scholarly journals Performance of WRF’S Microphysics Options to Increase the Medium Range Rainfall Forecast Accuracy in Tamil Nadu Cauvery Delta Zone

2020 ◽  
pp. 511-518
Author(s):  
S. Poorani Selvi ◽  
G. A. Dheebakaran ◽  
S. Kokilavani ◽  
V. Geethalakshmi
Keyword(s):  
Tamil Nadu ◽  
Forecast Accuracy ◽  
Cost Ratio ◽  
North East ◽  
South West ◽  
Rainfall Forecast ◽  
South West Monsoon ◽  
Medium Range ◽  
Cauvery Delta ◽  
West Monsoon

Weather plays a significant role in agricultural sector and the favourable weather enhance the opportunities and sustainability for crop production. Agriculture oriented Medium Range Weather Forecasts (3 – 10 days), particularly rainfall information in a week advance helps the farmers to overcome the aberrant weather conditions, reduces both input and output loss, thereby warranted higher benefit – cost ratio and net income. An attempt was made to improve the accuracy of medium range rainfall forecast (6 days) at Cauvery Delta Zone, the rice bowl of Tamil Nadu state, during South West Monsoon (June – Sep. 2020) and North East Monsoon (Oct. – Dec. 2020). The performance study of four microphysics schemes in WRF viz., Kessler, WSM3, WSM5 and WSM6 concluded that the WSM3 scheme produced more accurate forecast in Tamil Nadu's Cauvery Delta Zone (CDZ) during both the South West Monsoon (SWM) and North East Monsoon (NEM). The 2nd better choice was the Kessler scheme, where the WSM5 and WSM6 were bad performers in CDZ. The forecast usability was decreased with increasing lead time, irrespective of season and microphysics. Among the seasons forecast accuracy and usability were higher in NEM than SWM.

scholarly journals Spatial and Temporal Assessment of Rainfall Variability using GIS Approach in Trichy District of Tamil Nadu

2021 ◽  
Vol 16 (3) ◽  
pp. 890-897
Author(s):  
P. Ponnuchakkammal P. Ponnuchakkammal ◽  
B. Violet Joy ◽  
P. Aravind ◽  
A. Raviraj A. Raviraj
Keyword(s):  
Tamil Nadu ◽  
Hydrological Cycle ◽  
Rainfall Variability ◽  
Geographical Information ◽  
Annual Rainfall ◽  
Maximum Rainfall ◽  
North East ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon

Precipitation is one of the transportation components in hydrological cycle. The magnitude of precipitation swings with time and space. Majorly India receives precipitation in the form of rainfall. Precipitation plays a key role in the rainfed agriculture. The present study deals with the rainfall characteristics of Tiruchirappalli district, Tamil Nadu. Seasonal rainfall data from eighteen rain gauge stations (1971-2012) have been taken for analysis of seasonal and annual rainfall pattern of Tiruchirappalli district. Mean rainfall of the district is about 696 mm. The highest rainfall of 1247 mm recorded in the year 2005 and the lowest precipitation of 227 mm recorded in the year 1976. About 48 percent and 35 percent of the rainfall received in North East and South West Monsoon, respectively. Spatial rainfall distribution was studied with the help of Kriging interpolation technique and respective maps were prepared with Geographical Information System. The percentage departure of annual rainfall is classified under the category of excess, normal and large excess category. South East and central part of Tiruchirappalli receives moderate to low rainfall. North East parts of Tiruchirappalli district such as pullambadi, Lalgudi and nearby areas received maximum rainfall during North East Monsoon and South West Monsoon. In winter season Manapparai and Vaiyampatti region received more rainfall while in summer season Thottiam and Mayanur area received more rainfall. The two major highlighted crops in Trichy district are Banana and Onion. Tiruchirappalli district is one of the Banana growing belts in Tamil Nadu. Spatial distribution of rainfall maps will be helpful to form a crop plan for different crops to increase the agricultural productivity of Tiruchirappalli district and to ensure the food security.

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 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. 

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.

scholarly journals CLOUD BURST DURING SOUTH WEST MONSOON SEASON AT TIRUCHIRAPALLI, TAMIL NADU

MAUSAM ◽  
2021 ◽  
Vol 62 (2) ◽  
pp. 253-256
Author(s):  
E. KULANDAIVELU ◽  
M. SOUNDARARAJ ◽  
M.V. GUHAN
Keyword(s):  
Tamil Nadu ◽  
Monsoon Season ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon

scholarly journals Monsoon Agriculture - Suggestieve Methods Using Dependable Inflow & Rainfall for a Command Area

2018 ◽  
Vol 7 (3.12) ◽  
pp. 729
Author(s):  
S Surianarayanan ◽  
S Jaya kumar ◽  
S Jeyaprakash
Keyword(s):  
Tamil Nadu ◽  
Water Requirement ◽  
Command Area ◽  
Agricultural Field ◽  
North East ◽  
The North ◽  
South West Monsoon ◽  
West Monsoon ◽  
Kendall Method

In the recent trend of changing environment, the rainfall and the inflow to the reservoir are getting reduced year by year respectively in agricultural field and in river basins. In this paper the dependable inflow into the reservoir and the rainfall in the command area is estimated with the past 30 years data. The statistical methods and formulae (Variance, Mann- Kendall method) are used to determine the dependable inflow and rainfall for both the monsoons. It is found that the inflow is not dependable for South –West monsoon, to do the agriculture, for a normal crop, with medium water requirement.. For the North - East monsoon both the inflow and rainfall are dependable hence the agriculture can be carried out with a single crop (paddy) having more water requirement (or) possible multi-crops, according to the storage in the reservoir and prediction of rainfall in that season. The deductions for other requirements of the dam, losses for evaporation, conveyance etc has been taken into account. The case study is done with the data for 30 years (1982-2012)for a dam in Tamil Nadu, India. 

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.

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.

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

&lt;p&gt;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 &amp; 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.&lt;/p&gt;

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