Formate and acetate levels compared in monsoon and winter rainwater at Dayalbagh, Agra (India)     

Nandini Kumar  U. C. Kulshrestha  A. Saxena  P. Khare  K. M. Kumari  S. S. Srivastava 《Journal of Atmospheric Chemistry》1996,23(1):81-87

A total of 59 rainwater samples were collected during the winter and monsoon (1991–92) at Dayalbagh, Agra. This site is relatively free from the influence of anthropogenic emissions and the volume-weighted average concentrations (VWA) of formate in the winter and monsoon were 22.5±6, 16.1±3 while acetate VWAs were 17.1±5 and 13.8±3 mol l^-1, respectively. Although the VWAs varied between seasons, it was not statistically different. Total deposition (in mmol m^-2) varied between season (winter formate, 1.4; acetate, 1.1; monsoon formate, 7.4; acetate, 6.4). A difference in VWA values may have occurred as a result of the dilution factor; the total rain depth from collected samples in the monsoon was 46 cm while that in winter was 6.3 cm. Sources at this site may be anthropogenic and natural; scavenging from the vapour phase, washout of soil particles and emissions from vegetative sources are probably important sources for formate and acetate.  相似文献   

Optical properties of some terrestrial rocks and glasses     

James B. Pollack  Owen B. Toon  Bishun N. Khare 《Icarus》1973,19(3):372-389

The optical constants of five naturally occurring rocks have been determined in the spectral range between 0.2 and .50 μm. Between 0.2 and 5 μm, the real and imaginary parts of the index of refraction were found from a combination of reflectivity and transmission measurements by using Beer's law and the Fresnel reflectivity equation. At wavelenths beyond 5 μm only reflectivity measurements could be made and both constants were found from an application of classical dispersion theory. These optical constants will be valuable for studies of the interaction of light with rock surfaces, atmospheric dust and interplanetary and interstellar dust grains.  相似文献   

Can benthic foraminiferal morpho-groups be used as indicators of paleomonsoonal precipitation?     

Rajiv Nigam  Neloy Khare  D.V. Borole 《Estuarine, Coastal and Shelf Science》1992,34(6)

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On the temperature dependence of possible S₈ infrared bands in planetary atmospheres     

B.N. Khare  Carl Sagan 《Icarus》1977,30(1):231-233

Measurements of the temperature dependence between 77 and 333°K of the infrared spectrum of cyclic octatomic sulfur suggest that the 23 μm Jovian feature very tentatively identified by Houck et al. [Science 189, 720–722 (1975)] is not due to S₈; and that the temperature dependence of the frequency of the 835 cm^? band of S₈ may be a useful temperature marker in planetary studies.  相似文献   

Morphometric and rheological study of lunar domes of Marius Hills volcanic complex region using Chandrayaan-1 and recent datasets     

A S Arya  R P Rajasekhar  Koyel Sur  B Gopala Krishna  K Suresh  T P Srinivasan  K V Iyer  P Chauhan  Ajai  A S Kiran Kumar  A D Pandey  A Khare  P K Verma 《Journal of Earth System Science》2018,127(5):70

Marius Hills volcanic complex is one of the most important regions on the lunar surface having an abundant number of volcanic features like domes and cones. Systematic mapping of 106 domes/cones in the Marius Hills region was carried out in this study using high-resolution orthoimage and digital elevation models of Chandrayaan-1 and Kaguya missions. Various morphometric parameters like diameter, height, volume, flank slope, circularity index and form factor are derived for all the mapped domes. The rheological parameters, such as viscosity and eruption rate are estimated for isolated domes and cones superimposed over low domes. The morphometric and rheological properties of these domes are comparable to those located in the area near to Hortensius crater and other mare regions. Surface ages derived for a selected region in NW portion of the Marius Hills volcanic complex using crater size-frequency distribution technique yields ages of 2.98 and 1.91 Ga. It suggests that the domes in this region formed at about 2.98 Ga ago, and then, the younger mare basalts likely embayed this region about 1.98 Ga ago. Stratigraphic sequence of rilles, wrinkle ridge and domes shows that wrinkle ridges are the oldest, while the rilles are younger than the domes.  相似文献   

Elevational distribution of butterflies in the Himalayas: a case study from Langtang National Park,Nepal     

Ranjit Pandey  Kapil K. Khadka  Anuj Ghimire  Puja Jha  Umesh Pathak 《山地科学学报》2017,14(7):1384-1390

Mountain ecosystems are relatively more vulnerable to climate change since human induced climate change is projected to be higher at high altitudes and latitudes. Climate change induced effects related to glacial response and water hazards have been documented in the Himalayas in recent years, yet studies regarding species’ response to climate change are largely lacking from the mountains and Himalayas of Nepal. Changes in distribution and latitudinal/altitudinal range shift, which are primary adaptive responses to climate change in many species, are largely unknown due to unavailability of adequate data from the past. In this study, we explored the elevational distribution of butterflies in Langtang Village Development Committee (VDC) of Langtang National park; a park located in the high altitudes of Nepal. We found a decreasing species richness pattern along the elevational gradient considered here. Interestingly, elevation did not appear to have a significant effect on the altitudinal distribution of butterflies at family level. Also, distribution of butterflies in the area was independent of habitat type, at family level. Besides, we employed indicator group analysis (at family level) and noticed that butterfly families Papilionidae, Riodinidae, and Nymphalidae are significantly associated to high, medium and low elevational zone making them indicator butterfly family for those elevational zones, respectively. We expect that this study could serve as a baseline information for future studies regarding climate change effects and range shifts and provide avenues for further exploration of butterflies in the high altitudes of Nepal.  相似文献   

Trend analysis using discrete wavelet transform (DWT) for long-term precipitation (1851–2006) over India     

Brij Kishor Pandey  Harinarayan Tiwari  Deepak Khare 《水文科学杂志》2017,62(13):2187-2208

This study is an attempt to determine the trends in monthly, annual and monsoon total precipitation series over India by applying linear regression, the Mann-Kendall (MK) test and discrete wavelet transform (DWT). The linear regression test was applied on five consecutive classical 30-year climate periods and a long-term precipitation series (1851–2006) to detect changes. The sequential Mann-Kendall (SQMK) test was applied to identify the temporal variation in trend. Wavelet transform is a relatively new tool for trend analysis in hydrology. Comparison studies were carried out between decomposed series by DWT and original series. Furthermore, visualization of extreme and contributing events was carried out using the wavelet spectrum at different threshold values. The results showed that there are significant positive trends for annual and monsoon precipitation series in North Mountainous India (zone NMI) and North East India (NEI), whereas negative trends were detected when considering India as whole.