Pub Date : 2022-04-21DOI: 10.1080/02723646.2022.2068405
Supriya Ghosh, Prasanta Mandal, B. Bera
ABSTRACT Confluence of river channels plays a significant role in channel avulsion, flood plain evolution and dynamics of the fluvial system. The principal objectives of the present study are (i) to analyze the direction and degree of confluence shifting through the recent past (1955–2020) by applying geospatial techniques and (ii) to find out the probable causes of confluence dynamics of the Raidak river system within quaternary geological sites of a Himalayan foreland basin in West Bengal, India, applying fluvio-geomorphological and sedimentary bank facies. Modified Normalized Difference Water Index method is also used. The result shows that the Raidak-Sankosh confluence (RSC) shifted by 9.94 km of the total distance between 1955 and 2020, whereas Raidak-I-Torsa confluence (RTC) has shifted 4.29 km overall distance during the same period. Both confluences were shifted toward the south and south-east directions. Total erosion and accretion area at the proximity of RSC and RTC has been registered as 40.1 sq km and 47.57 sq km and 39.67 sq km and 37.99 sq km, respectively, for the 65-year period. The key factors of confluence dynamics are regular flood events and channel avulsion, non-cohesive bank materials and huge channel bed sedimentation with multiple bars.
{"title":"Geospatial and fluvio-geomorphological investigation of confluence dynamics of river Raidak within Himalayan foreland basin, India","authors":"Supriya Ghosh, Prasanta Mandal, B. Bera","doi":"10.1080/02723646.2022.2068405","DOIUrl":"https://doi.org/10.1080/02723646.2022.2068405","url":null,"abstract":"ABSTRACT Confluence of river channels plays a significant role in channel avulsion, flood plain evolution and dynamics of the fluvial system. The principal objectives of the present study are (i) to analyze the direction and degree of confluence shifting through the recent past (1955–2020) by applying geospatial techniques and (ii) to find out the probable causes of confluence dynamics of the Raidak river system within quaternary geological sites of a Himalayan foreland basin in West Bengal, India, applying fluvio-geomorphological and sedimentary bank facies. Modified Normalized Difference Water Index method is also used. The result shows that the Raidak-Sankosh confluence (RSC) shifted by 9.94 km of the total distance between 1955 and 2020, whereas Raidak-I-Torsa confluence (RTC) has shifted 4.29 km overall distance during the same period. Both confluences were shifted toward the south and south-east directions. Total erosion and accretion area at the proximity of RSC and RTC has been registered as 40.1 sq km and 47.57 sq km and 39.67 sq km and 37.99 sq km, respectively, for the 65-year period. The key factors of confluence dynamics are regular flood events and channel avulsion, non-cohesive bank materials and huge channel bed sedimentation with multiple bars.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45614674","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 : 2022-04-19DOI: 10.1080/02723646.2022.2064065
W. Imsong, G. T. Thong, Shubhra Sharma
ABSTRACT The Belt of Schuppen (BoS) of Nagaland is a NE-SW trending linear zone lying adjacent to the Brahmaputra Valley of Assam in Northeast India. Geomorphic, stratigraphic and chronologic data from the Dzüdza and Chathe river valleys that cut across the BoS have been studied to understand the influence of climate on landform evolution in parts of the BoS. Fluvial landforms in the Dzüdza and Chathe river valleys evolved in four major phases bracketed between 22–17 ka (Phase IV), 13–9.0 ka (Phase III), 7–5 ka (Phase II) and 3.5–1.5 ka (Phase I), indicating multi-centennial to millennial changes in monsoon intensity. Climatically, Phase-III was dominated by valley aggradation initiated by onset of the Indian Summer Monsoon (ISM) and persisted intermittently till the early Holocene-strengthened ISM. The other phases of aggradation are attributed to transient or weak ISM. The present study suggests that fluvial aggradation was associated with enhanced precipitation and sediment supply in the BoS valley, whereas the transient and weak ISM is manifested in episodic pulses of alluvial ingression from the tributaries to the trunk valleys; along with post depositional tectonic modifications of the landforms.
{"title":"Causes of pulsating evolution of fluvial landforms since the marine isotopic stage-2 in the belt of Schuppen, Nagaland, NE India","authors":"W. Imsong, G. T. Thong, Shubhra Sharma","doi":"10.1080/02723646.2022.2064065","DOIUrl":"https://doi.org/10.1080/02723646.2022.2064065","url":null,"abstract":"ABSTRACT The Belt of Schuppen (BoS) of Nagaland is a NE-SW trending linear zone lying adjacent to the Brahmaputra Valley of Assam in Northeast India. Geomorphic, stratigraphic and chronologic data from the Dzüdza and Chathe river valleys that cut across the BoS have been studied to understand the influence of climate on landform evolution in parts of the BoS. Fluvial landforms in the Dzüdza and Chathe river valleys evolved in four major phases bracketed between 22–17 ka (Phase IV), 13–9.0 ka (Phase III), 7–5 ka (Phase II) and 3.5–1.5 ka (Phase I), indicating multi-centennial to millennial changes in monsoon intensity. Climatically, Phase-III was dominated by valley aggradation initiated by onset of the Indian Summer Monsoon (ISM) and persisted intermittently till the early Holocene-strengthened ISM. The other phases of aggradation are attributed to transient or weak ISM. The present study suggests that fluvial aggradation was associated with enhanced precipitation and sediment supply in the BoS valley, whereas the transient and weak ISM is manifested in episodic pulses of alluvial ingression from the tributaries to the trunk valleys; along with post depositional tectonic modifications of the landforms.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46386444","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 : 2022-02-18DOI: 10.1080/02723646.2022.2042916
N. Teale, D. A. Robinson
ABSTRACT This paper examines precipitation associated with large-scale patterns of water vapor transport in the eastern United States. Daily 4 km gridded precipitation from PRISM (1981–2017) is sorted into a subset according to previously defined patterns of water vapor transport supplying the moisture on each day. These subsets are then analyzed to characterize the precipitation associated with each water vapor transport pattern. While each moisture transport pattern is associated with at least occasional precipitation, with seasonal variations, the highest precipitation averages are issued from near-coastal and coastal moisture transport patterns. Moisture transport patterns emanating from the Gulf of Mexico are associated with highest average precipitation inland. Each pattern has a spatially distinct contribution to annual and seasonal precipitation totals. The water vapor transport patterns of moderate intensity and moderate associated precipitation contribute the most to average annual precipitation. Most moisture transport patterns are associated with statistically significant increases in areas of very heavy precipitation (x ≥ 50 mm). By identifying which atmospheric moisture transport patterns are responsible for increasing areas of very heavy precipitation, and by characterizing the precipitation totals and contribution associated with each, this paper demonstrates the utility of examining precipitation variability through moisture transport patterns.
{"title":"Eastern US precipitation investigated through patterns of moisture transport","authors":"N. Teale, D. A. Robinson","doi":"10.1080/02723646.2022.2042916","DOIUrl":"https://doi.org/10.1080/02723646.2022.2042916","url":null,"abstract":"ABSTRACT This paper examines precipitation associated with large-scale patterns of water vapor transport in the eastern United States. Daily 4 km gridded precipitation from PRISM (1981–2017) is sorted into a subset according to previously defined patterns of water vapor transport supplying the moisture on each day. These subsets are then analyzed to characterize the precipitation associated with each water vapor transport pattern. While each moisture transport pattern is associated with at least occasional precipitation, with seasonal variations, the highest precipitation averages are issued from near-coastal and coastal moisture transport patterns. Moisture transport patterns emanating from the Gulf of Mexico are associated with highest average precipitation inland. Each pattern has a spatially distinct contribution to annual and seasonal precipitation totals. The water vapor transport patterns of moderate intensity and moderate associated precipitation contribute the most to average annual precipitation. Most moisture transport patterns are associated with statistically significant increases in areas of very heavy precipitation (x ≥ 50 mm). By identifying which atmospheric moisture transport patterns are responsible for increasing areas of very heavy precipitation, and by characterizing the precipitation totals and contribution associated with each, this paper demonstrates the utility of examining precipitation variability through moisture transport patterns.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48711860","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 : 2022-02-16DOI: 10.1080/02723646.2022.2032922
M. Özdemir, Hülya Kaymak, Enes Ertan Kulaksız
ABSTRACT In this study, the weathering forms on the andesite of volcanic Mount Ağın (1807 m) located within the borders of Afyonkarahisar province in the Central Western Anatolia part of the Aegean Region were investigated. The climatic characteristics of the study area, chemical and mineralogical-petrographic properties of the andesites, porosity, diaclase systems, and biogenic erosion cause formation of characteristic shape generations on the andesites. In the field, andesites have been weathered by mechanical effects based on salt crystallization, freeze-thaw, shrinkage-expansion, and by the chemical effects of waterbased on hydrolysis-hydration-oxidation. The weathering product formed as a result of differential weathering has been subsequently moved by erosion, and the unweathered parts came to the surface to form distinctive forms in the topography. Weathering forms seen on the andesites have been investigated in detail for the first time in Turkey. The aim of this study is to reveal the close relationship between erosional forms of “andesite topography” and the factors playing a significant role in the formation of these weathering features. According to field observations and laboratory analyses, the original weathering forms on the mass have been explored and classified, and consequently revealed their formation mechanism and morphometric properties.
{"title":"Weathering geomorphology of Mount Ağın Andesites located in cool humid environment in Afyonkarahisar/Turkey","authors":"M. Özdemir, Hülya Kaymak, Enes Ertan Kulaksız","doi":"10.1080/02723646.2022.2032922","DOIUrl":"https://doi.org/10.1080/02723646.2022.2032922","url":null,"abstract":"ABSTRACT In this study, the weathering forms on the andesite of volcanic Mount Ağın (1807 m) located within the borders of Afyonkarahisar province in the Central Western Anatolia part of the Aegean Region were investigated. The climatic characteristics of the study area, chemical and mineralogical-petrographic properties of the andesites, porosity, diaclase systems, and biogenic erosion cause formation of characteristic shape generations on the andesites. In the field, andesites have been weathered by mechanical effects based on salt crystallization, freeze-thaw, shrinkage-expansion, and by the chemical effects of waterbased on hydrolysis-hydration-oxidation. The weathering product formed as a result of differential weathering has been subsequently moved by erosion, and the unweathered parts came to the surface to form distinctive forms in the topography. Weathering forms seen on the andesites have been investigated in detail for the first time in Turkey. The aim of this study is to reveal the close relationship between erosional forms of “andesite topography” and the factors playing a significant role in the formation of these weathering features. According to field observations and laboratory analyses, the original weathering forms on the mass have been explored and classified, and consequently revealed their formation mechanism and morphometric properties.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46037785","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 : 2022-02-14DOI: 10.1080/02723646.2022.2035891
M. Moreno, M. Sugg, Camila Moreno, Dr. Johnathan Sugg, Dr. Baker L. Perry, J. Runkle, R. Leeper
ABSTRACT Droughts are a natural, recurrent climate extreme that can inflict long-lasting devastation on natural ecosystems and socio-economic sectors. Unlike other natural hazards, drought onset is insidious and often affects a greater spatial extent over a prolonged temporal scale. In the United States the evolution of drought and its impacts are typically region-specific and intensified precipitation variability may obscure how drought may manifest. In this study, we examine the spatiotemporal trends of drought using self-organizing maps (SOM), competitive learning subset of artificial neural networks (ANN), requiring unsupervised training of inputs. We introduced monthly Palmer Drought Severity Index (PDSI) values to the SOM to identify existing clusters of wetting and drying patterns from 1895 to 2016. After training, we created cartographic visualizations of the SOM output and conducted a subsequent time-series analysis to link with the geographic patterns of drought. Over the last 40 years, precipitation intensified in the Northeast, Midwest, and upper Great Plains across several nodes. Across the majority of SOM patterns, we identified no significant changes of drying or wetting patterns over the last century for the greater part of the CONUS.
{"title":"Examining spatiotemporal trends of drought in the conterminous United States using self-organizing maps","authors":"M. Moreno, M. Sugg, Camila Moreno, Dr. Johnathan Sugg, Dr. Baker L. Perry, J. Runkle, R. Leeper","doi":"10.1080/02723646.2022.2035891","DOIUrl":"https://doi.org/10.1080/02723646.2022.2035891","url":null,"abstract":"ABSTRACT Droughts are a natural, recurrent climate extreme that can inflict long-lasting devastation on natural ecosystems and socio-economic sectors. Unlike other natural hazards, drought onset is insidious and often affects a greater spatial extent over a prolonged temporal scale. In the United States the evolution of drought and its impacts are typically region-specific and intensified precipitation variability may obscure how drought may manifest. In this study, we examine the spatiotemporal trends of drought using self-organizing maps (SOM), competitive learning subset of artificial neural networks (ANN), requiring unsupervised training of inputs. We introduced monthly Palmer Drought Severity Index (PDSI) values to the SOM to identify existing clusters of wetting and drying patterns from 1895 to 2016. After training, we created cartographic visualizations of the SOM output and conducted a subsequent time-series analysis to link with the geographic patterns of drought. Over the last 40 years, precipitation intensified in the Northeast, Midwest, and upper Great Plains across several nodes. Across the majority of SOM patterns, we identified no significant changes of drying or wetting patterns over the last century for the greater part of the CONUS.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47650436","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 : 2022-01-10DOI: 10.1080/02723646.2021.2022339
D. Nag, B. Phartiyal, Pankaj Kumar, P. Joshi, Randheer Singh
ABSTRACT Gya river, one of the main tributary of Indus, hosts several scattered palaeoflood deposits. The chronology, genesis and spatiotemporal relationships of these scattered deposits can throw light to the regional and global climatic fluctuations and their implications for the evolution of the valley. The valley structure of the Gya river consists of a broad middle reach alternating with narrow valleys and gorges in the upper and lower reaches which can be blocked by the slightest of sediment discharge damming the entire valley. The geomorphological, sedimentological and chronological study in this valley reveals multiple short-lived lake phases at 21–19.9 ka, 13 ka and 4.5 ka in the broader reach of the river during the transition periods when climate rapidly fluctuates between cold-dry and warm-wet. The damming in the valley is the result of the glacial lake outbursts in the head waters of the Gya catchment blocking the narrow lower reaches of the main channel by massive sediment. These lakes that are formed by valley damming contains ~108 m3 of water which subsequently breach out causing significant geomorphic changes on reach scale along the Gya river channel.
{"title":"Geomorphological and sedimentological evidences of palaeo-outburst flood events from TanglangLa-Gya catchment of River Indus, Ladakh, India","authors":"D. Nag, B. Phartiyal, Pankaj Kumar, P. Joshi, Randheer Singh","doi":"10.1080/02723646.2021.2022339","DOIUrl":"https://doi.org/10.1080/02723646.2021.2022339","url":null,"abstract":"ABSTRACT Gya river, one of the main tributary of Indus, hosts several scattered palaeoflood deposits. The chronology, genesis and spatiotemporal relationships of these scattered deposits can throw light to the regional and global climatic fluctuations and their implications for the evolution of the valley. The valley structure of the Gya river consists of a broad middle reach alternating with narrow valleys and gorges in the upper and lower reaches which can be blocked by the slightest of sediment discharge damming the entire valley. The geomorphological, sedimentological and chronological study in this valley reveals multiple short-lived lake phases at 21–19.9 ka, 13 ka and 4.5 ka in the broader reach of the river during the transition periods when climate rapidly fluctuates between cold-dry and warm-wet. The damming in the valley is the result of the glacial lake outbursts in the head waters of the Gya catchment blocking the narrow lower reaches of the main channel by massive sediment. These lakes that are formed by valley damming contains ~108 m3 of water which subsequently breach out causing significant geomorphic changes on reach scale along the Gya river channel.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44848501","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 : 2022-01-10DOI: 10.1080/02723646.2022.2026075
Md Ariful Haque, Sharmin Shishir, Anannya Mazumder, M. Iqbal
ABSTRACT Spatio-temporal change detection analysis of Jamuna River using low and medium-resolution satellite data between the years of 1972 and 2013 are dynamic to assess river spatio-temporal changes and their impacts on the local settlements over the specific time. This study employs remote sensing and geographic information system (GIS) proficiencies to identify the river bank shifting, erosion, and depositional features along with the population displacement. The satellite image of LANDSAT multispectral (MSS), thematic mapper (TM), and operational land imager (OLI) and thermal infrared sensor (TIRS) were used in this study. Supervised and unsupervised classification techniques have been used to identify land cover types and detect the changes using ArcGIS Pro 2.3.2. Supervised classifications performed well by validating ≥90% overall accuracy. The result shows total erosion was 3356 ha from 1972 to 2013, while the deposition was 5342 ha. Erosion and deposition cause the bank line shifting, river widening, and settlement displacement. Hundreds of displaced people suffered from loss of land, livelihood, increased poverty, food insecurity, lack of sanitation, and drinking water facilities. Thus, this study will be earnest in assisting the environmental management and associated planning including necessary measures.
摘要利用1972年至2013年的中低分辨率卫星数据对贾穆纳河进行时空变化检测分析，以评估特定时间内河流的时空变化及其对当地居民点的影响。本研究利用遥感和地理信息系统（GIS）的熟练程度来识别河岸移动、侵蚀和沉积特征以及人口迁移。本研究使用了陆地卫星多光谱（MSS）、专题测绘仪（TM）、操作陆地成像仪（OLI）和热红外传感器（TIRS）的卫星图像。监督和非监督分类技术已用于识别土地覆盖类型，并使用ArcGIS Pro 2.3.2检测变化。监督分类通过验证≥90%的总体准确率表现良好。结果表明，从1972年到2013年，总侵蚀面积为3356公顷，而沉积面积为5342公顷。侵蚀和沉积导致河岸线偏移、河流拓宽和沉降位移。数百名流离失所者失去了土地、生计、贫困加剧、粮食不安全、缺乏卫生设施和饮用水设施。因此，本研究将认真协助环境管理和相关规划，包括必要的措施。
{"title":"Change detection of Jamuna River and its impact on the local settlements","authors":"Md Ariful Haque, Sharmin Shishir, Anannya Mazumder, M. Iqbal","doi":"10.1080/02723646.2022.2026075","DOIUrl":"https://doi.org/10.1080/02723646.2022.2026075","url":null,"abstract":"ABSTRACT Spatio-temporal change detection analysis of Jamuna River using low and medium-resolution satellite data between the years of 1972 and 2013 are dynamic to assess river spatio-temporal changes and their impacts on the local settlements over the specific time. This study employs remote sensing and geographic information system (GIS) proficiencies to identify the river bank shifting, erosion, and depositional features along with the population displacement. The satellite image of LANDSAT multispectral (MSS), thematic mapper (TM), and operational land imager (OLI) and thermal infrared sensor (TIRS) were used in this study. Supervised and unsupervised classification techniques have been used to identify land cover types and detect the changes using ArcGIS Pro 2.3.2. Supervised classifications performed well by validating ≥90% overall accuracy. The result shows total erosion was 3356 ha from 1972 to 2013, while the deposition was 5342 ha. Erosion and deposition cause the bank line shifting, river widening, and settlement displacement. Hundreds of displaced people suffered from loss of land, livelihood, increased poverty, food insecurity, lack of sanitation, and drinking water facilities. Thus, this study will be earnest in assisting the environmental management and associated planning including necessary measures.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43546923","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 : 2022-01-03DOI: 10.1080/02723646.2021.2020968
B. Young, M. Bishop
ABSTRACT Complex mountain geodynamics are difficult to decouple due to forcing factors, feedback mechanisms, and system couplings that arise from interacting atmospheric, surface, and tectonic processes. The operational-scale dependencies and process–form relationships that govern the spatio-temporal extent of process regimes, which in turn govern relief production, have yet to be adequately characterized and mapped. This research establishes a topographic morphological structural framework for representing and querying the spatial organizational structure of the topography that governs, and is governed by mountain geodynamics. The spatial scale-dependent structure of the topography is accounted for using land-surface parameters and land-surface partitioning into distinct terrain units that represent important aspects of the geomorphological system. The properties and spatial topology of terrain units provide constraints for modeling process–form relationships, which are represented as process–form indices and synthesized using logistic regression to empirically detect glacial and bedrock river incision process regimes at the basin-scale for 31 basins in the Central Karakoram at about 80% accuracy. The topographic morphological structural framework approach provides a mechanism for tractable representation of scale-dependent topographic structure for automated characterization of the land surface, providing insight into polygenetic geomorphological systems and systems coupling through defined process–form relationships.
{"title":"Mountain process regime characterization using a topographic morphological structural framework","authors":"B. Young, M. Bishop","doi":"10.1080/02723646.2021.2020968","DOIUrl":"https://doi.org/10.1080/02723646.2021.2020968","url":null,"abstract":"ABSTRACT Complex mountain geodynamics are difficult to decouple due to forcing factors, feedback mechanisms, and system couplings that arise from interacting atmospheric, surface, and tectonic processes. The operational-scale dependencies and process–form relationships that govern the spatio-temporal extent of process regimes, which in turn govern relief production, have yet to be adequately characterized and mapped. This research establishes a topographic morphological structural framework for representing and querying the spatial organizational structure of the topography that governs, and is governed by mountain geodynamics. The spatial scale-dependent structure of the topography is accounted for using land-surface parameters and land-surface partitioning into distinct terrain units that represent important aspects of the geomorphological system. The properties and spatial topology of terrain units provide constraints for modeling process–form relationships, which are represented as process–form indices and synthesized using logistic regression to empirically detect glacial and bedrock river incision process regimes at the basin-scale for 31 basins in the Central Karakoram at about 80% accuracy. The topographic morphological structural framework approach provides a mechanism for tractable representation of scale-dependent topographic structure for automated characterization of the land surface, providing insight into polygenetic geomorphological systems and systems coupling through defined process–form relationships.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46073110","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 : 2021-12-06DOI: 10.1080/02723646.2021.2008104
Jacob Laliberté, A. Langlois, A. Royer, Jean-Benoît Madore, F. Gauthier
ABSTRACT Considering the increased popularity for backcountry mountain recreation activities, potentially problematic snowpack interfaces are currently of great interest given their impact on snow stability. The identification of interface vertical locations and spatial variability in the snowpack is essential for avalanche danger forecasting. The Gaspé Peninsula specific climate often leads to a complex snowpack development, where the need of improved monitoring is important. The goal of this research is to assess an automated method to detect contrasted snow interfaces using a 24 GHz Frequency Modulated Continuous Wave (FMCW) portable radar. Based on different in-situ configurations, we compared the radar amplitude signals with in-situ snow geophysical measurements, including SnowMicroPenetrometer (SMP). Radar measurements have been done following two different protocols: (1) mobile radar looking-up and down in order to understand the radar-snow wave interactions and optimize its parameters for spatial variability assessment of contrasted snow layers and (2) fixed radar looking-up to evaluate its potential in monitoring snow stratigraphy temporal variability. Results show good agreements with compared validation data with 80% of manually identified interfaces detection and a vertical positioning error of 3 cm. The presented FMCW radar appears to have a good potential for spatial and temporal variability assessment of snowpack stratigraphy.
{"title":"Retrieving dry snow stratigraphy using a versatile low-cost frequency modulated continuous wave (FMCW) K-band radar","authors":"Jacob Laliberté, A. Langlois, A. Royer, Jean-Benoît Madore, F. Gauthier","doi":"10.1080/02723646.2021.2008104","DOIUrl":"https://doi.org/10.1080/02723646.2021.2008104","url":null,"abstract":"ABSTRACT Considering the increased popularity for backcountry mountain recreation activities, potentially problematic snowpack interfaces are currently of great interest given their impact on snow stability. The identification of interface vertical locations and spatial variability in the snowpack is essential for avalanche danger forecasting. The Gaspé Peninsula specific climate often leads to a complex snowpack development, where the need of improved monitoring is important. The goal of this research is to assess an automated method to detect contrasted snow interfaces using a 24 GHz Frequency Modulated Continuous Wave (FMCW) portable radar. Based on different in-situ configurations, we compared the radar amplitude signals with in-situ snow geophysical measurements, including SnowMicroPenetrometer (SMP). Radar measurements have been done following two different protocols: (1) mobile radar looking-up and down in order to understand the radar-snow wave interactions and optimize its parameters for spatial variability assessment of contrasted snow layers and (2) fixed radar looking-up to evaluate its potential in monitoring snow stratigraphy temporal variability. Results show good agreements with compared validation data with 80% of manually identified interfaces detection and a vertical positioning error of 3 cm. The presented FMCW radar appears to have a good potential for spatial and temporal variability assessment of snowpack stratigraphy.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46441270","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 : 2021-11-29DOI: 10.1080/02723646.2021.1980958
D. J. Martin, R. Pavlowsky, J. Bendix, T. Dogwiler, J. Hess
ABSTRACT This research investigates impacts of an extreme flood on recruitment and transport of large wood (LW) in sub-basins of the North Fork River, Missouri. Data collection took place two months after a >500 year flood to characterize LW conditions before natural recovery processes could obscure impacts. We used sites from previous LW studies in the region as reference to help identify flood impacts. Results showed 1) LW load volumes were no different than reference sites, but individual LW pieces comprised a greater percentage of the total load, 2) a high proportion of pieces at flood-impacted sites contained root wads, 3) transport capacity of the flood-impacted sites was high compared to reference sites, and 4) LW recruitment increased exponentially with flood magnitude. These results suggest that extreme floods have a significant impact on the composition of the LW load, and that geomorphic impacts of such floods may result in enhanced transport capacities. Based on these findings, we present two possible post-flood LW response/recovery scenarios; one in which elevated transport capacity serves to speed system recovery to the pre-flood LW regime, and one in which the enhanced LW piece composition results in a new post-flood LW regime with an enhanced load.
{"title":"Impacts of an extreme flood on large wood recruitment and transport processes","authors":"D. J. Martin, R. Pavlowsky, J. Bendix, T. Dogwiler, J. Hess","doi":"10.1080/02723646.2021.1980958","DOIUrl":"https://doi.org/10.1080/02723646.2021.1980958","url":null,"abstract":"ABSTRACT This research investigates impacts of an extreme flood on recruitment and transport of large wood (LW) in sub-basins of the North Fork River, Missouri. Data collection took place two months after a >500 year flood to characterize LW conditions before natural recovery processes could obscure impacts. We used sites from previous LW studies in the region as reference to help identify flood impacts. Results showed 1) LW load volumes were no different than reference sites, but individual LW pieces comprised a greater percentage of the total load, 2) a high proportion of pieces at flood-impacted sites contained root wads, 3) transport capacity of the flood-impacted sites was high compared to reference sites, and 4) LW recruitment increased exponentially with flood magnitude. These results suggest that extreme floods have a significant impact on the composition of the LW load, and that geomorphic impacts of such floods may result in enhanced transport capacities. Based on these findings, we present two possible post-flood LW response/recovery scenarios; one in which elevated transport capacity serves to speed system recovery to the pre-flood LW regime, and one in which the enhanced LW piece composition results in a new post-flood LW regime with an enhanced load.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45527529","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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