2022年江西省极端干旱对柑橘种植经济损失的遥感评估

Remote Sensing Evaluation of Economic Losses of Citrus Planting Caused by Extreme Drought in Jiangxi Province in 2022

2022年江西省发生极端干旱灾害,对柑橘生长及产量造成了十分严重的影响。利用遥感技术快速、准确地评估干旱受灾程度对柑橘种植减损及后续稳产具有重要意义。采用2022年Landsat遥感影像数据、江西省土地利用类型数据和Google Earth柑橘监督分类样本点数据识别并提取了江西省柑橘种植区;在此基础上,利用2021年及2022年MODIS数据产品分别计算江西省柑橘关键生育期(6~10月)的归一化差值植被指数(NDVI)和地表温度(LST),用以联合反演温度-植被干旱指数(TVDI);再结合江西省统计年鉴中的柑橘种植面积数据及实地调研数据,定量评估了4种情形下2022年江西省极端干旱对柑橘种植造成的经济损失。研究结果表明:①2021年和2022年6月~10月江西省柑橘种植区TVDI平均值分别为0.83和0.62,2022年干旱胁迫明显加重;②2022年6月~10月江西省柑橘种植区重度干旱占66.1%,中度干旱占33.7%,且干旱空间分布具有赣北大于赣南的空间格局;③2022年7月初~11月初,江西省柑橘种植区TVDI长时间维持在0.8以上,表现为重度干旱,此时段与柑橘关键生育期重合,对柑橘果实生长影响巨大;④2022年江西省柑橘产量平均减产率达到58.2%,柑橘种植的经济损失呈现由北向南增加的趋势,赣南、赣中以及赣北的直接经济损失依次为49.64亿元、45.17亿元、19.84亿元。研究结果有助于政府部门快速摸清江西省果农受灾情况,并为后续柑橘种植的抗旱救灾、减损保产提供一定的决策依据。

The extreme drought disaster in Jiangxi Province in 2022 severely affected the growth and yield of cit⁃rus.It is of great significance to use remote sensing technology to assess the degree of drought damage quickly and accurately for reducing losses of citrus planting and subsequent stabilize yield.The citrus planting areas of Ji⁃angxi Province were identified and extracted by using the 2022 Landsat remote sensing image data,the land use type data of Jiangxi Province,and the Google Earth citrus supervised classification sample point data.On this basis,the Normalized Difference Vegetation Index(NDVI)and Land Surface Temperature(LST)of the key growth period(June-October)of citrus in Jiangxi Province were calculated by using the MODIS data products of 2021 and 2022,which used for joint inversion of Temperature-Vegetation Drought Index(TVDI).Com⁃bined with the citrus planting area data of Jiangxi Province Statistical Yearbook and field survey data,the eco⁃nomic losses caused by extreme drought in 2022 in Jiangxi Province were quantitatively assessed under four cas⁃es.The results showed as follows:(1)The average TVDI of citrus planting areas in Jiangxi Province from June to October in 2021 and 2022 were 0.83 and 0.62,respectively,and drought stress increased significantly in 2022;(2)Severe drought accounted for 66.1%and moderate drought accounted for 33.7%in the citrus plant⁃ing area of Jiangxi Province from June to October 2022,and the spatial distribution of drought was more severe in northern Jiangxi Province than in southern Jiangxi Province.(3)From early July to early November 2022,TVDI of citrus planting areas in Jiangxi Province remained above 0.8 for a long time,which was characterized by severe drought.This period coincided with the key growth period of citrus and had a great impact on citrus growth.(4)In 2022,the average reduction rate of citrus yield in Jiangxi Province reached 58.2%,and the eco⁃nomic loss of citrus planting showed an increasing trend from north to south.The direct economic loss of south⁃ern,central,and northern Jiangxi Province were 4.964 billion yuan,4.517 billion yuan,and 1.984 billion yuan,respectively.The research results are helpful for the government to quickly find out the disaster situation of cit⁃rus farmers in Jiangxi Province,and provide a certain basis for the decision of citrus planting drought relief,loss reduction,and yield guarantee of citrus planting in the future.