Pub Date : 2024-11-12DOI: 10.1016/j.aeolia.2024.100945
Pei Zhang , Brandon L. Edwards , Nicholas P. Webb , Andrew Trautz , John A. Gillies , Nancy P. Ziegler , Justin W. Van Zee
Sonic anemometry represents an important technological advance for aeolian studies, fostering better understanding of near-surface turbulence and improved methods for estimating shear velocity (). Here, we compare estimated from the Law of the Wall approach and from four methods that use 3-D wind vector measurements from sonic anemometers: double rotation, triple rotation, planar fit, and a newly developed approach based on invariants of the Reynolds stress tensor. Data were collected over 7.5 months at the Jornada Experimental Range in the Chihuahuan Desert, southern New Mexico, USA. We used estimates from the double rotation method as a reference for comparing the other methods because of its prevalence in the aeolian literature. On average, estimates from the other three methods are within 5.0 % of estimates from the double rotation approach. Estimates from the triple rotation approach were 2.2 % lower on average. Estimates from the planar fit method were the most similar, within 1.3 % on average. Estimates from the stress tensor approach were 4.9 % larger on average. We found significant discrepancies, ranging from −14.7 % to 13.7 %, among estimated from the Law of the Wall and the other methods. This underscores the need for careful methodology selection to ensure accurate characterization of boundary layer turbulence.
{"title":"An evaluation of different approaches for estimating shear velocity in aeolian research studies","authors":"Pei Zhang , Brandon L. Edwards , Nicholas P. Webb , Andrew Trautz , John A. Gillies , Nancy P. Ziegler , Justin W. Van Zee","doi":"10.1016/j.aeolia.2024.100945","DOIUrl":"10.1016/j.aeolia.2024.100945","url":null,"abstract":"<div><div>Sonic anemometry represents an important technological advance for aeolian studies, fostering better understanding of near-surface turbulence and improved methods for estimating shear velocity (<span><math><msub><mi>u</mi><mrow><mo>∗</mo></mrow></msub></math></span>). Here, we compare <span><math><msub><mi>u</mi><mrow><mo>∗</mo></mrow></msub></math></span> estimated from the Law of the Wall approach and from four methods that use 3-D wind vector measurements from sonic anemometers: double rotation, triple rotation, planar fit, and a newly developed approach based on invariants of the Reynolds stress tensor. Data were collected over 7.5 months at the Jornada Experimental Range in the Chihuahuan Desert, southern New Mexico, USA. We used <span><math><msub><mi>u</mi><mrow><mo>∗</mo></mrow></msub></math></span> estimates from the double rotation method as a reference for comparing the other methods because of its prevalence in the aeolian literature. On average, <span><math><msub><mi>u</mi><mrow><mo>∗</mo></mrow></msub></math></span> estimates from the other three methods are within 5.0 % of estimates from the double rotation approach. Estimates from the triple rotation approach were 2.2 % lower on average. Estimates from the planar fit method were the most similar, within 1.3 % on average. Estimates from the stress tensor approach were 4.9 % larger on average. We found significant discrepancies, ranging from −14.7 % to 13.7 %, among <span><math><msub><mi>u</mi><mrow><mo>∗</mo></mrow></msub></math></span> estimated from the Law of the Wall and the other methods. This underscores the need for careful methodology selection to ensure accurate characterization of boundary layer turbulence.</div></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"70 ","pages":"Article 100945"},"PeriodicalIF":3.1,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.aeolia.2024.100944
Lars B. Clemmensen , Aslaug C. Glad , Giulia Cossu , Vincenzo Pascucci
Aeolian sand covers a significant part of the granite peninsula Hammeren on northernmost Bornholm in the Baltic Sea. The coastline of Hammeren is rocky and apart from one relative wide and sandy pocket beach at the east coast only few, small and gravelly pocket beaches exist. The aeolian deposits form three sand covers that stretch inland from the east and northwestern facing coasts of Hammeren. The largest sand cover forms a rising sand plain that cover the granitic landscape up to 700 m inland and reaches up to 60 m above sea level. Historical sources mention aeolian sand movement around CE 1775 in the middle of the Little Ice Age, but until this study no absolute age control has been available to confirm these observations. Luminescence dating of selected sample sites indicates that aeolian sand movement took place in three episodes. The first episode was in the last part of the Younger Dryas at about 11,500 BP, the second episode was in the Danish Late Bronze Age at about 2700 BP, and the youngest episode was indeed during the Little Ice Age around 200 BP (CE 1750). These episodes with aeolian activity all fall during relatively cold climatic intervals and add support to previous studies indicating a link between cold climates an increased storminess in Northwest Europe including the southern Baltic Sea region.
{"title":"Aeolian sand cover on a granite peninsula (Hammeren, Bornholm, Baltic Sea) formed in three episodes during the past 11,600 years","authors":"Lars B. Clemmensen , Aslaug C. Glad , Giulia Cossu , Vincenzo Pascucci","doi":"10.1016/j.aeolia.2024.100944","DOIUrl":"10.1016/j.aeolia.2024.100944","url":null,"abstract":"<div><div>Aeolian sand covers a significant part of the granite peninsula Hammeren on northernmost Bornholm in the Baltic Sea. The coastline of Hammeren is rocky and apart from one relative wide and sandy pocket beach at the east coast only few, small and gravelly pocket beaches exist. The aeolian deposits form three sand covers that stretch inland from the east and northwestern facing coasts of Hammeren. The largest sand cover forms a rising sand plain that cover the granitic landscape up to 700 m inland and reaches up to 60 m above sea level. Historical sources mention aeolian sand movement around CE 1775 in the middle of the Little Ice Age, but until this study no absolute age control has been available to confirm these observations. Luminescence dating of selected sample sites indicates that aeolian sand movement took place in three episodes. The first episode was in the last part of the Younger Dryas at about 11,500 BP, the second episode was in the Danish Late Bronze Age at about 2700 BP, and the youngest episode was indeed during the Little Ice Age around 200 BP (CE 1750). These episodes with aeolian activity all fall during relatively cold climatic intervals and add support to previous studies indicating a link between cold climates an increased storminess in Northwest Europe including the southern Baltic Sea region.</div></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"70 ","pages":"Article 100944"},"PeriodicalIF":3.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1016/j.aeolia.2024.100943
Yeong Bae Seong , Kenzie L. Shandonay , Ronald I. Dorn , Brian F. Gootee , Byong Yong Yu
The Parker Dunes in western Arizona, USA represent the largest dune system in the Sonoran Desert. This study presents a simple 10Be-26Al cosmogenic burial age of 1.90 ± 0.20 Ma, obtained from well cuttings 240–270 m deep in Butler Valley, just east of the dune field. Given the large errors associated with burial dating, we can only speculate that this oldest known aeolian sediment within the Parker Dunes is roughly concurrent with the Bat Cave flood event ca. 2.1 Ma of the nearby Colorado River, as well as regional climatic aridity during the early Pleistocene. Since older dune deposits may be present at other locations in the Parker Dunes, its origin dates back to at least the early Pleistocene. The more important, broader implication rests in highlighting the underutilized potential of well cuttings as a sediment source for cosmogenic burial dating in aeolian research.
{"title":"Speculation on an early Pleistocene origin of the Parker dunes of southwest Arizona, USA","authors":"Yeong Bae Seong , Kenzie L. Shandonay , Ronald I. Dorn , Brian F. Gootee , Byong Yong Yu","doi":"10.1016/j.aeolia.2024.100943","DOIUrl":"10.1016/j.aeolia.2024.100943","url":null,"abstract":"<div><div>The Parker Dunes in western Arizona, USA represent the largest dune system in the Sonoran Desert. This study presents a simple <sup>10</sup>Be-<sup>26</sup>Al cosmogenic burial age of 1.90 ± 0.20 Ma, obtained from well cuttings 240–270 m deep in Butler Valley, just east of the dune field. Given the large errors associated with burial dating, we can only speculate that this oldest known aeolian sediment within the Parker Dunes is roughly concurrent with the Bat Cave flood event ca. 2.1 Ma of the nearby Colorado River, as well as regional climatic aridity during the early Pleistocene. Since older dune deposits may be present at other locations in the Parker Dunes, its origin dates back to at least the early Pleistocene. The more important, broader implication rests in highlighting the underutilized potential of well cuttings as a sediment source for cosmogenic burial dating in aeolian research.</div></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"70 ","pages":"Article 100943"},"PeriodicalIF":3.1,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-09-30DOI: 10.1016/j.aeolia.2024.100942
Sajjad Abbasi , Neda Hashemi , Nafiseh Khodabakhshloo , Monireh Mina , Mohammad Reza Yousefi , Andrew Turner
Dust storms are important vehicles for the erosion and translocation of geogenic material in arid and semi-arid climates but little is known about their role in transporting microplastics (MPs). In this study, local soils (n = 20) and dusts deposited from a storm (n = 41) have been sampled from a remote region of northeastern Iran (Sarakhs) and the quantities and characteristics of MPs and microrubbers (MRs) determined using established techniques. In dusts, MPs and MRs were detected in 33 and 17 cases, respectively, with respective median and maximum concentrations of 0.48 and 23.0 MP g−1 and 0.50 and 6.48 MR g−1 and depositional fluxes of up to about 12 MP m−2 h−1 and 7 MR m−2 h−1. In soils, MPs and MRs were detected in ten and eight cases, respectively, with respective median and maximum concentrations of 0.25 and 1.90 MP g−1 and 3.27 and 14.3 MR g−1. Overall, the ratio of MPs in dusts to soils relative to MRs in dusts to soils was about 20, reflecting the greater mobility of the former type of particle. This can be attributed to the ready suspension and more favourable aerodynamic properties of fibrous MPs compared with fragmented MRs. A comparison of MPs in dusts and soils suggests a preferential long-range transport of fibres with certain characteristics (e.g., long, red and constructed of polypropylene), with HYSPLIT back trajectory modelling suggesting secondary (e.g., soil) sources to the south and southwest. Dust storms are important regional transporters of atmospheric MPs and MRs whose role is predicted to increase as desertification and the demands for potable water and plastics rise.
{"title":"Transport and deposition of microplastics and microrubbers during a dust storm (Sarakhs, northeast Iran)","authors":"Sajjad Abbasi , Neda Hashemi , Nafiseh Khodabakhshloo , Monireh Mina , Mohammad Reza Yousefi , Andrew Turner","doi":"10.1016/j.aeolia.2024.100942","DOIUrl":"10.1016/j.aeolia.2024.100942","url":null,"abstract":"<div><div>Dust storms are important vehicles for the erosion and translocation of geogenic material in arid and semi-arid climates but little is known about their role in transporting microplastics (MPs). In this study, local soils (<em>n</em> = 20) and dusts deposited from a storm (<em>n</em> = 41) have been sampled from a remote region of northeastern Iran (Sarakhs) and the quantities and characteristics of MPs and microrubbers (MRs) determined using established techniques. In dusts, MPs and MRs were detected in 33 and 17 cases, respectively, with respective median and maximum concentrations of 0.48 and 23.0 MP g<sup>−1</sup> and 0.50 and 6.48 MR g<sup>−1</sup> and depositional fluxes of up to about 12 MP m<sup>−2</sup> <!-->h<sup>−1</sup> and 7 MR m<sup>−2</sup> <!-->h<sup>−1</sup>. In soils, MPs and MRs were detected in ten and eight cases, respectively, with respective median and maximum concentrations of 0.25 and 1.90 MP g<sup>−1</sup> and 3.27 and 14.3 MR g<sup>−1</sup>. Overall, the ratio of MPs in dusts to soils relative to MRs in dusts to soils was about 20, reflecting the greater mobility of the former type of particle. This can be attributed to the ready suspension and more favourable aerodynamic properties of fibrous MPs compared with fragmented MRs. A comparison of MPs in dusts and soils suggests a preferential long-range transport of fibres with certain characteristics (e.g., long, red and constructed of polypropylene), with HYSPLIT back trajectory modelling suggesting secondary (e.g., soil) sources to the south and southwest. Dust storms are important regional transporters of atmospheric MPs and MRs whose role is predicted to increase as desertification and the demands for potable water and plastics rise.</div></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"70 ","pages":"Article 100942"},"PeriodicalIF":3.1,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-09-21DOI: 10.1016/j.aeolia.2024.100941
Abby L. Mangum , Gregory T. Carling , Barry R. Bickmore , Nicholas Webb , DeTiare L. Leifi , Janice Brahney , Diego P. Fernandez , Kevin A. Rey , Stephen T. Nelson , Landon Burgener , Joshua J. LeMonte , Alyssa N. Thompson , Beth A. Newingham , Michael C. Duniway , Zachary T. Aanderud
Dust events originate from multiple sources in arid and semi-arid regions, making it difficult to quantify source contributions. Dust geochemical/mineralogical composition, if the sources are sufficiently distinct, can be used to quantify the contributions from different sources. To test the viability of using geochemical and mineralogical measurements to separate dust-emitting sites, we used dust samples collected between 2018 and 2020 from ten National Wind Erosion Research Network (NWERN) sites that are representative of western United States (US) dust sources. Dust composition varied seasonally at many of the sites, but within-site variability was smaller than across-site variability, indicating that the geochemical signatures are robust over time. It was not possible to separate all the sites using commonly applied principal component analysis (PCA) and cluster analysis because of overlap in dust geochemistry. However, a linear discriminant analysis (LDA) successfully separated all sites based on their geochemistry, suggesting that LDA may prove useful for separating dust sources that cannot be separated using PCA or other methods. Further, an LDA based on mineralogical data separated most sites using only a limited number of mineral phases that were readily explained by the local geologic setting. Taken together, the geochemical and mineralogical measurements generated distinct signatures of dust emissions across NWERN sites. If expanded to include a broader range of sites across the western US, a library of geochemical and mineralogical data may serve as a basis to track and quantify dust contributions from these sources.
{"title":"Characterizing variability in geochemistry and mineralogy of western US dust sources","authors":"Abby L. Mangum , Gregory T. Carling , Barry R. Bickmore , Nicholas Webb , DeTiare L. Leifi , Janice Brahney , Diego P. Fernandez , Kevin A. Rey , Stephen T. Nelson , Landon Burgener , Joshua J. LeMonte , Alyssa N. Thompson , Beth A. Newingham , Michael C. Duniway , Zachary T. Aanderud","doi":"10.1016/j.aeolia.2024.100941","DOIUrl":"10.1016/j.aeolia.2024.100941","url":null,"abstract":"<div><div>Dust events originate from multiple sources in arid and semi-arid regions, making it difficult to quantify source contributions. Dust geochemical/mineralogical composition, if the sources are sufficiently distinct, can be used to quantify the contributions from different sources. To test the viability of using geochemical and mineralogical measurements to separate dust-emitting sites, we used dust samples collected between 2018 and 2020 from ten National Wind Erosion Research Network (NWERN) sites that are representative of western United States (US) dust sources. Dust composition varied seasonally at many of the sites, but within-site variability was smaller than across-site variability, indicating that the geochemical signatures are robust over time. It was not possible to separate all the sites using commonly applied principal component analysis (PCA) and cluster analysis because of overlap in dust geochemistry. However, a linear discriminant analysis (LDA) successfully separated all sites based on their geochemistry, suggesting that LDA may prove useful for separating dust sources that cannot be separated using PCA or other methods. Further, an LDA based on mineralogical data separated most sites using only a limited number of mineral phases that were readily explained by the local geologic setting. Taken together, the geochemical and mineralogical measurements generated distinct signatures of dust emissions across NWERN sites. If expanded to include a broader range of sites across the western US, a library of geochemical and mineralogical data may serve as a basis to track and quantify dust contributions from these sources.</div></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"70 ","pages":"Article 100941"},"PeriodicalIF":3.1,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-09-21DOI: 10.1016/j.aeolia.2024.100940
Hongji Zhou , Fanmin Mei , Chuan Lin , Mengjie Pu , Aiguo Xi , Jinguang Chen , Jin Su , Zhibao Dong
The evolution of saltating tracks driven by strong wind remains unknown due to the low accuracy or recall rates of saltating particle tracking algorithms (SPTs). Manual identification of saltating tracks becomes a primary bottleneck because of low efficiency, restricting the development of new SPTs with high accuracy. Herein, we proposed an optimized tree model for automatically identifying saltating tracks in the high-speed video under strong wind through establishing the dataset with multiple statistical quantities of instant saltating velocity (MSQV) and the workflow embracing the Tree-structured Parzen Estimator (TPE). The optimized Categorical Boosting model by the D3 dataset (CatBoost-D3) could be considered the best classifier among the tree models, owning the higher accuracy (0.9352), precision (0.9348), recall (0.9352), F1-score (0.9350) and area under an receiver operating characteristics curve (AUC, 0.9730), and lower time cost. The best performances were associated with the ensemble effect of critical and secondary features, distinct from the previous finding which revealed only the effect of critical features on enhancing AUC value. Additionally, one observed that the present model was comparable to other optimized tree model by the dataset with double-class and outperformed the other tree model by the dataset with multi-class. The present work offers a new avenue for identifying hop trajectories and tracking sand particle flow via machine learning in the future, and a new channel for reunderstanding the relationship between midair collision and saltation under strong wind through automatic identification of saltating tracks.
{"title":"Automatic identification of saltating tracks driven by strong wind in high-speed video using multiple statistical quantities of instant particle velocity","authors":"Hongji Zhou , Fanmin Mei , Chuan Lin , Mengjie Pu , Aiguo Xi , Jinguang Chen , Jin Su , Zhibao Dong","doi":"10.1016/j.aeolia.2024.100940","DOIUrl":"10.1016/j.aeolia.2024.100940","url":null,"abstract":"<div><p>The evolution of saltating tracks driven by strong wind remains unknown due to the low accuracy or recall rates of saltating particle tracking algorithms (SPTs). Manual identification of saltating tracks becomes a primary bottleneck because of low efficiency, restricting the development of new SPTs with high accuracy. Herein, we proposed an optimized tree model for automatically identifying saltating tracks in the high-speed video under strong wind through establishing the dataset with multiple statistical quantities of instant saltating velocity (<em>MSQV</em>) and the workflow embracing the Tree-structured Parzen Estimator (TPE). The optimized Categorical Boosting model by the D3 dataset (CatBoost-D3) could be considered the best classifier among the tree models, owning the higher accuracy (0.9352), precision (0.9348), recall (0.9352), F1-score (0.9350) and area under an receiver operating characteristics curve (AUC, 0.9730), and lower time cost. The best performances were associated with the ensemble effect of critical and secondary features, distinct from the previous finding which revealed only the effect of critical features on enhancing AUC value. Additionally, one observed that the present model was comparable to other optimized tree model by the dataset with double-class and outperformed the other tree model by the dataset with multi-class. The present work offers a new avenue for identifying hop trajectories and tracking sand particle flow via machine learning in the future, and a new channel for reunderstanding the relationship between midair collision and saltation under strong wind through automatic identification of saltating tracks.</p></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"70 ","pages":"Article 100940"},"PeriodicalIF":3.1,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-07-22DOI: 10.1016/j.aeolia.2024.100939
Ning Jiang, Hong Cheng
The grain size characteristics of aeolian sediments are the combined result of sand sources, regional airflow regimes, dune morphology, etc., and are essential for understanding the formation and evolution of barchan dunes. Based on field investigations and laboratory experimental data, in this paper, we explored differences in the grain size characteristics of the surface sediments of barchan dunes at the southeastern edge of the Taklimakan Desert (TKLM-SE), the western (QB-W) and southern parts of the Qaidam Basin Desert (QB-S), the sand belt connecting the Badain Jaran Desert and the Tengger Desert (BT-B), and their responses to sand sources, dune morphology, and wind regimes. The main results were as follows: (i) The mean grian size distribution patterns of the windward slope toe to the leeward slope toe through the dune crest/ridge varied with different transects of the barchan dunes and different deserts, showing four types including gradually fining (GF), gradually coarsening (GC), coarsening followed by fining (CF), and fining followed by coarsening (FC). The patterns were GF and CF in the TKLM-SE; GF, GC, and FC in the BT-B; GF, GC, and CF in the QB-W; and GF in the QB-S. (ii) The interdune sediments provided the source material for the formation and development of barchan dunes and their grain size varied in different deserts. The interdune sediments were composed of gravel and very fine sand in the TKLM-SE, while they were composed of medium and fine sand in the QB-W, QB-S, and BT-B. (iii) The windward side of the barchans varied with different wind directions, and dune height affected dune surface airflow velocity and direction, changing the pattern of grain size distribution on the dune surface. The wind regime over a ten-day or half-month scale could explain the variance in the grain size distribution patterns better than that on an annual scale. (iv) Grain size characteristics of dune surface sands changed with dune shape due to changes in the surface airflow velocity and direction and the sediment-carrying capacity of the airflow. With an increasing ratio of dune height to dune width, the grain size of the dune crest sands became coarser. These results help advance our understanding of the grain size characteristics of barchan dunes and regional variabilities in their patterns.
{"title":"Regional differences in the grain size characteristics of surface sediments from typical barchan dunes in arid zones","authors":"Ning Jiang, Hong Cheng","doi":"10.1016/j.aeolia.2024.100939","DOIUrl":"10.1016/j.aeolia.2024.100939","url":null,"abstract":"<div><p>The grain size characteristics of aeolian sediments are the combined result of sand sources, regional airflow regimes, dune morphology, etc., and are essential for understanding the formation and evolution of barchan dunes. Based on field investigations and laboratory experimental data, in this paper, we explored differences in the grain size characteristics of the surface sediments of barchan dunes at the southeastern edge of the Taklimakan Desert (TKLM-SE), the western (QB-W) and southern parts of the Qaidam Basin Desert (QB-S), the sand belt connecting the Badain Jaran Desert and the Tengger Desert (BT-B), and their responses to sand sources, dune morphology, and wind regimes. The main results were as follows: (i) The mean grian size distribution patterns of the windward slope toe to the leeward slope toe through the dune crest/ridge varied with different transects of the barchan dunes and different deserts, showing four types including gradually fining (GF), gradually coarsening (GC), coarsening followed by fining (CF), and fining followed by coarsening (FC). The patterns were GF and CF in the TKLM-SE; GF, GC, and FC in the BT-B; GF, GC, and CF in the QB-W; and GF in the QB-S. (ii) The interdune sediments provided the source material for the formation and development of barchan dunes and their grain size varied in different deserts. The interdune sediments were composed of gravel and very fine sand in the TKLM-SE, while they were composed of medium and fine sand in the QB-W, QB-S, and BT-B. (iii) The windward side of the barchans varied with different wind directions, and dune height affected dune surface airflow velocity and direction, changing the pattern of grain size distribution on the dune surface. The wind regime over a ten-day or half-month scale could explain the variance in the grain size distribution patterns better than that on an annual scale. (iv) Grain size characteristics of dune surface sands changed with dune shape due to changes in the surface airflow velocity and direction and the sediment-carrying capacity of the airflow. With an increasing ratio of dune height to dune width, the grain size of the dune crest sands became coarser. These results help advance our understanding of the grain size characteristics of barchan dunes and regional variabilities in their patterns.</p></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"70 ","pages":"Article 100939"},"PeriodicalIF":3.1,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141960374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-07-06DOI: 10.1016/j.aeolia.2024.100938
Hojat Emami , Mahsa Memarzadeh , Fateme Naghizade Asl
Dust particles are considered as a very important way of soil contamination by heavy metals. Therefore, this study was conducted to evaluate the concentration of heavy metals and their health risk in windborne sediments. For this purpose, sediment traps were installed in five dominant wind directions including north, northeast, northwest, west, and southwest, and center of Tabas city (Iran) to collect the suspended sediments in the air. Sediment sampling was conducted monthly from January to December 2021. The concentrations of heavy metals were measured using atomic adsorption method followed by extraction by aqua regia, and the carcinogenic and non-carcinogenic health risks of heavy metals for children and adults were evaluated during different months of the year. According to the results, the maximum and minimum amounts of windborne sediments found in northwest (85.66 gm−2) and west (29.3 gm−2), respectively. Monthly variations in windborne sediments discharge also revealed that the maximum amounts of windborne sediments occurred in September and November 2021 from northeast (125 and 117 mgkg−1, respectively). The maximum concentrations of cadmium (0.82 mg/kg) were found in the west of Tabas, while those of lead (192.72 mg/kg), and nickel (227.34 mg/kg) were obtained in the city center. In addition, the highest carcinogenic and non-carcinogenic risks belonged to nickel and the lowest risks were obtained for lead. Also, the carcinogenic risk of cadmium was higher than lead but lower than nickel. In general, the carcinogenic and non-carcinogenic risks of the studied heavy metals were low (less than 1).
{"title":"Carcinogenic and non-carcinogenic health risks of heavy metals in windborne sediments from a residential area (Case study: Tabas, Iran)","authors":"Hojat Emami , Mahsa Memarzadeh , Fateme Naghizade Asl","doi":"10.1016/j.aeolia.2024.100938","DOIUrl":"https://doi.org/10.1016/j.aeolia.2024.100938","url":null,"abstract":"<div><p>Dust particles are considered as a very important way of soil contamination by heavy metals. Therefore, this study was conducted to evaluate the concentration of heavy metals and their health risk in windborne sediments. For this purpose, sediment traps were installed in five dominant wind directions including north, northeast, northwest, west, and southwest, and center of Tabas city (Iran) to collect the suspended sediments in the air. Sediment sampling was conducted monthly from January to December 2021. The concentrations of heavy metals were measured using atomic adsorption method followed by extraction by aqua regia, and the carcinogenic and non-carcinogenic health risks of heavy metals for children and adults were evaluated during different months of the year. According to the results, the maximum and minimum amounts of windborne sediments found in northwest (85.66 gm<sup>−2</sup>) and west (29.3 gm<sup>−2</sup>), respectively. Monthly variations in windborne sediments discharge also revealed that the maximum amounts of windborne sediments occurred in September and November 2021 from northeast (125 and 117 mgkg<sup>−1</sup>, respectively). The maximum concentrations of cadmium (0.82 mg/kg) were found in the west of Tabas, while those of lead (192.72 mg/kg), and nickel (227.34 mg/kg) were obtained in the city center. In addition, the highest carcinogenic and non-carcinogenic risks belonged to nickel and the lowest risks were obtained for lead. Also, the carcinogenic risk of cadmium was higher than lead but lower than nickel. In general, the carcinogenic and non-carcinogenic risks of the studied heavy metals were low (less than 1).</p></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"70 ","pages":"Article 100938"},"PeriodicalIF":3.1,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141595120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-05-20DOI: 10.1016/j.aeolia.2024.100930
M.C. Robinson, K. Ardon-Dryer
Dust events are caused by strong winds that lift dust particles into the air. Due to surrounding deserts and agriculture, West Texas experiences many dust events. This study examines dust events that occurred between 2000 and 2020 across four locations: Amarillo, Lubbock, Midland, and El Paso. A total of 1,834 dust events were identified across the four locations with an average of 22 dust events annually. 227 dust events were observed in Amarillo, 609 in Lubbock, 545 in Midland, and 453 dust events were observed in El Paso. A slight increasing trend of dust events over time was observed for Amarillo, Lubbock, and Midland while El Paso showed a decreasing trend. Most dust events occurred during the spring to early summer months and they lasted an hour or less. Many dust events occurred during times of drought and periods of La Niña. Separation of the dust events based on the meteorological disturbance that caused them (convective vs. synoptic) showed that synoptic disturbances contribute to >60 % of the dust events, while convective disturbances were responsible for most of the remaining. Synoptic disturbances were predominately in spring while convective disturbances were common in the early summer months. A comparison of meteorological parameters measured during each disturbance shows that synoptic dust events were associated with lower temperatures, dew point, and relative humidity, but with higher wind speeds and gusts.
{"title":"Characterization of 21 years of dust events across four West Texas regions","authors":"M.C. Robinson, K. Ardon-Dryer","doi":"10.1016/j.aeolia.2024.100930","DOIUrl":"https://doi.org/10.1016/j.aeolia.2024.100930","url":null,"abstract":"<div><p>Dust events are caused by strong winds that lift dust particles into the air. Due to surrounding deserts and agriculture, West Texas experiences many dust events. This study examines dust events that occurred between 2000 and 2020 across four locations: Amarillo, Lubbock, Midland, and El Paso. A total of 1,834 dust events were identified across the four locations with an average of 22 dust events annually. 227 dust events were observed in Amarillo, 609 in Lubbock, 545 in Midland, and 453 dust events were observed in El Paso. A slight increasing trend of dust events over time was observed for Amarillo, Lubbock, and Midland while El Paso showed a decreasing trend. Most dust events occurred during the spring to early summer months and they lasted an hour or less. Many dust events occurred during times of drought and periods of La Niña. Separation of the dust events based on the meteorological disturbance that caused them (convective vs. synoptic) showed that synoptic disturbances contribute to >60 % of the dust events, while convective disturbances were responsible for most of the remaining. Synoptic disturbances were predominately in spring while convective disturbances were common in the early summer months. A comparison of meteorological parameters measured during each disturbance shows that synoptic dust events were associated with lower temperatures, dew point, and relative humidity, but with higher wind speeds and gusts.</p></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"67 ","pages":"Article 100930"},"PeriodicalIF":3.3,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1875963724000417/pdfft?md5=b56fd224fd238b77ad4aefbe25b1722b&pid=1-s2.0-S1875963724000417-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141067923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-18DOI: 10.1016/j.aeolia.2024.100920
Manuel Herzog , Alexander Schmitt , Olaf Bubenzer
The evolution of large star dunes, because of their remote location, size and surface complexity, is barely recorded and understood. This lack of understanding applies to surface and subsurface features alike. In order to detect the transformation, the detailed subsurface stratigraphy and the relative chronology of large star dunes, we used ground penetrating radar (GPR) on all major arms of a complex star dune of Erg Chebbi, south-eastern Morocco. We used a 350 MHz digital antenna from Geophysical Survey Systems, Inc (GSSI), reaching a depth of 12.5 m to identify main radar facies associated with former downwind dune flanks describing the depositional history. Our results enable the determination of former dune crest positions, their potential past movement and in consequence the construction of the paleo-dune topography. In accordance with simulated historical wind data, we found a potential sediment deficit on the south-eastern side of the dune. This also correlates with surface data describing an oblique form of the star dune and the spatial distribution frequency of its major arms. Our detailed recordings show, for the first time, the complex internal composition of all arms of one large star dune and surface sensitive form-flow interactions. Our results allow the discrimination of deposition phases and therefore, we have constructed a relative chronology as a basis for future sampling and the reconstruction of star dune evolution in general.
{"title":"Reconstructing star dune dynamics using ground penetrating radar – How movement shapes complex surface structures","authors":"Manuel Herzog , Alexander Schmitt , Olaf Bubenzer","doi":"10.1016/j.aeolia.2024.100920","DOIUrl":"https://doi.org/10.1016/j.aeolia.2024.100920","url":null,"abstract":"<div><p>The evolution of large star dunes, because of their remote location, size and surface complexity, is barely recorded and understood. This lack of understanding applies to surface and subsurface features alike. In order to detect the transformation, the detailed subsurface stratigraphy and the relative chronology of large star dunes, we used ground penetrating radar (GPR) on all major arms of a complex star dune of Erg Chebbi, south-eastern Morocco. We used a 350 MHz digital antenna from Geophysical Survey Systems, Inc (GSSI), reaching a depth of 12.5 m to identify main radar facies associated with former downwind dune flanks describing the depositional history. Our results enable the determination of former dune crest positions, their potential past movement and in consequence the construction of the paleo-dune topography. In accordance with simulated historical wind data, we found a potential sediment deficit on the south-eastern side of the dune. This also correlates with surface data describing an oblique form of the star dune and the spatial distribution frequency of its major arms. Our detailed recordings show, for the first time, the complex internal composition of all arms of one large star dune and surface sensitive form-flow interactions. Our results allow the discrimination of deposition phases and therefore, we have constructed a relative chronology as a basis for future sampling and the reconstruction of star dune evolution in general.</p></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":"67 ","pages":"Article 100920"},"PeriodicalIF":3.3,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1875963724000314/pdfft?md5=9c20c075b4d75bb64e8ddd31f3c4c456&pid=1-s2.0-S1875963724000314-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141067922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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