A complex network approach to study the extreme precipitation patterns
in a river basin
Abstract
The spatiotemporal patterns of precipitation are critical for
understanding the underlying mechanism of many hydrological and climate
phenomena. Over the last decade, applications of the complex network
theory as a data-driven technique has contributed significantly to study
the intricate relationship between many variable in a compact way. In
our work, we conduct a study to compare an extreme precipitation pattern
in Ganga River Basin, by constructing the networks using two nonlinear
methods - event synchronization (ES) and edit distance (ED). Event
synchronization has been frequently used to measure the synchronicity
between the climate extremes like extreme precipitation by calculating
the number of synchronized events between two events like time series.
Edit distance measures the similarity/dissimilarity between the events
by reducing the number of operations required to convert one segment to
another, that consider the events’ occurrence and amplitude. Here, we
compare the extreme precipitation patterns obtained from both network
construction methods based on different network’s characteristics. We
used degree to understand network topology and identify important nodes
in the networks. We also attempted to quantify the impact of
precipitation seasonality and topography on extreme events. The study
outcomes suggested that the degree is decreased in the southwest to the
northwest direction and the timing of peak precipitation influences it.
We also found an inverse relationship between elevation and timing of
peak precipitation exists and the lower elevation greatly influences the
connectivity of the stations. The study highlights that Edit distance
better captures the network’s topology without getting affected by
artificial boundaries.