Lunar surface mineralogy using hyperspectral data: Implications for primordial crust in the Earth–Moon system     

V. Sivakumar  R. Neelakantan  M. Santosh 《地学前缘(英文版)》2017,8(3):457-465

Mineralogy of the Lunar surface provides important clues for understanding the composition and evolution of the primordial crust in the Earth–Moon system. The primary rock forming minerals on the Moon such as pyroxene, olivine and plagioclase are potential tools to evaluate the Lunar Magma Ocean (LMO) hypothesis. Here we use the data from Moon Mineralogy Mapper (M³) onboard the Chandrayaan-1 project of India, which provides Visible/Near Infra Red (NIR) spectral data (hyperspectral data) of the Lunar surface to gain insights on the surface mineralogy. Band shaping and spectral profiling methods are used for identifying minerals in five sites: the Moscoviense basin, Orientale basin, Apollo basin, Wegener crater-highland, and Hertzsprung basin. The common presence of plagioclase in these sites is in conformity with the anorthositic composition of the Lunar crust. Pyroxenes, olivine and Fe-Mg-spinel from the sample sites indicate the presence of gabbroic and basaltic components. The compositional difference in pyroxenes suggests magmatic differentiation on the Lunar surface. Olivine contains OH/H₂O band, indicating hydrous phase in the primordial magmas.  相似文献   

Intra-Seasonal Oscillations Associated with Indian Ocean Warm Pool and Summer Monsoon Rainfall and Their Inter-Annual Variability     

P. M. Muraleedharan  P. G. Nisha  P. V. Sathe  K. U. Sivakumar 《Journal of the Indian Society of Remote Sensing》2012,40(1):75-83

Sea surface temperature (SST) and wind speed (WS) derived from Multichannel Scanning Microwave Radiometer (MSMR), onboard IRS-P4 (Oceansat-1) satellite were used to generate spatially averaged (80° to 100° E & 0° to 10° S) daily data during June to September from 1999 to 2001 along with collocated outgoing long wave radiation (OLR) data from NCEP/NCAR reanalysis product. Daily rainfall data over the peninsular India during the above period was taken from the weekly weather report published by the Indian Meteorological Department. The data were then subjected to power spectral analysis. Dominant 30 to 60 days oscillations were observed over both ocean and land during all the 3 years investigated. It is quite interesting to note that the intra-seasonal oscillation with 60 days periodicity dominates in both ocean and land during 1999 and then transforms to 30 and 40 days periodicities in 2000 and 2001 respectively with a phase lag of about 25 to 30 days. It was also observed that the time-latitude section of zonally averaged OLR and TMI derived cloud liquid water data clearly depict the propagation of convection and cloud from the equator to the north at the rate of 0.75° to 1° latitude per day which corroborates well with the rate of propagation derived from the phase lag obtained between the processes occurring at the equatorial Indian Ocean and rainfall recorded at the designated land segments. The results are in good agreement with the observations made by earlier investigators.  相似文献   

DEM Generation for Lunar Surface using Chandrayaan-1 TMC Triplet Data   总被引：1，自引：0，他引：1  

V. Sivakumar  Binay Kumar  Sandeep Kumar Srivastava  B. Gopala Krishna  Pradeep Kumar Srivastava  A. S. Kiran Kumar 《Journal of the Indian Society of Remote Sensing》2012,40(4):551-564

Digital Elevation Model (DEM) is an important prerequisite for understanding the lunar surface. However, making accurate DEM is a very challenging task due to (a) lack of support of projection parameters in COTS packages (eg. PCI Geomatica), which are to be used in generation of Lunar DEM and (b) unavailability of Ground Control Points (GCPs). In the present study, DEM generation of lunar surface was attempted without GCPs using Rational Function (RF) model from Chandrayaan-1 TMC triplet images. In the study, a good correlation (of almost same order) is observed between Nadir-Fore (NF), Nadir - Aft (NA), Fore - Aft (FA) and Fore - Nadir - Aft (FNA) image pairs. The results suggest that DEM for lunar surface can be created without GCPs using RF model.  相似文献   

Nonlinear analysis of rainfall dynamics in California's Sacramento Valley   总被引：1，自引：0，他引：1  

Bellie Sivakumar  Wesley W. Wallender  William R. Horwath  Jeffrey P. Mitchell  Samuel E. Prentice  Brian A. Joyce 《水文研究》2006,20(8):1723-1736

This study investigates the dynamic nature of rainfall observed at the Sustainable Agriculture Farming Systems (SAFS) site in California's Sacramento Valley, which was established to study the benefits of winter cover cropping in Mediterranean irrigated‐arid systems. Rainfall data of four different temporal scales (i.e. daily, weekly, biweekly, and monthly) are analysed to determine the dynamic nature of precipitation in time. In an arid climate with seasonal precipitation this has large implications for land and water management, both in the short term and in the long term. A nonlinear dynamic technique (correlation dimension method) that uses the phase‐space reconstruction and dimension concepts is employed. Bearing in mind the possible effects of the presence of zeros (i.e. no rain) on the outcomes of this analysis, an attempt is also made to compare the dynamic nature of all‐year rainfall and winter rainfall. Analysis of 15 years of data suggests that rainfall dynamics at this site are dominated by a large number of variables, regardless of the scales and seasons studied. The dimension results also suggest that: (1) rainfall dynamics at coarser resolutions are more irregular than that at finer resolutions; (2) winter rainfall has a higher variability than all‐year rainfall. These results are indeed useful to gain information about the complexity of the rainfall process at this site with respect to (temporal) scales and seasons and, hence, the appropriate model (high‐dimensional) type. However, in view of the potential effects of certain rainfall data characteristics (e.g. zeros, measurement errors, scale effects) on the correlation dimension analysis, the discussion also emphasizes the need for further verification, and possibly confirmation, of these results. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Assessment of the influence of physical and seismotectonic parameters on landslide occurrence: an integrated geoinformatic approach     

Sivakumar  R.  Ghosh  Snehasish 《Natural Hazards》2021,108(3):2765-2811

Natural Hazards - Landslide is a devastating natural hazard, which causes significant losses of human lives and properties. The landslide occurrences are the perennial problem in Himalayan region...  相似文献   

Investigating chaos in river stage and discharge time series     

Rahman Khatibi  Bellie Sivakumar  Mohammad Ali Ghorbani  Ozgur Kisi  Kasim Koçak  Davod Farsadi Zadeh 《Journal of Hydrology》2012

  相似文献   

Water resources and environment in Australia     

Bellie Sivakumar 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(1):1-2

  相似文献   

Regional variation of recession flow power‐law exponent          下载免费PDF全文

Swagat Patnaik  Basudev Biswal  Dasika Nagesh Kumar  Bellie Sivakumar 《水文研究》2018,32(7):866-872

Recession flows of a basin provide valuable information about its storage–discharge relationship as during recession periods discharge occurs due to depletion of storage. Storage–discharge analysis is generally performed by plotting ?dQ/dt against Q , where Q is discharge at time t . For most real world catchments, ?dQ/dt versus Q show a power‐law relationship of the type: ?dQ/dt = kQ^α . Because the coefficient k varies across recession events significantly, the exponent α needs to be computed separately for individual recession events. The median α can then be considered as the representative α for the basin. The question that arises here is what are the basin characteristics that influence the value of α ? Studies based on a small number of basins (up to 50 basins) reveal that α has good relationship with several basin characteristics. However, whether such a relationship is universal remains an important question, because a universal relationship would allow prediction of the value of α for any ungauged basin. To test this hypothesis, here, we study data collected from a relatively large number of basins (358 basins) in USA and examine the influence of 35 different physio‐climatic characteristics on α . We divide the basins into 2 groups based on their longitudes and test the relationship between α and basin characteristics separately for the two groups. The results indicate that α is not identically influenced by different basin characteristics for the two datasets. This may suggest that the power‐law exponent α of a region is determined by the way local physio‐climatic forces have shaped the landscape.  相似文献   

Field and Laboratory Observations on Predation and Prey Selectivity of the Scyphomedusa Chrysaora cf. caliparea in Southeast Indian Waters     

Govindan Kanagaraj  Pazhaniyappan Ezhilarasan  Pitchai Sampathkumar  Andre C. Morandini  Velayudhan pillai Sivakumar 《青岛海洋大学学报(英文版)》2011,(1):47-54

  相似文献   

Climate: patterns, changes, and impacts     

Bellie Sivakumar  George Christakos 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(4):443-444

  相似文献