Glacial cirques are typical landscape features of mid-latitude mountain environments like the Central Pyrenees. Their morphology as well as their spatial distribution provides insights about past glaciers and climates...Glacial cirques are typical landscape features of mid-latitude mountain environments like the Central Pyrenees. Their morphology as well as their spatial distribution provides insights about past glaciers and climates. In this study, we examine the distribution, morphometrical and topographical characteristics of glacial cirques in two U-shaped glacial valleys located in the Central Pyrenees – the Aran and the Boí valleys. They are located in different aspects of this mountain range(north vs south) under different climatic influences that promoted distinct glaciation patterns during the late Pleistocene. The spatial mapping of these landforms was carried out using high-resolution imagery and field observations. We analysed the data of the morphometrical and topographical variables of the glacial cirques by using different statistical and geospatial methods in order tounveil the factors controlling their formation and development. A total of 186 glacial cirques were mapped in the study area, including 119 in the Aran and 67 in the Boí valleys. The local topography and microclimate conditions lead to substantial differences in both areas in terms of the morphology and dimensions of the cirques. Glacial cirques in Boí are distributed at slightly higher elevations than in Aran and they are also larger, though their dimensions decrease with elevation in both valleys. Aran cirques are mostly oriented NE, while Boí landforms do not show any prevailing aspect. Even though lithology does not control the distribution of the glacial cirques, some specific lithological settings may favour the development of larger cirques. In general, glacial cirques in the Aran and the Boí valleys show morphometrical properties similar to those reported in other mid-latitude mountain ranges.展开更多
We will never forget the feeling of glories that large theme acrobatic drama Mysterious Oriental City,which was continuously performed for over2000times in Florida,U.S.A.since1986,brought to us;andwe will never forget...We will never forget the feeling of glories that large theme acrobatic drama Mysterious Oriental City,which was continuously performed for over2000times in Florida,U.S.A.since1986,brought to us;andwe will never forget the feeling of happiness when this artistic attempt received thunderous applauds in aforeign country.The feeling of glories and happiness stimulates our love and esteem to the art ofacrobatics.It is because of this love that we endeavor to discuss the Chinese acrobatics following themeacrob...展开更多
Cirque glaciers found on the Colorado Front Range, USA are sensitive to climate change and are important for water supply and the delivery of water downstream. These glaciers are shrinking at a rapid rate in response ...Cirque glaciers found on the Colorado Front Range, USA are sensitive to climate change and are important for water supply and the delivery of water downstream. These glaciers are shrinking at a rapid rate in response to the global climate change, and thus it is important to track and analyze them. One of the ways to monitor these glaciers is by using multispectral satellite imagery (Landsat imagery). In this article, the feasibility of tracking glacial area via Landsat satellites has been discussed and the trend of 13 glaciers in the Colorado Front Range Region has been analyzed from 1993 to 2021. In this period, the total glacial area across 13 glaciers in the Colorado Front Range Region has decreased by 63.6%, and a significant correlation (p-value p < 0.05) found with the annual global average temperature indicates that the retraction of glaciers is likely a response to the global warming.展开更多
One of the issues that geomorphology researchers have focused on is to trace the geomorphic effects and the snow lines in the Quaternary glaciers in Iran. This research has been carried out in the valleys of the south...One of the issues that geomorphology researchers have focused on is to trace the geomorphic effects and the snow lines in the Quaternary glaciers in Iran. This research has been carried out in the valleys of the southern slopes of Alvand Kuh Mountains, namely the Serkan and Mobarakabad valleys. The equilibrium line altitude between current and ancient glaciers is one of the parameters that is used as a variation indicator of climate. There are several ways to rebuild this parameter (Ancient ELA). Equilibrium Line altitude requires the accurate knowledge of glacial geomorphic landforms and evidence. According to Kuhle, Hofer and Luis methods, providing and estimating the ancient and permanent snow lines were carried out in this research during field operations within several intervals and the glacial geomorphic evidences were identified such as circuses, sidebar moraines and terminal moraines. The six glacier subwatersheds were developed in a study area based on Kuhle, Hofer and Luis methods in which only two valleys of Serkan 3 and Mubarak Abad 3 had a high degree of accuracy in their ELA drop rate and old snow lines. It should be noted that the current snowlines of the current study area are 4400 m and 1400 m (based on the Schweitzer map). The results of the estimated snow lines for each of the six valleys are shown in Table 4. At the present study, the main of the Mobarak Abad valley area was divided to six glacial valleys which are called Serkan 1, 2, 3 and Mobarak Abad 1, 2, 3 and then several layers were provided, including cirque layers, moraine layers, primary and secondary crest layers, high crest layers, 10-meter DEM layer, highlight, different contour line layers and valleys profiles and finally, the ultimate map of glacial geomorphology of Serkan and Mobarak Abad valleys was prepared.展开更多
基金supported by the Research Group Climate Change and Environmental Systems(ZEPHYRUS)of the Institute of GeographySpatial Planning of the University of Lisbon+4 种基金a grant from the Erasmus+LLP Programme Grant funding the research stay of Luis Lopes at the University of Barcelonasupported by the Ramón y Cajal Program of the Spanish Ministry of Economy and Competitiveness(RYC-2015-17597)Financial support was also provided by the research group ANTALP(Antarctic,Arctic and Alpine environments,2017-SGR-1102)the PALEOGREEN(CTM2017-87976-P)CRONOANTAR(CTM2016-77878-P)projects of the Spanish Ministry of Economy and Competitiveness
文摘Glacial cirques are typical landscape features of mid-latitude mountain environments like the Central Pyrenees. Their morphology as well as their spatial distribution provides insights about past glaciers and climates. In this study, we examine the distribution, morphometrical and topographical characteristics of glacial cirques in two U-shaped glacial valleys located in the Central Pyrenees – the Aran and the Boí valleys. They are located in different aspects of this mountain range(north vs south) under different climatic influences that promoted distinct glaciation patterns during the late Pleistocene. The spatial mapping of these landforms was carried out using high-resolution imagery and field observations. We analysed the data of the morphometrical and topographical variables of the glacial cirques by using different statistical and geospatial methods in order tounveil the factors controlling their formation and development. A total of 186 glacial cirques were mapped in the study area, including 119 in the Aran and 67 in the Boí valleys. The local topography and microclimate conditions lead to substantial differences in both areas in terms of the morphology and dimensions of the cirques. Glacial cirques in Boí are distributed at slightly higher elevations than in Aran and they are also larger, though their dimensions decrease with elevation in both valleys. Aran cirques are mostly oriented NE, while Boí landforms do not show any prevailing aspect. Even though lithology does not control the distribution of the glacial cirques, some specific lithological settings may favour the development of larger cirques. In general, glacial cirques in the Aran and the Boí valleys show morphometrical properties similar to those reported in other mid-latitude mountain ranges.
文摘We will never forget the feeling of glories that large theme acrobatic drama Mysterious Oriental City,which was continuously performed for over2000times in Florida,U.S.A.since1986,brought to us;andwe will never forget the feeling of happiness when this artistic attempt received thunderous applauds in aforeign country.The feeling of glories and happiness stimulates our love and esteem to the art ofacrobatics.It is because of this love that we endeavor to discuss the Chinese acrobatics following themeacrob...
文摘Cirque glaciers found on the Colorado Front Range, USA are sensitive to climate change and are important for water supply and the delivery of water downstream. These glaciers are shrinking at a rapid rate in response to the global climate change, and thus it is important to track and analyze them. One of the ways to monitor these glaciers is by using multispectral satellite imagery (Landsat imagery). In this article, the feasibility of tracking glacial area via Landsat satellites has been discussed and the trend of 13 glaciers in the Colorado Front Range Region has been analyzed from 1993 to 2021. In this period, the total glacial area across 13 glaciers in the Colorado Front Range Region has decreased by 63.6%, and a significant correlation (p-value p < 0.05) found with the annual global average temperature indicates that the retraction of glaciers is likely a response to the global warming.
文摘One of the issues that geomorphology researchers have focused on is to trace the geomorphic effects and the snow lines in the Quaternary glaciers in Iran. This research has been carried out in the valleys of the southern slopes of Alvand Kuh Mountains, namely the Serkan and Mobarakabad valleys. The equilibrium line altitude between current and ancient glaciers is one of the parameters that is used as a variation indicator of climate. There are several ways to rebuild this parameter (Ancient ELA). Equilibrium Line altitude requires the accurate knowledge of glacial geomorphic landforms and evidence. According to Kuhle, Hofer and Luis methods, providing and estimating the ancient and permanent snow lines were carried out in this research during field operations within several intervals and the glacial geomorphic evidences were identified such as circuses, sidebar moraines and terminal moraines. The six glacier subwatersheds were developed in a study area based on Kuhle, Hofer and Luis methods in which only two valleys of Serkan 3 and Mubarak Abad 3 had a high degree of accuracy in their ELA drop rate and old snow lines. It should be noted that the current snowlines of the current study area are 4400 m and 1400 m (based on the Schweitzer map). The results of the estimated snow lines for each of the six valleys are shown in Table 4. At the present study, the main of the Mobarak Abad valley area was divided to six glacial valleys which are called Serkan 1, 2, 3 and Mobarak Abad 1, 2, 3 and then several layers were provided, including cirque layers, moraine layers, primary and secondary crest layers, high crest layers, 10-meter DEM layer, highlight, different contour line layers and valleys profiles and finally, the ultimate map of glacial geomorphology of Serkan and Mobarak Abad valleys was prepared.
