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      Volume 124, Issue 1

      February 2015,   pages  1-281

    • Climatology and trends of summer high temperature days in India during 1969–2013

      A K Jaswal P C S Rao Virendra Singh

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      Based on the daily maximum air temperature data from 176 stations in India from 1969 to 2013, the climatological distribution of the number of days with high temperature (HT) defined as days with maximum temperature higher than 37°C during summer season (March–June) are studied. With a focus on the regional variability and long-term trends, the impacts of HT days are examined by dividing the country into six geographical regions (North, West, North-central, East, South-central and South). Although the long-term (1969–2013) climatological numbers of HT days display well-defined spatial patterns, there is clear change in climatological mean and coefficient of variation of HT days in a recent period (1991–2013). The long period trends indicate increase in summer HT days by 3%, 5%, and 18% in north, west, and south regions, respectively and decrease by 4% and 9% in north-central and east regions respectively. However, spatial variations in HT days exist across different regions in the country. The data analysis shows that 2010 was the warmest summer year and 2013 was the coolest summer year in India. Comparison of spatial distributions of trends in HT days for 1969–1990 and 1991–2013 periods reveal that there is an abrupt increase in the number of HT days over north, west and north-central regions of India probably from mid 1990s. A steep increase in summer HT days in highly populated cities of Mumbai, New Delhi, Chennai, Jaipur, and Visakhapatnam is noticed during the recent period of 1991–2013. The summer HT days over southern India indicate significant positive correlation with Nino 3.4 index for three months’ running mean (December–January–February, January–March, February–April, March–May and April–June).

    • Statistical analysis of long term spatial and temporal trends of temperature parameters over Sutlej river basin, India

      Dharmaveer Singh R D Glupta Sanjay K Jain

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      The annual and seasonal trend analysis of different surface temperature parameters (average, maximum, minimum and diurnal temperature range) has been done for historical (1971–2005) and future periods (2011–2099) in the middle catchment of Sutlej river basin, India. The future time series of temperature data has been generated through statistical downscaling from large scale predictors of CGCM3 and HadCM3 models under A2 scenario. Modified Mann–Kendall test and Cumulative Sum (CUSUM) chart have been used for detecting trend and sequential shift in time series of temperature parameters. The results of annual trend analysis for period of 1971–2005 show increasing as well as decreasing trends in average ($T_{\text{Mean}}$), maximum ($T_{\text{Max}}$), minimum ($T_{\text{Min}}$) temperature and increasing trends in Diurnal Temperature Range (DTR) at different stations. But the annual trend analysis of downscaled data has revealed statistically significant (95% confidence level) rising trends in $T_{\text{Mean}}$, $T_{\text{Max}}$, $T_{\text{Min}}$ and falling trend in DTR for the period 2011–2099. The decreasing trend in DTR is due to higher rate of increase in $T_{\text{Min}}$ compared to $T_{\text{Max}}$.

    • Simulation of the Tornado Event of 22 March, 2013 over Brahmanbaria, Bangladesh using WRF Model with 3DVar DA techniques

      M N Ahasan M M Alam S K Debsarma

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      A severe thunderstorm produced a tornado (F2 on the enhanced Fujita–Pearson scale), which affected the Brahmanbaria district of Bangladesh during 1100–1130 UTC of 22 March, 2013. The tornado consumed 38, injured 388 and caused a huge loss of property. The total length travelled by the tornado was about 12–15 km and about 1728 households were affected. An attempt has been made to simulate this rare event using the Weather Research and Forecasting (WRF) model. The model was run in a single domain at 9 km resolution for a period of 24 hrs, starting at 0000 UTC on 22 March, 2013. The meteorological conditions that led to form this tornado have been analyzed. The model simulated meteorological conditions are compared with that of a ‘no severe thunderstorm observed day’ on 22 March, 2012. Thus, the model also ran in the same domain at same resolution for 24 hrs, starting at 0000 UTC on 22 March, 2012. The model simulated meteorological parameters are consistent with each other, and all are in good agreement with the observation in terms of the region of occurrence of the tornado activity. The model has efficiently captured the common favourable synoptic conditions for the occurrence of severe tornadoes though there are some spatial and temporal biases in the simulation. The wind speed is not in good agreement with the observation as it has shown the strongest wind of only 15–20 ms−1, against the estimated wind speed of about 55 ms−1. The spatial distributions as well as intensity of rainfall are also in good agreement with the observation. The results of these analyses demonstrated the capability of high-resolution WRF model with 3DVar Data Assimilation (DA) techniques in simulation of tornado over Brahmanbaria, Bangladesh.

    • Uncertainty in a monthly water balance model using the generalized likelihood uncertainty estimation methodology

      Diego Rivera Yessica Rivas Alex Godoy

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      Hydrological models are simplified representations of natural processes and subject to errors. Uncertainty bounds are a commonly used way to assess the impact of an input or model architecture uncertainty in model outputs. Different sets of parameters could have equally robust goodness-of-fit indicators, which is known as Equifinality. We assessed the outputs from a lumped conceptual hydrological model to an agricultural watershed in central Chile under strong interannual variability (coefficient of variability of 25%) by using the Equifinality concept and uncertainty bounds. The simulation period ran from January 1999 to December 2006. Equifinality and uncertainty bounds from GLUE methodology (Generalized Likelihood Uncertainty Estimation) were used to identify parameter sets as potential representations of the system. The aim of this paper is to exploit the use of uncertainty bounds to differentiate behavioural parameter sets in a simple hydrological model. Then, we analyze the presence of equifinality in order to improve the identification of relevant hydrological processes. The water balance model for Chillan River exhibits, at a first stage, equifinality. However, it was possible to narrow the range for the parameters and eventually identify a set of parameters representing the behaviour of the watershed (a behavioural model) in agreement with observational and soft data (calculation of areal precipitation over the watershed using an isohyetal map). The mean width of the uncertainty bound around the predicted runoff for the simulation period decreased from 50 to 20 m3s−1 after fixing the parameter controlling the areal precipitation over the watershed. This decrement is equivalent to decreasing the ratio between simulated and observed discharge from 5.2 to 2.5. Despite the criticisms against the GLUE methodology, such as the lack of statistical formality, it is identified as a useful tool assisting the modeller with the identification of critical parameters.

    • Analysis of drought areas in northern Algeria using Markov chains

      Mourad Lazri Soltane Ameur Michel Brucker Maurad Lahdir Mounir Sehad

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      The present work studies the trends in drought in northern Algeria. This region was marked by a severe, wide-ranging and persistent drought due to its extraordinary rainfall deficit. In this study, drought classes are identified using SPI (standardized precipitation index) values. A Markovian approach is adopted to discern the probabilistic behaviour of the time ser ies of the drought. Thus, a transition probability matrix is constructed from drought distribution maps. The trends in changes in drought types and the distribution area are analyzed. The results show that the probability of class severe/extreme drought increases considerably rising from the probability of 0.2650 in 2005 to a stable probability of 0.5756 in 2041.

    • Decision Support System integrated with Geographic Information System to target restoration actions in watersheds of arid environment: A case study of Hathmati watershed, Sabarkantha district, Gujarat

      Dhruvesh P Patel Prashant K Srivastava Manika Gupta Naresh Nandhakumar

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      Watershed morphometric analysis is important for controlling floods and planning restoration actions. The present study is focused on the identification of suitable sites for locating water harvesting structures using morphometric analysis and multi-criteria based decision support system. The Hathmati watershed of river Hathmati at Idar taluka, Sabarkantha district, Gujarat is experiencing excessive runoff and soil erosion due to high intensity rainfall. Earth observation dataset such as Digital Elevation Model and Geographic Information System are used in this study to determine the quantitative description of the basin geometry. Several morphometric parameters such as stream length, elongation ratio, bifurcation ratio, drainage density, stream frequency, texture ratio, form factor, circularity ratio, and compactness coefficient are taken into account for prioritization of Hathmati watershed. The overall analysis reveals that Hathmati comprises of 13 mini-watersheds out of which, the watershed number 2 is of utmost priority because it has the highest degradation possibilities. The final results are used to locate the sites suitable for water harvesting structures using geo-visualization technique. After all the analyses, the best possibilities of check dams in the mini-watersheds that can be used for soil and water conservation in the watershed are presented.

    • Monitoring implementation of desertification combating plan using geomatics – A case study, districts Dhar and Jhabua, Madhya Pradesh

      Dasgupta Arunima P S Dhinwa A S Rajawat

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      The world’s drylands are subject to desertification as a result of extended droughts, climate change, and human activities. Development in drylands depends on addressing degradation of the ecosystem, main-streaming sustainable natural resources management, and building upon the existing adaptive capacities of communities and institutions. In this regard, recent scientific results aimed to promote sustainable development through action plans for combating desertification. In India, under the Integrated Mission for Sustainable Development (IMSD) programme, remote sensing based integrated land and water resource studies were carried out with an objective to generate locale specific action plans for sustainable development of a region. A specific study was carried out, in districts of Jhabua and Dhar, in Madhya Pradesh using Composite Land Development Sites (CLDS) approach for forest and wasteland development and soil and water conservation. Various treatments were suggested and implemented in 1995. The present study was carried out with an objective to monitor the positive impacts of combating plan implementation through visual interpretation and NDVI analysis of temporal images of LISS III data, since 1991 to 2013. The study reveals that there is substantial increase in the area of irrigated agricultural land with increase in number of check dams along with the stream channels.

    • Detection of snow melt and freezing in Himalaya using OSCAT data

      Rajashree V Bothale P V N Rao C B S Dutt V K Dadhwal

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      A study of the snow cover melt and freeze using Ku band Oceansat scatterometer (OSCAT) HH polarised backscatter coefficient (𝜎0HH) for 2011 and 2012 is reported for the Himalayas, which contain the world’s largest reserve of ice and snow outside polar regions. The analysis shows spatial and temporal inter-annual variations in the onset of melt/freeze across four regions (Upper Himalaya, Western Himalaya, Central Himalaya, and Eastern Himalaya), nine elevation bands and four aspect zones. A threshold based on temperature–𝜎0HH relation and average 𝜎0HH for the months January–March was used for melt/freeze detection. When the three consecutive images (6 days) satisfied the threshold, the day of first image was selected as melt onset/freeze day. The average melt onset dates were found to be March 11 ± 11 days for Eastern Himalaya, April 3 ± 18 days for Central Himalaya, April 16 ± 27 days for Western Himalaya, and May 12 ± 18 days for Upper Himalaya. Similarly average freeze onset dates were found to be August 23 ± 27 days for Eastern Himalaya, September 08 ± 24 days for Central Himalaya, August 27 ± 11 days for Western Himalaya, and September 13 ± 11 days for Upper Himalaya. All the zones experienced the melt onset earlier by around 20 days in 2011 at elevation above 5000 m. All the zones experienced freeze earlier in 2012, with onset being 18, 19, 11, and 21 days earlier in Eastern, Central, Western, and Upper Himalaya, respectively.

    • Characteristics of water isotopes and hydrograph separation during the spring flood period in Yushugou River basin, Eastern Tianshans, China

      Xiaoyan Wang Zhongqin Li Edwards Ross Ruozihan Tayier Ping Zhou

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      Many of the river basins in northwest China receive water from melting glaciers and snow in addition to groundwater. This region has experienced a significant change in glacier and snowpack volume over the past decade altering hydrology. Quantifying changes in water resources is vital for developing sustainable strategies in the region. During 2013, a water-isotope source apportionment study was conducted during the spring flood in the Yushugou River basin, northwestern China. The study found significant differences in water isotopes between river water, snowmelt water, and groundwater. During the study period, the isotopic composition of groundwater remained relatively stable. This stability suggests that the groundwater recharge rate has not been significantly impacted by recent hydro-climatic variability. The river water flow rate and water 𝛿18O displayed an inverse relationship. This relationship is indicative of snowmelt water injection. The relative contribution of the two sources was estimated using a two-component isotope hydrograph separation. The contribution of snowmelt water and groundwater to Yushugou River were $\sim$63% and $\sim$37%, respectively. From the study, we conclude that snowmelt water is the dominant water source to the basin during the spring melt period.

    • Evaluation of aquifer protective capacity of overburden unit and soil corrosivity in Makurdi, Benue state, Nigeria, using electrical resistivity method

      Daniel N Obiora Adeolu E Ajala Johnson C Ibuot

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      This paper presents result of 30 vertical electrical soundings carried out in Makurdi, Benue state capital, north–central Nigeria to evaluate aquifer protective capacity and soil corrosivity of overburden units in the study area. This was done using the Schlumberger electrode array to obtain the data and was modelled using computer iteration (Winresist software). The field data gives a resolution with 3–4 geoelectric layers and the observed frequencies in curve types include: 30% of KQ, 16.67% of QH, 6.67% of AA and K, 3.33% of HA, Q and A, 10% of H, KH and HK. Using the longitudinal unit conductance (S), the protective capacities of the study area were classified as 36.67% weak, 10% poor, 40% moderate, and 13.33% as good. The corrosivity ratings of the study area show that 10% is strongly corrosive, 23% moderately corrosive, 37% slightly corrosive, and 30% noncorrosive The results reasonably provide information on areas where industries can be sited and iron pipes can be laid in order to safeguard the hydrological setting for resident’s safety in the study area. Regions with moderate/good protective capacity are good sites for locating boreholes.

    • Investigation of vertical mass changes in the south of Izmir (Turkey) by monitoring microgravity and GPS/GNSS methods

      Oya Pamukçu Tolga Gönenç Ayça Çirmik Petek Sindirgi İlknur Kaftan Özer Akdemir

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      The monitoring of gravity changes in a region enables the investigation of regional structural elements depending upon the changes in load compensation. This method, preferred in recent years, has yielded good results from different parts of the world for determination of the deformation at fields. With the addition of GPS/GNSS monitoring to microgravity studies, the mass changes within the crust in vertical directional movements of a region can be estimated. During GPS/GNSS monitoring and microgravity studies, it was found that the behaviour of vertical directions of Izmir and the surrounding areas, indicate an active tectonic regime and high seismic activity, especially since 2000. As a result, regions considered to have a mass change in vertical direction were determined by 3-year measurements and it was found that they were consistently highly seismic.

    • CSAMT investigations of the Caferbeyli (Manisa/Turkey) geothermal area

      Sinem Aykaç Emre Timur Coşkun Sari Çagri Çaylak

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      Western Turkey is one of the most remarkable regions of very active continental extension in the world. The most significant structures of this region are Alaşehir, Gediz, and Büyük Menderes Grabens. Geothermal activity around city of Manisa in Gediz Graben has been investigated by many researchers and many geothermal boreholes were drilled in order to produce electricity and for heating purposes. The Caferbeyli geothermal area is on the southern side of the Gediz Graben just west of Salihli, Manisa, Turkey. According to rising demand on thermal water around Salihli, geophysical studies were performed using the Controlled Source Audio Magnetotellurics (CSAMT) measurements near the area of Cafer-beyli, and they were interpreted by the two-dimensional modelling. Vertical and horizontal resistivity sections were mapped, and it was determined that a low-resistivity layer exists in the SW part of the survey area. As a result of the studies in the area, the boundaries of the low-resistivity layer were mapped and a test drilling was recommended.

    • Influence of rigid boundary on the propagation of torsional surface wave in an inhomogeneous layer

      Shishir Gupta Rehena Sultana Santimoy Kundu

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      The present work illustrates a theoretical study on the effect of rigid boundary for the propagation of torsional surface wave in an inhomogeneous crustal layer over an inhomogeneous half space. It is believed that the inhomogeneity in the half space arises due to hyperbolic variation in shear modulus and density whereas the layer has linear variation in shear modulus and density. The dispersion equation has been obtained in a closed form by using Whittaker’s function, which shows the variation of phase velocity with corresponding wave number. Numerical results show the dispersion equations, which are discussed and presented by means of graphs. Results in some special cases are also compared with existing solutions available from analytical methods, which show a close resemblance. It is also observed that, for a layer over a homogeneous half space, the velocity of torsional waves does not coincide with that of Love waves in the presence of the rigid boundary, whereas it does at the free boundary. Graphical user interface (GUI) software has been developed using MATLAB 7.5 to generalize the effect of various parameter discussed.

    • Evolution process of the Late Silurian–Late Devonian tectonic environment in Qimantagh in the western portion of east Kunlun, China: Evidence from the geochronology and geochemistry of granitoids

      Nana Hao Wanming Yuan Aikui Zhang Yunlei Feng Jianhui Cao Xiaoning Chen Xueqin Cheng Xuanxue Mo

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      The East Kunlun Orogenic Belt has undergone a composite orogenic process consisting of multiple orogenic cycles and involving many types of magmatic rocks spread over the whole district. However, due to bad natural geographical conditions and complex superimposed orogenic processes, most of the Caledonian orogenic traces were modified by the late tectonic uplift and denudation, so these rocks are poorly studied. Multiperiodic magmatic activity during the Late Silurian (approximately 420 Ma)–Late Devonian (approximately 380 Ma) exists in the Qimantagh area. We obtained 5 zircon U–Pb ages from the Late Silurian–Late Devonian granitoids in the Qimantagh area. Those ages are 420.6 ± 2.6 Ma(Nalingguole biotite monzogranite), 421.2 ± 1.9 Ma (Wulanwuzhuer potassium granite), 403.7 ± 2.9 Ma (Yemaquan granodiorite), 391.3 ± 3.2 Ma (Qunli granite porphyry), and 380.52 ± 0.92 Ma (Kayakedengtage granodiorite). These granitoids belong to the sub-alkaline, high-K calc-alkaline, metaluminous or weakly or strongly peraluminous series. The rocks are right oblique types, having overall relative LREE enrichment and HREE depletion, though rocks from different times may exhibit different degrees of Eu anomalies or overall moderate Eu depletion. The rocks are rich in large ion lithophile elements (LILE), such as Rb, Th, and K, and high field strength elements (HFSE), such as Zr and Hf, and are depleted in Ba, Nb, Ta, Sr, P, Eu, and Ti. The rocks have complex composition sources. The Late Silurian granitoids are mainly crust-derived. Most of the Devonian granitoids are crust-mantle mixed-source and only some parts of them are crust-derived, especially the Middle Devonian granitoids. Those mid-acidic and acidic intrusive rocks are formed in a post-collision tectonic setting, lithosphere delamination may have occurred in the Early Devonian (407 Ma), and the study area subsequently experienced an underplating of the mantle-derived magma at least until the Late Devonian (380 Ma).

    • High grade metamorphism in the Bundelkhand massif and its implications on Mesoarchean crustal evolution in central India

      S P Singh S B Dwivedi

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      The Bundelkhand Gneissic Complex (BnGC) in the central part of the Bundelkhand massif preserves a supracrustal unit which includes pelitic (garnet–cordierite–sillimanite gneiss, garnet–sillimanite gneiss, biotite gneiss and garnet–biotite gneiss) and mafic (hornblende–biotite gneiss and garnetiferous amphibolite) rocks. Granulite facies metamorphism of the complex initiated with breaking down of biotite to produce garnet and cordierite in the pelitic gneisses. Geothermobarometric calculations indicate metamorphic conditions of 720°C/6.2 kbar, followed by a retrograde (687°C/4.9 kbar) to very late retro-grade stages of metamorphism (579°C/4.4 kbar) which is supported by the formation of late cordierite around garnet. The P–T conditions and textural relations of the garnet–cordierite-bearing gneiss suggest a retrograde cooling path of metamorphism.

    • Paragenesis of Cr-rich muscovite and chlorite in green-mica quartzites of Saigaon–Palasgaon area, Western Bastar Craton, India

      K R Randive M M Korakoppa S V Muley A M Varade H W Khandare S G Lanjewar R R Tiwari K K Aradhi

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      Green mica (fuchsite or chromian-muscovite) is reported worldwide in the Archaean metasedimentary rocks, especially quartzites. They are generally associated with a suite of heavy minerals and a range of phyllosilicates. We report the occurrence of green-mica quartzites in the Saigaon–Palasgaon area within Bastar Craton in central India. Mineralogical study has shown that there are two types of muscovites; the chromium-containing muscovite (Cr2O3 0.84–1.84%) and muscovite (Cr2O3 0.00–0.22%). Chlorites are chromium-containing chlorites (Cr2O3 3.66–5.39%) and low-chromium-containing chlorites (Cr2O3 0.56–2.62%), and as such represent ripidolite–brunsvigite varieties. Back scattered electron images and EPMA data has revealed that chlorite occurs in two forms, viz., parallel to subparallel stacks in the form of intergrowth with muscovite and independent crystals within the matrix. The present study indicates that the replacement of chromium-containing chlorite by chromium-containing muscovite is found to be due to increasing grade of metamorphism of chromium-rich sediments. However, the absence of significant compositional gap between aforementioned varieties indicates disparate substitution of cations, especially chromium, within matrix chlorites. The chromium-containing muscovite and muscovite are two separate varieties having distinct paragenesis.

    • Lagerstroemia L. from the middle Miocene Siwalik deposits, northern India: Implication for Cenozoic range shifts of the genus and the family Lythraceae

      Gaurav Srivastava Rajan Gaur R C Mehrotra

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      Fossil leaves of Lagerstroemia (Lythraceae) are described from the Siwalik deposits (middle Miocene) of Kathgodam, Uttarakhand, India. The fossil records of the Lythraceae indicate its worldwide distribution in the Cenozoic. The family had its widest distribution during the Miocene but became less widespread during the Pliocene, followed by range expansion during the Quaternary. The present leaf fossil, along with the previous fossil records of Lagerstroemia, indicates that the genus followed the same pattern of expansion and retraction as the entire family Lythraceae suggesting that both the genus and the family adapted in similar ways. The fossil plant assemblage from the Lower Siwalik deposits indicates warm and humid climate with plenty of rainfall in the region during the depositional period.

    • The role of impact and radiogenic heating in the early thermal evolution of Mars

      S Sahijpal G K Bhatia

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      The planetary differentiation models of Mars are proposed that take into account core–mantle and coremantle–crust differentiation. The numerical simulations are presented for the early thermal evolution of Mars spanning up to the initial 25 million years (Ma) of the early solar system, probably for the first time, by taking into account the radiogenic heating due to the short-lived nuclides, 26Al and 60Fe. The influence of impact heating during the accretion of Mars is also incorporated in the simulations. The early accretion of Mars would necessitate a substantial role played by the short-lived nuclides in its heating. 26Al along with impact heating could have provided sufficient thermal energy to the entire body to substantially melt and trigger planetary scale differentiation. This is contrary to the thermal models based exclusively on the impact heating that could not produce widespread melting and planetary differentiation. The early onset of the accretion of Mars perhaps within the initial $\sim$1.5 Ma in the early solar system could have resulted in substantial differentiation of Mars, provided, it accreted over the timescale of $\sim$1 Ma. This seems to be consistent with the chronological records of the Martian meteorites.

    • Survey of land subsidence – case study: The land subsidence formation in artificial recharge ponds at South Hamadan Power Plant, northwest of Iran

      Ahmad Khorsandi Aghai

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      The artificial recharge is a technique of aquifer conservation for land subsidence. But in this article, the phenomenon of land subsidence and the resulting cracks and fissures at the study area are formed in recharge ponds. This is a new phenomenon and in this research the geometrical properties of the fissures of recharge ponds are measured. The results reveal the existence of fine layers in the geology of the aquifer, which are displaced in the long run as the consequence of groundwater overdraft. At the site of the artificial recharge subject of this research, the difference between the quality of recharge water and the aquifer and their interaction have intensified the instability and the movement of the fine sediments. In addition, the neglect of hydraulic principles of the groundwater during the construction and operation of the recharge wells has resulted in turbulent and speed flows, intensified displacement of fine sediments and ultimately the localized subsidence at the site of the plan.

    • Climate change and its role in forecasting energy demand in buildings: A case study of Douala City, Cameroon

      Modeste Kameni Nematchoua Gh R Roshan René Tchinda T Nasrabadi Paola Ricciardi

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      The foremost role of a building is to assure the comfort of its occupants. The thermal comfort of a building depends on the outdoor climate and requires a demand in energy for heating and cooling. In this paper, demand of energy (heating/cooling) in the buildings is discussed in Douala, Cameroon. Daily data of the last 40 years coming from five weather stations of Cameroon have been studied. Some forecasts have been carried out with 14 GCM models, associated to three future climate scenarios B1, A2, and A1B. However, only INCM3 of General Circulation Model (GCM) and A2 scenario was used. Energy demand in buildings is valued by HDD (heating degree day) and CDD (cooling degree day) indices. Obtained results show that the temperature evolves more quickly in dry season than in rainy season in Douala. Climate rise indicates an increasing demand of energy in the buildings for cooling. Global Douala heating shows a definite effect on outdoor comfort. From 2045 to 2075, the demand of energy for cooling will be superior to 50%. The total demand in energy for heating in the buildings is estimated to be 67.882 kcal from 1970 to 2000 and will be around 67.774 kcal from 2013 to 2043.

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