| 半干旱榆中地区最小有效降水量及降水转化率的研究 |
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| 引用本文： | 王文玉,张强,阳伏林.半干旱榆中地区最小有效降水量及降水转化率的研究[J].气象学报,2013,71(5):952-961. |
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| 作者姓名： | 王文玉 张强 阳伏林 |
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| 作者单位： | 兰州大学大气科学学院, 兰州, 730000;中国气象局兰州干旱气象研究所, 甘肃省干旱气候变化与减灾重点实验室, 中国气象局干旱气候变化与减灾重点开放 实验室, 兰州, 730020;兰州大学大气科学学院, 兰州, 730000;中国气象局兰州干旱气象研究所, 甘肃省干旱气候变化与减灾重点实验室, 中国气象局干旱气候变化与减灾重点开放 实验室, 兰州, 730020;甘肃省气象局, 兰州, 730020;中国气象局兰州干旱气象研究所, 甘肃省干旱气候变化与减灾重点实验室, 中国气象局干旱气候变化与减灾重点开放 实验室, 兰州, 730020;甘肃省气象局, 兰州, 730020 |
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| 基金项目： | 国家自然科学基金重点项目“黄土高原陆面过程观测与试验研究”(40830957);国家公益性行业(气象)科研专项“西北地区旱作农业对气候变暖的响应特征及其预警和应对技术研究”(GYHY200806021);中国气象局兰州干旱气象研究所科研项目(KYS2012BSKY01)。 |
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| 摘 要： | 有效降水对于土壤水分的补充和农作物的生长来说是一个很重要的概念。通常认为大于5 mm的降水即为有效降水。但是有效降水的影响因素很多,在不同的地理环境和气候背景条件下,最小有效降水量也会有所不同。利用2006年6月—2011年3月兰州大学半干旱气候与环境观测站资料,从土壤湿度变化的角度出发,根据有效降水的定义,对甘肃榆中地区的最小有效降水量做了初步研究。通过分析该地区不同季节、温度和植被条件下不同土壤深度最小有效降水量,发现5、10、20 cm土壤层的最小有效降水量分别为4、5、8 mm。季节分布上,各层土壤最小有效降水量均为夏季最高,春季和秋季值较为接近。高温年的最小有效降水量高于低温年的值,生长季高于非生长季。在降水超过最小有效降水量并且量级较小时,随着降水量的增大,土壤湿度增量呈指数形式增大,这时降水的转化率也较高；而当降水达到一定量级时,超过了土壤的入渗率,水分以径流的形式损失,土壤湿度增量的变化率减小,降水的转化率也趋于一定值。0—20 cm土壤层降水转化率达到70%。
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| 关 键 词： | 陆面最小有效降水量 土壤湿度 降水转化率 |
| 收稿时间： | 2013/1/23 0:00:00 |
| 修稿时间： | 6/9/2013 12:00:00 AM |
Study of the minimum available precipitation and the precipitation conversion rate in the semi-arid Yuzhong region |
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| WANG Wenyu,ZHANG Qiang and YANG Fulin.Study of the minimum available precipitation and the precipitation conversion rate in the semi-arid Yuzhong region[J].Acta Meteorologica Sinica,2013,71(5):952-961. |
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| Authors: | WANG Wenyu ZHANG Qiang and YANG Fulin |
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| Institution: | College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China;Institute of Arid Meteorology, CMA; Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province; Key Open Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Lanzhou 730020, China;College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China;Institute of Arid Meteorology, CMA; Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province; Key Open Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Lanzhou 730020, China;Gansu Provincial Meteorological Bureau, Lanzhou 730020, China;Institute of Arid Meteorology, CMA; Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province; Key Open Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Lanzhou 730020, China;Gansu Provincial Meteorological Bureau, Lanzhou 730020, China |
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| Abstract: | Available precipitation is a very important concept for the complement of soil moisture and crop growth. Generally rainfall greater than 5 mm is considered as available precipitation. There are many factors influencing available precipitation. In different regions and weather conditions, the minimum available precipitation will be different. From the point of view of soil moisture change and according to the definition of available precipitation, a preliminary study of the minimum available precipitation in Yuzhong was made, with the data measured during June 2006 to March 2011 provided by the Semi-Arid Climate Observatory and Laboratory. By analyzing the minimum available precipitation of different soil depths in the different seasons, under different temperature and vegetation conditions, we found that the minimum available precipitation of 5 cm, 10 cm, 20 cm soil layers are 4 mm, 5 mm, 8 mm. As for the seasonal distribution, the minimum available precipitations in summer are the highest of all soil layers. In spring and autumn the values are closer to each other. In the warmer year the minimum available precipitation is higher than that of the low temperature year; in the growing season it is higher than the value of the non-growing season. With the increase of the amount of precipitation, soil moisture increment exponentially increases when precipitation is larger than the minimum available precipitation and of small magnitude. Then precipitation conversion is higher. And when precipitation reaches a certain level, at which the rainfall intensity is larger than the soil infiltration rate, the water loses in the form of runoff, the rate of the soil moisture increment reduces, and the conversion rate of the precipitation tends to a constant value. The conversion rate of precipitation in 0-20 cm soil layer reaches 70%. |
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| Keywords: | Minimum available precipitation on land surface Soil moisture Precipitation conversion rate |
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