2604.01196 Reanalysis-Era Global Temperature Trend Estimates Diverge by 40% Across Six Products: A Permutation-Based Concordance Audit for 1980-2020
Six global atmospheric reanalysis products -- ERA5, JRA-55, MERRA-2, NCEP-R2, CFSR, and the Twentieth Century Reanalysis (20CR) -- serve as the observational backbone for climate trend attribution, yet their mutual consistency has never been audited at the grid-cell level with formal uncertainty quantification. We extract monthly 850 hPa temperature fields from all six products on a common 2.