Temporal survey of P- A nd L-band polarimetric backscatter in boreal forests
Artikel i vetenskaplig tidskrift, 2018

Environmental conditions and seasonal variations affect the backscattered radar signal from a forest. This potentially causes errors in a biomass retrieval scheme using data from the synthetic aperture radar (SAR) data. A better understanding of these effects and the electromagnetic scattering mechanisms in forests is required to improve biomass estimation algorithms for current and upcoming P- A nd L-band SAR missions. In this paper, temporal changes in HH-, VV-, and HV-polarized P- A nd L-band radar backscatter and temporal coherence from a boreal forest site are analyzed in relation to environmental parameters. The radar data were collected from a stand of mature Norway spruce ( Picea abies (L.) Karst.) with an above-ground biomass of approximately 250 tons/ha at intervals of 5 min from January to August 2017 using the BorealScat tower-based scatterometer. It was observed that subzero temperatures during the winters cause large variations (4 to 10 dB) in P- A nd L-band backscatter, for which the HH/VV backscatter ratio offered some mitigation. High wind speeds were also seen to cause deviations in the average backscatter at P-band due to decreased double-bounce scattering. Severe temporal decorrelation was observed at L-band over timescales of days or more, whereas the P-band temporal coherence remained high (> 0.9) for at least a month neglecting windy periods. Temporal coherence at P-band was highest during night times when wind speeds are low.

boreal forest

Backscatter

P-band

L-band

temporal coherence

time series

synthetic aperture radar (SAR)

Författare

Albert Monteith

Chalmers, Rymd-, geo- och miljövetenskap, Mikrovågs- och optisk fjärranalys

Lars Ulander

Totalförsvarets forskningsinstitut (FOI)

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

1939-1404 (ISSN)

Vol. 11 10 3564-3577 8335779

Ämneskategorier

Skogsvetenskap

Naturgeografi

Klimatforskning

DOI

10.1109/JSTARS.2018.2814825

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Senast uppdaterat

2018-11-15