干旱区生态环境知识资源中心(Arid): Temporal decorrelation of C-band radar data over wheat in a semi-arid area using sub-daily tower-based observations

Arid

DOI	10.1016/j.rse.2024.114059
	Temporal decorrelation of C-band radar data over wheat in a semi-arid area using sub-daily tower-based observations
	Ouaadi, Nadia; Jarlan, Lionel; Villard, Ludovic; Chakir, Adnane; Khabba, Said; Fanise, Pascal; Kasbani, Mohamed; Rafi, Zoubair; Le Dantec, Valerie; Ezzahar, Jamal; Frison, Pierre-Louis
通讯作者	Ouaadi, N
来源期刊	REMOTE SENSING OF ENVIRONMENT
ISSN	0034-4257
EISSN	1879-0704
出版年	2024
卷号	304
英文摘要	Recent studies have shown that radar temporal coherence over tropical and boreal forests undergoes a diurnal cycle as a result of a combined effect of the wind-induced motion of scatterers and of the change and displacement of water within the plant in response to the transpiration process. Within this context, the objective of this paper is to investigate, for the first time, the diurnal cycle of temporal coherence over wheat crops in relation to its development and physiological functioning throughout the agricultural season. A ground-based experiment was installed in Morocco, targeting a wheat field during the 2020 agricultural season. The radar system, essentially based on a Vector Network Analyzer (VNA) connected to 6C -band antennas installed at the top of a 20 m tower, has enabled quad-polarimetric acquisitions every 15 min. In parallel, evapotranspiration, soil moisture and meteorological variables are automatically measured in addition to above-ground biomass and vegetation water content collected during field campaigns. The results show that the temporal coherence with a 15 min baseline follows a marked diurnal cycle characterized by variable amplitude according to the phenological stage, with high values during the night, a significant morning drop to reach the lowest values in the late afternoon followed by an increase to recover the high nighttime values. The rate of the drop at dawn is shown to be related to the increase of evapotranspiration (r = 0.80 at VV polarization) when the wheat is covering the soil and the transpiration dominate the evapotranspiration process. This supports the assumption of a physiological effect related to water movement entailing a decorrelation. By contrast, the daily minimum of temporal coherence occurring in the late afternoon correlates well to the daily maximum of wind (r = 0.7). Interestingly enough, the amplitude of the diurnal cycle exhibit a marked seasonal evolution characterized by an increase of 85% from tillering to maturity in relation to the wheat development. At the early start of the season when the soil is almost bare, irrigation events impact slightly the diurnal cycle of temporal coherence. Likewise, it is shown that the presence of dew in the early morning has led to a decrease of the decorrelation rate. Temporal coherence dynamic has also been investigated for longer baselines up to 22 days. Results indicate a stronger decorrelation than what has been observed on tropical and boreal forests by previous studies with values below 0.4 for baselines above 2 days. Taken together, the results of this work demonstrate the unique potential of sub-daily Cband data for monitoring crop water status by future geostationary radar missions such as Hydroterra.
英文关键词	Temporal coherence C-band Diurnal cycle Seasonal cycle Evapotranspiration Irrigation Dew Wheat Phenological stages Semi-arid region
类型	Article
语种	英语
开放获取类型	hybrid
收录类别	SCI-E
WOS记录号	WOS:001196984200001
WOS关键词	INTERFEROMETRIC COHERENCE ; SAP FLOW ; IN-SITU ; WATER ; CALIBRATION ; TEMPERATURE ; BACKSCATTER ; PARAMETERS ; SCATTERING ; MODEL
WOS类目	Environmental Sciences ; Remote Sensing ; Imaging Science & Photographic Technology
WOS研究方向	Environmental Sciences & Ecology ; Remote Sensing ; Imaging Science & Photographic Technology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/405330
推荐引用方式 GB/T 7714	Ouaadi, Nadia,Jarlan, Lionel,Villard, Ludovic,et al. Temporal decorrelation of C-band radar data over wheat in a semi-arid area using sub-daily tower-based observations[J],2024,304.
APA	Ouaadi, Nadia.,Jarlan, Lionel.,Villard, Ludovic.,Chakir, Adnane.,Khabba, Said.,...&Frison, Pierre-Louis.(2024).Temporal decorrelation of C-band radar data over wheat in a semi-arid area using sub-daily tower-based observations.REMOTE SENSING OF ENVIRONMENT,304.
MLA	Ouaadi, Nadia,et al."Temporal decorrelation of C-band radar data over wheat in a semi-arid area using sub-daily tower-based observations".REMOTE SENSING OF ENVIRONMENT 304(2024).