Version 1.5 – Updated in February 2025
Citation: If you use this dataset, please cite the following data description paper:
Helgason, H. B. and Nijssen, B.: LamaH-Ice: LArge-SaMple DAta for Hydrology and Environmental Sciences for Iceland, Earth System Science Data, 16, 2741–2771, https://doi.org/10.5194/ESSD-16-2741-2024, 2024.

Key Updates in Version 1.5.
This update extends the streamflow and meteorological time series in LamaH-Ice:
- Streamflow series from operational gauges now extend to 2024-09-30 or 2023-09-30.
- For select gauges (IDs: 8, 36, 66, 98), streamflow data has also been extended further back in time.
- Hydrological signatures have been updated accordingly.
- ERA5-Land meteorological series in LamaH-Ice have been extended to 2024-09-30 for basin delineation A. These are now sourced from the LamaH-Ice Caravan extension.
- Hourly series in the LamaH-Ice hourly dataset were not updated.

Key Updates in the LamaH-Ice Caravan Extension:
- Penman-Monteith PET has been added.
- All climate indices influenced by PET have been recomputed using the new Penman-Monteith time series.
- The ERA5-Land potential evaporation remains available, along with the old indices, but has been renamed for clarity:
- New time series names: "potential_evaporation_sum_ERA5_LAND", "potential_evaporation_sum_FAO_PENMAN_MONTEITH"
- Updated climate indices naming convention: Suffix _ERA5_LAND for indices using ERA5-Land PET, Suffix _FAO_PM for indices using FAO Penman-Monteith PET.
- Streamflow observations have been added for two additional gauges (IDs: 1010, 9900).

Original dataset description:
LamaH-Ice (LArge-SaMple DAta for Hydrology and Environmental Sciences for Iceland) is a large-sample hydro-meteorological dataset for Iceland. The dataset includes daily and hourly hydro-meteorological timeseries, including observed streamflow, and catchment characteristics for 107 river basins in Iceland. The catchment characteristics describe the topographic, hydroclimatic, land cover, vegetation, soils, geological and glaciological attributes of the river catchments, as well as the human influence on streamflow in the catchments. LamaH-Ice conforms to the structure of existing large-sample hydrology datasets and includes most variables offered in these datasets, as well as additional information relevant to cold-region hydrology, e.g., timeseries of snow cover, glacier mass balance and albedo. A large majority of the watersheds in LamaH-Ice are not subject to human activities, such as diversions and flow regulations. The dataset is described in detail in a paper in the journal "Earth System Science Data" (ESSD - https://doi.org/10.5194/essd-2023-349) The code used to assemble the dataset is available in folder "F_appendix" in the dataset as well as on GitHub (https://github.com/hhelgason/LamaH-Ice)

We offer two downloadable files for the LamaH-Ice dataset: 1) Hydrometeorological time series with both daily and hourly resolutions (30 GB after decompression) and 2) Hydrometeorological time series with daily resolution only (2 GB). Other than the temporal resolution, there are no differences between the two downloadable files. This HydroShare resource also hosts the "LamaH-Ice Caravan extension" (1 GB), which complements the "Caravan - A global community dataset for large-sample hydrology" Caravan dataset (Kratzert et al., 2023). The data is formatted in the same manner as the data currently existing in Caravan. To process the Caravan extension, the following guide was used: https://github.com/kratzert/Caravan/wiki/Extending-Caravan-with-new-basins. Some features, e.g. hourly atmospheric and streamflow series, glacier mass balance and MODIS timeseries data are thus only available in the LamaH-Ice dataset.

Data disclaimer: The Icelandic Meteorological Office (IMO) and the National Power Company of Iceland (NPC) own the data from most streamflow gauges in the dataset. The streamflow data is published on Hydroshare with permission of all data owners. Neither we nor the provider of the streamflow dataset can be liable for the data provided. The IMO and the NPC reserve the rights to retrospectively check and update the streamflow timeseries at any time, and these changes will not be reflected in this published dataset. If up-to-date data is needed, users are encouraged to contact the IMO and the NPC.

License: The streamflow data is subject to the CC BY-NC 4.0 (creativecommons.org/licenses/by-nc/4.0/) The streamflow data cannot be used for commercial purposes. All data except for the streamflow measurements are subject to the CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/) Users can share and adapt the dataset only if appropriate credit is given (the ESSD data description paper is cited, the version of the dataset and all data sources are listed which are declared in the folder "Info") and any changes are clearly indicated, and a link to the original license is provided.