Chapter 18

Evapotranspiration Measurement

Outline:

• Evaporation measurement
  • Direct- lysimeters, pan evaporation, air moisture profiling
  • Indirect- mass transfer empirical methods
• Evaporation by energy balance approach
  • evaporative heat flux
  • sensible heat flux
  • net radiation
  • soil heat storage
  • Bown Ratio
• Evapotranspiriation estimation
  • Bowen Ratio
  • Penmen-Monteith equation

Textbook reading:

• none.

Other reading:

• Hsiao, T.C. 1990. Crop water requirement and productivity. Proceedings of the 5th International Conference on Irrigation, Tel-Aviv, Israel. download here
• "Evaporation and Energy balance" handout download here

Related web links:

• General ET links
• What is evapotranspiration?
• Evapotranspiration measruement strategy
• AgriMet - agricultural weather network for Pacific Northwest ET estimates.
• ET and droughts

Video Podcast: Evapotranspiration

This 62-minute presentation lays out the basic concepts and measurement approaches for water and energy fluxes associated with evaporation, transpiration, and evapotranspiration.

• 640 x 480 (480p) format that balances speed and quality. (900 MB file)
• 1920 x 1280 (HD) format that provides larges size and best quality. (5.2 GB file)

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