scholarly journals Rainfall Variability and Trend Detection in Dindigul District of Amaravathi Basin

2016 ◽  
Vol 11 (2) ◽  
pp. 567-576 ◽  
Author(s):  
S Thangamani ◽  
A Raviraj
Keyword(s):  
Monsoon Season ◽  
Rainfall Variability ◽  
Southwest Monsoon ◽  
Trend Detection ◽  
Annual Rainfall ◽  
Maximum Rainfall ◽  
North East ◽  
The North ◽  
South West Monsoon ◽  
West Monsoon

The present study attempted to find out the relation between rainfall variability, trend and distribution in Dindigul district of Amaravathi basin for groundwater management. A detailed analysis of monthly, seasonal and spatial variation of rainfall (1971-2014) for the study area had carried out. The normal annual rainfall of the district varies from 700 to 1600 mm. The north east monsoon contributed the maximum rainfall of 439mm (50%), followed by South-west monsoon which contributed 254 mm (29%), summer which contributed 147 mm (16.8%) and winter contributed the minimum rainfall of 26.8 mm (2.8%).A high value of CV had observed in all the stations, which indicate the greater rainfall variability, and more chances of occurrence of drought. Higher variability of coefficient of variation was observed in central part of the district.Theresult of MMK z-test at 1% level indicates that the majority of stations showed non-significant trend in annual, summer and monsoon season of rainfall. Out of the 13 stations studied in the district, annual rainfall of only one station (Kuthiraiyar) showed significant decreasing trend in annual rainfall (-3.05 mm/year) and five stations recorded the significant decreasing trend in rainy days during southwest monsoon. Chatrapatti and Natham stations recorded the significant increasing trend during north east monsoon and Virupatchi station recorded the decreasing trend.

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 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.

scholarly journals Analysis of Rainfall Probabilities for Strategic Crop Planning in Raipur District of Chhattisgarh State

2015 ◽  
Vol 10 (1) ◽  
pp. 253-257
Author(s):  
Sanjay Bhelawe ◽  
M Manikandan ◽  
Rajesh Khavse ◽  
J Chaudhary ◽  
S Patel
Keyword(s):  
Monsoon Season ◽  
Winter Season ◽  
Probability Level ◽  
North East ◽  
Rainfed Rice ◽  
South West Monsoon ◽  
Average Rainfall ◽  
Seasonal Basis ◽  
Average Condition ◽  
West Monsoon

Rainfall data of recent forty three years (1971-2013) of Labhandi station, Indira Gandhi Krishi Vishwavidhyalaya Raipur, Chhattisgarh was analysed with the method of incomplete gamma probability. The data revealed that the average rainfall of labhandi station is 1202 mm spread over 61 rainy days. Out of this 1055, 68, 53 and 27 mm received from south west monsoon (June-September), north east (October-December), summer (March-May) and winter season (January -February) respectively. Probability for receiving more than 100 mm of rainfall can be expected only at 25% probability level and that too in four weeks which is leading to the interpretation that rainfed rice production is a challenging task in this region. it has been found that at 75 per cent assured probability level rainfall of more than 200 mms can be expected only in July and August months and this rainfall is hardly sufficient for meeting the water requirement in upland situations. However at 50 per cent probability which is equivalent to average condition, cultivation of rice is possible under well water management conditions. On seasonal basis rainfall at assured probability level of 75% is not sufficient as the quantity is 795 mm rainfall in south-western monsoon season.

scholarly journals Analysis of rainfall trends over Tripura

MAUSAM ◽  
2022 ◽  
Vol 73 (1) ◽  
pp. 27-36
Author(s):  
RANJAN PHUKAN ◽  
D. SAHA
Keyword(s):  
Heavy Rainfall ◽  
Monsoon Season ◽  
Rainfall Variability ◽  
Kendall Test ◽  
Annual Rainfall ◽  
The North ◽  
Rainfall Trends ◽  
Annual Scale ◽  
Increasing Trends ◽  
Rainy Days

Rainfall in India has very high temporal and spatial variability. The rainfall variability affects the livelihood and food habits of people from different regions. In this study, the rainfall trends in two stations in the north-eastern state of Tripura, namely Agartala and Kailashahar have been studied for the period 1955-2017. The state experiences an annual mean of more than 2000 mm of rainfall, out of which, about 60% occurs during the monsoon season and about 30% in pre-monsoon. An attempt has been made to analyze the trends in seasonal and annual rainfall, rainy days and heavy rainfall in the two stations, during the same period.Non-parametric Mann-Kendall test has been used to find out the significance of these trends. Both increasing and decreasing trends are observed over the two stations. Increasing trends in rainfall, rainy days and heavy rainfall are found at Agartala during pre-monsoon season and decreasing trends in all other seasons and at annual scale. At Kailashahar, rainfall amount (rainy days & heavy rainfall) is found to be increasing during pre-monsoon and monsoon seasons (pre-monsoon season). At annual scale also, rainfall and rainy days show increasing trends at Kailashahar. The parameters are showing decreasing trends during all other seasons at the station. Rainy days over Agartala show a significantly decreasing trend in monsoon, whereas no other trend is found to be significant over both the stations.  

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 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).

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.

Influence of Sea Level Pressure on inter-annual rainfall variability in northern Senegal in the context of climate change

2021 ◽  
Author(s):  
Aichetou Dia Diop ◽  
Malick Wade ◽  
Sinclaire Zebaze ◽  
Abdoulaye Bouya DIOP ◽  
Eric Efon ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Sea Level ◽  
Rainfall Variability ◽  
Empirical Orthogonal Functions ◽  
Annual Rainfall ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
North East ◽  
The North ◽  
Pressure Area

Abstract This study examines the inter-annual variability of rainfall and mean Sea Level Pressure (SLP) over west Africa based on analysis of the Global Precipitation Climatology Project (GPCP) and National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis respectively. An interconnection is found in this region, between MSLP anomaly (over Azores and St. Helena High) and monthly mean precipitation during summer (June to September: JJAS). We also found that over northern Senegal (15°N-17°N; 17°W-13°W) the SLP to the north is strong; the wind converges at 200hPa corresponding to the position of the tropical Easterly jet (TEJ); the rotational wind 700hPa (corresponding to the position of the AEJ) coming from the north-east is negative. In this region, the precipitation is related to the SLP to the north with the opposite sign. The empirical orthogonal functions (EOF) of SLP are also presented, including the mean spectrum of precipitation and pressures to the north (15°N-40°N and 50°W-25°W) and south (40°S-10°S and 40°W-0°E). The dominant EOF of Sea Level Pressures north and south of the Atlantic Ocean for GPCP represents about 62.2% and 69.4% of the variance, respectively. The second and third EOFs of the pressure to the north account for 24.0% and 6.5% respectively. The second and third EOFs of the pressure to the south represent 12.5% and 8.9% respectively. Wet years in the northern of Senegal were associated with anomalous low-pressure area over north Atlantic Ocean as opposed to the dry years which exhibited an anomalous high-pressure area in the same region. On the other hand, over south Atlantic, an opposition is noted. The wavelet analysis method is applied to the SLP showings to the north, south and precipitation in our study area. The indices prove to be very consistent, especially during intervals of high variance.

scholarly journals Trend Analysis of Rainfall Variability in Western Agro Climatic Zone of Tamil Nadu

2017 ◽  
Vol 12 (1) ◽  
pp. 181-187 ◽  
Author(s):  
S Kokilavani ◽  
R Selvi ◽  
S Panneerselvam ◽  
Ga Dheebakaran
Keyword(s):  
Tamil Nadu ◽  
Rank Order ◽  
Rainfall Variability ◽  
Climatic Zone ◽  
Annual Rainfall ◽  
Time Variability ◽  
Rainfall Analysis ◽  
North East ◽  
South West Monsoon

An analytical examination was done to work out the unevenness in point location and time to time variability in rainfall at Coimbatore and Erode district of Western agro climatic zone of Tamil Nadu (India) for 100 years (1916-2015). Simple descriptive statistics along with Co-efficient of Variation (CV) were worked to understand the rainfall variability. The long term mean seasonal and annual rainfall analysis showed that South West Monsoon (SWM) rainfall observed was (176.9 mm) & (257.9 mm) and North East Monsoon (NEM) of (336.9 mm) & (323.3 mm) and annual rainfall of (674.8 mm) & (764.4 mm) at Coimbatore and Erode respectively. The CV for seasonal and annual rainfall showed high dependability status by recording appropriate threshold level of CV for seasonal and annual rainfall. The time series rainfall data for 100 years were divided into ten year period and the correlation was carried out for the SWM and NEM using Spearman’s rank-order correlation. The results indicated the correlation between two monsoons for Coimbatore (0.14) and for erode (0.07) which indicates that there was less relation between SWM and NEM. Major emphasis was given to analyse annual and seasonal (SWM and NEM) rainfall time sequence over an extensive time gap to identify probable trend and to measure their implication. For Coimbatore and Erode districts, in both the monsoon seasons and annual analysis revealed an increasing trend for long term (100 years-1916-2015) period.

scholarly journals On some aspects of southwest monsoon rainfall over Tamilnadu

MAUSAM ◽  
2022 ◽  
Vol 46 (4) ◽  
pp. 377-382
Author(s):  
S. K. SUBRAMANIAN ◽  
V. N. THANKAPPAN
Keyword(s):  
Monsoon Rainfall ◽  
Monsoon Season ◽  
Southwest Monsoon ◽  
Point Of View ◽  
Annual Rainfall ◽  
Northeast Monsoon ◽  
The North ◽  
Rainfall Occurrence ◽  
Southwest Monsoon Rainfall ◽  
Southwest Monsoon Season

The rainfall during southwest monsoon season over Tamilnadu is quite significant from the point of view of water storage in major reservoirs as northeast monsoon rainfall, which is about half of the annual rainfall, is not stable enough due to its large interannual variability. The southwest monsoon rainfall, on the other hand, is more stable. The north-south oriented trough over Tamilnadu and adjoining Bay togetherwith upper air cyclonic circulation/trough in lower tropospheric levels account for three fourths of significant rainfall occurrence during southwest monsoon season. Rainfall during southwest monsoon and northeast monsoon seasons was found to be independent with a small negative correlation of -0.18. This shows that the southwest monsoon rainfall may not be of much use to predict the pattern of northeast monoon rainfall over Tamilnadu.  

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