WELLINGTON/SYDNEY: The Australian and New Zealand dollars popped higher against the US dollar on Thursday, after strong Chinese trade data boded well for the countries' exports and commodity prices. Both currencies also scaled fresh four-year peaks versus a meek yen.   Beijing reported exports in December jumped 14.1 percent, from a year earlier, far outstripping forecasts of a 4 percent increase. Imports were up 6 percent, handily beating market forecasts for a 3 percent rise and quickening from zero growth in November.   The upbeat reading is good news for Australia as China is Australia's top export market as well as a key driver of prices for commodities.   "With iron ore prices at $158.50 a tonne and Chinese trade balance looking good, it's saying that things are picking up in China and that supports the Aussie dollar," said Matthew Johnson, a rate strategist at UBS.   The Australian dollar jumped around half a cent on the data ...