한국농림기상학회지, 제 11권 제1호(2009) (pISSN 1229-5671, eISSN 2288-1859)
Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1, (2009), pp. 39~47
DOI: 10.5532/KJAFM.2009.11.1.039
ⓒ Author(s) 2014. CC Attribution 3.0 License.


설마천 유역의 혼효림에서 관측된 증발산의 계절변화

권효정(1), 이정훈(2), 이연길(2), 이진원(2), 정성원(2), 김 준(1)
(1)연세대학교 대기과학과/지구환경연구소, (2)유량조사사업단

(2008년 12월 19일 접수; 2009년 01월 14일 수정; 2009년 02월 06일 수락)

Seasonal Variations of Evapotranspiration Observed in a
Mixed forest in the Seolmacheon Catchment

Hyojung Kwon(1), Jung-Hoon Lee(2), Yeon-Kil Lee(2), Jin Won Lee(2),
Sung Won Jung(2), Joon Kim(1)
(1)Global Environment Lab, Dept. of Atmospheric Sciences, Yonsei University, Seoul 120-749, Korea
(2)Hydrological Survey Center, 301 KINTEX Zone, Daehwa-Dong, Ilsanseo-Gu,
Goyang-Si, Gyeonggi-Do, 411-806, Korea

(Received December 19, 2008; Revised January 14, 2009; Accepted February 06, 2009)

ABSTRACT
The importance of securing water resources and their efficient management has attracted more attention recently due to water deficit. In water budget analysis, however, evapotranspiration(λE) has been approximated as the residual in the water balance equation or estimated from empirical equations and assumptions. To minimize the uncertainties in these estimates, it is necessary to directly measure λE. In this study, using the eddy covariance technique, we have measured λE in a mixed forest in the Seolmacheon catchment in Korea from September 2007 to December 2008. During the growing season(May-July), λE in this mixed forest averaged about 2.2 mm d-1, whereas it was on average 0.5 mm d-1 during the non-growing season in winter. The annual total λE in 2008 was 581 mm y−1, which is about 1/3 of the annual precipitation of 1997 mm. Despite the differences in the amount and frequency of precipitation, the accumulated λE during the overlapping period(i.e., September to December) for 2007 and 2008 was both ~110 mm, showing virtually no difference. The omega factor, which is a measure of decoupling between forest and the atmosphere, was on average 0.5, indicating that the contributions of equilibrium λE and imposed λE to the total λE were about the same. The results suggest that λE in this mixed forest was controlled by various factors such as net radiation, vapor pressure deficit, and canopy conductance. In this study, based on the direct measurements of λE, we have quantified the relative contribution of λE in the water balance of a mixed forest in the Seolmacheon catchment. In combination with runoff data, the information on λE would greatly enhance the reliability of water budget analysis in this catchment.

Keyword: Water budget, Evapotranspiration, Seasonal variation, Seolmacheon catchment, Omega factor

MAIN

적요

물 부족으로 인해 수자원의 확보와 효율적인 관리의 중요성이 커지고 있음에도 불구하고, 물 수지 분석에서 증발산은 다른 성분에 비해 직접 관측이 어려워 물수지 방정식으로부터 어림되거나 단순한 가정이나 경험식으로부터 추정된다. 그러나 이러한 방법들은 오차가 커서 증발산의 신뢰도를 높이려면 직접 관측이 필요하다. 이 연구에서는 설마천 유역의 혼효림의 증발산을 정량화하기위해 2007년 9월부터 2008년 12월까지 에디 공분산 방법을 사용하여 증발산을 직접 측정하였다. 혼효림의 증발산은 성장기(5-7월)에는 평균 2.2mm d−1, 비성장기인 겨울에는 0.5mm d−1였다. 2008년 한 해동안의 총 증발산량은 581mm y−1로 연 강수량(1997mm)의 약 1/3을 차지하였다. 2007년과 2008년에 관측이 겹치는 기간(9-12월)동안 적산된 증발산 총량은 2008년 가을의 강수량과 강수빈도가 2007년의 같은 기간에 비해 적었음에도 불구하고 두기간 모두~110mm로 다르지 않았다. 산림과 대기간의 분리(decoupling) 정도를 나타내는 오메가 인자는 평균 0.5로서 평형증발산과 부과증발산이 전체 증발산에 기여하는 정도가 크게 다르지 않았다. 이는 증발산이 순복사, 포차, 기공전도도 등에 의해 골고루 영향을 받고 있음을 의미한다. 본 연구에서는 실측에 근거한 증발산 자료를 토대로 설마천 유역의 혼효림에서 증발산이 물수지에서 차지하는 기여도를 조사하였고, 향후 유출량과 함께 사용될때 설마천 산림유역의 물수지 분석의 신뢰도을 향상시킬 것으로 기대된다.

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