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基于VTCI空間尺度上推方法的干旱影響評估
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國家自然科學(xué)基金項(xiàng)目(41371390)


Drought Impact Assessment Based on Spatial Up-scaling Methods of Vegetation Temperature Condition Index
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    基于關(guān)中平原Aqua MODIS 條件植被溫度指數(shù)(VTCI)的干旱監(jiān)測結(jié)果,分別采用分布式和聚合式的主導(dǎo)類變異權(quán)重法(DCVW)、算術(shù)平均值變異權(quán)重法(AAVW)和中值變異權(quán)重法(MPVW)對市域單元內(nèi)VTCI進(jìn)行空間尺度上推,以獲取冬小麥主要生育期聚合后的加權(quán)VTCI;以加權(quán)VTCI與冬小麥產(chǎn)量間的回歸分析精度為參考,選擇最為合適的空間尺度上推方法。結(jié)果表明:采用分布式獲得的加權(quán)VTCI與冬小麥產(chǎn)量的回歸分析結(jié)果整體優(yōu)于聚合式獲得的結(jié)果。在分布式的上推過程中,MPVW獲得的加權(quán)VTCI與冬小麥產(chǎn)量間的回歸分析精度較低,DCVW和AAVW的精度均較高,其中DCVW獲得的加權(quán)VTCI與冬小麥產(chǎn)量間回歸分析的決定系數(shù)R2達(dá)0.64,精度最高,說明采用分布式DCVW對市域單元內(nèi)VTCI進(jìn)行空間尺度上推得到的加權(quán)VTCI最為合理。

    Abstract:

    Up-scaling method for inferring spatial information from a pixel scale to a basic unit scale has significant effects on aggregating results and decision-making. Therefore, developing appropriate methods to accurately up-scale spatial data is the key to infer useful drought information. The time series of vegetation temperature condition index (VTCI) drought monitoring results in Guanzhong Plain from early March to late May in the years from 2008 to 2013 were spatially transformed from a pixel scale to a basic unit scale by using the dominant class variability-weighted method (DCVW), arithmetic average variability-weighted method (AAVW) and median pixel variability-weighted method (MPVW) in the distributed mode and aggregated mode to obtain the aggregated VTCIs. The weighted VTCIs of winter wheat in main growth period were calculated, and the regression analysis between the weighted VTCIs and winter wheat yields was applied as references to evaluate up-scaling methods. The results showed that the regression analysis results of the three methods in the distributed up-scaling mode were generally better than those in the aggregated upscaling mode. The regression analysis results in the distributed up-scaling mode also indicated that the computing accuracy was high by DCVW and AAVW and was low by MPVW. DCVW in the distributed up-scaling mode was the most accurate method with the highest determination coefficient and the lowest estimated standard error, which were 0.64 and 289.97kg/hm2, respectively. The estimation yields of winter wheat which obtained by DCVW were very close to the levels of statistics yearbook of Shaanxi Province, indicating that the estimation precision of DCVW mehtod was high, and the method was robust. Overall, the method of DCVW in distributed up-scaling mode was the most reasonable approach to up-scale VTCIs in Guanzhong Plain from a pixel scale to a basic unit scale.

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白雪嬌,王鵬新,張樹譽(yù),李俐,王蕾,解毅.基于VTCI空間尺度上推方法的干旱影響評估[J].農(nóng)業(yè)機(jī)械學(xué)報,2017,48(2):172-178. BAI Xuejiao, WANG Pengxin, ZHANG Shuyu, LI Li, WANG Lei, XIE Yi. Drought Impact Assessment Based on Spatial Up-scaling Methods of Vegetation Temperature Condition Index[J]. Transactions of the Chinese Society for Agricultural Machinery,2017,48(2):172-178.

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  • 收稿日期:2016-06-16
  • 最后修改日期:2017-02-10
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  • 在線發(fā)布日期: 2017-02-10
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