חיפוש מתקדם
Ecohydrology
Yaseef, N.R., Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Yakir, D., Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Rotenberg, E., Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Schiller, G., Environmental Physics and Irrigation
Institute of Soil, Water and Environmental Science, A.R.O. Volcani Center, Bet Dagan 50250, Israel
Cohen, S., Environmental Physics and Irrigation
The distribution of precipitation inputs into different hydrological components of water-limited forest ecosystems determines water availability to trees and consequently forest productivity. We constructed a complete hydrological budget of a semi-arid pine forest (285 mm annual precipitation) by directly measuring its main components: precipitation (P), soil water content, evapotranspiration (ET, eddy covariance), tree transpiration (sap flux), soil evaporation (soil chambers), and intercepted precipitation (calculated). Our results indicated that on average for the 4-year study period, ET accounted for 94% of P, varying between 100% when P < 250 mm and 85% when P > 300 mm (with indications for losses to subsurface flow and soil moisture storage in wetter years). Direct measurements of the components of the ET flux demonstrated that both transpiration and soil evaporation were significant in this dry forest (45% and 36% of ET, respectively). Comparison between ecosystem ET (eddy covariance measurements) and the sum of its measured components showed good agreement on annual scales, but up to 30% discrepancies (in both directions) on shorter timescales. The pulsed storm pattern, characteristics of semi-arid climates, was sufficient to maintain the topsoil layer wet during the whole wet season. Only less often and intensive storms resulted in infiltration to the root zone, increasing water availability for uptake by deeper roots. Our results indicate that climate change predictions that link reduced precipitation with increased storm intensity may have a smaller effect on water availability to forest ecosystems than reduced precipitation alone, which could help forests' survival and maintain productivity even under drier conditions. Copyright © 2009 John Wiley & Sons, Ltd.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Ecohydrology of a semi-arid forest: Partitioning among water balance components and its implications for predicted precipitation changes
3
Yaseef, N.R., Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Yakir, D., Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Rotenberg, E., Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
Schiller, G., Environmental Physics and Irrigation
Institute of Soil, Water and Environmental Science, A.R.O. Volcani Center, Bet Dagan 50250, Israel
Cohen, S., Environmental Physics and Irrigation
Ecohydrology of a semi-arid forest: Partitioning among water balance components and its implications for predicted precipitation changes
The distribution of precipitation inputs into different hydrological components of water-limited forest ecosystems determines water availability to trees and consequently forest productivity. We constructed a complete hydrological budget of a semi-arid pine forest (285 mm annual precipitation) by directly measuring its main components: precipitation (P), soil water content, evapotranspiration (ET, eddy covariance), tree transpiration (sap flux), soil evaporation (soil chambers), and intercepted precipitation (calculated). Our results indicated that on average for the 4-year study period, ET accounted for 94% of P, varying between 100% when P < 250 mm and 85% when P > 300 mm (with indications for losses to subsurface flow and soil moisture storage in wetter years). Direct measurements of the components of the ET flux demonstrated that both transpiration and soil evaporation were significant in this dry forest (45% and 36% of ET, respectively). Comparison between ecosystem ET (eddy covariance measurements) and the sum of its measured components showed good agreement on annual scales, but up to 30% discrepancies (in both directions) on shorter timescales. The pulsed storm pattern, characteristics of semi-arid climates, was sufficient to maintain the topsoil layer wet during the whole wet season. Only less often and intensive storms resulted in infiltration to the root zone, increasing water availability for uptake by deeper roots. Our results indicate that climate change predictions that link reduced precipitation with increased storm intensity may have a smaller effect on water availability to forest ecosystems than reduced precipitation alone, which could help forests' survival and maintain productivity even under drier conditions. Copyright © 2009 John Wiley & Sons, Ltd.
Scientific Publication
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