Wind speed prediction using statistical regression and neural network

Prediction of wind speed in the atmospheric boundary layer is important for wind energy assessment, satellite launching and aviation, etc. There are a few techniques available for wind speed prediction, which require a minimum number of input parameters. Four different statistical techniques, viz., curve fitting, Auto Regressive Integrated Moving Average Model (ARIMA), extrapolation with periodic function and Artificial Neural Networks (ANN) are employed to predict wind speed. These methods require wind speeds of previous hours as input. It has been found that wind speed can be predicted with a reasonable degree of accuracy using two methods, viz., extrapolation using periodic curve fitting and ANN and the other two methods are not very useful.     

Biostratigraphy and depositional environment of the Miocene limestone bed of Baripada,Mayurbhanj district,Odisha: Foraminiferal,sedimentological and bulk organic geochemical evidences

Baripada Marine Beds (BMB) have been studied extensively in terms of its mega fossil content. However, not much has been discussed about the foraminiferal content and the organic matter assemblage in these beds. The fossiliferous sequence of BMB consists of sandstone, shale and limestone units. The present study is persued on the limestone unit of BMB. Foraminiferal, thin section and rock-eval pyrolysis studies were performed on the 33 surface samples collected from five sections of Jamdapal and Mukurmatia region along the Budhabalang river bank. Foraminifera are less abundant in the samples of Jamdapal, whereas Mukurmatia is comparatively rich. First appearance datum of Globorotalia menardii[ranges since middle Miocene (12.6 Ma); FAD at planktic foraminiferal zone N12] and last appearance datum of Neogloboquadrina continuosa [ranges between early Miocene (23.2 Ma) to late Miocene (8.3 Ma); FAD at planktic foraminiferal zone N4B and LAD at N16] together suggest that the limestone unit was deposited in between 12.6 to 8.3 Ma within the upper Miocene. Also, the association of shallow water benthic foraminifera (Species of Ammonia, Asterorotalia, Bolivina, Buliminella, Cibicides, Challengerella, Criboelphidium, Cribononion, Elphidium, Hanzawaia, Nonionella) and planktic foraminifera (Globigerina falcoensis, Globigerina woodi, Globorotalia menardii, Neogloboquadrina continuosa) together with oyster bank and shark teeth suggest deposition of limestone within well oxygenated, tropical, shallow water, open marine condition (within 40m water depth). Lithological and thin section studies together with global sea level fluctuation history advocate that upper Miocene marine transgression promoted the formation of this unit. Bulk organic geochemical data obtained by the rock-eval pyrolysis studies on selected samples indicate a low total organic carbon (TOC), with low hydrogen index (HI), high oxygen index (OI). The organic facies is characterised by type-IV kerogen with major contribution from near shore terrestrial plants. This also suggests deposition in shallow, oxygenated environments that did not promote significant accumulation and preservation of organic content in sediments.     

Geochemical characterization of adsorbed light gaseous alkanes in near surface soils of the eastern Ganga basin for hydrocarbon prospecting

This study aims to assess the hydrocarbon potential of Ganga basin utilizing the near surface geochemical prospecting techniques. It is based on the concept that the light gaseous hydrocarbons from the oil and gas reservoirs reach the surface through micro seepage, gets adsorbed to soil matrix and leave their signatures in soils and sediments, which can be quantified. The study showed an increased occurrence of methane (C₁), ethane (C₂) and propane (C₃) in the soil samples. The concentrations of light gaseous hydrocarbons determined by Gas Chromatograph ranged (in ppb) as follows, C₁: 0–519, C₂: 0–7 and C₃: 0–2. The carbon isotopic (VPDB) values of methane varied between ?52.2 to ?27.1‰, indicating thermogenic origin of the desorbed hydrocarbons. High concentrations of hydrocarbon were found to be characteristic of the Muzaffarpur region and the Gandak depression in the basin, signifying the migration of light hydrocarbon gases from subsurface to the surface and the area’s potential for hydrocarbon resources.     

Aerodynamic drag coefficient and roughness length for three seasons over a tropical western Indian station

Land Surface Processes Experiment (LASPEX) was conducted over semi-arid region of western India in 1997. As a part of this program, wind and temperature observations were taken using slow as well as fast response sensors over a semi-arid station Anand (22°35′N, 72°55′E) situated in Gujarat state of India. Turbulent parameters such as drag coefficient and sensible heat flux were estimated using eddy correlation method and aerodynamic roughness length was estimated using wind profiles. The analysis has been carried out for the data representing summer, monsoon and winter seasons. It was found that the wind speed does not exceed 5 ms^− 1 during the observational period considered in this study. Relationship of aerodynamic drag coefficient and roughness length with wind speed and stability has been investigated. Aerodynamic roughness length was greater in the stable conditions when the wind speed was low and it reduced drastically during convective conditions. The resulting values of aerodynamic roughness length and drag coefficient for the monsoon period agree well with values reported in literature over Indian subcontinent for homogeneous grass covered surfaces.     

Evaluation of Noah-LSM for soil hydrology parameters in the Indian summer monsoon conditions

The micrometeorological observations, collected over a station in Ranchi (23°45′N, 85°30′E) which is under the monsoon trough region of India, were used in the Noah-LSM (NCEP, OSU, Air Force and Office of Hydrology Land Surface Model) to investigate the model performance in wet (2009 and 2011) and dry (2010) conditions during the south-west summer monsoon season. With this analysis, it is seen that the Noah-LSM has simulated the diurnal cycle of heat fluxes (sensible and ground) reasonably. The simulated heat fluxes were compared with its direct measurements by sonic anemometer and soil heat flux plate. The net radiation and sensible heat flux are simulated well by the model, but the simulation of ground heat flux was found to be poor in both dry as well as wet conditions. The soil temperature simulations were also found to be poor in 0–5- and 5–10-cm layers compared to other deeper layers. The observations were also correlated with the Modern Era Retrospective-analysis for Research and Applications (MERRA) data. The correlation between the observations and ground heat flux was better in MERRA dataset than that of the Noah-LSM simulation.     

Implications of new $$^{40}\hbox {Ar}/^{39}\hbox {Ar}$$ age of Mallapur Intrusives on the chronology and evolution of the Kaladgi Basin,Dharwar Craton,India

The Kaladgi Basin on the northern edge of the Dharwar craton has characters diverse from the other epicratonic Purana basins of Peninsular India. Sedimentological studies in the basin have established the presence of three cycles of flooding separated by an event of intra-basinal deformation accompanied by low grade incipient metamorphism. The overall structural configuration of the basin indicates its development by supracrustal extension accompanied by shearing in a trans-tensional regime during the Mesoproterozoic. This was followed by sagging that yielded Neoproterozoic sedimentation in a successor nested basin. \(^{40}\)Ar/\(^{39}\)Ar dating of an intrusive mafic dyke along the axial plane of a fold has yielded a plateau age of \(1154{\pm }4\,\hbox {Ma}\). This helps constraint the age of the various events during the evolution of this basin.     

Probabilistic seismic hazard at the archaeological site of Gol Gumbaz in Vijayapura,south India

Probabilistic seismic hazard analysis (PSHA) is carried out for the archaeological site of Vijayapura in south India in order to obtain hazard consistent seismic input ground-motions for seismic risk assessment and design of seismic protection measures for monuments, where warranted. For this purpose the standard Cornell-McGuire approach, based on seismogenic zones with uniformly distributed seismicity is employed. The main features of this study are the usage of an updated and unified seismic catalogue based on moment magnitude, new seismogenic source models and recent ground motion prediction equations (GMPEs) in logic tree framework. Seismic hazard at the site is evaluated for level and rock site condition with 10% and 2% probabilities of exceedance in 50 years, and the corresponding peak ground accelerations (PGAs) are 0.074 and 0.142 g, respectively. In addition, the uniform hazard spectra (UHS) of the site are compared to the Indian code-defined spectrum. Comparisons are also made with results from National Disaster Management Authority (NDMA 2010), in terms of PGA and pseudo spectral accelerations (PSAs) at T = 0.2, 0.5, 1.0 and 1.25 s for 475- and 2475-yr return periods. Results of the present study are in good agreement with the PGA calculated from isoseismal map of the Killari earthquake, \({\hbox {M}}_{\mathrm{w}} = 6.4\) (1993). Disaggregation of PSHA results for the PGA and spectral acceleration (\({\hbox {S}}_{\mathrm{a}}\)) at 0.5 s, displays the controlling scenario earthquake for the study region as low to moderate magnitude with the source being at a short distance from the study site. Deterministic seismic hazard (DSHA) is also carried out by taking into account three scenario earthquakes. The UHS corresponding to 475-yr return period (RP) is used to define the target spectrum and accordingly, the spectrum-compatible natural accelerograms are selected from the suite of recorded accelerograms.     

Patterns and trends in seabird bycatch in the pelagic longline fishery off South Africa

Both foreign and domestic pelagic longline fishing vessels operate in South Africa’s Exclusive Economic Zone and adjacent international waters where they kill hundreds of seabirds each year as bycatch. To update assessments of the impact of the pelagic longline fishery on seabirds off South Africa, information on necropsied seabirds and national fisheries observer bycatch records were summarised for 2006–2013. Foreign-flagged (Asian) vessels had 100% observer coverage throughout the study period, whereas only 6% of the fishing effort by South African-flagged vessels was observed (with no coverage in 2011–2013). Vessels with observers caught seabirds at a rate of 0.132 birds per 1 000 hooks, resulting in an estimated mortality of 2 851 individuals (356 per year) comprising 14 species. Extrapolation of the observed fishing sets to the unobserved fishing sets by the South African domestic longline fleet suggested that approximately 750 additional birds were likely killed during the study period, therefore a combined 450 birds were killed per year. White-chinned petrel Procellaria aequinoctialis was the most frequently killed species (66%), followed by ‘shy-type’ albatrosses Thalassarche cauta/steadi (21%), black-browed albatross T. melanophris (7%), Indian yellow-nosed albatross T. carteri (3%), and Cape gannet Morus capensis (2%). The seabird bycatch rates were lower than in 1998–2005. Nationality of the vessel, time of line-setting, moon phase, year, season, fishing area, and seabird bycatch mitigation measures all influenced seabird mortality. Concurrent with 100% observer coverage, significant reductions in the seabird bycatch rate occurred in the Asian fleet in the latter years of the study, and these rates now approximate the national target (0.05 birds per 1 000 hooks). However, seabird bycatch rates remained high in the South African fleet, where no observers were deployed during 2011–2013, highlighting the need for independent observer programmes in fisheries—a matter of global interest. Suggestions are made as to how seabird bycatch by pelagic longline fisheries off South Africa may be further reduced.     

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography.This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4 m-627.9 m); unit C-GH1 (649.8 m-660.8 m); and unit C-GH2 (663.2 m-666.3 m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate.In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average “plug” intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7 mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude.     

Distribution of phytoplankton in the East China Sea and the southern Yellow Sea in spring in relation to environmental variables and dimethylsulfide compounds

The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors. In the present study, the phytoplankton community, chlorophyll a（Chl a） and their relationships with environmental variables and dimethylsulfide（DMS） and dimethylsulfoniopropionate（DMSP） were investigated in spring 2017（March 24 to April 16） in the East China Sea（26.0°–33.0°N, 120.0°–128.0°E） and southern Yellow Sea（31.0°–36.0°N, 12...