共查询到20条相似文献,搜索用时 31 毫秒
1.
Some characteristics of very heavy rainfall over Orissa during summer monsoon season 总被引:1,自引:0,他引:1
Orissa is one of the most flood prone states of India. The floods in Orissa mostly occur during monsoon season due to very
heavy rainfall caused by synoptic scale monsoon disturbances. Hence a study is undertaken to find out the characteristic features
of very heavy rainfall (24 hours rainfall ≥125 mm) over Orissa during summer monsoon season (June–September) by analysing
20 years (1980–1999) daily rainfall data of different stations in Orissa. The principal objective of this study is to find
out the role of synoptic scale monsoon disturbances in spatial and temporal variability of very heavy rainfall over Orissa.
Most of the very heavy rainfall events occur in July and August. The region, extending from central part of coastal Orissa
in the southeast towards Sambalpur district in the northwest, experiences higher frequency and higher intensity of very heavy
rainfall with less interannual variability. It is due to the fact that most of the causative synoptic disturbances like low
pressure systems (LPS) develop over northwest (NW) Bay of Bengal with minimum interannual variation and the monsoon trough
extends in west-northwesterly direction from the centre of the system. The very heavy rainfall occurs more frequently with
less interannual variability on the western side of Eastern Ghat during all the months and the season except September. It
occurs more frequently with less interannual variability on the eastern side of Eastern Ghat during September. The NW Bay
followed by Gangetic West Bengal/Orissa is the most favourable region of LPS to cause very heavy rainfall over different parts
of Orissa except eastern side of Eastern Ghat. The NW Bay and west central (WC) Bay are equally favourable regions of LPS
to cause very heavy rainfall over eastern side of Eastern Ghat. The frequency of very heavy rainfall does not show any significant
trend in recent years over Orissa except some places in north-east Orissa which exhibit significant rising trend in all the
monsoon months and the season as a whole. 相似文献
2.
S. R. Kalsi 《Journal of Earth System Science》2000,109(2):211-220
BOBMEX-Pilot was organised from 23rd October–11th November, 1998 when the seasonal trough had already shifted to south Bay
of Bengal. The activity during this period was marked by the development of a monsoon depression from 26th–29th October that
weakened over the sea; onset of northeast monsoon along the east coast of India on 29th October; a low pressure area that
formed on 2nd November over southwest Bay off Sri Lanka — southTamilnadu coast; and another cyclonic circulation that formed
towards the end of the BOBMEX-Pilot period. This paper describes the development of these synoptic systems through synoptic
charts and satellite data. 相似文献
3.
Meteorological fields variability over the Indian seas in pre and summer monsoon months during extreme monsoon seasons 总被引:1,自引:0,他引:1
U. C. Mohanty R. Bhatla P. V. S. Raju O. P. Madan A. Sarkar 《Journal of Earth System Science》2002,111(3):365-378
In this study, the possible linkage between summer monsoon rainfall over India and surface meteorological fields (basic fields
and heat budget components) over monsoon region (30‡E-120‡E, 30‡S30‡N) during the pre-monsoon month of May and summer monsoon
season (June to September) are examined. For this purpose, monthly surface meteorological fields anomaly are analyzed for
42 years (1958-1999) using reanalysis data of NCEP/NCAR (National Center for Environmental Prediction/National Center for
Atmospheric Research). The statistical significance of the anomaly (difference) between the surplus and deficient monsoon
years in the surface meteorological fields are also examined by Student’s t-test at 95% confidence level.
Significant negative anomalies of mean sea level pressure are observed over India, Arabian Sea and Arabian Peninsular in the
pre-monsoon month of May and monsoon season. Significant positive anomalies in the zonal and meridional wind (at 2 m) in the
month of May are observed in the west Arabian Sea off Somali coast and for monsoon season it is in the central Arabian Sea
that extends up to Somalia. Significant positive anomalies of the surface temperature and air temperature (at 2 m) in the
month of May are observed over north India and adjoining Pakistan and Afghanistan region. During monsoon season this region
is replaced by significant negative anomalies. In the month of May, significant positive anomalies of cloud amount are observed
over Somali coast, north Bay of Bengal and adjoining West Bengal and Bangladesh. During monsoon season, cloud amount shows
positive anomalies over NW India and north Arabian Sea.
There is overall reduction in the incoming shortwave radiation flux during surplus monsoon years. A higher magnitude of latent
heat flux is also found in surplus monsoon years for the month of May as well as the monsoon season. The significant positive
anomaly of latent heat flux in May, observed over southwest Arabian Sea, may be considered as an advance indicator of the
possible behavior of the subsequent monsoon season. The distribution of net heat flux is predominantly negative over eastern
Arabian Sea, Bay of Bengal and Indian Ocean. Anomaly between the two extreme monsoon years in post 1980 (i.e., 1988 and 1987)
shows that shortwave flux, latent heat flux and net heat flux indicate reversal in sign, particularly in south Indian Ocean.
Variations of the heat budget components over four smaller sectors of Indian seas, namely Arabian Sea, Bay of Bengal and west
Indian Ocean and east Indian Ocean show that a small sector of Arabian Sea is most dominant during May and other sectors showing
reversal in sign of latent heat flux during monsoon season. 相似文献
4.
V. Ramesh Babu V. S. N. Murty L. V. G. Rao C. V. Prabhu V. Tilvi 《Journal of Earth System Science》2000,109(2):255-265
Hydrographic data collected on board ORV Sagar Kanya in the southern Bay of Bengal during the BOBMEX-Pilot programme (October–November
1998) have been used to describe the thermohaline structure and circulation in the upper 200 m water column of the study region.
The presence of seasonal Inter-Tropical Convergence Zone (ITCZ) over the study area, typically characterized with enhanced
cloudiness and flanked by the respective east/northeast winds on its northern part and west/southwest winds on its southern
part, has led to net surface heat loss of about 55 W/m2. The sea surface dynamic topography relative to 500 db shows that the upper layer circulation is characterised by a cyclonic
gyre encompassing the study area. The eastward flowing Indian Monsoon Current (IMC) between 5‡N and 7‡N in the south and its
northward branching along 87‡E up to 13‡N appear to feed the cyclonic gyre. The Vessel-Mounted Acoustic Doppler Current Profiler
(VM-ADCP) measured currents confirm the presence of the cyclonic gyre in the southern Bay of Bengal during the withdrawing
phase of the southwest monsoon from the northern/central parts of the Bay of Bengal. 相似文献
5.
In this article, the interannual variability of certain dynamic and thermodynamic characteristics of various sectors in the
Asian summer monsoon domain was examined during the onset phase over the south Indian peninsula (Kerala Coast). Daily average
(0000 and 1200 UTC) reanalysis data sets of the National Centre for Environmental Prediction/National Centre for Atmospheric
Research (NCEP/NCAR) for the period 1948–1999 were used. Based on 52 years onset date of the Indian summer monsoon, we categorized
the pre-onset, onset, and post-onset periods (each an average of 5 days) to investigate the interannual variability of significant
budget terms over the Arabian Sea, Bay of Bengal, and the Indian peninsula. A higher difference was noticed in low-level kinetic
energy (850 hPa) and the vertically integrated generation of kinetic energy over the Arabian Sea from the pre-onset, onset,
and post-onset periods. Also, significant changes were noticed in the net tropospheric moisture and diabatic heating over
the Arabian Sea and Indian peninsula from the pre-onset to the post-onset period. It appears that attaining the magnitude
of 40 m2 s−2 and then a sharp rise in kinetic energy at 850 hPa is an appropriate time to declare the onset of the summer monsoon over
India. In addition to a sufficient level of net tropospheric moisture (40 mm), a minimum strength of low-level flow is needed
to trigger convective activity over the Arabian Sea and the Bay of Bengal. An attempt was also made to develop a location-specific
prediction of onset dates of the summer monsoon over India based on energetics and basic meteorological parameters using multivariate
statistical techniques. The regression technique was developed with the data of May and June for 42 years (1948–1989) and
validated with 10 years NCEP reanalysis from 1990 to 1999. It was found that the predicted onset dates from the regression
model are fairly in agreement with the observed onset dates obtained from the Indian Meteorology Department. 相似文献
6.
The satellite-derived moisture fields during different phases of two normal and poor monsoon years have been studied. Spectral
analysis was performed in different zones of the monsoon region to study the nature and modes of intraseasonal fluctuations
of lower layer moisture fields.
Seasonal mean fields of water vapour at low and middle layers show a dry anomaly over the Arabian subcontinent and a wet anomaly
over the Bay of Bengal during good monsoon years, while the anomalies show an opposite trend during the poor monsoon years.
The zonal and meridional propagation of low-frequency oscillations of moisture fields has also been examined. The southward
movement of low-frequency oscillations seems to be suppressed in good monsoon years as compared to the poor monsoon years,
whereas the northward movement of the same shows no particular difference. Fluctuations in the 30–50 day range are found shifted
to longer time-period side in the poor monsoon years. 相似文献
7.
A special feature of the Bay of Bengal circulation is its seasonal variation in response to the monsoonal winds. In the case
of the Bay of Bengal, observationally very little is known about the large scale circulation. Theoretically, the problem of
driving the circulation in the Bay of Bengal is more complex than that in other basins because of the presence of large quantities
of fresh water discharge from Ganga-Brahmaputra-Meghna river systems, and also because the atmospheric driving forces even
within a season are highly variable with frequent occurrences of tropical disturbances. Exploring the nature of the circulation
in the Bay of Bengal is a problem of great importance in itself as well as for the critical role this region plays in the
genesis of tropical disturbances which are the main source of large scale rainfall over the northern part of the Indian subcontinent.
The surface circulation of the Bay of Bengal may, therefore, help in understanding the variation of rainfall over time scales
ranging from the subseasonal to the interannual.
Keeping this in view, an attempt was made towards the development of an oceanic climatological circulation model for the Bay
of Bengal, which explains the seasonal variability of the currents. The model is fully non-linear and vertically integrated,
with realistic basin geometry. The treatment of coastal boundaries involves a procedure leading to a realistic curvilinear
representation of the western and eastern sides of the Bay of Bengal. This coastal representation has the advantage of taking
into account the finer resolution in the shallow regions of the northern Bay.
The model is forced by the monthly mean wind stress derived from 30 years (1950–79) of Comprehensive Oceanographic Atmospheric
Data Sets (COADS). Special emphasis is given to the southern open boundary condition for the model. For this purpose, sensitivity
experiments have been performed with six open boundary conditions and a comparative study of the results has been made. These
sensitivity tests for the open boundary condition will help the development of a suitable coupled ocean-atmosphere model for
this region. The model-generated main features are in general agreement with the known climatological circulation of the Bay
of Bengal. 相似文献
8.
Nityanand Singh 《Journal of Earth System Science》1995,104(1):1-36
Large-scale interannual variability of the northern summer southwest monsoon over India is studied by examining its variation
in the dry area during the period 1871–1984. On the mean summer monsoon rainfall (June to September total) chart the 800 mm
isohyet divides the country into two nearly equal halves, named as dry area (monsoon rainfall less than 800 mm) and wet area
(monsoon rainfall greater than 800 mm). The dry area/wet area shows large variations from one year to another, and is considered
as an index for assessing the large-scale performance of the Indian summer monsoon. Statistical and fluctuation characteristics
of the summer monsoon dry area (SMDA) are reported.
To identify possible causes of variation in the Indian summer monsoon, the correlation between the summer monsoon dry area
and eleven regional/global circulation parameters is examined. The northern hemisphere surface air temperature, zonal/hemispheric/global
surface air and upper air temperatures, Southern Oscillation, Quasi-biennial oscillation of the equatorial lower stratosphere,
April 500-mb ridge along 75°E over India, the Indian surface air temperature and the Bombay sea level pressure showed significant
correlation.
A new predictor parameter that is preceding year mean monsoon rainfall of a few selected stations over India has been suggested
in the present study. The stations have been selected by applying the objective technique ‘selecting a subset of few gauges
whose mean monsoon rainfall of the preceding year has shown the highest correlation coefficient (CC) with the SMDA’. Bankura
(Gangetic West Bengal), Cuddalore (Tamil Nadu) and Anupgarh (West Rajasthan) entered the selection showing a CC of 0.724.
Using a dependent sample of 1951–1980 a predictive model (multiple CC = 0.745) has also been developed for the SMDA with preceding
year mean monsoon rainfall of the three selected stations and the sea level pressure tendency at Darwin from Jan–Feb to Mar–May
as independent parameters. 相似文献
9.
The characteristic features of the marine boundary layer (MBL) over the Bay of Bengal during the southwest monsoon and the
factors influencing it are investigated. The Bay of Bengal and Monsoon Experiment (BOBMEX) carried out during July–August
1999 is the first observational experiment under the Indian Climate Research Programme (ICRP). A very high-resolution data
in the vertical was obtained during this experiment, which was used to study the MBL characteristics off the east coast of
India in the north and south Bay of Bengal. Spells of active and suppressed convection over the Bay were observed, of which,
three representative convective episodes were considered for the study. For this purpose a one-dimensional multi-level PBL
model with a TKE-ε closure scheme was used. The soundings, viz., the vertical profiles of temperature, humidity, zonal and
meridional component of wind, obtained onboard ORV Sagar Kanya and from coastal stations along the east coast are used for
the study. The temporal evolution of turbulent kinetic energy, marine boundary layer height (MBLH), sensible and latent heat
fluxes and drag coefficient of momentum are simulated for different epochs of monsoon and monsoon depressions during BOBMEX-99.The
model also generates the vertical profiles of potential temperature, specific humidity, zonal and meridional wind. These simulated
values compared reasonably well with the observations available from BOBMEX. 相似文献
10.
Temporal variation in abundance and mean proloculus diameter of the benthic foraminiferal speciesEpistominella exigua has been reconstructed over the last ∼ 50,000 yr BP, from a core collected from the distal Bay of Bengal fan, to assess its
potential application in palaeoceanographic reconstruction studies. The down-core variation shows significant change in abundance
ofE. exigua during the last ∼ 50,000 yr BP. In view of the present day abundance of this species from areas with strong seasonal organic
matter supply, we conclude that at ∼ 7, ∼ 22, ∼ 33 and ∼ 46kyr BP, strong seasonality prevailed in the distal Bay of Bengal
fan, probably indicating either strong or prolonged north-east monsoon or weakened south-west monsoon. For the first time,
a strong correlation is observed in abundance and mean proloculus diameter ofE. exigua. Based on coherent variation in mean proloculus diameter and abundance, it is postulated that mean proloculus diameter can
also be used to infer increased seasonality in organic matter production, thus variation in strength or duration of monsoon.
Thus, this study establishes that the down-core variation in the abundance and mean proloculus diameter ofEpistominella exigua can be used to infer past climatic variations from the distal Bay of Bengal fan. 相似文献
11.
The summer monsoon rainfall over Orissa, a state on the eastern coast of India, is more significantly related than Indian
summer monsoon rainfall (ISMR) to the cyclonic disturbances developing over the Bay of Bengal. Orissa experiences floods and
droughts very often due to variation in the characteristics of these disturbances. Hence, an attempt was made to find out
the inter-annual variability in the rainfall over Orissa and the frequencies of different categories of cyclonic disturbances
affecting Orissa during monsoon season (June–September). For this purpose, different statistical characteristics, such as
mean, coefficient of variation, trends and periodicities in the rainfall and the frequencies of different categories of cyclonic
disturbances affecting Orissa, were analysed from 100 years (1901–2000) of data. The basic objective of the study was to find
out the contribution of inter-annual variability in the frequency of cyclonic disturbances to the inter-annual variability
of monsoon rainfall over Orissa.
The relationship between summer monsoon rainfall over Orissa and the frequency of cyclonic disturbances affecting Orissa shows
temporal variation. The correlation between them has significantly decreased since the 1950s. The variation in their relationship
is mainly due to the variation in the frequency of cyclonic disturbances affecting Orissa. The variability of both rainfall
and total cyclonic disturbances has been above normal since the 1960s, leading to more floods and droughts over Orissa during
recent years. The inter-annual variability of seasonal rainfall over Orissa and the frequency of cyclonic disturbances affecting
Orissa during monsoon season show a quasi-biennial oscillation period of 2–2.8 years. There is least impact of El Nino southern
oscillation (ENSO) on inter-annual variability of both the seasonal rainfall over Orissa and the frequencies of monsoon depressions/total
cyclonic disturbances affecting Orissa. 相似文献
12.
Doppler sodar wind data for the boundary layer over Kharagpur obtained during MONTBLEX-1990 at a height interval of 30 m from
surface up to 1500 m have been analysed for the periods when intense synoptic scale disturbances from north Bay of Bengal
moved along the eastern end of the monsoon trough. The variation in the vertical wind profile in the lower boundary layer
over Kharagpur during the passage of synoptic scale disturbances has been discussed in the paper. The analysis indicates that
the mean winds over Kharagpur veered with height in the lower boundary layer near the surface suggesting divergence over Kharagpur
when the system lay south/southwest of the station. No such veering has been noticed when the centre of the system lay very
close to the station. 相似文献
13.
The Indian Climate Research Programme (ICRP) focuses on the study of climate variability and its impact on agriculture. To
address the role of the Bay of Bengal in monsoon variability, a process study was organised during July–August 1999, deploying
research ships, buoys, INSAT, coastal radar and conventional observational systems to collect information about the coupled
ocean-atmosphere system over the warm waters of the Bay of Bengal. The paper gives the background of the ICRP and the organisation
and implementation of the Bay of Bengal Monsoon Experiment (BOBMEX) in its field phase. 相似文献
14.
FABIEN DURAND FABRICE PAPA ATIQUR RAHMAN SUJIT KUMAR BALA 《Journal of Earth System Science》2011,120(5):859-872
This study investigates the impact of monthly Ganges–Brahmaputra river discharge variations on Bay of Bengal salinity and
temperature during the period 1992–1999. The Ganges–Brahmaputra river discharge is characterized by a well-defined seasonal
cycle with strong interannual variations. The highest/lowest yearly peak discharge occurs in summer 1998/summer 1992, with
1998 value amounting to twice that of 1992. This river discharge is then used to force an ocean general circulation model.
Our main result is that the impact of these rivers on the variability of Bay of Bengal sea surface salinity is strong in the
northern part, with excess run-off forcing fresh anomalies, and vice versa. Most of the years, the influence of the interannual variability of river discharge on the Bay salinity does not extend south
of ~10°N. This stands in contrast with the available observations and is probably linked to the relatively coarse resolution
of our model. However, the extreme discharge anomaly of 1998 is exported through the southern boundary of the Bay and penetrates
the south-eastern Arabian Sea a few months after the discharge peak. In response to the discharge anomalies, the model simulates
significant mixed-layer temperature anomalies in the northern Bay of Bengal. This has the potential to influence the climate
of the area. From our conclusions, it appears necessary to use a numerical model with higher resolution (both on the horizontal
and vertical) to quantitatively investigate the upper Bay of Bengal salinity structure. 相似文献
15.
T. K. Manual Ateef Khan Y. Nazeer Ahammed R. S. Tanwar R. S. Parmar K. S. Zalpuri Prabhat K. Gupta S. L. Jain Risal Singh A. P. Mitra S. C. Garg A. Suryanarayana V. S. N. Murty M. Dileep Kumar Andrew J. Shepherd 《Journal of Earth System Science》2006,115(4):473-484
Characteristics of trace gases (O3, CO, CO2, CH4 and N2O) and aerosols (particle size of 2.5 micron) were studied over the Arabian Sea, equatorial Indian Ocean and southwest part
of the Bay of Bengal during the monsoon transition period (October–November, 2004). Flow of pollutants is expected from south
and southeast Asia during the monsoonal transition period due to the patterns of wind flow which are different from the monsoon
period. This is the first detailed report on aerosols and trace gases during the sampled period as the earlier Bay of Bengal
Experiment (BOBMEX), Arabian Sea Monsoon Experiment (ARMEX) and Indian Ocean Experiments (INDOEX) were during monsoon seasons.
The significant observations during the transition period include: (i) low ozone concentration of the order of 5 ppbv around
the equator, (ii) high concentrations of CO2, CH4 and N2O and (iii) variations in PM2.5 of 5–20μg/m3. 相似文献
16.
The structure and interannual variability of the 30–50 day oscillation over the Indian region have been studied during the monsoon season. The power spectra of the zonal component of wind show large power in the 30–50 day time scale. The oscillation has a meridional wavelength of about 25° latitude and a slow northward phase speed of about 0.7° latitude per day. The oscillation also has some interannual variability. The periods are somewhat longer during the drought years. 相似文献
17.
Weakening of lower tropospheric temperature gradient between Indian landmass and neighbouring oceans and its impact on Indian monsoon 总被引:2,自引:0,他引:2
S. M. Bawiskar 《Journal of Earth System Science》2009,118(4):273-280
The study shows that in the scenario of global warming temperature gradient (TG) between Indian landmass and Arabian Sea/Bay
of Bengal is significantly decreasing in the lower troposphere with maxima around 850 hPa. TG during pre-monsoon (March to
May) is reducing at a significant rate of 0.036°/year (Arabian Sea) and 0.030°/year (Bay of Bengal). The above alarming results
are based on sixty years (1948–2007) of daily temperature and wind data extracted from CDAS-NCEP/NCAR reanalysis datasets.
TG based on ERA-40 data also indicates a decreasing trend of 0.0229°/year and 0.0397°/year for Arabian Sea and Bay of Bengal
respectively. As TG is not governed by any type of significant oscillation, there is a possibility of TG tending to zero.
It is further observed that the rate of warming over the oceans is more than that over the land which has resulted into the
weakening of TG. Pre-monsoon TG has significant correlations with
Except AISMR, the decreasing trends observed in all the above parameters are significant. All India rainfall for July and
August together shows a significant decreasing trend of 0.995mm/year. Reducing number of depressions and cyclonic storms and
increasing number of break days during monsoon over India are the reflections of the weakening of TG. 相似文献
• | All India Seasonal Monsoon Rainfall (AISMR) |
• | kinetic energy of waves 1 and 2 at 850 hPa |
• | kinetic energy, and |
• | stream function at 850 hPa over Indian landmass during monsoon season. |
18.
SAVITA PATWARDHAN ASHWINI KULKARNI K KRISHNA KUMAR 《Journal of Earth System Science》2012,121(1):203-210
A state-of-the-art regional climate modelling system, known as PRECIS (Providing REgional Climates for Impacts Studies) developed
by the Hadley Centre for Climate Prediction and Research, UK is applied over the Indian domain to investigate the impact of
global warming on the cyclonic disturbances such as depressions and storms. The PRECIS simulations at 50 × 50 km horizontal
resolution are made for two time slices, present (1961–1990) and the future (2071–2100), for two socioeconomic scenarios A2
and B2. The model simulations under the scenarios of increasing greenhouse gas concentrations and sulphate aerosols are analysed
to study the likely changes in the frequency, intensity and the tracks of cyclonic disturbances forming over north Indian
Ocean (Bay of Bengal and Arabian Sea) and the Indian landmass during monsoon season. The model overestimates the frequency
of cyclonic disturbances over the Indian subcontinent in baseline simulations (1961–1990). The change is evaluated towards
the end of present century (2071–2100) with respect to the baseline climate. The present study indicates that the storm tracks
simulated by the model are southwards as compared to the observed tracks during the monsoon season, especially for the two
main monsoon months, viz., July and August. The analysis suggests that the frequency of cyclonic disturbances forming over
north Indian Ocean is likely to reduce by 9% towards the end of the present century in response to the global warming. However,
the intensity of cyclonic disturbances is likely to increase by about 11% compared to the present. 相似文献
19.
Aftab Alam Khan 《Natural Hazards》2012,61(3):1127-1141
Geodynamic status, seismo-tectonic environment, and geophysical signatures of the Bay of Bengal do not support the occurrence
of seismogenic tsunami. Since thrust fault and its intensity and magnitude of rupture are the key tectonic elements of tsunamigenic
seismic sources, the study reveals that such characteristics of fault-rupture and seismic sources do not occur in most of
the Bay of Bengal except a small segment in the Andaman–Nicobar subduction zone. The inferred segment of the Andaman–Nicobar
subduction zone is considered for generating a model of the deformation field arising from fluid-driven source. The model
suggests local tsunami with insignificant inundation potential along the coast of northern Bay of Bengal. The bathymetric
profile and the sea floor configuration of the northern Bay of Bengal play an important role in flattening the waveform through
defocusing process. The direction of motion of the Indian plate makes an angle of about 30° with the direction of the opening
of Andaman Sea. The opening of Andaman Sea and the direction of plate motion of the Indian plate results in the formation
of Andaman trench where the subducting plate dives more obliquely than that in the Sunda trench in the south. The oblique
subduction reduces significantly the possibilities of dominant thrust faulting in the Andaman subduction zone. Further, north
of Andaman subduction in the Bengal–Arakan coast, there is no active subduction. On the otherhand, much greater volume of
sediments (in excess of 20 km) in the Bengal–Arakan segment reduces the possibilities of mega rupture of the ocean floor.
The water depth (≈1,000 m) along most of the northern Bay of Bengal plate margin is not optimum for any significant tsunami
generation. Hence, very weak possibility of any significant tsunami is suggested that based on the interpretation of geodynamic
status, seismo-tectonic environment, and geophysical signatures of the Andaman subduction zone and the Bengal–Arakan coast. 相似文献
20.
The intra-seasonal variability observed in the salinity field of the upper layers at a few locations in the east central Arabian
Sea and the northern Bay of Bengal during the summer monsoon seasons of 1977 and 1979 is documented with the aid of short
time series (1–2 weeks) of salinity measurements made from USSR and Indian ships deployed during MONSOON-77 (1977) and MONEX-79
(1979) field experiments. In the Arabian Sea a typical subsurface maxima observed beneath the mixed layer base either disappeared
or considerably weakened due to strong vertical mixing caused by the monsoonal forcing. In the northern Bay of Bengal the
salinity variability in the top 30 m water column was rapid and appeared to be influenced by large amounts of fresh water
from rain and probably from the major adjoining rivers. Some simple diagnostic calculations are presented to assess the relative
importance of various processes which control the observed salinity variability. 相似文献