Accession Number:

AD0609740

Title:

The Energy Budget at the Earth's Surface: Vertical Fluxes Within the Vegetative Canopy of a Corn Field, 1962.

Descriptive Note:

Interim rept.,

Corporate Author:

AGRICULTURAL RESEARCH SERVICE ITHACA N Y

Personal Author(s):

Report Date:

1964-08-01

Pagination or Media Count:

98.0

Abstract:

The energy budget approach was utilized to evaluate the vertical fluxes of sensible and latent heat by layers within a fully grown corn crop. The necessary data including net radiation, temperature and water vapor pressure profiles within the crop, as well as the smaller storage terms, were measured during 10-minute periods throughout the daytime hours. An exponential relation with leaf area approximated the extinction of net radiation within the crop. The temperature profiles were characterized in midday by the establishment of a warm air layer within the center of the crop. The calculated exchange coefficients spanned a range of three orders of magnitude. Transpiration accounted for 46 of the net radiation soil evaporation, 13 and sensible heat, 32. Although the crop transpired most rapidly near the top, the data demonstrate the influence of plant controlling factors in addition to the microclimatological parameters studied. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE