Title: River temperature response to atmospheric heatwaves in the European Alps

Contact: Amber van Hamel, amber.vanhamel@slf.ch

Description: 

This dataset accompanies the paper "River temperature response to atmospheric heatwaves is modulated by discharge and meltwater" by Van Hamel et al. (2026) published in Communications Earth & Environment (DOI: 10.1038/s43247-026-03269-6).

Structure of this folder:

- Subfolder 1: 'Shapefiles_geospatial'
	- Catchments_275.shp : Shapefile with the 275 catchments in Switzerland and Austria, including the station ID and geometry.
	- Stations_275.shp : Shapefile with the 275 measurement stations in Switzerland and Austria, including the station ID and geometry.
	- Catchments_characteristics_275st.csv : An overview of some catchment characteristics per catchment.

- Subfolder 2: 'Variables_annual_regimes'
	- AT_annual_regime_275st.csv : Annual regime of air temperature (AT) per catchment, in degrees Celsius.
	- Eva_annual_regime_275st.csv : Annual regime of actual evaporation (Eva) per catchment, in mm/d.
	- Melt_annual_regime_275st.csv : Annual regime of meltwater (Melt = snowmelt + glacial melt) per catchment, in mm/d.
	- MeltFrac_annual_regime_275st.csv : Annual regime of meltwater fraction (Melt / (Melt + P - Eva)) per catchment, no unit.
	- P_annual_regime_275st.csv : Annual regime of precipitation (P) per catchment, in mm/d.
	- PminEva_annual_regime_275st.csv : Annual regime of precipitation minus evaporation (PminEva) per catchment, in mm/d.
	- Qs_annual_regime_275st.csv : Annual regimes of catchment specific discharge (Q) per catchment, in mm/d.
	- Rad_annual_regime_275st.csv : Annual regimes of surface net solar radiation (Rad) per catchment, in J m-2.
	- RH_annual_regime_275st.csv : Annual regimes of relative humidity (RH) per catchment, in %.
	- Soil_annual_regime_275st.csv : Annual regimes of liquid volumetric soil moisture (Soil) per catchment, in m3 m-3.
	- WT_annual_regime_275st.csv : Annual regimes of river water temperature (WT) per catchment, in degrees Celcius.

- Subfolder 3: 'Variables_during_atmospheric_heatwaves'
	- All_events.csv : A detailed overview of all identified atmospheric heatwaves per catchment, including the absolute/anomaly/z-score of the different variables of interest during the time window of each atmospheric heatwave. Includes also information on the overlap of atmospheric heatwaves with riverine heatwaves.
	- WT_riverheatwave_events.csv : A detailed overview of all identified riverine heatwaves per catchment, including the absolute/anomaly/z-score of water temperature during the time window of each riverine heatwave.

- Subfolder 4: 'Variables_timeseries_zscores'
	- AT_data_5d_zscore_275st.csv : timeseries from 2011 to 2021 of the z-score of air temperature (AT) per catchment.
	- WT_data_5d_zscore_275st.csv : timeseries from 2011 to 2021 of the z-score of water temperature (WT) per catchment.
	- Melt_data_5d_zscore_275st.csv : timeseries from 2011 to 2021 of the z-score of meltwater (Melt) per catchment.
	- Q_data_5d_zscore_275st.csv : timeseries from 2011 to 2021 of the z-score of discharge (Q) per catchment. 

- Python jupyter notebook: 'Code_heatwave_analysis_regenerate_figures.ipynb'
	- This Jupyter notebook can be used, in combination with the data that is provided in the other folders, to generate the figures that we present in our manuscript and in the Supplementary information. 


Meta data per file:

Meta data for files in Subfolder 1: 'Shapefiles_geospatial'
Meta data 'Catchments_38.shp' and 'Stations_38.shp'
- "station_ID" : ID of the catchment, can be used to link to the other files
- "geometry" : geometry information in EPSG:3035 - ETRS89-extended / LAEA Europe

Meta data 'Catchments_characteristics_275st.csv'
- "wkt_geom" : geometry information in EPSG:3035 - ETRS89-extended / LAEA Europe
- "Country" : 'AU' stands for Austria, 'CH' stands for Switzerland
- "station_ID" : ID of the catchment, can be used to link to the other files
- "govnr" : the government ID number under which the catchment is known in Austria or Switzerland
- "area_calc" : calculated catchment area (km^2)
- "elev_mean" : mean catchment elevation (m.a.s.l.)
- "elev_med" : median catchment elevation (m.a.s.l.)
- "elev_ran" : elevation range within the catchment; the difference between minimum and maximum elevation (m)
- "p_as_snow_frac" : fraction of precipitation that falls as snow (-)
- "glacier_frac" : fraction of catchment area that is covered by glaciers (-)
- "Qdailymean_mmday" : mean daily specific discharge (mm d-1)
- "hydrologic_regime" : hydrologic regime based on Pardé coefficient and hierarchical clustering, either nival, mixed, or pluvial regime (-)

Meta data for all files in Subfolder 2: 'Variables_annual_regimes'
Depending on the variable in the title of the file, each file presents the annual regimes for all 275 catchments: '{variable}_annual_regime_275st.csv'
- "variable" in file name : AT = air temperature (degrees C), Eva = actual evaporation (mm d-1), Melt = snowmelt + glacial melt (mm d-1), MeltFrac = meltfraction (-), P = Precipitation (mm d-1), PminEva = precipitation - evaporation (mm d-1), Qs = area-specific discharge (mm d-1), Rad = surface net solar radiation (J m-2), RH = relative humidity (%), Soil = liquid volumetric soil moisture (m3 m-3), WT = water temperature (degrees C)
- "doy" : day of the year, starting from the 1st of January (doy = 1)
- "{station_ID}" : Every column represents one catchment. The ID of the catchment can be used to link to the other files.
Note: for more explanation about the annual regimes and the collection of the hydroclimatic variables, see 'Methods' section in our paper. 

Meta data for 'All_events.csv' in Subfolder 3: 'Variables_during_atmospheric_heatwaves' 
- "station_ID" : ID of the catchment, can be used to link to the other files
- "start" : start date of the atmospheric heatwave (DD/MM/YYYY)
- "end" : end date of the atmospheric heatwave (DD/MM/YYYY)
- "event_doy" : day of the year (doy) on which the event started
- "duration_days" : duration of the event (in days)
- "RH_during_AH_1" : 1 if the atmospheric heatwave (AH) overlaps with the riverine heatwave (RH), 0 if this is not the case
- "AHRH_start" : start date of the riverine heatwave (DD/MM/YYYY)
- "AHRH_end" : end date of the riverine heatwave (DD/MM/YYYY)
- "ATWThw_durdiff_days" : (only if "RH_during_AH_1" == 1) the duration difference (in days) between the duration of the atmospheric and the riverine heatwave
- "ATWThw_timelag_days" : (only if "RH_during_AH_1" == 1) the time difference (in days) between the start date of the atmospheric heatwave and the start date of the riverine heatwave
- "elev_mean" : mean catchment elevation (m.a.s.l.)
- "catch_area" : catchment area (km^2)
- "frac_snow" : fraction of precipitation per catchment that falls as snow (%)
- "zscore_5dmean_{variable}" : the mean 5-day z-score of the variable of interest during the event
- "anomaly_5dmean_{variable}" : the mean 5-day anomaly of the variable of interest during the event
- "absolute_5dmean_{variable}" : the mean 5-day absolute value of the variable of interest during the event
Note: for more explanation on the extraction of atmospheric and riverine heatwaves and the calculation of z-scores, see 'Methods' section in our paper. 

Meta data for WT_riverheatwave_events.csv in Subfolder 3: 'Variables_during_atmospheric_heatwaves'
- "station_ID" : ID of the catchment, can be used to link to the other files
- "start" : start date of the riverine heatwave (DD/MM/YYYY)
- "end" : end date of the riverine heatwave (DD/MM/YYYY)
- "event_doy" : day of the year (doy) on which the event started
- "duration_days" : duration of the event (in days)
- "zscore_5dmax" : maximum 5-day water temperature z-score during the event
- "zscore_5dmean" : mean 5-day water temperature z-score during the event
- "anomaly_5dmax" : maximum 5-day water temperature anomaly (in degrees Celsius) during the event
- "anomaly_5dmean" : mean 5-day water temperature anomaly (in degrees Celsius) during the event
- "absolute_5dmax" : maximum 5-day water temperature absolute value (in degrees Celsius) during the event
- "absolute_5dmean" : mean 5-day water temperature absolute value (in degrees Celsius) during the event


Meta data for all files in Subfolder 4: 'Variables_timeseries_zscores'
Depending on the variable in the title of the file, each file presents the timeseries of the z-scores for all 275 catchments: '{variable}_data_5d_zscore_275st.csv'
- "variable" in file name : AT = air temperature (degrees C), Melt = snowmelt + glacial melt (mm d-1), Q = area-specific discharge (mm d-1), WT = water temperature (degrees C)
- "datetime" : date (dd-mm-yyyy)
- "station_ID" : Every column represents one catchment. The ID of the catchment can be used to link to the other files.
Note: for more explanation on the calculation of 5-day mean z-scores, see the 'Methods' section in our paper.