w» wz, 11«1y(2009) Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1, (2009), pp. 27~38»/ yk v q d l y Á y*áy ³Á½ w» w / y (2008 12 20 ; 2009 1 20 ; 2009 1 30 ) Principles and Applications of Multi-Level H 2 O/CO 2 Profile Measurement System Jaeill Yoo, Dongho Lee*, Jinkyu Hong and Joon Kim Department of Atmospheric Sciences, Yonsei University/Global Environment Laboratory (Received December 20, 2008; Revised January 20, 2009; Accepted January 30, 2009) ABSTRACT The multi-level profile system is designed to measure the vertical profile of H 2 O and CO 2 concentrations in the surface layer to estimate the storage effects within the plant canopy. It is suitable for long-term experiments and can be used also in advection studies for estimating the spatial variability and vertical gradients in concentration. It enables the user to calculate vertical fluxes of water vapor, CO 2 and other trace gases using the surface layer similarity theory and to infer their sources or sinks. The profile system described in this report includes the following components: sampling system, calibration and flow control system, closed path infrared gas analyzer (IRGA), vacuum pump and a datalogger. The sampling system draws air from 8 inlets into the IRGA in a sequence, so that for 80 seconds air from all levels is measured. The calibration system, controlled by the datalogger, compensates for any deviations in the calibration of the IRGA by using gas sources with known concentrations. The datalogger switches the corresponding valves, measures the linearized voltages from the IRGA, calculates the concentrations for each monitoring level, performs statistical analysis and stores the final data. All critical components are mounted in an environmental enclosure and can operate with little maintenance over long periods of time. This report, as a practical manual, is designed to provide helpful information for those who are interested in using profile system to measure evapotranspiration and net ecosystem exchanges in complex terrain. Key words : Multi-level profile system, H 2 O/CO 2 concentrations I. k k y d w œ y w v d Ÿ w š. œ w» w»» d w»» 3 twt œ»» k ( 2-3 ) ew ( 10-20z) t» d w.»» e ƒ,»ƒ w t d k y tw. w œ»» l w e» w» ù w œ l d ù» d w. * Corresponding Author : Dongho Lee (dlee@ieg.or.kr)
28 Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1 ù x t» yk œ l d ¾ j š d k. k y x d ù d ƒ. jƒ ûš w z w j. ü w» y ( ) v (Storage) š w d w» s d w ƒ v w. w l d» s y l w w ( 1).», h ρ v Storage = ------- dz t 0 (1)» h, ρ v», t, z ùkü. w» d l yƒ w ƒ mw œ l» y w yw» w. h ρ v Storage ------- dz h ρ v = -------- t t 0 (2) w w»( yk ) s y v w» d l l d. w wš»ƒ w jƒ j ù ù ƒ j y»ƒ y p w (Bradford et al., 2001). w w 50%¾ w sƒw w w w (Finnigan, 2006), p» w w z ƒ w ù 30-60 ³ w z ƒ j» w. š w ù v» w» w ù k y w w. w z w k y w w w (Hong et al., 2008).,» e. ET = h 1 -- ρ v ------- dz V t 0 + h 1 ρ v -- wz ( )------- dz + V z 0 + I III 1 -- ( w ρ V v ) h II h 1 ρ v -- uz ( )------- dz V x 0 (3)» V d œ t, x s³ t ww w ùkü, u w ƒƒ s t t ùküš s³ ùkü. Iw w, z IIIw txw (Lee, 1998). ρ v h 1 -- wz ( )------- dz = w( h)ρ (4) V z v ( h) ( ρ v ) 0» < > s³» w z d w» w» sƒ v w. r» d l( w v q l w ) w» s d ù x k y yw d w v w». š p w» e w, y v q l y w w ü t. š w v q l Campbell Scientific Inc. wš x» / yw q w Ÿ d š l. w v q l y š v q l» y wš w Campbell Scientific Inc. l ƒ» l» š k» s, yk k y d ww ù zwš w» e w ww. II. v q l 2.1. v q l v q l» v l, IV
Yoo et al.: Principles and Applications of Multi-Level H 2 O/CO 2 Profile Measurement System... 29 Fig. 1. A Diagram showing the Main Components of Profile System and the Direction of Airflow. l,» l, sz»» (IRGA), œrv š l» (Fig. 1). v l e mw œ» w»» ü, l y š» w»» w w w. l» sw v / kwš,»» x» y ƒ» w, m w w. d y» d ww l w yw f ( ) ü ew w (Fig. 2). š v q l Appendix. 2.2. v l v l v q l l ƒ œ» ¾ w p œ» e. p š s p p gs (copolymer) gq ü w. ü p mw» yk ƒ y w š, w p ƒ w w w w. s p» p ( ). p ¼ ü w w» w( Fig. 2. The Profile System in a Protective Metal Casing installed at Conifer Forest in the Gwangneung KoFlux Site. Fig. 3. The Air Intake Assembly. d e w yw» w) v w. œ» e 3/8 e 0.305 e ü 1m ¼ l p q v (Fig. 3), œ»ƒ ó (rain diverter) e(coarse) vlƒ. ƒ ü w. œ» e Swagelok w 7µm vl 0.016 e w. ù»
30 Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1 w» þƒ w»ƒ» w 0.5W lƒ e. lü w w w. yw j»( ) w œrv x, v l, ¼ š š w lü d» 50% w. û w,» p d w v w y w. l» 50% k w» ƒ (œ» ƒ w ) l ü» rv œ y w w.»»» v û w p ü ¼» x k. Dalton e yw» w, yw» w ƒ» -» sww - w w.» û û ƒ p ü û x ù. l ü û w d ƒ ƒw. w, ƒ w sx k w» w w. ƒ d ƒw š ƒ s³ d w j. ƒƒ œ» e p mw» (, manifold).» k œ»»» ü š k œ» œrv(» ) ý v œ»ƒ w l ü. l» y w dw w. k wù œ»»» ü š œ» w w» w w w (Fig. 4). Fig. 4. Miniature Face Mount Solenoid Valve(A) (Lee Co.) and Custom Manifold (B). ƒ œm sp œ» š sp z œrv s sp œm»» v. œm yw v w» m y g œ» y z sx jš d w y., 0.016 e w œ» 1.3SLPM(Standard Liter Per Minute) š»» v ü 49.26kPa w, yk» ƒ œ» y ú 99.95% yƒ Ÿ e l yk 6 ƒ.» 99.4% yƒ. w w»» t r (drift) w yw š
Yoo et al.: Principles and Applications of Multi-Level H 2 O/CO 2 Profile Measurement System... 31 Fig. 5. The Schematic of Valve Switching and On/Off System (from 8 Level CO 2 and H 2 O Profile System Operation Manual, Campbell Scientific Inc., USA).» yk» y w. y» ƒ y ( l 10 ) d ƒ w w g l w., 0.06 µmol/mol w yk y d w ƒ w. 2.3.» l l, Ÿw ù Ÿ, k zy w» r ù y w» w. l ƒ w ƒ» ( yk w w» (» ), t (», yk )» )»» v ü» w. v q l»» (absolute)»» (reference)»/ yk yw vlù» w. mw» yw vlƒ sy w w y w. r w, ƒƒ Decarbite ( yk ) Drierite (» ) 500ml s e p(polycarbonate)»ƒ l ù» œ w. l v l w v l wì» w e (Fig. 5). k e(selector) z w k»w sp ƒƒ»» š œm sp y. wù s d
32 Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1 q l Licor w LI-6262ù LI-7000 w.»» -v q l s z w - š d» y l» ü w y w w. w»» y»ƒ e v d w, d w e y w» w. Fig. 6. SDM CD16S Flow Control Module. l v l l w w w.»» ü w w. sp ywvl š sp». v l» fp sp SDM CD16S w (Fig. 6).» ù w w eƒ e p w v š j ù w s mw»»» v ü» w w. 14 e» kw» w wš 16 e s z rv w» w w. ON» ywvl s z w š OFF s z w š» w w.» û» w, s (9 )ƒ y y. s v ƒ y y.» œrv ww ü š, w ƒ» s mw»» v ü. w l ü v w. 2.4.»»»»»»( yk ) d w»» Campbell v 2.5. l» l»»» ƒ œ/ wš l w w w. Campbell w v q l CR23X-TD CR3000 l» w, x q w l CR23X-TD w. CR23X-TD l»»» xy (»/ yk, v ) 250milliseconds d wš, wš, ƒ d s³ 30 w, w. 30 s³ w l»» yk y»» xz (least square linear fit) w w, ƒ ƒ» d x w w w w. d, š y l» w, d y w ƒ w. w, ƒ 10 y (, 10 d w) (8 ) d w 80. w ƒ y 6 y». y ù 4 d š d s³. w y d p w d (» 1.3 SLPM, v 49kPa,» (manifold)»» w p j» ¼ ) w w» w yw w w.
Yoo et al.: Principles and Applications of Multi-Level H 2 O/CO 2 Profile Measurement System... 33 d y w jš m(systematic) ƒ w yw» w d 1, 3, 5, 7, 8, 6, 4, 2. w (»»/ yk ) yw» w w» z (memory effect) z w. 24 ( ) l» v 5» n w» yk r d wš z t yk» 5 n w d w z t w. w w l» ¾ d.» t d» w. 2.6. e lü», e, w vl w., d r,»», q, œrv š»w. l w» ƒ vlƒ yw e yw e š» w ew y w w. ƒ œ» e 7µm œ vlƒ (Fig. 7). 2.6.1. vl» ywvl» œ»ƒ m w yw» w ACRO50 vlƒ. z ep vlƒ, wù v ƒ œ, wù» ƒ œ, š vl» ù œ e. vl 50mm Fig. 8. Disposable Polypropylene Catridge Filter with 1µm Pore Size PTFE Filter Element. 1µm œ p barb fitting w (Fig. 8). 2.6.2. œrv œrv l œ» e l» e ¾ œ» x wš ü w., p š w z ƒ š y v w ü q(diaphragm) rv w. rv skwš w ew. vw y»ƒ œ ew. œrv m l» mw 0.5inch s p p w. s p p lü w y w»(buffer) w w» š l wì œ ¼ Fig. 7. Swagelok Inline Filter Holder with 7µm Sintered Stainless Steel Filter.
34 Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1 w. rv œ w e ƒ e w. w l ü» 50% w. w œrv w( ƒ k ) ù w( k ) w. l ü œ» d» 1.1~1.4SLPM. ƒ œ» e d œ» ü w w. 2.6.3.» yk sww» ƒ»» r d w» w v w (» ). w»»» ü 0 ppm d w w w. 1% ü yw š yk w» (t» )ƒ»» d w» w. t» yk ƒ d» yk w.»»»»» w»w.»» l w» (pressure regulator) w v w. 2.6.4.» yw v q l w œ» w» yk w yw v w.» œ»»» v ù»»» œ. yw wš t ƒ j» w ³ew xk œ. j» (mesh) tx 1 s e j» wš ƒ j, ƒ j w. p wš k w l k w w. yw y mw k w ƒ. w yƒ k w w»., œ» yw mw m (channeling effect)ƒ» z ƒ j w. yw, (Magnesium perchlorate, Mg(ClO 4 ) 2 ) Drierite yg p(cobalt chloride); yk, z(soda lime) Decarbite ƒ. 2.6.5. l v q l w y w w» w eƒ lƒ. l v q l q» q wì e. l» w» k. 2.6.6.» v q l d yw» w» wì d wš, e» d Integrated Silicon Pressure Sensor(Model: MPX4115A, Freescale Semiconductor, Inc.). y w» y. V out = V s P 0.009 0.095 ( ) ± ( pressure error Temp. Factor 0.009V s ) (5)» V s œ ( : V, V s =5.1±0.25VDC), P», V out (V). III. v q l y 3.1.», w d, š y l» w, l, ƒ y 6 y š z 4 d d s³.»»» y (mv)»», (,»»(slope) v (offset)) w yk ppm,» mmol/mol y.. CO 2 (ppm)=(co 2 [in mv] οffset) slope (6) H 2 O (mmol/mol)=(h 2 O[in mv] offset) slope (7)
Yoo et al.: Principles and Applications of Multi-Level H 2 O/CO 2 Profile Measurement System... 35 y»» v mw.» yk,»» 0.21ppm/mV, v 238.095mV,»»» 0.021mmol/mol/mV, v 238.095mV. š w 30 s³ w l»» yk y»» xz (least square linear fit) w w. 3.2. y 3.2.1. d» Fig. 9 2008 ƒ t ú Ÿ y d» y š.» s 7 w»» Fig. 9. Daily Variations of Water Vapor Concentration in Gwangneung Deciduous Forest on, (a) 13 January, 2008, (b) 18 April, 2008, (c) 14 July, 2008 (d) 30 October, 2008. Note that the y-scale of fig. (c) is different from the rest. The height of each level: level 1-0.1m, level 2-1m, level 3-4m, level 4-8m, level 5-12m, level 6-18m, level 7-25m, level 8-40m. Fig. 10. Daily Variations of CO 2 Concentration in Gwangneung Deciduous Forest on, (a) 13 January, 2008, (b) 18 April, 2008, (c) 14 July, 2008 (d) 30 October, 2008. Note that the y-scale of fig. (c) is different from the rest. The height of each level: level 1-0.1m, level 2-1m, level 3-4m, level 4-8m, level 5-12m, level 6-18m, level 7-25m, level 8-40m.
36 Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1 Fig. 11. Vertical Profiles of Three-Hour Averaged Water Vapor and CO 2 Concentration measured on 14 July, 2008. ƒ wš w y w ùkù. p, û t d» ƒ w ( t š d û ) (Fig. 9(c)). ù kù» y r 1 ƒ û» w y( z ƒ) š, 4 12~18 û š 10 12 z ƒw w. 7 w t 12 zw w ƒ š d w ƒ û. 3.2.2. d yk Fig. 10 2008 Ÿ y d yk y. 4 12 zw š 1 ƒ» w» x w š. œm t ƒ yk. w û t d yk ƒ j. Fig. 11 Fig. 10(c) ú d yk (a)/»(b) s y 3. wd ƒ f, k y w w» ƒ f» ( 2) s d k y y w. 3.2.3. / w x k k y e w w»/ yk v q d l x ù y k y w w v w w w w., Hong et al.(2008) Ÿ KoFlux d e»/ yk v q d l w œ d ù v w 1) k d» yk v w s w w y w š, 2) w w w w w š, 3) w œ»» d (20m 40m) š» yk ùkûš, 4) s ƒ
Yoo et al.: Principles and Applications of Multi-Level H 2 O/CO 2 Profile Measurement System... 37 ù v j š w v w 40m d v œ ù v w k y yw. wr»/ yk v q d l l» yk (inverse Lagrangian method) ww» y ù v ƒ sw w (, Raupach, 1989; Denmead et al., 2005; Katul et al., 1997). ù ƒ (near field) (far-field) w z y w»/ yk v q ü d ü.»/ yk v q d l y w» / yk v q l ü, ƒ y dw x wš w w ù(, Coppin et al., 1986; Haverd et al., 2009), w d ù v wš w x sƒw y (, Baldocchi et al., 1997). y» ( y 1-8-3) w. š w œw Campbell Scientific. Inc. Senior Application Engineer Edward Swiatek w. d» w y., x ew ù œ w yk k y (Net Ecosystem Exchange, NEE) dw» w s (advection) (storage)w z yw w. š» w ù d w v w.» yk s œ v k e e» v q d l( w v q l) w d. l» d»»»» e wù w w»»» / /. x v k d wì š v q l e (Campbell Sci. Inc.) /q w l ƒ dy ww w l. w» w» / yw q 2005 l Ÿ y e e w v q l e/ w w», x w. x k k y d w v q l,, y w w. Appendix: Specification š wš v q l». œ» e : 8 d : 40m v : 4Hz d s³ : 30 œ» e œ» : 1.3SLPM(» ) ü» : 50kPa( d» ) : 80 /1z»» : œ, t 1 1z( y ƒ )»» t» :» ( )» yw w : 0.1ppm(450ppm» ), 30 s³, 80 j, 6 d y (gradient) :» y w w e w s³ y (»»» w w):
38 Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1 6 ( yk 99.7%,» 99.18% y )» z : œ» w yk» yw yk d : 0-1000ppm : 3A( l 6A) : 5-40 o C : 0-95% ù f j»(inch): 22(W) 19(D) 40(H) REFERENCES Baldocchi, D. D., 1997: Flux footprints within and over forest canopies. Boundary-Layer Meteorology 85(2), 273-292. Bradford, W., K. J. Davis, C. Yi, P. S. Bakwin, and C. L. Zhao, 2001: Long-term carbon dioxide fluxes from a very tall tower in a northern forest: Flux measurement methodology. Journal of Atmospheric and Oceanic Technology 18, 529-542. Coppin, P. A., M. R. Raupach, and B. J. Legg, 1986: Experiments on scalar dispersion within a model plant canopy. Part II: An elevated plane source. Boundary-Layer Meteorololgy 35, 167-191. Denmead, O. T., L. A. Harper, and R. R. Sharpe, 2000: Identifying sources and sinks of scalars in a corn canopy with inverse Lagrangian dispersion analysis I. heat. Agricultural and Forest Meteorology 104, 67-73. Finnigan, J. J., 2006: The storage term in eddy flux calculations. Agricultural and Forest Meteorology 136, 108-113. Haverd, V. R. Leuning, D. Griffith, E. van Gorsel, and M. Cuntz, 2008: The Lagrangian time scale for turbulent transport in forest canopies determined from measured fluxes and concentrations and modeled source distributions. Boundary-Layer Meteorology, in press. Hong, J., J. Kim, D. Lee, and J. Lim, 2008: Estimation of the storage and advection effects on H 2 O and CO 2 exchanges in a hilly KoFlux forest catchment. Water Resources. Research 44, W01426, doi:10.1029/2007wr006408. Katul, G., R. Oren, D. Ellsworth, C.-I. Hsieh, and N. Phillips, 1997: A Lagrangian dispersion model for predicting CO 2 sources, sinks, and fluxes in a uniform loblolly pine (Pinus taeda L.) stand. Journal of Geophysical Research 102, 9309-9321. Lee, X., 1998: On micrometeorological observations of surfaceair exchange over tall vegetation. Agricultural and Forest Meteorology 91, 39-49. Raupach, M. R., 1989: Applying Lagrangian fluid mechanics to infer scalar source distributions from concentration profiles in plant canopies. Agricultural and Forest Meteorology 47, 85-108.