scholarly journals Climatology of dry and wet spell over Vidarbha region during monsoon months

MAUSAM ◽  
2021 ◽  
Vol 52 (2) ◽  
pp. 365-370
Author(s):  
JAYANTA SARKAR ◽  
K. SEETHARAM ◽  
S. K. SHAHA

In this investigation 10-day period-wise simple probability, 10-day period-wise  probability of consecutive dry and wet spells of different lengths, and month-wise different parameters, and properties of Markov Chain Model over Vidarbha region during south-west monsoon months have been studied.   For this purpose, daily rainfall data (1 June – 30 September) of 11 stations covering all the districts of Vidarbha for the period 1960-90 have been utilized.   The study reveals that over Vidarbha during monsoon season (June - September) probability of a day being wet and probability of consecutive wet spell of different lengths are by and large high during the last and first 10-day periods of July and August respectively when the monsoon is at its peak. During the first two 10-day periods in June and last two 10-day periods in September, the probabilities of a dry day and that of consecutive dry spell of different lengths and quite high. During July and August a maximum of 12-14 wet days are expected and wet spell, on an average, lasts for 2 days. Stationary probability of the occurrence of wet day (pi2) is found to be maximum during July making it the most humid month in the monsoon season.

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3051
Author(s):  
Girma Berhe Adane ◽  
Birtukan Abebe Hirpa ◽  
Chul-Hee Lim ◽  
Woo-Kyun Lee

This study aimed to analyze the probability of the occurrence of dry/wet spell rainfall using the Markov chain model in the Upper Awash River Basin, Ethiopia. The rainfall analysis was conducted in the short rainy (Belg) and long rainy (Kiremt) seasons on a dekadal (10–day) scale over a 30-year period. In the Belg season, continuous, three-dekad dry spells were prevalent at all stations. Persistent dry spells might result in meteorological, hydrological, and socio-economic drought (in that order) and merge with the Kiremt season. The consecutive wet dekads of the Kiremt season indicate a higher probability of wet dekads at all stations, except Metehara. This station experienced a short duration (dekads 20–23) of wet spells, in which precipitation is more than 50% likely. Nevertheless, surplus rainwater may be recorded at Debrezeit and Wonji only in the Kiremt season because of a higher probability of wet spells in most dekads (dekads 19–24). At these stations, rainfall can be harvested for better water management practices to supply irrigation during the dry season, to conserve moisture, and to reduce erosion. This reduces the vulnerability of the farmers around the river basin, particularly in areas where dry spell dekads are dominant.


Author(s):  
B. N. Thorat ◽  
B. M. Thombre ◽  
A. T. Shinde

In the present study pedigree records maintained at Cattle Cross Breeding Project, VNMKV, Parbhani (Maharashtra) for the period of 1995-2010 were utilized to study correlation of lactation length and climatic factors. The climatic parameters considered were temperature, relative humidity, wind velocity, sunshine hours and dry and wet bulb temperature along with THI. The data on monthly lactation length of cows calved during cold, hot, south-west monsoon and post monsoon seasons were considered. Correlation and multiple regression analysis was used to investigate various sources of variation in monthly lactation length. Monthly lactation length data were analyzed to ascertain the effect of climatic attributes and to know their association with lactation lengths. The average monthly lactation length was recorded as 220.21 + 6.75 days in Deoni cattle. It can be inferred that maximum lactation length was recorded during post monsoon season (240.94 + 11.26 days) followed by south-west monsoon season (222.28 + 9.00 days), cold season (218.67 + 8.25 days) and hot season (198.95 + 10.71 days), respectively..


Author(s):  
Pradeep Raja K.P. ◽  
Suresh Ramaswwamy Reddy

India as a tropical country, depends solely on south west Monsoon. Southwest monsoon spans between June and September. The present study is aimed to carry out the probable trend of rainfall and to evaluate its implications on the tanks in Hunsur taluk of Mysore district, Karnataka, India. These tanks were the livelihood sources of water for the farmers in the command area. The lakes considered under this case study have been completely dried up in the recent past. Inconsistency of rainfall is one of the factors which govern the degradation of Lakes. Trend analysis is carried on 40 years daily rainfall data (1975-2014) for monthly, seasonal and annual average values using Mann-Kendall test and Sen’s slope estimation. The analysis shows ‘no trend’ for the months of January, February, March and June. There is an ‘increasing trend’ for the months of August, October and December. However, there is a ‘decreasing trend’ for the months of April, May, July, September and November. The decadal variation indicates a very significant decrease of rainfall for the months of June and July; particularly in the recent decade (2005-2014) and hence a ‘negative trend’ in the South-West monsoon. This may be one of the reasons for the deterioration of tanks in the study area.


Author(s):  
Sumera Farooq ◽  
Nazia Arshad

Sediment characteristics plays important role in the determination and functioning of coastal ecosystems. The present study is an attempt to evaluate the variability in sediment characteristics of the three beaches: Clifton, Sandspit and Buleji, at the Karachi coast. The samples were collected during pre-monsoon and south-west monsoon seasons to evaluate the seasonal differences. The sediments of the three sites showed variations in moisture content, organic matter and grain size. The highest mean moisture (27.17%) and organic contents (3.5 %) were recorded from the sediments of Clifton. The maximum fraction of sediments (> 80 %) consist of fine to very fine sand at all studied sites. The sediments of Clifton were high in very fine sand fraction and low in coarse sand fraction as compared to Sandspit and Buleji. The sediments of all the three studied sites are moderately sorted, negatively coarse-skewed and showed leptokurtic distribution. The studied beaches of Clifton, Sandspit and Buleji shows dissimilarity in sediment characteristics as indicated through Cluster and PCA analysis. The monsoonal influence on sediment characteristics was also observed at all the three studied beaches. The strong wave action during SW monsoon season results in the deposition of the coarser sediments at the high tide level thus increasing the steepness of the beaches.


MAUSAM ◽  
2021 ◽  
Vol 62 (2) ◽  
pp. 179-196
Author(s):  
D.S. PAI ◽  
O.P. SREEJITH ◽  
S.G. NARGUND ◽  
MADHURI MUSALE ◽  
AJIT TYAGI

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).


MAUSAM ◽  
2021 ◽  
Vol 51 (1) ◽  
pp. 25-38
Author(s):  
P. G. GORE ◽  
V. THAPLIYAL

Based on the daily rainfall data of the past 90 years (1901-90), the initial and conditional probabilities of a wet week and the probabilities of 2 and 3 consecutive wet weeks have been computed for all the districts of Maharashtra during the southwest monsoon season by using Markov Chain model. A temporal and spatial distribution of probabilities of wet weeks have been studied in detail. Most of the districts show the highest probability of wet weeks during July. A few number of the districts show the second highest probability during August. The western and northeastern parts of the state show 10-16 wet weeks with high probability. The high rainfall districts along the west coast show high wet week probabilities during most of the period of the season. A few number of the districts from moderate rainfall zone, show high probability of a wet week during, July and August. A persistency in rainfall is noticed in only extreme western parts of the state. The east-west variation along 19° N shows 'L' shaped pattern for the high probability wet weeks. While, the north -south variation of the wet weeks with high probability shows a sinusoidal curve from north to south.


MAUSAM ◽  
2021 ◽  
Vol 62 (2) ◽  
pp. 253-256
Author(s):  
E. KULANDAIVELU ◽  
M. SOUNDARARAJ ◽  
M.V. GUHAN

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