feat(S1andS2_download): 完善Sentinel-2 L2A数据缺失情况下的平替处理逻辑.

GEE_Scripts/S1andS2_download.js

@@ -2,15 +2,15 @@
  * Sentinel-1 & Sentinel-2 哨兵一号与二号长时序数据下载 —— 适用于小范围区域年度数据获取
  *
  * @author CVEO Team
- * @date 2026-01-06
+ * @date 2026-01-07
  *
- * 1. 加载 Sentinel-1, Sentinel-2 数据与 Cloud Score+ 云掩膜, 以及 HLS 数据
+ * 1. 加载 Sentinel-1 GRD, Sentinel-2 L2A SR数据与 Cloud Score+ 云掩膜, 以及 HLS 数据
  * 2. 合成年度Sentinel-1, Sentinel-2, HLS无云影像
- * 3. 使用 HLS 影像作为 Sentinel-2 影像的补充
+ * 3. 使用 Sentinel-2 L1C TOA 影像与 HLS 影像作为 Sentinel-2 L2A SR 影像的补充
  * 4. 合并 Sentinel-1 和 Sentinel-2 影像
  * 5. 导出 COG 云优化并填补缺失值的 GeoTIFF 影像 (小区域不分块)
  *
- * 注: 截止至 2026-01-05, GEE 仍未集成 2015-2017 年的 L2A 数据, 且 2018 年的 L2A 数据仍不完整.
+ * 注: 截止至 2026-01-07, GEE 仍未集成 2015-2017 年的 Sentinel-2 L2A SR数据, 且 2018 年的 L2A 数据仍不完整.
  */
 
 // 加载研究区域和影像
@@ -20,7 +20,7 @@ var name_list = [
   "高雄左营区左营军港",
   "高雄旗山区陆军第八军团指挥部",
 ];
-var target_index = 0; // 从 0 开始计数, 0-3
+var target_index = 1; // 从 0 开始计数, 0-3
 var region_name = name_list[target_index];
 var region = ee.FeatureCollection(
   demoPoints
@@ -29,7 +29,7 @@ var region = ee.FeatureCollection(
     .buffer(3000)
     .bounds()
 );
-var start_year = 2018;
+var start_year = 2015;
 var end_year = 2025;
 var start_date = start_year + "-" + "01-01";
 var end_date = start_year + "-" + "12-31";
@@ -38,6 +38,7 @@ var cloud_threshold = 100; // 最大云量阈值
 var QA_BAND = "cs_cdf";
 // The threshold for masking; values between 0.50 and 0.65 generally work well.
 // Higher values will remove thin clouds, haze & cirrus shadows.
+// 内陆建议设置为 0.8, 沿海或大江大湖旁建议设置为 0.6
 var CLEAR_THRESHOLD = 0.8;
 var L30Bands = ["B2", "B3", "B4", "B5", "B6", "B7"];
 // Sentinel-2的B8A波段(20m)可能更适合代表近红外波段
@@ -156,7 +157,7 @@ var S1VVdataset = S1dataset.filter(
 var S1VHdataset = S1dataset.filter(
   ee.Filter.listContains("transmitterReceiverPolarisation", "VH")
 ).select("VH");
-print(start_date + " - " + end_date + " S1dataset", S1dataset);
+print(start_date + " - " + end_date + " Sentinel-1 dataset", S1dataset);
 var s1_vv_img = ee.Image(S1VVdataset.median());
 var s1_vh_img = ee.Image(S1VHdataset.median());
 
@@ -167,22 +168,47 @@ var s1_vh_img = ee.Image(S1VHdataset.median());
 // Cloud Score+ image collection.
 // Note Cloud Score+ is produced from Sentinel-2 level 1C data and can be applied to either L1C or L2A collections.
 var S2csPlus = ee.ImageCollection("GOOGLE/CLOUD_SCORE_PLUS/V1/S2_HARMONIZED");
-var S2dataset = ee
+var S2TOAdataset = ee
+  .ImageCollection("COPERNICUS/S2_HARMONIZED")
+  .filter(common_filter)
+  .filter(ee.Filter.lt("CLOUDY_PIXEL_PERCENTAGE", cloud_threshold))
+  .linkCollection(S2csPlus, [QA_BAND])
+  .map(maskS2cloudsByCS)
+  .select(s2Bands, commonBands);
+var targetS2TOACol = sortedByPriority(S2TOAdataset, region);
+var s2_toa_img = ee.Image(targetS2TOACol.mosaic());
+// 加载SIAC工具集, 容易爆内存
+// var SIAC = require("users/marcyinfeng/utils:SIAC");
+// var s2_boa_img = SIAC.get_sur(s2_toa_img.clip(region));
+print(start_date + " - " + end_date + " Sentinel-2 TOA dataset", S2TOAdataset);
+
+var S2SRdataset = ee
   .ImageCollection("COPERNICUS/S2_SR_HARMONIZED")
   .filter(common_filter)
   .filter(ee.Filter.lt("CLOUDY_PIXEL_PERCENTAGE", cloud_threshold))
   .linkCollection(S2csPlus, [QA_BAND])
   .map(maskS2cloudsByCS)
   .select(s2Bands, commonBands);
-var targetS2Col = sortedByPriority(S2dataset, region);
+var targetS2SRCol = sortedByPriority(S2SRdataset, region);
-var s2_img = ee.Image(targetS2Col.mosaic());
+var s2_sr_img = ee.Image(targetS2SRCol.mosaic());
-print(start_date + " - " + end_date + " S2dataset", S2dataset);
+print(start_date + " - " + end_date + " Sentinel-2 SR dataset", S2SRdataset);
 
-// 2015-2018 年间若 Sentinel-2 数据为空, 则使用重采样到 10m 的 HLS 数据
+var s2_img = ee.Image();
-if (
+// 2015-2018 年间若 Sentinel-2 SR 数据为空, 则使用 Sentinel-2 TOA 数据
-  S2dataset.size().getInfo() === 0 ||
+// 若仍然没有, 则使用重采样到 10m 的 HLS 数据
-  (start_year === 2018 && (target_index === 0 || target_index === 3))
+if (S2SRdataset.size().getInfo() === 0 && S2TOAdataset.size().getInfo() !== 0) {
-) {
+  s2_img = s2_toa_img;
+} else if (S2TOAdataset.size().getInfo() === 0 || start_year === 2015) {
+  s2_img = hls_10m_img;
+} else {
+  s2_img = s2_sr_img;
+}
+
+// 针对试点区域的特殊设置
+if (start_year === 2018 && (target_index === 0 || target_index === 3)) {
+  s2_img = s2_toa_img;
+}
+if (start_year === 2016 && target_index === 1) {
   s2_img = hls_10m_img;
 }
 
@@ -221,7 +247,7 @@ var styling = {
 Map.centerObject(region, 14);
 Map.addLayer(s1_vv_img, s1_vis, start_year + " Sentinel-1 GRD VV", false);
 Map.addLayer(s1_vh_img, s1_vis, start_year + " Sentinel-1 GRD VH", false);
-Map.addLayer(hls_img, true_rgb_vis, start_year + " HLS True RGB");
+Map.addLayer(hls_img, true_rgb_vis, start_year + " HLS True RGB 30m");
 Map.addLayer(hls_10m_img, true_rgb_vis, start_year + " HLS True RGB 10m");
 Map.addLayer(
   s2_img_frgb,