Vegetation Height Estimate in Rice Fields Using Single Polarization TanDEM-X Science Phase Data

Seung-Kuk Lee,Joong-Sun Won,Sun Yoon

doi:10.3390/rs10111702

Abstract

This study presents the retrieval of rice paddy height using single polarization (single-pol) interferometric SAR (InSAR) data by means of model-based height inversion without an external DEM. A total of eight TanDEM-X (TDX) scenes were used and the TDX images were; acquired using a large cross-track baseline configuration during the TDX Science Phase (June–August 2015). A single-pol inversion approach for a flooded rice field is proposed and evaluated over the Buan test site in South Korea. A novel approach is adopted for the estimation of the ground (i.e., water level) interferometric phase within a flooded rice paddy from TDX data acquired during a period of early rice growth. It is consequently possible to apply the model-based inversion algorithm to the single-pol InSAR data. Rice height maps during the rice growth cycle presented and validated by field measurements. The results demonstrated the high performance of the inversion with a correlation coefficient of 0.78 and an RMSE of 0.10 m. The proposed methodology will be useful to monitor rice plants and to predict a gross rice yield, along with dual and fully polarimetric interferometric SAR data.

Highlights

Rice is a major food crop and is the most widely consumed for a large part of the world’s human population, especially in Asia
It is important to forecast and estimate annual rice production using a method of rice growth efficiently, over large geographical areas
This paper is aimed at evaluating the retrieval of rice paddy height for a complete growth cycle from post-transplanting to maturation stage by means of single-pol TDX Science Phase data sets

Summary

Introduction

Rice is a major food crop and is the most widely consumed for a large part of the world’s human population, especially in Asia. Asia accounts for more than 90 percent of world rice production and consumption and is important for the food security of approximately half of the world’s population. It is important to forecast and estimate annual rice production using a method of rice growth efficiently, over large geographical areas. The height of vegetation is one key factor used when assessing a potential crop yield. Crop heights have been estimated through field inventory assessments. Airborne lidar is the most accurate method for estimating vegetation height but is limited by its cost over large geographical areas and data volume required to monitor a long-term change (or growth) in the vegetated area of interest

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Results