Journal of Information and Computational Science ISSN: 1548-7741

Rainfall Characteristics, Distribution of Temperature and Wind Velocity of Chittoor Municipal Corporation,

P. Muralidhar* & Dr.M. Reddi Bhaskara Reddy#

Research Scholar*, Assistant Professor# Department of Geography, S.V. University, , Andhra Pradesh – 517 502 Correspondent Email: [email protected]

Abstract

The aim of the present study is rainfall characteristics distribution of Temperature and wind velocity data of Chittoor Municipal Corporation, Chittoor district and contains the rain gauge station with annual normal rain fall 895.65mm. The study area receives rainfall from winter (25.08 mm.), summer (97.70 mm.) southwest monsoon (424.64 mm.) and the northeast monsoon (348.13 mm.). From the analysis of seasonal rainfall it is found that the study region receives high rainfall in both southwest and northeast monsoon periods. In the eastern and southern plains of the mandal the rainfall recorded is high in northeast monsoon period. The relative humidity is about 70 and 80 percent in the mornings and about 60 to 65 per cent in the afternoon during the period from July to December. It decreases thereafter. The period from February to May is the driest part of the year when the relative humidity in the afternoons are between 25 and 40 per cent.

Key Words: Rainfall, Temperature, Humidity and Wind velocity.

Introduction

Climate is an important element of the physical environment of mankind. It is the aggregate of atmospheric conditions involving heat, moisture and air movement. In a developing country like climatic characteristics have a dominant role in affecting the economic pattern, way of life, mode of living, food preferences, costumes and even the behavioural responses of the people. In India despite a lot of scientific and technological developments our dependence on monsoon rainfall for carrying out successful agricultural activities, has not been minimized. The climate of India belongs to the ‘tropical monsoon type’ indicating the impact of its location in tropical belt and the monsoon winds. Although a sizeable part of the country lying north of the Tropic of Cancer falls in the northern temperate zone but the shutting effects of the Himalayas

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and the existence of the Indian Ocean in the south have played significant role in giving India a distinctive climatic characteristics.

Spatial location, site, situation and their importance

Chittoor town, one of the ancient towns of Andhra Pradesh state, is also the second largest town in Chittoor District, next to Tirupati town (according to 2011 census, it ranks 13th position in Andhra Pradesh state and 5th position in region). It is situated at a height of 394.5mts above MSL, covering an area of 33.54 sq.km with the population of 3,20,567 (2011 census). It, of course, happened that the urban character both in respect of size and function was emerged by the growth and accretion about a pre-urban nucleus at the tri-state junction of Bangalore-Chennai Highway (NH-4) and a railway station on the – Katpadi line of Southern Railway. The town is located 13° 9' to 13° 16' N & 79° 3' to 79° 8' E and occupies a position in the southern most part of Andhra Pradesh state at a distance of 150 km. from Chennai (the capital city of Tamil Nadu state) and 180 km. from Bangalore (the capital city of Karnataka state)Metropolitan Cities. It is served both by Railways and Roadways. It is connected with Karnataka and Tamil Nadu with a good network of roadways. The Chennai-Mumbai trunk road and the Chennai-Bangalore National Highway pass through this town.

The city has grown on the banks of the river Ponnai in almost star-shaped pattern in the midst of beautiful hills and hillocks all around eastern parts (The Eastern Ghat ranges entered the district as Seshachalam hills and the world’s famous Sri Temple is situated on these hills in Tirupati- with a name ‘Edukondalu’ means ‘Seven Hills’). Some element of this wider setting got altered in course of time and others, while remaining permanent features of the scene, change in their significance for life and development of the town.

Therefore, the analysis of the setting of the city of Chittoor, and its importance reveals innumerable variants and individual peculiarities in respect of the conditions that have determined the location. Thus, the city has developed as a commercial as well as religious centre. Tracts of flat-land adequate for the layout of factories and for indispensable buildings have also exercised importance. But, in some directions, natural depressions and slight ruggedness due to rocky outcrops limit the extension of the urban growth.

Study Area

Chitoor town has been selected for the purpose of investigation and an attempt has been made to study the impact of urbangrowth on environment. Chittoor town has been growing at a faster rate and the Chittoor urban system is the second largest urban agglomeration in Rayalaseema region only next to Tirupati. Particularly during the last five decades the Chittoor town has been experienced an aerial expansion in terms of residential, commercial and industrial areas. The intra-urban transport network, public and semipublic functional zones within the city

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and changes in the number of parks and playgrounds and also the formation of slums all together have been led to many environmental problems. The researchers has made an attempt to trace out the factors responsible for the urban growth and its impact on urban environment and also analyzed the changing scenario of city environment along with possible remedial measures.

Though the study area, Chittoor District, is bordered by the ‘humid zone’ of Nellore district and Tamil Nadu State in the east and north-east, and the ‘arid zone’ of Anantapur on the west; it become a rain shadow area and experiences the ‘semiarid’ climatic conditions. Rainfall is low and erratic. Topography is mostly hilly and undulating. Soils are rarely fertile. Drainage is non-perennial. Groundwater supplies are quite limited and available only in a few months of a year. Due to these factors dry cultivation is practiced in most parts of the district. Droughts are next door to the farmers, and determine the density of crops in any given year. To overcome the drawbacks of climate, the surface run-off is stored in a number of system tanks during the rainy season. Surface water irrigation is traditional practice for centuries in this area. Thousands of wells have been dug throughout the district, either to supplement the tank irrigation or as an independent source of water supply.

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Objectives

The present paper has attempted to make an assessment of rainfall characteristics of Chittoor Municipal Corporation of Chittoor district of Andhra Pradesh. This study has been under taken with, rainfall characterstics, distribution of temperature and wind velocity of the area. The objectives of the present study are: 1. To identify the seasonal pattern of Rainfall in the study area, 2. To identify the distribution of Temperature and 3. To identify the wind velocity of the study area.

Methodology

The present study is based on the rainfall data collected from chief planning officer, Chittoor and Assistant statistical officer, Chittoor Municipal Corporation for 10 years. The data has been grouped in seasonally from 2010to 2019. The seasonally rainfall data over a period of 10 years was collected from rain gauge stations in and around Chittoor Municipal Corporation. The data was used to analyses seasonal and annual rainfall variation and frequency of occurrence of rainfall.

Rainfall

The geographical conditions of India play a crucial role in influencing the climate because they determine the direction of monsoon winds and their intensity. Rainfall in India is mainly dependent in different degrees on the southwest and northeast monsoons. In view of the importance of monsoons as the main source of rainfall in India, several studies have been carried out and many explanations regarding the origin and maintenance of southwest monsoon have been offered (Flohn 1960). Yet the underlying mechanism of the southwest monsoon system is extremely complex and not fully understood. The seasonal conditions during the southwest and northeast monsoons vary in different degrees. There may be some short-term and long-term fluctuations in the onset, advance, retreat and intensity of their activity depending upon the height above mean sea level (MSL), distance from the sea, general configuration of the topography, moisture capability, physical barriers and its latitudinal expansion. Due to these reasons the characteristics of rainfall vary both spatially and temporally with major effect on crop farming and cause enormous hardship to the people. Due to the diversity of relief in the district/town and climatic conditions particularly the rainfall differs seasonally and regionally to a great extent. As said earlier the location of Chittoor Town in the southeastern fringe of Andhra Pradesh, its varied surface configuration, its somewhat nearness to Bay of Bengal Coast, the direction of prevailing winds, all combine to generate climatic environment with wide variety of characteristics. To study the characteristics of rainfall in the study area the criteria suggested and

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adopted by the India Meteorological Department (I.M.D), Pune, have been used in the present investigation in the following way:

(a) The cold weather season or winter season ( January to February) (b) The hot weather season or summer season (March to May) (c) The southwest monsoon season (June to September) (d) The northeast monsoon season (October to December) The two seasons namely the southwest monsoon and the northeast monsoons are very effective in the study area when compared with the other two.

Southwest Monsoon Season (June to September)

The study area comes under the influence of southwest monsoon and this season lasts over the study area from June till the end of September. The rainfall is discontinuous and is characterized by alterations of moderate to light rain with intervening dry spells. It is this variation of the monsoon which is of great agricultural significance for kharif crops in the study area. Rainfall of 424.64mm., which forms 47.41 per cent of the total normal annual rainfall of 895.65mm., in the study area is received during the southwest monsoon season, with normal number of rainy days of 24.74 days. This reveals that the rainfall in the southwest monsoon is comparatively higher than the rainfall of northeast monsoon. It is quite interesting to note that during this season the intensity of rainfall is 17.16mm per a rainy day. The variability is 37.26 per cent and rainfall ratio is 163.2.

Northeast Monsoon Season (October to December)

By the middle of October, the belt of low pressure is transferred to Bay of Bengal. Under its influence the retreating southwest monsoon current curves round as it is deflected towards the Peninsula from the northeast. The retreating monsoon winds cause occasional showers. However, during October to December cyclonic storms form in the Bay of Bengal and when they strike the Coromandel Coast they bring heavy rains. Rainfall of about 348.23mm., amounting to 38.88 per cent of normal annual rainfall in the study area is received during the northeast monsoon season with normal number of rainy days of 18.07 days. The intensity of rainfall is 19.27mm per a rainy day, and the variability is 49.92 per cent. The rainfall ratio is 229.05, and it is a healthy sign too when compared with the State’s northeast monsoon figure, i.e., 201.1mm. In this season the Chittoor Town receives the highest rainfall in the month of October under the influence of northeast monsoon which forms 18.84 per cent of the normal annual rainfall followed by November and September.

Hot Weather Rainfall or Summer Rainfall (March to May)

In the early part of the hot weather season, weather disturbances continue to enter the country. These incursions bring rain to some parts of the country. As the season advances the thunder storms become more and more frequent and thus increases the rainfall. So during the

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month of May alone the study area receives a rainfall amounting to 7.79 per cent of the normal annual rainfall as against 14.68 per cent which occurs between January to May.

Winter Season (January and February)

The study area receives some rainfall in winter season also and it amounts to 25.08mm., with rainy days of 1.61. So, into, the particulars of rainfall occurred in Chittoor town are tabulated in table No. 1 Table No - 1 Particulars of Rainfall in Chittoor Municipal Corporation

S.No Name of Normal Average No. Rainfall Rainfall Rainfall the season Rainfall(mm) of rainy days Intensity Variability (%) Ratio (%)

1 Winter 25.08 1.61 15.57 163.56 832.5 Season

2 Summer 97.70 5.66 17.21 83.49 483.8 Season

3 S.W.M 424.64 24.74 17.16 37.26 163.2 Season

4 N.E.M 348.23 18.07 19.27 49.92 229.05 Season

5 Annual 895.65 50.08 17.88 32.29 189.5 Rainfall

Source: Computed from collected data

From the above table, it is known that southwest monsoon season is the principle monsoon season of the study area with rainfall of 424.64mm., when compared to the normal rainfall of northeast monsoon; i.e., 348.23mm. The number of rainy days are also more (24.74) in southwest monsoon season than in northeast monsoon (18.07). The rainfall is more variable in northeast monsoon season (49.92) than in southwest monsoon season (37.26). The rainfall ratio or the abnormality is also more in northeast monsoon season than in southwest monsoon season. Overall the rainfall and climate are favourable for the agricultural operations and the development of the town.

Temperature

Though Chittoor Town is the head-quarters town of Chittoor District, the meteorological observatory maintained by India Meteorological Deportment (I.M.D) is located at Arogyavaram,

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60 km. from Chittoor Town. Another observatory is located in Tirupati, 56 km. from Chittoor Town and it is maintained by Airport Authorities. The data related to climate was collected from those two observatories and tabulated below.

As stated earlier, Chittoor Town is situated at an altitude of 394.5 mts. above MSL, it enjoys somewhat cooler climate. This moderate cooler weather is one of the reasons for the selection of Chittoor as district headquarters by the earlier rulers. The mean maximum and mean minimum temperature at Arogyavaram is 31.4o C, 19.9oC respectively are comparatively cooler than at Tirupati i.e. 33.4oC, 21.5oC. So the mean monthly maximum may be around 34.4oC and mean monthly minimum is around 21.5oC. Both April and May months are hottest months with mean maximum temperature of 34.9oC, as they continue upto the month of June till the pre- monsoonal showers in the middle of June. December is the coldest month with maximum temperature of 27oC. (Table 2)

Humidity

The data on relative humidity is also furnished in Table 2. The relative humidity is about 70 and 80 percent in the mornings and about 60 to 65 per cent in the afternoon during the period from July to December. It decreases thereafter. The period from February to May is the driest part of the year when the relative humidities in the afternoons are between 25 and 40 per cent.

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TABLE NO. 2 MEAN MONTHLY CLIMATIC DATA

Mean Monthly Temperature (°C) Mean Monthly Relative Humidity (%) Arogyavaram Tirupati Arogyavaram Tirupati Mean Mean Mean Mean 8.30 17.30 8.30 17.30 Month Mean Mean Maximum Minimum Maximum Minimum hrs. hrs hrs. hrs January 26.6 15.4 21.2 29.1 15.6 22.3 78 47 82 47 February 30 16.9 23.5 32.2 17.7 25 61 31 77 38 March 33.3 19.4 26.4 33.7 20.3 27 59 25 72 25 April 34.9 22.4 28.7 37.9 24.1 31 64 35 73 34 May 34.8 23.9 29.4 38.6 26.1 32.3 58 38 65 38 June 32.1 22.8 27.5 36.9 25.4 31.2 66 47 67 41 July 29.9 21.8 25.9 35.8 24.2 30.6 72 58 72 46 August 29.9 21.8 25.9 34.1 23.8 29.1 73 58 70 47 September 29.4 21.2 25.3 33.6 22.9 28.3 73 57 74 50 October 28.4 20.1 24.3 31.6 21.6 26.6 78 66 82 59 November 26.7 17.6 22.2 29.1 19.3 24.2 77 60 82 60 December 25.3 15.5 20.4 27.7 17.2 22.4 80 57 83 58 Yearly Mean 30.1 19.9 25 33.4 21.5 27.4 70 48 75 46

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WINDS

With regards to the winds, violent types are very rare. Hot, dry and gusty winds blow from different quarters towards chittoor town during the dry season. Otherwise even during monsoon seasons the air is calm and undisturbed. The mean wind velocity varies from a maximum of 18.7 km/hour in July month to a minimum of 8.1 km/hour in October. The mean wind velocity is 15 km/hour in June, July and August months. It varies from 10 km/hour to 16 km/hour in January, April, May and September months. The mean wind velocity is less than 10 km/hour in February, March, October, November and December months. Table No:2.6 THE MEAN MONTHLY WIND VELOCITY OF CHITTOOR MUNICIPAL CORPORATION S.No Month Mean velocity for 24 Hrs kms/hour 1. January 9.8 2. February 9.2 3. March 9.9 4. April 10.4 5. May 11.9 6. June 18.6 7. July 18.9 8. August 18.0 9. September 12.9 10. October 8.0 11. November 8.5 12. December 8.9

Conclusion

This paper is an attempt to study typical rainfall characteristics as well as probability levels in the study area. Rainfall is the most important component in agriculture production and its spatial and temporal distribution is uneven, uncertain and erratic in nature. According to the concept of water resources when the water supply due to rainfall exceeds the water need, there is surplus of water part of which goes into the soil and the rest joins the streams and rivers by way of surface and sub-surface runoff. Under favourable conditions the excess water reaches even the deeper parts of the earth’s crusts and rises the groundwater table. Thus, the groundwater potential of any region is dependent upon its accumulated water surplus.

Climate is not so favourable for the development of land, water and agricultural resources. The study area falls under the Semi-arid zone of south India due to its typically

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geographically location and diversified physical conditions. Temperature is as high as 34.9°C and the normal annual rainfall is 895.65 mm. The Municipal corporation area receives rainfall from winter (25.08 mm), summer (97.70) southwest monsoon (424.64 mm) and the northeast monsoon (348.0 mm). From the analysis of seasonal rainfall it is found that the study area receives high rainfall in both southwest and northeast monsoon periods. In the eastern and southern plains of the Municipal Corporation the rainfall recorded is high in northeast monsoon period. It is presumed that owing to the formation of low pressure in Bay of Bengal during this monsoon, the rainfall received is high in this part of the Chittoor Municipal Corporation area. The mean wind velocity is less than 10 km/hour in February, March, October, November and December months.

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