Abstract. At high latitudes and altitudes one of the main controls on hydrological biogeochemical processes is breakup freeze-up lake river ice. This study uses 3510 time series from across 678 Northern Hemisphere lakes rivers to explore historical patterns in ice phenology five overlapping periods (1931–1960, 1946–1975, 1961–1990, 1976–2005, 1931–2005). These show that number annual open-water...
