Pub Date : 2021-02-24DOI: 10.1080/02723646.2021.1890879
A. J. Orme, D. Orme
Dr Antony Ronald Orme (28 May 1936–30 May 2020), was the founding editor of Physical Geography. With his broad range of research interests from coastal geomorphology to pluvial lakes, Tony was comm...
{"title":"Introduction to special issue of physical geography in recognition of Dr. Tony Orme","authors":"A. J. Orme, D. Orme","doi":"10.1080/02723646.2021.1890879","DOIUrl":"https://doi.org/10.1080/02723646.2021.1890879","url":null,"abstract":"Dr Antony Ronald Orme (28 May 1936–30 May 2020), was the founding editor of Physical Geography. With his broad range of research interests from coastal geomorphology to pluvial lakes, Tony was comm...","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"1 1","pages":"1-6"},"PeriodicalIF":1.6,"publicationDate":"2021-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2021.1890879","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48928969","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 : 2021-02-16DOI: 10.1080/02723646.2021.1883802
L. Resler, J. T. Fry, Scotland Leman, J. Jelesko
ABSTRACT Understanding species distributions remains central to research in ecology and biogeography. Emphasis is placed on the spatial presence/absence of plants as related to underlying environmental factors; however, distributions result from both abiotic factors and adaptations to the abiotic environment. We analyzed poison ivy (Toxicodendron radicans (L.) Kuntze), which has high intraspecies variability in the plant functional trait of growth habit, to assess implications of plant strategies for spatial distributions. Our objectives were to: 1) determine whether anthropogenic habitats are statistically overrepresented in poison ivy incidence and growth habits (shrub, climbing liana, crawling liana), and 2) model biophysical parameters that constitute preferred poison ivy habitat and the three growth habits. We collected poison ivy field data along a trail-transect with corresponding geospatially indexed parameters, subsequently analyzed using Bayesian spatial modeling. Model results revealed poison ivy preference for human-modified habitat; Developed and Planted/Cultivated land use categories showed the largest marginal posterior probabilities for crawling and climbing lianas. Increasing temperature and elevation preferentially benefit the climbing growth habit. Our results suggest that variability in functional traits may impact species geographic distributions by expanding niche breadth. Incorporation of functional traits may thus advance predictive niche models of species distributions.
{"title":"Assessing poison ivy (Toxicodendron radicans) presence and functional traits in relation to land cover and biophysical factors","authors":"L. Resler, J. T. Fry, Scotland Leman, J. Jelesko","doi":"10.1080/02723646.2021.1883802","DOIUrl":"https://doi.org/10.1080/02723646.2021.1883802","url":null,"abstract":"ABSTRACT Understanding species distributions remains central to research in ecology and biogeography. Emphasis is placed on the spatial presence/absence of plants as related to underlying environmental factors; however, distributions result from both abiotic factors and adaptations to the abiotic environment. We analyzed poison ivy (Toxicodendron radicans (L.) Kuntze), which has high intraspecies variability in the plant functional trait of growth habit, to assess implications of plant strategies for spatial distributions. Our objectives were to: 1) determine whether anthropogenic habitats are statistically overrepresented in poison ivy incidence and growth habits (shrub, climbing liana, crawling liana), and 2) model biophysical parameters that constitute preferred poison ivy habitat and the three growth habits. We collected poison ivy field data along a trail-transect with corresponding geospatially indexed parameters, subsequently analyzed using Bayesian spatial modeling. Model results revealed poison ivy preference for human-modified habitat; Developed and Planted/Cultivated land use categories showed the largest marginal posterior probabilities for crawling and climbing lianas. Increasing temperature and elevation preferentially benefit the climbing growth habit. Our results suggest that variability in functional traits may impact species geographic distributions by expanding niche breadth. Incorporation of functional traits may thus advance predictive niche models of species distributions.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"43 1","pages":"614 - 637"},"PeriodicalIF":1.6,"publicationDate":"2021-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2021.1883802","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44988624","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 : 2021-02-15DOI: 10.1080/02723646.2021.1885788
Margarita E. McInnis, N. Pinter
ABSTRACT Uplifted coastal terraces are present on Santa Catalina Island, but so poorly preserved that researchers have debated for more than a century whether they even exist. Morphometric analyses of LIDAR-based topography on the California Channel Islands suggest that the poor expression of terraces on Catalina Island is due a combination of (1) geological conditions less conducive to terrace formation than on the other Channel Islands and (2) high landslide susceptibility around Catalina’s coastal margin that is erasing terrace morphology and deposits before they can reach the island's relatively un-dissected interior. Both of these factors seem to be related to the mechanical properties of the island’s predominant rock type, the Catalina Schist. Several of the other Channel Islands – such as Santa Barbara, San Clemente, Anacapa, and San Miguel Islands – have topography that is dominated by their terrace morphology, mostly by virtue of the small size of those islands. Of the large islands, Santa Rosa has the most extensive terraces, apparently driven by the prevalence of shallowly dipping sedimentary rock. Looking at terrace preservation generally, subhorizontal sedimentary units seem to represent an optimum between promoting the initial creation of wide terrace platforms and resistance to terrace erosion thereafter.
{"title":"Terrace formation and preservation: Santa Catalina Island and other California Channel Islands","authors":"Margarita E. McInnis, N. Pinter","doi":"10.1080/02723646.2021.1885788","DOIUrl":"https://doi.org/10.1080/02723646.2021.1885788","url":null,"abstract":"ABSTRACT Uplifted coastal terraces are present on Santa Catalina Island, but so poorly preserved that researchers have debated for more than a century whether they even exist. Morphometric analyses of LIDAR-based topography on the California Channel Islands suggest that the poor expression of terraces on Catalina Island is due a combination of (1) geological conditions less conducive to terrace formation than on the other Channel Islands and (2) high landslide susceptibility around Catalina’s coastal margin that is erasing terrace morphology and deposits before they can reach the island's relatively un-dissected interior. Both of these factors seem to be related to the mechanical properties of the island’s predominant rock type, the Catalina Schist. Several of the other Channel Islands – such as Santa Barbara, San Clemente, Anacapa, and San Miguel Islands – have topography that is dominated by their terrace morphology, mostly by virtue of the small size of those islands. Of the large islands, Santa Rosa has the most extensive terraces, apparently driven by the prevalence of shallowly dipping sedimentary rock. Looking at terrace preservation generally, subhorizontal sedimentary units seem to represent an optimum between promoting the initial creation of wide terrace platforms and resistance to terrace erosion thereafter.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"43 1","pages":"213 - 237"},"PeriodicalIF":1.6,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2021.1885788","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43595875","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 : 2021-02-11DOI: 10.1080/02723646.2021.1882074
P. Netopil, B. Šarapatka, Dawit Ayalew, Kateřina Drncová
ABSTRACT Evaluating erosion processes and their influence on soil degradation over extensive agricultural landscape is difficult. Because of the need for analysis and mapping of this problem, we elaborated a procedure applicable to a specific, intensively farmed, erosion-threatened chernozem area of CZ or similar regions. The aim of the research was to verify the possibility of digital aerial image analysis, along with a control study of soil sampling. To define and compare the boundaries and extent of erosion and deposition processes, we used images from two different years, showing changes in soil degradation. Orthorectification and unsupervised image classification were followed by interpretation and statistical evaluation. The results, locating erosional, transitional and depositional areas, were verified in laboratory analysis of soil samples for selected soil characteristics. Comparison of aerial images showed changes in the agricultural landscape over 35 years, showing an increase of ca. 60% in erosional areas. Extensive changes also occurred in transitional and depositional areas as material from the subsoil horizon of erosional areas covered some depositional areas. Importantly, our research confirmed the potential of digital aerial image analysis as a method of studying soil erosion over extensive landscape, and the possibility of using it in planning anti-erosion measures. GA
{"title":"Multi-temporal analysis of erosional plots using aerial images and deep soil probes","authors":"P. Netopil, B. Šarapatka, Dawit Ayalew, Kateřina Drncová","doi":"10.1080/02723646.2021.1882074","DOIUrl":"https://doi.org/10.1080/02723646.2021.1882074","url":null,"abstract":"ABSTRACT Evaluating erosion processes and their influence on soil degradation over extensive agricultural landscape is difficult. Because of the need for analysis and mapping of this problem, we elaborated a procedure applicable to a specific, intensively farmed, erosion-threatened chernozem area of CZ or similar regions. The aim of the research was to verify the possibility of digital aerial image analysis, along with a control study of soil sampling. To define and compare the boundaries and extent of erosion and deposition processes, we used images from two different years, showing changes in soil degradation. Orthorectification and unsupervised image classification were followed by interpretation and statistical evaluation. The results, locating erosional, transitional and depositional areas, were verified in laboratory analysis of soil samples for selected soil characteristics. Comparison of aerial images showed changes in the agricultural landscape over 35 years, showing an increase of ca. 60% in erosional areas. Extensive changes also occurred in transitional and depositional areas as material from the subsoil horizon of erosional areas covered some depositional areas. Importantly, our research confirmed the potential of digital aerial image analysis as a method of studying soil erosion over extensive landscape, and the possibility of using it in planning anti-erosion measures. GA","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"43 1","pages":"701 - 726"},"PeriodicalIF":1.6,"publicationDate":"2021-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2021.1882074","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59369983","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 : 2021-01-21DOI: 10.1080/02723646.2021.1875583
J. Winchester, R. Mahmood, W. Rodgers, P. Silva, N. Lovanh, J. Durkee, John H. Loughrin
ABSTRACT In the Southeastern U. S. there are Concentrated Animal Feeding Operations (CAFOs) that emit a variety of gases, including SO2. Sulfur is emitted as reduced sulfur compounds and can react in the atmosphere to produce SO2. It is expected that the concentration and spread of SO2 emissions from these sources would differ between wet and dry periods. In this research, SO2 emissions from locations representing CAFOs and its dispersion over the southeastern U.S. were simulated through sensitivity experiments using the Weather Research and Forecasting-Chemistry (WRF- Chem) model. Simulations were performed for dry periods and precipitation events that occurred over western Kentucky between July 7 and 13 July 2012. The study found that spatial coverage of SO2 dispersion originating from these locations was reduced during precipitation events and expanded during dry periods. The average concentration of SO2 over the study area was also higher during the breaks between precipitation events than during precipitation. The highest concentrations of SO2 exceeding 1,000 pptv remained within close range of the emission locations for the majority of the simulations, except for when local surface wind speeds were high. Most emissions from the locations remained limited to the surface and lower levels of the atmosphere (850 mb).
{"title":"A model-based exploratory study of sulfur dioxide dispersions from concentrated animal feeding operations in the Southeastern United States","authors":"J. Winchester, R. Mahmood, W. Rodgers, P. Silva, N. Lovanh, J. Durkee, John H. Loughrin","doi":"10.1080/02723646.2021.1875583","DOIUrl":"https://doi.org/10.1080/02723646.2021.1875583","url":null,"abstract":"ABSTRACT In the Southeastern U. S. there are Concentrated Animal Feeding Operations (CAFOs) that emit a variety of gases, including SO2. Sulfur is emitted as reduced sulfur compounds and can react in the atmosphere to produce SO2. It is expected that the concentration and spread of SO2 emissions from these sources would differ between wet and dry periods. In this research, SO2 emissions from locations representing CAFOs and its dispersion over the southeastern U.S. were simulated through sensitivity experiments using the Weather Research and Forecasting-Chemistry (WRF- Chem) model. Simulations were performed for dry periods and precipitation events that occurred over western Kentucky between July 7 and 13 July 2012. The study found that spatial coverage of SO2 dispersion originating from these locations was reduced during precipitation events and expanded during dry periods. The average concentration of SO2 over the study area was also higher during the breaks between precipitation events than during precipitation. The highest concentrations of SO2 exceeding 1,000 pptv remained within close range of the emission locations for the majority of the simulations, except for when local surface wind speeds were high. Most emissions from the locations remained limited to the surface and lower levels of the atmosphere (850 mb).","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"43 1","pages":"503 - 533"},"PeriodicalIF":1.6,"publicationDate":"2021-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2021.1875583","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45762505","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 : 2021-01-12DOI: 10.1080/02723646.2020.1868126
G. Griggs
ABSTRACT Coasts are among the most diverse environments on the Earth’s surface and are unique in being affected by the convergence of terrestrial, marine and atmospheric processes. The morphology of each individual segment of coastline is a result of the interaction between the tectonic setting and the properties of the materials making up the coast and the terrestrial and marine processes attacking the shoreline. Along the cliffed coast of central California, the combination of the structure and stratigraphy of the cliff-forming sedimentary rocks exerts a dominant influence on the coastal orientation, morphology and also erosion rates, which ultimately affects stability of all clifftop development. Graphical Abstract
{"title":"The importance of geologic structure and stratigraphy to cliff morphology and erosion along the northern Monterey Bay Coastline, Central California","authors":"G. Griggs","doi":"10.1080/02723646.2020.1868126","DOIUrl":"https://doi.org/10.1080/02723646.2020.1868126","url":null,"abstract":"ABSTRACT Coasts are among the most diverse environments on the Earth’s surface and are unique in being affected by the convergence of terrestrial, marine and atmospheric processes. The morphology of each individual segment of coastline is a result of the interaction between the tectonic setting and the properties of the materials making up the coast and the terrestrial and marine processes attacking the shoreline. Along the cliffed coast of central California, the combination of the structure and stratigraphy of the cliff-forming sedimentary rocks exerts a dominant influence on the coastal orientation, morphology and also erosion rates, which ultimately affects stability of all clifftop development. Graphical Abstract","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"42 1","pages":"495 - 512"},"PeriodicalIF":1.6,"publicationDate":"2021-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2020.1868126","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47149923","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 : 2021-01-10DOI: 10.1080/02723646.2021.1872857
V. Pandey, Anurag Tripathi, K. Sharma
ABSTRACT Landslide susceptibility is a dynamic phenomenon; it changes with slope intrinsic and transient factors. The study aims to evaluate the changes in the landslides, their size, location, and up to some extent, gradual stabilization impacts on susceptibility assessment. The majority of the models, which are developed to analyze landslide susceptibility, use landslide inventory as a dependent variable to compute the predictors’ significance. Therefore, a slight change in the landslide dataset nullifies the susceptibility zones. Thus, the landslide susceptibility maps become irrelevant to mitigate slope failures. In the present study, we have used two reference period landslide dataset to execute the landslide susceptibility analysis using the frequency ratio method. The model result was validated with a landslide test dataset using the area under the curve (AUC) method. The AUC value is 0.89 and 0.91 for 2013 and 2019, respectively. The study finds that annual updating of landslide inventory is essential for susceptibility modeling for assessment of associated risks and implications of mitigation measures along the highway corridor.
{"title":"Implications of landslide inventory in susceptibility modeling along a Himalayan highway corridor, India","authors":"V. Pandey, Anurag Tripathi, K. Sharma","doi":"10.1080/02723646.2021.1872857","DOIUrl":"https://doi.org/10.1080/02723646.2021.1872857","url":null,"abstract":"ABSTRACT Landslide susceptibility is a dynamic phenomenon; it changes with slope intrinsic and transient factors. The study aims to evaluate the changes in the landslides, their size, location, and up to some extent, gradual stabilization impacts on susceptibility assessment. The majority of the models, which are developed to analyze landslide susceptibility, use landslide inventory as a dependent variable to compute the predictors’ significance. Therefore, a slight change in the landslide dataset nullifies the susceptibility zones. Thus, the landslide susceptibility maps become irrelevant to mitigate slope failures. In the present study, we have used two reference period landslide dataset to execute the landslide susceptibility analysis using the frequency ratio method. The model result was validated with a landslide test dataset using the area under the curve (AUC) method. The AUC value is 0.89 and 0.91 for 2013 and 2019, respectively. The study finds that annual updating of landslide inventory is essential for susceptibility modeling for assessment of associated risks and implications of mitigation measures along the highway corridor.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"43 1","pages":"440 - 462"},"PeriodicalIF":1.6,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2021.1872857","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44672523","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 : 2020-12-09DOI: 10.1080/02723646.2020.1858556
J. Clarke, Savannah L. McGuirk, Siddharth Pandey
ABSTRACT The Hunder Dunes occur in the Shyok valley, Ladakh region, north-western India. These barchanoid and transverse dunes consist of sand reworked from the seasonally exposed beds of the river. Wind direction is strongly uni-modal from the northwest and is controlled by valley orientation. We observed small (10–20 m long, 5–10 m wide, and up to 1.5 m high) ellipsoidal mesas in the swales between dunes, composed of sand deflated from the Shyok River system. The mesas have a tiered, wedding cake appearance with concave upper surfaces. We interpret these mesas as inverted swale deposits consisting of stacked cycles of sediment. The cycles range from 40 to 50 cm in thickness and are composed of a from bottom to top, deposits of prior dunes, high energy fluvial deposits with climbing ripples, pool sediments with symmetrical wave ripples, and desiccation-cracked mud drapes over the ripples indicating final drying out of the pool. Up to four cycles of deposition were present in the mesas. The inverted swales are being both exhumed from beneath and buried underneath migrating dunes. Inverted swale deposits provide a record of historical depositional processes and biological communities active at the site.
{"title":"Inverted dune swales, Hunder, Ladakh, India","authors":"J. Clarke, Savannah L. McGuirk, Siddharth Pandey","doi":"10.1080/02723646.2020.1858556","DOIUrl":"https://doi.org/10.1080/02723646.2020.1858556","url":null,"abstract":"ABSTRACT The Hunder Dunes occur in the Shyok valley, Ladakh region, north-western India. These barchanoid and transverse dunes consist of sand reworked from the seasonally exposed beds of the river. Wind direction is strongly uni-modal from the northwest and is controlled by valley orientation. We observed small (10–20 m long, 5–10 m wide, and up to 1.5 m high) ellipsoidal mesas in the swales between dunes, composed of sand deflated from the Shyok River system. The mesas have a tiered, wedding cake appearance with concave upper surfaces. We interpret these mesas as inverted swale deposits consisting of stacked cycles of sediment. The cycles range from 40 to 50 cm in thickness and are composed of a from bottom to top, deposits of prior dunes, high energy fluvial deposits with climbing ripples, pool sediments with symmetrical wave ripples, and desiccation-cracked mud drapes over the ripples indicating final drying out of the pool. Up to four cycles of deposition were present in the mesas. The inverted swales are being both exhumed from beneath and buried underneath migrating dunes. Inverted swale deposits provide a record of historical depositional processes and biological communities active at the site.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"43 1","pages":"350 - 364"},"PeriodicalIF":1.6,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2020.1858556","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43283672","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 : 2020-12-07DOI: 10.1080/02723646.2020.1854418
Donal S. O’Leary, D. Hall, N. DiGirolamo, G. Riggs
ABSTRACT Snowmelt controls important physical and ecological processes and is widely expected to occur earlier under most climate change scenarios. The western United States (US) is dependent on seasonal snowpack for water resources and recreation, and this diverse landscape is likely to experience continued changes to snowmelt timing that will differ across the domain. In this study, we use NASA’s cloud gap-filled snow-cover maps (MOD10A1F and MYD10A1F) to detect trends in snowmelt timing for hydrologic years 2001–2018. We find that 7.04% of the snow zone (i.e., areas with 10+ years of snow throughout the study period) of the western US is experiencing statistically significant (α = 0.05) trends of earlier snowmelt, while 2.62% of the snow zone is experiencing significant trends of later snowmelt. Analyses at the ecoregion level reveal regional trends, with many southwestern ecoregions experiencing large areas of dramatically earlier snowmelt (e.g., 19.84% of the Mojave Basin and Range). Interestingly, the North Cascades and the Northern Rockies ecoregions have substantial areas of later snowmelt (5.45% and 4.99%, respectively). Our work builds upon previous estimates of snowmelt timing to identify an overall trend of earlier snowmelt while highlighting the high spatial variability in snowmelt trends throughout the western US.
{"title":"Regional trends in snowmelt timing for the western United States throughout the MODIS era","authors":"Donal S. O’Leary, D. Hall, N. DiGirolamo, G. Riggs","doi":"10.1080/02723646.2020.1854418","DOIUrl":"https://doi.org/10.1080/02723646.2020.1854418","url":null,"abstract":"ABSTRACT Snowmelt controls important physical and ecological processes and is widely expected to occur earlier under most climate change scenarios. The western United States (US) is dependent on seasonal snowpack for water resources and recreation, and this diverse landscape is likely to experience continued changes to snowmelt timing that will differ across the domain. In this study, we use NASA’s cloud gap-filled snow-cover maps (MOD10A1F and MYD10A1F) to detect trends in snowmelt timing for hydrologic years 2001–2018. We find that 7.04% of the snow zone (i.e., areas with 10+ years of snow throughout the study period) of the western US is experiencing statistically significant (α = 0.05) trends of earlier snowmelt, while 2.62% of the snow zone is experiencing significant trends of later snowmelt. Analyses at the ecoregion level reveal regional trends, with many southwestern ecoregions experiencing large areas of dramatically earlier snowmelt (e.g., 19.84% of the Mojave Basin and Range). Interestingly, the North Cascades and the Northern Rockies ecoregions have substantial areas of later snowmelt (5.45% and 4.99%, respectively). Our work builds upon previous estimates of snowmelt timing to identify an overall trend of earlier snowmelt while highlighting the high spatial variability in snowmelt trends throughout the western US.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"43 1","pages":"285 - 307"},"PeriodicalIF":1.6,"publicationDate":"2020-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2020.1854418","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46374683","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 : 2020-11-12DOI: 10.1080/02723646.2020.1847242
I. J. Breytenbach
ABSTRACT Research was undertaken to assess the influence of aspect and sub-surface depth on thermal fatigue in bedrock. Contact temperatures were recorded at depths of 0.3 m, 2.0 m and 6.0 m in boreholes drilled on three aspects of a tillite outcrop from mid-winter to mid-summer. Results showed that seasonal temperature oscillations of up to 20 ºC occurred in bedrock and that heat dissipation and build-up do not commence or cease at the same time throughout the rock mass, conceptually resulting in lateral and vertical thermal strain. Critically, thermal fatigue at depth may induce micro-cracking in bedrock, well before surface-related weathering processes or mechanisms commence.
{"title":"Seasonal bedrock temperature oscillations and inversions as a function of depth and the implications for thermal fatigue","authors":"I. J. Breytenbach","doi":"10.1080/02723646.2020.1847242","DOIUrl":"https://doi.org/10.1080/02723646.2020.1847242","url":null,"abstract":"ABSTRACT Research was undertaken to assess the influence of aspect and sub-surface depth on thermal fatigue in bedrock. Contact temperatures were recorded at depths of 0.3 m, 2.0 m and 6.0 m in boreholes drilled on three aspects of a tillite outcrop from mid-winter to mid-summer. Results showed that seasonal temperature oscillations of up to 20 ºC occurred in bedrock and that heat dissipation and build-up do not commence or cease at the same time throughout the rock mass, conceptually resulting in lateral and vertical thermal strain. Critically, thermal fatigue at depth may induce micro-cracking in bedrock, well before surface-related weathering processes or mechanisms commence.","PeriodicalId":54618,"journal":{"name":"Physical Geography","volume":"43 1","pages":"401 - 418"},"PeriodicalIF":1.6,"publicationDate":"2020-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02723646.2020.1847242","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46497151","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：