NASA HLS Project: Harmonized Landsat and Sentinel-2 Surface Reflectance Data

The Harmonized Landsat Sentinel-2 (HLS) project provides consistent surface reflectance and top-of-atmosphere brightness data from the Landsat 8 and Sentinel-2 satellites. It enables global land observations every 2–3 days at 30-meter spatial resolution. The HLSL30 V1.5 product described was decommissioned on January 4, 2022, with users directed to the improved V2 product.

Use Cases

• Monitor land cover change over time based on the 2–3 day global observation frequency.
• Conduct time-series analysis of surface reflectance based on the 'stackable' gridded products from multiple satellites.
• Apply atmospheric correction and cloud masking for clear-sky analysis based on the described processing algorithms.
• Study vegetation or urban development using the 30-meter resolution Nadir BRDF-Adjusted Reflectance (NBAR) data.

Strengths

• Provides data at a consistent 30-meter spatial resolution across satellite sources.
• Combines observations from Landsat 8 and Sentinel-2 for a global revisit frequency of every 2–3 days.
• Products include atmospheric correction, cloud masking, and spectral bandpass adjustment as described.

Limitations

• The described HLSL30 V1.5 product is decommissioned, indicating users must locate and use the newer version.
• Known data gaps exist for version 1.5 between June 1 and June 15, 2021, due to processing errors.
• Images requiring ground control for geometric correction (e.g., very cloudy scenes) are not included in the dataset.

Provenance

Source

NASA's Satellite Needs Working Group (SNWG), using data from NASA/USGS Landsat 8 and ESA Copernicus Sentinel-2.

Collection Method

Satellite imagery processed through atmospheric correction, co-registration, gridding, and normalization algorithms.

Time Range

Temporal coverage is not specified in the provided input.

Freshness

The V1.5 product is no longer current; the last update date for the active dataset is unknown.

Geography

Global land coverage.