Polarization Impact in TanDEM-X Data Over Vertical-Oriented Vegetation: The Paddy-Rice Case Study

Abstract

It has been recently shown that the TanDEM-X mission is capable of tracking the plant growth of rice paddies. The precision of the elevation measure depends on the physical interaction between the synthetic aperture radar (SAR) signal and the canopy. In this letter, this interaction is studied by considering the signal polarization. In particular, the vertical and horizontal wave polarizations are compared, and their performance in the temporal mapping of the crop height is analyzed. The temporal elevation difference analysis shows a monotonically increasing trend within the reproductive stage of the canopy, with maximum height discrepancies between polarizations of about 9 cm. From an operational point of view of InSAR-based vegetation height measurements, this letter demonstrates that the oriented structure of the canopy shall be considered not only in polarimetric InSAR studies but also in the interpretation of bistatic spaceborne interferometric elevation models.

Temporal monitoring of subglacial volcanoes with TanDEM-X — Application to the 2014–2015 eruption within the Bárðarbunga volcanic system, Iceland

“…Various terrain types have been already temporally investigated with TanDEM-X. For instance, changes at glaciers (Rott et al, 2014), growth of agricultural fields Erten, Rossi, & Yuzugullu, 2015), deforestation (Schlund, von Poncet, Hoekman, Kuntz, & Schmullius, 2014) and urban growth studies (Taubenböck et al, 2012) are among successful examples of TanDEM-X temporal data usage. Volcano topographical changes have been also reported with TanDEM-X.…”

Comparison of the TanDEM-X response between vertical and horizontal oriented vegetation

“…4. An inventory of topographic surface changes through the 50 selected agricultural fields: the value of multi-temporal elevation measurements from TanDEM-X HH (a) and VV (b) channels [2]. trend of coherence values are good enough to estimate crop heights, which change depends on crop morphology and polarization.…”

“…However, the strong variability in the location of the phase center through the canopy still has to be considered. In this work, which is detailed in [2], the performance of TanDEM-X mission in canopy height monitoring in the context of polarimetric diversity will be discussed. In addition to temporal HH-polarization analysis in [1], temporal behavior of canopy height estimation from VV-polarized acquisitions will be discussed.…”

A Multi-Year Study on Rice Morphological Parameter Estimation with X-Band Polsar Data

“…In the literature, several SAR data based algorithms have been developed to investigate the phenological evolution of rice fields including their canopy height, growth stage, leaf area index and yields. In SAR based rice monitoring, one way of monitoring the phenological cycle is the use of different SAR data analysis techniques including temporal trend analysis [2,3], interferometric analysis [4,5] and polarimetric interferometry analysis [6,7]. The other approach employs EM models to simulate the polarimetric parameters from plant properties [5,8,9].…”