Modeling potential forest fire danger using modis data     

K. V. S. Badarinath  K. Madhavilatha  T. R. Kiran Chand  M. S. R. Murthy 《Journal of the Indian Society of Remote Sensing》2004,32(4):343-350

Generation of fire danger maps play a vital role in forest fire management like forest fire research, locating lookout towers, risk assessment and for various other simulation studies. The present study addresses remote sensing and GIS applications in generating fire danger maps for tropical deciduous forests. Fire danger variables such as fuel type, topography, temperature, and relative humidity have been used in modeling fire danger. Information on local climate patterns and past fire records has been used to derive fire frequency map of the study area. Intermediate indices were derived using multiple regressions, where fire frequency data is taken as dependent variable. Results indicate that forests near human settlements are more vulnerable to forest fires.  相似文献   

Efficient encoding and decoding algorithms for distributed resampling     

D. Vamsi Kiran  C. Srinivasa Rao  R. Ramakrishnan  P. Gupta 《Journal of the Indian Society of Remote Sensing》2004,32(3):269-286

This paper discusses algorithms for compressing floating point data which is encountered while performing resampling algorithm for rectifying geometric distortions on the images transmitted by the remote sensing satellite on a distributed computing environment. Two efficient algorithms for encoding and decoding floating point data compression, (i) 3-byte packing and (ii) 3-byte + 2-bit packing have been proposed. Both algorithms are tested to execute resampling algorithm on radiometrically corrected for IRS- LISS-III 4 bands data on a distributed system. First algorithm compresses 4-byte floating point data to 3-byte obtaining 25% compression while later one compresses 4-byte floating point data to 3-byte + 2-bit achieving about 18.75% compression. The computational time is reduced by 22% as compared to the distributed resampling algorithms without compression. Further it is found that in lossy compression algorithm only 220 pixels out of 37.4 MB pixels have utmost one Gray count difference, which will not pose any issues for digital classification or any other methods that will be employed in the corrected image by Image Analysts.  相似文献   

UNCERTAINTY IN THE SPECIFICATION OF SURFACE CHARACTERISTICS: A STUDY OF PREDICTION ERRORS IN THE BOUNDARY LAYER   总被引：1，自引：0，他引：1  

Kiran Alapaty  Sethu Raman  Devdutta S. Niyogi 《Boundary-Layer Meteorology》1997,82(3):475-502

The effects of uncertainty in the specification of surface characteristics on simulated atmospheric boundary layer (ABL) processes and structure were investigated using a one-dimensional soil-vegetation-boundary layer model. Observational data from the First International Satellite Land Surface Climatology Project Field Experiment were selected to quantify prediction errors in simulated boundary-layer parameters. Several numerical 12-hour simulations were performed to simulate the convective boundary-layer structure, starting at 0700 LT 6 June 1987.In the control simulation, measured surface parameters and atmospheric data were used to simulate observed boundary-layer processes. In the remaining simulations, five surface parameters – soil texture, initial soil moisture, minimum stomatal resistance, leaf area index, and vegetation cover – were varied systematically to study how uncertainty in the specification of these surface parameters affects simulated boundary-layer processes.The simulated uncertainty in the specification of these five surface parameters resulted in a wide range of errors in the prediction of turbulent fluxes, mean thermodynamic structure, and the depth of the ABL. Under certain conditions uncertainty in the specifications of soil texture and minimum stomatal resistance had the greatest influence on the boundary-layer structure. A lesser but still moderately strong effect on the simulated ABL resulted from (1) a small decrease (4%) in the observed initial soil moisture (although a large increase [40%] had only a marginal effect), and (2) a large reduction (66%) in the observed vegetation cover. High uncertainty in the specification of leaf area index had only a marginal impact on the simulated ABL. It was also found that the variations in these five surface parameters had a negligible effect on the simulated horizontal wind fields. On the other hand, these variations had a significant effect on the vertical distribution of turbulent heat fluxes, and on the predicted maximum boundary-layer depth, which varied from about 1400–2300 m across the 11 simulations. Thus, uncertainties in the specification of surface parameters can significantly affect the simulated boundary-layer structure in terms of meteorological and air quality model predictions.  相似文献   

Spectral analysis of wind and temperature components during lightning in pre-monsoon season over Ranchi     

Arun K. Dwivedi  Sagarika Chandra  Manoj Kumar  Sanjay Kumar  N. V. P. Kiran Kumar 《Meteorology and Atmospheric Physics》2015,127(1):95-105

  相似文献   

Peak ground motion predictions in India: an appraisal for rock sites   总被引：1，自引：0，他引：1  

Sankar Kumar Nath  Kiran Kumar Singh Thingbaijam 《Journal of Seismology》2011,15(2):295-315

Proper selection and ranking of Ground Motion Prediction Equations (GMPEs) is critical for successful logic-tree implementation in probabilistic seismic hazard analysis. The present study explores this issue in predicting peak ground accelerations at the rock sites in India. Macroseismic intensity data complemented with limited strong ground-motion recordings are used for the purpose. The findings corroborate the possible conformity between the GMPEs developed for tectonically active shallow crust across the globe. On the other hand, the relevant GMPEs in the intraplate regions cluster into two different groups with the equations of lower ranks catering to higher ground motions. The earthquakes in the subduction zones have significant regional implications. However, affinity in the ground-motion attenuations between the major interface events (M _W > 7.4) in Andaman-Nicobar, Japan and Cascadia, respectively, is noted. This can be also observed for the intraslab events in the Hindukush and Taiwan respectively. Overall, we do not observe any significant advantage with the equations developed using the regional data. These findings are expected to be useful in probabilistic seismic hazard analysis across the study region.  相似文献   

Variations in Oscillation Frequencies From Minimum to Maximum of Solar Activity     

Jain  Kiran  Bhatnagar  A. 《Solar physics》2003,213(2):257-268

The temporal variation in intermediate-degree-mode frequencies is analysed using helioseismic data which cover the minimum to the maximum phase of the current solar cycle. To study the variation in detail, the measured frequency shifts of f and p modes are decomposed into two components, viz., oscillatory and non-oscillatory. The f-mode frequencies exhibit prominent oscillatory behavior in contrast to p modes where the oscillatory nature of the frequencies is not clearly seen. Also, the oscillatory part contributes significantly to the f-mode frequencies while p-mode frequencies have maximum contribution from the non-oscillatory part. The amplitude of both oscillatory and non-oscillatory parts is found to be a function of frequency. The non-oscillatory part is observed to have a strong correlation with solar activity.  相似文献   

Polarimetric Study of Comets C/1995 O1 (Hale–Bopp) and C/2000 Wm1 (Linear)     

Joshi  Umesh C.  Baliyan  Kiran S.  Ganesh  Shashikiran 《Earth, Moon, and Planets》2002,90(1-4):413-421

We made polarimetric observations of comet Hale–Bopp covering awide phase angle range, from 18.8 to 47°. At certain phase angles the heliocentricdistance of the comet was less than 1 AU during its pre and post perihelion passages. Oneof the important findings, based on the data in the visual bands, is the higher polarizationwith stronger wavelength dependence compared to comet Halley, indicating the presenceof much finer grains in comet Hale–Bopp. It may also be noted that comet Hale–Bopphas shown highest degree of polarization known so far for any comet and hence fallsin the class of high polarization comets. Polarimetric observations were made of cometC/2000 WM1 (LINEAR)using narrow band (IHW) filters 4845 Å and 7000 Åand broad bands filters BVR during November 23–26, 2001 when the phase angle rangedfrom 15 to 22°. Some of the results based on these observations are presented anddiscussed.  相似文献   

The future projection of cyclones in Bay of Bengal: a study using coupled ocean atmosphere model     

Kiran  P V  Balaji  C 《Ocean Dynamics》2022,72(8):641-660

Ocean Dynamics - In this study, the behaviour of cyclones in the Bay of Bengal in future climatic conditions is analysed with the help of an ocean-atmosphere coupled model. The weather research and...  相似文献   

Interaction of the WAT Source in A3395 with the Intracluster Medium     

Kiran Lakhchaura  K. P. Singh  D. J. Saikia  R. W. Hunstead 《Journal of Astrophysics and Astronomy》2011,32(4):493-494

Using X-ray observations from Chandra and XMM-Newton and radio observations from the Australia Telescope Compact Array (ATCA), we have examined the merging environment of the bimodal cluster Abell 3395. From X-ray data we have produced thermodynamic maps of the cluster. The Wide Angle Tail (WAT) galaxy seen in the radio is slightly offset from the X-ray emission peak of the southern part of the cluster. The unsharp masked Chandra image of the cluster does not show any deficit in the X-ray flux near the location of the source possibly because the thermal plasma has leaked into the cavities.  相似文献   

Ground-motion predictions in Shillong region, northeast India   总被引：1，自引：0，他引：1  

Sankar Kumar Nath  Kiran Kumar Singh Thingbaijam  Soumya Kanti Maiti  Avinash Nayak 《Journal of Seismology》2012,16(3):475-488

We deliver ground-motion prediction equations for Shillong region, northeast India, based on a database generated by finite-fault stochastic simulations. An examination of the regional seismic source characteristics is carried out beforehand. Micro/minor earthquakes (M _W?<?5.0) nucleating at hypocentral depth <21?km in the region recorded at broadband seismic stations are observed to have Brune stress-drop ranging between 2.8 and 99.9?bars. Likewise, macroseismic intensity data for the 1897 Shillong Earthquake that nucleated at a hypocentral depth of ~35?km places the associated stress-drop at 100?200?bars. The apparent variation of the stress-drop parameter with depth is considered with two source zones namely lower-crust and upper-crust. Equations for the lower-crust predict higher ground-motion levels and exhibit affinity to those developed for stable continental region of Eastern North America. The ground-motion levels predicted by the equations for the upper-crust are relatively lower but are still higher compared with those predicted for tectonically active regions, viz., the Himalayas and Western North America.  相似文献