Personal tools
You are here: Home Guanting Basin Climate

Climatic conditions and recent trends

The climate in the Guanting watershed is characterized by two temperate zones: dry and very hot summers and long and cold winter in the north-west, and semi-humid monsoon climate with hot and humid summer and cold and dry winter in the lowlands. The average annual temperature in the region is about 10-13°C. Temperatures amplitudes can be very extreme between winter and summer with temperatures as low as -37°C in winter and as high as 42.6°C in summer. The annual frost free period lasts for 120 (North) to 200 (South). The yearly sunshine time is between 2400-3100 h.

The average annual precipitation is about 450 mm (370-480 mm following Luo et al. (2007) and varies geographically (1990: 348.5 mm of precipitation were recorded on the plains and 1032.7 mm in mountains), seasonally (85% between July and September; 40-70% can fall within 3 days) and annually (several years of droughts are typically followed by several years of floods).

In general, the summer climate in Northern China is shaped by the Monsun, the winter climate depends mainly on the inflow of cold air from Northeast-Siberia. Wet summers are associated with a strong Monsun, dry summer with a weak one. Notably dry summers in the North of China are often accompanied by wet conditions in the South and opposite.

Dust storms are a major problem during spring time in Northern China and the Guanting basin in particular. The frequency is correlated with winter temperatures. Due to the general temperature increase the frequency of dust storms decreased during the recent 50 years   (Qian & Zhu 2001).

 Qian & Zhu (2001) analyzed recent climatic change since 1880 in China and its different regions including Northern China. They found typical reoccurrence intervals for temperature and precipitation. In Northern China, there have been two periods of relatively cool temperatures: at the beginning (until 1910) and at the middle of the last century (1950-1960). Periods of warming were the time between 1920 and 1940 and between 1980 and the end of the last century. The temperature increase amounts to 1.5°C between the recent cooling and warming period. In comparison to the last warming phase, the recent warming episode is about 0.4 to 0.5 °C warmer. The precipitation in Northern China follow a 20 year rhythm. Extraordinary high precipitation occurred between 1940 and 1960. Severe flood events were associated with these higher precipitation levels. Dry periods reflect the temperature and precipitation oscillation. The last dry period lasted from 1920 to 1940. The current dry period started 1990.

For the last 50 years, Tao et al. (2003) found a trend toward agricultural water demands increasing, soil drying and significant changes in soil-moisture variability on the North China Plain and the Northeast China Plain.

(source: Wechsung, project proposal)

Document Actions