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| 2. |
- Ehlers, Todd A., et al.
(author)
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Past, present, and future geo-biosphere interactions on the Tibetan Plateau and implications for permafrost
- 2022
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In: Earth-Science Reviews. - : Elsevier BV. - 0012-8252. ; 234
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Journal article (peer-reviewed)abstract
- Interactions between the atmosphere, biosphere, cryosphere, hydrosphere, and geosphere are most active in the critical zone, a region extending from the tops of trees to the top of unweathered bedrock. Changes in one or more of these spheres can result in a cascade of changes throughout the system in ways that are often poorly understood. Here we investigate how past and present climate change have impacted permafrost, hydrology, and ecosystems on the Tibetan Plateau. We do this by compiling existing climate, hydrologic, cryosphere, biosphere, and geologic studies documenting change over decadal to glacial-interglacial timescales and longer. Our emphasis is on showing present-day trends in environmental change and how plateau ecosystems have largely flourished under warmer and wetter periods in the geologic past. We identify two future pathways that could lead to either a favorable greening or unfavorable degradation and desiccation of plateau ecosystems. Both paths are plausible given the available evidence. We contend that the key to which pathway future generations experience lies in what, if any, human intervention measures are implemented. We conclude with suggested management strategies that can be implemented to facilitate a future greening of the Tibetan Plateau.
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| 3. |
- Wartenburger, Richard, et al.
(author)
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Evapotranspiration simulations in ISIMIP2a-Evaluation of spatio-temporal characteristics with a comprehensive ensemble of independent datasets
- 2018
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In: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 13:7
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Journal article (peer-reviewed)abstract
- Actual land evapotranspiration (ET) is a key component of the global hydrological cycle and an essential variable determining the evolution of hydrological extreme events under different climate change scenarios. However, recently available ET products show persistent uncertainties that are impeding a precise attribution of human-induced climate change. Here, we aim at comparing a range of independent global monthly land ET estimates with historical model simulations from the global water, agriculture, and biomes sectors participating in the second phase of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP2a). Among the independent estimates, we use the EartH2Observe Tier-1 dataset (E2O), two commonly used reanalyses, a pre-compiled ensemble product (LandFlux-EVAL), and an updated collection of recently published datasets that algorithmically derive ET from observations or observations-based estimates (diagnostic datasets). A cluster analysis is applied in order to identify spatio-temporal differences among all datasets and to thus identify factors that dominate overall uncertainties. The clustering is controlled by several factors including the model choice, the meteorological forcing used to drive the assessed models, the data category (models participating in the different sectors of ISIMIP2a, E2O models, diagnostic estimates, reanalysis-based estimates or composite products), the ET scheme, and the number of soil layers in the models. By using these factors to explain spatial and spatio-temporal variabilities in ET, we find that the model choice mostly dominates (24%-40% of variance explained), except for spatio-temporal patterns of total ET, where the forcing explains the largest fraction of the variance (29%). The most dominant clusters of datasets are further compared with individual diagnostic and reanalysis-based estimates to assess their representation of selected heat waves and droughts in the Great Plains, Central Europe and western Russia. Although most of the ET estimates capture these extreme events, the generally large spread among the entire ensemble indicates substantial uncertainties.
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| 4. |
- Arheimer, Berit, et al.
(author)
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The IAHS Science for Solutions decade, with Hydrology Engaging Local People IN a Global world (HELPING)
- 2024
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In: Hydrological Sciences Journal. - 0262-6667 .- 2150-3435.
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Journal article (peer-reviewed)abstract
- The new scientific decade (2023-2032) of the International Association of Hydrological Sciences (IAHS) aims at searching for sustainable solutions to undesired water conditions - may it be too little, too much or too polluted. Many of the current issues originate from global change, while solutions to problems must embrace local understanding and context. The decade will explore the current water crises by searching for actionable knowledge within three themes: global and local interactions, sustainable solutions and innovative cross-cutting methods. We capitalise on previous IAHS Scientific Decades shaping a trilogy; from Hydrological Predictions (PUB) to Change and Interdisciplinarity (Panta Rhei) to Solutions (HELPING). The vision is to solve fundamental water-related environmental and societal problems by engaging with other disciplines and local stakeholders. The decade endorses mutual learning and co-creation to progress towards UN sustainable development goals. Hence, HELPING is a vehicle for putting science in action, driven by scientists working on local hydrology in coordination with local, regional, and global processes.
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| 5. |
- Blösch, Günter, et al.
(author)
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Twenty-three unsolved problems in hydrology (UPH) - a community perspective
- 2019
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In: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 64:10, s. 1141-1158
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Journal article (peer-reviewed)abstract
- This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come.
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| 6. |
- Campana, Pietro Elia, et al.
(author)
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Optimal grassland locations for sustainable photovoltaic water pumping systems in China
- 2015
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In: CLEAN, EFFICIENT AND AFFORDABLE ENERGY FOR A SUSTAINABLE FUTURE. - : Elsevier. ; 75, s. 301-307
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Conference paper (peer-reviewed)abstract
- Grassland is of strategic importance for food security of China because of the high number of livestock raised in those areas. Grassland degradation due to climate change and overgrazing is thus regarded as severe environmental and economic threat for a sustainable future development of China. Photovoltaic water pumping (PVWP) systems for irrigation can play an important role for the conservation of grassland areas, halting degradation, improving its productivity and farmers' income and living conditions. The aim of this paper is to identify the technically suitable grassland areas for the implementation of PVWP systems by assessing spatial data on land cover and slope, precipitation, potential evapotranspiration and water stress index. Furthermore, the optimal locations for installing PVWP systems have been assessed using a spatially explicit renewable energy systems optimization model based on the minimization of the cost of the whole supply chain. The results indicate that the PVWP-supported grassland areas show high potential in terms of improving forage productivity to contribute to supplying the local demand. Nevertheless, the optimal areas are highly sensitive to several environmental and economic parameters such as ground water depth, forage water requirements, forage price and CO2 emission costs. These parameters need to be carefully considered in the planning process to meet the forage yield potentials. (C) 2015 The Authors. Published by Elsevier Ltd.
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| 7. |
- Caretta, Martina Angela, et al.
(author)
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Water
- 2022
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In: Climate Change 2022: Impacts, Adaptation and Vulnerability : Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change - Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.
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Book chapter (other academic/artistic)
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| 8. |
- Gong, Guoqing, et al.
(author)
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Anomalous Water Vapor Circulation in an Extreme Drought Event of the Mid-Reaches of the Lancang-Mekong River Basin
- 2024
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In: EARTHS FUTURE. - 2328-4277. ; 12:8
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Journal article (peer-reviewed)abstract
- The middle reaches of the Lancang-Mekong River Basin (M-LMRB) experienced a record-breaking drought event in 2019, resulting in significant economic losses of approximately 650 million dollars and affecting a population of 17 million. However, the anomalous circulation and transportation processes of water vapor, which may have played a crucial role in inducing the extreme drought, have not been fully studied. In this study, we analyze the water vapor circulation during the 2019 drought event using the land-atmosphere water balance and a backward trajectory model for moisture tracking. Our results indicate that the precipitation in the M-LMRB from May to October 2019 was only 71.9% of the long-term climatological mean (1959-2021). The low precipitation during this drought event can be attributed to less-than-normal external water vapor supply. Specifically, the backward trajectory model reveals a decrease in the amount of water vapor transported from the Indian Ocean, the Bay of Bengal, and the Pacific Ocean, which are the main moisture sources for precipitation in the region. Comparing the atmospheric circulation patterns in 2019 with the climatology, we identify anomalous anticyclone conditions in the Bay of Bengal, anomalous westerlies in the Northeast Indian Ocean, and an anomalous cyclone in the Western Pacific Ocean, collectively facilitating a stronger export of water vapor from the region. Therefore, the dynamic processes played a more significant role than thermodynamic processes in contributing to the 2019 extreme drought event. In 2019, a record-breaking drought hit the M-LMRB, leading to significant economic losses and affecting a large population. This study explores the water vapor circulation during this drought using land-atmosphere water balance and a backward trajectory model. Findings show that precipitation from May to October 2019 was only seventy percent of the average from 1959 to 2021. The drought's severity was mainly due to a lack of water vapor from key sources: the Indian Ocean, the Bay of Bengal, and the Pacific Ocean. Anomalous weather patterns-an anticyclone in the Bay of Bengal, unusual westerlies in the Northeast Indian Ocean, and a cyclone in the Western Pacific-led to a significant reduction in water vapor reaching the region. This indicates that dynamic atmospheric processes played a larger role in causing the extreme drought than thermodynamic ones. These insights help improve understanding and prediction of droughts in Southeast Asia, particularly under changing climate conditions. Reduced external water vapor transport primarily leads to negative precipitation anomalies There has been a reduction in water vapor originating from the Indian Ocean, Bay of Bengal, and Pacific Ocean The reduction in water vapor transport is primarily influenced by dynamic factors rather than thermodynamic ones
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| 9. |
- Guan, Yanlong, et al.
(author)
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Elevation Regulates the Response of Climate Heterogeneity to Climate Change
- 2024
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In: GEOPHYSICAL RESEARCH LETTERS. - 0094-8276 .- 1944-8007. ; 51:12
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Journal article (peer-reviewed)abstract
- Climate change represents a profound threat to the diversity and stability of global climate zones. However, the complex interplay between climate change and elevation in shaping climate heterogeneity is not yet fully understood. Here, we combine Shannon's diversity index (SHDI) with the K & ouml;ppen-Geiger climate classification to explore the altitudinal distributions of global climate heterogeneity; and their responses to climate change. The study reveals a distinctive pattern: SHDI, a proxy for climate heterogeneity tends to slow down or decline at lower elevations with increasing temperatures, while at higher elevations, it continues to rise due to continuing cold conditions. Examination of climate simulations, both with and without anthropogenic forcing, confirms that observed changes in climate heterogeneity are primarily attributable to anthropogenic climate change within these high-elevation regions. This study underscores the importance of high-elevation regions as not only custodians of diverse climate types but also potential refuges for species fleeing warmer climates. Climate change is threatening the diversity and stability of global climate patterns. But we're still not completely sure how climate change interacts with elevation to affect climate heterogeneity. In this study, we looked at how climate heterogeneity changes with altitude and responds to climate change. We found that as temperatures rise, the climate diversity tends to decrease at lower elevations, but it increases at higher elevations. We used climate simulations to show that these changes can be attributed to anthropogenic climate change. This study shows that high-elevation regions are important because they can sustain diverse climates and are likely to be a safe haven for plants and animals when climate diversity continues to decline at lower elevations. We employed a high-resolution climate data set to analyze changes in global climate heterogeneity With increasing temperatures, global climate heterogeneity amplifies at higher elevations, while diminishing at lower altitudes Anthropogenic climate change primarily drives alterations in climate heterogeneity at higher elevations
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| 10. |
- Hou, Xuejiao, et al.
(author)
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Anthropogenic transformation of Yangtze Plain freshwater lakes: patterns, drivers and impacts
- 2020
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In: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257. ; 248
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Journal article (peer-reviewed)abstract
- Over the past half century, the Yangtze Plain of China has experienced rapid economic development. Lake reclamation (i.e., conversion of natural lake/wetland areas to agricultural/urban land or aquaculture, thereby reducing the area of natural waters) in particular has greatly contributed to meeting the increasing demands for food and urban development. However, until now, a comprehensive quantification and understanding of historical anthropogenic lacustrine exploitation in this region has been lacking, prohibiting assessment of the impacts of these activities. We used Landsat observations from 1973 to 2018 to track reclamation-induced changes in 112 large lakes (97.8% of the total lake area) in the Yangtze Plain. We show that 41.6% (6056.9 km2) of the total lake area has been reclaimed since the 1970s. The expansion of agricultural and built-up lands dominated the reclamation activities in the 1970s, while the increase of aquaculture zones has prevailed since the mid-1980s. Reclamation activities were closely connected to government policies and major socio-economic events and had strong impacts on lake hydrology, flood risk mitigation capacity, and water quality as revealed by satellite and in situ observations. This new quantitative understanding of anthropogenic reclamation and its associated impacts on Yangtze Plain freshwater lakes can underpin the development of strategies to reduce the impacts of lake reclamation on environmental quality. The study has also demonstrated the unique strength of using long-term series satellite images in tracking historical environmental changes in a substantial region of the world, and the methods used here are potentially extendable to other inland and coastal areas to understand similar human-environment interaction problems.
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