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

ENTOMON ◽  
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.

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 An Experiment in Weather Prediction for North East and South West Monsoon Over Chennai

2019 ◽  
Vol 8 (3) ◽  
pp. 4460-4465
Keyword(s):  
Weather Prediction ◽  
Rule Mining ◽  
Local Data ◽  
Coastal Station ◽  
North East ◽  
South West ◽  
South West Monsoon ◽  
Using Data ◽  
West Monsoon ◽  
Regional Forecast

There is a growing demand for spot specific forecast. Presently this has to be extracted from the regional forecast based on synoptic models. Synoptic models require input from various observatories of regions or the country and the central analysis centre is required for generating the synoptic charts. But recently the authors have established the potential of local data alone as a continuous time scale for use in effective local forecast using data mining techniques. Following the same association rule mining and classifier approach is tried for the forecast of wet and dog days on North East Monsoon and South West Monsoon months for the Chennai region with Latitude 13°11' N and Longitude 80°11' E, a coastal station over Bay of Bengal in South India and results are presented.

scholarly journals Filamentous cyanobacteria from western ghats of North Kerala, India

2021 ◽  
Vol 28 (1) ◽  
pp. 83-95
Author(s):  
V Geethu ◽  
Mamiyil Shamina
Keyword(s):  
Western Ghats ◽  
New Records ◽  
Filamentous Cyanobacteria ◽  
North East ◽  
South West ◽  
South West Monsoon ◽  
Plant Taxon ◽  
Kerala State ◽  
West Monsoon ◽  
Cyanobacterial Genus

Cyanobacteria are Gram negative, photosynthetic and nitrogen fixing microorganisms which contribute much to our present-day life as medicines, foods, biofuels and biofertilizers. Western Ghats are the hotspots of biodiversity with rich combination of microbial flora including cyanobacteria. Though cosmopolitan in distribution, their abundance in tropical forests are not fully exploited. To fill up this knowledge gap, the present research was carried out on the cyanobacterial flora of Peruvannamuzhi forest and Janaki forests of Western Ghats in Kozhikode District, North Kerala State, India. Extensive specimen collections were conducted during South-West monsoon (June to September) and North-East monsoon (October to December) in the year 2019. The highest diversity of cyanobacteria was found on rock surfaces. A total of 18 cyanobacterial taxa were identified. Among them filamentous heterocystous forms showed maximum diversity with 10 species followed by non- heterocystous forms with 8 species. The highest number of cyanobacteria were identified from Peruvannamuzhi forest with 15 taxa followed by Janaki forest with 3 taxa. The non- heterocystous cyanobacterial genus Oscillatoria Voucher ex Gomont showed maximum abundance with 4 species. In this study we reported Planktothrix planktonica (Elenkin) Agagnostidis & Komárek 1988, Oscillatoria euboeica Anagnostidis 2001 and Nostoc interbryum Sant’Anna et al. 2007 as three new records from India. Bangladesh J. Plant Taxon. 28(1): 83-95, 2021 (June)

scholarly journals Present operational long range forecasting system for southwest monsoon rainfall over India and its performance during 2010

MAUSAM ◽  
2021 ◽  
Vol 62 (2) ◽  
pp. 179-196
Author(s):  
D.S. PAI ◽  
O.P. SREEJITH ◽  
S.G. NARGUND ◽  
MADHURI MUSALE ◽  
AJIT TYAGI
Keyword(s):  
Monsoon Season ◽  
Central India ◽  
Southwest Monsoon ◽  
Northeast India ◽  
Peninsular India ◽  
South West ◽  
Operational Forecasts ◽  
Geographical Regions ◽  
South West Monsoon ◽  
West Monsoon

At present, India Meteorological Department (IMD) issues various monthly and seasonal operational forecasts for the south-west monsoon season using models based on latest statistical techniques with useful skill. Operational models are reviewed regularly and improved through in house research activities. For the forecasting of the south-west monsoon season (June – September) rainfall over the country as a whole, a newly introduced statistical ensemble forecasting system is used. In addition, models have been developed for the forecast of the monsoon season rainfall over four geographical regions (NW India, NE India, Central India and South Peninsula) of the country and forecast for the rainfall over the second half of the monsoon season over the country as a whole. Models have also been developed for issuing operational forecast for the monthly rainfall for the months of July, August & September over the country as a whole. Operational forecasts issued by IMD for 2010 south-west monsoon rainfall have been discussed and verified. In addition, the experimental forecasts for the season rainfall over the country as a whole based on bothstatistical and dynamical models received from various climate research institutes within the country other than IMD arealso discussed. The operational monthly and seasonal long range forecasts issued for the 2010 southwest monsoon season for the country as a whole were accurate. However, forecasts for the season rainfall over the 4 geographical regions (Northwest India, Central India, Northeast India and south Peninsular India) were not accurate as the forecast for South Peninsular India overestimated the actual rainfall and that for northeast India underestimated the actual rainfall. The experimental forecasts for the season rainfall over the country as whole from various climate research institutes within the country showed large variance (91 % - 112% of LPA).

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

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.

scholarly journals Stream flow trends in up and midstream of Kirindi Oya river basin in Sri Lanka and its linkages to rainfall

MAUSAM ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 99-110
Author(s):  
N. S. ABEYSINGHA ◽  
J. M. N. S. JAYASEKARA ◽  
T. J. MEEGASTENNA
Keyword(s):  
River Basin ◽  
Agricultural Production ◽  
Early Onset ◽  
Stream Flow ◽  
North East ◽  
South West ◽  
South West Monsoon ◽  
Increasing Trend ◽  
West Monsoon ◽  
Polygon Method

Trend analysis of hydro-climatic variables provide useful information for effective planning, designing and management of water resources and agricultural production. Trends in observed stream flow at upstream and midstream gauging stations (GS), Wellawaya, Thanamalwila & rainfall and temperature in the Kirindi Oya river basin were assessed using the Mann-Kendall, Modified Mann-Kendall and Sen’s slope. Average rainfalls for the two catchments and for the entire basin were computed using ‘Thessen polygon’ method. The relationships between trends in stream flow and catchment rainfall were studied by Spearman’s Rho correlation coefficient .   Five year Moving averaged Standardize Anomalies (FMSA) of both annual stream flow and rainfall at Wellawaya and Thanamalwila catchments were in a non-significant (p < 0.05) decreasing trend for 1994 to 2010.Though there was a positive correlation between annual catchment rainfall and stream flow of these two catchments, correlation was significant (p < 0.05) only at Thanamalwila (0.69) suggesting that the variation of annual stream flow at Thanamalwila GS was mainly attributed to the variation of catchment rainfall. However, variation of stream flow during North East Monsoon (NEM) season was mainly attributed to the variation of respective catchment rainfall of both the catchments as evident by significant higher ‘p’ at  Wellawaya (0.61) and Thanamalwila (0.69). This study also found that trend of FMSA of South West Monsoon (SWM) rain was significantly (p < 0.05) decreasing for the entire basin, Thanamalwila and Wellawaya  sub-catchments. Stream flow at Wellawaya GS during SWM was also found to be significantly decreasing while Thanamalwila stream flow was non-significantly decreasing. Both rainfall and stream flow during First Inter Monsoon (FIM) was in a significant increasing trend particularly in the month of April. These observed trends during SWM and FIM suggest an apparent early onset of SWM in the basin, or drastic deviation in receiving rain during SWM in the Kirindi Oya river basin. 

INDIAN MONSOON: IN THE CONTEXT OF CURRENT

2020 ◽  
Vol 5 (12) ◽  
pp. 318-321
Author(s):  
Chandra kanta Sharma
Keyword(s):  
Indian Subcontinent ◽  
Southwest Monsoon ◽  
The South ◽  
South West ◽  
South West Monsoon ◽  
Average Rainfall ◽  
The Indian Ocean ◽  
Monsoon Winds ◽  
Northwest Region ◽  
West Monsoon

The monsoon in India is called the summer winds which are active in South Asia from June to September. These winds flow from the Indian Ocean, the Bay of Bengal and the Arabian Sea towards the Indian subcontinent. Their direction is towards the south-west and south-north, hence the monsoon winds are also known as the south-west monsoon winds. The southwest monsoon provides 70% of the total rainfall in the country. But this year, the country has received less than average rainfall, which was 5.2%. The northwest region of the country recorded the highest decrease of 10 percent. After good rainfall in June and July, the monsoon in the country remained weak during August and September.   भारत में मानसून उन ग्रीष्मकालीन हवाओं को कहते हैं जो दक्षिण एशिया में जून से सितंबर तक सक्रिय रहती हैं। ये हवाएं हिन्दमहासागर, बंगाल की खाड़ी और अरबसागर से भारतीय उपमहाद्वीप की ओर प्रवाहित होती है। इनकी दिशा दक्षिण-पश्चिम और दक्षिण-उत्तर की ओर होती है अतः मानसूनी हवाओं को दक्षिण-पश्चिम मानसूनी हवाओं के नाम से भी जाना जाता है। दक्षिण-पश्चिम मानसून देश में कुल वर्षा का 70% भाग प्रदान करता है। लेकिन इस वर्ष देश में औसत से कम वर्षा दर्ज की गई है संपूर्ण देश में 5.2% की कमी रही। देश के उत्तर – पश्चिम क्षेत्र में सबसे अधिक 10 फीसद की कमी दर्ज की गई। जून और जुलाई में अच्छे वर्षा के बाद अगस्त और सितंबर के दौरान देश में मानसून कमजोर रहा।

scholarly journals DESIGN AND BEHAVIOUR OF SANDTRAPS IN REGIONS OP HIGH LITTORAL DRIFT

1976 ◽  
Vol 1 (15) ◽  
pp. 80
Author(s):  
P.C. Sarena ◽  
P.P. Vaidyaraman ◽  
R. Srinivasan
Keyword(s):  
Wave Action ◽  
Eastern Coast ◽  
Littoral Drift ◽  
Monsoon Period ◽  
Large Wave ◽  
North East ◽  
South West ◽  
South West Monsoon ◽  
Approach Channel ◽  
Maintenance Dredging

Siltation in harbours and their approach channels is one of the major problems connected with the development of harbours. The economics of harbours are directly related to their annual maintenance dredging, and as such a proper assessment of the quantity of siltation and provision of adequate measures for the maintenance of depths would form an important part of planning the development programmes. Siltation could occur due to various reasons viz. deposition of littoral drift which is interrupted by the approach channel, deposition of sediments brought into suspension by wave action (including during storm/cyclone) Whenever the alongshore drift is large, wave action obviously is quite substantial which renders the maintenance of depths during this period by dredging difficult. In such cases it would be necessary to make adequate provision to ensure that the depths are not deteriorated to any substantial extent by the movement of the drift. One of the common means for achieving this is the provision of sandtraps on the updrlft side of the approach channel which would 'store' the drift material temporarily and from where the material could be dredged at convenience. The design of the sandtrap would be governed by a number of factors such as the extent over which a major part of the drift takes place, quantity of material transported, size distribution of sediments, velocity of currents, mode of dredging etc. Waves of moderate to high intensity occurs along the eastern coast of India from south and south west direction during south west monsoon period from May to September and from North Easterly direction during North East monsoon beginning from November. In view of this climate the direction of drift along the shore changes with Mason. The quantities of drift during these periods are also different owing to the magnitudeand periods of wave action which differs between the two seasons. The net drift along this coast varies from 0»60 million m3 at Madras on the south which increases progressively to 1,00 million m3 at Paradip further North (Fig, 1),

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