Evaporation from an eastern Siberian larch forest

• Published in: Agricultural and forest meteorology Vol. 85; no. 3; pp. 135 - 147
• Main Authors: Kelliher, F.M., Hollinger, D.Y., Schulze, E.-D., Vygodskaya, N.N., Byers, J.N., Hunt, J.E., McSeveny, T.M., Milukova, I., Sogatchev, A., Varlargin, A., Ziegler, W., Arneth, A., Bauer, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-1997
• Subjects: Larch; Larix gmelinii; Total forest evaporation; Understorey evaporation; Yakutsk Region, Russian Federation; Larix gmelinii; Total forest evaporation; Understorey evaporation; Larch
• ISSN: 0168-1923; 1873-2240
• DOI: 10.1016/S0168-1923(96)02424-0

Total forest evaporation (
λE), understorey evaporation, and environmental variables were measured on nine summer days under different weather conditions in a 130-year-old stand of
Larix gmelinii (Rupr.) Rupr. trees located 160 km south of Yakutsk in eastern Siberia, Russia (61°N, 128°E, 300m above sea-level (a.s.l.)). Tree and broad-leaved understorey vegetation one-sided leaf area indices were 1.5 and 1.0, respectively. Agreement of
λE and sensible heat flux (
H), both measured by eddy covariance, and the available energy (
R
a) was generally good: (
H +
λE) = 0.83
R
a + 9 W m
−2 with
r
2 = 0.92 for 364 half-hour periods and the mean ± 95% confidence limit was 129 ± 17 for (
H +
λE) and 144 ± 19 for
R
a. Daily
E was 1.6–2.2 min, less than half of the potential evaporation rate and accounting for 31–50% of
R
a, with the lowest percentage on clear days. A perusal of the sparse literature revealed that average daily
E of boreal coniferous forest during the tree growing season (1.9 mm day
−1 for this study) is relatively conservative, suggesting that low evaporation rates are a feature of this biome's energy balance. Using the Penman-Monteith equation, the maximum bulk-surface conductance (
G
smax) was 10 mm s
−1.
E and
G
s were regulated by irradiance, air saturation deficit, and surface soil water content during a week-long dry period following 20 mm rainfall. From lysimeter measurements, 50% of
E emanated from the understorey at a rate proportional to
R
a. Based on the measurements and published climatological data, including average annual precipitation equal to 213 mm, water balance calculations indicated growing season forest
E equal to 169 mm, the occurrence of a late summer-autumn soil water deficit, and annual runoff of 44 mm by snowmelt.