Development of a Spatiotemporal Estimation Method for Rice Plant Height Using Pattern Matching Based on Time-Series Satellite-Derived Vegetation Indices and In Situ Measurements

Abstract

Rice plant height is a key indicator of crop growth and phenology, yet continuous daily estimation remains challenging under limited field observations. This study proposes an interpretable Bayesian LUT-based framework to estimate rice plant height from time-series, satellite-derived GCVI, and sparse in situ measurements. Daily plant height was estimated as a posterior-weighted ensemble of multiple LUT-derived heights, together with uncertainty reflecting ambiguity among plausible growth trajectories. Applied to rice paddies in Ryugasaki City, Japan, using Harmonized Landsat–Sentinel-2 data from the 2025 growing season, the method achieved R2=0.85 and RMSE = 7.08 cm on the validation dataset, outperforming simple baseline approaches. The estimated daily height time series also enabled evaluation of the timing at which plant height reached 70 cm, revealing clear spatial variability among fields and an associated uncertainty of approximately 10 days. Although this threshold was discussed with reference to previous studies on L-band SAR sensitivity, the present study relied solely on optical observations. Overall, the proposed framework provides a data-efficient and explainable approach for daily, spatially explicit rice growth monitoring, while current limitations include the single-region, single-year LUT construction and the simplified statistical assumptions used in the Bayesian weighting framework.

Plant phenotyping relevance

衛星由来時系列データからイネの草丈を推定する手法を開発し、検証データで性能評価しているため、植物フェノタイピング手法が中心です。

Code and data availability

The supplied blocks describe field-measured rice plant heights, HLS/GCVI time series, and a Bayesian LUT workflow implemented in Python, but contain no data availability statement, deposited dataset, or author code repository with a public URL. The HLS data are obtained via Google Earth Engine and the HRLULC map is a J

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