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Laohugou glacier No. 12 (LHG12), located in the northeast of the Qinghai–Tibet Plateau, is the largest valley glacier in the Qilian mountains. Since 1957, LHG12 has shrunk significantly. Due to the limitations of in situ observations, simulations and investigations of LHG12 have higher levels of uncertainty. In this study, consumer-level, low-altitude microdrones were used to conduct repeated photogrammetry at the lower part of LHG12, and a digital orthophoto map (DOM) and a digital surface model (DSM) with a resolution at the centimeter scale were generated, from 2017 to 2021. The dynamic parameters of the glacier were detected by artificial and automatic extraction methods. Using a combination of GNSS and drone-based data, the dynamic process of LHG12 was analyzed. The results show that the terminus of LHG12 has retreated by 194.35 m in total and by 19.44 m a−1 on average during 2008–2021. The differential ablation leading to terminus retreat distance markedly increased during the study period. In 2019–2021, the maximum annual surface velocity was 6.50 cm day−1, and during ablation season, the maximum surface velocity was 13.59 cm day−1, 52.17% higher than it is annually. The surface parameters, motion, and mass balance characteristics of the glacier had significant differences between the west and east branches. The movement in the west branch is faster than it is in the east branch. Because of the extrusion of the two ice flows, there is a region with a faster surface velocity at the ablation area. The ice thickness of LHG12 is decreasing due to intensified ablation, leading to a deceleration in the surface velocity. In large glaciers, this phenomenon is more obvious than it is in small glaciers in the Qilian mountains. [ABSTRACT FROM AUTHOR]

The long-term change of evapotranspiration (ET) is crucial for managing water resources in areas with extreme climates, such as the Tibetan Plateau (TP). This study proposed a modified algorithm for estimating ET based on the MOD16 algorithm on a global scale over alpine meadow on the TP in China. Wind speed and vegetation height were integrated to estimate aerodynamic resistance, while the temperature and moisture constraints for stomatal conductance were revised based on the technique proposed by Fisher et al. (2008). Moreover, Fisher’s method for soil evaporation was adopted to reduce the uncertainty in soil evaporation estimation. Five representative alpine meadow sites on the TP were selected to investigate the performance of the modified algorithm. Comparisons were made between the ET observed using the Eddy Covariance (EC) and estimated using both the original and modified algorithms. The results revealed that the modified algorithm performed better than the original MOD16 algorithm with the coefficient of determination (R 2 ) increasing from 0.26 to 0.68, and root mean square error (RMSE) decreasing from 1.56 to 0.78 mm d −1 . The modified algorithm performed slightly better with a higher R 2 (0.70) and lower RMSE (0.61 mm d −1 ) for after-precipitation days than for non-precipitation days at Suli site. Contrarily, better results were obtained for non-precipitation days than for after-precipitation days at Arou, Tanggula, and Hulugou sites, indicating that the modified algorithm may be more suitable for estimating ET for non-precipitation days with higher accuracy than for after-precipitation days, which had large observation errors. The comparisons between the modified algorithm and two mainstream methods suggested that the modified algorithm could produce high accuracy ET over the alpine meadow sites on the TP. [ABSTRACT FROM AUTHOR]

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

The Thornthwaite moisture index, an index of the supply of water (precipitation) in an area relative to the climatic demand for water (potential evapotranspiration), was used to examine the spatial and temporal variation of drought and to verify the influence of environmental factors on the drought in the Hengduan Mountains, China. Results indicate that the Thornthwaite moisture index in the Hengduan Mountains had been increasing since 1960 with a rate of 0.1938/yr. Annual Thornthwaite moisture index in Hengduan Mountains was between -97.47 and 67.43 and the spatial heterogeneity was obvious in different seasons. Thornthwaite moisture index was high in the north and low in the south, and the monsoon rainfall had a significant impact on its spatial distribution. The tendency rate of Thornthwaite moisture index variation varied in different seasons, and the increasing trends in spring were greater than that in summer and autumn. However, the Thornthwaite moisture index decreased in winter. Thornthwaite moisture index increased greatly in the north and there was a small growth in the south of Hengduan Mountains. The increase of precipitation and decrease of evaporation lead to the increase of Thornthwaite moisture index. Thornthwaite moisture index has strong correlation with vegetation coverage. It can be seen that the correlation between Normalized Difference Vegetation Index (NDVI) and Thornthwaite moisture index was positive in spring and summer, but negative in autumn and winter. Correlation between Thornthwaite moisture index and relative soil relative moisture content was positive in spring, summer and autumn, but negative in winter. The typical mountainous terrain affect the distribution of temperature, precipitation, wind speed and other meteorological factors in this region, and then affect the spatial distribution of Thornthwaite moisture index. The unique ridge-gorge terrain caused the continuity of water-heat distribution from the north to south, and the water-heat was stronger than that from the east to west part, and thus determined the spatial distribution of Thornthwaite moisture index. The drought in the Hengduan Mountains area is mainly due to the unstable South Asian monsoon rainfall time. [ABSTRACT FROM AUTHOR]

Cryoconite deposited on mountain glacier surfaces is significant for understanding regional atmospheric environments, which could influence the albedo and energy balance of the glacier basins, and maintain the glacial microbiology system. Field observations were conducted on the glaciers of western China, including Laohugou Glacier No.12 (LHG), Tanggula Dongkemadi Glacier (TGL), Zhadang Glacier (ZD), and Baishui Glacier No.1 in the Yulong Mountains (YL), as well as Urumqi Glacier No.1 in the Tianshan Mountains (TS) for comparison with locations in the Tibetan Plateau, in addition to laboratory TEM-EDX analysis of the individual cryoconite particles filtered on lacey carbon (LC) and calcium-coated carbon (Ca-C) TEM grids. This work provided information on the morphology and chemical composition, as well as a unique record of the particle’s physical state, of cryoconite deposition on the Tibetan Plateau. The result showed that there is a large difference in the cryoconite particle composition between various locations on the Tibetan Plateau. In total, mineral dust particles were dominant (>50%) in the cryoconite at all locations. However, more anthropogenic particles (e.g., black carbon (BC) and fly ash) were found in YL (38%) and ZD (22%) in the Ca-C grids in the southern locations. In TGL, many NaCl and MCS particles (>10%), as well as few BC and biological particles (<5%), were found in cryoconite in addition to mineral dust. In TS, the cryoconite is composed primarily of mineral dust, as well as BC (<5%). Compared with other sites, the LHG cryoconite shows a more complex composition of atmospheric deposition with sufficient NaCl, BC, fly ash and biological particles (6% in LC grid). The higher ratio of anthropogenic particles in the southern Tibetan Plateau is likely caused by atmospheric pollutant transport from the south Asia to the Tibetan Plateau. Cryoconite in the northern locations (e.g., TGL, LHG, and TS) with higher dust and salt particle ratio are influenced by large deserts in central Asia. Therefore, the transport and deposition of cryoconite is of great significance for understanding regional atmospheric environment and circulation. Large amounts of biological, NaCl and MCS particles were observed in the cryoconite, implying that in addition to dust and BC, many types of light absorbing impurities (LAI) together could influence the glacier albedo change and induce ice melting in the mountain glaciers of the Tibetan Plateau. Moreover, a high BC concentration in the south (e.g., YL and ZD) could significantly change the albedo of snow and ice, at a greater rate than dust, causing significant melting of the glaciers under global warming. [ABSTRACT FROM AUTHOR]

To better understand the risk of disasters due to glacial lake outburst floods (GLOFs), we synthetically analyze the spatial distribution and evolution of moraine-dammed lakes and potentially dangerous glacial lakes (PDGLs) in the Chinese Himalaya. Our county-based assessment of GLOF disaster risk combines PDGL outburst hazard, regional exposure, vulnerability of exposed elements and adaptation capability (risk management) using the analytic hierarchy process. We synthetically analyze the disaster risk using the weighted comprehensive method. Remote-sensing data show there are 329 moraine-dammed lakes (>0.02km2; total area 125.43km2) in the Chinese Himalaya, of which 116 (total area 49.49 km2) are identified as PDGLs. The zones at highest risk of GLOF disaster are mainly located in Nyalam, Tingri, Dinggyê, Lhozhag, Kangmar and Zhongba, in the mid-eastern Himalaya. Lowest-risk zones are located in the eastern Himalaya. On the county scale, Lhozhag and Lhunze have the highest hazard degrees and exposure, while Zhongba and Zando have the highest degree of vulnerability and lowest adaptation capacity. Our regionalization results for GLOF disaster risk are consistent with the distribution of historical disaster sites across the Chinese Himalaya. [ABSTRACT FROM AUTHOR]

Wind-blown dust derived from the arid and semi-arid regions is an important atmospheric component affecting the Earth's radiation budget. Dust storms are prevailing in central Asia. Deposition of atmospheric dust in snow was measured on Glacier No.12 (5040 m a.s.l.) in the Laohugou Basin and Shiyi Glacier (4510 m a.s.l.) in the Yeniugou Basin, of western Qilian Mountains, China, mainly focusing on dust concentration and size distribution, chemistry, SEM-EDX analysis and Nd-Sr isotopic composition. An analysis of spatial distribution of dust concentration and size distribution in the snow cover at two sites suggests that deposition of dust in western Qilian Mountains is different between sites as the environment changes from west to east. Mean mass concentration of dust with 0.57 < d<40 µm in the snow is 3461 µg kg-1 on Glacier No.12 and 2876 µg kg-1 on Shiyi Glacier, respectively. Annual flux of dust deposition to western Qilian Mountains has a range of 143.8-207.6 µg cm-2 yr-1 for particles with 0.57 < d<40 µm. Dust layers in the snowpit contain Ca- and Na-rich materials typically found in Asian dust particles. Number-size distribution indicated that most of the dust diameter is <2.0 µm, implying the significant influences of finer particles to alpine glacier regions of central Asia. Volume size distributions of dust particles showed single-modal structures having volume median diameters from 3 to 22 µm, which is comparable to the results of dust deposition on glaciers of the adjacent Tianshan Mountains in western China. SEM-EDX analysis suggested that dust particles were mainly composed of mineral particles, besides some fly ash particles and soot. EDX shows that mineral particles contain Si-, Al-, Ca-, K-, and Fe-rich materials, such as quartz, albite, aluminate, etc. The Nd-Sr isotopic composition of insoluble particles in two glaciers showed that Badain Jaran Desert and Qaidam Basin were the most possible source regions of dust in the western Qilian Mountains. Physicochemical constituents of dust indicated that the snowpack was influenced by both local atmospheric environment, e.g. local dust, and anthropogenic activities in central Asia. [ABSTRACT FROM AUTHOR]

The glacier ELA is one of the important parameters reflecting climate change. Based on observations of the equilibrium line altitude (ELA) of Urumqi Glacier No.1 in the Tianshan Mountains, we established a statistical model between ELA and its major influencing factors, warm season air temperature (air temperature averages for May, June, July and August) and annual precipitation. Result showed that, warm season air temperature was the leading climatic factor influencing ELA variations. The glacier ELA ascends (descends) 61.7 m when warm season air temperature increases (decreases) by 1°C, and ascends (descends) 13.1 m when cold season precipitation decreases (increases) by 10%. In the period 1959-2008, the glacier ELA showed a general increasing trend, ascending108 m and reaching its highest altitude in 2008 at 4168 m a.s.l., close to the glacier summit. If future climate is similar to that in the past 50 years, the ELA of Urumqi Glacier No.1 will still ascend with a speed of 2.16 m/a. However, If future climate is similar to that in the period 2000-2008, the ELA will still ascend with a speed of 6.5 m/a before it is stable. As a result of ELA variation, the accumulation area ratio (AAR) of the glacier showed a decreasing trend during the past 50 years. [ABSTRACT FROM AUTHOR]

As typical inland river basins in China, the Ürümqi River Basin and the Aksu River Basin were selected as study areas in this paper. In the past several decades, the climate has had a tendency to change from warm-drying to warm-wetting, with a coinstantaneous response by mountain glacier meltwater of these areas. Comparing questionnaire survey data with scientific observation, this study focused on the character of public perception on climate and cryosphere changes, the changes' possible impacts on water resources, and adaptation measure choices by the public. Results presented in this study showed that: 1) Perceptions of most respondents on climate and cryosphere changes conform to objective facts, but some of them still have suspicion relating to these environmental changes; 2) Even though increasing precipitation and glacier meltwater has caused an increased water supply, due to the increasing demand of the unit area water for agriculture (industrial and living water demand may be involved), water shortage is still a big problem in sustainable development. Because of unemployment or the inconspicuous benefits of water-saving measures, the wasting of water resources may be a serious problem in these areas; 3) Most people preferred to choose the adaptation measures implemented by government and policy-making departments. Some people showed more preference for measures avoiding unfavorable natural environmental consequences. Public perceptions on the urgency of individual participation are still inadequate. Some of the measures should be communicated broadly and warmly encouraged; 4) Public choices of adaptation measures for climate and cryosphere change are impacted by demographic factors such as age, gender, region, nationality, education and occupation. The impacts of such factors are complicated. [ABSTRACT FROM AUTHOR]

Abstract: The structural, salinity and stable oxygen-isotopic properties of multi-year landfast sea-ice samples collected from Nella Fjord, East Antarctica were used to determine the ice formation process and the fractional contribution of snow, in both snow ice and superimposed ice, to the total sea-ice thickness. The textural analysis of the sea-ice cores revealed a general structure of a granular surface layer, horizontal c-axis in the columnar ice and, in some cases, a “buried” granular-ice layer at depth between two columnar-ice layers. The textural and isotopic properties of the ice core samples indicate that thermodynamic mechanisms alone are responsible for the development of the multi-year fast ice in the region investigated. Superimposed ice contributed 5% to the ice thickness at some sites. Using a mid-range isotopic criterion to distinguish between snow ice and frazil ice in the granular layers, we estimate that snow-ice layers contributed 38% of the total ice thickness in the samples. The actual fraction of snow in the granular-ice layers in different cores was from 1% to 24% of the total sea-ice thickness. [Copyright &y& Elsevier]

Mount Everest, the highest point on the Earth is often referred to as the earth's third pole as such the place is relatively inaccessible and little is known about its meteorology. In April 2005, an automatic weather station was installed at the mountain's North Col (6523 m a. s. I.). According to the observational 10-minute mean and daily records, the meteorological characteristics were analyzed. All the meteorological elements displayed obvious diurnal variations during May 1 to July 22, 2005. The monthly variation of daily meteorological elements on Mount Everest coincided with that on Dingri, the closest routine meteorological station, with the high correlation coefficients of 0.928, 0.877, 0.682, 0.755, 0.826 and 0.676 (n = 83, p < 0.001) for mean temperature, minimum temperature, maximum temperature, relative humidity, pressure and wind speed, respectively. Furthermore, the vertical mean gradient of temperature was above 0. 6°C /100 m, especially for the daily maximum temperature. Most weather events on Mount Everest prominently appeared on the same day as those on Dingri, especially those from daily mean pressure, temperature and relative humidity with the cross-correlation coefficients of 0. 673, 0. 485 and 0. 487 (n = 83, p < 0. 001), respectively. Some other weather events on Mount Everest lagged one-day behind those on Dingri. Furthermore, forecasting of the weather events on Mount Everest from pressure on Dingri was more reliable than those from the other meteorological elements. The conclusions are much important for research on meteorology and climate changes in the region. [ABSTRACT FROM AUTHOR]

A study is presented of the geographical distribution and spatial and temporal variabilities of the western China snow cover in the past 47 yr between 1951 and 1997. The data used consist of Scanning Multichannel Microwave Radiometer (SMMR) 6-day snow-depth charts, NOAA weekly snow extent charts, and the daily snow depth and number of snow cover days from 106 selected meteorological stations across western China. Empirical orthogonal function was performed on the SMMR dataset to better understand the spatial pattern and variability of the Qinghai–Xizang (Tibet) snow cover. A multiple linear regression analysis was conducted to show the association of interannual variations between snow cover and snow season temperature as well as precipitation. Further, the autoregressive moving average model was fitted to the snow and climate time series to test for their long-term trends. Results show that western China did not experience a continual decrease in snow cover during the great warming period of the 1980s and 1990s. It is of interest to note that no correlation was identified between temperature and precipitation in the snow cover season. However, year-to-year fluctuation of snow cover responds to both snowfall and snow season temperature. About one-half to two-thirds of the total variance in snow cover is explained by the linear variations of snowfall and snow season temperature. The long-term variability of western China snow cover is characterized by a large interannual variation superimposed on a small increase trend. The positive trend of the western China snow cover is consistent with increasing snowfall, but is in contradiction to regional warming. In addition, many constraints of the Qinghai–Xizang (Tibet) snow cover force the author’s challenge of Blanford’s hypothesis. [ABSTRACT FROM AUTHOR]

Annual mean discharge data of the five large rivers in the exorheic region of the Qinghai-Tibet Plateau from 1956 to 2000 are analyzed for trends with the Mann-Kendall nonparametric trend test. The results reveal that though in general no increasing trends exist in the total river discharges, significant regional differences of river discharge exist, reflecting the decreasing trends of discharge in the Yellow River and the Tongtian River (upper Changjiang River), an increasing trend in Yalong River, and inverted change in the Lancang River and Yarlung Zangbo River. Based on analyses of the seasonal discharge, it is found that climatic change had a significant effect on the seasonal variation of river discharge in the Qinghai-Tibet Plateau. In spring (from March to May) the discharge increased significantly, especially in the source area of the Yellow River. Together with the analyses on data of the mean temperature in the Northern Hemisphere and climatic data within the river basins, the relationship between discharges and mean temperature of the Northern Hemisphere is explored, which indicates that there is no increase in the stream discharge in the Qinghai-Tibet Plateau with global warming. It is probably the increasing evaporation, caused by rising temperature that offsets the hydrological effect of increasing precipitation. [ABSTRACT FROM AUTHOR]

Pyruvate is a light carboxylate in the troposphere and can act as potential cloud condensation nuclei. Due to its low concentrations, however, little work has been done on the species in precipitation. Past 43-year record of pyruvate was recovered from an ice core of Glacier 1 at 43°06'N and 86°49'E in the remote East Tianshan, northwestern China. It was revealed that pyruvate varied over a relatively large range with some below the detection limit, while part of it is so high as to be up to 70 ng · g-1. With an average concentration of 4. 1 ± 8.1 ng · g-1 (mean ± 1σ, N = 543), pyruvate is a minor species in comparison with other carboxylates. It is also low as compared with its precipitation in other parts of the world, suggesting a difference in its major source flux. The record revealed high pyruvate concentrations in the late halves of the 1950s and 1980s, but low in the late 1950s, late 1970s, and middle 1990s. The variation trend in the past 43 years is closely correlated with that of acetate, a major carboxylate from anthropogenic pollution to the atmosphere, indicating that tropospheric pyruvate in the remote area of northwestern China is probably a by-product in acetate formation. [ABSTRACT FROM AUTHOR]

Repeat measurements of glacier terminus positions show that glaciers in the central Himalayas have been in a continuous retreat situation in the past decades. The average retreat rate is 5.5-8.7 m/a in Mt. Qomolangma (Everest) since the 1960s and 6.4 m/a in Mt. Xixiabangma since the 1980s. In recent years, the retreat rate is increasing. Ice core studies revealed that the accumulation rate of glaciers has a fluctuating decrease trend in the last century with a rapid decrease in the 1960s and a relatively steady low value afterwards. Meteorological station record indicates that the annual mean temperature has a slow increase trend but summer temperature had a larger increase in the past 30 a. All these suggest that the glacier retreat results from precipitation decrease in combination with temperature increase, and hence glacier shrinkage in this region will speed up if the climatic warming and drying continues. [ABSTRACT FROM AUTHOR]

Examines the relation of the carbon isotope of tree-ring alpha-cellulose of Abies spectabibis collected from the southeastern Tibetan Plateau with climatic parameters. Effect of age trend and rising carbon dioxide; Reconstruction of the autumn relative humidity for the Nyinge region.

Studies recorded formate and acetate in a mid-latitude glacier in west China. Relationship of the occurrence of formate and acetate with processes in the biosphere; Average concentration of acetate and formate in the area; Formate to acetate ratio average.

Focuses on three ice cores recovered from the Himalayas (i.e. the East Rongbuk Glacier and the Far East Rongbuk Glacier at Mt. Qomolangma (Everest), and the Dasuopu Glacier at Xixiabangma), which show a sharp decline in the accumulation rates since the 1950s, which is consistent with the precipitation fluctuation over India and the low northern latitude zone (5°-35°N). Observation of an increasing trend for the ice core accumulations from the central and northern Qinghai-Tibetan Plateau (i.e. the Xiao Dongkemadi Glacier in the central Tanggula Mountains, the Guliya Ice Cap in the western Kunlun Mountains, and the Dunde Ice Cap in the Qilian Mountains) since the 1950s, which is consistent with the precipitation fluctuation over the middle-high northern latitude zone (35°-70°N); Significance of the variation magnitude of the high-elevation ice core accumulations; Extra sensitivity of high-elevation areas to climatic change; How the inter-decadal abrupt change of the African-Asian summer monsoon in the 1960s may attribute to the recent ice core accumulation change during the recent decades.

Light carboxylic acids are major chemical species in acidic precipitation, particularly in remote areas. They play a significant part in the acidification of the environment. Because the organic acids relate closely to the biosphere in the source, their records in snow and ice provide insight into the changes of paleoenvironment and biogeochemical cycles of C, H, O and S. However, the trace concentration of the acids plus their susceptibility to contamination and the exclusiveness of an analytical procedure to a specific instrument make the determination difficult. With DX-300 ion chromatography (IC), we developed a method with AS4A-SC as a separator, TAC-2 as a pre-concentrator installed in place of the sample loop, ATC-1 as an impurity trap installed before the injection valve, and ASRS-II as the suppressor that is regenerated in 25 mM H2SO4. Using gradient elution and Na2B4O7 solution as the eluent, the method resolves and quantitates within a single run of 14 min over 10 analytes from F−, CH3COO− to PO42−, SO42− and finally to (COO)22−. The relative errors for the anions are: F−, 2.6%; CH3COO−, 4%; HCOO−, 2%; CH3COCOO2−, 6%; methane sulfonate (MSA), 16.8%; Cl−, 3%; NO2−, 4%; NO3−, 2%; Br−, 4.5%; SO42−, 2%; and (COO)22−, 5.8%. [Copyright &y& Elsevier]

Ice core δ [sup 18]O records from the No. 1 glacier at the head of the Ür¨mqi River were used to characterize the relationship between δ [sup 18]O and contemporaneous surface air temperature (Ta) nearby the Daxigou Meteorological Station (3539 m above sea level, ∼2km away from the ice core drilling site). Although the ice core records of annually averaged δ [sup 18]O are positively correlated with contemporaneous surface air temperature, especially summer air temperature, the correlation is less significant than that for the precipitation samples due to depositional and post-depositional modification processes. However, the climatological significance of the ice core δ [sup 18]O records can be still preserved to a certain degree, which might extend the application of high altitude and sub-tropical ice core δ [sup 18]O records to paleoclimate reconstruction. [ABSTRACT FROM AUTHOR]

Presents information on a study which analyzed the major ions, lead and cadmium for snow-pit samples collected from the Arctic, the Qinghai-Tibetan Plateau and the Antarctic Ice Sheet. Uses of trace metals captured in permanent snow; Experimental procedure; Results and discussion.

Provides information on a study on the climatological significance of the net-accumulation record since 1954 as deduced from the top 10 m of the core at Mount Qomolangma (Everest). Sampling analysis processes; Results and discussion; Conclusion.

Discusses the spatial distribution and environmental significance of lead and its stable isotope in central Arctic snow. Comparison of the concentration of lead in the south section and in the north section; Anthropogenic lead; Main sources of lead.

Focuses on five enhanced summer monsoon events during the Last Interglaciation. Data from the carbon isotope record of organic matter from the Yuanbao loess section in China; How evidence of these events are recorded in paleosol layers, pollen assemblage and magnetic susceptibility; Suggestion the enhanced summer monsoon led to a shift in vegetation type, which is related to the change of δ13C value of organic matter in the paleosol layer; Suggestion that this value is a good indicator for summer monsoon variations; Implication for the mechanisms of such events, including the effect of temperature.

Abstract To reveal PM 1 vertical profiles and key affecting factors in a typical urban valley, daytime and nighttime PM 1 (the particles with diameters less than 1 μm) samples were collected with medium volume air samplers during 26 December 2017 to 11 January 2018 at five different altitudes by means of high topographic relief at urban areas of Lanzhou. The synchronous boundary layer temperature and humidity profiles were observed by a microwave radiometer. Daytime PM 1 concentrations reduced by about 3.86 μg m−3 when the height above the surface increased by 100 m, which was much lower than that for nighttime (5.68 μg m−3 100 m−1) as particles were easily accumulated near the surface when the air was stable during the nighttime. The three typical PM 1 vertical profiles were identified by K-means clustering technique. The most frequent cluster with elevated PM 1 concentrations near the surface was closely related to temperature inversion around the ground, while the cluster with relatively uniform PM 1 within the boundary layer was mainly induced by unstable atmospheric stratification and thus relatively good vertical dispersion. About 50%–60% of PM 1 variations could be attributed to atmospheric stratification near the surface in the valley city, which was much higher than that at the hilltop. The PM 1 difference increased by 47.14 (36.91) μg m−3 when inversion layer thickness (intensity) increased by 100 m (1 °C 100 m−1). The newly calculated inversion index considering both inversion layer thickness and intensity explained about 87% of PM 1 differences between near the surface and at the hilltop. The vertical dispersion had a more significant effect on PM 1 than horizontal dispersion near the surface, while PM 1 was more largely affected by horizontal dispersion at the hilltop, which was closely related to the valley terrain. Highlights • PM 1 vertical profiles were revealed in urban areas of Lanzhou for the first time. • Three typical PM 1 profile types were identified using K-means clustering technique. • PM 1 concentrations reduced by about 3–5 μg m−3 when the height increased by 100 m. • 50%–60% of PM 1 variations were attributed to atmospheric stratification near the surface. • PM 1 was more largely affected by vertical dispersion near the surface. [ABSTRACT FROM AUTHOR]

Highlights • Moisture recycling in different landscape area is assessed using stable isotope data. • Crop transpiration in oasis cannot be ignored, and its contribution to precipitation can reach 22%. • Mountain reservoirs increase the local water vapor recycling fraction. Abstract The hydrogen and oxygen isotope composition of precipitation and water vapor are useful tracers in the water cycle. The water balance of inland river basins located in the monsoon marginal zone are difficult to determine, because little is known about the contribution of various vapor involved. Based on the three-component isotopic mixing model, the monthly precipitation, surface water and plant water isotope data of the seven sampling stations from April to October 2017 were used to assess the vapor contribution to precipitation in the Shiyang River basin. The average contribution of plant transpiration, land surface evaporation and advected vapor to precipitation accounted for 11%, 6% and 83% in the Mountain regions, for 21%, 7% and 72% in the Oasis regions, and for 10%, 5% and 85% in the Desert regions, respectively. The contribution of plant transpiration and surface evaporation vapor was similar in time variation, and the maximum value appeared in July. The average plant transpiration vapor contribution at each station was always greater than the surface evaporation vapor. Different landscape and special underlying surfaces are important factors influencing the difference in water vapor contribution. The average surface evaporation water vapor contribution of the Xiying (M1) station is the largest in the study area, with a contribution fraction of 9%. The contribution of Wuwei oasis recycled moisture can reach 30%, the plant transpiration vapor accounted for 73%. [ABSTRACT FROM AUTHOR]

Aerosols affect the Earth's temperature and climate by altering the radiative properties of the atmosphere. Changes in the composition, morphological structure, and mixing state of aerosol components will cause significant changes in radiative forcing in the atmosphere. This work focused on the physicochemical properties of light-absorbing particles (LAPs) and their variability through deposition process from the atmosphere to the glacier–snowpack interface based on large-range observations in the northeastern Tibetan Plateau, and laboratory transmission electron microscope (TEM) and energy dispersive X-ray spectrometer (EDX) measurements. The results showed that LAP particle structures changed markedly in the snowpack compared to those in the atmosphere due to black carbon (BC) and organic matter (OM) particle aging and salt-coating condition changes. Considerably more aged BC and OM particles were observed in the glacier and snowpack surfaces than in the atmosphere, as the concentration of aged BC and OM varied in all locations by 4 %–16 % and 12 %–25 % in the atmosphere, whereas they varied by 25 %–36 % and 36 %–48 % in the glacier–snowpack surface. Similarly, the salt-coated particle ratio of LAPs in the snowpack is lower than in the atmosphere. Albedo change contribution in the Miaoergou, Yuzhufeng, and Qiyi glaciers is evaluated using the SNICAR model for glacier surface-distributed impurities. Due to the salt-coating state change, the snow albedo decreased by 16.7 %–33.9 % compared to that in the atmosphere. Such a great change may cause more strongly enhanced radiative heating than previously thought, suggesting that the warming effect from particle structure and mixing change in glacier–snowpack LAPs may have markedly affected the climate on a global scale in terms of direct forcing in the cryosphere. [ABSTRACT FROM AUTHOR]

Abstract: We present data of 129I deposition in fresh snow in the Laohugou glacier basin, northeast Tibetan Plateau, in summer 2016 and 2017, and trace its source and elevational distribution in the troposphere. Our results show that the 129I/127I atomic ratios in the fresh snow on the glacier surface are about 2 orders of magnitude larger than those in the Antarctic fresh snow and 4 orders the prenuclear level, indicating a predominantly anthropogenic source of the 129I in the mountain glacier environment of northeast Tibetan Plateau. The 129I level in the Laohugou glacier basin is 1–2 orders of magnitude lower than at representative European locations, and not significantly higher than that observed at other sites in Asia. The 129I/127I atomic ratio and 129I level show clear increases with elevation from 4,300 to 5,100 m above sea level. The 129I in the Laohugou glacier basin is probably deposited from the upper troposphere where there exists a local maximum of 129I. A conceptual model for interpretation of the observed 129I concentration and profile in Laohugou is provided. Thus, this work is of importance in providing a more complete view on the transport, dispersion, and removal of 129I in the atmosphere. [ABSTRACT FROM AUTHOR]

Estimation of evapotranspiration (ET) for alpine meadow areas in the Tibetan Plateau (TP) is essential for water resource management. However, observation data has been limited due to the extreme climates and complex terrain of this region. To address these issues, four representative methods, Penman-Monteith (PM), Priestley-Taylor (PT), Hargreaves-Samani (HS), and Mahringer (MG) methods, were adopted to estimate ET, which were then compared with ET measured using Eddy Covariance (EC) for five alpine meadow sites during the growing seasons from 2010 to 2014. And each site was measured for one growing season during this period. The results demonstrate that the PT method outperformed at all sites with a coefficient of determination (R2) ranging from 0.76 to 0.94 and root mean square error (RMSE) ranging from 0.41 to 0.62 mm d-1. The PM method showed better performance than HS and MG methods, and the HS method produced relatively acceptable results with higher R2 (0.46) and lower RMSE (0.89 mm d-1) compared to MG method with R2 of 0.16 and RMSE of 1.62 mm d-1, while MG underestimated ET at all alpine meadow sites. Therefore, the PT method, being the simpler approach and less data dependent, is recommended to estimate ET for alpine meadow areas in the Tibetan Plateau. The PM method produced reliable results when available data were sufficient, and the HS method proved to be a complementary method when variables were insufficient. On the contrary, the MG method always underestimated ET and is, thus, not suitable for alpine meadows. These results provide a basis for estimating ET on the Tibetan Plateau for annual data collection, analysis, and future studies. [ABSTRACT FROM AUTHOR]

To solve traffic congestion and to improve urban air quality, long-lasting and large-scale even-odd license plate controlled plan was implemented by local government during 20 November to 26 December 2016 in urban Lanzhou, a semi-arid valley city of northwest China. The traffic control measures provided an invaluable opportunity to evaluate its effects on urban air quality in less developed cities of northwest China. Based on measured simultaneously air pollutants and meteorological parameters, the abatement of traffic-related pollutants induced by the implemented control measures such as CO, PM 2.5 and PM 10 (the particulate matter with diameter less than 2.5 μm and 10 μm) concentrations were firstly quantified by comparing the air quality data in urban areas with those in rural areas (uncontrolled zones). The concentrations of CO, NO 2 from motor vehicles and fine particulate matter (PM 2.5 ) were shown to have significant decreases of 15%–23% during traffic control period from those measured before control period with hourly maximum CO, PM 2.5 , and NO 2 /SO 2 reduction of 43%, 35% and 141.4%, respectively. The influence of the control measures on AQI (air quality index) and ozone was less as compared to its effect on other air pollutants. Therefore, to alleviate serious winter haze pollution in China and to protect human health, the stringent long-term and large-scale even-odd license plate controlled plan should be implemented aperiodically in urban areas, especially for the periods with poor diffusion conditions. [ABSTRACT FROM AUTHOR]

An evaluation of glacial meltwater chemistry is needed under recent dramatic glacier melting when water resources might be significantly impacted. This study investigated trace elements variation in the meltwater stream, and its related aquatic environmental information, at the Laohugou (LHG) glacier basin (4260 m a.s.l.) at a remote location in northeast Tibetan Plateau. We focused on the spatial, temporal and diurnal change of trace elements during the glacier ablation period. Results showed evident elements spatial difference on the glacier surface meltwater, as most of the elements showed increased concentration at the terminus compared to higher elevations sites. Dominant elements in the meltwater were Ba, Sr and Cr, whereas elements with high enrichment factors (EFs) were Sb, Ni, Mo and Zn. Temporal change of some trace elements concentration (e.g. Sc, Cu, and Rb) indicated increasing trend with accelerated snow-ice melting, whereas others (e.g. Ni, Zn, and Pb) showed decreasing trend. We find that, trace elements showed evident diurnal change and a peak value of concentration was observed each day at about 15:00–17:00, and the diurnal change was influenced by runoff level and pH. Moreover, EFs calculations revealed that heavy metals were partially originated from regional anthropogenic sources. Overall, the accelerated diurnal and temporal snow-ice melting (with high runoff level) were correlated to increased elemental concentration, pH, EC and elemental change mode, and thus this work is of great importance for evaluating the impacts of accelerated glacier melting to meltwater chemistry and downstream ecosystem in the northeast Tibetan Plateau. [ABSTRACT FROM AUTHOR]

This paper reports a comprehensive study on the observed and projected spatiotemporal changes in mean and extreme climate over the arid region of northwestern China, based on gridded observation data and CMIP5 simulations under the RCP4.5 and RCP8.5 scenarios. The observational results reveal an increase in annual mean temperature since 1961, largely attributable to the increase in minimum temperature. The annual mean precipitation also exhibits a significant increasing tendency. The precipitation amount in the most recent decade was greater than in any preceding decade since 1961. Seasonally, the greatest increase in temperature and precipitation appears in winter and in summer, respectively. Widespread significant changes in temperature-related extremes are consistent with warming, with decreases in cold extremes and increases in warm extremes. The warming of the coldest night is greater than that of the warmest day, and changes in cold and warm nights are more evident than for cold and warm days. Extreme precipitation and wet days exhibit an increasing trend, and the maximum number of consecutive dry days shows a tendency toward shorter duration. Multi-model ensemble mean projections indicate an overall continual increase in temperature and precipitation during the 21st century. Decreases in cold extremes, increases in warm extremes, intensification of extreme precipitation, increases in wet days, and decreases in consecutive dry days, are expected under both emissions scenarios, with larger changes corresponding to stronger radiative forcing. [ABSTRACT FROM AUTHOR]

[Display omitted] [ABSTRACT FROM AUTHOR]

ABSTRACT We developed an annual tree-ring δ18O chronology from Larix sibirica in the eastern Tianshan Mountains of northwestern China. Climatic response revealed that tree-ring δ18O was significantly positively correlated with the mean and maximum July-August temperatures, whereas the July precipitation and relative humidity were significantly negatively correlated with tree-ring δ18O. The self-calibrating Palmer drought severity index (sc_PDSI) in July-August was significantly correlated with the tree-ring δ18O, which reflects the comprehensive effects of the three parameters on tree-ring δ18O fractionation. We established a robust reconstruction of July-August sc_ PDSI that accounted for 38.4% of the total variance of sc_PDSI from 1959 to 2008. The sc_PDSI reconstruction yields new insights on past drought that were not previously realized in other PDSI reconstructions (e.g. Monsoon Asia Drought Atlas) from the region. The reconstruction revealed several wet and dry periods but no trend towards a wetter climate in the eastern Tianshan Mountains during the last two decades. It also detected synergistic effects of the North Atlantic Oscillation and the El Niño-Southern Oscillation on regional moisture conditions as a result of teleconnections between tropical oceans and mid-latitude circulation patterns. [ABSTRACT FROM AUTHOR]

China's climate has been warming since the 1950s, with surface air temperature increasing at a rate higher than the global average. Changes in climate have exerted substantial impacts on water resources, agriculture, ecosystems and human health. Attributing past changes to causes provides a scientific foundation for national and international climate policies. Here, we review recent progress in attributing the observed climate changes over past decades in China. Anthropogenic forcings, dominated by greenhouse gas emissions, are the main drivers for observed increases in mean and extreme temperatures. Evidence of the effect of anthropogenic forcings on precipitation is emerging. Human influence has increased the probability of extreme heat events, and has likely changed the occurrence probabilities for some heavy precipitation events. The way a specific attribution question is posed and the conditions under which the question is addressed present persistent challenges for appropriately communicating attribution results to non-specialists. [ABSTRACT FROM AUTHOR]

Annual tree ring δO and δC chronologies from 1790 to 2008 were established using Tianshan spruce ( Picea schrenkiana) in the central Tianshan Mountains of northwestern China. Temperature has a positive effect on tree ring δO and δC in the study area, while precipitation and relative humidity have negative effects. The standardized precipitation-evapotranspiration index (SPEI) considered all of these effects and was significantly negatively correlated with tree ring δO and δC. We combined the tree ring δO and δC series to reconstruct the past 192 years of SPEI, which accounted for about 46 % of the total variance of SPEI from 1950 to 2006. The reconstruction showed good spatial agreement with gridded data in Palmer Drought Severity Index and precipitation and an inverse relationship with temperature. Our SPEI reconstruction reveals several wet and dry periods over the past 192 years and has good agreement with other drought records. Wavelet analysis showed quasi-periodic 10-, 20-, 30-, and 70-year fluctuations in the reconstruction. The 10-, 20-, and 30-year periodicities may reflect the potential influence of North Atlantic Oscillation (NAO). Overall, this study indicates that the SPEI is a potential drought index, and the winter NAO affects regional moisture conditions in the long term. [ABSTRACT FROM AUTHOR]

Relative humidity is an important factor in water and water vapor feedback cycles. In this study, we established a 222-year annual tree-ring δO chronology for Siberian larch ( Larix sibirica Ldb.) from the Altay Mountains in northwestern China. Climate response analyses revealed that the relative humidity was the primary factor limiting tree-ring δO fractionation. Based on our analysis, tree-ring δO can be used to reconstruct the July-August relative humidity based on both a reasonable mechanism of tree-ring δO fractionation and a statistically significant regression model. We used this model to reconstruct variations in the July-August relative humidity, and the model explained 47.4 % of the total variation in the measured relative humidity data from 1961 to 2011. The relative humidity in the study area increased from 1900 to the 1990s and decreased thereafter. Two regime-shift dry periods were detected during the study period (one from 1817 to 1830 and the other from 2004 to 2011). [ABSTRACT FROM AUTHOR]

Nitrate, an oxidized product of NO preserved in the polar ice cores, has often been used to estimate past changes of the atmospheric nitrogen cycle. A 102.65 m ice core drilled at DT-401 (79°01′S, 77°00′E) in 1999 provides an opportunity to investigate the possible influencing factors for the nitrate budget in the eastern Antarctica. We studied the relationship between the δO (representing the temperature), accumulation rate, volcanic deposition and the astronomical factors (such as the solar activities, supernovae, etc.), and the nitrate variation along the whole duration (2680-year) of the ice core. Prominent impacts of the accumulation rate acting on the nitrate flux rather than the concentration were detected. However, no significant correlation was found between the δO and the nitrate deposition characteristics (concentration and the flux variations). Volcanic deposition can significantly affect the deposition of nitrate with a decreasing trend accompanied by the nss-SO (volcanic signal) peak values. Impacts of the solar activities on the nitrate deposition can be detected at this site, and three prominent periodicities (16.6, 24.0 and 102.0 yr) were found for the nitrate concentration variations. Six climatic events (Dalton Minimum, Maunder Minimum, Sporer Minimum, Wolf Minimum, Oort Minimum and Medieval Maximum) during the past 1150 years were observed with lower nitrate values for the foregoing five events and higher value for the last one. [ABSTRACT FROM AUTHOR]

While Arctic sea ice has been decreasing in recent decades that is largely due to anthropogenic forcing, the extent of Antarctic sea ice showed a positive trend during 1979–2015, followed by an abrupt decrease. The shortness of the satellite record limits our ability to quantify the possible contribution of anthropogenic forcing and internal variability to the observed Antarctic sea ice variability. In this study, ice core and fast ice records with annual resolution from six sites are used to reconstruct the annual-resolved northernmost latitude of sea ice edge (NLSIE) for different sectors of the Southern Ocean, including the Weddell Sea (WS), Bellingshausen Sea (BS), Amundsen Sea (AS), Ross Sea (RS), and the Indian and western Pacific Ocean (IndWPac). The linear trends of the NLSIE are analyzed for each sector for the past 100–200 years and found to be −0.08°, −0.17°, +0.07°, +0.02°, and −0.03° per decade (≥95% confidence level) for the WS, BS, AS, RS, and IndWPac, respectively. For the entire Antarctic, our composite NLSIE shows a decreasing trend (−0.03° per decade, 99% confidence level) during the 20th century, with a rapid decline in the mid-1950s. It was not until the early 1980s that the observed increasing trend occurred. A comparison with major climate indices shows that the long-term linear trends in all five sectors are largely dominated by the changes in the Southern Annular Mode (SAM). The multi-decadal variability in WS, BS, and AS is dominated by the Interdecadal Pacific Oscillation, whereas that in the IndWPac and RS is dominated by the SAM. [ABSTRACT FROM AUTHOR]

Abstract: The central Himalaya can be regarded as an ideal site for developing a long-term ice core dust record to reflect the environmental signals from regional to semi-hemispheric scales. Here we present a dust record from segments of a 108.83-m ice core recovered from the East Rongbuk (ER) Glacier (27°59′N, 86°55′E; 6518 m a.s.l.) on the northeast slope of Mt. Qomolangma (Everest) in the central Himalaya, covering the period AD 600–1960. Due to rapidly layer thinning and coarse sampling, we primarily discuss the changes in the dust record since AD 1500 in this paper. Results show a significant positive relationship between the dust concentration and reconstructed air temperatures during this period, suggesting a likely cold–humid and warm–dry climatic pattern in the dust source regions, namely Central Asia. This is associated with the variability in the strength of the westerlies and its corresponding precipitation. [Copyright &y& Elsevier]

Annual accumulation records covering 1935 to 2004 were reconstructed using Geladaindong ice core in the source of Yangtze River. A significant positive correlation between annual accumulation and precipitation from nearby meteorological stations was found, suggesting ice core accumulation could be taken as a precipitation proxy in the region. In the past 70 years, precipitation in the Geladaindong region was low from 1930s to early 1960s, and the lowest value occurred in the later 1950s. Since 1960s, precipitation increased dramatically and reached the maximum around 1980s, then decreased slightly in 1990s. By using Mann-Kendall rank statistical test method, a change point for precipitation was determined in 1967. Analysis of the atmospheric circulation over the Tibetan Plateau suggested that, compared with the southwest wind during the low precipitation period (before 1967), it extended about 2 latitudes northward during high precipitation period (after 1967). Moreover, during the high precipitation, the trough over the Bal Karshi Lake was also enhanced, and both the meridional wind and vapor transporting displayed a remarkable aggrandizement. [ABSTRACT FROM AUTHOR]

Interests on climate change in the source region of Yangtze River have been raised since It Is a region with the greatest warming over the Tibetan Plateau (TP). A 70-year history of precipitation δ18O has been recovered using an Ice core record retrieved in a plat portion of the firn area In the Guoqu Glacier (33°34′37.8″N, 91°10′35.3″E, 5720 m a.s.l.), Mt. Geladaindong (the source region of Yangtze River), In November, 2005. By using a significant positive relationship between ice core δ18O record and summer air temperature (July to September) from the nearby meteorological stations, a history of summer air temperature has been reconstructed for the last 70 years. Summer temperature was relatively low in 1940s and high in 1950s to the middle of 1960s. The lowest temperature occurred In the middle of 1970s. Temperature was low in 1980s and dramatically increased since 1990s, keeping the trend to the beginning of the 21st century. The warming rate recorded in the ice core with 0.5°C/10 a since 1970s is much higher that that in the central TP and the Northern Hemisphere (NH), and it becomes 1.1°C/10 a since 1990s which is also higher than these from the central TP and the NH, reflecting an accelerated warming and a more sensitive response to global warming in the high elevation region. [ABSTRACT FROM AUTHOR]

This paper deals with the continuum modeling of traffic dynamics for freeways with two lanes where the faster vehicles are allowed to travel on both lanes while the slower vehicles are allowed to travel on one lane only. The speed gradient-based momentum equation is used to develop the traffic models for each lane. Using the proposed models, some nonequilibrium phenomena such as small disturbance instability and stop-and-go waves, together with results from numerical tests are investigated. The conditions for keeping the models' linear stability are presented. [ABSTRACT FROM AUTHOR]

During August and September 1998, fresh snow samples were collected in the East Rongbuk (ER) Glacier on the northern slope of Mt. Everest over an elevation range 5800–6500 m. Three snowpits were sampled in the ER glacier at an elevation of 6400, 6500, and 6500 m in August 1998, May 2000 and October 2002, respectively. Snow chemical data from fresh snow and snowpit samples from the ER Glacier are shown to be consistent with earlier results reported by other researchers from the vicinity of Mt. Everest. Among major ions, Ca2+ has the most striking seasonal differences: non-monsoon snow Ca2+ concentration is one order of magnitude higher than monsoon value. A large seasonal difference characterizes fresh snow SO42− but does not seem to persist in snowpit samples probably as a consequence of post-depositional ion elution. Non-monsoon snow Na+, K+ and Cl− are close to two times higher than monsoon snow for both fresh snow and snowpit samples. Magnesium has distinct seasonal variations in snowpit samples and a four-fold higher concentration in non-monsoon snow than that in monsoon snow. Seasonal differences in major chemical composition in snow over the Mt. Everest region provide a definitive indicator for precisely dating ice cores and as a consequence are essential in reconstructing the history of climate change and atmospheric chemistry in this region. [Copyright &y& Elsevier]

Investigates the accumulation and temperature changes in Princess Elizabeth Land, Antarctica. Trend of temperature and accumulation rate; Trend of climate change in the region.

The concentrations, optical and radiative effects of carbonaceous aerosols were essential to studies of the climatic, environmental and health effects. The previous studies less combined numerical simulation with in-situ observations, especially for the aerosol vertical profiles. In this study, we off-line measured vertical profiles of submicron black carbon (BC) aerosols and on-line obtained aerosol optical properties over urban Lanzhou during 26 December 2017 to 11 January 2018. The BC optical properties and radiative effects were evaluated using Optical Properties of Aerosols and Clouds (OPAC) and Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) models. The absorption and scattering coefficients and optical depth of BC aerosols ranged from 9 to 83 M m−1, 3–24 M m−1 and 0.02 to 0.2 respectively, which in average accounted for 50%, 3% and 11% of the optical properties of total aerosols during the study period. BC aerosol radiative forcing (ARF) within ATMOS (top-surface) varying from 16.6 to 108.8 W m−2 accounted for 17.3%–97.4% of total aerosols ARF with an average of 66.6%, and the percentages increased significantly as BC concentrations increased during the period. The mean atmospheric heating rate (AHR) induced by BC aerosols was 1.94 K day−1 ranging from 0.46 to 3.03 K day−1 during the study period. This study contributes to understanding the impacts of light-absorbing aerosols on climate and haze pollution in an urban valley. • BC optical properties were evaluated using OPAC model. • BC radiative forcing was evaluated using SBDART model. • Besides BC, other light-absorbing aerosols increased during high pollution episodes. • The mean heating rate induced by BC aerosols was 1.9 K day−1 over urban Lanzhou. [ABSTRACT FROM AUTHOR]

• The RMSE indicator flexible and intuitive express the trade-offs between multiple ESs. • Trade-offs varied greatly among the different ES pairs in mountain regions. • Large discrepancies exist in the mountain ESs along the elevation, VCF and precipitation. • The mechanisms underlying the changes of these trade-offs have been explored. Mountain ecosystems provide a variety of important ecosystem services (ESs) to humanity; however, the variation in multiple mountain ESs and the trade-off relationships among mountain ESs remain largely unknown. In this study, we took the Taihang Mountains as the study area and used the root mean square error (RMSE) method to quantify the trade-offs among multiple mountain ESs. Our results showed that net primary production (NPP), soil conservation (SC) and habitat quality (HQ) increased significantly with increasing elevation and vegetation cover fraction (VCF), whereas water yield (WY) did not. In addition, the trade-offs among different ES pairs had different sensitivities to changes in elevation, VCF and precipitation. As the elevation and VCF increased, the trade-offs between WY and NPP and WY and HQ increased significantly. As the precipitation increased, the trade-offs between SC and NPP, WY and NPP, HQ and SC, and WY and HQ all decreased significantly. In addition, the trade-offs among these four ESs were lowest in mid-elevation, high-VCF and low-mean annual precipitation (MAP) areas. This study could improve our current understanding of mountain ESs and help ES management for the Taihang Mountains. [ABSTRACT FROM AUTHOR]