Effect of spatial resolution on thermal and near-infrared sensing of canopies

James Alan Smith; Jerrell R. Ballard Jr.

doi:10.1117/1.602193

1 August 1999 Effect of spatial resolution on thermal and near-infrared sensing of canopies

James Alan Smith, Jerrell R. Ballard Jr.

Optical Engineering, Vol. 38, Issue 8, (August 1999). https://doi.org/10.1117/1.602193

Satellite observations of agricultural and other plant canopies in the thermal and near iR regime have generally been at spatial scales of tens to hundreds of meters. Advances in sensor technology will extend our capabilities for IR measurements from space to yield improved spatial resolutions. We explore the variability in brightness temperature and the covariation of the normalized difference vegetation index (NDVI) with brightness temperature as a function of viewing geometry and changing spatial resolution. Using 3-D models for both canopy reflectance and thermal infrared exitance, we employ a theoretical analysis for an agricultural scene. The directional viewing effects and correlation between the NDVI and brightness temperature are found to be scale independent and in agreement with experiment. Directional anisotropy in brightness temperature and NDVI are calculated to be less than 7 to 12% respectively for zenith view angles less than 30 deg, but range up to 22 to 40% for zenith view angles of 60 deg. Analysis of variation in local standard deviations with spatial resolution shows a maximum peak corresponding to crop row spacing with rapid fall-off at larger scales.

Citation Download Citation

James Alan Smith and Jerrell R. Ballard Jr. "Effect of spatial resolution on thermal and near-infrared sensing of canopies," Optical Engineering 38(8), (1 August 1999). https://doi.org/10.1117/1.602193

Published: 1 August 1999

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available