Trends and fluctuations of rainfall regime in the Brahmaputra and Barak basins of Assam, India

Severe weather conditions create negative impacts on humans. One of the severe weather conditions is storms. In the scope of this study, the storm effects on the Marmara Region were investigated using data for the period 2000 to 2010 giving the hourly averaged wind direction and speed in the Marmara Region, as provided by the Turkish Meteorological Service. The monthly distribution of storms has been estimated and their daily variability has been investigated. Additionally, air masses that cause storms have been determined by using NCEP/NCAR re-analysis data. Other than this, by studying the storms, extreme values have been ascertained and northerly values from these storm values (since in percentage terms they are larger) and hourly variability in a single day for 17 weather stations have been depicted graphically. The days that northerly storms reached extreme values are shown with the meteorological maps (surface chart, 850, 700, 500, and 300 hPa) and the temperature diagrams for Istanbul in the Marmara Region have been examined and analysed.     

Simulation Of Salt-Water Encroachment In A Multi-Layer Groundwater System,Bangkok, Thailand

Salt-water encroachment in the multi-layer groundwater system underlying the Bangkok metropolitan area was simulated with a quasi-three-dimensional flow and solute-transport model. The quasi-three-dimensional model used in this study is based on the model SUTRA. Accurate conceptualization of the initial state of the system with regard to the distribution of salt-water concentration is very important for modeling, especially in areas where localized zones of high salt concentration exist in the groundwater. Data adequacy and model results were evaluated by a geostatistical analysis. The model is capable of simulating the regional trend of potentiometric levels and salt concentration. However, lack of monitoring data in areas where localized zones of high salt concentration exist resulted in large model residuals. RÉSUMÉ: L'empiétement des eaux salées dans le système hydrologique multi-couche sous-jacent la zone métropolitaine de Bangkok a été simulé à l'aide d'un modèle quasi-tridimensionnel représentant l'écoulement des eaux et le transport d'éléments en solution. Le modèle quasi-tridimensionnel utilisé dans cette étude est basé sur le modèle SUTRA. Une conceptualisation exacte de l'état initial du système en ce qui concerne la répartition de la concentration des eaux salines est très important, particulièrement dans les endroits localisés où l'eau souterraine presente une forte concentration en sel. La qualité des donnés et des résultats a été estimée à l'aide d'une analyse géostatistique. Le modèle est capable de simuler la tendance régionale des niveaux potentiométriques et de la concentration en sel. Cependant, le manque de données de contrôle dans les endroits à forte concentration a donné lieu à des résiduels importants. RESUMEN: La intrusión de agua salina en el sistema multicapa bajo el área metropolitana de Bangkok se simuló mediante un modelo de flujo y transporte de solutos casi-tridimensional, basado en el modelo SUTRA. La conceptualizacián precisa de la distribución inicial de concentraciones de agua salina es muy importante para el modelo, especialmente en áreas donde existen zonas locales de alta concentración salina en el agua subterránea. La exactitud de los datos y del modelo se evaluaron mediante un análisis geoestadístico. El modelo permite simular la tendencia regional de los niveles piezométricos y la concentración de sales. Sin embargo, la falta de datos de muestreo en las zonas locales de alta salinidad resultaron en valores altos de los residuos calculados por el modelo.     

The green revolution and poverty: a theoretical and empirical examination of the relation between technology and society

The paper deals with the effects of the green revolution (GR) technology on poverty both conceptually and empirically. It provides a brief overview of the GR debate and then presents a `slice' of this debate in detail - in particular, Lipton's and others' views on the supposed positive and negative benefits of the GR for the poor. The paper then provides a provocative critique of this literature for its underlying neo-Malthusianism of a specific type, for ignoring class issues in the analysis of the GR-poverty relation, and for treating this relation as a necessary relation. It subsequently presents an alternative statement on the GR-poverty issue, arguing that it is class relations that set limit within which population and technology work and affect poverty and that the GR-poverty relation is a contingent one, rather than necessary. In the light of the paper's criticisms and the alternative view it provides, a statistical analysis of the relation between the GR and the population factor on the one hand and poverty level and poverty reduction on the other in India is performed. This analysis is generally consistent with the paper's critique of the Liptonian framework.     

Developing synergy regression models with space-borne ALOS PALSAR and Landsat TM sensors for retrieving tropical forest biomass

Forest stand biomass serves as an effective indicator for monitoring REDD (reducing emissions from deforestation and forest degradation). Optical remote sensing data have been widely used to derive forest biophysical parameters inspite of their poor sensitivity towards the forest properties. Microwave remote sensing provides a better alternative owing to its inherent ability to penetrate the forest vegetation. This study aims at developing optimal regression models for retrieving forest above-ground bole biomass (AGBB) utilising optical data from Landsat TM and microwave data from L-band of ALOS PALSAR data over Indian subcontinental tropical deciduous mixed forests located in Munger (Bihar, India). Spatial biomass models were developed. The results using Landsat TM showed poor correlation (R² = 0.295 and RMSE = 35 t/ha) when compared to HH polarized L-band SAR (R² = 0.868 and RMSE = 16.06 t/ha). However, the prediction model performed even better when both the optical and SAR were used simultaneously (R² = 0.892 and RMSE = 14.08 t/ha). The addition of TM metrics has positively contributed in improving PALSAR estimates of forest biomass. Hence, the study recommends the combined use of both optical and SAR sensors for better assessment of stand biomass with significant contribution towards operational forestry.     

A steady state model of the Somali current

A steady state model of the Somali current including forcing by both the curl and the divergence of the wind stress is discussed. The model equations are linear, but the results presented are for the one nonlinear case. The grid resolution was 12 km in the zonal and 24 km in the meridional direction. The streamfunction and velocity potential of the current are presented for forcing by divergence and compared with a situation when only the curl is present. The results indicate that a two-gyre system appears in July, a representative month for the summer monsoon, only when divergence is included. Computations with available data indicate that the divergence is comparable in magnitude to the curl near the location of the Somali current. The model produces three other important features: (i) strong upwelling off the east coast of Africa, (ii) downwelling over central Arabian sea and (iii) a strong eastward current in the upper layer towards the interior of the Arabian sea near 12°N.     

Control of climate and Tethyan legacy on distribution of Paleocene–Eocene gastropods and establishment of the Northern Tropical Realm

Palaeobiogeographical distribution of gastropod genera from the Paleocene and the Eocene has been analysed. Based on this distribution, formal palaeobiogeographical provinces have been established and their relationships are sought. It has been found that the provinces were largely restricted to the palaeo-tropics and subtropics mainly of the northern hemisphere and they share a large proportion of their generic composition. The Northern Tropical Realm has been established to include these provinces. The distribution evinces presence of ocean surface currents in the tropics across longitudes. The possible currents moved through the relict Tethys Ocean, across the Atlantic Ocean and perhaps also across the Pacific. However, planktotrophic larvae of these benthic molluscs could not cross the deep ocean barrier that lay between the Northern Tropical Realm and the Austro-New Zealand Province of the southern hemisphere. The gastropod fauna in the latter province evolved independently. Distribution of all the provinces within palaeo-tropics and subtropics indicates strong control of temperature over it. Paleocene–Eocene Thermal Maximum appears to be responsible for extinction and range contraction of high latitude faunas. Low latitude faunas also suffered significant extinction. However, large diversification in the Eocene was a response to widespread transgression that coincided with the thermal event.     

Bankline change and the facets of riverine hazards in the floodplain of Subansiri–Ranganadi Doab, Brahmaputra Valley, India

Subansiri?CRanganadi Doab (confluence country), located in Lakhimpur district, Assam, is one of the worst flood-affected areas in Brahmaputra valley. The Doab is well populated, and land around these rivers is extensively used for cultivation. As means of flood protection, embankments were constructed in the 1950s along the banks of both the rivers. On the other hand, these rivers are dynamic in terms of banklines and other forms of channel changes. Progressive migration of bankline, due to erosion, results in loss of cultivable land. Moreover, it causes breaches in the embankments increasing the severity of flood in the Doab. This paper attempts to study the changes in the banklines of two major rivers in the floodplains of the Subansiri?CRanganadi Doab during 1997?C2009 in the context of the riverine hazards it brings to the floodplain dwellers. The shift of the banklines in Subansiri?CRanganadi Doab, downstream of North Lakhimpur, has been estimated using IRS LISS imageries of 1997 and 2009 in GIS environment. The river Subansiri during the study period has migrated westward and has widened substantially resulting in erosion of an area of ~19.137?km². For Ranganadi, the total area that has been eroded due to channel changes is ~0.897?km². The channel changes are mainly due to concave bank erosion associated with high stages of flow. Channel widening in Subansiri and Ranganadi in the study area during the decades of 1990s and 2000 has led to frequent breaches in the embankments. Lateral erosion and inundation due to embankment failure are the most dominant facets of riverine hazards in the study area as these lead to loss of livelihood. Therefore, it is necessary to incorporate geomorphic changes in formulating flood management programmes.     

Bacterial biosurfactants can be an ecofriendly and advanced technology for remediation of heavy metals and co-contaminated soil

Environmental pollution due to heavy metals has become a significant drawback as a result of their ecotoxicity. Hence, their remediation is of pressing concern. Many technologies are planned for their remediation; however, most of them are highly expensive and result in incomplete removal of contaminants. So, massive attention has paid to the event and application of the latest biologically techniques, that is effective in remedy and cost, not harming the prevailing surroundings. Hence, application of biosurfactant in heavy metal remediation is one among the recent ecofriendly technique. The present review critically highlights bacterial biosurfactants as a best alternative technique for heavy metals remediation. The review also emphasizes that bacterial biosurfactants can open up a new vista in remediation of metal-contaminated soil.