Spatial classification of monthly to pluri-annual precipitation, temperature and discharge variability in France, 1968-2008, using Wavelet Transform and Image Euclidean Distance Clustering
Abstract
Several studies have shown that hydrological variability results from the action of atmospheric circulation and watershed dynamics. In France, it has been shown that those factors vary spatially thus several spatial classifications of hydrological variables have been established. Precipitation, temperature and discharge classifications offer an input (precipitation, temperature) to output (discharge) comparison allowing inferring areas where the watershed dynamics have the most profound impact. However most studies make the assumption that climate drivers and watershed dynamics are time scale independent i.e. that spatial classifications of hydrological variables will be the same whatever the time scale considered. This is in contrast with recent results that show time scale dependence in climate drivers as well as watershed dynamics especially within the infiltration-groundwater system. This study aims at establishing the spatial classifications of 152 stations monthly time series (1968-2008) for precipitation, temperature and discharge. For each variable, the 152 stations continuous wavelet transforms are compared and clustered. The continuous wavelet transform of a time series is a map from the time domain to the time-scale domain allowing characterization of a time series scales of variability as well as when those occur. In order to compute similarity between the continuous wavelet transform of each station, we use a generalization of the Euclidean Distance known as Image Euclidean Distance. The main question of this study is to see whether hydrological stations show different time scales of variability and if those stations can be clustered into spatially homogeneous groups.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H33O2289F
- Keywords:
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- 1804 Catchment;
- HYDROLOGYDE: 1830 Groundwater/surface water interaction;
- HYDROLOGYDE: 1833 Hydroclimatology;
- HYDROLOGYDE: 1839 Hydrologic scaling;
- HYDROLOGY