Initial WIS 2 Topic Hierarchy for Hydrology

[disiiwash]

Overview of proposal*

1. Respond to the activities within some projects that support exchange of hydrology data and
2. This is part of WHOS WIS pilot and allow publication of notification messages for the exchange of hydrology data into WIS2.0
3. This is part of the bigger task of the integration of Hydrology data into WIS2.0 (WHOS alignment with WIS2.0), allow exchange of a subset of hydrology data within WIS2.0
4. Start implementation through the WHOS DAB and a few countries by 2025

Amendment details (draft)*

updated 03 October 2025

Add sub-disciplines to the hydrology discipline.

Name	Description	Source
space-based-observations	Space based observations
surface-based-observations	Surface based observations
subsurface-based-observations	Subsurface based observations

Add topics to space-based-observations sub-discipline

Name	Description	Source
hydrology/space-based-observations/soil	Soil

Add topics to subsurface-based-observations sub-discipline

Name	Description	Source
hydrology/subsurface-based-observations/groundwater-quantity	Groundwater quantity
hydrology/subsurface-based-observations/soil	Soil

Name	Description	Source
hydrology/subsurface-based-observations/groundwater-quantity/well	Well
hydrology/subsurface-based-observations/groundwater-quantity/aquifer	Aquifer

Add topics to surface-based-observations sub-discipline

Name	Description	Source
hydrology/surface-based-observations/atmospheric	Atmospheric
hydrology/surface-based-observations/water-quantity	Water Quantity

Name	Description	Source
hydrology/surface-based-observations/atmospheric/air	Air
hydrology/surface-based-observations/atmospheric/precipitation	Precipitation
hydrology/surface-based-observations/atmospheric/wind	Wind

Name	Description	Source
hydrology/surface-based-observations/water-quantity/ice	Ice
hydrology/surface-based-observations/water-quantity/lake	Lake
hydrology/surface-based-observations/water-quantity/reservoir	Reservoir
hydrology/surface-based-observations/water-quantity/snow	Snow
hydrology/surface-based-observations/water-quantity/stream	Stream

list of topics

1. hydrology/space-based-observations/soil
2. hydrology/subsurface-based-observations/groundwater-quantity/aquifer
3. hydrology/subsurface-based-observations/groundwater-quantity/well
4. hydrology/subsurface-based-observations/soil
5. hydrology/surface-based-observations/atmospheric/air
6. hydrology/surface-based-observations/atmospheric/precipitation
7. hydrology/surface-based-observations/atmospheric/wind
8. hydrology/surface-based-observations/water-quantity/ice
9. hydrology/surface-based-observations/water-quantity/lake
10. hydrology/surface-based-observations/water-quantity/reservoir
11. hydrology/surface-based-observations/water-quantity/snow
12. hydrology/surface-based-observations/water-quantity/stream
    13. hydrology/surface-based-observations/water-quantity/water

Requestor(s)*

Leoni Paolo on behalf of TT-WIS2 for Hydrology

Consultations

TT-WIS2 for hydrology experts, INFCOM experts and other hydrology experts

Describe WIS2 data publication plans associated with the proposal

1. Subset of publicly shared data in WHOS through WHOS DAB
2. Subset of real time surface water and ground real data form global data centers
3. Hydro Services exchanging file based data e.g Canada and some within CREWS project

Comments

[disiiwash]

@PaoloLeoniIT kindly check and advice, I have submitted this proposal on your behalf.

[amilan17]

This is a reorganization of the proposed topics:

Amendment details*

Add sub-disciplines to the hydrology discipline.

Name	Description	Source
space-based-observations	Space based observations
surface-based-observations	Surface based observations
subsurface-based-observations	Subsurface based observations

add topics to sub-disciplines

Name	Description	Source
hydrology/space-based-observations/soil	Soil
hydrology/space-based-observations/surface-water	Surface water
hydrology/subsurface-based-observations/groundwater-quantity	Groundwater quantity
hydrology/subsurface-based-observations/soil	Soil
hydrology/surface-based-observations/atmospheric	Atmospheric
hydrology/surface-based-observations/water-quantity	Water Quantity

add topics to hydrology/space-based-observations/soil:

Name	Description	Source
soil-moisture	Soil moisture	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12277
soil-type	Soil type	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/246

add topics to hydrology/space-based-observations/surface-water/:

Name	Description	Source
snow-cover-extent	Snow cover extent	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/628

Add topics to hydrology/subsurface-based-observations/groundwater-quantity/:

Name	Description	Source
groundwater-storage	Storage or aquifer volume	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12255
groundwater-level	Groundwater level	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/166

Add topics to hydrology/subsurface-based-observations/soil/:

Name	Description	Source
infiltration-rate	Infiltration rate	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12261
land-surface-temperature	Land surface temperature	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/389
soil-moisture	Soil moisture	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12277

add topics to hydrology/surface-based-observations/atmospheric/:

Name	Description	Source
air-temperature	Air temperature	https://codes.wmo.int/wmdr/ObservedVariableAtmosphere/_224
wind	wind	https://codes.wmo.int/wmdr/ObservedVariableAtmosphere/_307

add topics to hydrology/surface-based-observations/water-quantity/:

Name	Description	Source
stream-level	Stream level	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/172
stream-discharge	Stream flow and stream discharge	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/171
lake-level	Lake level	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/168
lake-temperature	Lake surface temperature and lake temperature	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/410
water-temperature	Water temperature	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/410
reservoir-storage	Reservoir storage including lake volume	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12279
water-level	Water level	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12252
depth-snowfall	Depth of snowfall	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/627
stream-index-velocity	Stream index velocity	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12282
stream-velocity	Stream velocity	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12322
suspended-sediment-discharge	Suspended sediment discharge	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12281
suspended-sediment-load	Suspended sediment load	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12272
snow-water-equivalent	Water equivalent of snow cover or snowfall	https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/631

list of topics

1. hydrology/space-based-observations/soil/soil-moisture
2. hydrology/space-based-observations/soil/soil-type
3. hydrology/space-based-observations/surface-water/snow-cover-extent
4. hydrology/subsurface-based-observations/groundwater-quantity/groundwater-storage
5. hydrology/subsurface-based-observations/groundwater-quantity/groundwater-level
6. hydrology/subsurface-based-observations/soil/infiltration-rate
7. hydrology/subsurface-based-observations/soil/land-surface-temperature
8. hydrology/subsurface-based-observations/soil/soil-moisture
9. hydrology/surface-based-observations/atmospheric/air-temperature
10. hydrology/surface-based-observations/atmospheric/wind
11. hydrology/surface-based-observations/water-quantity/stream-level
12. hydrology/surface-based-observations/water-quantity/stream-discharge
13. hydrology/surface-based-observations/water-quantity/lake-level
14. hydrology/surface-based-observations/water-quantity/lake-temperature
15. hydrology/surface-based-observations/water-quantity/water-temperature
16. hydrology/surface-based-observations/water-quantity/reservoir-storage
17. hydrology/surface-based-observations/water-quantity/water-level
18. hydrology/surface-based-observations/water-quantity/depth-snowfall
19. hydrology/surface-based-observations/water-quantity/stream-index-velocity
20. hydrology/surface-based-observations/water-quantity/stream-velocity
21. hydrology/surface-based-observations/water-quantity/suspended-sediment-discharge
22. hydrology/surface-based-observations/water-quantity/suspended-sediment-load
23. hydrology/surface-based-observations/water-quantity/snow-water-equivalent

[amilan17]

definition of stream velocity includes stream index velocity...

[amilan17]

are lake-temperature and water-temperature considered quantities?

[rodicanitu]

How will "snow" under cryosphere and "snow cover extent" under hydrology be reconciled. SCE is a variable of snow. If the hyerarchy goes to the variable level, is there value in duplicating the variables in the hierarchy? if yes, then, i think it's easier to use the variables from the codes.

[disiiwash]

How will "snow" under cryosphere and "snow cover extent" under hydrology be reconciled. SCE is a variable of snow. If the hyerarchy goes to the variable level, is there value in duplicating the variables in the hierarchy? if yes, then, i think it's easier to use the variables from the codes.

The best way to reconcile this will be then to avoid going to specific parameters and use i.e hydrology/surface-based-observations/water-quantity/snow

[PaoloLeoniIT]

definition of stream velocity includes stream index velocity...

Thank you, Anna.
I would suggest editing as follows:

stream-index-velocity | Stream Index Velocity | https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12282

stream-velocity | Stream Velocity | https://codes.wmo.int/wmdr/ObservedVariableTerrestrial/12322

[PaoloLeoniIT]

are lake-temperature and water-temperature considered quantities?

Yes, both lake temperature and water temperature are considered physical quantities. This is because physical quantities are measurable characteristics of physical systems, and temperature fits this definition perfectly.

[amilan17]

note, that there is a WIGOS Metadata proposal for FT2025-2 that will retire air temperature with notation 224 and update name and definition of notation 12166.
see issue wmo-im/wmds#583

the url for 224 will still be valid, but we may want to change the source for hydrology/surface-based-observations/atmospheric/air-temperature topic after fast-track approval

[amilan17]

@disiiwash @PaoloLeoniIT for my understanding can you explain how the following topics are hydrological in nature?

hydrology/surface-based-observations/atmospheric/air-temperature
hydrology/surface-based-observations/atmospheric/wind