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Pollen-based Holocene quantitative temperature reconstruction on the eastern Tibetan Plateau using a comprehensive method framework

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Science China Earth Sciences 2020年第8期63卷 1144-1160页

作者： Chen LIANG Yan ZHAO Feng QIN Zhuo ZHENG Xiayun XIAO Chunmei MA Huan LI Wenwei ZHAO Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Department of Earth Science Sun Yat-sen UniversityGuangzhou 510275China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography&LimnologyChinese Academy of SciencesNanjing 210008China School of Geography and Ocean Science Nanjing UniversityNanjing 210023China Department of Earth Sciences Vrije Universiteit AmsterdamAmsterdam 1081 HVThe Netherlands School of Geographic Science Nantong UniversityNantong 226009China

Quantitative climate reconstruction on long timescales can provide important insights for understanding the climate variability and providing valuable data for simulations. Unfortunately, the credibility of some attempts was hampered by incomplete reconstruction procedures. We here establish a comprehensive framework resting on high-quality Chinese modern pollen database, including modern pollen data screening, calibration set selection, major climate factor analysis, appropriate model selection, strict statistical assessment of results and ecological interpretation. The application of this framework to three high-resolution pollen records from the eastern Tibetan Plateau allows accurate quantitative inferences of Holocene temperature changes, which is the major control of regional vegetation. The results show that the mean warmest month temperature(MTwa)during the early Holocene was ca. 10.4℃ and reached the highest value at 8.5–6 ka BP(ca. 11℃). The early and mid-Holocene(11–5 ka BP) warmth was followed by 1.2℃ temperature decrease, culminating in the coolest temperatures of the Holocene during the Neoglacial cooling. Superimposing on the general cooling trend, MTwareveals a significant 500-yr periodicity with varying intensities through time, showing that warm(cold) intervals are in phase with solar maxima(minima) periods. This spectral similarity indicates a possible connection of multi-century scale climate fluctuations with solar forcing.

关键词： Approach framework of quantitative reconstruction Tibetan Plateau Holocene Temperature changes Periodicity

Spatial variability and long-term change in pollen diversity in Nam Co catchment(central Tibetan Plateau): Implications for alpine vegetation restoration from a paleoecological perspective

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Science China Earth Sciences 2018年第3期61卷 270-284页

作者： LI Quan Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Pollen diversity offers abundant clues into the floristic diversity and history of vegetation change. Few palynological studies investigated modem pollen diversity or the past floristic diversity on the Tibetan Plateau （TP）. Based on modem pollen assemblages from 37 topsoils and 63 surface lake sediments in the Nam Co catchment on the central TP, this study quantitatively explored spatial distribution of modem pollen diversity using Shannon-Wiener index （H） and palynological richness （E（Tn）, n=600）. Pollen diversity indices showed spatial variability among vegetation types, reflecting the differences in terrestrial floristic diversity in the lake catchment. Their values were high in the southeastern region of the lake catchment which is covered by alpine steppe, while values were low for alpine meadow and marsh meadow. The pollen diversity in lacustrine pollen assemblage could be an effective proxy to document past floristic diversity. The past floristic diversity in the lake catchment, recovered from a fossil pollen record ofNMLC-1, showed a long-term change of ascending overlaid by several rapid diversity changes during the last 8400 years due to the downward shift of altitudinal vegetation belt driven by a general climatic cooling. The results imply that under the environmental challenge of climate warming and vegetation degradation, alpine vegetation restoration in the Nam Co catchment and the central TP should pay attention to altitudinal vegetation belt and zonal vegetation of alpine steppe, and use the long-term change of floristic diversity as a historical analogue.

关键词： Pollen diversity Palynological richness Vegetation restoration Nam Co Lake Tibetan Plateau

Global Future Population Exposure to Heatwaves

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SSRN 2023年

作者： Wang, Yuwei Zhao, Na Yin, Xiaozhe Wu, Chaoyang Chen, Mingxing Jiao, Yimeng Yue, Tianxiang State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100101 China Jiangsu Center for Collaborative Innovation in Geographic Information Resource Development and Application Nanjing210023 China Department of Environmental Health Harvard T.H. Chan School of Public Health BostonMA United States Key Laboratory of Land Surface Pattern and Simulation Institute Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China

The increasing exposure to extreme heatwaves in urban areas from both climate change and the urban heat island (UHI) effect is posing multiple threats and challenges to human society. Despite a growing number of studies focusing on extreme exposure, research advances are still limited in some aspects like oversimplifies of some inter-individual factors of human exposure, resulting in unreliable and unrealistic estimates of future results. In addition, little research performed comprehensive and fine-resolution global analysis in future scenarios. In this study, we present the first global fine-resolution projection of future changing urban population exposure to heatwaves by 2100 under four shared socioeconomic pathways (SSPs) by considering the urban development at global, regional, and national scales. Overall, global urban population exposure to heatwaves is rising under the four SSPs. Temperate and tropical zones predictably have the greatest exposure among all climate zones. Coastal cities are projected to have the greatest exposure, followed closely by cities at low altitudes. Middle-income countries have the lowest exposure and the lowest inequality of exposure among countries. Individual climate effects contributed the most (about 46.4%) to future changes in exposure, followed by the interactive effect between climate and urbanization (about 18.5%). Our results indicate that more attention needs to be paid to policy improvements and sustainable development planning of global coastal cities and some low-altitude cities, especially in low- and high-income countries. Meanwhile, this study also highlights the impact of continued future urban expansion on population exposure to heatwaves. © 2023, The Authors. All rights reserved.

关键词： Climate change

Climatic and Biotic Controls of Evapotranspiration Across Grassland Ecosystems on Tibetan Plateau

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SSRN 2024年

作者： Peng, Siyuan Yang, Yue Luo, Dengnan Zeng, Xiang Liang, Minqi Tao, Long Zhang, Guangru Li, Pan Liao, Weijie Guo, Qun Cao, Ruochen Li, Yuzhe Zhang, Weirong Hu, Zhongmin School of Geography South China Normal University Shipai Campus Guangzhou510631 China Hainan Baoting Tropical Rainforest Ecosystem Observation and Research Station School of Ecology Hainan University Haikou570228 China Facility of Geographical Science Beijing Normal University Beijing100875 China Zhuhai Branch State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Zhuhai519087 China School of Atmospheric Sciences Guangdong Province Data Center of Terrestrial and Marine Ecosystems Carbon Cycle Sun Yat-sen University Guangdong Zhuhai510245 China Key Lab of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing101408 China International Institute for Earth System Sciences Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing University Jiangsu 210023 China Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Key Laboratory for Land Satellite Remote Sensing Applications Ministry of Natural Resources School of Geography and Ocean Science Nanjing University Jiangsu 210023 China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Comprehending the spatial variations of evapotranspiration (ET) and its components on Tibetan Plateau (TP) is crucial for grasping the dynamics of the regional water cycle and energy balance. However, the influence of various environmental factors on ET and its components remains unclear. This study addresses this gap by utilizing observational data from 14 sites and employing the Shuttleworth-Wallace-Hu (SWH) model to examine the spatial relationships between ET, its components, and influencing factors. The SWH model parameters were optimized using the Monte Carlo method, achieving a satisfactory simulation performance with an average R2 value of 0.75. Our analysis indicates that in alpine meadow, the ratio of transpiration to ET is generally higher (0.55) compared to alpine steppe (0.39). In terms of spatial distribution, both precipitation and leaf area index significantly impact ET and transpiration. Precipitation emerges as the primary driver of interannual spatial variations in ET, while leaf area index plays a pivotal role in regulating proportion of transpiration. Furthermore, our results reveal a transition from water-dominated to energy-dominated in TP grassland ecosystem at an aridity index of 0.73. This finding is significant as it challenges the common application of an aridity index of 0.65 to distinguish arid from humid regions. It suggests that TP grassland, within the 0.65-0.73 range, remain primarily water-driven. These findings enhance our comprehension of the intricate interactions within the water cycle. © 2024, The Authors. All rights reserved.

关键词： Evapotranspiration

Sensitivity of arid/humid patterns in China to future climate change under a high-emissions scenario

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Journal of Geographical Sciences 2019年第1期29卷 29-48页

作者： MA Danyang DENG Haoyu YIN Yunhe WU Shaohong ZHENG Du Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research CAS University of Chinese Academy of Sciences Henan Province Development and Reform Commission

Changes in regional moisture patterns under the impact of climate change are an important focus for science. Based on the five global climate models (GCMs) participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5), this paper projects trends in the area of arid/humid climate regions of China over the next 100 years. It also identifies the regions of arid/humid patterns change and analyzes their temperature sensitivity of responses. Results show that future change will be characterized by a significant contraction in the humid region and an expansion of arid/humid transition zones. In particular, the sub-humid region will expand by 28.69% in the long term (2070-2099) relative to the baseline period (1981-2010). Under 2°C and 4°C warming, the area of the arid/humid transition zones is projected to increase from 10.17% to 13.72% of the total of China. The humid region south of the Huaihe River Basin, which is affected mainly by a future increase in evapotranspiration, will retreat southward and change to a sub-humid region. In general, the sensitivity of responses of arid/humid patterns to climate change in China will intensify with accelerating global warming.

关键词： arid/humid patterns climate change sensitivity aridity index China

Climatic and Biotic Controls of Evapotranspiration Across Grassland Ecosystems on the Tibetan Plateau

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SSRN 2024年

作者： Peng, Siyuan Yang, Yue Luo, Dengnan Zeng, Xiang Liang, Minqi Tao, Long Zhang, Guangru Li, Pan Liao, Weijie Guo, Qun Cao, Ruochen Li, Yuzhe Zhang, Weirong Hu, Zhongmin School of Geography South China Normal University Shipai Campus Guangzhou510631 China Hainan Baoting Tropical Rainforest Ecosystem Observation and Research Station School of Ecology Hainan University Haikou570228 China Facility of Geographical Science Beijing Normal University Beijing100875 China Zhuhai Branch of State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Zhuhai519087 China School of Atmospheric Sciences Guangdong Province Data Center of Terrestrial and Marine Ecosystems Carbon Cycle Sun Yat-sen University Guangdong Zhuhai510245 China Key Lab of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing101408 China International Institute for Earth System Sciences Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing University Jiangsu210023 China Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources School of Geography and Ocean Science Nanjing University Jiangsu210023 China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Study region: The Tibetan Plateau in China, the Third Pole of the *** focus: Accurate descriptions of spatial variation in evapotranspiration (ET) and its components on the Tibetan Plateau (TP) are crucial for understanding the dynamics of the regional water cycle and energy balance. However, how various environmental factors affect ET and its components remains unclear. This study addresses this gap using observational data from 14 sites and employing the Shuttleworth-Wallace-Hu (SWH) model to examine the spatial relationships between ET, its components, and underlying *** hydrological insights for the region: The SWH model parameters were optimized using the Monte Carlo method, achieving a satisfactory model performance with an average R² of 0.75. The ratio of transpiration to ET was generally higher in alpine meadows (0.55) than alpine steppes (0.39). Across the TP, precipitation and the leaf area index together shaped spatial variation in ET and transpiration. Precipitation emerged as the primary driver of interannual variation in ET, while the leaf area index strongly regulated the proportion of ET accounted for by transpiration. Furthermore, above aridity index values of 0.73, grassland ecosystems transitioned from water to energy. This finding is significant as it challenges the common application of an aridity index value of 0.65 to distinguish arid from humid regions. It suggests that TP grasslands, with an AI of 0.65-0.73, remain primarily water-limited. © 2024, The Authors. All rights reserved.

关键词： Biotic

Seasonal variation and human exposure characteristics of PBDEs in indoor dust, airborne particles and vapor phase in office environments

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Environmental Pollution 2025年 381卷 126581页

作者： Bayier Wulijia You Li Huan Tao Liang Wang Xiaoyong Liao Hongying Cao Dan Zhao Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences (CAS) Beijing 100101 China Beijing Key Laboratory of Environmental Damage Assessment and Remediation Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China State Environmental Protection Key Laboratory of Environmental Damage Identification and Restoration Beijing 100041 China Center for Environmental Risk and Damage Assessment Chinese Academy of Environmental Planning Beijing 100041 China

Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants and are prevalent indoors, yet long-term monitoring of indoor PBDEs remains rare. This study systematically investigated the seasonal variations, compositional profiles, and exposure risks of PBDEs across three indoor media—airborne particles (APs, n = 28), vapor phase (n = 28), and dust (n = 47)—collected from four offices. Seasonal trends of PBDEs showed the highest concentrations in autumn and the lowest in winter in both the indoor vapor phase and dust. Correlation analysis revealed a significant negative correlation (p < 0.001) between indoor vapor BDE-17 and BDE-209, suggesting photodegradation of high-weight to low-weight BDEs. In APs, twelve PBDE congeners—excluding BDE-17 and 85—exhibited significant positive correlations (p < 0.05) with PM concentrations. Dust on glass surfaces showed strong correlations between penta-BDEs and octa-/deca-BDEs (r = 0.79). Risk assessments found that dust ingestion was the primary exposure pathway, with students exhibiting the highest total exposure. Dermal contact exposure reached its highest levels in summer, while inhalation, dermal absorption, and dust ingestion were highest in autumn. This study reveals significant seasonal variations in office PBDE concentrations and reinforces the importance of dust as a critical exposure pathway, providing a scientific basis for PBDEs pollution control and health protection strategies.

关键词： Daily intake Office environment Polybrominated diphenyl ethers Risk assessment Seasonal variation

Climatic and Biotic Controls of Evapotranspiration Across Grassland Ecosystems on Tibetan Plateau

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SSRN 2024年

作者： Peng, Siyuan Yang, Yue Luo, Dengnan Zeng, Xiang Liang, Minqi Tao, Long Zhang, Guangru Li, Pan Liao, Weijie Guo, Qun Cao, Ruochen Li, Yuzhe Zhang, Weirong Hu, Zhongmin School of Geography South China Normal University Shipai Campus Guangzhou510631 China Hainan Baoting Tropical Rainforest Ecosystem Observation and Research Station Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation School of Ecology and Environment Hainan University Haikou570228 China Center for Eco-Environment Restoration Engineering of Hainan Province Hainan University Haikou570228 China Facility of Geographical Science Beijing Normal University Beijing100875 China Zhuhai Branch of State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Zhuhai519087 China School of Atmospheric Sciences Guangdong Province Data Center of Terrestrial and Marine Ecosystems Carbon Cycle Sun Yat-sen University Guangdong Zhuhai510245 China Key Lab of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing101408 China International Institute for Earth System Sciences Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing University Jiangsu210023 China Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources School of Geography and Ocean Science Nanjing University Jiangsu210023 China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Understanding the spatial variations of evapotranspiration (ET) and its components on Tibetan Plateau (TP) is pivotal for grasping the regional water cycle and energy balance dynamics. Yet it is unclear how the changes of the intricate synergy among diverse environment factors significantly impacts the patterns of ET and its transformation state. Addressing this gap, this study employed observational data from 14 sites, utilizing the Shuttleworth-Wallace-Hu (SWH) model to investigate the spatial relationships between ET, its components, and influencing factors. Model parameters of SWH were optimized by Monte Carlo method, achieving a commendable simulation performance with a mean R2 value of 0.75. Our analysis reveals that in alpine meadow, the ratio of transpiration (T) to ET (T/ET) is generally higher (0.55) compared to alpine steppe (0.39). The T/ET values for hover around or below 0.5, indicating a balanced contribution of various ET components. Spatially, both PPT and LAI have an impact on ET and T/ET. PPT emerges as the primary driver of interannual spatial variations in ET, while LAI plays a crucial role in regulating T/ET. Our results further demonstrate that a transition from water-dominated to energy-dominated systems in TP grassland ecosystem at an approximately aridity index of 0.73. This is noteworthy considering the general application of an aridity index of 0.65 to delineate arid from humid regions. It implies that TP grasslands, within the 0.65-0.73 range, remain primarily water-driven. This insight holds substantial implications for comprehending water-energy dynamics in similar ecosystems, challenging the conventional binary categorization of arid and humid areas. Such findings are of immense significance in enhancing understanding of the intricate interactions of the water cycle between land and the atmosphere. © 2024, The Authors. All rights reserved.

关键词： Water supply

Households’ Climate Change Adaptation Strategies for Agriculture on the Eastern Tibetan Plateau

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Research Square

Research Square 2021年

作者： He, Xinjun Yan, Jianzhong Huang, Anyi Zhou, Hong Wu, Ya Yang, Liang Emlyn Paudel, Basanta State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land College of Resources and Environment Southwest University Chongqing400715 China Department of Geography Ludwig Maximilian University of Munich Munich Germany Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China

How agriculture can better adapt to climate change has been a key topic of interest for scholars. This study provides insights from the eastern agricultural region of the Tibetan Plateau (TP). The Yellow River-Huangshui River valley (YHV) is an important food-producing region on the TP. The agricultural production of small households has been affected by significant climate change and by a series of interventions on the part of the local government. Five main adaptation strategies adopted by households include crop rotation (86.71%), increasing agricultural inputs (74.21%), changing the sowing time of crops (61.51%), expanding cropland area (32.94%) and raising more livestock (16.27%) to adapt to the effects of climate change. Regression analysis revealed that households’ perceptions of climate change and five types of livelihood capital are important factors influencing their adoption of various livelihood strategies. In addition, the adaptation strategies used by households in the YHV are incremental adjustments to their existing production, while transformative adaptation strategies (e.g., irrigation facilities, improved crop varieties, agricultural insurance), which are larger in scale and could fundamentally reduce households’ vulnerability to climate change have been planned by the government. Due to the presence of government interventions, households in the YHV area are more proactive in adapting to climate change. Finally, the results of this paper are conducive to guiding the local government to enhance its intervention role to promote households’ climate change adaptation behavior. © 2021, CC BY.

关键词： Climate change