Mapping groundwater recharge potential using GIS approach in Darwha block

Groundwater is the most important source of water in meeting irrigation, drinking, and other needs in India. The assessment of the potential zone for its recharge is critical for sustainable usage, quality management, and food security. This study reports alternative mapping of the groundwater recharge potential of a selected block by including large-scale soil data. Thematic layers of soil, geomorphology, slope, land use land cover, topographical wetness index, and drainage density of Darwha block (District Yavatmal, Maharashtra, India) were generated and integrated in a geographic information system environment. The topographic maps, thematic maps, field data, and satellite image were processed, classified, and weighted using analytical hierarchical process for their contribution to groundwater recharge. The layers were integrated by weighted linear combination method in the GIS environment to generate four groundwater potential zones viz., “poor,” “poor to moderate,” “moderate to high,” and “high.” Based on the generated groundwater potential map, about 9830 ha (12%) of the study area was categorized as high potential for recharge, 25,558 ha (31%) as poor to moderate, 33,398 ha (40%) as moderate to high, and 12,565 ha (15%) as poor potential zone. The zonation corresponds well with the field data on greater well density (0.22/ha) and irrigated crop area (27%) in the high potential zone as against 0.02 wells/ha and only 6% irrigated area in the poor zone. The map is recommended for use in regulating groundwater development decisions and judicious expenditure on drilling new wells by farmers and the state authorities.     

Vegetation damage assessment due to Hudhud cyclone based on NDVI using Landsat-8 satellite imagery

Developing nations are abandoned against tropical cyclones because of climatic changeability; the atmosphere is probably going to expand the recurrence and extent of some outrageous climate and calamity occasions. Urban areas and towns arranged along the coastline front belt in Visakhapatnam region experienced serious harm because of Hudhud cyclone, which happened on October 12, 2014. The fundamental motivation behind this exploration was to distinguish the vegetation damage in Visakhapatnam and neighbouring towns. In this analysis, Landsat-8 satellite datasets procured prior and then afterward the cyclone have been utilized; image processing techniques have been completed to evaluate the progressions of pre- and post-disaster condition. Vegetation index strategy was utilized to assess the damage to vegetation. Arrangement results and land utilize land cover change investigation demonstrate that 13.25% of agriculture Kharif and 31.1% of vegetation was damaged. Normalized difference vegetation index (NDVI) maps were produced for the previously, then after the cyclone circumstance, and vegetation biomass damage was evaluated in Visakhapatnam and Bhimunipatanam. General loss of vegetation in both the spots was 30.67 and 43.37 km². The result of this review can be utilized by decision makers for the post-disaster support for rebuilding of influenced regions.     

Comparison of AMSR-2 wind speed and sea surface temperature with moored buoy observations over the Northern Indian Ocean

The Northern Indian Ocean (NIO) is unique due to seasonal reversal of wind patterns, the formation of vortices and eddies which make satellite observations arduous. The veracity of sea surface wind (SSW) and sea surface temperature (SST) products of sun-synchronous AMSR-2 satellite are compared with high-temporal moored buoy observations over the NIO. The two year-long (2013–2014) comparisons reveal that the root-mean-square-error (RMSE) of AMSR-2 SST and SSW is \(<0.4{^{\circ }}\hbox {C}\) and \(<1.5\hbox { ms}^{-1}\), respectively, which are within the error range prescribed for the AMSR-2 satellite (\(\pm 0.8{^{\circ }}\hbox {C}\), \(\pm 1.5\hbox { ms}^{-1})\). The SST–wind relation is analyzed using data both from the buoy and satellite. As a result, the low-SST is associated with low-wind condition (positive slope) in the northern part of the Bay of Bengal (BoB), while low SST values are associated with high wind conditions (negative slope) over the southern BoB. Moreover, the AMSR-2 displayed larger slope for SST–wind relation and could be mainly due to overestimation of SST and underestimation of wind as compared to the buoy. The AMSR-2 SSW exhibited higher error during post-monsoon followed by monsoon season and could be attributed to the high wind conditions associated with intense oceanic vortices. The study suggests that the AMSR-2 products are reliable and can be used in tropical air–sea interactions, meso-scale features, and weather and climate studies.     

Influence of pH on Sporulation,Spore Germination and Germling Survival in Blue-green Algae

An investigation is made on the influence of the pH-value in the range of pH = 4.5 to 11.0 on sporulation, germination and germling development of Anabaena fertilissima and Anabaenopsis arnoldii, isolated from the Sambhar Salt Lake, Rajasthan. Maximum rates of germination were obtained with Anabaena at pH = 7.0… 10.5, with Anabaenopsis at pH = 7.0 to 8.5. With both species, sporulation occurs in the same pH-ranges, Anabaena dying without sporulation in the range of pH = 5.5… 6.5 and above pH = 10.5 and Anabaenopsis surviving without sporulation above pH = 9.5. With Anabaena the germling growth steadily increases from pH = 7 to 10.5, whereas Anabaenopsis shows a maximum at pH = 7 and at any other pH-value growth is considerably lower. Moreover, spore germination is bound to an exchange of the medium. In agreement with these experimental findings concerning the cultures, from July to February Anabaenopsis occurs in the Sambhar Lake as a vegetative form with a partial mass development, and from March to June it survives as a spore. Anabaena, however, has only a short vegetative phase in June, and it survives the remaining part of the year as a spore. Thus, the fast germination and sporulation in the range of higher alkalinity is the ecological strategy for Anabaena to resist the competition offered by Anabaenopsis.     

A technique to assess dispersion

A technique to arrive at conditions congenial to maintaining a stable suspension of fine particles has been described. The technique involves continuous monitoring of apparent loss of weight of a body suspended in settling slurries. Such a technique is useful in fixing the best conditions for gravity separation of fine particles involving Bartles-Mozley concentrators or hydrocyclones.     

List of Forthcoming Papers

Other Index

List of Forthcoming Papers     

Shear flow instabilities in the Earth’s magnetotail

Shear flow instability is studied in the Earth’s magnetotail by treating plasma as compressible. A dispersion relation is derived from the linearized MHD equations using the oscillating boundary conditions at the inner central plasma sheet/outer central plasma sheet (OCPS) interface and OCPS/plasma-sheet boundary layer (PSBL) interface, whereas the surface-mode boundary condition is used at the PSBL/lobe interface. The growth rates and the real frequencies are obtained numerically for near-Earth (\midX\mid\sim10-15 R_E) and far-Earth (\midX\mid\sim100 R_E) magnetotail parameters. The periods and wavelengths of excited modes depend sensitively on the value of plasma-sheet half thickness, L, which is taken as L=5 R_E for quiet time and L=1 R_E for disturbed time. The plasma-sheet region is found to be stable for constant plasma flows unless M_A3>1.25, where M_A3 is the Alfvén Mach number in PSBL. For near-Earth magnetotail, the excited oscillations have periods of 2–20 min (quiet time) and 0.5-4 min (disturbed time) with typical transverse wavelengths of 2–30 R_E and 0.5-6.5 R_E, respectively; whereas for distant magnetotail, the analysis predicts the oscillation periods of \sim8-80 min for quiet periods and 2–16 min for disturbed periods.     

Formation of blanketing sporadic E-layers at the magnetic equator due to horizontal wind shears

A careful survey of quarter-hourly ionograms for the year 1969 has shown that blanketing layer type ionization irregularities occur on many occasions in the E-region of the ionosphere over Trivandrum (dip ～ 0.6°S). It is shown that horizontal shears of horizontal neutral winds are the most likely sources of such layer type irregularities at the magnetic equator. The horizontal wind shears of required magnitude are shown to be provided by internal gravity waves of short period. The rarity of E_s-layer occurrence is attributed to the stringent requirements on the amplitude and wave vector orientation of the relevant gravity waves generating the E_s-layers.