Groundwater
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It is estimated that groundwater accounts for about 30% of the world’s total freshwater resources, and it is by far the largest available reservoir of liquid freshwater. Groundwater counts in average for one third of the freshwater consumed by humans, but at some parts of the world, this percentage can reach up to 100%. Climate change affects groundwater recharge rates through changes in precipitation and evapotranspiration. However, attributing observed groundwater change to climate change is difficult because of the influence of land-use change and groundwater abstraction. The extent to which groundwater recharge and storage has already been affected by climate change is widely unknown. Climate change can also affect groundwater through saltwater intrusion in coastal aquifers as sea level rises. |
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| Domain: | Terrestrial | |
| Subdomain: | Hydrology | |
| Scientific Area: | Hydrosphere | |
| ECV Steward: | Claudia Ruz Vargas | |
| Products: | Groundwater Storage Change, Groundwater Level | |
Groundwater level
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Figure: Groundwater level time series of well 32_16, Sweden from 01/01/1976 until 23/01/2019, extracted from the Global Groundwater Monitoring Network (GGMN). |
ECV Products and Requirements
These products and requirements reflect the Implementation Plan 2022 (GCOS-244).
The requirements are found in the complete 2022 ECVs Requirements document as well: ECV Groundwater.
| Products | Groundwater Storage Change | Groundwater Level | ||
| (*) | Unit | Values | Values | |
| Horizontal Resolution | G | km | ≤ 100 | - |
| B | - | |||
| T | 200-300 | 1 | ||
| Vertical Resolution | G | - | - | |
| B | - | - | ||
| T | - | - | ||
| Temporal Resolution | G | month | 0.5 | 0.5 |
| B | 1 | 1 | ||
| T | 3 | 3 | ||
| Timeliness | G | month | <1 | 2-3 (days) |
| B | 1 | 0.5 | ||
| T | 12 | 1 | ||
| Required Measurement Uncertainty (2-sigma) | G | mm | 1 | 1 |
| B | ||||
| T | 10 | 30 | ||
| Stability | G | mm y-1 | 1 | 1 |
| B | ||||
| T | 10 | 10 | ||
(*) Goal (G): an ideal requirement above which further improvements are not necessary. Breakthrough (B): an intermediate level between threshold and goal which, if achieved, would result in a significant improvement for the targeted application. The breakthrough value may also indicate the level at which specified uses within climate monitoring become possible. It may be appropriate to have different breakthrough values for different uses. Threshold (T): the minimum requirement to be met to ensure that data are useful.
Data Sources
This list provides sources for openly accessible data sets with worldwide coverage for which metadata is available. It is curated by the respective GCOS ECV Steward(s). The list does not claim to be complete. Anyone with a suitable dataset who wishes it to be added to this list should contact the GCOS Secretariat.
- Gravity Recovery and Climate Experiment (GRACE) Data
http://grace.jpl.nasa.gov/data/get-data/
- Global Groundwater Monitoring Network (GGMN) by the International Groundwater Resources Assessment Center (IGRAC)
https://www.un-igrac.org/special-project/ggmn-global-groundwater-monito…
- UN Environment GEMS/Water Data Centre from the International Centre for Water Resources and Global Change
- Satellite ECV Inventory by the CEOS/CGMS Working Group on Climate (WGClimate)
