6 posts
Process large satellite rasters in Python with dask and rioxarray. Open eight full Sentinel-2 scenes lazily, choose a chunk size, inspect the task graph, watch CPU and memory with dask diagnostics, compare peak memory with eager NumPy, time chunk sizes and thread counts, and write a median NDVI GeoTIFF to disk chunk by chunk.
Run a pixel-wise Mann-Kendall trend test and Theil-Sen slope on 24 years of MODIS NDVI in Python. Read MOD13A1 from the Microsoft Planetary Computer, mask it with the QA layer, aggregate to growing-season means, vectorise the tests with xarray.apply_ufunc (checked against pymannkendall), compare the seasonal and modified Mann-Kendall tests, control the false discovery rate across 229,229 pixels, and map greening and browning on China's Loess Plateau.
Detect and quantify methane plumes in Python with NASA's EMIT imaging spectrometer: load open EMIT methane enhancement data from NASA VEDA without a login, separate three Dallas-Fort Worth landfill plumes from the noise, compute the integrated mass enhancement, estimate emission rates with ERA5 winds, and compare them with EPA greenhouse gas inventory figures.
Read ERA5 climate reanalysis in Python with xarray from free, login-free cloud Zarr stores, clip it to the UK, compute area-weighted means and anomalies against 1991–2020, export a Cloud Optimised GeoTIFF and check it against Met Office stations.
Map glacier velocity in Python with NASA's ITS_LIVE Zarr datacubes on AWS, with no login: velocity maps, a flowline traced from the velocity field, 40 years of speed profiles, seasonal and multi-year time series from 80,568 filtered image pairs, and strain rates and flow directions on Jakobshavn Isbræ (Sermeq Kujalleq), Greenland's fastest glacier.
Build a five-year Sentinel-2 NDVI time series in Python: load a lazy dask datacube with odc-stac, mask cloud with SCL, make monthly composites, extract field curves and derive crop phenology.