https://www.npgo.org/ 2026-08-31 monthly 1.0 https://www.npgo.org/npgo-social-card.png North Pacific Gyre Oscillation (NPGO) index, 1950-2025 https://www.npgo.org/img/NPGO_main_new.png NPGO sea level anomaly pattern with CalCOFI and Line P observations https://www.npgo.org/data/NPGO_index.png NPGO index time series, 1950-2025 https://www.npgo.org/data/NPGO.txt 2026-08-31 monthly 0.9