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21.
R. L. Mehta N. Parihar A. Sinha B. P. Shastri M. Chakraborty 《Journal of the Indian Society of Remote Sensing》2014,42(2):439-444
Radar sensors can be used for large-scale vegetation mapping and monitoring using backscattering coefficients in different polarizations and wavelength bands. C-band space borne SAR is widely used for the classification of agricultural crops, but can only perform a limited discrimination of various tree species. This paper presents the results of discrimination between mustard crop and babul plantation (Prosopis sp.) using quad polarisation Radarsat 2 and ALOS PALSAR data. Study area is comprised of dense babul plantation along the canal, mustard crop on one side of the canal and Fallow land near to Ramgarh village of Jaisalmer district. Three bands of Radarsat (HH, HV and VV) acquired during peak mustard crop growth stage were integrated with four polarizations (HH, HV, VH and VV) of ALOS PALSAR acquired when crop cover was absent. Using only Radarsat data Jefferies-Matusita (JM) separability between mustard crop and babul plantation was found to be poor (710). Where as in the seven band combination the separability was observed to be high (1374). Among the different polarizations three layer combination, highest separability was observed using cross polarizations (HV and VH) of L-band with any one of the Radarsat Polarisation (HH/HV/VV). This combination of C- and L-band resulted in easy separation of mustard and babul plantation which was otherwise difficult using only Radarsat data. 相似文献
22.
S. Panigrahy J. S. Parihar N. K. Patel V. K. Dadhwal T. T. Medhavy B. K. Ghose N. Ravi K. C. Pani B. K. Panigrahy V. N. Sridhar R. R. Mohanty S. K. Nanda D. P. Tripathy P. K. Mishra H. P. Bhatt S. R. Oza S. Sudhakar K. S. Sudha P. Kumar N. K. Das 《Journal of the Indian Society of Remote Sensing》1991,19(1):17-26
Rice is one of the most important foodgrains grown in India. Attempts have been made to estimate kharif rice acreage of Orissa state since 1986 using digital remote sensing data from Landsat MSS/TM and/or IRS-1A. Accuracies of the estimates obtained have been evaluated against BES (Bureau of Economics and Statistics) estimate. This paper describes the methodology adopted for rice acreage estimation of Orissa state, the results obtained for three years, i.e. 1986–87, 1988–89 and 1989–90, and their accuracy. 相似文献
23.
S. S. Ray Anil Sood Gargi Das Sushma Panigrahy P. K. Sharma J. S. Parihar 《Journal of the Indian Society of Remote Sensing》2005,33(2):181-188
In this study, an attempt has been made to suggest crop diversification based on soil and weather requirements of different
crops. State level spatial databases of various agro-physical parameters such as rainfall, soil texture, physiography and
problem soil along with the agricultural area derived from remote sensing data were integrated using GIS. A raster based modelling
approach was followed to arrive at suitable zones for practicing different cropping systems. The results showed that the south-western
Punjab is suitable for low water requiring crops such as desi cotton, pearl millet, gram etc., where as north-eastern Punjab
with high rainfall and excess drainage should practice maize based cropping system. Rice can be substituted by maize and other
crops in Central Punjab, where water table is going down fast. Using this approach the area of rice based cropping system
can be reduced from present 24.7 lakh ha to 19.6 lakh ha, thereby reducing the degradation of valuable land and water resources. 相似文献
24.
Nearshore marine environments are influenced by an array of variables that can either be land-derived or of marine origin, and nearshore phytoplankton communities may differ in their taxonomic composition and biomass in response to such variables. The KwaZulu-Natal Bight (hereafter referred to as ‘the bight’) is an oligo-mesotrophic, nearshore oceanic environment, that is influenced by both terrestrial run-off and upwelling. A microphytoplankton survey of the bight conducted over several stations and depths and two seasons was conducted in order to ascertain species composition, abundance and biomass. Microphytoplankton abundance was generally low (a maximum of 180 000 cells l–1 was recorded) but differed considerably between sites and seasons. A total of 99 taxa of mainly Bacillariophyceae and some Dinophyceae, Prymnesiophyceae and Cyanophyceae were identified in the present study. In the central bight, higher abundance and biomass were measured in February (wet season), which may be a possible consequence of terrestrial nutrient inputs. In the northern and southern bight we measured higher abundance and biomass in August (dry season). Upwelling was not detected during the study, but an influence of terrestrial nutrient sources was detected at the coastal stations. Turbid conditions were specific to the site near the Thukela River mouth and possibly influenced abundance, biomass and species composition at this site. Historic data on microphytoplankton composition are scarce, but comparisons with surveys from the 1960s reveal that around 60% of the common diatoms recorded then also occurred in the present study. Small taxa [20–200 µm] dominated the microphytoplankton community. Community composition was fairly uniform throughout the bight in both seasons, dominated in general by Chaetoceros species, and on occasion co-dominated by Thalassionema nitzschioides and Dactyliosolen fragilissimus. 相似文献
25.
26.
Mehul R. Pandya Raghavendra Pratap Singh Sushma Panigrahy Jai Singh Parihar 《Journal of the Indian Society of Remote Sensing》2012,40(2):215-223
Quantitative remote sensing involving accurate estimation of vegetation properties relies greatly on the measurements of the
near infrared (NIR) channel because of unique interaction property between light and leaf. It is generally assumed that the
NIR measurements are made in the absence of atmospheric absorption. However, relatively weak water vapour absorption features
still persist in the NIR channel, which has bearing on the quantitative estimates of the vegetation properties and long-term
data series. This paper reports the results of a study that was carried out to infer the possible influence of the atmospheric
water vapour (WV) on the NIR measurements (0.77–0.86 μm) of Indian Remote Sensing (IRS) satellite sensors through radiative
transfer simulations using MODTRAN model. The study also suggests and evaluates the alternate band-positions for the NIR channel
to improve the IRS NIR measurements. It was observed that the water absorption features present around 0.810 μm reduces the
WV transmission of IRS NIR channel from 1 to 0.91 when atmospheric WV content increased from 0 to 6 g/cm2 and thus hampered the NIR reflectance by 14% as compared to reference signal. A significant improvement of the order of 6.5
to 12% in the NIR reflectance and 4.2 to 7% in NDVI was observed, when IRS NIR channel was split into NIR1 (0.775–0.805 μm)
and NIR2 (0.845–0.875 μm) channels by avoiding the WV absorption features. The companion paper in this issue (Pandya et al.
2011) will support results of this simulation study through the EO1-Hyperion data analysis. 相似文献
27.
S. Panigrahy V. Jain C. Patnaik J. S. Parihar 《Journal of the Indian Society of Remote Sensing》2012,40(4):599-606
In-season rice area estimation using C-band Synthetic Aperture Radar (SAR) data from RADARSAT-1 is being done in India for more than a decade. Decision rule based models in backscatter domain have been calibrated and validated using extensive field data and a long term backscatter signature bank of rice fields has been developed. Since the rice crop growing environment in India is a diverse one in the world having all the rice cultural types, the rice backscatter is quite exhaustive. This paper highlights the results of classification of rice lands in Bangladesh using the signature bank of India. The results showed that the Aman rice crop of Bangladesh has a typical temporal backscatter of shallow and intermediate rice fields of that of West Bengal state. The mean backscatter of the intermediate/deep water fields in southern Bangladesh was ?19?dB, while that of shallow cultural types mostly in northern Bangladesh was ?17?dB. The signature of the rice crop in Southern Bangladesh matched well with that of Gangetic West Bengal, particularly that of the 24 Parganas, Howrah and Hughli districts. The signature of rice crop in the Sub-Himalayan West Bengal particularly that of Dinajpur and Maldah districts matched well with that of the northern area of Bangladesh. State level rice area estimated using the selected models was found with in 5% deviation from that of the reported acreage. 相似文献
28.
Madhuparna Roy Shailendra Kumar Pradeep Pandey C. L. Bhairam P. S. Parihar 《Journal of the Geological Society of India》2014,84(4):377-384
The circular structure at Mohar (Dhala structure) in the western part of Bundelkhand Gneissic Complex, is marked by a prominent outlier of Kaimur sediments surrounded by low lying concentric sequence of sediments of Dhala Formation and basement granite breccia. This has been interpreted as a volcanic eruption related cauldron structure and meteoritic impact crater structure by various authors, on the basis of absence or presence of shock indicators in the clasts of a rhyolite-like rock that crops out scantily in the north western part of the structure. During the course of extensive sub-surface uranium exploration in this structure, the geoscientists of Atomic Minerals Directorate for Exploration and Research observed unequivocal and rampant evidences of shock metamorphic features for the first time in drill core samples of basement granitoids which constitute the bed rock for the rhyolite-like melt breccia, which overlies it. Published data of shock metamorphic features from this area are largely confined to the surface samples of the rhyolite-like melt rock, exposed in sparse outcrops. The shock metamorphic features recorded in the sub-surface granitoid bed rock samples during the present study, comprise planar deformation features (PDF) in quartz, feldspar, apatite and zircon, toasted, diaplectic, ladder-textured feldspars, selectively shock-melted feldspars and melt-veined quartz. The shock metamorphic features recorded in surface and sub-surface samples of the melt rock include ballen quartz, PDF in quartz clasts, toasted and diaplectic feldspar clasts shocked basic rock fragments with isotropised feldspars. Both the shocked bedrock granitoid and the melt rock bear uncharacteristic geochemical signatures with elevated K2O, MgO and depleted CaO. The study also observes that the melt breccia overlying the granitoid bedrock also occurs as pocket-like patches at various depths within the granitoids. Thus, the present findings have helped in understanding the attributes of the basement granitoid and associated melt breccia, thereby linking the genesis of the latter by selective melting of the former, due to the process of impact. It reinforces the already propounded theory of impact as the likely cause for the development of the structure in the basement Bundelkhand granitoid that was later filled by sediments standing out presently as a mesa. 相似文献
29.
Sushma Panigrahy S. S. Ray Anil Sood L. B. Patel P. K. Sharma J. S. Parihar 《Journal of the Indian Society of Remote Sensing》2004,32(2):209-216
A study was conducted in the Bathinda district of Punjab state for mapping the cropping pattern and crop rotation, monitoring
long term changes in cropping pattern by using the satellite based remote sensing data along other spatial and non-spatial
collateral data. Multi-date IRS LISS I and IRS WiFS sensor data have been used for this study. Cropping pattern maps and crop
rotation maps were generated for the years 1988-89 and 1998-99. The present study has shown the increase of cropping intensity
significantly, mainly due to increase in rice area. However, crop diversity has decreased mainly due to decline in the area
under the minor crops like pearl millet, gram, rapeseed/ mustard. There is increase in area coverage of cotton-wheat and rice-wheat
rotation, at the expense of the minor crops. 相似文献
30.
Bimal Kumar Bhattacharya Keshav R. Gunjal Sushma Panigrahy Jai Singh Parihar 《Journal of the Indian Society of Remote Sensing》2011,39(3):393-406
Albedo determines radiation balance of land (soil-canopy complex) surface and influence boundary layer structure of the atmosphere.
Accurate surface albedo determination is important for weather forecasting, climate projection and ecosystem modelling. Albedo-rainfall
feedback relationship has not been studied so far using observations on spatial scale over Indian monsoon region due to lack
of consistent, systematic and simultaneous long-term measurements of both. The present study used dekadal (ten-day) composite
of satellite (e.g. NOAA) based Pathfinder AVHRR Land (PAL) datasets between 1981 and 2000 over India (68–100°E, 5–40°N) at
8 km spatial resolution. Land surface albedo was computed using linear transformation of red and near infrared (NIR) surface
reflectances. The cloud effects were removed using a smoothening filter with harmonic analysis applied to time series data
in each year. The monthly, annual and long term means were computed from dekadal reconstructed albedo. The mean per year and
coefficient of variation (CV) of surface albedo over seventeen years, averaged over Indian land region, were found to show
a significantly decreasing (0.15 to 0.14 and 60 to 40%, respectively) trend between 1981 and 2000. Among all the land use
patterns, the inter-annual variation of albedo of Himalayan snow cover showed a significant and the steepest reducing trend
(0.42 – 0.35) followed by open shurbland, grassland and cropland. No significant change was noticed over different forest
types.. This could be due to increase in snow melting period and snow melt area. A strong inverse exponential relation (correlation
coefficient r = 0.95, n = 100) was found between annual rainfall and annual albedo over seven rainfall zones. The decreasing trend in snow-albedo
of accumulation period (September to March) follows the declining trend in measured south-west monsoon rainfall between 1988
(980 mm) to 1998 (880 mm) over India. This finding perhaps suggests the possible reversal of reported coupling of increased
snowfall followed by lower monsoon rainfall. 相似文献