hydrobricks v0.6.0

Breaking changes Many changes in the Forcing class: load_from_csv() was renamed to load_station_data_from_csv(). define_spatialization() was renamed to spatialize_from_station_data() and is only meant for spatialization from station data. correct_station_data() was added and is to be used for applying a correction factor, for example. spatialize_from_gridded_data() was added to load data from gridded netCDF files. compute_pet() was added and uses the pyet package. The operations are not performed immediately, but only applied when apply_operations() is called, which is done automatically before the model run or before saving the forcing data to a netcdf file. The Catchment class is now part of the main module. Added Adding the spatialization from gridded data with spatialize_from_gridded_data(). Adding PET computation using the pyet library. New function: compute_pet(). The forcing data can now be loaded from the dumped netCDF file with load_from(). Changed Refactoring of the Forcing and TimeSeries classes to separate 1D and 2D data. Enums are used to specify the Forcing variables. The Catchment class is now part of the main module. The Catchment class can generate a geotiff of the hydro unit ids with save_unit_ids_raster() Fixed Fixing issue in elevation bands creation

hydrobricks v0.6.1

Fixed Fixing an issue with the data container shape when using the spatialization from gridded data

hydrobricks v0.6.2

Breaking changes The csv files defining the hydro units (e.g., elevation bands) properties have now to include the units of the values (e.g., m for elevation) below the column title. Added Adding the computation of the slope and aspect from the DEM. Transferring slope and aspect values to the hydrological model (e.g., for Socont quick discharge using the unit slope). Any hydro unit property can now be extracted from data and provided to the hydrological model (flexible generic approach). Adding the computation of the mean latitude and longitude for each hydro unit and allow using it for the PET computation. Adding an extraction of the forcing using a faster weighted approach. Addition of an example script for the catchment data preparation. Allow loading unit ids from raster. Adding a hydro unit discretization by elevation and aspect (separately or combined; with an example script). Changed Refactoring catchment attributes parsing. The csv files defining the hydro units (e.g., elevation bands) properties have now to include the units of the values (e.g., m for elevation) below the column title. Fixed Socont quick discharge has been fixed

Mapping and Analyzing the Evolution of the Butangbunasi Landslide Using Landsat Time Series with Respect to Heavy Rainfall Events during Typhoons

Large rainfall-induced landslides are among the most dangerous natural hazards in Taiwan, posing a risk for people and infrastructure. Thus, better knowledge about the evolution of landslides and their impact on the downstream area is of high importance for disaster mitigation. The aim of this study is twofold: (1) to semi-automatically map the evolution of the Butangbunasi landslide in south-central Taiwan using satellite remote sensing data, and (2) to investigate the potential correlation between changes in landslide area and heavy rainfall during typhoon events. Landslide area, as well as temporary landslide-dammed lakes, were semi-automatically identified using object-based image analysis (OBIA), based on 20 Landsat images from 1984 to 2018. Hourly rainfall data from the Taiwan Central Weather Bureau (CWB) was complemented with rainfall data from Climate Hazards Group Infrared Precipitation with Station data (CHIRPS) to examine the potential relationship between landslide area changes and rainfall as a triggering factor. The OBIA mapping results revealed that the most significant landslide extension happened after typhoon Morakot in 2009. We found a moderate positive relationship between the landslide area change and the duration of the heavy rainfall event, whereas daily precipitation, cumulative rainfall and mean intensity did not present strong significant correlations

Carbon footprint and reduction initiatives in a French geosciences laboratory

International audienceThe impact of our productivist societies on our environment is now clearly demonstrated. It is illustrated in particular by the alteration of biogeochemical flows, the erosion of biodiversity, the chemical pollution of environments, the anthropisation of soils, the alteration of the water cycle, the acidification of the oceans and climate change.As higher education and research staff working at the interface between science and society, we are aware of the need for an environmental transition that can only be achieved by reducing our greenhouse gas emissions and our environmental impact. We do not believe that the content of our research justifies any form of exemption and are aware of the benefits of being exemplary. As a research lab, we are committed to participating in limiting the increase in the Earth's average temperature, ideally targeted at less than 1.5°C compared to the pre-industrial period. This objective requires achieving carbon neutrality by 2050.From 2021 the Sustainable Development & Social Responsibility working group of the research laboratory “Géosciences Rennes” has been created (i) to determine the C footprint by using GES1.5 (Research Consortium labo1.5), (ii) to communicate and raising staff awareness of the climate emergency, (iii) to propose indicators for reducing the carbon footprint, (iv) to convey a message to the supervisory authorities to work on the various reduction items. The calculated C footprint includes heating of buildings, electricity, purchase of goods and services, scientific missions and commutes. Between 2019 and 2021, the C footprint was 879, 520 and 708 T CO2eq, which corresponds to 5.8, 3.6 and 5.1 T CO2eq/person. The purchase of goods and services was the main item, representing 48 ± 8 % (mean ± SD) of the C footprint. Scientific missions represented 14 ± 9 % of the C footprint. Sanitary restrictions due to the covid pandemy induced a drastic decrease of the C footprint of scientific missions from 220 T CO2eq in 2019 to 43 T CO2eq in 2020. Thanks to the GES1.5 toolkit, it is possible to identify the main emission items for a given laboratory and to design and quantify specific actions to collectively reduce the C footprint. These data were the corner stone of collaborative workshops to invent our low-carbon laboratory. This presentation will feature the data and the process of collective decision in “Géosciences Rennes” laboratory. These results highlight that achieving the European Union targets will require a rethinking of the way we do science

Southwestward tilting of the Ordos Loess Plateau, central China: topographic response to India-Asia convergence deduced from drainage systems

International audienceThe Ordos Loess Plateau with its iconic fluvial incision pattern represents an uplifted but internally stable plateau crustal block on the eastern fringe of the Tibetan Plateau. The Ordos Loess Plateau deeply incised river landscapes and hence its inaccessibility helped to protect ancient China from invading nomads from the north. The Ordos Block is internally free of seismicity but its boundaries feature severe high-magnitude earthquakes. Due to the ongoing India-Asia convergence, the northeastward expansion of the Tibetan Plateau leading to the eastward lateral extrusion of fault-bounded blocks. The Ordos Loess Plateau is part of one of these blocks and is still affected by lateral eastward motion along crustal scale faults and large surface uplift from Late Miocene to present. In this study, we investigated the effect of fault activity on the morphological evolution of the Ordos Loess Plateau. To quantify the effect of uplift gradients on the drainage systems, we investigated topographic patterns and landform metrics through field surveys and topographic analysis based on digital elevation models. Field surveys show that the southern boundary of the Ordos Loess Plateau to the Weihe Graben is still tectonically active (evidence for faulting in quaternary sediments). We found that the drainage is consistently directed towards the Weihe Graben in the southeast. Fluvial channels are in a state of morphological disequilibrium, with steep channel segments towards the Weihe Graben and meandering low gradient rivers in the central Ordos Loess Plateau. Over substantial portions, the shape of the longitudinal channel profile in the Ordos Loess Plateau is straight and deviates from usual graded longitudinal channel profiles. We further found that the degree of erosion and plateau incision is pronounced in the eastern part of the Ordos Loess Plateau, while the southwestern part is less incised. The drainage network indicated that the drainage basins are tilted toward the Liupanshan Mountains overthrust in the southwest. We conclude that the far-field influence of the Cenozoic uplift of the Tibetan Plateau activated the southwestern and southern boundary faults around the Ordos Loess Plateau. The drainage systems reorganized to a principal southern flow direction and thereby progressively incised in the Ordos Loess Plateau, causing severe soil erosion

Quantification of the damming and sediment trapping capacity of landslides and their dammed lakes: the example of the Hintersee landslide dam

International audiencePerennial landslide dams interrupt the sediment connectivity of rivers. Although most landslide dams do not persist for more than a few days, those that do can exhibit significant sediment trapping capacity. While water can pass through or over the dam, the sediment load is trapped upstream of the dam until the dam breaks or gradually erodes, or is completely filled with deposits. The volume of sediment stored in this way can reach up to three times the volume of impounded water, as we find by back-analyzing the lake Hintersee in southeastern Germany. In this work, we reconstruct the pre-landslide topography using Petrel and then use the Gerris shallow-water flow solver with a Voellmy rheology to back-analyze this landslide-dammed lake in the Bavarian Alps. We test several landslide release scenarios and different landslide rheologies to obtain the best-fitting reconstruction of the dam topography. We then fill the landslide dam with water and sediment using simple slope algorithms and validate the results against the current topography. Finally, we compare the landslide deposit thicknesses, water depths, and trapped sediment thicknesses of our different scenarios in order to provide new insight into the damming and sediment trapping capacity of landslides