Changes in hydrological indicators
In this version, all indicators for river discharge and flood recurrence have been supplemented with an additional scenario in which the changes can be calculated for unregulated discharge. Two new indicators, "Days with low soil moisture," and “River discharge MLQ” was added, and the ensemble of climate models used for all hydrological indicators was extended with one new member. Flood recurrence with different return periods are now omitted for 11 areas where the values were assessed as too uncertain.
This update to the hydrological climate scenario service includes several changes:
The largest change is that unregulated water flow has been added as a complement to the river discharge and flood recurrence indicators that existed before, where the calculations are made with current regulations also for the future. For these, a choice for regulation scenario has been added to the menu in the climate scenario service.
For indicators related to flood recurrence for the current regulations and at a specific return period, the underlying statistics were evaluated, revealing that 11 areas do not meet the quality requirements. No results are displayed for these eleven areas in the updated climate scenario service.
A new indicator "Days with low soil moisture" was added. Soil moisture lower than 50% of the field capacity in the root zone is defined as low.
The indicator "River discharge (MLQ)" was added. MLQ is an average value of each year's lowest river discharge.
For the indicator "Low flow days” the unit is changed from percentage to days.
An ensemble of combined global and regional climate models is used as input for the hydrological model calculations. In the previous version of the hydrological climate scenario service, 16 ensemble members were used. An additional member has been added for this version. The new ensemble affects all hydrological indicators, but the change is generally small. The relative change is most significant for the indicator "Snow water content (max)" because the new ensemble member shows a smaller decrease compared to most ensemble members.