Recent Sea Level and Sea Surface Temperature Trends Along the Bangladesh Coast in Relation to the Frequency of Intense Cyclones

The French Transportable Laser Ranging System (FTLRS) was deployed in the calibration site of satellite radar altimeters in Corsica over the 2002 and 2005 campaigns. The paper describes the different steps of SLR data processing. The average arcs RMS obtained are about 1–2 cm for Lageos-1&;-2, Starlette and Stella satellites; it is shown that the best results of satellite orbits determination and geocentric positioning are obtained with Eigen-Grace03s gravity model. The difference of FTLRS absolute 3D positioning, between 2002 and 2005, of about 7.7 mm (i.e., 2.6 mm/yr) is less than residual errors of ITRF2005 velocities (of about 4.3 mm/yr).     

Wave‐induced instability of seabed: Mechanism and conditions

Abstract

The instability of the seabed constitutes an important consideration in the planning and design of various offshore facilities. The stresses and the pore water pressure in the sediments, induced by the action of waves during a storm, may cause them to fail, leading to seabed instability. In this article the possible mechanism of such failures are discussed and the conditions necessary for them are formulated through simplified analyses. These provide the combinations of wave, site, and sediment parameters likely to cause instability, which may be used to identify potentially unstable sediments in a given offshore region during a storm. The numerical results are presented in convenient graphical form. Some illustrative field studies are also presented.     

Flooding and its relationship with land cover change,population growth,and road density

Bangladesh experiences frequent hydro-climatic disasters such as flooding.These disasters are believed to be associated with land use changes and climate variability.However,identifying the factors that lead to flooding is challenging.This study mapped flood susceptibility in the northeast region of Bangladesh using Bayesian regularization back propagation(BRBP)neural network,classification and regression trees(CART),a statistical model(STM)using the evidence belief function(EBF),and their ensemble models(EMs)for three time periods(2000,2014,and 2017).The accuracy of machine learning algorithms(MLAs),STM,and EMs were assessed by considering the area under the curve-receiver operating char-acteristic(AUC-ROC).Evaluation of the accuracy levels of the aforementioned algorithms revealed that EM4(BRBP-CART-EBF)outperformed(AUC＞90％)standalone and other ensemble models for the three time periods analyzed.Furthermore,this study investigated the relationships among land cover change(LCC),population growth(PG),road density(RD),and relative change of flooding(RCF)areas for the per-iod between 2000 and 2017.The results showed that areas with very high susceptibility to flooding increased by 19.72％between 2000 and 2017,while the PG rate increased by 51.68％over the same period.The Pearson correlation coefficient for RCF and RD was calculated to be 0.496.These findings highlight the significant association between floods and causative factors.The study findings could be valuable to policymakers and resource managers as they can lead to improvements in flood management and reduction in flood damage and risks.     

Substantiation of debris flow velocity from super-elevation: a numerical approach

The use of super-elevations that a forced vortex flow leaves on the valley walls of a curved flume is a plausible approach toward estimating debris flow velocities in earthquake-induced geo-hazard studies. The centrifugal force of a speeding flow is responsible for a higher flow depth on the outer bend. However, in reality, a flow is not steady, and only the highest flow-marks are left at the outer and inner bends of the flow, which can lead to an inaccurate estimation of the actual velocity. Seeing the real scenario of the field, a series of numerical flume tests using smoothed particle hydrodynamics (SPH) is conducted to validate the estimation of debris flow velocities from flow-marks. Velocities estimated from flow-marks are lower than real velocities near the source region, but they converge to real velocities as the distance to the source increases. Based on several simulations, a best-fit line is proposed for adjusting debris flow velocity from mud-marks, and it is used to estimate flow velocities of the well-documented debris event called “Shiraito river debris flow,” which happened near the rim of the Hakone Crater, Kanagawa Prefecture, Japan, ensuing from the 1923 Great Kanto earthquake.     

Levels of Organochlorine Pesticide Residues in Some Organs of the Ganges Perch, Lates calcarifer, from the Ganges–Brahmaputra–Meghna Estuary, Bangladesh

Levels of organochlorine pesticide residues (p,p′ DDT, DDD, DDE, Aldrin, Dieldrin, Lindane, Heptachlor and BHC) were analysed in the dry and wet seasons in four organs (muscle, liver, gut and egg samples) of Ganges Perch, Lates calcarifer, collected during October–November–December, 1996 and May–June–July, 1997 from the Ganges–Brahmaputtra–Meghna estuary. The residues were analysed by using gas-chromatography (GC) in electron capture detector (ECD) mode and were verified by thin layer chromatography (TLC). Among the four organs analysed, the residues were found in the order egg > gut > muscle > liver. The pesticide residues were found in the order ∑DDT > Heptachlor >Dieldrin > Aldrin. Higher levels of residues were found during the dry season due to high lipid content in fishes. A positive correlation was observed between the pesticide residues (∑DDT and ∑OCs) and lipid contents of fish, and the correlation was found to be linear. The concentrations of pesticide residues in muscle, liver and gut were below the FAO/WHO (1993) recommended permissible limit except in eggs.     

Rural development planning in Pakistan

Summary and Perspectives Most of the rural development plans and green revolution technology attempted in Pakistan between the years 1950 and 1970 were a part of induced transformations and institutional innovations. These attempts did bring some advances in productivity in Pakistan. In recent years, Panjab broke the international records in wheat production. But, a review of rural development efforts and wide application of induced innovations provide mixed results. Since 1972, the Integrated Rural Development has been adopted as a model for country's agrarian reforms, because of the gains at Shadab Project. The success of Shadab was impressive indeed, but Pakistan's economy, history, and society call for caution and raise scepticism, as were rightly pointed out byRuttan (12) for Integrated Rural Development Program.Success of Shadab Project was in large part due to well guided input of human resources devoted to organizational, management and technical assistance. Extensive extension services, model demonstration farms, publicity, and the training of farmers in various new techniques of agriculture were provided. The history of other development efforts prove that similar intensity of resource input cannot be maintained, when the program is generalized.Furthermore, the administrative freedom usually available in pilot projects of limited geographic extent to tailor programs precisely to local, national, and human endowments is usually not available in widespread use due to administrative inconveniences. Likewise, resources of physical, and institutional infrastructure are likely to diminish when the program is spread widely. Another perspective which worries the historical-cultural geographers is the dominant cultural attitudes and preferences of the village people in Pakistan.Pakistani way of life does not set man so much against the nature, as he often has been in the western world. Man is viewed as a part of nature, who can be happy and successful if he adjusts himself to his habitat. Rural Pakistan values leisure as an end in itself, and believes in its predestiny as set by one's luck. This luck-leisure attitude is one of the graces of rural Pakistan, and often serves as an impediment to quick induced changes, which did not evolve from within their own society.Deh Nareja, which this author is studying for the past 23 years as his laboratory to study rural changes, is a good example. Deh Nareja is an assemblage for six villages, with about 1000 people, located 15 km southwest of Tatta. The Deh is linked with Tatta, a tourist town and headquarter of the district administration, by a canal path and a surfaced road. Proximity and spatial linkage with Tatta have made the people of Deh Nareja more mobile, than their counterparts in other villages. In spite of this interchange, and exposure of farmers to other ways of life in the town, Deh Nareja remains a repository of traditional values, and traditional agriculture.Comparison of two maps of Deh Nareja, substantiates this point (Fig. 2). In order to improve the field ditches and save the water lost to seepage and spills, a survey was done in early 1960, to lay the fields in a rectangular pattern. Equal amount of land which belonged to a farmer as an irregular field was given to the farmer in a rectangular pattern (Fig 3). It took considerable amount of time and resources to accomplish the task, but the rural people resisted this change to the extent that the entire plan had to be abandoned. The traditional sentimental love of one's own land, its hereditary linkage were far more important than an efficient irrigation and agriculture.However, consequent to March 1972 land reforms, certain changes were visible in the attitude of the farmers. During a visit again to Deh Nareja and to a number of other villages in Pakistan in the summer of 1976, a certain optimism and hope was noticeable amongst the villagers. The farmers seemed to be more conscious of their rights; they were more aggressive, and were looking forward to a better future. Comparing with their former subdued and downtrodden condition, their changed situation and perceptions can better be expressed by the term agro-nauts. The term agro-naut is introduced here for the present conscious, partly reliant, and aggressive farmers, as against subdued, downtrodden and exploited peasants. Like astronauts, these agro-nauts still do not know their destiny or ramifications of induced changes, but seem to be prepared to accomplish something new. The first ever national conference of agro-nauts convened at Mandi Bahauddin, Panjab, and adoption of a national farmers charter were the steps in the right direction to enhance the confidence of the agro-nauts.Under this changed situation, the Integrated Rural Development Program, seems to have some potential, if environmental, cultural and historical roots of Pakistan are not ignored, and package transformations are induced without destroying the present producing ability of the farmers.     

APPLICABILITY OF THE BEND DEVELOPMENT THEORY IN NATURAL ALLUVIAL RIVERS

1 INTRODUCTION Meanders are the fundamental planform of alluvial rivers and bank erosion in the meander bends is a common feature. In most of the practical cases, the eroded material from the outer bank deposits along the inner bank to develop sand bars. Very often, bank erosion is drastic and channel width increases in an order of several hundred meter per year at some reaches of large scale meandering rivers, for example, the Ganges river inside Bangladesh, as noticed by Muramoto and…     

Landslides and stability of coastal cliffs of Cox's Bazar area,Bangladesh

Successive applications of two-dimensional circular slip limit equilibrium analysis of slices have been made to the three sections of the Cox's Bazar Coastal Cliff. These three sections have been found to be stable (S), quasistable (QS), and unstable (U) with factors of safety (Fs) of 1.269 ± 0.01, 1.13 ± 0.0504, and 1.01 ± 0.058, respectively. In the quasistable and unstable sections, the slopes suffered shallow slidings with slip circles parallel to the surface of slopes.The main causes of these slidings are steepness of slopes, lack of vegetation cover, erosion of toe accumulations by run-off water and waves during high tides. The influence of the slope geometry and the material's strength properties of slopes on safety factors are evaluated. The steeper cliffs reach an unstable condition faster than the more gentle cliffs as their heights change by an equal amount. Again, the high cliffs reach an unstable condition faster than the lower cliffs as slope inclinations change by an equal amount. The safety factor increases with a corresponding increase of friction angle (ø°) and vice versa.Abbreviations BK Bahar chara to Kalatali chara - KR Kalatali chara to Reju khal - RI Reju khal to Boro Inani khal - Fs Factor of Safety - S Stable - QS Quasistable (semistable) - US Unstable     

沉积岩数据库:计算机的应用

岩石学数据在许多地质统计分析中是相当有用的。为了得出焦伊布尔哈德地区的焦因蒂亚布尔区和锡尔赫特地区焦伊布尔哈德灰岩区的构造、地层和沉积作用情况，已作了大量的详细的野外工作和室内分析。已对锡尔赫特地区和焦伊布尔哈德地区的灰岩作了化学分析，且对Ｔｉｐａｍ砂岩作了矿物分析。所获取数据可应用于ＳＥＤＢＡ。用于ＳＥＤＢＡ的参数必须是精确的和沉积成因的。