scholarly journals Analysis of rainfall pattern and extreme events during southwest monsoon season over Varanasi during 1971-2010

MAUSAM ◽  
2021 ◽  
Vol 67 (4) ◽  
pp. 903-912
Author(s):  
R. BHATLA ◽  
A. TRIPATHI ◽  
R. S. SINGH
Keyword(s):  
Extreme Events ◽  
Monsoon Season ◽  
Uttar Pradesh ◽  
Daily Rainfall ◽  
Recent Decade ◽  
Southwest Monsoon ◽  
Total Period ◽  
Rainfall Events ◽  
Cumulative Rainfall ◽  
Southwest Monsoon Season

An attempt has been made to detect the pattern of rainfall and examine the trends and variations of extreme events of rainfall over Varanasi (Uttar Pradesh, India) through seasonal, monthly and decadal analysis during southwest monsoon season (June-September) using the daily rainfall data of 40 years period from 1971-2010. The results show that cumulative rainfall during 1971-2010 is overall decreasing in monsoon season as well as in all the months June, July, August and September. In general, the observed rainfall events in all categories (Non rainy day, 0-2.4 mm; Category I, 2.5-64.4; Category II, 64.5 to 124.4; Category III, 124.5 mm or more) have a decreasing trend in all the months and monsoon season over the entire period of study. However, decadal analysis reveals that in general frequency of rainfall events in almost every category is decreasing in recent decade. Different results are seen in August, as cumulative rainfall is decreasing in this month, whereas very heavy and exceptionally heavy rainfall events and their contribution have increased in recent decade as well as over total period.  

scholarly journals Study of rainfall features over Goa state during southwest monsoon season

MAUSAM ◽  
2021 ◽  
Vol 61 (2) ◽  
pp. 155-162
Author(s):  
S. M. METRI ◽  
KHUSHVIR SINGH
Keyword(s):  
Heavy Rainfall ◽  
Monsoon Season ◽  
Southwest Monsoon ◽  
Annual Rainfall ◽  
Statistical Parameters ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Average Rainfall ◽  
Southwest Monsoon Season ◽  
Heavy Rainfall Events

In this paper the rainfall features at different raingauge stations of Goa state have been studied for the period of 30 years. The statistical parameters such as mean monthly rainfall, Standard Deviation and Coefficient of Variation have been computed for each raingauge station of Goa. Some heavy rainfall events during the period have also been studied. The study shows the significant rising trend of rainfall towards the eastern parts of Goa. Goa experiences an average rainfall of about 330 cm annually and around 90% of annual rainfall occurs during southwest monsoon season i.e. (June to September). Studies revealed that most of heavy rainfall events caused due to active off-shore trough and low pressure systems formed over southeast Arabian Sea. It has also come out from the study that the orography of Goa plays an important role in rainfall distribution. Valpoi receives maximum rainfall due to its orographic effect.

scholarly journals Occurrence of dry and wet weeks over Maharashtra

MAUSAM ◽  
2021 ◽  
Vol 51 (1) ◽  
pp. 25-38
Author(s):  
P. G. GORE ◽  
V. THAPLIYAL
Keyword(s):  
High Probability ◽  
Markov Chain Model ◽  
Monsoon Season ◽  
Daily Rainfall ◽  
Southwest Monsoon ◽  
The State ◽  
Chain Model ◽  
Temporal And Spatial Distribution ◽  
The North ◽  
Southwest Monsoon Season

Based on the daily rainfall data of the past 90 years (1901-90), the initial and conditional probabilities of a wet week and the probabilities of 2 and 3 consecutive wet weeks have been computed for all the districts of Maharashtra during the southwest monsoon season by using Markov Chain model. A temporal and spatial distribution of probabilities of wet weeks have been studied in detail. Most of the districts show the highest probability of wet weeks during July. A few number of the districts show the second highest probability during August. The western and northeastern parts of the state show 10-16 wet weeks with high probability. The high rainfall districts along the west coast show high wet week probabilities during most of the period of the season. A few number of the districts from moderate rainfall zone, show high probability of a wet week during, July and August. A persistency in rainfall is noticed in only extreme western parts of the state. The east-west variation along 19° N shows 'L' shaped pattern for the high probability wet weeks. While, the north -south variation of the wet weeks with high probability shows a sinusoidal curve from north to south.

scholarly journals Variability and probabilistic estimates of rainfall extremes In Bangladesh during the southwest monsoon season

MAUSAM ◽  
2022 ◽  
Vol 46 (1) ◽  
pp. 47-56
Author(s):  
SAMARENDRA KARMAKAR ◽  
AYESHA KHATUN
Keyword(s):  
Extreme Events ◽  
Monsoon Season ◽  
Southwest Monsoon ◽  
Monthly Rainfall ◽  
Spatial Distributions ◽  
North Eastern ◽  
Rainfall Extremes ◽  
The Mean ◽  
Temporal And Spatial ◽  
Southwest Monsoon Season

The present study describes the temporal and spatial distributions of mean monthly rainfall and its variability together with the spatial distributions of the probabilistic estimates of rainfall extremes over Bangladesh during the- southwest monsoon season. The- probabilistic rainfall extremes have been computed for IWO lime scales: (a) in I year out of 4 years, and (b) in 1 year out of 10 years -representing relatively less extreme events and extreme events respectively. The mean monthly rainfall increases from June to July at most places over Bangladesh and then decreases up to September. The variability of rainfall decreases with increasing rainfall up to July at many places and then increases up to September. The study also reveals that the mean rainfall and the- probabilistic rainfall extremes are maximum over the southern and north-eastern parts of the country where the variability of rainfall is low and the rainfall is reliable. There exists a belt of low rainfall over the- central part of Bangladesh roughly between 23oN and 24°N. The rainfall gradients are maximum over north-eastern Bangladesh and the gradients of the probabilistic high rainfall are more than those of the probabilistic low rainfall in this area.  

scholarly journals Spatial structures and directionalities in Monsoonal precipitation over South Asia

2010 ◽  
Vol 17 (5) ◽  
pp. 371-381 ◽  
Author(s):  
N. Malik ◽  
N. Marwan ◽  
J. Kurths
Keyword(s):  
Indian Subcontinent ◽  
Monsoon Season ◽  
Daily Rainfall ◽  
Heavy Rain ◽  
Data Sets ◽  
Spatial Structures ◽  
Break Phase ◽  
Rainfall Events ◽  
Monsoonal Precipitation ◽  
Rain Events

Abstract. Precipitation during the monsoon season over the Indian subcontinent occurs in form of enormously complex spatiotemporal patterns due to the underlying dynamics of atmospheric circulation and varying topography. Employing methods from nonlinear time series analysis, we study spatial structures of the rainfall field during the summer monsoon and identify principle regions where the dynamics of monsoonal rainfall is more coherent or homogenous. Moreover, we estimate the time delay patterns of rain events. Here we present an analysis of two separate high resolution gridded data sets of daily rainfall covering the Indian subcontinent. Using the method of event synchronization (ES), we estimate regions where heavy rain events during monsoon happen in some lag synchronised form. Further using the delay behaviour of rainfall events, we estimate the directionalities related to the progress of such type of rainfall events. The Active (break) phase of a monsoon is characterised by an increase(decrease) of rainfall over certain regions of the Indian subcontinent. We show that our method is able to identify regions of such coherent rainfall activity.

scholarly journals Beaching patterns of plastic debris along the Indian Ocean rim

2020 ◽  
Author(s):  
Mirjam van der Mheen ◽  
Erik van Sebille ◽  
Charitha Pattiaratchi
Keyword(s):  
Indian Ocean ◽  
Bay Of Bengal ◽  
Plastic Material ◽  
Monsoon Season ◽  
Southwest Monsoon ◽  
Plastic Waste ◽  
Ocean Dynamics ◽  
Global Ocean ◽  
The Indian Ocean ◽  
Southwest Monsoon Season

Abstract. A large percentage of global ocean plastic waste enters the northern hemisphere Indian Ocean (NIO). Despite this, it is unclear what happens to buoyant plastics in the NIO. Because the subtropics in the NIO is blocked by landmass, there is no subtropical gyre and no associated subtropical garbage patch in this region. We therefore hypothesise that plastics "beach" and end up on coastlines along the Indian Ocean rim. In this paper, we determine the influence of beaching plastics by applying different beaching conditions to Lagrangian particle tracking simulation results. Our results show that a large amount of plastic likely ends up on coastlines in the NIO, while some crosses the equator into the southern hemisphere Indian Ocean (SIO). In the NIO, the transport of plastics is dominated by seasonally reversing monsoonal currents, which transport plastics back and forth between the Arabian Sea and the Bay of Bengal. All buoyant plastic material in this region beaches within a few years in our simulations. Countries bordering the Bay of Bengal are particularly heavily affected by plastics beaching on coastlines. This is a result of both the large sources of plastic waste in the region, as well as ocean dynamics which concentrate plastics in the Bay of Bengal. During the intermonsoon period following the southwest monsoon season (September, October, November), plastics can cross the equator on the eastern side of the NIO basin into the SIO. Plastics that escape from the NIO into the SIO beach on eastern African coastlines and islands in the SIO or enter the subtropical SIO garbage patch.

scholarly journals Intra-seasonal oscfffations of radio refractive index during southwest monsoon over India

MAUSAM ◽  
2022 ◽  
Vol 44 (3) ◽  
pp. 271-276
Author(s):  
H. N. SRIVASTAVA ◽  
K. C. SINHARAY ◽  
R. K. MUKHOPADHYAY
Keyword(s):  
Refractive Index ◽  
Monsoon Season ◽  
Temporal Variations ◽  
Southwest Monsoon ◽  
The Individual ◽  
Southwest Monsoon Season ◽  
Seasonal Oscillations ◽  
Refractive Index Data ◽  
Indian Seas ◽  
Variance Explained

The study deals with the spatial and temporal variations of intra-seasonal oscillations in radio refractive index during southwest monsoon season over India and islands over Indian seas. Average daily radio refractive index data from 1 June to 30 September and that of the individual years for the period 1969-1986 were subjected to harmonic analysis to investigate the contributions of various periodicities in monsoon radio refractive index. The inter-annual variability of various intra-seasonal oscillations have been studied for each 5° latitudinal strip from 50 oN to 30° N with the help of variance explained by various frequency modes for different years. Variance explained by 30-60 day and 10-20 day modes were studied in relation to monsoon performance.   The northward and eastward propagation of30.60 day mod~ was noticed. The 10.20 day mode and seasonal mode dominate at latitudinal belts 5°N.10oN and 25°N-30°N respectively. Between 10°N and 25°N, both 30-60 day and 10-20 day modes occur.  

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