Soil moisture is measured by a number of parameters:
- Annual average soil moisture content is projected to decrease by between 5 and 11%.
- Greatest decreases will be in summer and autumn, of up to 20% reductions.
- There will be a reduction of between 5 and 19% in mean available water content throughout the region.
- The number of days when the soil is either saturated or above field capacity will significantly reduce throughout the region, but the converse of this is that there will be a significant increase in the number of dry soil days.
EARWIG does not directly model soil moisture so instead meteorological results, such as rainfall, wind and temperature, from EARWIG were used as input to a hydrological model named the Arno Distribution Model (ADM).
The ADM model outputs catchment-averaged values and does not account for soil heterogeneity. For this reason simple indicators of soil moisture have been considered, using arbitrary thresholds.
The following parameters were considered using the ADM:
Saturation |
This is the point at which the soil cannot hold any more water. This has arbitrarily been set here at 80% of the available water content. |
Field Capacity |
This is the point at which the soil is at its natural capacity. This has arbitrarily been set here at 60% of the available water content. |
Wilt Point |
The wilt point has arbitrarily been set here at 40% of the total available water content. Definitions of wilt point vary and actual values are dependent upon soil type and crop. |
Mean Available Water Content
Results indicate that overall, significant drying is projected, with decreases in mean available water content throughout the region. Changes in this parameter range from reductions of 5 to 19%.
No of Days Saturated Soil (at arbitrary saturation point or above)
There will be large decreases in the number of days when soils are saturated and in some locations this problem will not be experienced by the 2050s.
No of Days Wet Soil (at field capacity or above)
There will be a reduction of between 11 and 30% in the number of days of wet soil.
No of Days Dry Soil (at arbitrary wilt point or below)
There are projected to be significant increases in the number of days with available water content at the arbitrary wilting point or below. Changes are projected to be greatest at Askrigg, Scarborough, York and Hull, but remain very high at all other locations.
Click here to view full table of ADM results.
