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雷達影像提取壟行結(jié)構(gòu)土壤含水率方法研究
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國家自然科學基金資助項目(41174068)和黃河流域基礎地質(zhì)環(huán)境遙感調(diào)查聯(lián)合資助項目(1212010911084)


SAR Images in Retrieving Soil Moisture of Periodic Surfaces with Row Structure
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    摘要:

    目前通過主動微波法建立的土壤含水率反演模型都是針對非周期的隨機粗糙地表,而不適用于周期性壟行結(jié)構(gòu)的地表。通過對全極化雷達影像和野外采樣數(shù)據(jù)的分析,證明了同極化(hh和vv)后向散射強度受壟行觀測方位角的影響可達4 dB,而交叉極化(vh)對方位角不敏感,據(jù)此建立了同極化后向散射強度隨方位角變化的響應函數(shù)。在hh和vv極化模式下,構(gòu)造的采樣點到響應函數(shù)曲線的距離參數(shù)與土壤體積含水率的相關系數(shù)分別為0.7095和0.8723,分離出了方位角的影響。同時通過3種極化組合方案消除了粗糙度參數(shù)的實測誤差對反演精度的影響。18個檢驗點的反演值與實測值之間的相關系數(shù)為0.9461,標準差為0.0366 cm3/cm3。證明了該模型對壟行結(jié)構(gòu)土壤含水率的反演是有效并可靠的。

    Abstract:

    The previous retrieval models of soil moisture based on active microwave remote sensing are applicable for non-periodic random surfaces, not available to periodic surfaces with row structure yet. This study was based on fully polarimetric data and field data. It was found that the like-polarized (hh and vv) backscattering coefficients react obviously to the azimuth angles, up to 4 dB. while the cross-polarized (vh) backscattering reacts insensitively to row-direction changes, then the response functions of hh and vv polarizations were given. A distance parameter that denotes the distance between a sampling point and response function curve was constructed to remove the influence of azimuth angles. The correlation coefficients between the distance parameter and soil moisture were 0.7095 and 0.8723, in hh and vv polarization modes, respectively. Meanwhile the influence of the error of roughness parameters in field measurement was removed by three different polarization combination schemes. The effectiveness of this model was demonstrated by the estimated soil moisture of checkpoints. This study selected 18 sampling points as checkpoints.The correlation coefficient between estimated soil moisture and measured soil moisture was up to 0.9461, the standard deviation was 0.0366 cm3/cm3. The model was reliable and applicable for periodic surfaces.

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尹楠,姜琦剛,王晶瑋,張建全.雷達影像提取壟行結(jié)構(gòu)土壤含水率方法研究[J].農(nóng)業(yè)機械學報,2013,44(12):154-159. Yin Nan, Jiang Qigang, Wang Jingwei, Zhang Jianquan. SAR Images in Retrieving Soil Moisture of Periodic Surfaces with Row Structure[J]. Transactions of the Chinese Society for Agricultural Machinery,2013,44(12):154-159.

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  • 在線發(fā)布日期: 2013-12-05
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