scholarly journals Spatial Analyses and Susceptibility Modeling of Thermokarst Lakes in Permafrost Landscapes along the Qinghai–Tibet Engineering Corridor

2021 ◽  
Vol 13 (10) ◽  
pp. 1974
Author(s):  
Guoan Yin ◽  
Jing Luo ◽  
Fujun Niu ◽  
Fujun Zhou ◽  
Xianglian Meng ◽  
...  
Keyword(s):  
Climate Change ◽  
Spatial Distribution ◽  
Summer Rainfall ◽  
Tibet Plateau ◽  
Grid Data ◽  
Ground Ice ◽  
Thermokarst Lakes ◽  
Susceptibility Modeling ◽  
Environmental Controls ◽  
Ice Content

Thermokarst lakes (TLs) caused by the thaw of massive ground ice in ice-rich permafrost landscapes are increasing and have strong impacts on the hydro–ecological environment and human infrastructure on the Qinghai–Tibet Plateau (QTP), however, its spatial distribution characteristics and environmental controls have not been underrepresented at the local scale. Here, we analyzed the spatial distribution of small TLs along the Qinghai–Tibet Engineering Corridor (QTEC) based on high-resolution (up to 2.0 m) satellite images. The TLs gathered in the plains and upland plateau and covered 8.3% of the QTEC land. We deployed a random-frost method to investigate the suitable environmental conditions for TLs. Climate including summer rainfall and the air temperature was the most important factor controlling the TL distribution, followed by topography and soil characteristics that affected the ground ice content. TL susceptibility was mapped based on the combinations of climate, soil, and topography grid data. On average, around 20% of the QTEC area was in a high to very-high-susceptibility zone that is likely to develop TLs in response to climate change. This study improved the understanding of controlling factors for TL development but also provided insights into the conditions of massive ground ice and was helpful to assess the impacts of climate change on ecosystem processes and engineering design.

scholarly journals The Impact of Permafrost Degradation on Lake Changes in the Endorheic Basin on the Qinghai–Tibet Plateau

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1287
Author(s):  
Wenhui Liu ◽  
Changwei Xie ◽  
Wu Wang ◽  
Guiqian Yang ◽  
Yuxin Zhang ◽  
...  
Keyword(s):  
Tibet Plateau ◽  
Permafrost Degradation ◽  
Ground Ice ◽  
Landsat Images ◽  
Temporal Area ◽  
Discontinuous Permafrost ◽  
Continuous Permafrost ◽  
Endorheic Basin ◽  
Ice Content ◽  
The Impact

Lakes on the Qinghai–Tibetan Plateau (QTP) have experienced significant changes, especially the prevailing lake expansion since 2000 in the endorheic basin. The influence of permafrost thawing on lake expansion is significant but rarely considered in previous studies. In this study, based on Landsat images and permafrost field data, the spatial-temporal area changes of lakes of more than 5 km2 in the endorheic basin on the QTP during 2000–2017 is examined and the impact of permafrost degradation on lake expansion is discussed. The main results are that permafrost characteristics and its degradation trend have close relationships with lake changes. Lake expansion in the endorheic basin showed a southwest–northeast transition from shrinking to stable to rapidly expanding, which corresponded well with the permafrost distribution from island-discontinuous to seasonally frozen ground to continuous permafrost. A dramatic lake expansion in continuous permafrost showed significant spatial differences; lakes expanded significantly in northern and eastern continuous permafrost with a higher ground ice content but slightly in southern continuous permafrost with a lower ground ice content. This spatial pattern was mainly attributed to the melting of ground ice in shallow permafrost associated with accelerating permafrost degradation. Whereas, some lakes in the southern zones of island-discontinuous permafrost were shrinking, which was mainly because the extended taliks arising from the intensified permafrost degradation have facilitated surface water and suprapermafrost groundwater discharge to subpermafrost groundwater and thereby drained the lakes. Based on observation and simulated data, the melting of ground ice at shallow depths below the permafrost table accounted for 21.2% of the increase in lake volume from 2000 to 2016.

scholarly journals Bacterial Communities Present Distinct Co-occurrence Networks in Sediment and Water of the Thermokarst Lakes in the Yellow River Source Area

2021 ◽  
Vol 12 ◽  
Author(s):  
Ze Ren ◽  
Cheng Zhang ◽  
Xia Li ◽  
Kang Ma ◽  
Zhe Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Bacterial Communities ◽  
Environmental Variables ◽  
Yellow River ◽  
Source Area ◽  
Tibet Plateau ◽  
Future Climate Change ◽  
The Yellow River ◽  
Thermokarst Lakes ◽  
Yellow River Source

Thermokarst lakes are a ubiquitous and important landscape feature in cold regions and are changing tremendously due to the accelerated climate change. In thermokarst lakes, sediment and water are two distinct but highly interconnected habitats, harboring different bacterial communities in terms of taxonomic composition. However, the co-occurrence networks of these bacterial communities remain unclear. Here, we investigate the co-occurrence ecological networks of sediment and water bacterial communities for thermokarst lakes in the Yellow River Source Area on the Qinghai-Tibet Plateau. The results show that the bacterial communities construct distinct co-occurrence networks in sediment and water. The metacommunity network was parsed into four major modules formed by the operational taxonomic units (OTUs) enriched in sediment or water independently, and water-enriched OTUs exhibited much closer interconnections than sediment-enriched OTUs. When considering the sediment and water bacterial networks separately, different topological properties and modular patterns present: the sediment bacterial network was more clustered while the modules less responded to the environmental variables. On the contrary, the water bacterial network was more complex with the OTUs more interconnected and its modules more responded to the environmental variables. Moreover, the results of the structural equation model suggest that, by the influence of environmental variations on individual modules, the water bacterial communities would be more vulnerable under the fact of accelerating climate change. This study provides insights beyond a conventional taxonomic perspective, adding our knowledge of the potential mechanisms structuring bacterial community assembly and improving our prediction of the responses of this fast-changing ecosystem to future climate change.

Cryostructures and ground ice content in ice-rich permafrost area of the Qinghai-Tibet Plateau with Computed Tomography Scanning

2021 ◽  
Vol 18 (5) ◽  
pp. 1208-1221
Author(s):  
Xing-wen Fan ◽  
Zhan-ju Lin ◽  
Ze-yong Gao ◽  
Xiang-lian Meng ◽  
Fu-jun Niu ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Tibet Plateau ◽  
Ground Ice ◽  
Computed Tomography Scanning ◽  
Ice Content ◽  
Qinghai Tibet Plateau ◽  
Tomography Scanning

North Atlantic Oscillation; a Climatic Indicator to Predict Hydropower Availability in Scandinavia

2002 ◽  
Vol 33 (5) ◽  
pp. 415-424 ◽  
Author(s):  
Cintia B. Uvo ◽  
Ronny Berndtsson
Keyword(s):  
Climate Change ◽  
Spatial Distribution ◽  
Climate Variability ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Winter Precipitation ◽  
Model Driven ◽  
The World ◽  
Hydropower Production ◽  
Precipitation And Temperature

Climate variability and climate change are of great concern to economists and energy producers as well as environmentalists as both affect the precipitation and temperature in many regions of the world. Among those affected by climate variability is the Scandinavian Peninsula. Particularly, its winter precipitation and temperature are affected by the variations of the so-called North Atlantic Oscillation (NAO). The objective of this paper is to analyze the spatial distribution of the influence of NAO over Scandinavia. This analysis is a first step to establishing a predictive model, driven by a climatic indicator such as NAO, for the available water resources of different regions in Scandinavia. Such a tool would be valuable for predicting potential of hydropower production one or more seasons in advance.

scholarly journals Spatial and Temporal Differences in Alpine Meadow, Alpine Steppe and All Vegetation of the Qinghai-Tibetan Plateau and Their Responses to Climate Change

2021 ◽  
Vol 13 (4) ◽  
pp. 669
Author(s):  
Hanchen Duan ◽  
Xian Xue ◽  
Tao Wang ◽  
Wenping Kang ◽  
Jie Liao ◽  
...  
Keyword(s):  
Climate Change ◽  
Alpine Meadow ◽  
Global Climate ◽  
Growing Season ◽  
Tibet Plateau ◽  
Vegetation Types ◽  
Analysis Method ◽  
Alpine Steppe ◽  
Qinghai Tibet Plateau ◽  
Variation Trends

Alpine meadow and alpine steppe are the two most widely distributed nonzonal vegetation types in the Qinghai-Tibet Plateau. In the context of global climate change, the differences in spatial-temporal variation trends and their responses to climate change are discussed. It is of great significance to reveal the response of the Qinghai-Tibet Plateau to global climate change and the construction of ecological security barriers. This study takes alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau as the research objects. The normalized difference vegetation index (NDVI) data and meteorological data were used as the data sources between 2000 and 2018. By using the mean value method, threshold method, trend analysis method and correlation analysis method, the spatial and temporal variation trends in the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau were compared and analyzed, and their differences in the responses to climate change were discussed. The results showed the following: (1) The growing season length of alpine meadow was 145~289 d, while that of alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau was 161~273 d, and their growing season lengths were significantly shorter than that of alpine meadow. (2) The annual variation trends of the growing season NDVI for the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau increased obviously, but their fluctuation range and change rate were significantly different. (3) The overall vegetation improvement in the Qinghai-Tibet Plateau was primarily dominated by alpine steppe and alpine meadow, while the degradation was primarily dominated by alpine meadow. (4) The responses between the growing season NDVI and climatic factors in the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau had great spatial heterogeneity in the Qinghai-Tibet Plateau. These findings provide evidence towards understanding the characteristics of the different vegetation types in the Qinghai-Tibet Plateau and their spatial differences in response to climate change.

scholarly journals Persistence of the Swiss Needle Cast Outbreak in Oregon Coastal Douglas-Fir and New Insights from Research and Monitoring

2021 ◽  
Author(s):  
David C Shaw ◽  
Gabriela Ritóková ◽  
Yung-Hsiang Lan ◽  
Doug B Mainwaring ◽  
Andrew Russo ◽  
...  
Keyword(s):  
Climate Change ◽  
Regional Scale ◽  
Emerging Diseases ◽  
Douglas Fir ◽  
Landscape Patterns ◽  
Needle Cast ◽  
Plantation Management ◽  
Environmental Controls ◽  
Swiss Needle Cast ◽  
Improvement Programs

Abstract Swiss needle cast (SNC), caused by Nothophaeocryptopus gaeumannii, is a foliage disease of Douglas-fir (Pseudotsuga menziesii), that reduces growth in native stands and exotic plantations worldwide. An outbreak of SNC began in coastal Oregon in the mid-1990s and has persisted since that time. Here we review the current state of knowledge after 24 years of research and monitoring, with a focus on Oregon, although the disease is significant in coastal Washington and has recently emerged in southwestern British Columbia. We present new insights into SNC distribution, landscape patterns, disease epidemiology and ecology, host-pathogen interactions, trophic and hydrologic influences, and the challenges of Douglas-fir plantation management in the presence of the disease. In Oregon, the SNC outbreak has remained geographically contained but has intensified. Finally, we consider the implications of climate change and other recently emerged foliage diseases on the future of Douglas-fir plantation management. Study Implications: Douglas-fir tree growers need to consider Swiss needle cast (SNC) and other emerging foliage diseases as SNC has not abated over the past 24 years, and along with other emerging diseases, it continues to pose a threat to Douglas-fir plantation productivity. Douglas-fir management in western Oregon remains important, such that a knowledge of disease impacts and effective silvicultural responses is key. Managers should carefully consider whether alternative species may be ecologically or economically beneficial in some situations while tree improvement programs must continue to breed for tolerance to SNC. Research shows that regional scale foliage disease outbreaks can result in trophic cascades and hydrologic changes that affects more than just the trees. The environmental controls on the SNC epidemic imply that climate change could strongly influence future directions of the outbreak, with the greatest threats to trees at higher elevations.

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