摘要: |
【目的】基于气象数据的脆弱性模型与基于遥感数据的变化检测是大范围农作物台风灾情快速评估的两种主要方法。气象数据驱动的方法适用于大尺度灾情评估,但是由于气象数据空间分辨率较粗,其灾情评估结果的空间分辨率也较粗,无法体现灾情的细尺度空间细节;而基于遥感数据的变化检测方法虽然能提供高分辨率灾情信息,但是受限于台风期间数据可获取性,难以用于大区域业务化的灾情评估。【方法】该文文章通过多尺度数据融合技术结合两种方法的优点,提出一种空间覆盖完整同时分辨率较高的大范围农田台风灾情快速评估方法。首先,基于2010—2019年对中国沿海地区农作物损害较大的25个台风样本的省级受灾面积与气象再分析数据(ECMWF Reanalysis v5, ERA5)对农作物的脆弱性模型进行中国区域的参数较准,用以估计粗分辨率(25 km)农田受损率;然后通过遥感数据计算灾害植被损害指数(Disaster Vegetation Damage Index, DVDI)刻画细分辨率的灾情空间细节,并基于该指标对气象数据驱动的脆弱性模型估算受灾率结果进行空间降尺度,最终得到250 m分辨率的农作物灾情评估结果。【结果】实验结果表明针对中国区域参数较准的脆弱性曲线模型可以用于评估大尺度上农作物台风灾情的空间分布,其估算的省级受灾面积与统计资料呈现一定程度的相关性(R2=0.38);通过融合遥感DVDI数据对该模型受损率估计结果进行降尺度后进一步增强灾情评估结果的空间细节,与两块高分影像目视判读对比显示出融合结果的空间分布细节与实际受灾情况具备较好的一致性。【结论】该文提出的适用于大区域高分辨率的农作物台风灾情快速评估方法有潜力应用于台风农田灾情的快速全面评估。 |
关键词: 脆弱性曲线 DVDI 降尺度 台风 农田灾情 快速评估 |
DOI: |
分类号: |
基金项目:国家重点研发计划资助 |
|
Study on Rapid Assessment Method of Crop Typhoon Disaster Based on Meteorological and Remote Sensing Data |
Zhu Chuanhai, Chen Xuehong, Ye Tao
|
Faculty of Geography Science, Beijing Normal University
|
Abstract: |
[Purpose] There are two main methods for crop damage assessment for typhoon disaster: fragility model based on meteorological data and change detection based on remote sensing data. The meteorological data-driven method is suitable for large-scale damage assessment, however is lack of fine-scale spatial details due to the coarse spatial resolution of meteorological data. The change detection method based on remote sensing data can assess the crop damage assessment at high spatial resolution, however, it is limited by the availability of data during typhoon period, leading to the difficulty on application in the operational system of rapid damage assessment. [Method] In this study, by combining the advantages of the above two methods with multi-scale data fusion technology, we proposed a crop damage assessment method for typhoon disaster, which is expected to produce the assessment result with complete spatial coverage and high spatial resolution. Firstly, based on the provincial crop damaged area for the 25 typhoons in coastal areas of China from 2010 to 2019 and ECMWF Reanalysis v5 ( ERA5 ), the crop fragility model was adjusted and used to estimate the crop damage rate at coarse resolution of 25 km in China. Then, the Disaster Vegetation Damage Index (DVDI) was calculated by Moderate-resolution Imaging Spectroradiometer (MODIS) data to capture the spatial details of the crop damage at 250 m resolution. Based on DVDI, the estimated crop damage rate at coarse resolution was spatially downscaled into a fine resolution of 250 m . [Result] The experimental results show that the fragility model adjusted by the census data of China can be used to evaluate the spatial distribution of typhoon induced crop damage at a large scale, and the estimated provincial crop damage area is positively correlated with the census data (R2 = 0.38). The spatial details of the crop damage rate were further enhanced by the proposed downscaling technique with fusing DVDI data derived from remote sensing. Visually comparison with two high-resolution images acquired before and after “Lekima” typhoon show that the spatial details of the downscaling crop damage rate are well consistent with the actual crop damage. [Conclusion] Therefore, the proposed crop damage assessment method for typhoon disasters has potential for rapidly assessing the typhoon induced crop damage with complete spatial coverage and high spatial resolution. |
Key words: Vulnerability curve DVDI Downscaling Typhoon Farmland disaster Rapid assessment |