| タイトル | Diurnal patterns of wheat spectral reflectances and their importance in the assessment of canopy parameters from remotely sensed observations |
| 本文（外部サイト） | http://hdl.handle.net/2060/19830006288 |
| 著者（英） | Idso, S. B.; Jackson, R. D.; Reginato, R. J.; Pinter, P. J. |
| 著者所属（英） | Department of Agriculture |
| 発行日 | 1982-09-01 |
| 言語 | eng |
| 内容記述 | Spectral reflectances of Produra wheat were measured at 13 different times of the day at Phoenix, Arizona, during April 1979 using a nadir-oriented hand-held 4-band radiometer which had bandpass characteristics similar to those on LANDSAT satellites. Different Sun altitude and azimuth angles caused significant diurnal changes in radiant return in both visible and near-IR regions of the spectrum and in several vegetation indices derived from them. The magnitude of these changes were related to different canopy architecture, percent cover and green leaf area conditions. Spectral measurements taken at each time period were well correlated with green leaf area index but the nature of the relationship changed significantly with time of day. Thus, a significant bias in the estimation of the green leaf area index from remotely sensed spectral data could occur if sun angles are not properly accounted for. |
| NASA分類 | EARTH RESOURCES AND REMOTE SENSING |
| レポートNO | 83N14559
NAS 1.26:169566
EW-U2-04349
E83-10050
JSC-18561
NASA-CR-169566 |
| 権利 | No Copyright |
