TY - JOUR
T1 - Year-to-year differences in evapotranspiration from understory vegetation and whole ecosystem in an eastern Siberian larch forest
AU - Iida, Shinichi
AU - Ohta, Takeshi
AU - Matsumoto, Kazuho
AU - Nakai, Taro
AU - Kononov, Alexander V.
AU - Maximov, Trofim C.
AU - van der Molen, Michiel K.
AU - Dolman, Albertus J.
AU - Yabuki, Hironori
PY - 2016/1/1
Y1 - 2016/1/1
N2 - We measured the evapotranspiration from the understory vegetation and the whole ecosystem of a Siberian larch forest on the forest floor and above the forest canopy, respectively, using the eddy-covariance method, and obtained the year-to-year difference in evapotranspiration during the early (from 1st to 10th), middle(11th to 20th) and late (21th to the end) periods of month. The year-to-year differences in evapotranspiration from whole ecosystem and understory vegetation were in the range from -11.0 mm to 9.5 mm and from -2.4 mm to 4.7 mm, respectively. These values explained from 20% to 30% of monthly mean evapotranspiration, and thus significant differences were found in this site. To clarify the factor controlling the year-to-year difference in evapotranspiration, we analyzed the relationships among the year-to-year differences in evapotranspiration, radiative and advective terms of Penman–Monteith equation. As a result, due to the small value of decoupling factor of this forest, the most important factor was the year-to-year difference in the advective term. We found that the difference in vapor pressure deficit resulting in the change of the surface conductance was important for year-to-year difference in the advective term in this site.
AB - We measured the evapotranspiration from the understory vegetation and the whole ecosystem of a Siberian larch forest on the forest floor and above the forest canopy, respectively, using the eddy-covariance method, and obtained the year-to-year difference in evapotranspiration during the early (from 1st to 10th), middle(11th to 20th) and late (21th to the end) periods of month. The year-to-year differences in evapotranspiration from whole ecosystem and understory vegetation were in the range from -11.0 mm to 9.5 mm and from -2.4 mm to 4.7 mm, respectively. These values explained from 20% to 30% of monthly mean evapotranspiration, and thus significant differences were found in this site. To clarify the factor controlling the year-to-year difference in evapotranspiration, we analyzed the relationships among the year-to-year differences in evapotranspiration, radiative and advective terms of Penman–Monteith equation. As a result, due to the small value of decoupling factor of this forest, the most important factor was the year-to-year difference in the advective term. We found that the difference in vapor pressure deficit resulting in the change of the surface conductance was important for year-to-year difference in the advective term in this site.
U2 - 10.4145/jahs.45.109
DO - 10.4145/jahs.45.109
M3 - Article
SN - 1342-9612
VL - 45
SP - 109
EP - 121
JO - Journal of Japanese Association of Hydrological Sciences
JF - Journal of Japanese Association of Hydrological Sciences
IS - 4
ER -