- G. Laaha (6)
- H.A.J. Lanen van (3)
- H.A.J. Lanen Van (1)
- C. Lang Delus (1)
- A.F. Loon Van (2)
- A.F. Loon van (1)
- T. Nester (1)
- J. Parajka (1)
- S.W. Ploum (1)
- M. Rogger (1)
- E. Sauquet (3)
- L.M. Tallaksen (3)
- R. Woods (2)
- R.A. Woods (1)
- A. Young (1)
Hydrological drought types in cold climates : Quantitative analysis of causing factors and qualitative survey of impacts
Loon, A.F. Van; Ploum, S.W. ; Parajka, J. ; Fleig, A.K. ; Garnier, E. ; Laaha, G. ; Lanen, H.A.J. Van - \ 2015
Hydrology and Earth System Sciences 19 (2015)4. - ISSN 1027-5606 - p. 1993 - 2016.
For drought management and prediction, knowledge of causing factors and socio-economic impacts of hydrological droughts is crucial. Propagation of meteorological conditions in the hydrological cycle results in different hydrological drought types that require separate analysis. In addition to the existing hydrological drought typology, we here define two new drought types related to snow and ice. A snowmelt drought is a deficiency in the snowmelt discharge peak in spring in snow-influenced basins and a glaciermelt drought is a deficiency in the glaciermelt discharge peak in summer in glacierised basins. In 21 catchments in Austria and Norway we studied the meteorological conditions in the seasons preceding and at the time of snowmelt and glaciermelt drought events. Snowmelt droughts in Norway were mainly controlled by below-average winter precipitation, while in Austria both temperature and precipitation played a role. For glaciermelt droughts, the effect of below-average summer air temperature was dominant, both in Austria and Norway. Subsequently, we investigated the impacts of temperature-related drought types (i.e. snowmelt and glaciermelt drought, but also cold and warm snow season drought and rain-to-snow-season drought). In historical archives and drought databases for the US and Europe many impacts were found that can be attributed to these temperature-related hydrological drought types, mainly in the agriculture and electricity production (hydropower) sectors. However, drawing conclusions on the frequency of occurrence of different drought types from reported impacts is difficult, mainly because of reporting biases and the inevitably limited spatial and temporal scales of the information. Finally, this study shows that complete integration of quantitative analysis of causing factors and qualitative analysis of impacts of temperature-related droughts is not yet possible. Analysis of selected events, however, points out that it can be a promising research area if more data on drought impacts become available.
Hydrological drought severity explained by climate and catchment characteristics
Loon, A.F. Van; Laaha, G. - \ 2015
Journal of Hydrology 526 (2015). - ISSN 0022-1694 - p. 3 - 14.
Catchment characteristics - Climate - Drought deficit - Drought duration - Hydrological drought severity - Storage
Impacts of a drought are generally dependent on the severity of the hydrological drought event, which can be expressed by streamflow drought duration or deficit volume. For prediction and the selection of drought sensitive regions, it is crucial to know how streamflow drought severity relates to climate and catchment characteristics. In this study we investigated controls on drought severity based on a comprehensive Austrian dataset consisting of 44 catchments with long time series of hydrometeorological data (on average around 50. year) and information on a large number of physiographic catchment characteristics. Drought analysis was performed with the variable threshold level method and various statistical tools were applied, i.e. bivariate correlation analysis, heatmaps, linear models based on multiple regression, varying slope models, and automatic stepwise regression. Results indicate that streamflow drought duration is primarily controlled by storage, quantified by the Base Flow Index or by a combination of catchment characteristics related to catchment storage and release, e.g. geology and land use. Additionally, the duration of dry spells in precipitation is important for streamflow drought duration. Hydrological drought deficit, however, is governed by average catchment wetness (represented by mean annual precipitation) and elevation (reflecting seasonal storage in the snow pack and glaciers). Our conclusion is that both drought duration and deficit are governed by a combination of climate and catchment control, but not in a similar way. Besides meteorological forcing, storage is important; storage in soils, aquifers, lakes, etc. influences drought duration and seasonal storage in snow and glaciers influences drought deficit. Consequently, the spatial variation of hydrological drought severity is highly dependent on terrestrial hydrological processes.
|Regional assessment of low flow processes and prediction methods across European regimes
Laaha, G. ; Loon, A.F. van; Lang Delus, C. ; Koffler, D. - \ 2014
|Prediction of low flows in ungauged basins
Laaha, G. ; Hisdal, H. ; Kroll, C.N. ; Lanen, H.A.J. van; Nester, T. ; Rogger, M. ; Sauquet, E. ; Tallaksen, L.M. ; Woods, R.A. ; Young, A. - \ 2013
In: Run-off Prediction in Ungauged Basins, Synthesis across Processes, Places and Scales / Bloschl, G., Wagener, S., Viglione, Th.M., Savenije, H., Cambridge University Press - ISBN 9781107028180 - p. 163 - 188.
UNESCO-FRIENDS contribution to the PUB Benchmark Assessment Report on low flow estimation
Laaha, G. ; Sauquet, E. ; Hisdal, H. ; Kroll, C.N. ; Lanen, H.A.J. van; Tallaksen, L.M. ; Woods, R. - \ 2011
|Friend's contribution to the PUB Benchmark Assessment Report on low flow estimation
Laaha, G. ; Sauquet, E. ; Hisdal, H. ; Kroll, C.N. ; Lanen, H.A.J. van; Tallaksen, L.M. ; Woods, R. - \ 2010
In: Global Change: Facing Risks and Threats to Water Resources Centre for Ecology and Hydrology, Wallingford, Oxfordshire, OX10 8BB, UK : IAHS - ISBN 9781907161131 - p. 54 - 60.