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Research was conducted to develop a method for obtaining floating pan evaporation rates in a small (less than 10,000 m~2) wetland, lagoon, or pond. Floating pan and land pan evaporation data were collected from March 1 to August 3...
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Research was conducted to develop a method for obtaining floating pan evaporation rates in a small (less than 10,000 m~2) wetland, lagoon, or pond. Floating pan and land pan evaporation data were collected from March 1 to August 31, 2005, at a small natural wetland located in the alluvium of the Canadian River near Norman, Oklahoma, at the U.S. Geological Survey Norman Landfill Toxic Substances Hydrology Research Site. Floating pan evaporation rates were compared with evaporation rates from a nearby standard Class A evaporation pan on land. Floating pan evaporation rates were significantly less than land pan evaporation rates for the entire period and on a monthly basis. Results indicated that the use of a floating evaporation pan in a small free-water surface better simulates actual physical conditions on the water surface that control evaporation. Floating pan to land pan ratios were 0.82 for March, 0.87 for April, 0.85 for May, 0.85 for June, 0.79 for July, and 0.69 for August.
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Acceleration of the global water cycle over recent decades remains uncertain because of the high inter-annual variability of its components. Observations of pan evaporation (E_(pan)), a proxy of potential evapotranspiration (ET_p)...
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Acceleration of the global water cycle over recent decades remains uncertain because of the high inter-annual variability of its components. Observations of pan evaporation (E_(pan)), a proxy of potential evapotranspiration (ET_p), may help to identify trends in the water cycle over long periods. The complementary relationship (CR) states that ET_p and actual evapotranspiration (ET_a) depend on each other in a complementary manner, through land-atmosphere feedbacks in water-limited environments. Using a long-term series of E_(pan) observations in Australia, we estimated monthly ET_a by the CR and compared our estimates with ET_a measured at eddy covariance Fluxnet stations. The results confirm that our approach, entirely data-driven, can reliably estimate ET_a only in water-limited conditions. Furthermore, our analysis indicated that ET_a did not show any significant trend in the last 30 years, while short-term analysis may indicate a rapid climate change that is not perceived in a long-term perspective.
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This study evaluates the potential of 8-band high resolution WorldView-2 (WV-2) panchromatic (PAN) and multispectral image (MSI) data for the extraction of polar geospatial information. We introduce a novel method based on a custo...
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This study evaluates the potential of 8-band high resolution WorldView-2 (WV-2) panchromatic (PAN) and multispectral image (MSI) data for the extraction of polar geospatial information. We introduce a novel method based on a customized set of normalized difference Spectral Index Ratios (SIRs), incorporating multiple bands, to improve the accuracy of land-cover mapping in the Antarctic. Most recently available WV-2 data are classified into land-cover surfaces such as snow/ice, water bodies, and landmass using the customized normalized difference SIRs. A novel multi-fold methodology is used to evaluate the effect of pan-sharpening algorithms on spectral characteristics of satellite data, and on subsequent land-cover mapping using an array of SIRs. A set of existing pan-sharpening algorithms was implemented in order to fuse PAN with MSI data, followed by estimation of multiple SIRs to extract target land-cover classes. These algorithms were compared on the basis of their effectiveness in extracting target classes using a defined set of SIRs. Our results indicate that the use of 8-band WV-2, customized SIRs, and appropriate pan-sharpening can greatly improve the extraction of land-cover information.
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There is mounting evidence that permafrost degradation has occurred over the past century. However, the amount of permafrost lost is uncertain because permafrost is not readily observable over long time periods and large scales. T...
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There is mounting evidence that permafrost degradation has occurred over the past century. However, the amount of permafrost lost is uncertain because permafrost is not readily observable over long time periods and large scales. This paper uses JULES, the land surface component of the Hadley Centre global climate model, driven by different realisations of twentieth century meteorology to estimate the pan-arctic changes in near-surface permafrost. Model simulations of permafrost are strongly dependent on the amount of snow both in the driving meteorology and the way it is treated once it reaches the ground. The multi-layer snow scheme recently adopted by JULES significantly improves its estimates of soil temperatures and permafrost extent. Therefore JULES, despite still having a small cold bias in soil temperatures, can now simulate a near-surface permafrost extent which is comparable to that observed. Changes in snow cover have been shown to contribute to changes in permafrost and JULES simulates a significant decrease in late twentieth century pan-Arctic spring snow cover extent. In addition, large-scale modelled changes in the active layer are comparable with those observed over northern Russia. Simulations over the period 1967-2000 show a significant loss of near-surface permafrost—between 0.55 and 0.81 million km per decade with this spread caused by differences in the driving meteorology. These runs also show that, for the grid cells where the active layer has increased significantly, the mean increase is ～10 cm per decade. The permafrost degradation discussed here is mainly caused by an increase in the active layer thickness driven by changes in the large scale atmospheric forcing. However, other processes such as thermokarst development and river and coastal erosion may also occur enhancing permafrost loss.
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A field study was conducted on chickpea (Cicer arietinum) crop by using different irrigation techniques, normal furrow and raised bed systems at during four rabi season. The experiment consisted of three planting techniques viz., ...
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A field study was conducted on chickpea (Cicer arietinum) crop by using different irrigation techniques, normal furrow and raised bed systems at during four rabi season. The experiment consisted of three planting techniques viz., normal (farmers practice) planting, 60 cm raisec bed and 120 cm raised bed and three-irrigation schedules i.e. 0.8 IW/CPE, 0.6 IW/ CPE, and 0.4 IW/CPE ratio. The four years rabi seasons (2009-10 to 2012-13) pooled results revealed that, a higher chickpea grain yield of 13.35q/ha, gross income of Rs 10,565/ha, net income of Rs 5,628/ha and B: C ratio of 2.82 was obtained by irrigation level of 0.8 IW/CPE irrigation treatment. A significantly superior water use efficiency of 4.95 kg/ha-mm was observed with irrigation level at 0.4 IW/CPE. Planting on 120 cm raised bed treatments, a higher chickpea grain yield of 13.83 q /ha, water use efficiency of 20.15 kg/ha mm, gross income of Rs 10,376/ ha and net income of Rs 5426/ha and B : C ratio of 3.21 recorded. A significantly superior water use efficiency of 5.34 kg/ha mm was observed with 120 cmraised bed. The interaction between irrigation 0.8 IW/CPE ratio and 120 cm raised bed configuration treatment recorded a higher grain yield (15.38 q/ha) and this result also on par with the 120 cm raised bed with the 0.6 IW/CPE and 0.4IW/CPE ratio irrigation treatments. The water saving with irrigation level of 0.4 IW/CPE ratio was 47 and 26% over 0.6 IW/CPE and 0.8 IW/CPE ratio treatment respectively. Whereas the water saving in irrigation level with 0.6 IW/CPE ratio was 28% over 0.8 IW/CPE ratio with120 cm raised bed.
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In recent years, the demand for very high geometric resolution satellite images has increased significantly. The pan-sharpening techniques, which are part of the data fusion techniques, enable the increase in the geometric resolut...
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In recent years, the demand for very high geometric resolution satellite images has increased significantly. The pan-sharpening techniques, which are part of the data fusion techniques, enable the increase in the geometric resolution of multispectral images using panchromatic imagery of the same scene. However, it is not trivial to choose a suitable pan-sharpening algorithm: there are several, but none of these is universally recognized as the best for any type of sensor, in addition to the fact that they can provide different results with regard to the investigated scene. This article focuses on the latter aspect: analyzing pan-sharpening algorithms in relation to different land covers. A dataset of GeoEye-1 images is selected from which four study areas (frames) are extracted: one natural, one rural, one urban and one semi-urban. The type of study area is determined considering the quantity of vegetation included in it based on the normalized difference vegetation index (NDVI). Nine pan-sharpening methods are applied to each frame and the resulting pan-sharpened images are compared by means of spectral and spatial quality indicators. Multicriteria analysis permits to define the best performing method related to each specific area as well as the most suitable one, considering the co-presence of different land covers in the analyzed scene. Brovey transformation fast supplies the best results among the methods analyzed in this study.
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Grove Mountains consists mainly of a series of high-grade (upper amphibolite to granu-lite fades) metamorphic rocks, including felsic granulite, granitic gneiss, mafic granulite lenses and charnockite, intruded by late tectonic gn...
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Grove Mountains consists mainly of a series of high-grade (upper amphibolite to granu-lite fades) metamorphic rocks, including felsic granulite, granitic gneiss, mafic granulite lenses and charnockite, intruded by late tectonic gneissic granite and post-tectonic granodioritic veins. Geo-chemical analysis demonstrates that the charnockite, granitic gneiss and granite belonged to aluminous A type plutonic rocks, whereas the felsic and mafic granulite were from supracrustal materials as island-arc, oceanic island and middle oceanic ridge basalt. A few high-strained shear zones disperse in regional stable sub-horizontal foliated metamorphic rocks. Three generations of ductile deformation were identified, in which D_1 is related to the event before Pan-African age, D_2 corresponds to the regional granulite peak metamorphism, whereas D_3 reflects ductile extension in late Pan-African orogenic period. The metamorphic reactions from granitic gneiss indicate a single granulite facies event, but 3 steps from mafic granulite, with P-T condition of M_1 800℃, 9.3 x 10~5 Pa; M_2 800— 810℃, 6.4 x 10~5 Pa ; and M_3 650℃ have been recognized. The U-Pb age data from representative granitic gneiss indicate (529+-14) Ma of peak metamorphism, (534+-5) Ma of granite emplacement, and (501+-7) Ma of post-tectonic granodioritic veins. All these evidences suggest that a huge Pan-African aged mobile belt exists in the East Antarctic Shield extending from Prydz Bay via Grove Mountains to the southern Prince Charles Mountains. This orogenic belt could be the final suture during the Gondwana Land assemblage.
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After Rodinia supercontinent was disintegrated in Late Proterozoic, an ocean, namely, Tethys Ocean, occurred between Gondwana continental group and Pan-Cathaysian continental group from Late Proterozoic to Mesozoic. From Early Pal...
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After Rodinia supercontinent was disintegrated in Late Proterozoic, an ocean, namely, Tethys Ocean, occurred between Gondwana continental group and Pan-Cathaysian continental group from Late Proterozoic to Mesozoic. From Early Paleozoic to Mesozoic, Tethys Ocean was subducted toward Pan-Cathaysian block group, which results in backarc expansion, arc-land collision and forearc accretion. When the backarc basin expands and reaches the small oceanic basin, ophiolite melange will be generated. As accretion had already occurred in the south of the continental margin in the earlier stage, the succeeding backarc expansion and the frontal arc position were migrated toward south correspondingly. Therefore, multiple ophiolite belts and magmatic rock belts occurred, and show a trend of decreasing age from north toward south. As the continental margin was split and migrated toward south and reached a high latitude position, i.e., with the shortening and subduction of oceanic crust, the sedimentary bodies at high latitude was accreted continuously toward low latitude area together with the formation of oceanic island, mixing of cold-type and warm-type organism was generated. Moreover, blocks split and separated from Pan-Cathaysian or Gondwana continental group cannot traverse the oceanic median ridge and joins with another continental block. As a result, the Kunlun belt on the SW margin of the Pan-Cathaysian land was resulted from the multi-arc orogenesis such as the backarc seabed expansion, arc-arc collision, arc-land collision oceanic bed, and the continuous southward accretion process.
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A field study was conducted on maize (Zea ways L.) crop by using raised bed land configuration and different irrigation techniques for three kharif season (2011 to 2013). The three years kharif seasons pooled results revealed that...
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A field study was conducted on maize (Zea ways L.) crop by using raised bed land configuration and different irrigation techniques for three kharif season (2011 to 2013). The three years kharif seasons pooled results revealed that a significantly superior maize grain yield of 60.0 q ha~(-1), gross income of Rs 51,136 ha~(-1). net income of Rs 31,459 ha~(-1) and B:C ratio of 2.60 was obtained by irrigation level of 0.6 IW/CPE irrigation treatment. A significantly higher water use efficiency of 16.65 kg (ha-mm)-' was observed with irrigation level at 0.4 IW / CPE and this result also at par with the 0.6 IW / CPE ratio. Planting on 120 cm raised bed treatments. Significantly superior maize grain yield of 60.7 q ha~(-1), gross income of Rs 52,973 ha~(-1) and net income of Rs 35,973 ha-' and B:C ratio of 2.87 recorded. A higher water use efficiency of 15.85 kg (ha-mm)"' was observed with 120 cm raised bed. The interaction between irrigation 0.6 IW / CPE ratio and 120 cm raised bed configuration treatment recorded a significantly superior grain yield of 66.26 q ha~(-1), gross income of Rs 52,686 ha~(-1), net income of Rs 36,314 ha~(-1) and J3:C ratio of 2.65. A higher WUE of 15.47 kg (ha-mm)"' was recorded with120 cm raised bed and 0.6 IW / CPE ratio.
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