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Evapotranspiration and water balance of high-elevation grassland on the Tibetan Plateau

Coners, Heinz; babel, Wolfgang; Willinghöfer, Sandra; Biermann, Tobias LU ; Köhler, Lars; Seeber, Elke; Thomas, Foken; Ma, Yaoming; Yang, Yongping and Miehe, Georg, et al. (2016) In Journal of Hydrology 533. p.557-566
Abstract
High-elevation grasslands of the Cyperaceae Kobresia pygmaea cover nearly half a million km2 on the Tibetan Plateau. As a consequence of climate change, precipitation patterns in this monsooninfluenced region may change with possible consequences for grassland productivity. Yet, not much is known about the water cycle in this second largest alpine ecosystem of the world. We measured the evapotranspiration of a high-elevation Kobresia pasture system at 4400 m a.s.l. in the south-eastern part of the plateau in two summers using three different approaches, weighable micro-lysimeters, eddy covariance measurements, and water balance modeling with the soil–plant–atmosphere transfer model SEWAB. In good agreement among the three approaches, we... (More)
High-elevation grasslands of the Cyperaceae Kobresia pygmaea cover nearly half a million km2 on the Tibetan Plateau. As a consequence of climate change, precipitation patterns in this monsooninfluenced region may change with possible consequences for grassland productivity. Yet, not much is known about the water cycle in this second largest alpine ecosystem of the world. We measured the evapotranspiration of a high-elevation Kobresia pasture system at 4400 m a.s.l. in the south-eastern part of the plateau in two summers using three different approaches, weighable micro-lysimeters, eddy covariance measurements, and water balance modeling with the soil–plant–atmosphere transfer model SEWAB. In good agreement among the three approaches, we found ET rates of 4–6 mm d-1 in moist summer periods (June–August) and 2mmd-1 in dry periods, despite the high elevation and a leaf area index of only 1. Measured ET rates were comparable to rates reported from alpine grasslands at 1500–2500 m a.s.l. in temperate mountains, and also matched ET rates of managed lowland grasslands in the temperate zone. At the study site with 430 mm annual precipitation, low summer rainfall reduced ET significantly and infiltration into the subsoil occurred only in moist periods. Our results show that the evapotranspiration of high-elevation grasslands at 4400 m can be as high as in lowland grasslands despite large elevational changes in abiotic and biotic drivers of ET, and periodic water shortage is likely to influence large parts of the Tibetan Kobresia pastures. (Less)
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Journal of Hydrology
volume
533
pages
557 - 566
publisher
Elsevier
external identifiers
  • scopus:84952836977
  • wos:000370086200046
ISSN
0022-1694
DOI
10.1016/j.jhydrol.2015.12.021
language
English
LU publication?
yes
id
f322d078-015e-45a9-9b83-402cec2c4bcb (old id 8518278)
date added to LUP
2016-01-12 12:36:57
date last changed
2017-06-25 03:07:12
@article{f322d078-015e-45a9-9b83-402cec2c4bcb,
  abstract     = {High-elevation grasslands of the Cyperaceae Kobresia pygmaea cover nearly half a million km2 on the Tibetan Plateau. As a consequence of climate change, precipitation patterns in this monsooninfluenced region may change with possible consequences for grassland productivity. Yet, not much is known about the water cycle in this second largest alpine ecosystem of the world. We measured the evapotranspiration of a high-elevation Kobresia pasture system at 4400 m a.s.l. in the south-eastern part of the plateau in two summers using three different approaches, weighable micro-lysimeters, eddy covariance measurements, and water balance modeling with the soil–plant–atmosphere transfer model SEWAB. In good agreement among the three approaches, we found ET rates of 4–6 mm d-1 in moist summer periods (June–August) and 2mmd-1 in dry periods, despite the high elevation and a leaf area index of only 1. Measured ET rates were comparable to rates reported from alpine grasslands at 1500–2500 m a.s.l. in temperate mountains, and also matched ET rates of managed lowland grasslands in the temperate zone. At the study site with 430 mm annual precipitation, low summer rainfall reduced ET significantly and infiltration into the subsoil occurred only in moist periods. Our results show that the evapotranspiration of high-elevation grasslands at 4400 m can be as high as in lowland grasslands despite large elevational changes in abiotic and biotic drivers of ET, and periodic water shortage is likely to influence large parts of the Tibetan Kobresia pastures.},
  author       = {Coners, Heinz and babel, Wolfgang and Willinghöfer, Sandra and Biermann, Tobias and Köhler, Lars and Seeber, Elke and Thomas, Foken and Ma, Yaoming and Yang, Yongping and Miehe, Georg and Leuschner, Christoph},
  issn         = {0022-1694},
  language     = {eng},
  pages        = {557--566},
  publisher    = {Elsevier},
  series       = {Journal of Hydrology},
  title        = {Evapotranspiration and water balance of high-elevation grassland on the Tibetan Plateau},
  url          = {http://dx.doi.org/10.1016/j.jhydrol.2015.12.021},
  volume       = {533},
  year         = {2016},
}