Accession Number:

ADA106741

Title:

An Alternate Approach to the Measurement of Soil Surface Heat Flux.

Descriptive Note:

Master's thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s):

• Merrill,Bruce Rex

Report Date:

1981-01-01

Pagination or Media Count:

59.0

Abstract:

A new approach to the measurement of the conductive heat flux at the soil surface is presented. This approach provides the means to make measurements of the soil conduction heat flux. By sensing the temperature of the soil surface and using a temperature control circuit one forces an artificially created portion of the soil surface to mimic the temperature of the natural surface. By monitoring the power to maintain this control one makes a direct measurement of the conduction heat flux at the soil surface. Although the present instrument works only when the conduction heat flux is directed out of the ground there is nothing in principle to prevent the instrument from working when the flux is in the other direction. The error analysis shows that the two main sources of error are due to the electronics design and the errors associated with measuring the true temperature of a surface. Laboratory testing shows that unexplained error amounts to only a few percent at most. Laboratory testing also shows that the instrument is capable of measuring fluxes down to tenths of milliwatts per square centimeter. Author

Descriptors:

• *HEAT FLUX
• TEMPERATURE
• ELECTRONIC EQUIPMENT
• THESES
• VARIATIONS
• SURFACES
• SOILS
• MEASURING INSTRUMENTS
• ERRORS
• THERMAL CONDUCTIVITY

Subject Categories:

• Soil Mechanics
• Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE