Upload
teenie
View
71
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Precipitation Measurement - Standard Gauge. The Good: Simple Inexpensive The Bad: Maintenance Evaporation - No digital output - Spatial extent. Precipitation Measurement - Weighing Gauge. The Good: Time series Simple (mostly) The Bad: Messy maintenance Moving parts - PowerPoint PPT Presentation
Citation preview
Precipitation Measurement - Standard GaugeThe Good:- Simple- InexpensiveThe Bad:- Maintenance- Evaporation- No digital output- Spatial extent
Precipitation Measurement - Weighing GaugeThe Good:- Time series- Simple (mostly)The Bad:- Messy maintenance- Moving parts- No digital output- Spatial extent- Pretty expensive
Data Logger
Precipitation Measurement - Tipping BucketThe Good:- Digital time series- AccurateThe Bad:- Snow?- Loss during tips
Sensor frame
Sensor cover
Piezo detector
Electronics + Software
Precipitation Measurement - Piezoelectric
The Good:- Very accurate- Digital data loggerThe Bad:- Expensive- Spatial extent
Acoustic Rain Gage
The Good:- Very accurate- Spatially explicit- Digital data loggerThe Bad:- Expensive
Doppler Radar
A standard rain gage will have a sample area of ~ ft2, but radar will sample ~ hundreds mi2
Stick gage - $400Tipping bucket - $1,000Weighing - $5,000+Doppler - $5,000,000
Measurement Errors•Placement (near structures)•Wind
•Unequal distribution (rain is a spatial process)
Placement:
Wind
1. Reduced effective catch area.
2. Rain gage will cause wind to lift and accelerate.
Wind Error
Double Alter Wind Shield
Arithmetic Mean
Thiessen Polygon
Interpolation
Dealing with Spatial Variability
Icacos , Puerto Rico
423 mm/yr
Pico del Este, Puerto Rico
340 mm/yr
Monteverde, Costa Rica
350 mm/yr
Cloud Drip
Some tropical watershed research shows that cutting cloud forests actually reduces stream flow.
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.
Snow Measurement
Snow pack Core sampling
Snow “Pillow”
Getting Rain Data• http://fawn.ifas.ufl.edu• SJRWMD• National Climate Data
Center• National Weather Service
(NOAA)