Several studies have used satellite

Several studies have used satellite data to map
different levels of fire severity present within burned areas. Increasingly,
fire severity has been estimated using a spectral index
called the normalized burn ratio (NBR). This letter assesses the
performance of the NBR against ideal requirements of a spectral
index designed to measure fire severity. According to index
theory, the NBR would be optimal for quantifying fire severity
if the trajectory in spectral feature space caused by different
levels of severity occurred perpendicular to the NBR isolines.
We assess how well NBR meets this condition using reflectance
data sensed before and shortly after fires in the South African
savanna, Australian savanna, Russian Federation boreal forest,
and South American tropical forest. Although previous studies
report high correlation between fire severity measured in the fieldand
satellite-derived NBR, our results do not provide evidence
that the performance of the NBR is optimal in describing fire
severity shortly after fire occurrence. Spectral displacements due
to burning occur in numerous directions relative to the NBR
index isolines, suggesting that the NBR may not be primarily
and consistently sensitive to fire severity. Findings suggest that
the development of the next generation of methods to estimate
fire severity remotely should incorporate knowledge of how fires
of different severity displace the position of prefire vegetation in
multispectral space

Results (Indonesian) 1:

Beberapa studi telah menggunakan data satelit petaberbagai tingkat keparahan api hadir dalam daerah dibakar. Semakin,keparahan api telah diperkirakan menggunakan indeks spektraldisebut dinormalisasi membakar rasio (NBR). Surat ini menilaikinerja NBR terhadap persyaratan ideal spektralIndeks yang dirancang untuk mengukur tingkat keparahan api. Menurut indeksteori, NBR akan optimal untuk kuantifikasi api keparahanJika lintasan di ruang spektral fitur disebabkan oleh berbedatingkat keparahan terjadi tegak lurus NBR isolines.Kami menilai seberapa baik NBR memenuhi kondisi ini menggunakan reflektansidata merasakan sebelum dan setelah kebakaran di Afrika SelatanSavana, Australia Savana, Federasi Rusia hutan boreal,dan hutan tropis Amerika Selatan. Meskipun studi sebelumnyamelaporkan korelasi tinggi antara api keparahan diukur dalam fieldandNBR satelit yang diturunkan, hasil kami tidak memberikan buktikinerja NBR optimal dalam menggambarkan apikeparahan tak lama setelah terjadinya kebakaran. Spektral perpindahan karenapembakaran terjadi dalam berbagai arah relatif terhadap NBRIndeks isolines, menyarankan bahwa NBR tidak mungkin terutamadan secara konsisten sensitif terhadap api keparahan. Temuan menunjukkan bahwapengembangan generasi berikutnya dari metode untuk memperkirakankeparahan api jarak jauh harus memasukkan pengetahuan tentang bagaimana kebakarankeparahan berbeda menggantikan posisi prefire vegetasi diRuang multispectral