1. Water Cycle Extremes Sushel Unninayar NASA/GSFC, GESTAR/MSU
13th IGWCO Meeting (&GEOGLOWS) May 19, 2017 National Water Center, Tuscaloosa, AL
Water Cycle Extremes Sushel Unninayar NASA/GSFC, GESTAR/MSU

2. WCEs--Impacts
WCEs impact space scales ranging from local (1 – 10 km) to sub-regional (~100km) to regional/continental (~1000 km)
Time scales range from hours/days to weeks to months to years to decades/century
Impacts range from Millions ($s) to multi-Billions ($s)
Power outages due to weather extremes cost (USA) approx. $40B to $150B per year. Loss of lives. 1% mitigation due to EO = $1.5B!
WCEs are associated with Weather anomalies, climate variability, El-Nino, decadal oscillations, global climate change.

3. Water Cycle Extremes
Extremes in the water cycle are becoming more frequent and intense as the climate changes
Many of the impacts of these climate-related extremes (e.g., droughts, floods) are mediated through the water cycle.
They are particularly important because of their large impacts on socio-economic structures/activities and on natural ecosystems.
WCEs are at the center of changes in the water-food-energy-health-ecosystem nexus.
They provide a cross-cutting focus for water cycle research and applications; New initiative of the USGCRP

4. Challenges to Observing/Modeling Global Water Cycle Processes
All Essential Water variables are not directly observed or sensed (Satellite)
Parameterization of processes (in models) are in various stages of evolution/sophistication
Space/time resolutions are issues in both satellite observations and in-situ data sets.
Forecasting/predicting WCEs are problematic
In-situ typically lack global spatial coverage. High density station data are not exchanged internationally. Station networks are deteriorating
Space-based remote sensing observing systems can provide global coverage but often lack high time resolution

5. Satellite Global Observing System (Ref
Satellite Global Observing System (Ref. GEO) currently measure (or deliver via data assimilation models) many elements of the Earth-Climate system--EWVs: How do we maximize their use in monitoring/modeling predicting extremes? What next generation observing/modeling/data/information systems are required to meet needs???