Hydrological signature indicators

CHANGELOG.rst

@@ -4,7 +4,7 @@ Changelog
 
 v0.61.0 (unreleased)
 --------------------
-Contributors to this version: Pascal Bourgault (:user:`aulemahal`), Trevor James Smith (:user:`Zeitsperre`), Hui-Min Wang (:user:`Hem-W`), Éric Dupuis (:user:`coxipi`).
+Contributors to this version: Pascal Bourgault (:user:`aulemahal`), Trevor James Smith (:user:`Zeitsperre`), Hui-Min Wang (:user:`Hem-W`), Éric Dupuis (:user:`coxipi`), Ève Larose (:user:`e-larose`).
 
 New indicators and features
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -13,6 +13,7 @@ New indicators and features
 * Added two `zero_inflated` arguments to `standardized_index` and `standardized_precipitation_index` to control how zero-precipitation probabilities are handled. (:issue:`2279`, :pull:`2280`).
 * ``xclim.indices.stats.parametric_pdf`` allows to compute PDF distributions with given input parameters and values  (:pull:`2323`).
 * ``xclim.indices.standardized_precipitation_index`` and ``xclim.indices.standardized_precipitation_evapotranspiration_index`` now can accept `genextreme` and `lognorm` as inputs for `dist`. (:issue:`2326`, :pull:`2327`).
+* New hydrological indices added to ``xclim.indices._hydrology.py``. (:issue:`1624`, :pull:`2227`).
 
 Internal changes
 ^^^^^^^^^^^^^^^^
@@ -33,7 +34,7 @@ Bug fixes
 
 v0.60.0 (2026-01-23)
 --------------------
-Contributors to this version: Éric Dupuis (:user:`coxipi`), Trevor James Smith (:user:`Zeitsperre`), Juliette Lavoie (:user:`juliettelavoie`), Ève Larose (:user:`e-larose`), Faisal Mahmood (:user:`faimahsho`), David Huard (:user:`huard`), Pascal Bourgault (:user:`aulemahal`).
+Contributors to this version: Éric Dupuis (:user:`coxipi`), Trevor James Smith (:user:`Zeitsperre`), Juliette Lavoie (:user:`juliettelavoie`),  Faisal Mahmood (:user:`faimahsho`), David Huard (:user:`huard`), Pascal Bourgault (:user:`aulemahal`).
 
 Breaking changes
 ^^^^^^^^^^^^^^^^

docs/references.bib

@@ -4799,42 +4799,6 @@ @article{alonso_gonzalez_2022
   author        = {
     Esteban Alonso-Gonz\'{a}lez and Jes\'{u}s Revuelto and Steven R. Fassnacht
     and Juan {Ignacio L\'{o}pez-Moreno}
-  },
-  abstract      = {
-    The duration of the seasonal snowpack determines numerous aspects of the
-    water cycle, ecology and the economy in cold and mountainous regions, and
-    is a balance between the magnitude of accumulated snow and the rate of
-    melt. The contribution of each component has not been well quantified under
-    contrasting topography and climatological conditions although this may
-    provide useful insights into how snow cover duration could respond to
-    climate change. Here, we examined the contribution of the annual peak snow
-    water equivalent (SWE) and the seasonal melt rate to define the duration of
-    the snowpack over temperate mountains, using snow data for mountain areas
-    with different climatological characteristics across the Iberian Peninsula.
-    We used a daily snowpack database for the period 1980--2014 over Iberia to
-    derive the seasonal peak SWE, melt rate and season snow cover duration. The
-    influence of peak SWE and melt rates on seasonal snow cover duration was
-    estimated using a stepwise linear model approach. The stepwise linear
-    models showed high R-adjusted values (average R-adjusted = 0.7), without
-    any clear dependence on the elevation or geographical location. In general,
-    the peak SWE influenced the snow cover duration over all of the mountain
-    areas analysed to a greater extent than the melt rates (89.1\%, 89.2\%,
-    81.6\%, 93.2\% and 95.5\% in the areas for the Cantabrian, Central,
-    Iberian, Pyrenees and Sierra Nevada mountain ranges, respectively). At
-    these colder sites, the melt season occurs mostly in the spring and tends
-    to occur very fast. In contrast, the areas where the melt rates dominated
-    snow cover duration were located systematically at lower elevations, due to
-    the high interannual variability in the occurrence of annual peak SWE (in
-    winter or early spring), yielding highly variable melt rates. However, in
-    colder sites the melt season occurs mostly in spring and it is very fast in
-    most of the years. The results highlight the control that the seasonal
-    precipitation patterns, in combination with temperature, exert on the
-    seasonal snow cover duration by influencing the peak SWE and suggest a
-    future increased importance of melt rates as temperatures increase. Despite
-    the high climatological variability of the Iberian mountain ranges, the
-    results showed a consistent behaviour along the different mountain ranges,
-    indicating that the methods and results may be transferrable to other
-    temperate mountain areas of the world.
   }
 }
 @article{sauquet_2025,
@@ -4870,28 +4834,6 @@ @article{burn_2010
   doi           = {https://doi.org/10.1002/hyp.7625},
   url           = {https://onlinelibrary.wiley.com/doi/abs/10.1002/hyp.7625},
   eprint        = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/hyp.7625},
-  abstract      = {
-    Abstract The potential impacts of climate change can alter the risk to
-    critical infrastructure resulting from changes to the frequency and
-    magnitude of extreme events. As well, the natural environment is affected
-    by the hydrologic regime, and changes in high flows or low flows can have
-    negative impacts on ecosystems. This article examines the detection of
-    trends in extreme hydrological events, both high and low flow events, for
-    streamflow gauging stations in Canada. The trend analysis involves the
-    application of the Mann–Kendall non-parametric test. A bootstrap resampling
-    process has been used to determine the field significance of the trend
-    results. A total of 68 gauging stations having a nominal record length of
-    at least 50 years are analysed for two analysis periods of 50 and 40 years.
-    The database of Canadian rivers investigated represents a diversity of
-    hydrological conditions encompassing different extreme flow generating
-    processes and reflects a national scale analysis of trends. The results
-    reveal more trends than would be expected to occur by chance for most of
-    the measures of extreme flow characteristics. Annual and spring maximum
-    flows show decreasing trends in flow magnitude and decreasing trends in
-    event timing (earlier events). Low flow magnitudes exhibit both decreasing
-    and increasing trends. Copyright \textcopyright{} 2010 John Wiley \& Sons,
-    Ltd.
-  },
   year          = {2010}
 }
 @article{zomer_2022,
@@ -5009,3 +4951,117 @@ @article{jaffres_2021
     low-flow periods.
   }
 }
+@article{alonso_gonzalez_2022,
+  title         = {
+    Combined influence of maximum accumulation and melt rates on the duration
+    of the seasonal snowpack over temperate mountains
+  },
+  journal       = {Journal of Hydrology},
+  volume        = {608},
+  pages         = {127574},
+  year          = {2022},
+  issn          = {0022-1694},
+  doi           = {https://doi.org/10.1016/j.jhydrol.2022.127574},
+  url           = {https://www.sciencedirect.com/science/article/pii/S0022169422001494},
+  author        = {
+    Esteban Alonso-Gonz\'{a}lez and Jes\'{u}s Revuelto and Steven R. Fassnacht
+    and Juan {Ignacio L\'{o}pez-Moreno}
+  }
+}
+@article{sauquet_2025,
+  author        = {
+    Sauquet, E. and Evin, G. and Siauve, S. and Aissat, R. and Arnaud, P. and
+    B\'erel, M. and Bonneau, J. and Branger, F. and Caballero, Y. and
+    Coll\'eoni, F. and Ducharne, A. and Gailhard, J. and Habets, F. and
+    Hendrickx, F. and H\'eraut, L. and Hingray, B. and Huang, P. and Jaouen, T.
+    and Jeantet, A. and Lanini, S. and Le Lay, M. and Magand, C. and Mimeau, L.
+    and Monteil, C. and Munier, S. and Perrin, C. and Robelin, O. and Rousset,
+    F. and Soubeyroux, J.-M. and Strohmenger, L. and Thirel, G. and Tocquer, F.
+    and Tramblay, Y. and Vergnes, J.-P. and Vidal, J.-P.
+  },
+  title         = {
+    A large transient multi-scenario multi-model ensemble of future streamflow
+    and groundwater projections in France
+  },
+  journal       = {EGUsphere},
+  volume        = {2025},
+  year          = {2025},
+  pages         = {1--41},
+  url           = {https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1788/},
+  doi           = {10.5194/egusphere-2025-1788}
+}
+@article{burn_2010,
+  author        = {Burn, Donald H. and Sharif, Mohammed and Zhang, Kan},
+  title         = {Detection of trends in hydrological extremes for Canadian watersheds},
+  journal       = {Hydrological Processes},
+  volume        = {24},
+  number        = {13},
+  pages         = {1781--1790},
+  keywords      = {flood analysis, low flow events, climate change, trend analysis, Canada},
+  doi           = {https://doi.org/10.1002/hyp.7625},
+  url           = {https://onlinelibrary.wiley.com/doi/abs/10.1002/hyp.7625},
+  eprint        = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/hyp.7625},
+  year          = {2010}
+}
+@article{zomer_2022,
+  title         = {
+    Version 3 of the global aridity index and potential evapotranspiration
+    database
+  },
+  author        = {Zomer, Robert J and Xu, Jianchu and Trabucco, Antonio},
+  journal       = {Scientific Data},
+  volume        = {9},
+  number        = {1},
+  pages         = {409},
+  year          = {2022},
+  publisher     = {Nature Publishing Group UK London}
+}
+@article{knoben_2024,
+  title         = {
+    Setting expectations for hydrologic model performance with an ensemble of
+    simple benchmarks
+  },
+  author        = {Knoben, Wouter JM},
+  journal       = {Hydrological Processes},
+  volume        = {38},
+  number        = {10},
+  pages         = {e15288},
+  year          = {2024},
+  publisher     = {Wiley Online Library}
+}
+@article{singh_2019,
+  title         = {Towards baseflow index characterisation at national scale in New Zealand},
+  journal       = {Journal of Hydrology},
+  volume        = {568},
+  pages         = {646--657},
+  year          = {2019},
+  issn          = {0022-1694},
+  doi           = {https://doi.org/10.1016/j.jhydrol.2018.11.025},
+  url           = {https://www.sciencedirect.com/science/article/pii/S0022169418308801},
+  author        = {
+    Shailesh Kumar Singh and Markus Pahlow and Doug J. Booker and Ude Shankar
+    and Alejandro Chamorro
+  },
+  keywords      = {Baseflow, Quickflow, Prediction, BFI, Random forests technique}
+}
+@article{jaffres_2021,
+  title         = {
+    Hydrological characteristics of Australia: relationship between surface
+    flow, climate and intrinsic catchment properties
+  },
+  journal       = {Journal of Hydrology},
+  volume        = {603},
+  pages         = {126911},
+  year          = {2021},
+  issn          = {0022-1694},
+  doi           = {https://doi.org/10.1016/j.jhydrol.2021.126911},
+  url           = {https://www.sciencedirect.com/science/article/pii/S0022169421009616},
+  author        = {
+    Jasmine B.D. Jaffr\'{e}s and Ben Cuff and Chris Cuff and Iain Faichney and
+    Matthew Knott and Cecily Rasmussen
+  },
+  keywords      = {
+    Climate variability, Non-perennial streams, Surface hydrology, Topography,
+    Soil field capacity, Water infiltration
+  }
+}

src/xclim/data/fr.json

@@ -1499,5 +1499,35 @@
     "long_name": "Indice de précipitation antérieure",
     "description": "Somme pondérée des précipitations quotidiennes, sur une fenêtre de {window} jours et le base exponentielle {p_exp}.",
     "abstract": "Calcul de la somme pondérée des précipitations quotidiennes sur la base d'une fenêtre et d'une base exponentielle."
+  },
+  "ARIDITY_INDEX": {
+    "title": "Indice d'aridité",
+    "long_name": "Indice d'aridité",
+    "description": "Rapport entre les précipitations totales et l'évapotranspiration potentielle.",
+    "abstract": "Rapport entre les précipitations totales et l'évapotranspiration potentielle. Classification basée sur l'indice d'aridité (AI)."
+  },
+  "BASE_FLOW_INDEX_SEASONAL_RATIO": {
+    "title": "Indice de débit de base saisonnier",
+    "long_name": "Indice de débit de base saisonnier",
+    "description": "Indice de débit de base saisonnier et rapport entre les indices de débit de base hivernal et estival.",
+    "abstract": "Indice annuel du débit de base par saison, défini comme le débit moyen minimal sur 7 jours divisé par le débit moyen. Le rapport annuel est la division de l'indice de débit de base hivernal par celui estival."
+  },
+  "LAG_SNOWPACK_FLOW_PEAKS": {
+    "title": "Décalage temporel entre le maximum d'enneigement et les crues",
+    "long_name": "Décalage temporel entre le maximum d'enneigement et les crues",
+    "description": "Nombre de jours entre l'enneigement maximal annuel, mesuré par l'équivalent en eau de la neige, et la date moyenne à laquelle le débit dépasse un certain seuil au cours d'une année donnée.",
+    "abstract": "Nombre de jours entre l'enneigement maximal annuel, mesuré par l'équivalent en eau de la neige, et la date moyenne à laquelle le débit dépasse un certain seuil au cours d'une année donnée."
+  },
+  "RUNOFF_RATIO": {
+    "title": "Taux de ruissellement",
+    "long_name": "Taux de ruissellement",
+    "description": "Rapport entre le volume d'écoulement mesuré au niveau du cours d'eau et le volume total des précipitations sur le bassin versant.",
+    "abstract": "Analyse temporelle : valeurs annuelles calculées à partir des données quotidiennes saisonnières et des données annuelles, en fonction de la fréquence choisie."
+  },
+  "SEN_SLOPE": {
+    "title": "Pente de Theil-Sen",
+    "long_name": "Pente de Theil-Sen",
+    "description": "Analyse de la robustesse temporelle du débit.",
+    "abstract": "Calculer les estimateurs annuels et saisonniers de la pente de Theil-Sen et effectuer le test de Mann-Kendall pour l'évaluation des tendances."
   }
 }

src/xclim/indicators/atmos/_precip.py

@@ -17,6 +17,7 @@
 
 __all__ = [
     "antecedent_precipitation_index",
+    "aridity_index",
     "cffwis_indices",
     "cold_and_dry_days",
     "cold_and_wet_days",
@@ -835,3 +836,14 @@ class DailyPrecipNoResample(Indicator):
     cell_methods="time: sum over days",
     compute=indices.antecedent_precipitation_index,
 )
+
+aridity_index = PrecipWithIndexing(
+    identifier="aridity_index",
+    realm="atmos",
+    units="",
+    long_name="Aridity Index",
+    description="The ratio of total precipitation over potential evapotranspiration."
+    "Classification based on the Aridity Index (AI).",
+    cell_methods="",
+    compute=indices.aridity_index,
+)