Google Earth Engine ——数据全解析专辑（COPERNICUS/S2_SR）20154至今哨兵-2号(SR) 数据集

Sentinel-2 is a wide-swath, high-resolution, multi-spectral imaging mission supporting Copernicus Land Monitoring studies, including the monitoring of vegetation, soil and water cover, as well as observation of inland waterways and coastal areas.

The Sentinel-2 L2 data are downloaded from scihub. They were computed by running sen2cor. WARNING: ESA did not produce L2 data for all L1 assets, and earlier L2 coverage is not global.

The assets contain 12 UINT16 spectral bands representing SR scaled by 10000 (unlike in L1 data, there is no B10). There are also several more L2-specific bands (see band list for details). See the Sentinel-2 User Handbook for details. In addition, three QA bands are present where one (QA60) is a bitmask band with cloud mask information. For more details, see the full explanation of how cloud masks are computed.

EE asset ids for Sentinel-2 L2 assets have the following format: COPERNICUS/S2_SR/20151128T002653_20151128T102149_T56MNN. Here the first numeric part represents the sensing date and time, the second numeric part represents the product generation date and time, and the final 6-character string is a unique granule identifier indicating its UTM grid reference (see MGRS).

Clouds can be removed by using COPERNICUS/S2_CLOUD_PROBABILITY. See this tutorial explaining how to apply the cloud mask.

For more details on Sentinel-2 radiometric resolution, see this page.

Sentinel-2 是一个宽幅、高分辨率、多光谱成像任务，支持哥白尼土地监测研究，包括监测植被、土壤和水覆盖，以及观察内陆水道和沿海地区。

Sentinel-2 L2 数据从 scihub 下载。它们是通过运行 sen2cor 来计算的。警告：ESA 没有为所有 L1 资产生成 L2 数据，早期的 L2 覆盖范围不是全球性的。

资产包含 12 个 UINT16 光谱带，代表按 10000 缩放的 SR（与 L1 数据不同，没有 B10）。还有几个特定于 L2 的频段（有关详细信息，请参阅频段列表）。有关详细信息，请参阅 Sentinel-2 用户手册。此外，存在三个 QA 带，其中一个 (QA60) 是具有云掩码信息的位掩码带。有关更多详细信息，请参阅有关如何计算云掩码的完整说明。

Sentinel-2 L2 资产的 EE 资产 ID 具有以下格式：COPERNICUS/S2_SR/20151128T002653_20151128T102149_T56MNN。这里的第一个数字部分表示感应日期和时间，第二个数字部分表示产品生成日期和时间，最后的 6 个字符串是一个唯一的颗粒标识符，表示其 UTM 网格参考（参见 MGRS）。

可以使用 COPERNICUS/S2_CLOUD_PROBABILITY 去除云。请参阅本教程，解释如何应用云遮罩。

有关 Sentinel-2 辐射分辨率的更多详细信息，请参阅此页面。

Dataset Availability

2017-03-28T00:00:00 - 2021-09-04T00:00:00

Dataset Provider

European Union/ESA/Copernicus

Collection Snippet

ee.ImageCollection("COPERNICUS/S2_SR")

Bands Table

Class Table: SCL

影像属性：

代码：

function maskS2clouds(image) {
  var qa = image.select('QA60');
  // Bits 10 and 11 are clouds and cirrus, respectively.
  var cloudBitMask = 1 << 10;
  var cirrusBitMask = 1 << 11;
  // Both flags should be set to zero, indicating clear conditions.去云操作
  var mask = qa.bitwiseAnd(cloudBitMask).eq(0)
      .and(qa.bitwiseAnd(cirrusBitMask).eq(0));
  return image.updateMask(mask).divide(10000);
}
// Map the function over one year of data and take the median.
// Load Sentinel-2 TOA reflectance data.
var dataset = ee.ImageCollection('COPERNICUS/S2')
                  .filterDate('2018-01-01', '2018-06-30')
                  // Pre-filter to get less cloudy granules.
                  .filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', 20))
                  .map(maskS2clouds);
var rgbVis = {
  min: 0.0,
  max: 0.3,
  bands: ['B4', 'B3', 'B2'],
};
Map.setCenter(-9.1695, 38.6917, 12);
Map.addLayer(dataset.median(), rgbVis, 'RGB');

影像：