时序变差函数特征驱动下的月平均降水空间分布模拟

Simulation of Spatial Distribution of Monthly Average Precipitation Driven by Temporal Variation Function

  • 摘要: 高精度降水场是水文、气象以及环境分析的重要数据支撑,直接影响相关服务的准确性。传统降水分布模拟大多依赖站点空间维的驱动因素,而忽略了降水时序变化特征对其空间分布的影响。使用2015—2017年中国湖北省83个国家气象观测站点和28个省级观测站点近3 a月平均累积降水资料,通过相关性分析,引入站点降水时序理论变差函数模型的拱高值(C)和块金值(C0)作为影响因素,使用地理加权回归(geographically weighted regression, GWR)建立湖北省月平均降水分布模型。结果表明:(1)各站点降水的时序变差函数曲线与降水的季节性基本吻合。站点时序理论变差函数模型中,有25.3%能够在4个月内达到平稳,36.14%在6个月内达到平稳。(2)站点降水时序理论变差函数模型的CC0与逐年12月平均累积降水在0.01水平(双侧)上显著相关,平均相关系数分别为0.745和0.526,大于地理位置和高程对降水的影响。(3)引入CC0 有助于提升GWR模型的整体拟合优度和插值精度。对比仅使用经纬度的GWR模型和引入时序理论变差函数特征的GWR模型,3 a平均整体拟合优度从0.852提升至0.912。验证集站点插值精度评价显示,3 a绝对误差、均方根误差和平均绝对百分误差下降幅度均大于60%。因此,引入时序理论变差函数特征的时空GWR模型能够获得较高精度的降水模拟结果,更适合具有丰富历史降水资料地区的降水空间分布估算。

     

    Abstract:
      Objectives  High-precision precipitation field is important data support for hydrological, meteorological, and environmental analysis, which directly affects the accuracy of relevant services.The traditional simulation of precipitation distribution mostly relies on the spatial driving factors but neglects the impact of the temporal characteristics of precipitation on its spatial distribution.
      Methods  We employ the average cumulative precipitation data from 83 national meteorological stations and 28 provincial meteorological stations in Hubei Province from 2015 to 2017. According to the correlation analysis, the arch height (C) and nugget value (C0) of the theoretical semivariogram model of precipitation time series are introduced as the influencing factors. We apply the geographically weighted regression (GWR) model to simulate the monthly average precipitation distribution model of Hubei Province.
      Results  The results show that: (1)The time-series semivariogram curve of monthly precipitation at each station is consistent with the seasonality of precipitation. 25.3% of the theoretical variation function model of site time series become stable in 4 months, and 36.14% in 6 months.(2)C and C0 of the theoretical variation function model of precipitation time series at each station are correlated with the annual average cumulative precipitation in December of 0.01 level (both sides). The average correlation coefficients are 0.745 and 0.526, which are greater than the influence of geographical location and elevation on precipitation.(3)The introduction of C and C0 is helpful to improve the global goodness of fit and interpolation accuracy of GWR model. By comparing the GWR model with latitude and longitude and the GWR model with variation function features of time series theory, the three-year average overall goodness of fit increased from 0.852 to 0.912. The accuracy evaluation of interpolation in the verification set site showed that the mean absolute error, the root mean square error and the mean absolute percentage error all declined by more than 60% in three years.
      Conclusions  Therefore, the spatial-temporal weighted regression model with time series theory variational function features can obtain high precision precipitation simulation results and is more suitable for the estimation of precipitation spatial distribution in the regions with abundant historical precipitation data.

     

/

返回文章
返回