The ratio of transmitted near-infrared radiation to photosynthetically active radiation (PAR) increases in proportion to the adsorbed PAR in the canopy

Atsushi Kume, Kenlo N. Nasahara, Shin Nagai, Hiroyuki Muraoka

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The daily total photosynthetically active radiation (400-700 nm, PAR) and near-infrared radiation (700-1000 nm, NIR) were measured in the understory beneath the canopy (PARt and NIRt) and above the canopy (PARi and NIRi) of a Japanese cool-temperate deciduous broad-leaved forest during the snow-free period (May to November). The integration of spectral radiation for NIR and that for PAR, and the daily integrations of instantaneous NIR and PAR, reduced the noises from the optical difference in spectrum and from canopy structure heterogeneity, sky condition and solar elevation. PARi/PARt was linearly related to NIRt/PARt (R2 = 0.96). The effect of cloudiness was negligible, because the fluctuation of NIRi/PARi was quite small regardless of season and weather conditions compared with the range of NIRt/PARt in the forest. The ratio of NIRt/PARt beneath the canopy was log-linearly related to the in situ leaf area index (LAI) with a wide range from 0 to 5.25 (R2 = 0.97). We conclude that seasonal changes in fAPAR (= 1 - PARt/PARi) and LAI of a canopy can be estimated with high accuracy by transmitted NIRt and PARt beneath the canopy.

Original languageEnglish
Pages (from-to)99-106
Number of pages8
JournalJournal of Plant Research
Volume124
Issue number1
DOIs
Publication statusPublished - Jan 1 2011

Fingerprint

near infrared radiation
photosynthetically active radiation
canopy
leaf area index
snow
understory
weather

All Science Journal Classification (ASJC) codes

  • Plant Science

Cite this

The ratio of transmitted near-infrared radiation to photosynthetically active radiation (PAR) increases in proportion to the adsorbed PAR in the canopy. / Kume, Atsushi; Nasahara, Kenlo N.; Nagai, Shin; Muraoka, Hiroyuki.

In: Journal of Plant Research, Vol. 124, No. 1, 01.01.2011, p. 99-106.

Research output: Contribution to journalArticle

@article{c59253239f8c416e80f67b157cfbc3ea,
title = "The ratio of transmitted near-infrared radiation to photosynthetically active radiation (PAR) increases in proportion to the adsorbed PAR in the canopy",
abstract = "The daily total photosynthetically active radiation (400-700 nm, PAR) and near-infrared radiation (700-1000 nm, NIR) were measured in the understory beneath the canopy (PARt and NIRt) and above the canopy (PARi and NIRi) of a Japanese cool-temperate deciduous broad-leaved forest during the snow-free period (May to November). The integration of spectral radiation for NIR and that for PAR, and the daily integrations of instantaneous NIR and PAR, reduced the noises from the optical difference in spectrum and from canopy structure heterogeneity, sky condition and solar elevation. PARi/PARt was linearly related to NIRt/PARt (R2 = 0.96). The effect of cloudiness was negligible, because the fluctuation of NIRi/PARi was quite small regardless of season and weather conditions compared with the range of NIRt/PARt in the forest. The ratio of NIRt/PARt beneath the canopy was log-linearly related to the in situ leaf area index (LAI) with a wide range from 0 to 5.25 (R2 = 0.97). We conclude that seasonal changes in fAPAR (= 1 - PARt/PARi) and LAI of a canopy can be estimated with high accuracy by transmitted NIRt and PARt beneath the canopy.",
author = "Atsushi Kume and Nasahara, {Kenlo N.} and Shin Nagai and Hiroyuki Muraoka",
year = "2011",
month = "1",
day = "1",
doi = "10.1007/s10265-010-0346-1",
language = "English",
volume = "124",
pages = "99--106",
journal = "Journal of Plant Research",
issn = "0918-9440",
publisher = "Springer Japan",
number = "1",

}

TY - JOUR

T1 - The ratio of transmitted near-infrared radiation to photosynthetically active radiation (PAR) increases in proportion to the adsorbed PAR in the canopy

AU - Kume, Atsushi

AU - Nasahara, Kenlo N.

AU - Nagai, Shin

AU - Muraoka, Hiroyuki

PY - 2011/1/1

Y1 - 2011/1/1

N2 - The daily total photosynthetically active radiation (400-700 nm, PAR) and near-infrared radiation (700-1000 nm, NIR) were measured in the understory beneath the canopy (PARt and NIRt) and above the canopy (PARi and NIRi) of a Japanese cool-temperate deciduous broad-leaved forest during the snow-free period (May to November). The integration of spectral radiation for NIR and that for PAR, and the daily integrations of instantaneous NIR and PAR, reduced the noises from the optical difference in spectrum and from canopy structure heterogeneity, sky condition and solar elevation. PARi/PARt was linearly related to NIRt/PARt (R2 = 0.96). The effect of cloudiness was negligible, because the fluctuation of NIRi/PARi was quite small regardless of season and weather conditions compared with the range of NIRt/PARt in the forest. The ratio of NIRt/PARt beneath the canopy was log-linearly related to the in situ leaf area index (LAI) with a wide range from 0 to 5.25 (R2 = 0.97). We conclude that seasonal changes in fAPAR (= 1 - PARt/PARi) and LAI of a canopy can be estimated with high accuracy by transmitted NIRt and PARt beneath the canopy.

AB - The daily total photosynthetically active radiation (400-700 nm, PAR) and near-infrared radiation (700-1000 nm, NIR) were measured in the understory beneath the canopy (PARt and NIRt) and above the canopy (PARi and NIRi) of a Japanese cool-temperate deciduous broad-leaved forest during the snow-free period (May to November). The integration of spectral radiation for NIR and that for PAR, and the daily integrations of instantaneous NIR and PAR, reduced the noises from the optical difference in spectrum and from canopy structure heterogeneity, sky condition and solar elevation. PARi/PARt was linearly related to NIRt/PARt (R2 = 0.96). The effect of cloudiness was negligible, because the fluctuation of NIRi/PARi was quite small regardless of season and weather conditions compared with the range of NIRt/PARt in the forest. The ratio of NIRt/PARt beneath the canopy was log-linearly related to the in situ leaf area index (LAI) with a wide range from 0 to 5.25 (R2 = 0.97). We conclude that seasonal changes in fAPAR (= 1 - PARt/PARi) and LAI of a canopy can be estimated with high accuracy by transmitted NIRt and PARt beneath the canopy.

UR - http://www.scopus.com/inward/record.url?scp=78650510653&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=78650510653&partnerID=8YFLogxK

U2 - 10.1007/s10265-010-0346-1

DO - 10.1007/s10265-010-0346-1

M3 - Article

C2 - 20428920

AN - SCOPUS:78650510653

VL - 124

SP - 99

EP - 106

JO - Journal of Plant Research

JF - Journal of Plant Research

SN - 0918-9440

IS - 1

ER -