Pub Date : 2021-01-02DOI: 10.1080/04353676.2021.1893247
{"title":"Reviewer Summary for Geografiska Annaler: Series A, Physical Geography","authors":"","doi":"10.1080/04353676.2021.1893247","DOIUrl":"https://doi.org/10.1080/04353676.2021.1893247","url":null,"abstract":"","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"11 1","pages":"i - i"},"PeriodicalIF":1.5,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88606256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.1080/04353676.2020.1850064
J. Alean, Lea Schwendener, M. Zemp
ABSTRACT Boulders in the ablation areas of Alpine valley glaciers were found to not travel along with the ice in a passive manner only. Many show an additional but smaller component of movement towards the south. We investigate this phenomenon and its governing processes using field observations and measurements from terrestrial and aerial photographs of glaciers in the Swiss Alps. We found that large boulders can migrate from their medial moraine due to cyclic formation of classical glacier tables and also a similar process that produces ice tails. The main driving factors behind boulder migration are the size (and shape) of the boulder, ablation, radiation, and surface slope. On glaciers roughly oriented to the east or west, these processes result in a sorting of boulders from the supraglacial moraine towards the southern side, i.e. towards the sun. Future studies complementing our approach using a differential global positioning system should be able to better distinguish between the velocity components of ice flow and boulder migration, determine the precise azimuth of the latter, and investigate the potential influence on photogrammetric feature tracking.
{"title":"Migrating boulders on the surface of Alpine valley glaciers","authors":"J. Alean, Lea Schwendener, M. Zemp","doi":"10.1080/04353676.2020.1850064","DOIUrl":"https://doi.org/10.1080/04353676.2020.1850064","url":null,"abstract":"ABSTRACT Boulders in the ablation areas of Alpine valley glaciers were found to not travel along with the ice in a passive manner only. Many show an additional but smaller component of movement towards the south. We investigate this phenomenon and its governing processes using field observations and measurements from terrestrial and aerial photographs of glaciers in the Swiss Alps. We found that large boulders can migrate from their medial moraine due to cyclic formation of classical glacier tables and also a similar process that produces ice tails. The main driving factors behind boulder migration are the size (and shape) of the boulder, ablation, radiation, and surface slope. On glaciers roughly oriented to the east or west, these processes result in a sorting of boulders from the supraglacial moraine towards the southern side, i.e. towards the sun. Future studies complementing our approach using a differential global positioning system should be able to better distinguish between the velocity components of ice flow and boulder migration, determine the precise azimuth of the latter, and investigate the potential influence on photogrammetric feature tracking.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"26 1","pages":"151 - 166"},"PeriodicalIF":1.5,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75450939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-08DOI: 10.1080/04353676.2020.1854012
Yijin Zhao, Maierdang Keyimu, Zongshan Li, Yongzhe Chen, Jing Wei, Xiaochun Wang, Z. Fan
ABSTRACT Historical temperature reconstructions enable us to understand the long-term thermal variation feature of a region. We developed a tree-ring width chronology of the coniferous species Tsuga dumosa (D. Don) Eichler (Himalayan Hemlock) growing in the northern Gaoligong Mountains, northwestern Yunnan province of China. The climate-tree growth relationship analysis indicated that summer mean temperature was the main limiting factor of the radial growth of Himalayan Hemlock. Accordingly, using a linear regression model, we reconstructed the historical summer mean temperature time series spanning A.D. 1720–2005, which could account for 35.56% of the observedtemperature variance. Based on the reconstruction, the most obvious warme periods were identified as 1715–1730s, 1900–1910, 1920–1940 and 1980–2005, while the main cold episodes were 1740s–1750s, 1810s–1830s, 1910s–1920s and 1940s–1970s. Wavelet and correlation analyses indicated the existence of several interannual (2–4 years and 5.5 years) and decadal (8–12years) cycles in the variation of summer mean temperature, which probably related to El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and solar activity.
{"title":"Summer mean temperature reconstruction during the past 285 years based on tree-ring in northern Gaoligong Mountains, northwestern Yunnan of China","authors":"Yijin Zhao, Maierdang Keyimu, Zongshan Li, Yongzhe Chen, Jing Wei, Xiaochun Wang, Z. Fan","doi":"10.1080/04353676.2020.1854012","DOIUrl":"https://doi.org/10.1080/04353676.2020.1854012","url":null,"abstract":"ABSTRACT\u0000 Historical temperature reconstructions enable us to understand the long-term thermal variation feature of a region. We developed a tree-ring width chronology of the coniferous species Tsuga dumosa (D. Don) Eichler (Himalayan Hemlock) growing in the northern Gaoligong Mountains, northwestern Yunnan province of China. The climate-tree growth relationship analysis indicated that summer mean temperature was the main limiting factor of the radial growth of Himalayan Hemlock. Accordingly, using a linear regression model, we reconstructed the historical summer mean temperature time series spanning A.D. 1720–2005, which could account for 35.56% of the observedtemperature variance. Based on the reconstruction, the most obvious warme periods were identified as 1715–1730s, 1900–1910, 1920–1940 and 1980–2005, while the main cold episodes were 1740s–1750s, 1810s–1830s, 1910s–1920s and 1940s–1970s. Wavelet and correlation analyses indicated the existence of several interannual (2–4 years and 5.5 years) and decadal (8–12years) cycles in the variation of summer mean temperature, which probably related to El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and solar activity.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"131 1","pages":"69 - 82"},"PeriodicalIF":1.5,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74973106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-29DOI: 10.1080/04353676.2020.1840179
H. Purdie, P. Bealing, Christopher A. Gomez, B. Anderson, O. Marsh
ABSTRACT Fox Glacier/Te Moeka o Tuawe is a fast-responding maritime glacier that has undergone multiple advance and retreat phases during recent decades. Here we use a combination of repeat photography, Structure from Motion (SfM), and ice discharge measurement, to identify key morphological differences associated with these repeated phase changes, and assess how much of the current terminus is still dynamically active. Increasing surface-debris cover at the margins and topographic shading result in the asymmetry of the retreating terminus, with central portions receding faster than the margins. In 2019, the glacier is shorter than at any time in recorded history, and ice flux is insufficient to sustain the current glacier length, with a further ∼300 m of the glacier terminus region potentially vulnerable to retreat. However, due to the high climate sensitivity of this maritime glacier, even a slight shift towards increasing mass flux could see this trend reverse.
{"title":"Morphological changes to the terminus of a maritime glacier during advance and retreat phases: Fox Glacier/Te Moeka o Tuawe, New Zealand","authors":"H. Purdie, P. Bealing, Christopher A. Gomez, B. Anderson, O. Marsh","doi":"10.1080/04353676.2020.1840179","DOIUrl":"https://doi.org/10.1080/04353676.2020.1840179","url":null,"abstract":"ABSTRACT Fox Glacier/Te Moeka o Tuawe is a fast-responding maritime glacier that has undergone multiple advance and retreat phases during recent decades. Here we use a combination of repeat photography, Structure from Motion (SfM), and ice discharge measurement, to identify key morphological differences associated with these repeated phase changes, and assess how much of the current terminus is still dynamically active. Increasing surface-debris cover at the margins and topographic shading result in the asymmetry of the retreating terminus, with central portions receding faster than the margins. In 2019, the glacier is shorter than at any time in recorded history, and ice flux is insufficient to sustain the current glacier length, with a further ∼300 m of the glacier terminus region potentially vulnerable to retreat. However, due to the high climate sensitivity of this maritime glacier, even a slight shift towards increasing mass flux could see this trend reverse.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"38 1","pages":"167 - 185"},"PeriodicalIF":1.5,"publicationDate":"2020-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88455257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-17DOI: 10.1080/04353676.2020.1841410
Deliang Chen, Peng Zhang, Kristina Seftigen, T. Ou, M. Giese, R. Barthel
ABSTRACT Climate change poses additional risks for natural and human systems including the hydrological cycle, leading to altered temporal and spatial variation of hydroclimatic conditions. This work assessed the current understanding of the dryness and wetness conditions in Sweden over the last two millenniums based on proxy and instrumental data, as well as climate model simulations and projections until the end of the twenty-first century. The assessment represents a summary of the existing literature concerning analysis of four selected indices for dry/wet conditions relating to precipitation, potential evapotranspiration (PET), and soil moisture (SPEI, PDSI [including scPDSI], SPI, and AI). SPEI considers both precipitation and PET and can show hydroclimatic conditions at different time scales. Therefore, it was chosen to summarize the past and future changes. A focus is put on dry conditions, as drought has strong influences on groundwater which is an important freshwater resource for Sweden. The millennium historical perspective reveals that the current climate is relatively wet and the future would become even wetter as a general wetting trend started some 120 years ago. However, there have been and will be large variations of both dry and wet conditions on short time scales, especially on decadal and interannual time scales. Further, the changes since the 1950s show a regional pattern with most significant wetting in the north, a slightly overall wetting in the south but a drying in central-eastern part including the island of Gotland since 1981. This pattern is broadly consistent with climate model projections for the future.
{"title":"Hydroclimate changes over Sweden in the twentieth and twenty-first centuries: a millennium perspective","authors":"Deliang Chen, Peng Zhang, Kristina Seftigen, T. Ou, M. Giese, R. Barthel","doi":"10.1080/04353676.2020.1841410","DOIUrl":"https://doi.org/10.1080/04353676.2020.1841410","url":null,"abstract":"ABSTRACT Climate change poses additional risks for natural and human systems including the hydrological cycle, leading to altered temporal and spatial variation of hydroclimatic conditions. This work assessed the current understanding of the dryness and wetness conditions in Sweden over the last two millenniums based on proxy and instrumental data, as well as climate model simulations and projections until the end of the twenty-first century. The assessment represents a summary of the existing literature concerning analysis of four selected indices for dry/wet conditions relating to precipitation, potential evapotranspiration (PET), and soil moisture (SPEI, PDSI [including scPDSI], SPI, and AI). SPEI considers both precipitation and PET and can show hydroclimatic conditions at different time scales. Therefore, it was chosen to summarize the past and future changes. A focus is put on dry conditions, as drought has strong influences on groundwater which is an important freshwater resource for Sweden. The millennium historical perspective reveals that the current climate is relatively wet and the future would become even wetter as a general wetting trend started some 120 years ago. However, there have been and will be large variations of both dry and wet conditions on short time scales, especially on decadal and interannual time scales. Further, the changes since the 1950s show a regional pattern with most significant wetting in the north, a slightly overall wetting in the south but a drying in central-eastern part including the island of Gotland since 1981. This pattern is broadly consistent with climate model projections for the future.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"49 1","pages":"103 - 131"},"PeriodicalIF":1.5,"publicationDate":"2020-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78371844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-19DOI: 10.1080/04353676.2020.1832753
Yinfang Shi, Jun Zhao, P. Grace, Chuanhua Li, Jinglan Zhang, H. Du
ABSTRACT The use of GIS-based ecological models is increasing and the accuracy of input datasets of these models is improving. Still, there is a significant gap in quantifying the uncertainty related to the input data and the accuracy of these models’outputs. This study quantified error in annual cumulative temperature derived from using daily mean temperature and monthly mean temperature, and the uncertainty and error propagated in the Comprehensive and Sequential Classification System (CSCS) model that predicts Potential Natural Vegetation (PNV) in China. The error in annual cumulative temperature derived from daily mean temperature and monthly mean temperature is particularly high in Northwest and Northern China. The deviations in annual cumulative temperature have different effects on each PNV including edge effects on the model’s predictability due to error propagation in the interpolation method and overlay analysis. Future research can focus on the assessment of model behavior with the uncertainty of data itself and different spatial analysis methods including the spatial resolution of datasets. There is a need to develop a unique algorithm that would enable a better assessment of attribute error and location error in the spatial modeling.
{"title":"Uncertainties on the GIS based potential natural vegetation simulation using Comprehensive and Sequential Classification System","authors":"Yinfang Shi, Jun Zhao, P. Grace, Chuanhua Li, Jinglan Zhang, H. Du","doi":"10.1080/04353676.2020.1832753","DOIUrl":"https://doi.org/10.1080/04353676.2020.1832753","url":null,"abstract":"ABSTRACT The use of GIS-based ecological models is increasing and the accuracy of input datasets of these models is improving. Still, there is a significant gap in quantifying the uncertainty related to the input data and the accuracy of these models’outputs. This study quantified error in annual cumulative temperature derived from using daily mean temperature and monthly mean temperature, and the uncertainty and error propagated in the Comprehensive and Sequential Classification System (CSCS) model that predicts Potential Natural Vegetation (PNV) in China. The error in annual cumulative temperature derived from daily mean temperature and monthly mean temperature is particularly high in Northwest and Northern China. The deviations in annual cumulative temperature have different effects on each PNV including edge effects on the model’s predictability due to error propagation in the interpolation method and overlay analysis. Future research can focus on the assessment of model behavior with the uncertainty of data itself and different spatial analysis methods including the spatial resolution of datasets. There is a need to develop a unique algorithm that would enable a better assessment of attribute error and location error in the spatial modeling.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"187 1","pages":"186 - 198"},"PeriodicalIF":1.5,"publicationDate":"2020-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/04353676.2020.1832753","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72524431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1080/04353676.2020.1813982
E. Kalińska, H. Alexanderson, M. Krievāns
ABSTRACT In interstadial deposits, sand interbeds gain limited consideration in comparison with organic sediments, and therefore tend to be underrepresented in paleoenvironmental reconstructions. The Raunis site, central-eastern Latvia, is an example where organic beds have already gained some attention and been used to understand the complex interactions between advance and retreat of the Scandinavian Ice Sheet in the region. Sandy interlayers have so far not been investigated in detail and their time of deposition has also been unknown, therefore exploring these clastic-organic sediment alternation is of interest. This study provides a new set of luminescence datings along with sedimentological information from the character of individual quartz grains as detected from scanning electron microscope analysis. Sandy interlayers are dated to between 12 and 122 ka. Fast component OSL signal dominates in all investigated samples, but several samples have broad and/or skewed dose distributions. Only one sample is considered reliable and provides an age of 12.0 ± 0.6 ka. A radiocarbon age from organic sediments in the same unit yields an age of 14 025 ± 270 cal y BP. These two dates do not agree within 2 sigma, and this is likely related to reservoir and hard water effects of the radiocarbon sample. Sediments at the Raunis site fall into the Greenland Interstadial 1, but more detailed specification is not possible. The rest of the OSL ages are older than expected, likely due to incomplete bleaching during deposition. This means that stratigraphic reliability of this key site is likely hampered for further regional correlation.
在层间沉积中，与有机沉积物相比，砂互层得到的关注有限，因此在古环境重建中往往代表性不足。拉脱维亚中东部的劳尼斯遗址就是一个例子，在那里，有机床已经获得了一些关注，并被用来理解斯堪的纳维亚冰盖在该地区的进退之间复杂的相互作用。砂质夹层迄今尚未被详细研究，其沉积时间也未知，因此探索这些碎屑-有机沉积物的交替是一个有趣的问题。该研究提供了一套新的发光定年方法，并从扫描电镜分析的单个石英颗粒的特征中获得了沉积学信息。砂质夹层的年代在12 - 122ka之间。在所有研究样品中，快速组分OSL信号占主导地位，但一些样品具有广泛和/或倾斜的剂量分布。只有一个样品被认为是可靠的，提供了12.0±0.6 ka的年龄。同一单元有机沉积物的放射性碳年龄为14025±270 cal y BP。这两个数据在2 sigma范围内不一致，这可能与放射性碳样品的储层和硬水效应有关。劳尼斯地点的沉积物属于格陵兰岛1号间冰期，但不可能有更详细的说明。其余的OSL年龄比预期的要老，可能是由于沉积过程中的不完全漂白。这意味着这个关键地点的地层可靠性可能会阻碍进一步的区域对比。
{"title":"The Raunis section, central Latvia, revisited: first luminescence results and re-evaluation of a key Baltic States stratigraphic site","authors":"E. Kalińska, H. Alexanderson, M. Krievāns","doi":"10.1080/04353676.2020.1813982","DOIUrl":"https://doi.org/10.1080/04353676.2020.1813982","url":null,"abstract":"ABSTRACT In interstadial deposits, sand interbeds gain limited consideration in comparison with organic sediments, and therefore tend to be underrepresented in paleoenvironmental reconstructions. The Raunis site, central-eastern Latvia, is an example where organic beds have already gained some attention and been used to understand the complex interactions between advance and retreat of the Scandinavian Ice Sheet in the region. Sandy interlayers have so far not been investigated in detail and their time of deposition has also been unknown, therefore exploring these clastic-organic sediment alternation is of interest. This study provides a new set of luminescence datings along with sedimentological information from the character of individual quartz grains as detected from scanning electron microscope analysis. Sandy interlayers are dated to between 12 and 122 ka. Fast component OSL signal dominates in all investigated samples, but several samples have broad and/or skewed dose distributions. Only one sample is considered reliable and provides an age of 12.0 ± 0.6 ka. A radiocarbon age from organic sediments in the same unit yields an age of 14 025 ± 270 cal y BP. These two dates do not agree within 2 sigma, and this is likely related to reservoir and hard water effects of the radiocarbon sample. Sediments at the Raunis site fall into the Greenland Interstadial 1, but more detailed specification is not possible. The rest of the OSL ages are older than expected, likely due to incomplete bleaching during deposition. This means that stratigraphic reliability of this key site is likely hampered for further regional correlation.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"56 1","pages":"376 - 396"},"PeriodicalIF":1.5,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85224833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1080/04353676.2020.1809905
Brigitte Magori, P. Urdea, A. Onaca, F. Ardelean
ABSTRACT Little information exists regarding the geomorphologic characteristics, spatial distribution and genesis and activity of rock glaciers in the Balkan Peninsula. A total of 224 rock glaciers were identified in four major mountainous regions (Dinaric Alps, Rila and Pirin, North Macedonia, Pindus and Parnassus), covering a total of 16.74 km2. Most of the rock glaciers are considered relict and have fronts between 1412 and 2645 m. In the Balkan Peninsula, rock glaciers are not uniformly distributed, but rather concentrate in several mountain ranges (e.g. Pirin, Rila, Prokletije and Śar). Climate, elevation, aspect and lithology are the key factors controlling rock glaciers’ distribution in the study area. The vast majority of the rock glaciers (73%) are concentrated in the northern quadrant. Statistical analysis revealed that the size of the rock glaciers can be explained to a certain degree by the characteristics of the contributing area (e.g. its extent and elevation range), climate, aspect, altitude and slope. In Pirin Mountains the density of the rock glaciers and the mean specific area are considerably higher than in the other mountain ranges. Based on palaeoclimate reconstructions and climatological records we infer that at least three generations of rock glaciers developed in the Balkan Peninsula. It is hypothesized that above the 0°C isotherm of mean annual air temperature in the Rila and Pirin Mountains, intact rock glaciers may survive to present-day climatic conditions.
关于巴尔干半岛岩石冰川的地貌特征、空间分布、成因和活动等方面的研究很少。在4个主要山区(Dinaric Alps, Rila and Pirin, North Macedonia, Pindus and Parnassus)共确定了224个岩石冰川，总面积16.74 km2。大多数岩石冰川被认为是废弃的，其锋面在1412米到2645米之间。在巴尔干半岛，岩石冰川不是均匀分布的，而是集中在几个山脉(如Pirin、Rila、Prokletije和Śar)。气候、高程、坡向和岩性是控制研究区岩石冰川分布的关键因素。绝大多数岩石冰川(73%)集中在北部象限。统计分析表明，岩石冰川的大小可以在一定程度上由贡献区域(范围和高程范围)、气候、坡向、海拔和坡度等特征来解释。皮林山区的岩石冰川密度和平均比面积明显高于其他山脉。根据古气候重建和气候记录，我们推断巴尔干半岛至少发育了三代岩石冰川。据推测，在里拉山脉和皮林山脉的年平均气温0°C等温线以上，完整的岩石冰川可能存在于今天的气候条件下。
{"title":"Distribution and characteristics of rock glaciers in the Balkan Peninsula","authors":"Brigitte Magori, P. Urdea, A. Onaca, F. Ardelean","doi":"10.1080/04353676.2020.1809905","DOIUrl":"https://doi.org/10.1080/04353676.2020.1809905","url":null,"abstract":"ABSTRACT Little information exists regarding the geomorphologic characteristics, spatial distribution and genesis and activity of rock glaciers in the Balkan Peninsula. A total of 224 rock glaciers were identified in four major mountainous regions (Dinaric Alps, Rila and Pirin, North Macedonia, Pindus and Parnassus), covering a total of 16.74 km2. Most of the rock glaciers are considered relict and have fronts between 1412 and 2645 m. In the Balkan Peninsula, rock glaciers are not uniformly distributed, but rather concentrate in several mountain ranges (e.g. Pirin, Rila, Prokletije and Śar). Climate, elevation, aspect and lithology are the key factors controlling rock glaciers’ distribution in the study area. The vast majority of the rock glaciers (73%) are concentrated in the northern quadrant. Statistical analysis revealed that the size of the rock glaciers can be explained to a certain degree by the characteristics of the contributing area (e.g. its extent and elevation range), climate, aspect, altitude and slope. In Pirin Mountains the density of the rock glaciers and the mean specific area are considerably higher than in the other mountain ranges. Based on palaeoclimate reconstructions and climatological records we infer that at least three generations of rock glaciers developed in the Balkan Peninsula. It is hypothesized that above the 0°C isotherm of mean annual air temperature in the Rila and Pirin Mountains, intact rock glaciers may survive to present-day climatic conditions.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"9 1","pages":"354 - 375"},"PeriodicalIF":1.5,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89966234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-25DOI: 10.1080/04353676.2020.1822001
Khalid Omar Murtaza, S. Romshoo
ABSTRACT In this study, the lichenometry studies of the Hoksar Glacier valley in Kashmir Himalaya, India supported by the extensive ground- and remote sensing-based glacial geomorphological mapping enabled the identification of the six episodes of glacier advances in the valley. Field-based geomorphologic evidence suggests that the glacial episode 1 (GEI) experienced the most extensive glaciation in the Hoksar valley extending ∼1 km down the valley (altitude 3565 m) from the current snout position of the Hoksar Glacier (altitude 3680m). Lichenometric dating of the moraines suggests that the GE1 episode is chronologically the oldest (∼480 ± 25 years) and GE6 episode the youngest (∼245 ± 10 years). The mean equilibrium line altitude (ELA) during the GE1 episode was calculated as 3755 ± 4 m compared to the observed present ELA position of 4060 ± 5 m, an upward shift of 305 m observed during the period. The spatio-temporal changes of the Hoksar Glacier during different episodes of the glacier advances until 2018 showed that the glacier area has shrunk from ∼212 ha during the GE1 to 100 ha at present losing an area of 112 ha (52%) during the period mainly as a result of the recent climate change. The recent observed glacier recession (1980–2018) is much higher (11 000 m2 a−1) compared to the past recession (1300 m2 a−1). The study provides valuable insights about the glacier recession in the Kashmir Himalayan region during the Late Holocene where knowledge about the past glacial history on a regional scale is generally poorly investigated.
{"title":"Applications of glacial geomorphological and lichenometric studies for reconstructing the Late Holocene glacial history of the Hoksar valley, Kashmir Himalaya, India","authors":"Khalid Omar Murtaza, S. Romshoo","doi":"10.1080/04353676.2020.1822001","DOIUrl":"https://doi.org/10.1080/04353676.2020.1822001","url":null,"abstract":"ABSTRACT In this study, the lichenometry studies of the Hoksar Glacier valley in Kashmir Himalaya, India supported by the extensive ground- and remote sensing-based glacial geomorphological mapping enabled the identification of the six episodes of glacier advances in the valley. Field-based geomorphologic evidence suggests that the glacial episode 1 (GEI) experienced the most extensive glaciation in the Hoksar valley extending ∼1 km down the valley (altitude 3565 m) from the current snout position of the Hoksar Glacier (altitude 3680m). Lichenometric dating of the moraines suggests that the GE1 episode is chronologically the oldest (∼480 ± 25 years) and GE6 episode the youngest (∼245 ± 10 years). The mean equilibrium line altitude (ELA) during the GE1 episode was calculated as 3755 ± 4 m compared to the observed present ELA position of 4060 ± 5 m, an upward shift of 305 m observed during the period. The spatio-temporal changes of the Hoksar Glacier during different episodes of the glacier advances until 2018 showed that the glacier area has shrunk from ∼212 ha during the GE1 to 100 ha at present losing an area of 112 ha (52%) during the period mainly as a result of the recent climate change. The recent observed glacier recession (1980–2018) is much higher (11 000 m2 a−1) compared to the past recession (1300 m2 a−1). The study provides valuable insights about the glacier recession in the Kashmir Himalayan region during the Late Holocene where knowledge about the past glacial history on a regional scale is generally poorly investigated.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"32 1","pages":"51 - 68"},"PeriodicalIF":1.5,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76747940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-14DOI: 10.1080/04353676.2020.1813985
F. S. Sigurmundsson, G. Gísladóttir, E. Erlendsson
ABSTRACT Past human land-use is increasingly recognized as a driver of ecosystem change in seemingly natural landscapes. Quantification of historical land use is therefore critical for assessing the degree of human impact and requires integration of geography, ecology and history. This paper examines the impact of climate change, land-use and exposure to international markets on the terrestrial ecology in Suðursveit, in southeast Iceland between AD 1700 and 1901. For this we use historical data concerning land-use, livestock and demography, and mapping of glacier advance, glacier outburst floods (jökulhlaups) and agricultural land. Change in land-use or population during the eighteenth century was insignificant. Population declined in the first two decades of the nineteenth century due to the advance of Breiðamerkurjökull glacier. After AD 1820, Suðursveit became part of international market for agricultural products, which facilitated population and livestock increase. This led to overgrazing and severe land degradation in the nineteenth century.
{"title":"The roles of agriculture and climate in land degradation in southeast Iceland AD 1700–1900","authors":"F. S. Sigurmundsson, G. Gísladóttir, E. Erlendsson","doi":"10.1080/04353676.2020.1813985","DOIUrl":"https://doi.org/10.1080/04353676.2020.1813985","url":null,"abstract":"ABSTRACT Past human land-use is increasingly recognized as a driver of ecosystem change in seemingly natural landscapes. Quantification of historical land use is therefore critical for assessing the degree of human impact and requires integration of geography, ecology and history. This paper examines the impact of climate change, land-use and exposure to international markets on the terrestrial ecology in Suðursveit, in southeast Iceland between AD 1700 and 1901. For this we use historical data concerning land-use, livestock and demography, and mapping of glacier advance, glacier outburst floods (jökulhlaups) and agricultural land. Change in land-use or population during the eighteenth century was insignificant. Population declined in the first two decades of the nineteenth century due to the advance of Breiðamerkurjökull glacier. After AD 1820, Suðursveit became part of international market for agricultural products, which facilitated population and livestock increase. This led to overgrazing and severe land degradation in the nineteenth century.","PeriodicalId":55112,"journal":{"name":"Geografiska Annaler Series A-Physical Geography","volume":"27 1","pages":"132 - 150"},"PeriodicalIF":1.5,"publicationDate":"2020-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87762946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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