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Stream flow forecast and its inundation simulations prior to the event are an effective and non-structural method of flood damage mitigation. In this paper, a continuous simulation hydrological and hydrodynamic model was developed for stream flow forecast and for spatial inundation simulation in Brahmani–Baitarani river basin, India. The hydrologic modelling approach includes rainfall-run-off modelling, flow routing, calibration and validation of the model with the field discharge data. CARTOSAT Digital Elevation Model of 30 m resolution, land use/land cover derived from the Indian Remote Sensing Satellite (IRS-P6) AWiFS and soil textural data of the study area were used in the modelling to compute topographic and hydraulic parameters. The hydrological model was calibrated with the help of field observed discharge data of 2006 and 2009 and validated with the data of 2008 and 2011. From the results, it is found that computed discharges are very well matching well with the observed discharges. The developed model can provide the stream flow forecast with more than 30 h lead time. Possible flood inundations were simulated using hydrodynamic modelling approach. CARTO Digital Elevation Model of 10 m resolution, landuse and the computed flood hydrographs were used in inundation simulations. 相似文献
2.
In this paper neutral point (coalescence) instability (NPI) of plasmoids (PMD) associated with tailward streaming O+, H+ and e− particles and diffusion region (spatial extent and particle life time) are studied. Also, radial and pitch angle diffusion
studies have been carried out in the near-earth region (10 and 11 RE during substorm onset. Our study revealed that coalescence instability is favoured by a heavier ion like O+ and the time required for a heavier ion to reach from one X point to an adjacent X point is minimum. Near an X type neutral
line (diffusion region) ions spend a fairly long time and gain a significant amount of energy. Radial and pitch angle diffusion
studies showed that higher energy particles are largely confined near the reconnection region (near-earth region) and lower
energy particles are rapidly depleted from the near-earth region during substorm onset. 相似文献
3.
A vertically integrated 2D numerical model was developed for the simulation of major tidal constituents (M2, S2, N2, K1 and O1) in the Bay of Bengal. The bathymetry for the model domain was derived from an improved ETOPO5 dataset prepared in our earlier work. The simulated tidal elevations showed good agreement with the hourly tide gauge observations at Paradip, Visakhapatnam, and Chennai. The amplitudes and phases of M2, S2, K1, and O1 at the coastal stations, obtained from harmonic analysis of simulated tides, were found to agree well with those obtained from Admiralty Tide Tables with the RMS misfit 9.2, 5.6, 2.9 and 3.1 cm, respectively. In the Bay of Bengal, semi-diurnal tides (M2, S2, and N2) attain highest amplitudes (180, 80, 30 cm, respectively) in the Gulf of Martaban while amplitudes of diurnal tides (K1, O1) reaches maximum (20, 12 cm, respectively) in the Malacca Strait. The continental shelf in the head bay and along the southern coast of Myanmar is about 200 km wide and the amplitudes of semi-diurnal tides are doubled in these regions while the diurnal tides amplify only marginally, which is consistent with Clarke and Battisti theory. In the north eastern end of the head bay and the Gulf of Martaban, the geometrical configuration of the coastline, in addition to the wide continental shelf, could contribute to the amplification of both semi-diurnal and diurnal constituents. In the Malacca Strait, the amplitudes of both semi-diurnal and diurnal tides are found to increase gradually from the northern end to the 2.5°N and decreases towards southern boundary. The co-tidal and co-range charts of M2 and S2 tidal constituents also show the presence of two degenerate amphidromic points in the head bay. A virtual amphidromic point for M2 is identified in the Malacca Strait. 相似文献
4.
Return period estimates of extreme sea level along the east coast of India from numerical simulations 总被引：2，自引：1，他引：1
Estimates of return periods of extreme sea level events along the coast are useful for impact assessment. In this study, a
vertically integrated 2D model was developed for the simulation of storm surges in the Bay of Bengal. The bathymetry for the
model was derived from an improved ETOPO-5 data set, which was prepared in our earlier work. The meteorological forcing for
the model was obtained from the cyclone model of Holland using the data available for 136 low-pressure systems that occurred
during 1974–2000 in the Bay of Bengal. The simulated total sea level and the surge component were obtained for each event.
The simulated peak levels showed good agreement with the observations available at few stations. The annual maxima of sea
levels, extracted from the simulations, were fitted with Gumbel distribution using r-largest annual maxima method to estimate the 5- and 50-year return periods of extreme events at 26 stations along the east
coast of India. The return periods estimated from simulated sea levels showed good agreement with those obtained from observations.
The 5- and 50-year return levels of total sea level along the east coast of India show a considerable increase from south
to north, with the 50-year return total sea levels being as high as 6.9 and 8.7 m at stations along the north eastern coast
such as Sagar Island and Chandipur, respectively. The high return levels are expected at these stations as the cyclones developed
in the Bay of Bengal generally move north or north-west, producing extreme events in the northern part, and moreover, these
stations are characterized by high tidal ranges. However, at some regions in the southern part such as Surya Lanka and Machilipatnam,
though 50-year return levels of total sea level are not very high (2.98 and 2.97 m, respectively) because of the relatively
lower tidal ranges, high return levels of surges (0.84 and 0.57 m, respectively) are found. In addition to the role of shallow
depths (5.0 and 6.1 m, respectively) at the two stations, the high return levels of surges are attributed to the effect of
geometrical configuration at Surya Lanka and width (100 km) and orientation of continental shelf at Machilipatnam. 相似文献
5.
B. Sindhu I. Suresh A. S. Unnikrishnan N. V. Bhatkar S. Neetu G. S. Michael 《Journal of Earth System Science》2007,116(3):261-274
Ocean modellers use bathymetric datasets like ETOPO5 and ETOPO2 to represent the ocean bottom topography. The former dataset
is based on digitization of depth contours greater than 200 m, and the latter is based on satellite altimetry. Hence, they
are not always reliable in shallow regions. An improved shelf bathymetry for the Indian Ocean region (20°E to 112°E and 38°S
to 32°N) is derived by digitizing the depth contours and sounding depths less than 200 m from the hydrographic charts published
by the National Hydrographic Office, India. The digitized data are then gridded and used to modify the existing ETOPO5 and
ETOPO2 datasets for depths less than 200 m. In combining the digitized data with the original ETOPO dataset, we apply an appropriate
blending technique near the 200 m contour to ensure smooth merging of the datasets. Using the modified ETOPO5, we demonstrate
that the original ETOPO5 is indeed inaccurate in depths of less than 200 m and has features that are not actually present
on the ocean bottom. Though the present version of ETOPO2 (ETOPO2v2) is a better bathymetry compared to its earlier versions,
there are still differences between the ETOPO2v2 and the modified ETOPO2. We assess the improvements of these bathymetric
grids with the performance of existing models of tidal circulation and tsunami propagation. 相似文献
6.
Sankaran Adarsh Chavan Sagar Rohidas Ali Mumtaz Sindhu Archana Devarajan Dharan Drisya Sasi Khan Muhammad Ismail 《Natural Hazards》2021,106(3):1951-1979
Natural Hazards - This study investigated the multifractal characteristics of fine resolution (0.25ox0.25°) daily gridded rainfall fields of India over the period 1901–2013 to examine... 相似文献
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