关键词: 华北地区, 极端气候, 时空变化

Abstract: Using 50-year data from 80 stations in the northern area of China, the extreme temperatures and precipitation indexes were calculated, and the long term trend was also analyzed. The results showed that both maximum and minimum temperatures in North China exhibited a significantly rising trend, with the former being less than the latter in amplitude. After climate abrupt, maximum temperature trend in North China rose significantly with cold night index (TN10) declining obviously, but warm night index（TN90）showing an ascendant trend. After climate mutations, TN10 also showed an obvious decreasing trend. That is, cold day index (TX10) declined, and warm day index (TX90) showed an ascendant trend. In terms of space distribution, maximum temperature large value was located in the west Inner Mogolia and the most areas of Shanxi province, whereas minimum temperature large value was in BeijingTianjinHebei and northeast Shanxi province. The extreme precipitation, rainfall frequency and precipitation intensity in North China tended to decline. Extreme rainfall, extreme precipitation mutation and extreme precipitation intensity showed a striking decreasing trend. Rainfall and rainfall intensity had the same return year of 16 years and 8 years. Strong snow quantity, frequency and intensity showed a clear rising trend. In North China, 〖JP2〗extreme precipitation was roughly distributed from the northwestsoutheast to the north, while in southern North China (e.g. in Hebei province and Shanxi province) extreme precipitation reduced in BeijingTianjin region. Extreme precipitation frequency distribution increased from the east to the west, with a most significant rising trend in the middle area of Shanxi province.

Key words: North China, Extreme climate, Spatial and temporal variation