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<br />.. <br /> <br />EJ. BrOIl", WE. a.uJ.r.lrf I Journal of Hwlro'''8Y 2/6 (J999) JJ7-J-U <br /> <br />'" <br /> <br /> <br />,., <br /> <br />EJ B",~... WE. &mJsIt,~ /Jooma/ uf H.,.I,,""'1W !l6(999) JJ7_1-14 <br /> <br />" <br /> <br />" <br /> <br />--.. <br /> <br /> <br />.i <br />--~ <br />-------~ <br />_oooo__~ <br /> <br />" <br /> <br />::=:::::: <br /> <br />" <br /> <br />50 <br /> <br />112 <br />:; <br />i <br />. . <br />~ <br />I <br />u <br /> <br />I <br />-------r <br /> <br />.. <br />C <br />~30 <br />~ <br />c <br />" <br />~ <br />0" <br /> <br />E 12 <br />! <br /> <br />r <br /> <br />. <br />. <br />. <br />. . <br />'l <br />I <br />u <br /> <br />---------...... <br /> <br />---------~. <br />I <br /> <br /> , --.... , --i. <br /> . . . . . ! ! . . . . . - ! <br />,-) nme(hrl' '" Tlml(hrl) <br />" " <br /> - -... <br />I " " -~ <br /> ~ 112 ~ <br />En <br />! - --- - - -..- <br /> . <br />i -00----1 i -------1 <br />. . -------- . <br />~ , <br /> .u__u___.. . 00________.., <br />~ ! . '"1 <br />u u <br /> i - -... <br /> --f! , <br /> , . . . . . ! ! <br /> . . . ":I :: ! ! <br />t,l Tlml(hr.) t~ nml(hrl' <br /> <br />10 <br /> <br />" <br /> <br />20 3Q .. <br />Tipping Bucket Rainlall (mm) <br /> <br />.. <br /> <br />50 <br /> <br />A,. 4. Re1aliv' Kl:W'IoCy of lippialllv<:lut aDd 1Ii1IsWld 8"'1"'- showi"l UIlder-recordi.., in lbo stilhund pu&a for 1M Iarp cnPll, <br />protrAblybecauscof...indclfccu. <br /> <br /> <br />probably be reduced further with commeR:ial mass <br />production. Even with some mark.up. this suggests <br />that the purchase price for a manufactured stillstand <br />gauge would be very much less than Ihal of WI auto- <br />matic rain gauge - which may COSI a few bundred <br />dollars. <br />TIle stillstand lines on the X-ray films were evalu- <br />ated by eye after film development. This process <br />might be auwmaled by digital scanning of the film <br />record with r.he resultin, data being input to It compu- <br />terroutinefocobjecliverecognitionoftllinfallevent!i. <br />Fig. 2 illustrates the nature of the output of still- <br />stand gauges. The left graph is a nine-day period of <br />cumulative rainfall from a tipping bucket recording <br />gauge, and the other plots arc the corresponding <br />records of three nearby slillsland gauges. The major <br /> <br />, C . " "",i~ofr.lill5land;mdlippin,buckcl"'in,:w,e.fromdiJJe'enl.ile..[bshedl;ne$indic..elhc...,m.led <br />Fig, 3, I~J~( ), umplUlsono OW"~_ <br />corrdalionlink,guh<",'een",infolloventsrecordeli""theIWO,Blllelype. <br /> <br />minless periods are clearly evident as lines in me still- <br />stand records. which indicate some spatial varialion of <br />the first rainfall event and a lensing OUl of me second. <br />Stillsland gauges will always have an evenl resolution <br />limitation for small rainfall events. where "small" <br />depends on lile gauge vertical exaggeration. For <br />example. the small 5e1;ond rainfall event in Fig. 2 <br />may not lense out completely in gauge C, so whal <br />appears as a single line (second line up) may in fact <br />be two closely spaced lines. <br /> <br />3. Gauge accuracy <br /> <br />1be accuracy of rainfall event measurement with <br />stillstand gauges is detennilled largely by the selected <br />