This paper presents retrospective simulations (1963–2019) and future projections (1976–2100) of daily time series of discharge and stream temperature for 52 278 reaches (median length of 1.3 km) over the Loire River basin (10

Stream (water) temperature (

To overcome the lack of

This paper, using outputs of the 1-D Temperature-NETwork (T-NET) physical process-based thermal model coupled with the EROS semi-distributed hydrological model, presents daily time series of

EROS is a semi-distributed hydrological model which simulates daily discharge at the outlet of 368 homogeneous (with respect to land use and geology) sub-basins for the Loire River basin (see Fig.

Synthetic diagram showing the methodology of retrospective simulations and projections of daily

EROS had been calibrated over 1974–2018 to maximize the number of discharge near-natural observations, with 1971–1974 used for the warm-up. The calibration optimized all unknown parameters (soil capacity, recession times, and propagation times) through maximizing the Nash–Sutcliffe efficiency (NSE) criterion on the square root of discharge and minimizing the overall bias

For future projections of daily

All three selected future climate models (GCMs–RCMs) include RCP 4.5 and 8.5, which are intermediate and extreme scenarios corresponding to a plausible representation of the future behavior of human societies. The CNRM-CM5-LR–ALADIN63 model also includes RCP 2.6. Therefore, the projections are conducted under seven projections in total. For each GCM–RCM, two periods are considered: (1) the period with GCMs forced by historical concentrations in greenhouse gases between 1976 and 2005, and (2) the projection part using RCPs as forcings, which extends from 2005 to 2100 (see Table

GCMs, RCMs, and RCPs used in the current study. More information can be found at

Daily

To assess future projections of

Trends in

Summer

Projections underestimate summer

Map of relative biases between summer

In the southern (L'Allier at Monistrol-d'Allier) and northern parts (La Loire at Montjean) of the basin, summer

Changes in summer

Under RCP 8.5, the annual regime of projected

To estimate daily

To compute the six heat fluxes and the water travel time for each reach,

Unlike EROS, T-NET does not have any free parameters, and hence it is not calibrated. A validation was already done by

Observed and simulated daily

Simulated daily

Time series of summer

Figure

The maximum observed daily

For future projections of daily

An increase in

Spatial variability of average summer

There is a slight overestimation of

Map of summer

Time series of all reaches under all GCMs–RCMs show a consistent increase in summer

Figure

Daily

This data paper presented and described daily

Daily

The potential applications of the proposed dataset over the past and future are manifold. This can be employed to understand spatio-temporal variability in

The supplement related to this article is available online at:

HS developed the dataset and prepared the paper. DT ran the EROS model and provided discharge data for both the past and future. All co-authors contributed to the paper.

The contact author has declared that none of the authors has any competing interests.

Publisher’s note: Copernicus Publications remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

The authors would like to thank Météo-France for providing the Safran reanalysis data.

This work was performed in the course of a doctoral project at the University of Tours, funded by the European Regional Development Fund (Fonds Européen de développement Régional-FEDER), POI FEDER Loire (grant no. 2017-EX001784), Le plan Loire grandeur nature, AELB (Agence de l’eau Loire-Bretagne), INRAE (Institut National de Recherche pour l’Agriculture, l’alimentation et l’Environnement), and EDF (Hynes team).

This paper was edited by Giuseppe M. R. Manzella and reviewed by Vadim Grigoriev and two anonymous referees.