Evaporation Pans

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Evaporation Pans

• U.S. Weather Bureau Class A Land Pan
• 4 foot diameter
• 10 inches deep
• well-ventilated (bottom raised 6 inches off
  ground)

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Evaporation Pans

• Measurements differ from PET or AET due to (1)
  boundary effects and (2) limited heat capacity.
• To overcome these problems
• Sunken pans (installed in ground)
• Floating pans

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Evaporation Pans

• Actual evaporation is estimated as
• Ep pan evaporation
• K pan coefficient (0.7 for Class A pan)

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Evaporation Measurement

• Weighing lysimeter
• Eddy-correlation
• Lidar

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Weighing Lysimeter
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Eddy Correlation
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Sonic Anemometer Array
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Raman Lidar
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Lidar Evaporation