An Improved Upscaling Method of In Situ Measurements With Consideration of Their Uncertainty for the Spatial Scale Match Between Satellite and In Situ Measurements
An Improved Upscaling Method of In Situ Measurements With Consideration of Their Uncertainty for the Spatial Scale Match Between Satellite and In Situ Measurements
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DOI：
10.1109/tgrs.2023.3291883
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发表时间：
2023
影响因子：
8.2
通讯作者：
XiangLei Du;Xiaodan Wu;R. Tang;Qicheng Zeng;Zheng Li;Jingping Wang;Zhiyong Jiang;Kaizhong Wang-Kaiz
中科院分区：
文献类型：
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作者：
XiangLei Du;Xiaodan Wu;R. Tang;Qicheng Zeng;Zheng Li;Jingping Wang;Zhiyong Jiang;Kaizhong Wang-Kaiz
通过在粗像素内部署多个原位站点，可以减少卫星和基于原位的测量之间的空间尺度失配。然而，由于其“点”测量特性，仍有必要将现场测量从地面支撑尺度提升到粗像素尺度。以往的尺度放大方法一般都是针对现场测量而开发的。然而，现场测量的不确定性，如测量误差和空间代表性误差，没有得到处理。因此，放大结果不可避免地遭受误差，其最终将传播到像素尺度地面“真实”。本文首次基于误差理论和测量平差理论，提出了一种考虑现场测量不确定度的改进尺度放大方法。通过比较修正后的尺度放大结果与不考虑现场测量不确定性的尺度放大系数的结果，评价了修正后的尺度放大系数的有效性。结果表明，在现场测量不确定度较大的情况下，尺度放大结果的精度可提高11.06%。然而，如果现场测量的不确定性可以忽略不计，则校正的升尺度模型是不必要的，因为它不会带来很多好处。虽然这种方法的有效性只在有限的研究区域进行了测试，但它是迈向更高精度的像素级地面“真相”的重要的第一步，特别是当现场测量的不确定性不可忽略时。
The spatial scale mismatch between satellite and in situ-based measurements can be reduced by deploying multiple in situ sites within the coarse pixel. However, upscaling in situ measurements from the ground-support scale to the coarse pixel scale is still necessary due to their “point” measurement characteristics. The previous upscaling methods were generally developed merely for the in situ measurements. Nevertheless, the uncertainty of in situ measurements, such as measurement errors and spatial representativeness errors, was not dealt with. Consequently, the upscaling results inevitably suffer from errors, which will finally propagate into the pixel scale ground “truth.” For the first time, this study presents an improved upscaling method with the consideration of the uncertainty of in situ measurements based on the error theory and measurement adjustment theory. The effectiveness of the corrected upscaling coefficients was evaluated by comparing the accuracy of the corrected upscaling results with those based on the upscaling coefficients without considering the uncertainty of in situ measurements. The results indicate that the accuracy of the upscaling results can be enhanced by 11.06% in the condition in which in situ measurements suffer from large uncertainty. However, if the uncertainty of in situ measurements is negligible, the corrected upscaling model is not necessary because it does not bring many benefits. Although the effectiveness of this method was only tested on a limited study area, it makes an important first step toward a higher precision pixel-scale ground “truth,” especially when the uncertainty of in situ measurements is nonnegligible.