Identifying baseflow source areas using remotely sensed and ground-based hydrologic data     

Aakash Ahamed  Rosemary Knight  Sarfaraz Alam 《水文研究》2024,38(2):e15056

Understanding how rainfall and snowmelt influence baseflow, the groundwater-fed component of streamflow, is essential for sound water resources management. Current approaches to understand the spatial couplings between these processes and baseflow are limited. The most commonly used methods include geochemical tracers and hydrologic models. A key limitation of the first is cost, while the second is limited by the need for simplifying assumptions. This study developed a data-driven approach which leverages satellite Earth observation data and ground-based data to assess the degree to which baseflow is influenced by upstream rainfall and snowmelt in California's Sierra Nevada. The procedure involved: (1) separation of baseflow from streamflow time series using a low-pass filtering technique, (2) quantification of aquifer drainage timescales through baseflow recession analysis, (3) application of time series and information theory methods to identify the areas which have the greatest impacts on baseflow through both rainfall and snowmelt, and (4) characterization of the elevation zones which have a prevailing influence on baseflow. Results suggest that areas which have the strongest impact on baseflow through rainfall and snowmelt are not necessarily the areas which experience the highest annual rates of snowmelt or rainfall; snowmelt occurring in the 3000–3700 m elevation range was found to be the most important driver of baseflow.  相似文献   

Spatio-temporal variation and sensitivity analysis of aerosol particulate matter during the COVID-19 phase-wise lockdowns in Indian cities     

Ahamed Ibrahim S.N.  Sri Shalini S  Ramachandran A  Palanivelu K 《Journal of Atmospheric Chemistry》2022,79(1):39-66

Journal of Atmospheric Chemistry - At the pandemic of COVID-19, the movement of business and other non-essential activities were majorly restricted at the end of March 2020 in India and continued...  相似文献   

Following things of rubbish value: End-of-life ships, ‘chock-chocky’ furniture and the Bangladeshi middle class consumer   总被引：2，自引：0，他引：2  

N. Gregson  M. Crang  F. Ahamed  N. Akhter  R. Ferdous 《Geoforum》2010,41(6):846-854

There has been an upsurge of geographical work tracing globalised flows of commodities in the wake of Appadurai’s (1986) call to ‘follow the things’. This paper engages with calls to follow the thing but argues that work thus far has been concentrated, first, on global flows from developing world producers to developed world consumers, and, second, on things that remain stable as they circulate. This paper instead argues that ‘follow the thing’ research needs to also attend to flows ‘down’ the value chain, from developed to less developed worlds, and to things that are either coming apart or being disassembled. The case presented here is end-of-life ships, sent to be broken in less developed countries, as most are, in this case in Bangladesh. It looks at how the arts of transience re-work materials from rubbish value ships into new forms and objects in the household furnishing sector, which are then appropriated by Bangladeshi middle class consumers. Far from being a minor feature this is shown to be empirically a significant component of the Bangladeshi economy. Theoretically the paper challenges many habitual assumptions about global flows of commodities and urges ‘follow the thing’ research to rethink the thing. Paying attention to the back-end of the value chain shows that things are but temporary configurations of material. At best partially stable, things are argued to be endlessly being assembled, always becoming something else somewhere else.  相似文献   

Study of radon in soil gas,trace elements and climatic parameters around South Kordofan state,Sudan     

Hajo Idriss  Isam Salih  Abdulaziz S. Alaamer  M. Y. Abdelgalil  Salih Ali Salih  Amna M. Hasan  Mohammed A. ELtahir  Mustafa M. O. Ahamed 《Environmental Earth Sciences》2014,72(2):335-339

This study was conducted primarily to measure and map radon activity concentration in soil gas and to understand the effect of geology and lithology and meteorology on radon concentration. Portable radon meter has been used for the measurement of soil gas radon at 30 different locations around Uro and Korn area in eastern Nuba Mountain South Kordofan State. The results indicate that the activity concentrations of ²²²Rn in soil gas fall within the range of 20–1,359 Bq/m³ with geometric mean of 102.80 Bq/cm³. The obtained data show that samples around Uro have anomaly of ²²²Rn concentrations than the sample around Korn. The reason could be attributed to differences in the geological structure, lithology and climate parameters. GIS predicative map has shown that the elevated levels of radon concentration were measured in North study area. Upon comparing the results with global data, it was found that the obtained values are far below the reported range of India, Slovenia, Portugal and Syria. However, the range of ²²²Rn concentrations in the soil observed in this study is significantly high relative to similar data reported from Libya. The regression analysis has shown that no correlation was noted between radon concentrations, climatic parameters and trace element.  相似文献   

Groundwater arsenic contamination in Manipur,one of the seven North-Eastern Hill states of India: a future danger   总被引：1，自引：0，他引：1  

Dipankar Chakraborti  E. Jayantakumar Singh  Bhaskar Das  Babar Ali Shah  M. Amir Hossain  Bishwajit Nayak  Sad Ahamed  N. Rajmuhon Singh 《Environmental Geology》2008,56(2):381-390

Manipur State, with a population of 2.29 million, is one of the seven North-Eastern Hill states in India, and is severely affected by groundwater arsenic contamination. Manipur has nine districts out of which four are in Manipur Valley where 59% of the people live on 10% of the land. These four districts are all arsenic contaminated. We analysed water samples from 628 tubewells for arsenic out of an expected total 2,014 tubewells in the Manipur Valley. Analyzed samples, 63.3%, contained >10 μg/l of arsenic, 23.2% between 10 and 50 μg/l, and 40% >50 μg/l. The percentages of contaminated wells above 10 and 50 μg/l are higher than in other arsenic affected states and countries of the Ganga–Meghna–Brahmaputra (GMB) Plain. Unlike on the GMB plains, in Manipur there is no systematic relation between arsenic concentration and the depth of tubewells. The source of arsenic in GMB Plain is sediments derived from the Himalaya and surrounding mountains. North-Eastern Hill states were formed at late phase of Himalaya orogeny, and so it will be found in the future that groundwater arsenic contamination in the valleys of other North-Eastern Hill states. Arsenic contaminated aquifers in Manipur Valley are mainly located within the Newer Alluvium. In Manipur, the high rainfall and abundant surface water resources can be exploited to avoid repeating the mass arsenic poisoning that has occurred on the GMB plains.  相似文献   

Groundwater arsenic contamination in Ganga–Meghna–Brahmaputra plain, its health effects and an approach for mitigation     

Dipankar Chakraborti  Mohammad Mahmudur Rahman  Bhaskar Das  Bishwajit Nayak  Arup Pal  Mrinal Kumar Sengupta  Md. Amir Hossain  Sad Ahamed  Manabendranath Sahu  Kshitish Chandra Saha  Subhash Chandra Mukherjee  Shyamapada Pati  Rathindra Nath Dutta  Quazi Quamruzzaman 《Environmental Earth Sciences》2013,70(5):1993-2008

The authors’ survey of the Ganga–Meghna–Brahmaputra (GMB) plain (area 569,749 km²; population >500 million) over the past 20 years and analysis of more than 220,000 hand tube-well water samples revealed groundwater arsenic contamination in the floodplains of the Ganga–Brahmaputra river (Uttar Pradesh, Bihar, Jharkhand, West Bengal, and Assam) in India and the Padma–Meghna–Brahmaputra river in Bangladesh. On average, 50 % of the water samples contain arsenic above the World Health Organization guideline value of 10 μg/L in India and Bangladesh. More than 100 million people in the GMB plain are potentially at risk. The authors’ medical team screened around 155,000 people from the affected villages and registered 16,000 patients with different types of arsenical skin lesions. Arsenic neuropathy and adverse pregnancy outcomes have been recorded. Infants and children drinking arsenic-contaminated water are believed to be at high risk. About 45,000 biological samples analyzed from arsenic-affected villages of the GMB plain revealed an elevated level of arsenic present in patients as well as non-patients, indicating that many are sub-clinically affected. In West Bengal and Bangladesh, there are huge surface water in rivers, wetlands, and flooded river basins. In the arsenic-affected GMB plain, the crisis is not over water scarcity but about managing the available water resources.  相似文献   

On the calculation of magnetic anomalies of irregular two-dimensional bodies     

B. S. R. Rao  I. V. Radhakrishna Murthy  K. S. M. A. Ahamed 《Pure and Applied Geophysics》1973,110(1):2066-2069

Summary An easy method of calculating the magnetic anomalies of two-dimensional irregular bodies is presented. The body under consideration is replaced by a set of line doublets with a pole strength equal to the intensity of magnetisation and parallel to its direction. The magnetic effects of some of the equally spaced doublets are obtained, added and multiplied by the distance between them to yield the magnetic anomaly. The expressions involved here are simpler than those existing in geophysical literature.  相似文献   

Land suitability analysis for maize production in Indonesia using satellite remote sensing and GIS-based multicriteria decision support system     

Habibie  Muhammad Iqbal  Noguchi  Ryozo  Shusuke  Matsushita  Ahamed  Tofael 《GeoJournal》2021,86(2):777-807

GeoJournal - Maize is one of the potential crops can help in regional food production with self-sufficiency of foods in the drought prone areas of East Java in Indonesia. The purpose of this...  相似文献