使用秩次集对方法预测地下水位动态变化

Application of Rank Set Pair Analysis Method to Predicting Groundwater Dynamics

为了说明秩次集对分析方法在预测地下水位动态变化中的能力以及不同的历史集合容量和后续值个数对该方法预测结果的影响,结合甘肃省白银市景泰县2处地下水位测站的长序列观测资料,研究了不同的历集合容量对单后续值秩次集对分析方法和多后续值秩次集对分析方法预测效果的影响。首先,取不同的历史集合容量T(3、4、5、6、8、10、12、15),在单后续值的情况下分析了不同的历史集合容量对预测误差的影响。然后,分12种情形研究了在历史集合容量T固定的情形下不同的后续值个数n对预测精度的影响。研究结果发现,秩次集对分析方法在预测该地区地下水位动态变化时,若历史集合容量T小于8,误差基本保持稳定,但当T大于8,则误差会急剧增加;秩次集对方法在预测地下水位一个短时间序列内的变化精度较高,但是对地下水位动态变化长序列的模拟能力较差;秩次集对方法在预测时趋势误差累积相当严重;相对于模拟单一后续值,应用秩次集对分析方法预测n(n>1)个后续值可以较有效减缓预测时趋势误差的累积,但用于长序列预测精度仍然不高。

In order to investigate the performance of rank set pair analysis( RSPA) in predicting groundwater dynamics and its response to the abovementioned two parameters,a series of scenarios were carried out by using the long-term groundwater table records in the Jingtai site of the Baiyin county,Gansu province. First,the size of historical set T was assigned as one of eight different values ranging 3 to 15 respectively. The effect of historical set size on prediction error was studied,in the case of single subsequent value. Then,by keeping historical set size T fixed,the influence of number of subsequent value n on prediction error was investigated. The study revealed that when historical set size was less than 8,the error was steady and acceptable and when the size became greater than 8,the error might remarkably increase. RSPA performed well in predication of groundwater dynamics within a short term,however,poorly in predicting a long-term dynamics of groundwater. RSPA had serious disadvantage in error accumulation occurred in every step. In comparison with single subsequence value,the multi-subsequence value could make the accumulation of error of RSPA increases slowly,yet,it still could not fulfill the requirement of predicting a long-term groundwater dynamics.