投影寻踪技术在大连市农业干旱脆弱性评价中的应用

Application of the Projection Pursuit Technique in Assessment of Agricultural Drought Vulnerability in Dalian

本文引入投影降维的思想,将投影寻踪技术运用到农业干旱脆弱性评价中,建立了大连市农业干旱脆弱性评价的投影寻踪模型。选取人口密度、农业产值比重、水田面积比重、降水量、播种面积比、农业人口比重、人均粮食产量、灌溉指数、农民人均纯收入和单位面积农用化肥量10个评价指标构建农业干旱脆弱性评价指标体系,应用投影寻踪模型对评价样本的各指标因素进行线性投影,把最优投影方向所对应的投影特征量作为评价依据,对大连市7个区(市或县)2000年-2007年的农业干旱脆弱性进行评价。结果表明,7个区(市或县)8年农业干旱脆弱性平均值由大到小排序依次为:庄河市>普兰店市>瓦房店市>金州区>旅顺口区>长海县>甘井子区,大连市北部农业干旱脆弱性高于中部和南部。投影寻踪模型能较好地从整体上对农业干旱进行时空评价,为涉及多因素的农业干旱脆弱性评价提供了一条新思路。

Drought can directly affect agricultural output and food shortages. Its continuous accumulation can result in significant land degradation, water resources depletion, and environmental damage, which can restrict the sustainable development of agriculture. The status of agricultural production is prominent in Dalian. It often suffers from drought disaster, which has restrained agricultural development in recent years. Unraveling characteristics of agricultural drought of Dalian is therefore critical. The authors synthetically considered mechanisms of various interactions of agricultural drought, introduced reduced-order thoughts of projection, and built an agricultural drought model by the Projection Pursuit Technique to evaluate agricultural drought vulnerability of Dalian. A vulnerability evaluation index system was built, including population density, agricultural output value proportion, wet area proportion, precipitation, sowing area ratio, the agricultural population proportion, food production per capita, irrigation index, net income of farmer average per capita, and agricultural fertilizer quantity per unit area. We then selected the best projection direction, took characteristic quantities of direction as the mete yard, and evaluated the agricultural drought vulnerability of seven agricultural areas in Dalian based on the panel dataset during the period 2000-2007. Characteristics of variations in spatial-temporal differences of vulnerability assessment were comprehensively analyzed. Then, the zonal map of agricultural drought vulnerability of the study area was drawn. The following conclusions were drawn. The average values of agricultural drought vulnerability assessment in descending order are Zhuanghe City, Pulandian City, Wafangdian City, Jinzhou District, Lvshunkou District, Changhai County and Ganjingzi District. The agricultural drought vulnerability of the north is higher than the south and central Dalian. Results show that the Projection Pursuit Technique can give appropriate assessment of agricultural drought vulnerability which involves multiple factors, and provide a new way for decision-making. In the meanwhile, the developed model seems to be reliable and feasible, and it would be an effective technioue to evaluate a^icultural drought vlllnerahilitv over other regions.