What Are The Optimal Spectral And Spatial Resolution Requirements For Sentinel-2 Satellite Imagery To Accurately Detect And Quantify The Extent Of Mangrove Forest Blue Carbon Stocks In A Mixed-species, Tidally-influenced Wetland Environment With A Complex Matrix Of Water, Mudflats, And Vegetated Habitats?

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To accurately detect and quantify mangrove blue carbon stocks using Sentinel-2 satellite imagery in a complex, tidally-influenced wetland, the following approach is recommended:

Spectral Resolution:

  • Multispectral Bands: Utilize Sentinel-2's 13 spectral bands, focusing on the visible (B2 blue, B3 green, B4 red), near-infrared (B8), and short-wave infrared (B11, B12) bands. These are crucial for distinguishing mangroves from other vegetation and habitats.
  • Red-Edge Bands: Incorporate B5, B6, and B7 for assessing vegetation health and chlorophyll content, which are indicators of mangrove productivity and carbon stock.

Spatial Resolution:

  • 10m Resolution: The highest spatial resolution available from Sentinel-2 is optimal for capturing the fragmented and narrow structures of mangrove environments, providing sufficient detail for accurate mapping.

Temporal Considerations:

  • Tidal Timing: Ensure images are captured during optimal tidal phases to minimize water cover and maximize vegetation visibility.
  • Revisit Time: Leverage Sentinel-2's 5-day revisit capability to acquire cloud-free images and monitor temporal changes, though single assessments may suffice depending on the study.

Processing Techniques:

  • Atmospheric Correction: Apply Sen2Cor for accurate surface reflectance, essential for reliable spectral analysis.
  • Classification Methods: Use advanced techniques such as object-based image analysis and machine learning algorithms to handle the complex habitat matrix, integrating field data for validation.

Additional Considerations:

  • Data Integration: Consider combining Sentinel-2 data with other sources, like Sentinel-1 SAR, for enhanced accuracy, though Sentinel-2 alone is sufficient for many applications.
  • Time-Series Analysis: Use multi-temporal data to monitor changes and understand carbon sequestration dynamics, though seasonal variations may require careful planning.

Conclusion:

Sentinel-2's 10m spatial resolution with its comprehensive spectral bands is well-suited for assessing mangrove blue carbon stocks. Effective use of tidal timing, atmospheric correction, and advanced classification methods will enhance accuracy, supported by field validation for reliable results.