The opposite evolvement of climate-productivity among sub-districts on Loess Plateau in China

By investigating the distribution and change of climate-productivity on Loess Plateau during recent 40 years, it was shown that the climate-productivity evolved with opposite phase between north and south, as well as east and west. As for the change of north and south, the turning point was in 1984, the climate-productivity decreased remarkably in the south but rose in the north. As for the change of east and west, the turning point was in 1982, the climate-productivity tended to decrease in the east but increase in the west. By using wavelet analysis, the 2~4 years and 8 years variation period was identified on precipitation, and the 4 years period was most outstanding.