The field survey for the elucidation of the mechanism and the control of the drought that occurs frequently in the agricultural zone of the yellow river basin in recent years

在中国黄河流域的农业区，水资源短缺从1972年开始频繁发生，一直持续到1999年。我们明确了这一机制，并提出了一种合适的农业形式。对黄河流域水资源进行了评价。基于GMS的地表温度和反照率模型通过多元线性回归分析，假设了14个点的降水。通过该模型得出黄河流域降水不存在下降趋势的结论。利用卫星资料建立了太阳辐射和净辐射模型，并应用于2000年6月至2002年12月的神木和玉城地区。太阳辐射的分布与观测所得的气候图相似。我们还建立了一个蒸发蒸腾模型，并应用于安塞。该模型显示，农作物缺水的天数为151天。为了保持足够的含水量，灌溉水量为239mm。下游流域的用水受到上游和中游流域流出的影响，尽管做出了有效利用水资源的努力，但情况仍不可预测。利用1981—2000年的卫星资料和观测资料，研究了黄河下游流域植被在干枯期的变化，发现了径流与NDVI的相关关系。它来自于黄河对秋季灌溉的吸收。

In the agricultural area in the Yellow River basin in China, a water shortage occurred frequently in 1972 and continued until 1999. We clarified this mechanism and proposed a suitable agricultural form.Evaluation of water resources of the Yellow River basin was performed. The model with surface temperature and albedo by GMS presumes the precipitation of 14 points by multiple linear regression analysis. From this model, we concluded that the precipitation of the Yellow River basin does not have a downward tendency.We developed a model for the solar and net radiation by satellite data and applied to Shenmu and Yucheng form June 2000 to December 2002. The distribution of solar radiation is similar to the climate map by observation. We also developed a model for evapo-transpiration and applied to Ansai. The model showed there were 151 days of water shortage for crops. To keep sufficient water content, irrigation with 239mm of water was needed.The water use in the lower basin is affected the outflow from the upper and the middle basin and although the effort to effective water use was made, the situation is still unpredictable. We also investigated the change of the vegetation in the lower basin of Yellow River during the periods of dry-up of the river by satellite data and observational data in 1981-2000 and found the correlation between the water flow rate and NDVI. It came from the uptake of water from the Yellow River to irrigate the autumn.