HYD151
Field Methods in Hydrology

WEEK 2

Lecture 05: Precipitation Measurement and Sampling

Outline:
Precipitation basics
Requirements for rainfall
Moisture saturation and nuclei
Cooling mechanisms
frontal lifting
frontal collision
convection
orography
Forms of precipitation
Spatial and temporal variability
World records
Point measurement methods
Non-recording gages
NWS 8" diameter gage
Recording gages
Tipping bucket rain gages
Weighing bucket precipitation gages
Float and pressure transducer gages
Optical gages
Siting factors
Turbulence
Obstructions
Regional measurement methods
Radar
Satellite

Textbook reading:
none.

Other reading:
Precipitation. In (Brakensiek, D. L., Osborn, H. B., and Rawls, W. J., eds.) 1979. Field Manual for Research in Agricultural Hydrology. United States Department of Agriculture, Agricultural Handbook #224, p. 1-45.download here

Click Here to view the tipping bucket on-line demonstrations

Related web links:
Theory
Rainfall and its variability
Rainfall variability in Australia
Precipitation Variability at High Spatial Resolution in the Desert Southwest
World Rainfall Extremes

Field Methods
8-inch non-recording standard rain gage description
Tipping Bucket gage demonstration Asos tipping bucket rain gage
Method for estimating effective rainfall rate
NEXRAD Radar information

Data Sources
National Climate Data Center- may cost $$$

Lecture 05: Snow Measurement

Snow Surveys and Water Supply Forcasting
Snow survey equipment- snow corer, snow pillows, remote sensing
Water Supply Forecasting
data inputs- snow pack, reservoirs, and rainfall
statistical models

Textbook reading:
none.

Other reading:
Koontz, L.L. 1996. Measuring Snowfalls. http://members.cox.net/wxr/koontz.htm.



Related web links:
The Snow Booklet- a guide to measuring snow in the U.S.
Ho-to guide to snow surveys
California Snow Course Sites
Snow Pillow information
Snow Pillow picture
Example of Snow Pillow data

Assignment 2: Experimental Design and Spatial Characterization

Outline:
Be prepared to go out into the field! We will be out for 2 hrs.

Textbook reading:
none.

Other reading:
none.

Homework: Due 01/30/08 (~1.5 weeks)
You do not need to use the full report format on this homework. Use a simplified report format but continue to show all calculations, graphs, maps, etc as clearly as possible.

Related web links:
none.