TWS is the total amount of water stored in all continental storage compartments (ice caps, glaciers, snow cover, soil moisture, groundwater, surface water bodies, water in biomass). The change of TWS over time balances the budget of the water fluxes precipitation, evapotranspiration and runoff, i.e., it closes the continental water balance. TWS changes thus represent the net effect of climate variability and climate change as well as of anthropogenic impacts on the water cycle.
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 Terrestrial Water Storage.
Products | | Terrestrial Water Storage Anomaly |
| (*) | Unit | Values |
Horizontal Resolution | G | km | 1 |
B | 10 |
T | 200 |
Vertical Resolution | G | | - |
B | - |
T | - |
Temporal Resolution | G | d | 1 |
B | |
T | 30 |
Timeliness | G | d | 1 |
B | |
T | 60-90 |
Required Measurement Uncertainty (2-sigma) | G | mm | 1 |
B | |
T | 20 |
Stability | G | mm y-1 | <1 |
B | |
T | <5 |
(*) 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.