q01·intermediate
Is deforestation happening in this area, and what are its effects?
landbiospherecarbon Datasets: 5 5–15 min (small AOI) using cloud-direct access
▶ Find the data for your area
Draw a rectangle to pick your area of interest, then see what NASA data covers it (live, here in your browser) or download a ready-to-run notebook with your AOI pre-filled. The notebook runs in any Python environment — it needs a free Earthdata Login to fetch the data.
Current AOI:
73.5, 15 → 78.5, 20 (Maharashtra Western Ghats)Is deforestation happening in this area, and what are its effects?
What you can answer
- Where forest cover dropped in a specific area over the last N years (NDVI time-series, Hansen annual loss).
- How much biomass was lost in tons of carbon (GEDI L4A footprint biomass averaged inside loss polygons).
- Whether replant / regrowth has occurred (NDVI recovery curve post-event).
- Downstream effects you can begin to test: surface temperature change (ECOSTRESS), evapotranspiration change (ECOSTRESS), soil moisture change (SMAP), precipitation runoff change (IMERG climatology shift).
What you can NOT answer with these datasets alone
- Direct cause (logging vs fire vs disease vs urban expansion) — needs ancillary data.
- Sub-pixel canopy change smaller than ~30m (HLS resolution floor).
- Continuous biomass loss in time — GEDI is footprint-sampled, not continuous swath.
Code template (Python, cloud-direct, ~30 lines)
import earthaccess
import xarray as xr
from pystac_client import Client
earthaccess.login(strategy="netrc")
# 1. Define AOI + time window
aoi = (78.5, 15.0, 73.5, 20.0) # W, S, E, N — Maharashtra Western Ghats
years = (2018, 2024)
# 2. Pull HLS L30 (Landsat) surface reflectance for NDVI
hls_results = earthaccess.search_data(
short_name="HLSL30",
bounding_box=aoi,
temporal=(f"{years[0]}-01-01", f"{years[1]}-12-31"),
cloud_cover=20,
)
# ...open into xarray, compute NDVI = (NIR - Red) / (NIR + Red), tile-mosaic per year
# 3. GEDI L4A footprint biomass intersecting AOI
gedi = earthaccess.search_data(
short_name="GEDI_L4A_AGB_Density_V2_1_2056",
bounding_box=aoi,
temporal=(f"{years[0]}-01-01", f"{years[1]}-12-31"),
)
# ...open HDF5, extract `agbd` and `agbd_se` at footprint coords
# 4. Mask GEDI footprints by HLS-derived loss polygons → compute mean biomass lost
# 5. Plot: NDVI time-series + biomass-density-lost histogram
Expected output
- Map: change in mean annual NDVI between (years[0], years[0]+2) baseline and (years[1]-2, years[1]) recent
- Histogram: biomass density (Mg/ha) of GEDI footprints inside detected loss polygons
- Time-series: pixel-mean NDVI over the AOI, with annotation at known loss events
Caveats
- HLS cloud-cover filter at 20% is aggressive; cloudy regions (Western Ghats monsoon) lose most of June–Sept observations.
- GEDI ended primary mission in March 2023; data from 2019–2023 only for the original era (extended mission resumed 2024 onboard ISS).
- Hansen Global Forest Change is annual, defines “loss” as ≥50% canopy reduction in a 30m pixel — coarser than typical small-holder agroforestry change.
Cross-DAAC composition
This is a 3-DAAC join: LP DAAC (HLS, MODIS) + ORNL DAAC (GEDI). Auth is uniform (Earthdata Login) but the access libraries differ (earthaccess for both, but HDF5 reading for GEDI is more involved than COG-mosaic for HLS). See recipes/r01-three-daac-composition.mdx for the general pattern.
Sources + further reading
- GEDI L4A user guide: https://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=2056
- HLS user guide: https://lpdaac.usgs.gov/products/hlsl30v002/
- Hansen Global Forest Change: https://earthenginepartners.appspot.com/science-2013-global-forest
Datasets used
📚 Problem Finder KB
2 matching entries in the Knowledge Base:
§14 Glossary
HLS HLSS30 / HLSL30 v002
LP DAAC
HLS
Harmonized Landsat & Sentinel-2