Forecasting of Summer Monsoon Rainfall over Gangetic West Bengal, India Utilising Intrinsic Mode Functions, Linear and Neural Regression

2020 ◽  
Vol 12 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Pijush Basak
Keyword(s):  
Neural Network ◽  
West Bengal ◽  
Monsoon Rainfall ◽  
Linear Part ◽  
Intrinsic Mode Functions ◽  
Quasi Biennial Oscillation ◽  
Nonlinear Part ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon

The South West Monsoon rainfall data of the meteorological subdivision number 6 of India enclosing Gangetic West Bengal is shown to be decomposable into eight empirical time series, namely Intrinsic Mode Functions. This leads one to identify the first empirical mode as a nonlinear part and the remaining modes as the linear part of the data. The nonlinear part is modeled with the technique Neural Network based Generalized Regression Neural Network model technique whereas the linear part is sensibly modeled through simple regression method. The different Intrinsic modes as verified are well connected with relevant atmospheric features, namely, El Nino, Quasi-biennial Oscillation, Sunspot cycle and others. It is observed that the proposed model explains around 75% of inter annual variability (IAV) of the rainfall series of Gangetic West Bengal. The model is efficient in statistical forecasting of South West Monsoon rainfall in the region as verified from independent part of the real data. The statistical forecasts of SWM rainfall for GWB for the years 2012 and 2013 are108.71 cm and 126.21 cm respectively, where as corresponding to the actual rainfall of 93.19 cm 115.20 cm respectively which are within one standard deviation of mean rainfall.

The Impact of PDO on South–West Monsoon Rainfall Over Sri Lanka and Monsoon-ENSO Relation

2021 ◽  
pp. 171-183
Author(s):  
R. D. Hettiarachchi ◽  
W. L. Sumathipala ◽  
W. C. W. Navaratna ◽  
S. Somarathne ◽  
K. H. M. S. Premalal
Keyword(s):  
Sri Lanka ◽  
Monsoon Rainfall ◽  
South West ◽  
South West Monsoon ◽  
The Impact ◽  
West Monsoon

Some features of the south-west monsoon rainfall of Cochin and Minicoy

1987 ◽  
Vol 7 (4) ◽  
pp. 355-372 ◽  
Author(s):  
R. Ananthakrishnan ◽  
C. K. Kajan
Keyword(s):  
Monsoon Rainfall ◽  
The South ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon

scholarly journals Forecasting of Indian south-west monsoon rainfall

2001 ◽  
Vol 8 (2) ◽  
pp. 245-252 ◽  
Author(s):  
K Bhaskara Rao ◽  
C V Naidu ◽  
O S R U Bhanukumar
Keyword(s):  
Monsoon Rainfall ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon

scholarly journals Eastern and North Eastern sub-divisions of India : An analysis of trend and chaotic behaviour of rainfall in different seasons

MAUSAM ◽  
2021 ◽  
Vol 71 (4) ◽  
pp. 625-636
Author(s):  
BASAK PIJUSH
Keyword(s):  
Lyapunov Exponent ◽  
West Bengal ◽  
Monsoon Season ◽  
Chaotic Behaviour ◽  
Annual Rainfall ◽  
North East ◽  
South West ◽  
South West Monsoon ◽  
North Eastern ◽  
West Monsoon

The aim of the study is to understand trend or non-linearity along with a chaotic behaviour, if any, of Eastern and North Eastern sub-divisional rainfall, namely Orissa, Gangetic West Bengal, Sub Himalayan West Bengal, Assam and Meghalaya and also Nagaland, Manipur, Mizoram and Tripura based on rainfall data of 143 years (1871-2013). The analysis is performed for examining behaviour of rainfall in each of the seasons, namely, Pre monsoon, South West monsoon, North East monsoon and also Annual rainfall extracted from the monthly data. For that purpose, a trend analysis with Hurst Exponent and non-linearity analysis with Lyapunov Exponent are employed. The analysis revealed that rainfall of Orissa is persistent for all the seasons whilst the rainfall is persistent in Gangetic West Bengal in Pre monsoon and North East monsoon and Assam and Meghalaya along with Nagaland, Manipur, Mizoram and Tripura exhibit persistent behaviour in South West Monsoon and annually. Sub Himalayan West Bengal exhibit persistence in annual rainfall only. Chaotic tendency in low magnitude is located in many cases whilst non-chaotic situation has occurred when the persistence is found, mainly in pre-monsoon season. Moreover, the analysis of Hurst and Lyapunov Exponent revealed to identify two groups of sub-divisions with exactly similar region of every respect. Those two groups contain (i) sub-divisions Orissa and Assam and Meghalaya and also (ii) sub-divisions Sub Himalayan West Bengal and Nagaland, Mizoram, Manipur and Tripura although those are at distances of hundreds of kilometers away. The behaviour of those subdivisions in a group has similar behaviour in all respects.

Recurrent landslides in Southern Western Ghats, India: A changing environmental perspective

2021 ◽  
Author(s):  
Asokan Laila Achu ◽  
Girish Gopinath
Keyword(s):  
Western Ghats ◽  
Hot Spot ◽  
Extreme Rainfall ◽  
Vital Role ◽  
Monsoon Period ◽  
Extreme Rainfall Events ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon ◽  
The Western Ghats

<p>The Western Ghats (WG), an elevated passive continental margin along the southwestern coast of India, is the most widely populated biodiversity hot spot in the world. Monsoon climate is prevalent throughout the length of the Western Ghats. The WG region is prone to the occurrence of various hydro-climatic disasters such as extreme rainfall-driven floods and landslides. During the past 100 years, landslides and floods caused by extreme rainfall events in the WG have occurred in 1924 and 1979; but the most disastrous event, in terms of area of impact, loss of life and economic impact, occurred in August 2018. Generally, the south-west monsoon (Indian summer monsoon) occurs in the first week of June and extends up to September and the Indian Meteorological Department (IMD) predicted above-normal rainfall of 13% during the month of August 2018. But the State received an excess of 96% during the period from 1st to 30th August 2018, and 33% during the entire monsoon period till the end of August. The unprecedented heavy rains, storms, floods and associated thousands of landslides have caused exorbitant losses including 400 life losses, over 2.20 lakh people were displaced, and 20000 homes and 80 dams were damaged or destructed. This study aimed to elucidate the reasons behind the thousands of landslides caused in WG using observed and field evidences. Changes in south-west monsoon pattern and rainfall intensity played a vital role in the occurrence of landslides in WG. Further, the extensive causalities are the result of anthropogenic disturbances including landscape alterations and improper landuse practices in the hilly tracks of WG. The major causative factors for series of landslides in various segments of WG is due to hindrance of lower order streams/springs, vertical cutting, intensive quarrying, unscientific rain pits & man-made structures together with erratic rainfall triggered major and minor landslides in various segments of WG. The present investigation concludes that a scientific landuse policy and geoscientific awareness is essential to mitigate the environment.</p>

scholarly journals The Theory of the South-West Monsoon

Nature ◽  
1922 ◽  
Vol 109 (2726) ◽  
pp. 109-112
Author(s):  
L. C. W. BONACINA
Keyword(s):  
The South ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon

scholarly journals Strong CO2emissions from the Arabian Sea during south-west monsoon

1997 ◽  
Vol 24 (14) ◽  
pp. 1763-1766 ◽  
Author(s):  
Arne Körtzinger ◽  
Jan C. Duinker ◽  
Ludger Mintrop
Keyword(s):  
Arabian Sea ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon
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