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Vineyard Design, Vine Age, and Floor Management Practices Affect Sentinel-2 NDVI Time Series Analysis of California Vineyards

Baptiste Oger, Mahyar Aboutalebi, Nick Dokoozlian, Luis Sanchez, Maria Mar Alsina
Am J Enol Vitic.  2025  76: 0760023  ; DOI: 10.5344/ajev.2025.25010

Article Figures & Data

Figures

  • Figure 1
    Figure 1

    Trellis system types included in this study.

  • Figure 2
    Figure 2

    Map of the California regions considered in this study, based on American Viticultural Areas.

  • Figure 3
    Figure 3

    Monthly weather data (average temperature and total precipitation) for the four regions considered in this study. Source: alifornia Irrigation Management Information System (CIMIS; https://cimis.water.ca.gov).

  • Figure 4
    Figure 4

    Representation of the three intermediate values used to compute gap score and filter outlier values. A) Gap score is low and equal to d3; B) gap score is high and equal to d1. NDVI, normalized difference vegetation index.

  • Figure 5
    Figure 5

    Density contours of observed normalized difference vegetation index (NDVI) and normalized difference infrared index (NDII) values by trellis type (A) and geographic area (B). NDVI and NDII are median values over a 6-wk time frame from early June to mid-July. Each shape represents the density kernel containing 75% of the vineyards of the group. SP, shoot positioned; VSP, vertical shoot-positioned.

  • Figure 6
    Figure 6

    Normalized difference vegetation index (NDVI) time series averaged by variety, trellis system, and main area in California, from mid-March to mid-October. The 10 main varieties are represented (eight red and two white); other red and white are aggregated. Line width represents the number of time series averaged. SP, shoot positioned; VSP, vertical shoot-positioned.

  • Figure 7
    Figure 7

    Normalized difference vegetation index (NDVI) time series for Cabernet Sauvignon in two California geographic areas (Lodi [A, B] and the North Coast [C, D]) with two specific trellis systems (bilateral cordon [A, B] and vertical shoot-positioned [C, D]). Results are averaged by A) age of the vines, B) weeds and cover crop management, C) row spacing, and D) year.

Tables

  • Table 1

    Overview of the four California winegrape production regions and their corresponding vineyard blocks used for this study. VSP, vertical shoot-positioned; SP, shoot positioned.

    Table 1
  • Table 2

    Growing degree days based on the Winkler index for each California winegrape production region and year examined in this study.

    Table 2
  • Table 3

    Analysis of variance of the factors affecting peak canopy normalized difference vegetation index, based on all available time series. Sum sq, sum of squares; DF, degrees of freedom; AVA, American Viticultural Area.

    Table 3
  • Table 4

    Analysis of variance of the factors affecting peak canopy normalized difference vegetation index in the Central Valley of California. Sum sq, sum of squares; DF, degrees of freedom.

    Table 4
  • Table 5

    Analysis of variance of the factors affecting peak canopy normalized difference vegetation index in coastal California. Sum sq, sum of squares; DF, degrees of freedom.

    Table 5

Additional Files

  • Supplemental Table 1   Average number of images after filtering, per block, for each year and winegrape production region examined in this study.

    Appendix 1  JavaScript code used to extract and filter Sentinel data from Google Earth Engine.
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