Ground movement measured by radar (NISAR, beta)
What it measures. A map of how much the ground surface shifted between two radar passes, derived from the change in the radar signal's phase. It also includes measures of data quality like how well the two passes match.
How it's made. A processed radar product from the NASA-ISRO NISAR mission, made by combining two radar images and projecting the results onto a geographic map grid at about 80-meter spacing. This is an early 'beta' version.
How & where you'd use it. Used to detect ground motion from earthquakes, volcanoes, landslides, and sinking land. As a beta product, it's aimed mainly at researchers testing and evaluating the data.
What's measured
Coverage & cadence
- Time span2025-10-01 → ongoing
- Measured byNISAR (L-SAR, S-SAR)
- Processing levelLevel 2
- Spatial extent-180, -90, 180, 90
- FormatsHDF5, PNG, XML, PDF, CSV, KML, YAML
- StatusACTIVE
What you can do with it
- Track deforestation, fire scars and land-cover change
- Monitor crop and vegetation health (NDVI/EVI)
- Map how built-up vs. green an area is over time
Official description
The NASA-ISRO Synthetic Aperture Radar (NISAR) Geocode Unwrapped Interferogram (GUNW) product is a Level 2 product derived from the Range Doppler Wrapped Interferogram (RIFG) and Range Doppler Unwrapped Interferogram (RUNW) products by geocoding the unwrapped phase and associated data layers (i.e., coherence magnitude, ionospheric phase screen) on a geographical grid at 80 m posting. Geocoding is performed using the orbit of the reference Range Doppler Single Look Complex (RSLC) product and a Digital Elevation Model (DEM) to project the data onto a predefined Universal Transverse Mercator (UTM) or Polar stereographic projection system map grid. The geocoding algorithm uses a bilinear interpolation for interpolating data layers with floating-point data types, Sinc for the complex wrapped interferogram, and nearest-neighbor interpolation for unsigned integer datasets (e.g., connected components mask). The GUNW products also include the wrapped complex interferogram (multilooked at 30 m in range-Doppler coordinates and geocoded at 20 m posting), the unwrapped interferometric phase in radians (80 m posting), the normalized interferometric coherence magnitude (20 m and 80 m posting), connected components mask, and sub-pixel offset layers obtained from incoherent cross-correlation. If a Range Doppler Pixel Offsets (ROFF) product is available for the processed frame, the sub-pixel offset layers included in GUNW are obtained by optimally blending the multi resolution offset layers included in ROFF. The GUNW product includes an ionospheric phase screen layer from the RUNW product and a layer quantifying its uncertainty. In the case of mode transitions where the continuity of spectral bands is impacted, a split spectrum ionospheric phase estimate is derived from the main imaging band frequency A. The estimated ionospheric phase screen is included in the product but not applied to the data layers within GUNW by default. The GUNW product also includes geocoded lookup tables for external phase corrections (e.g., solid Earth tides, hydrostatic and wet tropospheric phases). These phase corrections, when available, are not removed from the interferometric data. The products in this collection are considered Beta products and are intended to enable users to gain familiarity with the parameters and the data formats. Beta products are not intended for use in scientific research.
Get the data
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="NISAR_L2_GUNW_BETA_V1",
version="1",
bounding_box=(-122.5, 37.2, -121.8, 37.9), # your area (W,S,E,N)
temporal=("2024-01-01", "2024-12-31"), # your dates
)
files = earthaccess.open(results) # stream straight from ASFBrowsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.