Weather-Climate Continuum The Hydrologic perspective

1. Weather-Climate Continuum The Hydrologic perspective The Hydrologic Cycle Source: Sustainable Water Resources Alliance • weatherand climate intimately connected to surface and subsurface • important feedback between sub/ surface and atmosphere precipitation partitioning of energy into latent and sensible heat • soilmoisture • vegetation

2. Weather-Climate Continuum Methods, tools and concepts • Weather (short-term) • USES: • flash flood forecasting • hydroelectric generation • METHODS and TOOLS • Numerical Models • uncoupled (no feedback) • Climate (seasonal, annual, decadal…) • USES: • flood forecasting • water supply • ecologic purposes • hydroelectric generation • navigation • flood plain management • climate change scenarios • METHODS and TOOLS • Numerical Models • coupled to General Circulation Models of the atmosphere

3. Weather-Climate Continuum Methods, tools and concepts • Weather (short-term) • Uncertainty Analysis • Inputs: • Precipitation, wind, pressure, temperature, etc • Outputs: • Forecaster SKILLS • volume, time to peak, magnitude of peak • probability measure • Initial conditions and soil moisture • Model • Climate (seasonal, annual, decadal…) • Uncertainty Analysis • Inputs: available at larger spatial scales than needed for hydrologic predictions (General Circulation Models) • Precipitation wind, pressure, temperature, vegetation, etc • Outputs: • Automatic algorithms for calibration • volume, time to peak, magnitude of peak • probability measure • Initial conditions and soil moisture • Model

4. Summary: no big differences in tools and methods between weather & climate in hydrology climate more detailed representation of physical processes main issue is the spatial and temporal scale of atmospheric variables • 100-yr precipitation event might/might not produce 100-yr flood • Hydrologic Models predict volume/time  need conversion to water elevation using topographic information (flood mapping)