Sentinel-2数据目前在GEE中共有两种产品：一种是普通的没有经过大气校正的数据；另一种是经过大气校正后的数据（不全）。这两种数据去云的操作方法都是通过QA波段来完成的。

代码

var roi = /* color: #0b4a8b */ee.Geometry.Polygon(  
    [[[115.22447911987308, 38.97207826950874],  
     [117.64147130737308, 39.07450027191289],  
     [117.55358068237308, 40.67633196985795],  
     [114.91686193237308, 40.576272152256934]]]);  
Map.centerObject(roi, 7);  
//利用Sentinel-2自带的质量波段QA60通过按位运算去除云或阴影
function rmCloud(image) {  
  var qa = image.select('QA60');  
 var cloudBitMask = 1 << 10;  
  var cirrusBitMask = 1 << 11;  
  var mask = qa.bitwiseAnd(cloudBitMask).eq(0)  
               .and(qa.bitwiseAnd(cirrusBitMask).eq(0)); 
 return image.updateMask(mask);  
}  
var rawImage = ee.Image("COPERNICUS/S2/20180118T031039_20180118T031037_T50SMJ");  
var visParams = {  
  bands: ['B4', 'B3', 'B2'],  
  min: 0,  
  max: 3000  
};  
print("rawImage", rawImage);  
Map.addLayer(rawImage, visParams, "rawImage");  
var cleanImage = rmCloud(rawImage);  
print("cleanImage", cleanImage);  
Map.addLayer(cleanImage, visParams, "cleanImage"); 

结果