1,.,+ 1,//,1 + +,,,1 2 Konya et al.,. Yang and Koike,/ locally calibrated Ångtröm model AMeDAS,., - : Key word: nowpack outflow, nowmelt, percolation, modeling +,0 + JR + 3/,+2+, 2/, JR 3- +./,.13 : Centro de Invetigación en Ecoitema de la Patagonia Francico Bilbao..3, Coyhaique, Región de Ayén, Chile
256 1,.,+ +33. Hock,,- Hock +333,. potential clear-ky direct olar radiation Konya et al.,.,1 2 Pellicciotti et al.,/ Kuta et al. +33. Konya et al.,.,. +302 ; Colbeck, +312 ; Colbeck, +313 ; Marh and Woo, +32/, Dunne et al., +310 ; Bengton, +32, ; Albert and Krajeki, JR +332-0 m; + Marh and Woo, +32. ; Nomura, +33.
1,.,+ 257, +, - +, + - -, cm,2, +1 +,11 mm,2 - + + m + - O : Ih : AMeDAS A :.,. Sm : Rg : Ng : cm Aw : -, Fig. + Topographical map of the tudy area (contour interval : + m). + O:Ohirakawa, Ih:Irihiroe AMeDAStation, A: Mt. Aakuadake, Sm: Mt. Sumondake, Rg:Rokujuri-goe pa, Hg:Niigata Local Meteorological Obervatory, Aw: Wakamatu Weather Station. QMQRQHQLQPQC QM QR QH QL QP QC QC + QM, Jm lf + --.. Jkg M mm + MQMlF,-b QR.,- a.+ m QH QE,1 +, 3 +33.,2. - - 1 - QHCHrC T T u -+ p z z,1 2 Q C rl. 0,, p e e u E E a z z
258 1,.,+,,.,1 +,,2. Fig., Variation in daily mean air temperature, daily mean global radiation, daily precipitation and now depth and now water equivalent at,. : h in each day from December,1 to April,2. C C H E r kg m C J kg K - + + p l + a T T zm C C z e e zm +,, z H E p a Jkg z p hpa hpa u zm m C C k ln zz H E +33-
1,.,+ 259 k.. z m z z.. m, m /0. m, m Q, m u z 10. m Q r C T P a P w w w r u a r kg m C - w w + + w r u u lnz lnz ln z D lnz mm h T + z a a w D m Sprung +33-, m - z, Wm,, +. 1 Wm, 1/ Wm,,, Wm z, z. z.. m, C C,.,+ + 2.- - H E,- a.+ m, +0., -../ -- Jkg K, Wm T P P Fig. - - Daily heat balance component for urface nowmelt at Ohirakawa.
260 1,.,+ 0. +, - E. A / 0, a E w, t+ w, t m, t w, t+ w, t, t P r P R r m. Fig.. Schematic diagram of liquid water balance component within nowpack, which can a# ect the meaurement of now water equivalent by a now pillow. b A A A t+ t,0 ;,1,1 2 H H t + R,2-1.,. m, t R RR R R t m, t r, t m : R R H H P / A R H H P P -,. 0 mm h + t w, t+ w, t, t r, t, a + 2 R - b A m in m
1,.,+ 261 A out / C A in A R / D out A A, out +. kg m + kg, / B + m / A: B: C: D:. 1 Fig. / The procedure of obtaining the outflow from the bottom of a nowpack uing the temporal variation in now water equivalent at Ohirakawa. A: the torage change in liquid water within nowpack obtained by Eq. ( 2), B: the reult of deletion of the negative value in the torage change, C: the meltwater component in the outflow from the bottom of a nowpack, D: the outflow from the bottom of a nowpack. Note that the reolution of each value until 1 April i lower than that ince then.
262 1,.,+ / +. 1 +/ : Ångtröm Yang and Koike,/ locally calibrated Ångtröm model / D min Yang and Koike,,/. K R a a DD a DD if DD + a if DD. D min, Ret AMe- D 0 min DAS a a a a a.,310 a..++3 a.,/. a. +2-1 Yang and Koike,/,1 2,2 3 0 km AMeDAS, a.-0+- a.,2, a. +0 a. +02. 0.+, r 3. Ångtröm ÅngtrömPre-., cott K W m R Konya et al., d et Wm, d et +, -. -.., +, -. +, Wm +, -,.
1,.,+ 263 0 Fig. 0 AMeDAS The relationhip between global radiation oberved at Ohirakawa and that etimated with duration of unhine at Irihiroe AMeDAS tation. 1B 3-. +, r 3-. a..-. b+-.,+ c.+.3 1 C 1D 1D, r 3..- QMaKdbTac,., QM W m Ta, Kd Wm a,b,c Darcy + + R m D m h m k w + m a..-- b++. 21 c-.. +/ R k whd 1A h 1B mm R + R mm h -,. k R d dtmprer M, Pr, E + mm h k
264 1,.,+ 1 Fig. 1 : A B :, + C D W m mm h Comparion of urface melt rate etimated uing the temperature-radiation index melt model and that oberved with the heat balance method. Top: Temporal variation (A) in, and the relationhip (B) between melt rate etimated uing the melt model with oberved global radiation and oberved melt rate. Bottom: Temporal variation (C) in, and the relationhip (D) between melt rate etimated uing the melt model with etimated global radiation and oberved melt rate. h,. D k E 2A M P I k r t R RR exp+ k I I exp+ k R +- t t+ w, t w, t w t R / 2,. + k h
1,.,+ 265 2 A: +331 k D,. B:,2 k D C:,2 k FD Fig. 2 The relationhip between dicharge coe$ cient and now depth, and that between dicharge coe$ cient and poitive degree-day. A: The k D relationhip at Jozankei in the melt eaon of +331 (Nakatugawa et al.,,.), B: The k D relationhip at Ohirakawa in the melt eaon of,2, C: The k FD relationhip at Ohirakawa in the melt eaon of,2. I 2B w +32- k. mmh + +2 R R, k k.11- D r. 1-03 2B k k,. D cm,. 2A k degreeday k D 2 A k 2B k D
266 1,.,+,, Firt Dicharge Index FD - FD k 2 C k / FD day k FD k k, 2, k./-, FD+0. 2/ r. 2/+1 M / P k r FD +,. +2. mmh + 3A M,, : 3B, k k,. k R,.
1,.,+ 267 3 Fig. 3 A: B: k FD k D Variation in outflow from the bottom of a nowpack etimated uing the linear reervoir model and that obtained from the change in now water equivalent. A: Etimate uing the linear reervoir model with oberved urface melt rate, B: Etimate uing the linear reervoir model with etimated urface melt rate. The thick black and dotted black line indicate the etimate uing the linear reervoir model with the k FD relationhip and that with the k D relationhip, repectively.
268 1,.,+ R 0 k Konya et al.,. Yang and Koike,/ locally calibrated Ångtröm model AMeDAS,. k,. FD, k k D k - FD,. +331 2 A k D +332 2 k D MTS k D 2A k FD FD,. Albert, M. and Krajeki, G., +332: A fat, phyically baed point nowmelt model for ue in ditributed application. Hydrological Procee, +,, +23 +2,..
1,.,+ 269 Bengton, L., +32, : Percolation of meltwater thr- cover,. A imulation model. Water Reource Reough a nowpack. Cold Region Science and Tech- earch,,, +20/ +21.. nology, 0, 1-2+. Marh, P. and Woo, M.K., +32/ : Meltwater movement Colbeck, S.C., +312: The phyical apect of water in natural heterogeneou now cover. Water Reflow through now. Advance in Hydrocience, ++, ource Reearch,,+, +1+ +1+0. +0/,0.,. : Colbeck, S.C., +313: Water flow through heterogeneou.2-1 now. Cold Region Science and Technology, +,.,. -1./. Nomura, M., +33. : Studie on the delay mechanim Dunne, T., Price, A. and Colbeck, S.C., +310 : The gen- of runo# to nowmelt. Contribution from the Intieration of runo# from ubarctic nowpack. Water tute of Low Temperature Science, -3, +.3. Reource Reearch, +,, 00102/. Pellicciotti, F., Brock, B., Straer, U., Burlando, P., +33. :,.,1,+3. Funk, M. and Corripio, J.,,/: An enhanced temperature-index glacier melt model including the Hock, R., +333: A ditributed temperature-index ice- hortwave radiation balance: development and and now-melt model including potential direct teting for Haut Glacier d Arolla, Switzerland. Jouolar radiation. Journal of Glaciology,./, ++ +++. rnal of Glaciology, /+, /1- /21. Hock, R.,,-: Temperature index melt modelling in mountain region. Journal of Hydrology,,2,, +.,0 : JR ++/. :,- +32- : / +,- +,/. ++2 +,-.,1 :,, : 0. 0/ 0+/.,- +/0 +0. +302 :,0 : A,0 1220.,, 102. +33. : : +33- :,.,0. +01 pp. Yang, K. and Koike, T.,,/: A general model to Konya, K., Matumoto, T. and Narue, R.,,.: Sur- etimate hourly and daily olar radiation for hyface heat balance and patially ditributed abla- drological tudie. Water Reource Reearch,.+, W tion modelling at Koryto Glacier, Kamchatka Pen- +.-, doi: +. +,3 /,/ WR -310. inula, Ruia. Geografika Annaler, 20A, --1-.2.,-a : Kuta, W.P., Rango, A. and Uijlenhoet, R., +33. : A imple energy budget algorithm for the nowmelt,-.0. runo# model. Water Reource Reearch, -, +/+/ +/,1. Marh, P. and Woo, M.K., +32. : Wetting front ad-,-b : 0/ ---+0. vance and freezing of meltwater within a now
270 1,.,+ Etimation of outflow from the bottom of a nowpack uing a combination of a temperature-radiation index nowmelt model and a percolation model Takane M, Katuhia K, Aako T -O + +, ATSUMOTO AWASHIMA OGARI HTA and Makoto S, HIMAMURA + ) Reearch Center for Natural Hazard and Diater Recovery, Niigata Univerity, Ikarahi,-no-cho 2/, Nihi-ku, Niigata 3/,+2+,) Diater Prevention Reearch Laboratory, Reearch and Development Center, Eat Japan Railway Company, Nihin-cho,-chome.13, Kita-ku, Saitama 3- +./ Preent addre : Centro de Invetigación en Ecoitema de la Patagonia, Francico Bilbao..3, Coyhaique, Región de Ayén, Chile Abtract: A imple modeling method for etimating the outflow from the bottom of a nowpack during the pring melt eaon i propoed; thi model can be ued in ditributed application for preventing nowmelt-induced landlide hazard in mountainou region. A temperature-radiation index melt model (Konya et al.,,.) i applied to the reult of heat balance obervation carried out at Ohirakwa in Niigata Prefecture in the winter of,1/2 in order to calibrate the coe$ cient of the model. Etimated global radiation uing a locally calibrated Ångtröm model (Yang and Koike,,/) with duration of unhine at the nearet AMeDAS tation can be ued a an input to the melt model. The percolation of water through a nowpack i modeled uing a linear reervoir with a dicharge coe$ cient that varie with a change in the now depth (Nakatugawa et al.,,.). Moreover, a new parameterization of the dicharge coe$ cient with poitive degree-day i applied for thi percolation model. It i found that thi combination of a melt model and a percolation model yield good etimate of outflow from the bottom of a nowpack at + -hour interval in the latter tage of the melt eaon when the following three input data are available : air temperature, global radiation (or duration of unhine), and rainfall intenity.,3 +,,3,+ - 3,+ 0.,+ 0.,++ + +/