Hydrology and Meteorology: A Symbiotic Relationship
Where does all the water go? Land-Atmosphere Interactions are fundamental to Terrestrial Hydrology How much precipitation is intercepted by vegetation? How much precipitation is lost through surface run-off? How much water is returned to the atmosphere by evaporation and transpiration? Depends on surface winds, radiation balance (cloudiness), precipitation characteristics (frequency, intensity) Good et al. 2015
Changing nature of daily rainfall Observed change in total annual precipitation falling in the heaviest 1% of daily events Heavy daily/sub-daily rainfall will likely increase surface run-off (and soil erosion) and reduce terrestrial storage Is the hydrological response to less frequent, but more intense rainfall, non-linear? What does this tell us about the coupling frequency between meteorological and hydrological systems? From US 4th National Climate Assessment 2018
‘Closing the scale gap’ with Kilometer-scale Modelling Revolution in Weather and Flood Forecasting, Climate Downscaling Rainfall prediction for Storm Desmond: Lake District and Carlisle flooding 4 km 12 km 1 km Substantial improvements in localised heavy rainfall Substantial improvements in orographically forced rainfall Much finer landscape details
Human interference in the hydrological cycle: What are the weather/climate impacts? GRACE Groundwater storage annual trends for 37 largest aquifers (2003 - 2013) One third of the largest aquifers are being depleted while receiving little to no recharge
Fully integrated hydro-meteorological observing and prediction systems? Integration with the atmosphere to ensure consistency in evapo- transpiration across the land-atmosphere interface Representation of the space/time heterogeneity of precipitation - fundamentally important for surface water/flash flooding and the functioning of terrestrial water cycle. Integration with the coastal ocean to represent river outflows (including nutrients), estuaries and the effects of tides and storm surges. Integration of the water cycle with other key terrestrial cycles to ensure consistency between water, heat, carbon and nitrogen cycles - critical for understanding and predicting the Earth system. Internally consistent assessments of climate change impacts on hydro-meteorological hazards and water availability.