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61.
62.
S Pal S Manna A Aich B Chattopadhyay S K Mukhopadhyay 《Journal of Earth System Science》2014,123(4):729-740
The present investigation was made to characterize spatial and temporal variations in soil properties and to evaluate possible differences that could be dependent on the tannery effluent discharges, municipal sewage discharges, vegetation cover, soil settlement rate, crop rotation, etc. Soil total organic matter (TOM), cations like, Sodium (Na), Ammonium (NH4), Potassium (K), Calcium (Ca) and Magnesium (Mg) contents in the bank soils and bottom sediments were recorded from seven different characteristic sites in East Kolkata wetland ecosystem, a Ramsar site (Ramsar site No. 1208). The profile maps were constructed by geostatistical methods to describe the spatial distribution as well as temporal variations of all the factors to identify the influences of composite wastewaters. The work was initiated to identify causes and consequences of the waste dumping in the concerned region for the past hundred years and thereby to suggest necessary precautionary measures to prevent further loss of soil quality. 相似文献
63.
64.
Ocean Dynamics - Since the 2004 Indian Ocean tsunami and particularly after the 2011 Tohuku tsunami, there has been a significant increase of computer simulation using real-time data; however,... 相似文献
65.
The efficiency of low cost citrus peels as biosorbents for removal of cadmium ions from aqueous solution was investigated in a fixed bed column, a process that could be applied to treat industrial wastewaters similar to commonly used ion exchange columns. Effluent concentration versus time profiles (i.e., breakthrough curves) were experimentally determined in a laboratory‐scale packed bed column for varying operational parameters such as flow rate (2, 9, and 15.5 mL/min), influent cadmium concentration (5, 10, and 15 mg/L), and bed height (24, 48, and 72 cm) at pH 5.5. Column operation was most efficient for empty bed contact times of at least 10 min, which were apparently necessary for mass transfer. While the sorption capacity was largely unaffected by operational variables, the Thomas (Th) rate constant increased with the flow rate, and slightly decreased with increasing column length. Three widely used semi‐mechanistic models (Th, Bohart–Adams, and Yoon–Nelson) were shown to be equivalent and the generalized model was compared with a two‐parameter empirical model (dose‐response). The latter was found to be able to better simulate the breakthrough curve in the region of breakthrough and saturation. 相似文献
66.
Abhijit Basu 《Meteoritics & planetary science》1976,11(3):207-216
A single fragment from an Apollo 16 soil appears to be a soil agglutinate that has experienced thermal metamorphism. Its texture is similar to that observed in many of the samples of recrystallized polymict breccias collected in the lunar highlands. Debris blankets, consisting largely of mineral and lithic clasts and derived from highland bedrock by major impacts, are less likely than agglutinate-rich soil from the highland megaregolith to be the progenitor of this class of recrystallized rocks. 相似文献
67.
Anant Parekh Abhijit Sarkar M. Ravichandran 《Journal of the Indian Society of Remote Sensing》2005,33(1):121-126
Multi-channel Scanning Microwave Radiometer (MSMR) onboard 1RS P4 (Oceansat I) measured Brightness Temperature data of the
different bands are found sensitive to the surface and the overlying atmosphere to different degrees. A judicious combination
of multi-channel data can provide such oceanic/atmospheric parameters as surface wind speed, sea surface temperature, water
vapour in the marine atmosphere, etc. This paper highlights results obtained in relation to surface wind speed. Co-location
and concurrence of several ocean data buoys in the Arabian Sea with MSMR observations allowed empirical construction of D-matrix
coefficients for surface wind speed. With both MSMR and the Arabian Sea buoys functioning for the period of one and a half
year (June, 1999 to December, 2000) without interruptions provided a large database. All channels are found to exhibit moderate
sensitivity to surface wind speed. MSMR data in the immediate vicinity (within 150 km) of the buoy locations and within a
time window of one hour were used. A multi-channel linear equation for surface wind speed was subsequently derived. The equation
was subjected to tests with independent data set for the period January - June 2001 over the Arabian Sea and found to be moderately
accurate. The empirical equation is expected to be useful for regional applications over the Arabian Sea and over regions
closer to west coasts, which might have been flagged out in the operational geophysical data stream. An interesting subset
of data revealed the wind signatures of the May 2001 cyclone in the Arabian Sea. 相似文献
68.
C M Kishtawal P K Pal M S Narayanan S K Manna O P Sharma Sangeeta Agarwal H C Upadhyaya 《Journal of Earth System Science》1993,102(4):507-519
The impact of moisture anomalies on the circulation of the south-west Indian monsoon has been studied with a general circulation model. Newtonian relaxation is adopted to subject the model atmosphere under sustained moisture anomalies. The impact of negative anomalies of moisture was seen as a divergent circulation anomaly, while the positive anomaly was a stronger convergent anomaly. Although the humidity fields display a resilient behaviour, and relax back to normal patterns 1–2 days after the forcing terms in humidity are withdrawn, the circulation anomalies created by the moisture variation keeps growing. A feedback between positive moisture anomalies and low level convergence exists, which is terminated in the absence of external forcings. 相似文献
69.
The problem of selecting the optimum operating frequency of a scatterometer, used for remote sensing of sea surface wind speed
has been addressed by applying the criteria of maximum sensitivity of backscattering coefficient to wind speed as well as
its correlation with wind speed. The backscattering coefficient values for sea surface were computed by the two-scale scattering
theory. To compute the atmospheric transmittance, 753 clear sky atmospheres over Indian Ocean were used. While the correlation
coefficient was uniform (0.94) throughout the frequency range of 1 to 30GHz, only frequencies above 5GHz were found sensitive
enough to yield a wind speed accuracy of ±2msec−1 and better, the accuracy improving with frequency. 相似文献
70.
The paper deals with the relationship between the sea surface wind speed (U) and the backscattering coefficient (σ0) for microwave frequencies and quasi specular range of angles. Valenzuela’s effective reflection coefficient based on the theory of scattering of electromagnetic waves from rought dielectric surfaces has been introduced in the expression of backscattering coefficient and the final result compared with the σ0-U relationship derived fromSEASAT scatterometer and concurrent sea truth data. 相似文献