On the origin of the cold weather storms of the year 1893 in India, and the character of the air movement on the Indian seas and Teie: Equatorial belt, more especially during the South-West monsoon period (as shown by the data of tee Indian monsoon area c

<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>

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Influence of winds on temporally varying short and long period gravity waves in the near shore regions of Eastern Arabian Sea

Ocean Science Discussions ◽

10.5194/osd-9-3021-2012 ◽

2012 ◽

Vol 9 (5) ◽

pp. 3021-3047

Author(s):

J. Glejin ◽

V. Sanil Kumar ◽

T. N. Balakrishnan Nair ◽

J. Singh

Keyword(s):

West Coast ◽

Sea Breeze ◽

Monsoon Period ◽

West Coast Of India ◽

Intermediate Period ◽

Long Period ◽

Post Monsoon ◽

South West ◽

South West Monsoon ◽

West Monsoon

Abstract. Wave data collected off Ratnagiri, west coast of India during 1 May 2010 to 30 April 2012 is used in the study. Seasonal and annual variation in wave data controlled by the local wind system such as sea breeze and land breeze, and remote wind generated long period waves observed along the west coast of India, is studied. Sea breeze plays an important role in determining the sea state during pre and post monsoon seasons and the maximum wave height is observed during peak hours of sea breeze at 15:00 UTC. Long period waves (peak period over 13 s) are observed mainly during the pre and the post monsoon season. Maximum peak period observed during the study is 22 s and is in the month of October. Long period waves observed during the south west monsoon period of 2011 are identified as swell propagated from the Southern Ocean with an estimated travelling time of 5–6 days. The swells reaching the Arabian Sea from the South Indian Ocean and Southern Ocean, due to storms during the pre and post monsoon periods will modify the near surface winds, due to the dominant wave induced wind regime. Energy spectrum of observed waves indicates onset and decline of strong south west monsoon winds. Convergence of energy-containing frequency bands corresponding to short period waves (Tp < 8 s) and long period waves (Tp > 13 s) to intermediate period waves (8 < Tp < 13 s) are observed at the end of the pre monsoon season; divergence is observed during the start of the post monsoon period from intermediate period waves to short period waves and long period waves. South west monsoon period is characterized by the energy corresponding to the frequency band of intermediate period waves along the west coast of India.

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Seasonal foraging activity of stingless bee Tetragonula travancorica Shanas and Faseeh (Hymenoptera: Apidae: Meliponini)

ENTOMON ◽

10.33307/entomon.v46i2.601 ◽

2021 ◽

Vol 46 (2) ◽

pp. 149-166

Author(s):

Lincy Abraham ◽

S. Shanas

Keyword(s):

Weather Conditions ◽

Southwest Monsoon ◽

Stingless Bee ◽

Foraging Activity ◽

Monsoon Period ◽

North East ◽

South West ◽

South West Monsoon ◽

Two Peaks ◽

West Monsoon

The foraging hive activity of stingless bee Tetragonula travancorica Shanas and Faseeh was studied from November 2018 to August 2019. The activity varied between the seasons, weather conditions and time hours of study. The outgoing and incoming pollen foragers exhibited two peaks in activity, from 0800-1200 h (first) and during 1500-1600 h (second). The activity of incoming non-pollen foragers displayed only one distinct peak between 1000-1200 h except during the southwest monsoon period. The greatest activity was recorded during the dry season (January-May), followed by the south-west monsoon (June-August) and north-east monsoon (November- December) seasons. Maximum overall activity was recorded during hotter months February, March and April while the lowest was observed in January and December. At any season or time, the number of incoming foragers without pollen was greater than pollen foragers.

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Art. XIII.—A remarkable Appearance in the Indian Seas; in a Letter from Lieutenant Dawson

Journal of the Royal Asiatic Society ◽

10.1017/s0035869x00015239 ◽

1838 ◽

Vol 5 (9) ◽

pp. 198-200

Author(s):

H. D.

Keyword(s):

Persian Gulf ◽

Royal Navy ◽

The South ◽

South West ◽

South West Monsoon ◽

The Persian Gulf ◽

West Monsoon ◽

Indian Seas

I beg leave to lay before the meeting an extract from the private journal of Lieutenant Henry Dawson, a very intelligent officer of the Royal Navy, at present employed on civil duties with the Indian Navy at Bombay, containing an account of a very extraordinary phenomenon, which was observed on the passage from Bombay to the Persian Gulf (the southern passage), on board the Honourable Company's sloop of war Clive, in 1832. On my first going to India, I was in the habit of intimacy with the late Captain David Seton, who was many years Resident at Muscat, and I well remember hearing him relate the circumstance of falling in with the while sea, described by Mr. Dawson, on his occasional voyages to Muscat, during the period of the south-west monsoon. So many years, however, have since elapsed, I am unable to give any more detail of the circumstance related by that officer, and merely here allude to it in proof of the phenomenon having been before observed.

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Inertia-gravity waves associated with the tropical easterly jet over the Indian subcontinent during the South West Monsoon Period

Geophysical Research Letters ◽

10.1029/1999gl011216 ◽

2000 ◽

Vol 27 (19) ◽

pp. 3201-3204 ◽

Cited By ~ 14

Author(s):

M. N. Sasi ◽

Geetha Ramkumar ◽

V. Deepa ◽

B. V. Krishna Murthy

Keyword(s):

Gravity Waves ◽

Indian Subcontinent ◽

The South ◽

Monsoon Period ◽

South West ◽

Tropical Easterly Jet ◽

South West Monsoon ◽

West Monsoon ◽

Inertia Gravity Waves

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

Journal of Modeling and Optimization ◽

10.32732/jmo.2020.12.1.60 ◽

2020 ◽

Vol 12 (1) ◽

pp. 60-69 ◽

Cited By ~ 1

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.

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