基于Landsat数据合成和可视化研究区域内每年的 BAI 值，制作年际变化折线图，同时导出每年的栅格数据。需要的朋友只需修改研究区域和时间范围即可运行。燃烧面积指数 (Burn Area Index, BAI) 是一种遥感指标，用于定量识别火灾影响区域。它基于 Landsat 红光 (Red) 和近红外光 (Near-IR) 波段的反射率，计算每个像素与火灾后地表（如木炭）的光谱相似度。BAI 对植被燃烧后的木炭残留具有极强的响应能力，能够显著反映火灾后区域的变化。BAI 值越高，说明该区域受火灾影响的程度越大，适用于火灾监测与评估。![]()
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var geometry = table;Map.centerObject(geometry, 6);
var dataset = ee.ImageCollection('LANDSAT/COMPOSITES/C02/T1_L2_ANNUAL_BAI');
var startYear = 1984;var endYear = 2024;var years = ee.List.sequence(startYear, endYear);
var annualMeanBAI = years.map(function(year) { year = ee.Number(year); var startDate = ee.Date.fromYMD(year, 1, 1); var endDate = ee.Date.fromYMD(year, 12, 31);
var meanBAI = dataset .filterDate(startDate, endDate) .select('BAI') .mean() .reduceRegion({ reducer: ee.Reducer.mean(), geometry: geometry, scale: 1000, maxPixels: 1e13 }) .get('BAI');
return ee.Feature(null, { year: year, meanBAI: meanBAI });});
var annualMeanBAICollection = ee.FeatureCollection(annualMeanBAI);
print('Annual Mean BAI:', annualMeanBAICollection);
var chart = ui.Chart.feature.byFeature({ features: annualMeanBAICollection, xProperty: 'year', yProperties: ['meanBAI']}).setChartType('LineChart').setOptions({ title: 'Annual Mean BAI (1984-2024)', hAxis: { title: 'Year' }, vAxis: { title: 'Mean BAI' }, lineWidth: 2, pointSize: 4});print(chart);
Export.table.toDrive({ collection: annualMeanBAICollection, description: 'AnnualMeanBAI', fileFormat: 'CSV', folder: 'BAI_Exports'});
years.getInfo().forEach(function(year) { var startDate = year + '-01-01'; var endDate = year + '-12-31'; var yearCollection = dataset .filterDate(startDate, endDate) .select('BAI') .mean() .clip(geometry); Export.image.toDrive({ image: yearCollection, description: 'BAI_' + year, fileNamePrefix: 'BAI_' + year, scale: 100, region: geometry, maxPixels: 1e13, crs: "EPSG:4326", folder: 'BAI_Exports' });});
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