1. Precipitation Measurement - Standard Gauge
The Good:
Simple
Inexpensive
The Bad:
Maintenance
Evaporation
- No digital output
- Spatial extent

2. Precipitation Measurement - Weighing Gauge
The Good:
Time series
Simple (mostly)
The Bad:
Messy maintenance
Moving parts
- No digital output
Spatial extent
Pretty expensive

3. Precipitation Measurement - Tipping Bucket
The Good:
Digital time series
Accurate
The Bad:
Snow?
- Loss during tips

4. Precipitation Measurement - Piezoelectric
The Good:
Very accurate
Digital data logger
The Bad:
Expensive
- Spatial extent

5. Doppler Radar
A standard rain gage will have a sample area of ~ ft2, but radar will sample ~ hundreds mi2

7. Stick gage - $400
Tipping bucket - $700
Weighing - $5,000+
Doppler - $5,000,000

8. Measurement Errors Placement (near structures) Wind
Unequal distribution (rain is a spatial process)
Placement:

9. Wind Error 1. Reduced effective catch area.
2. Rain gage will cause wind to lift and accelerate.

11. Wind

12. Double Alter Wind Shield

13. Dealing with Spatial Variability
Arithmetic Mean
Thiessen Polygon
Interpolation

15. Cloud Drip Icacos , Puerto Rico 423 mm/yr Pico del Este, Puerto Rico
Monteverde, Costa Rica
350 mm/yr
Some tropical watershed research shows that cutting cloud forests actually reduces stream flow.

16. Hail and sleet are frozen rain, where as snow crystals form when water vapor condenses directly into ice.
As much as 75 percent of water supplies in the western United States are derived from snowmelt .
300 inches of snow that the Lake Tahoe area receives is equivalent to about 30 inches of rain.

17. Snow Measurement
Snow pack Core sampling
Snow “Pillow”

18. Getting Rain Data http://fawn.ifas.ufl.edu http://data.cuahsi.org
SJRWMD
National Climate Data Center
National Weather Service (NOAA)