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Snow Water Equivalent of Dry Snow Measured by Differential Interferometry

Leinss, Silvan and Wiesmann, A. and Lemmetyinen, Juha and Hajnsek, Irena (2015) Snow Water Equivalent of Dry Snow Measured by Differential Interferometry. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 8 (8), 3773 -3790. IEEE - Institute of Electrical and Electronics Engineers. doi: 10.1109/JSTARS.2015.2432031. ISSN 1939-1404.

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Official URL: http://ieeexplore.ieee.org/


Large scale mapping of snow water equivalent (SWE) is a long-lasting request in many scientific and economical fields. Active and passive microwave remote sensing methods are explored, as local methods cannot be generalized due to the spatial inhomogeneity of the snow pack. Microwaves interact with snow by absorption, scattering, and refraction. For dry snow of a few meters depth and frequencies below 20 GHz, absorption and scattering in the snow volume are negligible compared with the backscattered energy from the underlying ground. The signal delay caused by refraction can be measured with differential radar interferometry, but phase wrapping errors and temporal decorrelation must be considered. We demonstrate that large ΔSWE can be accurately determined from dense time series of differential interferograms at Xand Ku-band by temporal integration. Lost phase cycles are reconstructed with a two-frequency approach. Temporal decorrelation is minimized by a temporal resolution of 4 h. A linear function between ΔSWE and phase difference is derived, which deviates only a few percent from the exact solution and which depends negligibly on snow density and stratigraphy. ΔSWE retrieved from observations of the SnowScat instrument (SSI) were validated against observed SWE from different reference instruments, installed at a test site near the town of Sodankylä, Finland. An accuracy below ±6 mm SWE was achieved at frequencies of 10 and 16 GHz for up to 200 mm of ΔSWE. An exceptionally high temporal coherence was observed for up to 30 days for dry snow, whereas for wet snow it decayed within hours.

Item URL in elib:https://elib.dlr.de/100787/
Document Type:Article
Title:Snow Water Equivalent of Dry Snow Measured by Differential Interferometry
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Lemmetyinen, JuhaFMI, Arctic Research, Sodankylä, FinlandUNSPECIFIEDUNSPECIFIED
Date:April 2015
Journal or Publication Title:IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:3773 -3790
Publisher:IEEE - Institute of Electrical and Electronics Engineers
Series Name:IEEE Xplore
Keywords:snow water equivalent (SWE), Microwaves, differential radar interferometry
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Earth Observation
DLR - Research theme (Project):R - Vorhaben Multi-dimensionale SAR-Auswertung (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Microwaves and Radar Institute > Radar Concepts
Deposited By: Radzuweit, Sibylle
Deposited On:11 Dec 2015 09:28
Last Modified:23 Jul 2022 13:44

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