陕甘宁接壤区气候暖干化及其生态环境意义

应用陕甘宁接壤区1951-2000年气温、降水及1956-2000年陕甘宁接壤区 7条主要河流径流量实测记录,在实地调研的基础上对气象数据和水文数据分析后得出结论,陕甘宁接壤区近年来气候呈现暖干化趋势,全区增温线性倾向值为 0．194℃／10 a,高于全球近百年的趋势（0．05℃／10 a）,区内增温趋势强弱差异显著。陕甘宁接壤区气候变干表现在 2个方面：①年降水量减少;②地表径流量减少。降水线性倾向值平均为－1．0759 mm／a,地表径流总量1956-2000年减少速率为 0．4844 m³／a。陕甘宁接壤区生态环境在暖干化的气候背景下继续恶化,生态贫水化严重,水土流失加剧,沙漠扩大。

STUDY ON THE TENDENCY OF CLIMATE CHANGE AND IT'S EFFECT ON ECOLOGICAL ENVIRONMENT IN THE SHANNXI-GANSU-NINGXIA BORDER AREA

    Global climate warming is a truth in 20 century. The middle latitude area is sensitive to the climate change. Shaanxi-Gansu-Ningxia border area is in the middle latitude area, including Yulin district and Yan'an district in Shannxi province, Xihaigu district in Ningxia province, Qingyang district in Gansu province. There is 13.8×10⁴ km² and 1 002×10⁴ population. The density of population there is 73 km², much more higher than that of the limit in similar area by the United Nations which is 20 km². Shaanxi-Gansu-Ningxia border area is the hill and gully area in the middle of Loss Plateau where the climate is changeful and the soil erosion is the most serious and the ecological environment is the most fragile.
    Based on the atmospheric temperature and precipitation records of the Shaanxi-Gansu-Ningxia border area from 1951 to 2000,made an on-the-spot investigation. Analyzed the temperature, precipitation and surface runoff records, reach the conclusion that the characteristics of climate change in the Shaanxi-Gansu-Ningxia border area is becoming warmer and drier.
    The linear tendency of warming is 0.194℃/10a,higher than that of the global(0.05℃/10a) and lower than other place's in China. The maximum linear tendency of warming in Shaanxi-Gansu-Ningxia border area is 0.87℃/10a in Dingbian country, it’s far higher than that of the Sanjiang plain which is the maximum in China. The lowest linear tendency of warming in Shaanxi-Gansu-Ningxia border area is 0.0778℃/10a in Jingyuan country. The average value of linear tendency of warming in Shaanxi-Gansu-Ningxia border area is 0.194℃/10a.
    Shaanxi-Gansu-Ningxia border area is warming and drying displayed in two aspect, one is the diminution in precipitation, the other is reduction in surface runoff. The linear tendency of annual rainfall is different with district and the mean linear tendency of annual rainfall is -1.0759mm/a. In 50 years, the annual precipitation reduced 54 mm. The surface runoff reduced at the rate of 0.4844 m³/a from 1956 to 2000. 
    The ecological environment in Shaanxi-Gansu-Ningxia border area is going aggravating under the change of climate. The main aggravation of ecological environment represented by ecological deficient of water resource, soil erosion intensify and extension of desertification.