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A Hidden Markov Model (HMM) has been developed for prediction of quantitative snowfall in Pir-Panjal and Great Himalayan mountain ranges of Indian Himalaya. The model predicts snowfall for two days in advance using daily recorded nine meteorological variables of past 20 winters from 1992–2012. There are six observations and six states of the model. The most probable observation and state sequence has been computed using Forward and Viterbi algorithms, respectively. Baum–Welch algorithm has been used for optimizing the model parameters. The model has been validated for two winters (2012–2013 and 2013–2014) by computing root mean square error (RMSE), accuracy measures such as percent correct (PC), critical success index (CSI) and Heidke skill score (HSS). The RMSE of the model has also been calculated using leave-one-out cross-validation method. Snowfall predicted by the model during hazardous snowfall events in different parts of the Himalaya matches well with the observed one. The HSS of the model for all the stations implies that the optimized model has better forecasting skill than random forecast for both the days. The RMSE of the optimized model has also been found smaller than the persistence forecast and standard deviation for both the days.  相似文献   
23.
Yadava  Pramod Kumar  Soni  Manish  Verma  Sunita  Kumar  Harshbardhan  Sharma  Ajay  Payra  Swagata 《Natural Hazards》2020,101(1):217-229
Natural Hazards - Lightning, a climate-related highly localized natural phenomenon, claims lives and damage properties. These losses could only be reduced by the identification of active seasons...  相似文献   
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Verma  Sunita  Sharma  Ajay  Yadava  Pramod Kumar  Gupta  Priyanshu  Singh  Janhavi  Payra  Swagata 《Natural Hazards》2022,112(2):1379-1393
Natural Hazards - The present study investigates the accelerating factors for extreme flash flood at Chamoli district of Uttarakhand on 7 February 2021. The Sentinel-2A and 2B satellite data have...  相似文献   
25.
Ghani  Sufyan  Kumari  Sunita 《Natural Hazards》2022,111(3):2995-3029
Natural Hazards - The present research aims to co-relate the plasticity and liquefaction response of soil as well as its significance in defining liquefaction probability. To accomplish this,...  相似文献   
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Geotechnical and Geological Engineering - The present work aims to understand the stress–strain response of an igneous rock, metadolerite, typically found in dyke form, under high loading...  相似文献   
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Prakash  Divya  Payra  Swagata  Verma  Sunita  Soni  Manish 《Natural Hazards》2013,69(3):1767-1779

In this study, the aerosol behavior during two contradictory events, i.e., dust storm (DS) and Diwali (DW) has been studied over Jaipur. The aerosol particle number concentration shows distinct features between DS and DW events. The total ANC was found minimum during DS while maximum during DW. The 24 h mean of total ANC was 9.15 × 104 (±7.71 × 104) and 5.38 × 105 (±3.73 × 105 particles/l) during DS and DW, respectively. The total ANC increases from 7.78 × 104 to 5.32 × 105 and 3.52 × 105 to 1.70 × 106 particles/l in 24 h during DS and DW, respectively. In DS, the ANC in coarse mode (2 < particle diameter < 20 μm) is significantly high while in DW, the ANC in fine mode (0.3 < particle diameter < 2 μm) exhibits higher concentration. During dust episode, a significant change in ANC (3.0 × 103 to 1.12 × 105 particles/l) was observed for the particle of size range in 2.0–20 μm with a slight increase in particles number concentration (7.48 × 104 to 4.20 × 105 particles/l) in 0.3–2.0 μm range is also observed. During DS, the fine and coarse mode particles increased 4.61 and 36.44 times while during DW, it increased 3.83 and 0.95 times, respectively. The relatively high particle levels during DW are attributed for two reasons: local emissions due to burning of fire crackers and meteorological conditions, i.e., low wind speeds and low mixing-layer heights lead to relatively high particle concentrations.

  相似文献   
28.
The fully coupled Biot quasi-static theory of linear poroelasticity is used to study the consolidation of a poroelastic half-space caused by axisymmetric surface loads. The fluid and solid constituents of the poroelastic medium are compressible and its permeability in the vertical direction is different from its permeability in the horizontal direction. An analytical solution of the governing equations is obtained by taking the displacements and the pore pressure as the basic state variables and using a combination of the Laplace and Hankel transforms. The problem of an axisymmetric normal load is discussed in detail. An explicit analytical solution is obtained for normal disc loading. Detailed numerical computations reveal that the anisotropy in permeability as well as the compressibilities of the fluid and solid constituents of the poroelastic medium have significant effects on the consolidation of the half-space. The anisotropy in permeability may accelerate the consolidation process and may lead to a dilution in the theoretical prediction of the Mandel-Cryer effect. The compressibility of the solid constituents may also accelerate the consolidation process.  相似文献   
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