountain Forests of the Centre of Mexico

High-mountain forests (>3500 masl) are the main supplier of environmental services to Mexico City and its metropolitan area. Taking as a study case the Nevado de Toluca National Park, this article focuses on the considerable reduction on the density of its forest cover, characterised by disturbances in the structure and dynamics of Pinus hartwegii. This specie is located towards the upper limits of the altitudinal gradient (3500 - 4100 masl) constituting the only pine species in the world capable to be established in those extreme environmental conditions. The information was collected through the implementation of 30 Sampling Plots (SP) of 20 × 50 mts (1000 m2) in three forest density categories: dense, semi-dense and fragmented. For each forest category, all trees ≥2.5 cm DBH were measured in 10 SPs. The measurement variables were DBH, total and commercial height, forest health and forest extraction. The results show the abundance of dense, semi-dense and fragmented forest (336, 202 and 150 trees/Ha-1), with extraction percentages of 11%, 20% and 33% respectively. The horizontal structure distribution shows the shape of an inverted J for the three conditions. However, the phytosanitary conditions of the semi-dense forests (83% infested trees) and fragmented (63% infested trees), do not guaranties the survival of the adult trees, implying an intensification of the fragmentation process for the next decade;given the reduction of the regeneration patterns due to the lack of healthy tree breeding.

Industrial Poverty Alleviation Model in Southwestern High-altitude Mountainous Areas of China——A Case Study of Industrial Poverty Alleviation of Xueshan Township in Luquan County of Yunnan Province through Planting Codonopsis pilosula

Due to the severe restrictions of natural conditions and ecological environment,high-altitude mountainous areas usually become the " hard bones" in the battle against poverty. Xueshan Township,Luquan Yi and Miao Autonomous County of Yunnan Province,located in the alpine valley of Jinsha River,is a major township with wide and deep poverty,and the incidence of poverty is up to 45. 00%. In recent years,Xueshan Township has insisted on the battle against poverty,made effort to develop the Codonopsis pilosula industry,and successfully developed a road to poverty alleviation through C. pilosula industry,and formed a unique industrial poverty alleviation model by the end of 2018,the incidence of poverty dropped to 0. 74%. Based on field survey and interview,this paper analyzes and summarizes the specific practices,main results,practical experience and promotion and application measures of the poverty alleviation model of C. pilosula planting industry in Xueshan Township,in the hope of providing certain reference for the targeted poverty alleviation in similar areas in Yunnan Province and other provinces of China.