 |
| Titel |
Investigating changes in the land water balance based on the Budyko phase space |
| VerfasserIn |
Peter Greve, Boris Orlowsky, Sonia I. Seneviratne |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078756
|
|
|
|
|
|
| Zusammenfassung |
| Changes in the climatological land water balance affect a wide range of socio-economical
issues. Thus, the identification of regions undergoing a substantial drying or wetting is of
major interest in climate science. Despite the simplicity of the underlying water balance
equation, its individual variables are of complex nature. Global estimates, either derived from
observations or from models, of precipitation (P ) and especially evapotranspiration (ET) are
characterized by high uncertainties. This leads to inconsistent results in determining changes
in the land water balance and its components.
We use the Budyko phase space with the ratios ET-P and Ep-P (with Ep being the
potential evaporation) as proxies for the land water balance and climate conditions. Using
many available global data sets for ET and P and different methods to determine Ep
creates more than 700 possible combinations for ET-P in conjunction with Ep-P
within the period from 1950 to 2005 and more than 2000 combinations within a
shorter period covering the satellite era since the 1980s. To assess the realism of
the individual combinations, we compare them against the Budyko curve, which
is a well established empirically-based relationship between ET-P and Ep-P .
We find that uncertainties are primarily induced by the ET data sets. In particular,
reanalysis and CMIP5 data sets are characterized by low realism. To analyse decadal
changes, only those combinations performing well within the Budyko framework are
considered. Shifts towards drier or wetter conditions are identified in the Budyko
phase space. When the majority of combinations reveals a consistent shift towards
drier/wetter conditions, we interpret this as a significant change in the decadal land water
balance.
This comprehensive approach is suitable to identify regional drying or wetting
trends. Further, we are able to verify results of previous studies, using less data sets
and only considering precipitation or temperature in their analysis. First results
indicate consistent findings with previous studies regarding long-term changes in the
water balance, but also some distinct features, e.g. in the Mediterranean region. |
|
|
|
|
|
|