Tibetan Plateau Region Research Articles

Combined effects of climate change on urban resilience in the Tibetan Plateau

Urban resilience refers to the ability of a city or region to adapt to changes and risks. However, the comprehensive impacts and mechanisms of adaptation and responses to climate change have not been sufficiently examined. Using the measured level of resilience of the Tibetan Plateau (TP) region from 1991 to 2020, the comprehensive static and dynamic effects of temperature and precipitation on urban resilience and the mechanisms thereof are discussed. The results are as follows: (1) The level of general urban resilience on the TP is rising in a fluctuating manner, and the regional differences are gradually increasing. (2) Temperature and precipitation factors play a significant role in increasing the level of resilience on the TP, and the degree of promotion shows regional heterogeneity. (3) Ecological resilience on the TP is most affected by temperature. Economic resilience is most affected by precipitation.

Genomic data provide a robust phylogeny backbone for Rhodiola L. (Crassulaceae) and reveal extensive reticulate evolution during its rapid radiation

The Tibetan Plateau and adjacent mountain regions (TP; including the Tibetan Plateau, Himalaya, Hengduan Mountains and Mountains of Central Asia) harbor great biodiversity, some lineages on which may have undergone rapid radiations. However, only a few studies have investigated the evolutionary pattern of such diversification in depth using genomic data. In this study, we reconstructed a robust phylogeny backbone of Rhodiola, a lineage that may have undergone rapid radiation in the TP, using Genotyping-by-sequencing data, and conducted a series of gene flow and diversification analyses. The concatenation and coalescent-based methods yield similar tree topologies, and five well-supported clades were revealed. Potential gene flow and introgression events were detected, both between species from different major clades and closely related species, suggesting pervasive hybridization and introgression. An initial rapid and later slowdown of the diversification rate was revealed, indicating niche filling. Molecular dating and correlation analyses showed that the uplift of TP and global cooling in the mid-Miocene might have played an important role in promoting the rapid radiation of Rhodiola. Our work demonstrates that gene flow and introgression might be an important contributor to rapid radiation possibly by quickly reassembling old genetic variation into new combinations.

Spatial influence of the Asian Summer Monsoon on pollen assemblages of the Tibetan Plateau and its potential implication for the interpretation of fossil pollen records

The direction and intensity of Asian Summer Monsoon (ASM) circulation in the Tibetan Plateau (TP) region strongly influence pollen dispersal patterns; however, this spatial effect has been rarely quantified. In this paper, we explore the relative importance of this directional spatial effect. Specifically, we construct a wind connectivity diagram for modern pollen sample sites according to the prevailing monsoon direction, and extract latent spatial variables representing the directional process of the ASM, using the method of asymmetric eigenvector maps. We fit redundancy analysis models using both spatial variables and local climate factors, and conduct variation partitioning to quantify the effect of directional spatial effect by the ASM. Taking into account the joint effect with local climate, the directional spatial process induced by the ASM significantly explains the variation of pollen assemblages on the TP. The effect is detected in pollen groups with contrasting functional types and dispersal modes; for example, the composition of arboreal pollen and non-arboreal pollen are both significantly affected by the ASM, yet best explained by models assuming different monsoon directions. Anemophilous pollen shows a higher percentage of variation explained by the ASM than non-anemophilous pollen. Our results indicate that directional processes induced by the monsoon is an important influence on pollen assemblages in the TP and support the idea that deposition patterns of pollen, especially arboreal pollen is a useful proxy for studying monsoon evolution. A similar approach can also be applied to paleomonsoon simulations using fossil pollen records. The role of directional dispersal in affecting fossil pollen composition and abundance by prevailing winds deserves further investigation when undertaking Quaternary paleoenvironmental reconstructions using pollen.

Aerosols heat up the Himalayan climate

The impact of aerosols, especially the absorbing aerosols, in the Himalayan region is important for climate. We closely examine ground-based high-quality observations of aerosol characteristics including radiative forcing from several locations in the Indo-Gangetic Plain (IGP), the Himalayan foothills and the Tibetan Plateau, relatively poorly studied regions with several sensitive ecosystems of global importance, as well as highly vulnerable large populations. This paper presents a state-of-the-art treatment of the warming that arises from these particles, using a combination of new measurements and modeling techniques. This is a first-time analysis of its kind, including ground-based observations, satellite data, and model simulations, which reveals that the aerosol radiative forcing efficiency (ARFE) in the atmosphere is clearly high over the IGP and the Himalayan foothills (80–135 Wm−2 per unit aerosol optical depth (AOD)), with values being greater at higher elevations. AOD is >0.30 and single scattering albedo (SSA) is ∼0.90 throughout the year over this region. The mean ARFE is 2–4 times higher here than over other polluted sites in South and East Asia, owing to higher AOD and aerosol absorption (i.e., lower SSA). Further, the observed annual mean aerosol-induced atmospheric heating rates (0.5–0.8 Kelvin/day), which are significantly higher than previously reported values for the region, imply that the aerosols alone could account for >50 % of the total warming (aerosols + greenhouse gases) of the lower atmosphere and surface over this region. We demonstrate that the current state-of-the-art models used in climate assessments significantly underestimate aerosol-induced heating, efficiency and warming over the Hindu Kush – Himalaya – Tibetan Plateau (HKHTP) region, indicating a need for a more realistic representation of aerosol properties, especially of black carbon and other aerosols. The significant, regionally coherent aerosol-induced warming that we observe in the high altitudes of the region, is a significant factor contributing to increasing air temperature, observed accelerated retreat of the glaciers, and changes in the hydrological cycle and precipitation patterns over this region. Thus, aerosols are heating up the Himalayan climate, and will remain a key factor driving climate change over the region.

Understanding land-use sustainability with a systematical framework: An evaluation case of China

Appraisals of land-use sustainability (LUS) are indispensable for the attainment of sustainable land-use planning and management. At present, China is experiencing a pivotal phase of comprehensive reform in land-use policy, engendering a practical necessity for system-oriented land evaluations. Despite this, studies focused on national-scale systematic LUS evaluation remain scarce. Within this context, we developed a hierarchical structural framework for land-use systems based on the assumption that sustainable land-use systems adapted to development needs have mutually adaptable internal subsystems and fewer conflicting system elements. Employing this framework, we assessed the LUS across Chinese counties from 2000 to 2015 by using a newly introduced static equilibrium equation；we also analyzed the natural and socioeconomic influences and driving effect of land-use change to LUS. Findings reveal a significant spatial clustering and urban-rural differentiation within the LUS spatial pattern. Five LUS hot and cold spots and eight metropolitan areas with poor LUS were identified. Furthermore, conflicting land capability elements and the non-adaptability of land function subsystems with capability subsystems are the primary constraints on LUS; gross domestic product (GDP), population growth, and the GDP growth per unit land area had the most significant impacts on LUS; The transformation of construction and cropland into ecological land and the re-purposing of grassland into building land are primary drivers of LUS. Our findings highlight the prospective utility of the proposed LUS framework in integrated natural resource management and territorial spatial planning. Meanwhile, Insights from this evaluation case could be harnessed to optimize land-use in critical regions (including northern arid and semiarid regions, the Qinghai–Tibet Plateau region, the poverty belt around the capital, Yangtze River Delta and Pearl River Delta metropolitan areas, as well as Fuzhou and Xiamen metropolitan areas), thereby enhancing land management decision-making processes.

The Radial Growth of Juniperus squamata Showed Sharp Increase in Response to Climate Warming on the Three-River Headwaters Region of Tibetan Plateau since the Early 21st Century

In order to explore the impact of climate change on the ecosystem at high altitudes, dendroclimatology was used to study the response of radial growth of Juniperus squamata Buch.-Ham. ex D.Don to the rapid warming in Nangqian County over the past 60 years, and a tree-ring width chronology for 115 years was established. (1) Meteorological data showed that the temperature in Nangqian County of the Tibetan Plateau has increased continuously during the past 60 years, and the minimum temperature has had the most significant change (0.63 °C/10a), especially between 2000–2019 (0.12 °C/a). Over the same time period precipitation has not changed significantly (0.94 mm/a, p > 0.10). The standard chronology was used to reconstruct the mean temperature series from July to September in Nangqian meteorological station during the past 115 years (1905–2019). The explained variance of the reconstructed equation was 42.8% (40.8%, after adjusting for degrees of freedom). The reconstructed temperature series can be roughly divided into two stages: from 1905 to 1999, the temperature fluctuated around the average value, 12.10 °C, and from 2000 to 2019, the temperature showed a significant upward trend. (2) The analysis of the climate-tree growth relationship indicated that the response of radial growth of Juniperus squamata to temperature was significantly stronger than the response to precipitation; especially in the last 20 years, when the radial growth of Juniperus squamata was positively correlated with temperature (p < 0.01). Compared to the maximum temperature and mean temperature, the correlation between radial growth of Juniperus squamata and minimum temperature was more significant. (3) Under the background of climate warming, the radial growth trend of Juniperus squamata in Nangqian county was consistent with temperature changes. Particularly in the past 20 years, the radial growth of Juniperus squamata showed a significantly increased trend and entered a rapid growth period.

Late Holocene vegetation and climate change in the northern Tibetan Plateau region based on a palynological analysis from Lake Ayakum

In this paper, we undertake a high-resolution palynological analysis of a sediment core covering the last 1500 years obtained from Lake Ayakum in the northern Tibetan Plateau, to improve the understanding of regional climate fluctuations and their driving mechanisms. The pollen spectra are dominated by herbaceous species such as Artemisia, Chenopodiaceae, Cyperaceae and Poaceae, which grew in various alpine desert settings. Four pollen assemblage zones are identified using stratigraphically constrained cluster analysis, representing climate history at different stages. The Artemisia/Chenopodiaceae (A/C) ratio and axis score of the first principal component are used to infer regional moisture conditions and reveal a temporal pattern that is consistent with various records from central Asia. The source of Cyperaceae pollen is mainly from marsh wetlands distributed around the lake, which responded sensitively to the lake level fluctuations. In contrast, arboreal pollen is mainly a long-distance transported component, reflecting changes in regional vegetation. Our findings show that the northern Tibetan Plateau experienced relatively wet conditions during the Dark Age Cold Period and the Little Ice Age, while relatively dry conditions occurred during the Medieval Warm Period and the last two centuries. Fluctuations in moisture levels are broadly consistent with moisture records elsewhere in western China, and show a good correlation with phase changes of the North Atlantic Oscillation. The climate changes in the northern Tibetan Plateau are supposed to be primarily triggered by the NAO phases through south-north migrations of the mid-latitude westerlies during the late Holocene.

Understanding indigenous people's traditional Chinese medicinal plants harvesting preferences to guide sustainable management

Abstract Surging demand for medicinal plant products may lead to unsustainable harvesting practices, which could put pressure on wild populations. Yet little is known about indigenous harvesters' preferences on key traditional Chinese medicinal plant resources, and how these might affect sustainable use and management. We conducted a discrete choice experiment with over 900 native Tibetan harvesters in the eastern Qinghai–Tibetan plateau in China, under a range of complex alternative livelihood, climate and environmental change, and land tenure and customs scenarios. We used random parameter logit model with broad heterogeneity to estimate local Tibetan harvesters' preferences and their willingness to harvest, and latent class logit model to explore distinct within‐population groupings based on shared preferences, for designing possible interventions. We uncovered three key findings with important management implications for medicinal plants. When given a choice, the local harvesters preferred not to harvest any herbs. However, if they opted to harvest, they preferred to harvest flowers and seeds, as compared to roots, and tended to use wooden tool (over the use of bare hands and iron tool). Notably, the degree of compliance with village rules and customs, and ecological worldview interact with targeted plant parts and potential income from harvest to influence their harvesting preferences. Their choices were sensitive to scenario‐based changes to livelihood options. Finally, our study revealed three distinct harvester groups with substantial heterogeneity. Specifically, two groups consisted of over 60% of the interviewed harvesters who appeared to have a strong preference for sustainable practices, while the remaining group lacks this tendency. Overall, our results shed light on the importance of understanding the drivers of harvesting preferences and the heterogeneity of harvesting practices among indigenous people and their cultural and sustainability leanings, providing crucial insights for future sustainable use and management of wild and economically important medicinal plants in the grasslands of Qinghai–Tibetan Plateau and other regions. Read the free Plain Language Summary for this article on the Journal blog.

The Forecast Skill of the Summer Precipitation Over Tibetan Plateau Improved by the Adoption of a 3D Sub‐Grid Terrain Solar Radiative Effect Scheme in a Convection‐Permitting Model

AbstractWe have successfully incorporated a 3‐dimensional sub‐grid terrain solar radiative effect (3D STSRE) parameterization scheme into a convection‐permitting Weather Research and Forecasting model (WRF_CPM) in this study. Impacts of 3D STSRE scheme on the ability of WRF_CPM in forecasting the precipitation in summer over the Tibetan Plateau (TP) and nearby regions with complex terrain have been systematically addressed by conducting experiments without and with the 3D STSRE scheme. Results show that the application of 3D STSRE scheme can obviously mitigate the overestimation of surface solar radiation (SSR) and rainfall over TP and nearby regions, especially over the areas with much more rugged terrain (i.e., southern TP) in the WRF_CPM without 3D STSRE scheme. Further mechanism analyses indicate that the decreased surface heating induced by the reduction of SSR reduces the intensity of the thermal‐low pressure over the TP, which leads to the diminished strength of southwesterly winds and thereafter the weaker convergence of moisture flux over the southern TP. Moreover, the weakened surface thermal forcing makes the local atmosphere more stable, suppressing the vertical water vapor transport and local convection. These effects greatly alleviate the overestimation of precipitation over the southern TP produced by the WRF_CPM without the 3D STSRE scheme.

Southern Himalayas rainfall as a key driver of interannual variation of pre-monsoon aerosols over the Tibetan Plateau

The Tibetan Plateau (TP) is one of the most climate-sensitive regions around the world. Aerosols imported from adjacent regions reach their peak during the pre-monsoon season and play a vital role in the TP environment. However, the strong interannual variation in aerosols transported to the TP has not been fully understood. Here, we show that the interannual variability of pre-monsoon aerosols transported to the TP is influenced more by rainfall over the southern Himalayas than near-surface wind. Rainfall modulates fire events and biomass burning emissions and reduces aerosols over the TP by wet scavenging. Contrary to the role of wind in increasing aerosol transport, the positive correlation between wind and aerosols in the TP reported in previous studies is contributed by the negative interannual correlations between wind and rainfall and between rainfall and fire events over the southern Himalayas. This study highlights the co-variability of wind and rainfall and their confounding impacts on aerosols in the southern Himalayas and over the TP. With pre-monsoon rainfall projected to increase in adjacent regions of southern TP, aerosol transport to the TP may be mitigated in the future.

Epidemiological characteristics and risk factors for cystic and alveolar echinococcosis in China: an analysis of a national population-based field survey

BackgroundHuman cystic and alveolar echinococcosis are neglected tropical diseases that WHO has prioritized for control in recent years. Both diseases impose substantial burdens on public health and the socio-economy in China. In this study, which is based on the national echinococcosis survey from 2012 to 2016, we aim to describe the spatial prevalence and demographic characteristics of cystic and alveolar echinococcosis infections in humans and assess the impact of environmental, biological and social factors on both types of the disease.MethodsWe computed the sex-, age group-, occupation- and education level-specific prevalences of cystic and alveolar echinococcosis at national and sub-national levels. We mapped the geographical distribution of echinococcosis prevalence at the province, city and county levels. Finally, by analyzing the county-level echinococcosis cases combined with a range of associated environmental, biological and social factors, we identified and quantified the potential risk factors for echinococcosis using a generalized linear model.ResultsA total of 1,150,723 residents were selected and included in the national echinococcosis survey between 2012 and 2016, of whom 4161 and 1055 tested positive for cystic and alveolar echinococcosis, respectively. Female gender, older age, occupation at herdsman, occupation as religious worker and illiteracy were identified as risk factors for both types of echinococcosis. The prevalence of echinococcosis was found to vary geographically, with areas of high endemicity observed in the Tibetan Plateau region. Cystic echinococcosis prevalence was positively correlated with cattle density, cattle prevalence, dog density, dog prevalence, number of livestock slaughtered, elevation and grass area, and negatively associated with temperature and gross domestic product (GDP). Alveolar echinococcosis prevalence was positively correlated with precipitation, level of awareness, elevation, rodent density and rodent prevalence, and negatively correlated with forest area, temperature and GDP. Our results also implied that drinking water sources are significantly associated with both diseases.ConclusionsThe results of this study provide a comprehensive understanding of geographical patterns, demographic characteristics and risk factors of cystic and alveolar echinococcosis in China. This important information will contribute towards developing targeted prevention measures and controlling diseases from the public health perspective.Graphical

Precipitation Conditions Constrain the Sensitivity of Aboveground Net Primary Productivity in Tibetan Plateau Grasslands to Climate Change

Continued climate warming and precipitation fluctuations are expected to further affect aboveground net primary productivity (ANPP) across alpine grasslands, with associated implications for ecosystem functions. The spatial and temporal variability of ANPP in Tibetan Plateau (TP) grasslands and its response to temperature and precipitation were investigated in this study, based on the ANPP estimated by means of ensemble analysis of multiple machine learning models. First, the response of the spatial distribution of ANPP to variations in the precipitation gradient was nonlinear and showed an S-shaped growth pattern, which could be divided into four stages (stationary, rapid growth, slower growth, and saturation) corresponding to arid (mean annual precipitation (MAP) < 250 mm), semiarid (250 mm < MAP < 450 mm), semihumid (450 mm < MAP < 650 mm) and humid (MAP > 650 mm) precipitation regimes, respectively. Second, regional precipitation regimes affected the sensitivity of ANPP’s interannual variability to temperature and precipitation; ANPP is more sensitive to temperature in wetter areas than in dryer areas of the TP region. The results of our study suggest that in the region of Tibetan Plateau, the response of grassland ANPP variation to climate was constrained by the background precipitation regimes.

Climate and vegetation codetermine the increased carbon burial rates in Tibetan Plateau lakes during the Holocene

The Tibetan Plateau (TP), also known as the “Asian Water Tower,” includes thousands of lakes containing sizable lacustrine sediments that have been proven to be important carbon pools of inland ecosystems. To develop an in-depth understanding of the status of TP lake carbon storage and its response to global changes and human activities, we accurately quantified the change trend of long-term organic carbon burial in lakes over the TP, compared levels of differentiation within the TP, and explored related driving factors of the carbon accumulation rates (CARs) by compiling 24 lake sediment cores. The results show that the lake CAR over the TP presented a rising trend during the Holocene, with an average of 6.50 g C m−2 yr−1 and levels ranging from 1.75 to 18.41 g C m−2 yr−1. The eastern TP (ETP), with warmer and wetter climate conditions and more vegetation coverage, had almost twice the CAR as that of the central and western TP (CWTP). We demonstrate that climate and vegetation could be the main drivers of the lake CAR on the TP despite environmental heterogeneity contributing to subregional discrepancies. During the early Holocene, superior summer temperatures and precipitation favored vegetation development, providing abundant material for lake carbon deposition. In the middle Holocene, together with vigorous vegetation, decreasing summer temperatures led to a decline in mineralization, which enhanced carbon storage efficiency and resulted in an increase in the CAR across the ETP. In contrast, for the CWTP, herbaceous-dominated vegetation continued to expand during the early-mid Holocene, which constrained detritus supply, thus maintaining a relatively stable CAR. However, intensive human activities could be responsible for the CAR peak in the late Holocene on the TP, especially since 2000 cal yr BP. In addition to the anthropogenic impacts, variations in CAR among lakes resulting from local factors lead to large uncertainties in future C predictions for the whole region of TP.

Storage periods and heating terminals types influence on the solar heating thermal storage volume in the Tibetan Plateau regions

The scale of the thermal storage system is critical to balancing system fluctuations caused by the mismatch between solar heat collection and heating load in time and space for solar heating systems. This study investigates the relationship between solar collector area and heat storage volume under the different storage periods and heating terminals types. This research simulates the heat storage volumes using a typical day, continuous overcast days, and heating period as thermal storage periods, based on solar radiation intensity, building heating load, and cloudy days in seven typical Tibetan regions. According to the results, the storage volume per unit collector area Vs/Ac increases with increasing temperature difference and storage period in the Tibetan Plateau. It is proposed that Lhoka, Chamdo, Nagqu, Lhasa, Shigatse, and Nyingchi take continuous overcast and cloudy days as thermal storage periods, and Ngari uses the heating period as thermal storage periods, corresponding to the Vs/Ac ranges of 0.27 m3/m2–0.9 m3/m2 and 1.6 m3/m2–1.8 m3/m2. Specifically, preheating the heat storage tank can improve the solar fraction fsim by 2.5 %, with the recommended preheating temperature of 50 °C. In addition, the variation equation for design solar fraction fn and Vs/Ac was obtained. These results can be utilized to develop solar heating systems on the Tibetan plateau.

Microplate boundaries and patterns in the southern Tibetan Plateau revealed by gravity and magnetic data

The Tibetan Plateau is located in the eastern part of the Tethys-Himalayan megatectonic domain and consists of a series of microplates that successively accreted to the southern edge of the Eurasian Continent. These microplates have undergone complex evolutionary processes during rifting, drift and collision. The gravity and magnetic anomalies show that the anomaly characteristics on the Tibetan Plateau is significantly different in the north-south direction, from the Qaidam Microplate to the Lhasa Microplate. In this paper, we apply an improved Logistic Filter method, combined with the upward continuation of gravity anomalies, to identify multi-scale tectonic boundaries in the Tibetan Plateau region. The results show that the edge detection results correspond well in space with fracture zones and suture/ophiolite zones. Also, there are clear discontinuities along both sides of the middle and western sections of the Bangong-Nujiang Suture Zone and the eastern section of the Jinshajiang-Ailaoshan Suture Zone. We refined the boundaries of five microplates, including the South and North Qiangtang and the South, Central and North Lhasa, in the southern Tibetan Plateau. Then, we analyzed the evolutionary processes of these microplates and the transformation of the types to which the microplates belonged during different historical periods by combining relevant evidences from other geological records and plate reconstruction. These microplates are strongly related to the evolutionary history of the Tethys Ocean. The closure of the Neo-Tethys Ocean triggered a large-scale orogeny between the Indo-Asian continents, and these microplates were eventually accreted in the orogenic belt. We analyze the formation patterns and boundary types of microplates in the evolutionary process and then divide into three stages, i.e., rifting-derived, accretion-derived, and subduction-derived stages. The transformation patterns of microplate types at different stages provide a new perspective for the study of the evolution of mega-orogenic belts.

An Innovative Approach for Effective Removal of Thin Clouds in Optical Images Using Convolutional Matting Model

Clouds are the major source of clutter in optical remote sensing (RS) images. Approximately 60% of the Earth’s surface is covered by clouds, with the equatorial and Tibetan Plateau regions being the most affected. Although the implementation of techniques for cloud removal can significantly improve the efficiency of remote sensing imagery, its use is severely restricted due to the poor timeliness of time-series cloud removal techniques and the distortion-prone nature of single-frame cloud removal techniques. To thoroughly remove thin clouds from remote sensing imagery, we propose the Saliency Cloud Matting Convolutional Neural Network (SCM-CNN) from an image fusion perspective. This network can automatically balance multiple loss functions, extract the cloud opacity and cloud top reflectance intensity from cloudy remote sensing images, and recover ground surface information under thin cloud cover through inverse operations. The SCM-CNN was trained on simulated samples and validated on both simulated samples and Sentinel-2 images, achieving average peak signal-to-noise ratios (PSNRs) of 30.04 and 25.32, respectively. Comparative studies demonstrate that the SCM-CNN model is more effective in performing cloud removal on individual remote sensing images, is robust, and can recover ground surface information under thin cloud cover without compromising the original image. The method proposed in this article can be widely promoted in regions with year-round cloud cover, providing data support for geological hazard, vegetation, and frozen area studies, among others.

Pulsed counterclockwise rotation of the southwestern Sichuan Basin in response to the India-Asia convergence during 128-42 Ma

Deciphering the building history of the eastern Tibetan Plateau since the India-Asia convergence is crucial to understand geodynamic models of plateau formation. The Sichuan Basin adjacent to the eastern Tibetan Plateau margin potentially provides valuable records of when and how the Tibetan Plateau expanded eastward. In this study, we reconstruct ∼128–42 Ma rotation history of the southwestern Sichuan Basin using detailed paleomagnetic declination data from the Early Cretaceous to Eocene sedimentary sequence of ∼2400 m thick. A total of 78 sampling sites (774 samples) yield primary remanent magnetization confirmed by positive paleomagnetic tests. Our results show that the southwestern Sichuan Basin experienced a long-term clockwise rotation during 128–42 Ma which was interrupted by three transient and rapid counterclockwise rotation pulses. The earlier two pulses (86–82 Ma and 66–60 Ma) coincide with two India Plate acceleration episodes which are probably induced by the Marion and/or Réunion mantle plume upwelling, whereas the later pulse (53–46 Ma) temporally corresponds to the sudden slowdown of the India Plate caused by the India-Asia collision. Our findings indicate that the eastern Tibetan Plateau experienced prolonged and episodic building processes since the Late Cretaceous, long predating the traditional view of the late Miocene. The Tibetan Plateau was built synchronously from the Himalayas to its eastern margin. Lateral extrusion, block rotation, and strike-slip deformation collectively contribute to the mountain building in the eastern Tibetan Plateau region.

Assessment of Conservation Effectiveness of the Qinghai–Tibet Plateau Nature Reserves from a Human Footprint Perspective with Global Lessons

The intensity of human pressure (HP) has an important impact on the biodiversity and ecosystem services of nature reserves (NRs), and the conflict and the coordination between NRs and human activities are now key issues to solve in the construction of NR systems. This study improved and applied a human footprint (HF) model that considers population density, land use, night light, grazing intensity, and road construction as indicators of human activity to evaluate the effectiveness of NRs in the Qinghai–Tibet Plateau in mitigating HP from 2000 to 2020. The results indicated that during this period, the average HP in the national NRs of the plateau increased from 1.47646 to 1.76687, where values were generally high in the east and low in the west. The average value in wetland NRs was the largest and had the smallest growth rate, while that in desert NRs was the smallest and had the largest growth rate. From 2000 to 2020, the average HP in the core areas, buffer areas, and experimental areas of the NRs increased by 0.12969, 0.29909, and 0.44244, respectively. It is a challenge for the Chinese government to strengthen the ability of NRs to mitigate HP on the wetland reserves and experimental zones in the Qinghai–Tibet Plateau region.

Applications of CNOP-P Method to Predictability Studies of Terrestrial Ecosystems

In this paper, recent research on terrestrial ecosystem predictability using the conditional nonlinear optimal parameter perturbation (CNOP-P) method is summarized. The main findings include the impacts of uncertainties in climate change on uncertainties in simulated terrestrial ecosystems, the identification of key physical parameters that lead to large uncertainties in terrestrial ecosystem modeling and prediction, and the evaluation of the simulation ability and prediction skill of terrestrial ecosystems by reducing key physical parameter errors. The study areas included the Inner Mongolia region, north–south transect of eastern China, and Qinghai–Tibet Plateau region. The periods of the studies were from 1961 to 1970 for the impacts of uncertainties in climate change on uncertainties in simulated terrestrial ecosystems, and from 1951 to 2000 for the identification of the most sensitive combinations of physical parameters. Climatic Research Unit (CRU) data were employed. The numerical results indicate the important role of nonlinear changes in climate variability due to the occurrences of extreme events characterized by CNOP-P in the abrupt grassland ecosystem equilibrium state and formation of carbon sinks in China. Second, the most sensitive combinations of physical parameters to the uncertainties in simulations and predictions of terrestrial ecosystems identified by the CNOP-P method were more sensitive than those obtained by traditional methods (e.g., one-at-a-time (OAT) and stochastic methods). Furthermore, the improvement extent of the simulation ability and prediction skill of terrestrial ecosystems by reducing the errors of the sensitive physical parameter combinations identified by the CNOP-P method was higher than that by the traditional methods.

Impact of climate change on the long-term water balance in the Yarlung Zangbo basin

The Himalayan and Tibetan Plateau (TP) region serves as the “Asian water tower”. Yarlung Zangbo basin (YZB) is one of most important major rivers originating from TP sustaining billions of lives in the downstream alluvial plain. Climate change has impacted the hydrological cycle in this alpine region; however, the temporal and spatial trends of runoff and the water balance has not been quantified adequately. Here, we have optimized the snowmelt module of the Soil and Water Assessment Tool (SWAT) for the YZB to quantify the historical and future variability in the runoff, snowmelt water, and water balance components. According to the results of the Coupled Model Intercomparison Project Five and Six (CMIP5 and CMIP6) the future precipitation (2020–2099) projected by the CMIP6 will increase by 2.7% when compared to historical reference (1980–2019), while the precipitation will increase by 10.2% when projected by the CMIP5. The increase in average air temperature (2.4°C) projected by CMIP6 exceeds that of CMIP5 (1.9°C). The runoff between 2020 and 2050 will decrease by −12.7% compared with historical reference, and it will further decline by −9.2% during 2060 and 2099. Based on the average results of CMIP5 and CMIP6, the water balance deficit will increase primarily due to an increase in evaporation of 42.4%, whereas snowmelt (−32.1%), water yield (−9.4%), soil water (−19.8%), and groundwater recharge (−17.8%) will decrease. Long-term water balance evaluation implicates that middle and upper reaches will face a higher risk of drought, implying a potential threat to the sustainability of grassland ecosystems upstream.