INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 Rainfall Trends and Pattern of Kongu Upland, Tamil Nadu, India using GIS Techniques Ishappa Muniyappa Rathod,. Aruchamy.S Department of Geography, School of Geosciences, Bharathidasan University, Tiruchirappalli­24 [email protected] ABSTRACT The rainfall is the one of the fundamental physical parameter among the climate as for the development of society is concern and it determines the drought as well as the environmental factors for the particular region. The present study deals with the rainfall characteristics of the Kongu Upland, which includes the spatial distribution and variability through different seasons, and precipitation ratio. The study is based on 49 years of the monthly rainfall data for 40 rain gauge stations. While analyzing the long term average of monthly and annual rainfall, the annual rainfall of the region is 975.64 mm, of which the winter, summer, southwest and northeast monsoon records 24.16, 160.55, 401.19 and 389.73 mm respectively. The station Upper Niradam receives the highest rainfall of 4655.5 mm whereas Krishnapuram records the lowest of 414.4 mm. The annual variability ranges from 19.69 percent to 56.59 percent. The west, North West, North East and southern part of the region experience the heavy rainfall, whereas the east and central part of the region experiences the lowest rainfall. Key Words: Annual and seasonal rainfall, rainfall variability, precipitation ratio. 1. INTRODUCTION The rainfall is a variable which changes both in space and time (A.Akabar 2006). The relation between rainfall and space and time are varies that determines the environment and development of the particular region. Rainfall is the crucial agro­climatic parameter to the agricultural activities, and one of the designs for ground water recharge for potential ground water. The rainfall processes is known to exhibits a high degree of variability both in space and time (L.G.Lanza, 2001). Rainfall is key factor determining the sustainability and conservation of living species on the earth. In dry farming areas, where rainfall is the sources of water for crops, changes in both quantity and distribution of rainfall during the year could affect the economy an area (M.C.Ramos, 2001). Climate change is very likely to have a major impact on hydrological cycle and consequently on available of water resources, flood and drought frequencies, natural and man made eco­system, society and economy (Evans, 1996). Jagannadhasarma (2005) has analyzed the rainfall pattern of the coastal zone of Krishana­ Godavary River Basin Andhra Pradesh, India. He has made analysed the annual, monsoon and non­monsoon rainfall and spatial and frequency distribution of rainfall intensity. S.K.Tripathi (2009) has analyzed the rainfall analysis for crop planning a lesson from Uttarakhand, he has made attempted to study the weekly rainfall for the critical growing
109 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 period for the rice, sugarcane, groundnut, fodder, potato, wheat, etc crops. Anup.K.Prasad (2005). He has analyzed the extreme rainfall event of July 25­27, 2005 over Mumbai, West coast, India. 2. Aim and Objective The aim and objectives of the present paper is to review the rainfall trends and pattern of Kongu Upland for report and scrutinize for agriculture planning and cropping pattern for sustainable development. 3. Study Area The Kongu Upland is situated in North Western part of the Tamil Nadu, the region covering an area of 6806.10 sq.km falls between 10°16’ north to 11° 27' North latitude and 76° 40' East to 77° 45' East longitude. Administratively the region consists of 5 districts and comprises 20 taluks (Fig.1). The upland comprises two district head quarter is located in the north central part of the region which is Coimbatore and Tiruppur located in the north eastern part of the region. The temperature ranges between 18.32°C in the month of January and 36.42°C in the month of April. The area is bonded by Western Ghates on West, Nilagiri hills in North West and Anaimalai and Palani hill in south. The upland gradient of slope gradually decreases towards west to east, the upland region drain Bhavani, Noyal, Pallar and Amaravathi rivers. Figure1 Image showing the study area
110 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 4. Methodology The base map of Kongu Upland has been prepared from Survey of India Toposheet on 1:250000 scale. Monthly rainfall data for the period of 49 years from 1959 to 2008 has been collected from Indian Meteorological Department Pune, and Economics and Statistical Department Chennai. There are 40 in and around rainfall station have been taken into consideration for analyzing long term mean monthly, seasonal and annual rainfall pattern has been calculated. The co­efficient of variability where worked out. There are some rain gauge stations have been established during 1980 and 1996. The collected data has been processed and analyzed by preparing various charts maps and diagrams using GIS software. 5. Result and Discussion 5.1. Variation of Monthly Rainfall The variation of rainfall of the Kongu upland inferred that the variation of rainfall is takes every month and the intensity of rainfall gradually increasing from the January to July, and suddenly decreasing trend shows in from July to September. The highly intensity of rainfall trends depicts in the month of October and November and these months get maximum peak of rainfall and it reaches its maximum in the month of October and decreasing trends shows from month of December and lowest of rainfall in the month of January.(Fig.2). However Upper Niradam records 1202.01mm in the month of July, 996.25mm in June, and 924.22 mm in August and it experience lowest rainfall in the month of February which is 14.12mm. The lowest rainfall recorded at Coimbatore town which is 4.1 mm in the month of February and its maximum rainfall is 135mm in the month of October. The southern part of region such as Upper niradam, Anaimalai, Kodaikanal, Aliyar nagar, Attakatti, Valaparai, and Nallar conony experiences heavy rainfall in the months of June, July and September. The north western part Anaikatti and Coonoor experiences good rainfall during these months. However the linear trend shows the good increasing result in the every month Longterm mean monthly rainfall 200 y = 10.84x + 10.841 R 2 = 0.5663 180 Rainfall ( MM ) 160 140 120 100 80 60 40 Series1 20 Linear (Series1)
0 1 2 3 4 5 6 7 Months 8 9 10 11 12 Figure 2: Monthly rainfall data of study area 111 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 5.2. Mean Annual Rainfall The long term mean annual rainfall of the region is 975.64mm. The region is characterized with unique aerial topography because of Western Ghat. The western part of the region is bounded with the Nilagiri hills and Palaghat gap and the south part of the region is bounded with the Anaimalai and Palani hills. The most of the foot hills of the region will get the maximum rainfall during all season. The most of the foot hill regions are in the wind ward for the upland region such as Upper niradam, Valparai, Attakatti, Anaikatti, Anaimalai, Aliyar nagar and Mettupalayam, the most of the foot hill of the regions will get more than 850 mm rainfall. However the eastern Sulthanpet, Palladam, Krishnapuram are located at lee ward of upland region naturally get very less rain which is less than 400 mm and some central part the region will get good amount of rainfall. The central part and eastern part of the upland will experiences the uniformity in rainfall but the most of the southern part of region which are experiences maximum rainfall and these places are called wettest part of region (Fig.3) such as Valaparai and Upper niradam. 5.3. Rainfall Zones 1. High rainfall zone: (above 850 mm): In the southern part Upper Niradam, Anaimalai, Valaparai, Attakatti, Avanashi, Coonoor, Kodaikanal, Kothagiri. 2. Modarate rainfall zone (700­850mm) Pollachi, P.N.Palayam, Aliyar nagar,Negamam. 3. Normal rainfall zone :( 500­699mm):Amaravati nagar, Mettupalyam, Tirumoorthy nagar, Nallar colony, Virupakshi. 4. Low rainfall zones: (400­499mm):Bhavani sagar, Kangyem, Palani, Vettaikarnpudur, Podanur, Chitrachavadi, and Pongalur, and Udumalaipettai 5. Very low rainfall zones :( Below 400 mm): Annur, Pedamapatti, Coimbatore town, Palladam, Peelamedu, Krrishanpuram, Poolankinar, Sultanpet and Sulur. Figure 3 Rainfall zones in study area
112 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 5.4. Winter Season Rainfall The winter season average rainfall is 24 mm and it contributes 2.47% of annual rainfall. This season heavily experiences low rainfall and it is driest among the all season in the upland region as well in the Tamil Nadu. The upland will experiences the high pressure area during this season due to the low temperature and the availability of moisture will be very less. The maximum rainfall recorded at adjacent area of the region at Coonoor 163.3 mm and lowest recorded at Kangayem which is 5.8mm rainfall. The amount of rainfall decreases in the north east that is less than 10 mm rainfall and in the south the average 30 mm rainfall but in the north western part such as Mettupalyam, Attakatti and adjacent area of upland which is Coonoor will receives maximum rainfall during this season. The remaining area of the upland receives uniformity of the rainfall and some eastern pockets of region will get least rainfall, (Fig.4) because the eastern region are very for from the western ghat so the moisture air will not reach up to eastern extent. 5.5. Summer Season Rainfall Summer is hottest weather season the mount of rainfall gradually increases and however the amount of rainfall occurrence in this season is largely due to convection effect. The maximum rainfall 370.7mm at Upper niradam and minimum 69.8 mm at Krinshnapur, during this season the area will experiences the low pressure due to high temperature and most of rain will occurs with convection effect. The characteristic of this season is high humidity and almost area deficits in the shortage of drinking water. The Upper niradam,Valparai and Coonoor located at western ghat and it is tip of wind ward it will get maximum rain, however the leeward places of the region are experiences low rainfall. The 95% of area under the leeward (Fig.4) these area will get low rainfall, such as Krishnapuram, Kumarlingam, Chitraichavadi, Coimbatore. 5.6. South West Monsoon Season Rainfall The amount of rainfall during this season comparatively to winter and summer this season experience good rainfall but huge amount rainfall variation can found during this season. The upland and as well as Tamil Nadu will get good rain during the north east monsoon season even though the influences of south west monsoon season of India the upland region will get good rain. This is the unique characteristics of upland region, because the Palaghat gap and western ghat will brings the monsoon wind to the upland region. The average rainfall of the upland is 401.19mm and its contributes the 41.12% of annual rainfall, even though this season will contribute good amount of rainfall but not in the uniformity, only some places will get good amount of rainfall. However the south west monsoon gives huge amount of rainfall variation comparatively to the other season, (Fig.4) the 20% of area will experiences the heaviest rainfall during the season and rest of the area will get least amount of rainfall such as the central part, eastern part and south and south eastern part of region will gives less rain and it is in uniformity in the amount of rainfall, the eastern, central part, and Palghat gap will get less than 150 mm rainfall and north western part, north eastern part and south western part will get more than 300 mm rainfall.
113 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 5.7. North East Monsoon Season Rainfall The north east monsoon is major rainy season in Tamil Nadu as well in the region of Kongu Upland. The north east monsoon gives maximum rainfall for the enter region, because in other season the upland region will get heaviest rainfall but this season will gives maximum rain for enter region. This season will get enter rain from retreat monsoon that is from October to December and in this season the agricultural activities takes places due heavy rain during this season, farmer are likely ready to start their showing activities to their field. This season average rainfall 389.73 mm and it contributes 39.94% of annual rainfall,(Fig.4) comparatively to the south west monsoon rainfall this season will get less rainfall, however the entire region will uniformity in rainfall during this season. The most of north east monsoon region it gives good rain for the upland due to the low pressure area will create during this period, the minimum rainfall of this season is 250 mm and this result shows good rainfall during this season. The eastern part of the region some pockets such as Krishnapuram, Sultanpetai, Annur, Kallipalayam, and Avanashi rest of area will get uniformity and north western and southern part of the region get heaviest rainfall during this season, the Coonoor, Kodaikanal and Upper niradam these places are wettest places of the region. Figure 4 Monsoon season details
114 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 Table.1 Rainfall data in various regions in study area S.No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Station Aliyar nagar Amaravati nagar Anaikatti Anamalai Annur Attakatti Avanashi Bhavanisagar Chatrapatti Chitraichavadi Coimbatore town Coonoor Dharapuram Kallipalayam Kangayem Kodaikanal Kothagiri Krishnapuram Kumarlingam Mettupalayam Nallar colony Negamam P.N.Palayam Palani Palladam Pedamapatti Peelamedu Podanur Pollachi Pongalur Poolankinar Sultanpetai Sulur Sundakapalayam Thirumurthinagar Tiruppur Udumalaipet Upper niradam Valparai Virupakshi Total winter 2.38 3.05 3.56 0.83 2.25 2.48 0.91 3.44 2.67 2.32 1.71 9.88 2.88 2.15 0.95 4.57 3.64 3.06 3.34 5.77 2.96 1.65 2.94 3.00 1.54 2.67 2.35 2.79 1.51 2.61 3.26 1.54 2.04 1.72 3.15 1.88 2.62 0.63 0.98 2.75 2.47 summer 18.92 14.33 22.95 9.13 20.73 18.22 14.15 22.27 16.06 14.86 17.55 20.93 21.06 23.56 19.35 20.11 21.97 16.84 17.03 21.88 16.58 19.53 20.91 16.01 20.44 20.85 20.30 17.99 15.92 21.09 18.64 25.56 24.10 19.28 16.77 21.49 18.43 7.96 11.58 15.78 16.45 swm 34.95 18.89 22.59 76.71 30 32.01 53.94 24.88 26.42 35.93 27.10 21.20 18.43 16.96 29.33 33.60 26.60 14.59 15.73 19.87 26.29 40.99 24.54 20.63 20.33 21.46 24.80 24.18 44.35 22.40 17.99 23.62 19.72 30.97 21.75 26.56 19.77 78.52 72.78 28.59 41.12 nem 43.74 63.73 50.89 13.31 46.61 47.22 30.98 49.39 54.81 46.88 53.60 47.97 57.61 57.32 50.35 41.70 47.78 65.49 63.90 52.46 54.15 37.81 51.59 60.35 57.68 55.00 52.54 55.01 38.19 53.88 60.09 49.26 54.14 48.01 58.32 50.05 59.15 12.87 14.65 52.86 39.94
115 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 5.8. Variability of Rainfall “Variability defined as the deviation from mean” or “ratio of the standard deviation to the mean rainfall” and in other words variability of co­efficient of variation. 5.9. Annual Variability of Rainfall The annual rainfall variability of Kongu Upland is stretches between 19.69 % to above the normal which is 224.5 % (Table.2). The maximum variability of rainfall recorded at Avanashi which is 224.5% and lowest rainfall variability19.69% recorded at adjacent area of upland which is Coonoor (Fig.5).The maximum variability concentrating in north western part of upland and south central part of upland that is Chaitrachavadi and Podanur, where as the southern part and central part of upland is experiences the low variability of rainfall. The variability of rainfall distributed uniformly over the upland except north western part of upland which is Avanashi, the result shows that the rainfall deviating from the normal. Figure 5: Rainfall variability 5.9.1. Winter Season Rainfall Variability The rainfall variability during this season is highly fluctuating because the low rainfall. The minimum rainfall variability recorded at Coonoor 77.29% which is the adjacent area of upland, and maximum rainfall variability recorded at Kangyem which is 248.02 % (Table.2). However the result shows the uniformity in the variability of rainfall and over the upland but
116 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 the north western part shows good rainfall variability (Fig.6), the east, and south east and north eastern shows the maximum rainfall variability. The variability of rainfall variation is very high during this season only the Mettupalaya taluk only show good rainfall variability in winter season. 5.9.2. Summer Season Variability of Rainfall The rainfall variability of hot summer is well distributed and it is very less than winter season. The maximum rainfall variability is recorded at 80.25% and (Table.2) minimum recorded at Kangayem 48.64% (Fig.6), the eastern part such as Avanashi, Sultanpet, Palladam, Kallipalayam, and Annur are resulting the good rainfall variability due to the moisture availability during summer free monsoon the mostly rainfall occurred through convection effect , most of the hot areas will get good rainfall. The western part such as Anaikatti and in the south Palaghat gap, Pollachi and south of Tiruppur are maximum rainfall variability areas and rest of the areas will get uniformity in the variability and north of upland resulting good rainfall variability. 5.9.3. South West Monsoon Variability of Rainfall This season will have some variations in rainfall variability due to the influences of south west monsoon rainfall of India. In west and the west of south and north, most of western ghat influences the good rainfall variability and some pocket such as Sundakapalayam and Palladam resulting the good rainfall variability (Fig.6). The north western, north eastern, southern part of upland and central part of upland resulting the maximum rainfall variability, the maximum rainfall variability recorded at Avanashi 415.43% (Table.2) and minimum rainfall variability recorded at the Valparai, Pollachi, and Anaimalai. The variability of rainfall of the upland during this season is good comparatively to the winter and summer season because of the rainfall during this season this season receives well from the south west monsoon rainfall of India and most of north eastern part of upland will have some maximum variability of rainfall. 5.9.4. North East Monsoon Variability Of Rainfall The variability of rainfall in this season result shows the uniformly well distributed. The variability of rainfall is very less than the other season even though the north western part of the upland and Anaikatti are the experiences the higher the variability and in the eastern side the Pongalur experiences the higher the rainfall variability due to the withdrawal of south west monsoon. The south west monsoon will gives good rainfall for foot hill of upland areas. The north eastern rainfall will not reach to that extant so the availability of moisture in very less it won’t be reach up to the foot hills of western ghat areas, due to the areas rainfall normally deviating from the mean. The rest of the area will have uniformity in variability of rainfall (Fig.6). The maximum variability recorded at Podanur which is 68.02 and minimum recorded at Coonoor which is 34.08 % (Table.2). The north east monsoon season giving the good result than the other seasons.
117 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 Figure 6: Monsoon based variability 5.9.5. Precipitation Ratio Px ­ Pn x 100. Px =Maximum rainfall minus Minimum rainfall =Pn x 100 Where Px and Pn, represent the maximum and minimum of rainfall over the series of year and Pm is the mean annual rainfall. The abnormalities of rainfall at any location may be brought by a simple ratio of precipitation. It is the difference between maximum and minimum rainfall of over the series of expressed in terms of mean. This ratio may give the stability of rainfall with special relationship. Higher the ratio, higher in abnormality in rainfall and vice versa. The maximum abnormality recorded at Avanshi 1617.01% and minimum abnormality recorded at adjacent area of region which is Coonoor 53.66% (Fg.7), the rainfall ratio distributed well uniformly except in the north eastern region of region results the very high in the abnormality in the rainfall. The rest of the region uniformly distributed well in over the region.
118 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article S.No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 ISSN 0976 – 4402 Table 2: Variation of rainfall in study area ­ 2 Station winter summer swm nem annual Aliyar nagar 149.95 63.71 41.91 51.13 27.6 Amaravati nagar 203.91 66.18 59.73 42.63 30.22 Anaikatti 115.34 65.19 74.07 46.51 29.23 Anamalai 130 62.82 31.99 43.56 26.13 Annur 174.36 65.08 58.25 76.63 48.47 Attakatti 143.5 79.93 68.69 47.24 32.33 Avanashi 204.74 54.08 415.43 42.75 224.5 Bhavanisagar 128.54 62.93 71.96 43.5 27.65 Chatrapatti 187.3 60.93 56.6 34.54 27.04 Chitraichavadi 190.65 63.78 42.69 52.87 32.63 Coimbatore town 209.68 67.35 49.06 53.61 33.69 Coonoor 77.29 48.88 38.71 34.08 19.69 Dharapuram 200.37 55.29 63.87 38.89 37.57 Kallipalayam 204.85 61.92 76.94 51.74 35.95 Kangayem 248.02 48.64 47.28 38.6 29.72 Kodaikanal 192.74 74.5 57.75 60.96 56.59 Kothagiri 120.94 74.77 34.99 35.89 28.03 Krishnapuram 231.65 76.07 73.71 52.77 42.2 Kumarlingam 226.58 70.86 75.24 50.51 39.69 Mettupalayam 139.06 56.6 62.99 46.77 31.63 Nallar colony 201.89 64.01 60.05 55.68 42.52 Negamam 227.51 78.34 42.11 54.25 31.81 P.N.Palayam 187.17 86.36 73.94 60.14 51.81 Palani 208.42 67.38 52.03 37.44 27.84 Palladam 232.2 80.25 67.52 42.2 31.51 Pedamapatti 182.94 63.53 67.45 50.32 32.25 Peelamedu 183.14 56.6 65.01 50.49 33.99 Podanur 201.11 63.36 82.72 68.02 52.28 Pollachi 181.42 58.06 31.62 54.9 29.26 Pongalur 198.91 49.72 82.47 57.92 37.62 Poolankinar 214.77 71.73 89.99 44.1 35.02 Sultanpetai 165.95 52.03 69.86 41.35 28.24 Sulur 180.5 77.86 75.98 57.01 42.71 Sundakapalayam 203.93 57.06 51.68 53.03 35.87 Thirumurthinagar 190.55 57.77 43.59 44.8 24.97 Tiruppur 216.27 66.61 50.32 52.18 32.96 Udumalaipet 211.17 58.76 67.6 51.56 35.91 Upper niradam 130.42 72.86 41.33 56.66 39.69 Valparai 128.05 62.3 31.022 46.51 26.87 Virupakshi 232.97 49.3 65.65 39.84 35.78
119 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 Figure 7: Annual precipitation ratio 6. Conclusion The prime focus of the study was to study the rainfall trends, variations and critical variability of the rainfall for the Kongu Upland. The study used the GIS technique to assess the rainfall trends and its variability, the study proven to the North West and North East monsoon are paramount dominant but the North west monsoon will be the stabilized to be in foot hills are permanent dominating every monsoon season, however the north east monsoon paramount dominant to the eastern region of the upland region. The windward of the western gahat region highly intensity in rainfall during monsoon season such as the Valparai, Upper Niradam, Aliyar nagar, Attakatti, and Nallar colony these places are very highly intensity in rainfall during North West monsoon season and Upper niradam may be treated as the wettest point in the region and it is located in the tip of the Anaimalai hill of western ghat and the Palaghat gap and eastern region experiences the highly deficits in the rainfall intensity. The north east monsoon will gives complete stabilized rainfall for the entire region which helps to take place for the agricultural activities in the region.
120 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 7. References 1. Gadagil.A, 1986. Annual and weekly analysis of rainfall and temperature for Pune: A multiple time series approach. Inst.Indain Geographers.Vol.8.No.1.1986 2. Anup K.Prasad, 2005.Extreme rainfall event of July 25­27, 2005 over Mumbai,West coast of India. Journal of the Indian Society of Remote Sensing, Vol.33, No.3, 2005. 3. A.R.Subramaniam.1992.Climatic variability in India. Annals, Nagi.Vol.XII.No.1&2. India. Vol.XX.No 3 pp.50­59. 1992. 4. A.K.Kulkarni.1994. A study of heavy rainfall 22­23 August, 1990 over Vidarbha region of Maharashtra.Trans.Inst.Indian Geographers.Vol.16.No.11994. 5. C.M.Philandras, 1999.Climatic variability and urbanization in Athens. Theoretical and applied climatology.63, 65­72. 6. Evans.1997.The effects of changes in the World Hydrological cycle on availability of water resource. In Bazzoz.F,Sombroek w(eds)Global climate changes and agriculture production. Chischester :John wiley and sons.pp­48 7. G.Vennila .2007. Rainfall variation analysis of vattamalaikarai sub basin, Tamil Nadu. Journal of applied hydrology.Vol.XX.No.3. pp.50­59 8. Hassan S.M. 2009.Recent rainfall trends in the FCT, Abuja. Trans.Inst.Indain Geographers.Vol.31.No.1.2009 9. H.J.Syiemlieh.2004.Orographic effects on the distribution of rainfall in north­east India. Trans.Inst.Indain Geographers.Vol.26.No.1.2009 10. M.Ahmed.2004.Impact of deforestation on pattern of rainfall and number of rainy days of 11. M.C.Ramos.2001.Rainfall distribution pattern and their over time in a Mediterranean area. Theoretical and Applied Climatology.69.163­170 12. Goapara district, Assam,India.Trans.Inst.Indain Geographers.Vol.26.No.1.2004 13. R.Ananthakrishnan.1979.Some feature of the southwest monsoon rainfall along the west coast of India.Proc.Indian Acad.Sci., Vol.88 A, Part II .pp.177­199. 14. S.K.Tripathi, 2009. Rainfall analysis for crop planning:a lesson from Utterkand. Journal of applied hydrology.Vol. XXII.No.1. 2009. 15. T.Penchalaih.1992. the spatial analysis of rainfall in the drought prone area of Cuddapah district, Andhra Pradesh. Trans.Inst.Indain Geographers.Vol.14.No.1.1992.
121 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 2 ,2010 © Copyright 2010 All rights reserved Integrated Publishing services Review Article ISSN 0976 – 4402 16. V.V.Jagannadha Sarma, 2005.Rainfall pattern in the coastal zone of Krishna Godavary basin Andhra Pradesh India. Journal of applied hydrology.Vol.XVIII.No.1&2 pp­ 1­11. 17. P. Alaguraja and M.Manivel, S.R.Nagarathinam, R.Sathivel, and D.Yuvaraj Rainfall Distribution Study in Coimbatore District Tamil Nadu Using GIS. “Recent Trends in Water Research, I.K International Publication. New Delhi vol­1, pp­ 92­115
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