四川省不同SPEI指数计算方法适用性评价

为探究不同参考作物腾发量(ET₀)算法及相应标准化降水蒸散指数(SPEI)在四川省的适用性，针对四川省3个区域(川西高原、川西南山地和川中盆地),利用34个气象站点1967—2016年的气象资料，以Penman-Monteith(PM)法计算的ET₀为标准，对FAO-24Radiation(FAO-Ra)、Priestley-Taylor(PT)、Makkink(MK)、Hargreaves-Samani(HS)、Blaney-Criddle(BC)、World Meteorological Organization(WMO)、Rohwer(Ro)7种方法的ET₀计算结果进行比较，并选取其中综合表现较好的3种方法进行相应的SPEI计算。通过时间序列分析、误差分析、K-S检验及小波分析等方法，探讨各区域不同ET₀算法下的SPEI适用性。结果表明：7种方法在不同区域计算精度差异显著，在川西高原及川西南山地，PT法均方根误差(RMSE)均在99.11 mm以下，大部分气象站点的相对误差(RE)介于-3.8...

Application Evaluation of Different SPEI Index Calculation Methods in Sichuan Province

Drought episodes have become the main natural hazards all over the world, resulting in a serious limitation to agricultural production. Based on the daily meteorological data of 34 meteorological stations in Sichuan Province from 1967 to 2016, the reference crop evapotranspiration (ET0) was calculated by comparing the Penman-Monteith method (PM) and seven simplified ET0 methods. The simplified ET0 methods included Hargreaves-Samani (HS) method, Blaney-Criddle (BC) method, Priestley-Taylor (PT) method, Makkink (MK) method, FAO-24Radiation (FAO-Ra) method, Rohwer (Ro) method and World Meteorological Organization (WMO) method. The standardized precipitation evapotranspiration index (SPEI) was calculated based on PM and the three ET0 methods with better performances. To obtain the best calculation methods and assess its adaptability, Sichuan Province was divided into three regions, such as western plateau, southwestern mountain, and central Sichuan basin. The applicability of corresponding SPEI was evaluated with different ET0 methods in each region by time series analysis, error analysis, K-S test and wavelet analysis. The results showed that there were significant differences in the calculation accuracy of seven methods in different regions. The PT method had the best applicability in western plateau and southwestern mountain although the root mean square error (RMSE) of PT method was below 99.11mm and the relative error (RE) of most sites was -3.8%~14.2%. The MK and Ro methods had the stable performances in three regions since the RMSE of both were below 160mm. The SPEI calculated on the basis of PM, MK, Ro and PT ET0 methods had the same trend in the same region. In the year with actual drought event, the minimum values of SPEI were less than 0 so it can identify historical drought events. SPEI_PT and SPEI_PM had the most similar periodic oscillation changes, and the periodic gap between SPEI_Ro and SPEI_PM was the largest. The SPEI correlation at 1 month timescale was better than that at 3 month and 12 month timescales. There was the best correlation between SPEI_MK and SPEI_PM at 1 month timescale, with the correlation coefficient (r) of 0.99 and RMSE of 0.15. Therefore, SPEI_MK can be used as an alternative to SPEI_PM under the condition of missing data. This research can provide a theoretical evidence for drought monitoring and mitigation in Sichuan Province, and it can also give a reference for research in other areas.