1. Active/Passive Microwave Observations Provide Essential Climate Variables for Studying Hydrologic Cycle Probably the Greatest Consequences of Our Warming Climate will be Related to Changes to Hydrologic Cycle and General Circulation: Drought, Floods, Severe Storms Is the Hydrologic Cycle Accelerating? Is the Walker Circulation Intensifying? Is the Hadley Cell becoming More Energetic? How will Precipitation Increase with Global Warming? Slide 1 There is no Substitute for Satellite Observations Continuous Satellite Data is an Absolute Requirement Numerical Assimilation Reanalysis and Climate Model are not Sufficient Satellite Microwave Measurements Provide Essential Climate Variables  Ocean Vector Winds  Sea Surface Height, Temperature, and Salinity  Atmospheric Temperature, Water Vapor, Cloud Water, and Rain Rate  Sea Ice Concentration  Soil Moisture and Snow Cover

2. Slide 2 Now Future 1: More Water Vapor, Unchanged Circulation Future 2 : More Water Vapor, Slower Circulation Two Possible Future Scenarios for Rain 2% or 6% Increase in Rain per 1 K of Warming ?

3. Slide 3 Quarter-Century Trends from Satellites