Khalid Ziadi, A. Barakat, Abdenbi El Aloui, Mustapha Ouayah, M. Namous
Morocco watersheds, which provided many ecosystem services necessary for the socio-economic life of rural communities, are experiencing significant change and environmental problems. Therefore, examining potential soil erosion considered a major problem in the Moroccan highlands is very important to prioritize high erosion severity areas. Keeping in view of the above aspects, the present study aimed to evaluate and map areas at risk of water erosion in the upstream Tassaoute watershed (central High Atlas, Morocco), using the Priority Action Program/Regional Activity Center (PAP/RAC) method associated with Geographic Information Systems (GIS) and remote sensing. The PAP/RAC approach consisted of integrating the natural factors that influence water erosion, namely slope, lithology, vegetation cover and land use. This method provided an accurate cartographic product that reflects the reality of the state of soil degradation and the qualitative assessment of erosion. The generated erosion risk map of the study area showed that the phenomenon of erosion threatens this basin, especially in the middle and downstream, such that 40% of the basin surface has significant erosion and the high and very high degree of erosion represented 27% of the total surface of the study area. These results therefore demonstrated the PAP/CAR model reliability in assessing and mapping of water erosion risks in the upstream Tassaoute basin.
{"title":"Modelling and mapping of soil erosion risk based on GIS and PAP/RAC guidelines in the watershed of Tassaoute (Central High-Atlas, Morocco)","authors":"Khalid Ziadi, A. Barakat, Abdenbi El Aloui, Mustapha Ouayah, M. Namous","doi":"10.12775/bgeo-2023-0005","DOIUrl":"https://doi.org/10.12775/bgeo-2023-0005","url":null,"abstract":"Morocco watersheds, which provided many ecosystem services necessary for the socio-economic life of rural communities, are experiencing significant change and environmental problems. Therefore, examining potential soil erosion considered a major problem in the Moroccan highlands is very important to prioritize high erosion severity areas. Keeping in view of the above aspects, the present study aimed to evaluate and map areas at risk of water erosion in the upstream Tassaoute watershed (central High Atlas, Morocco), using the Priority Action Program/Regional Activity Center (PAP/RAC) method associated with Geographic Information Systems (GIS) and remote sensing. The PAP/RAC approach consisted of integrating the natural factors that influence water erosion, namely slope, lithology, vegetation cover and land use. This method provided an accurate cartographic product that reflects the reality of the state of soil degradation and the qualitative assessment of erosion. The generated erosion risk map of the study area showed that the phenomenon of erosion threatens this basin, especially in the middle and downstream, such that 40% of the basin surface has significant erosion and the high and very high degree of erosion represented 27% of the total surface of the study area. These results therefore demonstrated the PAP/CAR model reliability in assessing and mapping of water erosion risks in the upstream Tassaoute basin.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91369507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this study is to attempt a creative mapping of areas at risk of floods in Amman, using the Analytic Hierarchy Process (AHP) Method and GIS Modeling. The method (AHP) involves a weighting of a number of factors adopted by comparison. The main factors considered in this study were Elevation, Slope, Rainfall Intensity, Runoff, Land Use/Land Cover, Flow Accumulation, and SPI; these were reclassified and weighted to map the levels of flood hazards in the study area. Each factor/criteria was weighted and assigned a rank or score by using the Pairwise Comparison method to enable researchers to make a decision about the severity of the flood. The results show that about 28.2 % of the study area has a high to very high risk of flooding and that flooding can be very strong in the northwestern regions with high population density, while the risk becomes low in the eastern, southeastern, and western arid and semi-arid regions with low population density.
{"title":"Detection of flood-hazard-prone zones using GIS modeling and AHP method in urban areas: the case of Amman Governorate","authors":"Noah Al-Sababhah","doi":"10.12775/bgeo-2023-0001","DOIUrl":"https://doi.org/10.12775/bgeo-2023-0001","url":null,"abstract":"The aim of this study is to attempt a creative mapping of areas at risk of floods in Amman, using the Analytic Hierarchy Process (AHP) Method and GIS Modeling. The method (AHP) involves a weighting of a number of factors adopted by comparison. The main factors considered in this study were Elevation, Slope, Rainfall Intensity, Runoff, Land Use/Land Cover, Flow Accumulation, and SPI; these were reclassified and weighted to map the levels of flood hazards in the study area. Each factor/criteria was weighted and assigned a rank or score by using the Pairwise Comparison method to enable researchers to make a decision about the severity of the flood. The results show that about 28.2 % of the study area has a high to very high risk of flooding and that flooding can be very strong in the northwestern regions with high population density, while the risk becomes low in the eastern, southeastern, and western arid and semi-arid regions with low population density.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80158655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gain of heat and temperature in the shallow subsurface over the last decades/century has been impacted by the industrial period climatic surface air temperature (SAT) increase. Detailed study of the available temperature-depth data based on 43 wells with single and repeated temperature logs done by the first author has been combined with data base information (Jessop et al 2005) to create temperature maps at depth. Based on these 43 logs it is shown that the heat flux increases with depth in most cases for the available depth data range from surface to some 200m. Model of heat flow versus depth based on the surface air temperature changes through the industrial epoque climatic warming explains the data. Spatial and depth distribution of available temperature and heat gain through the provinces of the Western Canadian Sedimentary Basin WCSB shows that drilling closer to surface is more economic than deeper to 50-100m.
近几十年/一个世纪以来，浅层地下的热量和温度的增加受到了工业时期气候地表气温(SAT)升高的影响。第一作者对43口井的温度-深度数据进行了详细研究，并将其与数据库信息(Jessop et al 2005)相结合，创建了深度温度图。根据这43条测井曲线，在地表至约200m的可用深度数据范围内，热通量在大多数情况下随深度增加而增加。基于工业时代气候变暖期间地表气温变化的热流随深度变化模式解释了这些数据。加拿大西部沉积盆地WCSB各省可用温度和热增益的空间和深度分布表明，靠近地表的钻井比深度50-100米的钻井更经济。
{"title":"Shallow geothermal heat in Western Canada: climatic warming impact changes with time– depth","authors":"J. Majorowicz, J. Šafanda","doi":"10.12775/bgeo-2023-0003","DOIUrl":"https://doi.org/10.12775/bgeo-2023-0003","url":null,"abstract":"Gain of heat and temperature in the shallow subsurface over the last decades/century has been impacted by the industrial period climatic surface air temperature (SAT) increase. Detailed study of the available temperature-depth data based on 43 wells with single and repeated temperature logs done by the first author has been combined with data base information (Jessop et al 2005) to create temperature maps at depth. Based on these 43 logs it is shown that the heat flux increases with depth in most cases for the available depth data range from surface to some 200m. Model of heat flow versus depth based on the surface air temperature changes through the industrial epoque climatic warming explains the data. Spatial and depth distribution of available temperature and heat gain through the provinces of the Western Canadian Sedimentary Basin WCSB shows that drilling closer to surface is more economic than deeper to 50-100m.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90661554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There are about 6,800 lakes in the Polish Lowlands. They are a potential place for rest and recreation not only for the local population, but also for those coming from other regions of Poland and foreign guests. The work was based on the analysis of water temperature data in lakes in the years 1961–2020. The highest surface water temperatures in lakes occurred most often at the turn of the last decade of July and the fi rst decade of August, reaching values above 2 °C in most lakes. In the daily cycle, the highest water temperatures in the surface water layer (up to 1.5 m deep) were recorded mostly between 14:00 and 17:00 (13:00–16:00 GMT). The beginning of the bathing season on lakes in Poland usually falls between May 20 and 25, while the end is in the second half of September, reaching an average of about 69 days, characterized by a positive trend in its duration. According to the Chief Sanitary Inspectorate in Poland, in 2020 there were 602 active bathing areas, most of which were organized on lakes.
{"title":"Natural conditions for the development of lake tourism in Poland","authors":"R. Skowron","doi":"10.12775/bgeo-2023-0002","DOIUrl":"https://doi.org/10.12775/bgeo-2023-0002","url":null,"abstract":"There are about 6,800 lakes in the Polish Lowlands. They are a potential place for rest and recreation not only for the local population, but also for those coming from other regions of Poland and foreign guests. The work was based on the analysis of water temperature data in lakes in the years 1961–2020. The highest surface water temperatures in lakes occurred most often at the turn of the last decade of July and the fi rst decade of August, reaching values above 2 °C in most lakes. In the daily cycle, the highest water temperatures in the surface water layer (up to 1.5 m deep) were recorded mostly between 14:00 and 17:00 (13:00–16:00 GMT). The beginning of the bathing season on lakes in Poland usually falls between May 20 and 25, while the end is in the second half of September, reaching an average of about 69 days, characterized by a positive trend in its duration. According to the Chief Sanitary Inspectorate in Poland, in 2020 there were 602 active bathing areas, most of which were organized on lakes.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79641221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study aims to identify prime factors of active and continuous riverbank erosion. Field visits were conducted from 2015 to 2019. To fulfil the objective of the study, 21 study units prone to bank erosion were selected along the banks of Ganga-Bhagirathi at Jangipur sub-division. Remote sensing and geographic information system were used to measure the area under erosion and deposition from the 1985 to 2015 at five-year intervals. Bank height, bank angle, length of fracture from bank line, river velocity, and channel depth were measured for each study unit using different instruments like cup-type water current meter, clinometers, and measuring tape. Soil samples were collected for textural analysis. Factor analysis was performed to find out prime responsible factors for active riverbank erosion. The result of the study shows that bank height, bank angle, channel width, and fracture length together comprise the first component, which explains 29.48 percent of variance. Riverbank erosion happens due to physical and manmade factors in the lower plain area of the Ganga-Bhagirathi River.
{"title":"Identification of prime factors of active river bank erosion in the lower course of Ganga Bhagirathi River: a study","authors":"D. Ghosh","doi":"10.12775/bgeo-2022-0011","DOIUrl":"https://doi.org/10.12775/bgeo-2022-0011","url":null,"abstract":"The present study aims to identify prime factors of active and continuous riverbank erosion. Field visits were conducted from 2015 to 2019. To fulfil the objective of the study, 21 study units prone to bank erosion were selected along the banks of Ganga-Bhagirathi at Jangipur sub-division. Remote sensing and geographic information system were used to measure the area under erosion and deposition from the 1985 to 2015 at five-year intervals. Bank height, bank angle, length of fracture from bank line, river velocity, and channel depth were measured for each study unit using different instruments like cup-type water current meter, clinometers, and measuring tape. Soil samples were collected for textural analysis. Factor analysis was performed to find out prime responsible factors for active riverbank erosion. The result of the study shows that bank height, bank angle, channel width, and fracture length together comprise the first component, which explains 29.48 percent of variance. Riverbank erosion happens due to physical and manmade factors in the lower plain area of the Ganga-Bhagirathi River.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86771431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Atmospheric pressure, the meteorological parameter describing pressure conditions in an area, was analysed based on daily values. The mean atmospheric pressure in the Bydgoszcz area in the examined multi-annual period from 1971 to 2010 was 1006.4 hPa. Comparison of the mean value of atmospheric pressure calculated for the periods from 1971 to 1990 and from 1991 to 2010 revealed bi-directional differences between them. The atmospheric pressure curve featured high year to-year variability in the examined 40-year period. In Bydgoszcz, there was a statistically insignificant downward trend in mean annual atmospheric pressure (0.2 hPa/10 years) from 1971 to 2010.
{"title":"Temporal variations in the atmospheric pressure curve in the Bydgoszcz area","authors":"E. Łaszyca","doi":"10.12775/bgeo-2022-0010","DOIUrl":"https://doi.org/10.12775/bgeo-2022-0010","url":null,"abstract":"Atmospheric pressure, the meteorological parameter describing pressure conditions in an area, was analysed based on daily values. The mean atmospheric pressure in the Bydgoszcz area in the examined multi-annual period from 1971 to 2010 was 1006.4 hPa. Comparison of the mean value of atmospheric pressure calculated for the periods from 1971 to 1990 and from 1991 to 2010 revealed bi-directional differences between them. The atmospheric pressure curve featured high year to-year variability in the examined 40-year period. In Bydgoszcz, there was a statistically insignificant downward trend in mean annual atmospheric pressure (0.2 hPa/10 years) from 1971 to 2010.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73336409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Slaking is a rapid wetting of soil aggregates that affects their stability in the face of the effects of water. The aggregate’s stability has an indirect influence on soil functioning through its minimising of soil erosion. Testing slaking is very simple, does not need additional complicated equipment and could be done for any point. Testing was performed for natural air-dry aggregates (7–10 mm) sampled from the arable layers of four different types of soils within a young hummocky moraine landscape: Eutric Regosol (Protocalcic), Haplic Luvisol (Protocalcic), Albic Luvisol, Mollic Gleysol. The soil tests were performed on a soil-erosive catena located in Chełmno Lake District (Northern Poland) from the tops of hummocks and from the shoulder to bottom part of depressions. The test results demonstrated a significant decrease in aggregate stability from Mollic Gleysol to Eutric Regosols (Protocalcic) – that is, from colluvial soils at depressions to completely eroded hummock-top soils. However, 75% of all aggregates in Eutric Regosols were unstable when time of aggregate destruction was less than 300 sec. Oppositely to Eutric Regosols laying on hummock tops, 70% of aggregates of Mollic Gleysols in depressions were water stable. The mean time for aggregate destruction for each soil from hummock-top to depression was 209 sec. for Eutric Regosol, 375 sec. for Haplic Luvisol, 616 sec. for Albic Luvisol and 772 sec. for Mollic Gleysol. The main soil properties that affected the time of aggregate destruction are clay content (very strong negative correlation; r=–0.72); soil organic carbon content (strong positive correlation; r=0.69), and content of secondary carbonates (strong negative correlation; r=–0.69).
{"title":"Time of aggregate destruction as a parameter of soil water stability within an agricultural hummocky moraine landscape in northern Poland","authors":"Hanna Radziuk, M. Świtoniak","doi":"10.12775/bgeo-2022-0009","DOIUrl":"https://doi.org/10.12775/bgeo-2022-0009","url":null,"abstract":"Slaking is a rapid wetting of soil aggregates that affects their stability in the face of the effects of water. The aggregate’s stability has an indirect influence on soil functioning through its minimising of soil erosion. Testing slaking is very simple, does not need additional complicated equipment and could be done for any point. Testing was performed for natural air-dry aggregates (7–10 mm) sampled from the arable layers of four different types of soils within a young hummocky moraine landscape: Eutric Regosol (Protocalcic), Haplic Luvisol (Protocalcic), Albic Luvisol, Mollic Gleysol. The soil tests were performed on a soil-erosive catena located in Chełmno Lake District (Northern Poland) from the tops of hummocks and from the shoulder to bottom part of depressions. The test results demonstrated a significant decrease in aggregate stability from Mollic Gleysol to Eutric Regosols (Protocalcic) – that is, from colluvial soils at depressions to completely eroded hummock-top soils. However, 75% of all aggregates in Eutric Regosols were unstable when time of aggregate destruction was less than 300 sec. Oppositely to Eutric Regosols laying on hummock tops, 70% of aggregates of Mollic Gleysols in depressions were water stable. The mean time for aggregate destruction for each soil from hummock-top to depression was 209 sec. for Eutric Regosol, 375 sec. for Haplic Luvisol, 616 sec. for Albic Luvisol and 772 sec. for Mollic Gleysol. The main soil properties that affected the time of aggregate destruction are clay content (very strong negative correlation; r=–0.72); soil organic carbon content (strong positive correlation; r=0.69), and content of secondary carbonates (strong negative correlation; r=–0.69).","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86032458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study analysed the historical (1961–90) and projected rainfall variability for the rainy season expected in the near future (2021–50) at selected locations within the Komadugu-Yobe and Sokoto-Rima River Basins in the Sudano-Sahelian zone of northern Nigeria. Three models were utilised, and analyses were based on Representative Concentration Pathway (RCP) 8.5. Projected changes in mean, level of variability and distribution of rainfall were analysed using the Relative Percentage Change Method and the Precipitation Concentration Index (PCI), while the performance of the models was evaluated using the Nash–Sutcliffe Efficiency (NSE) index. The results show that changes in mean rainfall will be predominantly negative, with a minimum and maximum level of change of ˗1.02 per cent at Nguru, and ˗70.4 per cent at Jos, based on the IPSL-CM5A and HadGEM2-ES models, respectively. The rainy season of the baseline period varied between low and moderate variability, while the near future ranges between low and high levels of variability. The validation indicates acceptable levels of performance, with most values ranging between 0.0 and 1.0. The PCI for the near future suggests that the rainy season will be mainly characterised by uniform and near-uniform rainfall distribution. Hence, the projected negative changes and high variability of rainfall at some locations call for the development of an Adaptive Benefit Mechanism that will minimise future natural resource conflicts.
{"title":"Rainfall dynamics in the Sudano-Sahelian zone of Nigeria under RCP 8.5","authors":"O. Adegun, S. Odunuga","doi":"10.12775/bgeo-2022-0007","DOIUrl":"https://doi.org/10.12775/bgeo-2022-0007","url":null,"abstract":"The study analysed the historical (1961–90) and projected rainfall variability for the rainy season expected in the near future (2021–50) at selected locations within the Komadugu-Yobe and Sokoto-Rima River Basins in the Sudano-Sahelian zone of northern Nigeria. Three models were utilised, and analyses were based on Representative Concentration Pathway (RCP) 8.5. Projected changes in mean, level of variability and distribution of rainfall were analysed using the Relative Percentage Change Method and the Precipitation Concentration Index (PCI), while the performance of the models was evaluated using the Nash–Sutcliffe Efficiency (NSE) index. The results show that changes in mean rainfall will be predominantly negative, with a minimum and maximum level of change of ˗1.02 per cent at Nguru, and ˗70.4 per cent at Jos, based on the IPSL-CM5A and HadGEM2-ES models, respectively. The rainy season of the baseline period varied between low and moderate variability, while the near future ranges between low and high levels of variability. The validation indicates acceptable levels of performance, with most values ranging between 0.0 and 1.0. The PCI for the near future suggests that the rainy season will be mainly characterised by uniform and near-uniform rainfall distribution. Hence, the projected negative changes and high variability of rainfall at some locations call for the development of an Adaptive Benefit Mechanism that will minimise future natural resource conflicts.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89544581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The current study focuses on the altering historical rainfall data analysis and its variability in Kolkata (Kolkata Municipal Corporation), a metropolitan city in India. The research area experiences detrimental urban floods (pluvial floods) at near-annual regularity during the monsoon, and during the pre-monsoon seasons it commonly experiences water shortage problems. Analysing trends and temporal variability of rainfall over 120 years from 1901 to 2020 is the main objective of this study. The original Mann–Kendall (M–K) test has been applied to the rainfall dataset in conjunction with Sen’s Slope Estimator using Python 3.10, after the Durbin-Watson (DW) statistic initially suggested that there is no serial correlation effect. The M–K test, with a Kendall’s tau of 0.17058 (significant at a 5% level), shows an upward trend in annual rainfall between 1901 and 2020. The Sen’s slope, which measures the rate of change annually, has a value of 2.48152. Regression analysis and other dispersion measures are also used in this study to investigate the monthly rainfall trend and its variability. The phase-wise (30-year) analysis of annual rainfall variability reveals a considerable variation over 120 years. While fitting the linear regression line month by month over the entire period, mostly negative trends were found in the pre-monsoon and positive trends in the monsoon and post-monsoon seasons. The findings of this analysis could be useful to urban planners for water supply and management in the study area. The primary concern of planners for effectively managing rainwater and the accompanying issues should be the growing variability of annual precipitation.
目前的研究重点是印度大都市加尔各答(Kolkata Municipal Corporation)不断变化的历史降雨数据分析及其变异性。在季风期间，研究区几乎每年都会经历一次有害的城市洪水(雨洪)，在季风前季节，它通常会经历缺水问题。本研究的主要目的是分析从1901年到2020年120年的降水趋势和时间变率。在Durbin-Watson (DW)统计数据最初表明没有序列相关效应之后，原始的Mann-Kendall (M-K)检验已与使用Python 3.10的Sen斜率估计器一起应用于降雨数据集。肯德尔τ值为0.17058(在5%水平上显著)的M-K检验显示，1901年至2020年的年降雨量呈上升趋势。衡量年变化率的森氏斜率的值为2.48152。本研究亦采用回归分析及其他离散度方法探讨月降水趋势及其变异。年降雨量变率的分阶段(30年)分析显示，在120年期间有相当大的变化。逐月拟合的线性回归线显示，季风前和季风后季节多为负趋势，季风前和季风后季节多为正趋势。这一分析的结果可能对研究地区的供水和管理城市规划者有用。规划人员对有效管理雨水及其相关问题的主要关注应该是年降水量的日益变化。
{"title":"Statistical analysis of rainfall trend and its variability (1901–2020) in Kolkata, India","authors":"MD JUBER ALAM, A. Majumder","doi":"10.12775/bgeo-2022-0006","DOIUrl":"https://doi.org/10.12775/bgeo-2022-0006","url":null,"abstract":"The current study focuses on the altering historical rainfall data analysis and its variability in Kolkata (Kolkata Municipal Corporation), a metropolitan city in India. The research area experiences detrimental urban floods (pluvial floods) at near-annual regularity during the monsoon, and during the pre-monsoon seasons it commonly experiences water shortage problems. Analysing trends and temporal variability of rainfall over 120 years from 1901 to 2020 is the main objective of this study. The original Mann–Kendall (M–K) test has been applied to the rainfall dataset in conjunction with Sen’s Slope Estimator using Python 3.10, after the Durbin-Watson (DW) statistic initially suggested that there is no serial correlation effect. The M–K test, with a Kendall’s tau of 0.17058 (significant at a 5% level), shows an upward trend in annual rainfall between 1901 and 2020. The Sen’s slope, which measures the rate of change annually, has a value of 2.48152. Regression analysis and other dispersion measures are also used in this study to investigate the monthly rainfall trend and its variability. The phase-wise (30-year) analysis of annual rainfall variability reveals a considerable variation over 120 years. While fitting the linear regression line month by month over the entire period, mostly negative trends were found in the pre-monsoon and positive trends in the monsoon and post-monsoon seasons. The findings of this analysis could be useful to urban planners for water supply and management in the study area. The primary concern of planners for effectively managing rainwater and the accompanying issues should be the growing variability of annual precipitation.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83566579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Koryak Highlands are a poorly explored area in terms of glaciation and its connection to climate. The purpose of this work is, using Sentinel-2 images (2019), to assess the state of glaciers at present against the background of climatic trends. Spatial patterns of trends of mean summer and annual temperatures, total precipitation and precipitation for the cold period from 1966 to 2019 were compiled: the temperature trends increase towards the Kamchatka Peninsula, and the mean summer temperature trends increase from 2 to 3°C. Precipitation trends increase from the continent to the coastal zone, with cold season trends changing from 0 to minus 50 mm. As a result, 212 glaciers and 279 rock glaciers were discovered in the Highlands, whereas 112 objects that had previously been recognised were not identified: either there is no glacier, or its area is less than 0.001 km2. The reduction in glacier areas compared to the USSR Glacier Inventory (1960s) varies widely by river basin, from 35 to 74%. The mean present glacier area varies from basin to basin from 0.4 to 0.11 km2. The glaciers are mainly corrie type of the N, NE and NW aspects. The change of average glacier firn line is from several tens of metres to 400–500 m.
{"title":"Glaciers of the Koryak Highlands: assessment of the state using satellite images and field studies","authors":"M. Ananicheva, A. Aleinikov","doi":"10.12775/bgeo-2022-0004","DOIUrl":"https://doi.org/10.12775/bgeo-2022-0004","url":null,"abstract":"The Koryak Highlands are a poorly explored area in terms of glaciation and its connection to climate. The purpose of this work is, using Sentinel-2 images (2019), to assess the state of glaciers at present against the background of climatic trends. Spatial patterns of trends of mean summer and annual temperatures, total precipitation and precipitation for the cold period from 1966 to 2019 were compiled: the temperature trends increase towards the Kamchatka Peninsula, and the mean summer temperature trends increase from 2 to 3°C. Precipitation trends increase from the continent to the coastal zone, with cold season trends changing from 0 to minus 50 mm. As a result, 212 glaciers and 279 rock glaciers were discovered in the Highlands, whereas 112 objects that had previously been recognised were not identified: either there is no glacier, or its area is less than 0.001 km2. The reduction in glacier areas compared to the USSR Glacier Inventory (1960s) varies widely by river basin, from 35 to 74%. The mean present glacier area varies from basin to basin from 0.4 to 0.11 km2. The glaciers are mainly corrie type of the N, NE and NW aspects. The change of average glacier firn line is from several tens of metres to 400–500 m.","PeriodicalId":43256,"journal":{"name":"Bulletin of Geography-Physical Geography Series","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76998950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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