0 引 言
1 材料与方法
1.1 研究区概况
1.2 数据来源及预处理
1.3 研究方法
1.3.1 灌区采样点土壤含水量测定
1.3.2 计算温度植被干旱指数(TVDI)
1.3.3 条件植被温度指数(VTCI)
表1 基于不同干旱指数的干旱等级划分标准Table 1 Drought classification criteria based on different drought indices |
干旱等级 | TVDI | VTCI |
---|---|---|
无旱 | [0.00,0.60] | (0.55,1.00] |
轻度干旱 | (0.60,0.71] | (0.41,0.55] |
中度干旱 | (0.71,0.76] | (0.29,0.41] |
重度干旱 | (0.76,0.85] | (0.21,0.29] |
极端干旱 | (0.85,1.00] | [0.00,0.21] |
1.3.4 干旱趋势分析方法
表2 Sen+Mann-Kendall 趋势检验分类标准Table 2 Classification standard of Mann-Kendall trend test |
趋势度β | 统计量|Z| | 趋势分类 |
---|---|---|
β>0 | 2.58<|Z| | 极显著变旱 |
1.96<|Z|≤2.58 | 显著变旱 | |
1.96≥|Z| | 轻微变旱 | |
β<0 | 1.96≥|Z| | 轻微缓解 |
1.96<|Z|≤2.58 | 显著缓解 | |
2.58<|Z| | 极显著缓解 |
1.3.5 ICEEMDAN-ARIMA模型
1.3.6 评价指标
2 结果与分析
2.1 遥感干旱指数适用性评价
2.1.1 遥感监测结果与实际土壤墒情对比
图3 三屯河灌区实测土壤墒情采样点 Fig. 3 Sampling points of measured soil moisture content in Santun river irrigation area |
表3 TVDI/VTCI与0~10 cm实测土壤含水量线性拟合结果Table 3 Linear fitting results of TVDI/VTCI and 0-10 cm measured soil water content |
日期 | TVDI拟合方程 | R 2 | VTCI拟合方程 | R 2 |
---|---|---|---|---|
5月3日 | SM=0.50-0.39TVDI | 0.61 | SM=12.07+55.99VTCI | 0.330 |
6月4日 | SM=0.55-0.44TVDI | 0.58 | SM=24.08-6.72VTCI | 0.016 |
6月20日 | SM=0.50-0.39TVDI | 0.59 | SM=10.66+33.14VTCI | 0.120 |
7月22日 | SM=1.08-1.27TVDI | 0.51 | SM=28.90-10.97VTCI | 0.070 |
8月7日 | SM=0.68-0.63TVDI | 0.66 | SM=9.06+26.70VTCI | 0.280 |
整体 | SM=0.54-0.45TVDI | 0.57 | SM=21.31+2.75VTCI | 0.005 |
2.1.2 TVDI干湿边拟合分析
2.2 新疆三屯河灌区TVDI时空变化特征分析
2.2.1 新疆三屯河灌区TVDI指数分析
2.2.2 TVDI时间变化趋势
2.2.3 TVDI空间变化趋势
图7 2005—2022年新疆三屯河灌区TVDI年际变化率及分布占比Fig. 7 Interannual variation rate and distribution proportion of TVDI in Santun river irrigation area, Xinjiang, from 2005 to 2022 |
2.3 ICEEMDAN-ARIMA组合模型干旱预测
2.3.1 ICEEMDAN-ARIMA建模流程
表4 不同采样点ICEEMDAN-ARIMA组合模型分量定阶Table 4 Component order of ICEEMDAN-ARIMA combination model at different sampling points |
采样点编号 | 分量 | 模型(p, d, q) | AIC+BIC |
---|---|---|---|
S1 | IMF1 | ARIMA(0,0,1) | -116.945 214 3 |
IMF2 | ARIMA(3,0,3) | -205.001 400 2 | |
IMF3 | ARIMA(0,4,2) | -369.452 525 2 | |
RES | ARIMA(0,5,3) | -526.462 120 9 | |
S2 | IMF1 | ARIMA(2,0,0) | -113.691 085 6 |
RES | ARIMA(2,2,0) | -265.102 977 6 | |
S3 | IMF1 | ARIMA(3,0,2) | -152.175 910 4 |
IMF2 | ARIMA(3,0,3) | -287.689 639 4 | |
RES | ARIMA(0,5,3) | -482.443 750 0 | |
S4 | IMF1 | ARIMA(3,0,2) | -147.255 879 8 |
IMF2 | ARIMA(3,0,3) | -301.629 947 7 | |
RES | ARIMA(0,4,3) | -523.041 348 3 | |
S5 | IMF1 | ARIMA(2,0,0) | -103.902 565 0 |
IMF2 | ARIMA(2,3,1) | -309.402 008 9 | |
RES | ARIMA(0,5,1) | -451.759 672 9 | |
S6 | IMF1 | ARIMA(2,0,1) | -120.444 219 0 |
IMF2 | ARIMA(2,4,2) | -322.685 183 7 | |
RES | ARIMA(1,4,3) | -421.850 247 4 | |
S7 | IMF1 | ARIMA(2,0,2) | -156.684 347 8 |
IMF2 | ARIMA(3,0,3) | -273.182 216 9 | |
IMF3 | ARIMA(2,5,2) | -399.505 237 7 | |
RES | ARIMA(0,4,1) | -719.831 411 3 | |
S8 | IMF1 | ARIMA(2,0,3) | -108.192 046 3 |
IMF2 | ARIMA(2,0,1) | -367.734 391 1 | |
RES | ARIMA(0,5,2) | -412.414 395 2 | |
S9 | IMF1 | ARIMA(2,0,1) | -114.222 055 7 |
IMF2 | ARIMA(2,0,3) | -254.384 080 2 | |
IMF3 | ARIMA(0,5,2) | -345.679 598 9 | |
RES | ARIMA(1,5,2) | -592.075 968 4 | |
S10 | IMF1 | ARIMA(2,0,1) | -114.647 198 7 |
IMF2 | ARIMA(2,2,0) | -358.488 825 6 | |
RES | ARIMA(0,5,1) | -455.632 154 1 | |
S11 | IMF1 | ARIMA(2,0,0) | -146.230 360 3 |
IMF2 | ARIMA(3,0,3) | -338.256 832 6 | |
RES | ARIMA(2,5,1) | -458.034 650 8 | |
S12 | IMF1 | ARIMA(2,0,0) | -122.880 141 4 |
IMF2 | ARIMA(3,0,0) | -270.519 404 0 | |
RES | ARIMA(2,5,2) | -388.038 083 2 | |
S13 | IMF1 | ARIMA(0,0,2) | -120.624 432 6 |
IMF2 | ARIMA(2,0,2) | -256.023 114 9 | |
RES | ARIMA(3,5,2) | -399.506 224 9 | |
S14 | IMF1 | ARIMA(3,0,2) | -149.787 730 8 |
IMF2 | ARIMA(3,0,0) | -272.093 268 5 | |
RES | ARIMA(2,5,2) | -363.573 426 3 | |
S15 | IMF1 | ARIMA(0,0,1) | -119.290 999 9 |
IMF2 | ARIMA(2,0,2) | -244.530 096 7 | |
RES | ARIMA(0,5,2) | -470.177 403 5 | |
S16 | IMF1 | ARIMA(2,0,3) | -98.468 829 4 |
IMF2 | ARIMA(0,2,3) | -321.898 537 0 | |
RES | ARIMA(0,4,2) | -441.287 207 4 | |
S17 | IMF1 | ARIMA(2,0,0) | -109.495 702 3 |
IMF2 | ARIMA(1,2,2) | -209.037 666 4 | |
RES | ARIMA(0,4,1) | -552.550 879 2 | |
S18 | IMF1 | ARIMA(3,0,0) | -127.782 178 4 |
IMF2 | ARIMA(2,0,3) | -253.470 211 9 | |
RES | ARIMA(2,5,2) | -445.574 006 2 | |
S19 | IMF1 | ARIMA(0,0,2) | -99.786 397 0 |
IMF2 | ARIMA(2,3,1) | -251.883 057 8 | |
RES | ARIMA(3,4,0) | -646.644 290 8 | |
S20 | IMF1 | ARIMA(1,0,2) | -138.051 598 3 |
IMF2 | ARIMA(2,0,2) | -222.278 571 2 | |
IMF3 | ARIMA(2,5,2) | -359.904 937 7 | |
RES | ARIMA(0,4,1) | -617.872 007 5 | |
S21 | IMF1 | ARIMA(2,0,3) | -98.966 377 1 |
IMF2 | ARIMA(2,2,3) | -215.117 634 5 | |
RES | ARIMA(2,4,1) | -387.051 278 3 |
2.3.2 ICEEMDAN-ARIMA模型预测分析
表5 新疆三屯河灌区 ICEEMDAN-ARIMA组合模型预测精度评价Table 5 Evaluation of the prediction accuracy of the ICEEMDAN-ARIMA combined model in the Santun river irrigation area of Xinjiang |
组合模型 | 评价指标 | ||
---|---|---|---|
RMSE | MAE | R 2 | |
ICEEMDAN-ARIMA-春 | 0.083 | 0.061 | 0.968 |
ICEEMDAN-ARIMA-夏 | 0.076 | 0.061 | 0.965 |
ICEEMDAN-ARIMA-秋 | 0.074 | 0.058 | 0.954 |
ICEEMDAN-ARIMA模型均值 | 0.078 | 0.060 | 0.962 |
CEEMD-ARIMA-春 | 0.108 | 0.079 | 0.943 |
CEEMD-ARIMA-夏 | 0.101 | 0.077 | 0.940 |
CEEMD-ARIMA-秋 | 0.099 | 0.076 | 0.929 |
CEEMD-ARIMA模型均值 | 0.103 | 0.077 | 0.937 |
ARIMA-春 | 0.358 | 0.256 | 0.794 |
ARIMA-夏 | 0.351 | 0.267 | 0.786 |
ARIMA-秋 | 0.345 | 0.253 | 0.780 |
ARIMA模型均值 | 0.351 | 0.259 | 0.787 |