A simplified method for remote sensing of daily canopy transpiration - a case study with direct measurements of canopy transpiration in soybean canopies
| Autor: | M. S. Moran, Y. Inoue |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | International Journal of Remote Sensing. 18:139-152 |
| ISSN: | 1366-5901 0143-1161 |
| DOI: | 10.1080/014311697219321 |
| Popis: | Daily values of actual canopy transpiration were obtained by stemflow heat balance method (SFG) in drought-stressed, waterlogged, and periodically-irrigated soybean canopies (Glycine max Merr.). Spectral and thermal infrared measurements and basic meteorological factors were obtained over the canopies under a wide range of sky conditions. The potential canopy transpiration (Trp ) was found to be linearly correlated to the product of an instantaneous measurement of spectral vegetation index (SAVI) and daily sum of incoming solar radiation (Rs ), as Trp = α SAVI Rs . The proportionality constant α was 0.28 for soybean canopies. On the basis of this simplified relation, a simple method was proposed to estimate the daily values of actual canopy transpiration (Tra ). The method utilizes either instantaneous measurements of plant and air temperature differential (tplant - tair ) or CWSI (Crop Water Stress Index) around mid-day as a major input. Both tplant - tair and CWSI can be estimated by thermal re... |
| Databáze: | OpenAIRE |
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