DISTRIBUTION OF REFERENCE EVAPOTRANSPIRATION IN MADHYA PRADESH, INDIA

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1 DISTRIBUTION OF REFERENCE EVAPOTRANSPIRATION IN MADHYA PRADESH, INDIA *Snnd Kundu nd Deepk Khre nd Arun Mondl Deprtment of Wter Reource Development & Mngement, Indin Intitute of Technology, Roorkee, Indi *Author for Correpondence ABSTRACT Vriou meteorologicl prmeter like temperture, wind peed, rdition, humidity etc. hve coniderble impct on the wter reource. Vrition in reference evpotrnpirtion (ET 0 ) cn hve impct on the crop of the re. Thu it i extremely necery to undertnd the ET of the region before plnning nd mngement. Lndue type, oil type etc lo hve trong effect on ET of river bin. In the preent tudy FAO56 Penmn-Monteith method h been ued for etimting ET 0 for entire Mdhy Prdeh from 1971 to The reult indicte higher ET 0 during the month of My with highet being found in Indore (11.77 mm dy -1 ). The month from April to June hve coniderbly high ET 0 while other month hve low ET 0. Minimum rte of evpotrnpirtion i oberved in Jblpur during the month of December. Among the 13 ttion, Pchmrhi h the lowet ET 0 even in My (6.07 mm dy -1 ). Thu wide vrition in ET 0 ditribution i oberved in MP which i due to the effect of other climte prmeter. Key Word: Meteorologicl Prmeter, Reference Evpotrnpirtion (Et 0 ), Fo56 Penmn-Monteith Method, Mdhy Prdeh, Climte INTRODUCTION Evportion comprie n importnt prt of the therml blnce occurring on the erth urfce. It i lo prt of wter budget nd the urfce het nd wter condition re the determinnt of formtion of the urfce ecologicl environment. Thu the tudy of evportive cpcity of the lnd i lwy one of the mjor problem in hydrology nd geocience (Ping et l., 2009). The rte of reference evpotrnpirtion i generlly clculted from reference urfce where it i denoted ET 0 but dequte mount of wter i required there. Reference urfce for the purpoe i hypotheticl gr which i reference crop with pecific chrcteritic. With the help of ET 0, mny reerch hve been done like ridity/humidity condition (Wu et l., 2006), ecoytem model (Fiher et l., 2005), etimtion of rinfll-runoff nd wter ue in griculture (Allen, 2000; Hunker et l., 2002). The evpotrnpirtion of reference crop i found on the bi of the meteorologicl dt nd the clcultion i given by FAO depending on the meteorologicl prmeter nd meteorologicl dt. Thu it i difficult to pply the method in the re where there i lck of meteorologicl obervtion dt, nd recommended the ue of evporting pn obervtion dt for determining the reference crop evpotrnpirtion by FAO (Allen et l., 1998). Vriou method for empiricl etimtion of ET 0 require proper nd ccurte meurement of different prmeter like temperture, humidity, wind peed, unhine, olr rdition etc. But meurement of ll thee prmeter in plce i quite few prticulrly in ny developing country. There re lo locl chnge in ET 0 on the bi of ditnce from the wether ttion (Hubbrd, 1994; Pielke et l., 2000) nd proper integrtion of different climtic prmeter re required which lo ffect the ccurcy of ET 0 (Meek nd Htfield, 1994; Allen, 1996). Vriou method for clcultion re there mong which pn evporimeter nd ome ET model ue only temperture nd thu re le complex (Mgliulo et l., 2003). The Hrgreve eqution lo need only minimum nd mximum temperture (Hrgreve nd Smni, 1985) nd extrterretril rdition (Drooger nd Allen, 2002). Thu ET 0 cn be meured by vriou model nd method by different wether prmeter (Thornthwite, 1948; Penmn, 1948; 1

2 Prietley nd Tylor, 1972; Hrgreve, 1994; Hrgreve nd Allen, 2003). Allen et l., (1998) developed model for ET 0 which w publihed by the Food nd Agriculture Orgniztion of the United Ntion Penmn Monteith (FAO56-PM) by uing hypothetic reference crop which i pproved for the rid nd humid climtic condition. Preent tudy involve the ET 0 computtion nd nlyi of vrition for whole Mdhy Prdeh with prmeter like minimum nd mximum temperture, humidity, wind peed, unhine nd olr rdition for 30 yer (1971 to 2000). Study Are The tudy re lie in Mdhy Prdeh which extend from to N ltitude nd from to E longitude with n re of 443,000 km 2. Thirteen ttion tken for the tudy re Khndw, Nimch, Gun, Stn, Nowgong, Bhopl-Birgrh, Hohngbd, Pchmrhi, Sgr, Seoni, Jblpur, nd Umri. The tte of Mdhy Prdeh h ubtropicl type of climte. It h dry nd hot ummer nd cool winter. The verge rinfll i nerly 1025 mm which decree from et to wet (Figure1). Figure 1: Study re 1. Dt nd Methodology 1.1 Etimtion of ET 0 with Penmn-Monteith For clculting the ET 0, ome climtic ttion dtet were ued in the tudy. Different climtic vrible like minimum nd mximum ir temperture, reltive humidity, wind peed nd unhine durtion of 30 yer (1971 to 2000) were conidered. Averge monthly dtet hve been ued for etimting the verge monthly ET 0 tken from the Wter Development nd Mngement Unit nd the Climte Chnge nd Bio-energy Unit of FAO, The Penmn-Monteith model w formulted on the bi of hypotheticl green gr reference urfce in which ce the height of the gr i preumed to be 0.12m with urfce reitnce of 70 m -1 nd with n lbedo of 0.23 (Allen et l., 1998). It h been pproved by Food nd Agriculture Orgniztion (FAO- 56). Penmn-Monteith eqution re given below in equence: ( Rn G) ( ) u2 ( e e ) ET T (1) (1 0.34u ) 2 2

3 ET = reference evpotrnpirtion (mmd -1 ); 0 R n = net rdition t the crop urfce (MJm -2 d -1 ); G = oil het flux denity (MJm -2 d -1 ); = pychometric contnt (KP C -1 ); T = the men of the monthly mximum nd minimum ir temperture ( C); u 2 = wind peed t 2 m height (m -1 ); e = turted vpour preure (KP); e = ctul vpour preure (KP); = lope vpour preure curve (KP C -1 ) Slope of turtion vpour preure ( ) The lope of the reltion between turtion vpour preure nd temperture D i required for clculting reference evpotrnpirtion. At given temperture, the lope i given by: 17.27T exp T T (2) Atmopheric Prmeter z P (3) 293 P = tmopheric preure (KP), Z = elevtion bove e level (m) c p P x10 P (4) c p pecific het t contnt preure, (MJ kg -1 C -1 ) = = ltent het of vporiztion, 2.45 (MJ kg -1 ) = rtio moleculr weight of wter vpour/ dy ir = Air Humidity 17.27T e ( T) exp (5) T e(t) Stnd for the turtion vpour preure t the ir temperture T [kp] 3

4 1.1.4 Actul vpour preure RH mx RH min e T min e T mx e (6) 2 = turtion vpour preure t dily minimum temperture [kp], e T min e T mx = turtion vpour preure t dily mximum temperture [kp], RH mx = mximum reltive humidity [%], RH = minimum reltive humidity [%]. min Net rdition (Rn) Rn Rn Rnl R = incoming net hortwve rdition nd n R ( 1) n R Rnli the outgoing net longwve rdition. (7) (8) = lbedo or cnopy reflection coefficient for the reference crop [dimenionle], R = the incoming olr rdition (MJm -2 d -1 ); in ce net olr rdition i required to be clculted while computing ET 0, fixed vlue of 0.23 i conidered for the lbedo. n R b R N, b = the frction of extrterretril rdition reching the erth on cler dy (n = N), R = extrterretril rdition (MJm -2 d -1 ); (9) n = reltive unhine durtion, N 24(60) R Gcdr in( )in( ) co( )in ) (10) G = olr contnt = MJ m -2 min -1, c d r = invere reltive ditnce of Erth nd Sun, = unet hour ngle (rd), = ltitude (rd), = olr declintion (rd); 4

5 R e Ro 4 4 ( T mx ) ( Tmin ) Rnl 2 35 (11) = Stefn-Boltzmnn contnt [ MJ K -4 m -2 dy -1 ], T = mximum bolute temperture [K = C ], mx T min = minimum bolute temperture [K = C ], R = reltive hortwve rdition (limited to 1.0), Ro Wind peed For the djutment of the wind peed dt obtined from intrument which i plced t elevtion other thn the tndrd height of 2 m, following clcultion i done: 4.87 u2 u z (12) ln67.8z 5.42 u z = meured wind peed t z m bove ground urfce [m -1 ], z = height of meurement bove ground urfce [m]. RESULTS Different climtic vrible of minimum nd mximum temperture, humidity, wind peed, unhine durtion nd rdition hve been hown for 30 yer from 1971 to The minimum temperture i highet in My-June up to September fter which it trted to decree. The minimum temperture vrie from 28.3 C in June (Nowgong) to 7.5 C in December (Nowgong nd Pchmrhi). The verge monthly mximum temperture i highet in the month of My with more thn 40 C nd little down from June to Augut nd gin little pek in September up to 35 C nd lowet in Jnury (22.4 C) in Pchmrhi. Khndw i howing highet mximum temperture. The reltive humidity i highet or mximum from June to September of nerly 95% in June, with Jblpur hving the highet while lowet humidity i found from Mrch to April with Indore hving the lowet (13.3% in April). Wind peed i mximum from April to Augut. It vrie from 50 km/dy in November-December to 455km/dy during June-July with Indore hving ditinctively the highet wind peed (458 km/dy). The mximum nd minimum unhine hour vrie from 10.2hr/dy in Februry when ky remin very cler to le thn 5hr/dy during the monoon period (minimum of 1.34 hr/dy in July) of overct ky repectively. The olr rdition i highet in My of round 25 MJm -2 d -1 in Nimch to round 12 MJm -2 d -1 in Umri during July-Augut (Figure 2 -f). () 5

6 (b) (c) (d) 6

7 (e) (f) Figure 2: (-f): Averge monthly climtic vrible from 1971 to 2000 Khndw=1, Indore=2, Nimch=3, Gun=4, Stn=5, Nowgong=6, Bhopl-Birgrh=7, Hohngbd=8, Pchmrhi=9, Sgr=10, Seoni=11, Jblpur=12, Umri=13 nd Men of ll ttion=14. The men monthly ET 0 w clculted with help of FAO 56 Penmn-Monteith method with 13 ttion of entire Mdhy Prdeh to how the vrition of ET 0 throughout the tte which i n extremely importnt vrible to be conidered for griculture purpoe. The reult indicte tht ET i highet in the month of My (11.77 mm dy -1 ) in Indore to lowet in the month of December (2.2 mm dy -1 ) in Jblpur. My i the month of highet rte of ET for ll the 13 ttion which in decending order re mm dy -1 in Indore, 9.64 mm dy -1 in Khndw, 8.54 mm dy -1 in Nimch, 8.32 mm dy -1 in Bhopl-Birgrh, 8.2 mm dy -1 in Gun, 7.62 mm dy -1 in Sgr, 6.87 mm dy -1 in Stn, 6.76 mm dy -1 in Jblpur, 6.67 mm dy -1 in Nowgong, 6.56 mm dy -1 in Seoni, 6.46 mm dy -1 in Hohngbd, 6.32 mm dy -1 in Umri nd 6.07 mm dy -1 in Pchmrhi. The men of ll 13 ttion for the My month i 7.68 mm dy -1. The rte of evpotrnpirtion i oberved to be highet in the month of April to June in Mdhy Prdeh. Thu wter requirement for crop re more during thi period (Tble1). 7

8 Tble1: Averge monthly ET 0 (mm dy -1 ) Sl no. Sttion nme Jn Feb Mr Apr My Jun Jul Aug Sep Oct Nov Dec 1 Khndw Indore Nimch Gun Stn Nowgong Bhopl- Birgrh Hohngbd Pchmrhi Sgr Seoni Jblpur Umri Men Concluion The tudy involve the computtion nd nlyi of one of the mot importnt climtic vrible, i.e. evpotrnpirtion for entire Mdhy Prdeh. Thi tudy how the monthly ET vrition which i very ueful for nlyi of vriou irrigtion pln, crop wter requirement etc. The diprity of ET in different prt of the tte need different quntity of wter upply ccording to the demnd of the re. The region of Indore require greter upply of wter to the nerby griculturl field during My ET i highet there. While Pchmrhi being the hilly re, hve lowet ET nd need le wter upply to the crop during thi month. FAO-56 Penmn-Monteith method i globlly ccepted nd extremely importnt empiricl model to clculte ET 0 which i lo n importnt climtic prmeter. Thi reult cn give n overll picture of ET 0 of the tte of Mdhy Prdeh for further wter reource nd mngement pln. ACKNOWLEDGEMENT The uthor thnkfully cknowledge CSIR-UGC for providing finncil upport in the reerch. REFERENCES Allen RG (1996). Aeing integrity of wether dt for reference evpotrnpirtion etimtion. Journl of Irrigtion nd Dringe Engineering ASCE 122(2) Allen RG (2000). Uing the FAO-56 dul crop coefficient method over n irrigted region prt of n evpotrnpirtion intercomprion tudy. Journl of Hydrology 229(1 2)

9 Allen RG, Pereir LS, Re D nd Smith M (1998). Crop Evpotrnpirtion-Guideline for Computing Crop Wter Requirement. FAO Irrigtion nd dringe pper 56, United Ntion Food nd Agriculture Orgniztion, Rome. Drooger P nd Allen RG (2002). Etimting reference evpotrnpirtion under inccurte dt condition. Irrigtion nd Dringe Sytem Fiher JB, DeBie TA, Qi Y, Xu M nd Goldtein AH (2005). Evpotrnpirtion model compred on Sierr Nevd foret ecoytem. Environmentl Modelling nd Softwre 20(6) Hrgreve GH (1994). Defining nd uing reference evpotrnpirtion. Journl of Irrigtion nd Dringe Engineering ASCE 120(6) Hrgreve GH nd Allen RG (2003). Hitory nd evlution of Hrgreve evpotrnpirtion eqution. Journl of Irrigtion nd Dringe Engineering ASCE 129 (1) Hrgreve GH nd Smni ZA (1985). Reference crop evpotrnpirtion from temperture. Applied Engineering in Agriculture 1(2) Hubbrd KG (1994). Sptil vribility of dily wether vrible in the high plin of the USA. Agriculturl nd Foret Meteorology Hunker DJ, Pinter PJ nd Ci H (2002). Alflf bl crop coefficient for FAO-56 procedure in the deert region of the outhwetern US. Journl of Trnltion ASAE 45(6) Mgliulo V, d Andri R nd Rn G (2003). Ue of the modified tmometer to etimte reference evpotrnpirtion in Mediterrnen environment. Agriculturl Wter Mngement Meek DW nd Htfield JL (1994). Dt qulity checking for ingle ttion meteorologicl dtbe. Agriculturl nd Foret Meteorology Penmn HL (1948). Nturl evportion from open wter, bre oil nd gr. Proceeding of the Royl Society of London Serie A Pielke RA, Stohlgren T, Prton W, Doeken N, Moeny J, Schell L nd Redmond K (2000). Sptil repreenttivene of temperture meurement from ingle ite. Bulletin of the Americn Meteorologicl Society AMS 81(4) Ping X, Xiohong C nd Zholi W (2009). Comprion of Actul Evpotrnpirtion nd Pn Evportion. Act Geogrphic Sinic 64(3) Prietley CHB nd Tylor RJ (1972). On the ement of the urfce of the het flux nd evportion uing lrge cle prmeter. Monthly Wether Review 100(2) Thornthwite CW (1948). An pproch towrd rtionl clifiction of climte. Geogrphicl Review Wu SH, Yin YH, Zheng D nd Yng QY (2006). Moiture condition nd climte trend in Chin during the period Interntionl Journl of Climtology 26(2)