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Southern China was hit by a severe cold event during January 21–25, 2016, characteristic of a drastic and sudden temperature drop, with new records of low temperatures set in widespread areas. This cold event was dynamically linked to the activity of the Arctic oscillation (AO) whose evolution led the event by about 2 weeks. Different from this short lasting but intense cold event in 2016, another cold event in the 2008 winter lasted much longer and occurred in tandem with freezing precipitation. Their differences in the duration and precipitation are essentially determined by differing behaviours of blocking highs at mid–high latitudes, the India–Burma Trough and the western Pacific subtropical high. The rapid southward invasion of cold air masses during the 2016 event resulted from the rapid decay of the blocking high, which emanated wave energies downstream and likewise lost wave energies to the local mean flow. By contrast, during the 2008 cold event, continuous upstream wave energy dispersion recurrently stimulated disturbances in the blocking domain, which then extracted energies from the mean flow efficiently to survive markedly longer. Moreover, in the 2008 case, the deepening of the India–Burma Trough and the westward extension of the western Pacific subtropical high jointly enhanced the moisture transport, leading to the freezing rain. This favourable configuration for precipitation was absent in the 2016 case, dictating its dry nature accordingly. [ABSTRACT FROM AUTHOR]

The frequency, duration, and intensity of extreme cold events are widely regarded as primary constraints on the upper latitudinal limits of mangroves. Little data are available on the consequences of recovery (or lack thereof) of non-floristic components of mangrove ecosystems after a disturbance caused by cold weather. An unusually severe cold wave occurred in southern China in January 2008. The impact of this cold event and the subsequent recovery of mollusks in a Rhizophora stylosa mangrove forest in southern China were evaluated over a 3-yr study from April 2007 to January 2010. The cold event caused significant mortality of mollusks, which was rapidly followed by an increase in the populations of opportunistic species, and then their subsequent collapse within 6 months. Comparison with data collected in April 2007 (before the cold event) revealed that the density, biomass, and species richness of mollusks decreased by 87.5%, 80.6%, and 56.3%, respectively, except for a transient and compensatory increase in the numbers of benthic mollusks (by 47.5%). Arboreal mollusks were more sensitive to the cold event than benthic species, but both groups showed similar recovery trajectories. After 21 months, the density, biomass, and richness of mollusk species still remained 9.4%, 13.2%, and 26.2% lower than pre-event. Full recovery took more than 24 months. In comparison to mangrove vegetation, mollusks inhabiting mangroves appeared to be more vulnerable to cold events, but also recovered faster. In conclusion, it took more than 2 yr for the species richness of mollusks to recover from the cold event, and the rate of recovery was slower for the arboreal type. [ABSTRACT FROM AUTHOR]