Be Kind, Rewind!
Flood risk assessment relies on hydrometric stations (sometimes called streamgages) that monitor river discharge, i.e. the amount of water flowing in rivers every hour or day.
Floods and Heavy Precipitation in the World
Observed data are essential to understand, quantify and predict the risk posed by extreme climatic events. In the case of floods or heavy precipitation, such data take the form of long series measured at stream gauging or weather stations.
Hydrological Soundscapes
The seasonality of flows in a river is an important part of its identity. Many studies start by displaying a chart similar to the one below to identify high-flow and low-flow seasons at a glance.
Hydrology basics, episode 2: the rhythm of flood occurrences
“This was a 100-year event”. This type of sentence is often heard in the news after a flood or a storm hits somewhere, as it does a good job at carrying the rarity of what happened.
L'eau des rivières et le changement climatique
Avant de s’écouler dans la rivière, l’eau suit un long périple au sein de la surface de collecte des eaux appelée bassin versant (en rouge ci-dessous).
A postcard from Antarctica
Some time ago we’ve been lucky enough to receive the postcard below from the Mc Murdo Dry Valleys, in Antarctica (thank you so much Kaelin!
Revealing Hidden Climate Indices
In a previous post, we illustrated a widely used method called principal component analysis (PCA). This method can be used as an exploratory tool to summarise a dataset made of hundreds or thousands of time series into just a few ‘summary’ time series called principal components.
Finding hidden patterns in the data using principal components analysis
In hydrology, it is frequent to analyse long time series coming from many sites. The figure below shows monthly streamflows at 207 sites in France for the period 1969-2014.
An interactive app to explore world floods
The Global Streamflow Indices and Metadata Archive describes hydrological regimes all over the World. A subset of around 2000 stations over the period 1903-2016 is used in the HEGS project to study floods at the global scale.
Folding and bending data
In the fun with dendrograms post, a linear dendrogram is gradually bent into a full circle. This transformation isn’t specific to dendrograms and can be applied to any dataset.
About the logo
The globXblog logo is a colourful doughnut that mimics an equaliser, referring to the sonification and visualisation part of the blog. In its core, a stormy icon represents the hydrological part of the blog.
Hydrology basics, episode 1: streamflow, precipitation and evapotranspiration
How does water end up flowing in rivers? As schematized below, it is the result of processes that have taken place in the river basin, also known as a catchment and delineated by a red line in the figure.