Google Earth Engine（GEE）——利用sentinel-5P数据进行中国区域so2二氧化硫的2019-2020年差异分析

数据简介：

OFFL/L3_SO2

This dataset provides offline high-resolution imagery of atmospheric sulfur dioxide (SO2) concentrations.

Sulphur dioxide (SO2) enters the Earth’s atmosphere through both natural and anthropogenic processes. It plays a role in chemistry on a local and global scale and its impact ranges from short-term pollution to effects on climate. Only about 30% of the emitted SO2 comes from natural sources; the majority is of anthropogenic origin. SO2 emissions adversely affect human health and air quality. SO2 has an effect on climate through radiative forcing, via the formation of sulphate aerosols. Volcanic SO2 emissions can also pose a threat to aviation, along with volcanic ash. S5P/TROPOMI samples the Earth’s surface with a revisit time of one day with unprecedented spatial resolution of 3.5 x 7 km which allows the resolution of fine details including the detection of much smaller SO2 plumes. [More information]

For this L3 SO2 product, the absorbing_aerosol_index is calculated with a pair of measurements at the 340 nm and 380 wavelengths. The COPERNICUS/S5P/OFFL/L3_AER_AI product has the absorbing_aerosol_index calculated using the 354 nm and 388 nm wavelengths.

OFFL/L3_SO2 该数据集提供大气中二氧化硫（SO2）浓度的离线高分辨率图像。

二氧化硫（SO2）通过自然和人为的过程进入地球的大气层。它在地方和全球范围内的化学中起着作用，其影响范围从短期污染到对气候的影响。只有大约30%的二氧化硫排放来自于自然来源；大部分是人为的。二氧化硫的排放对人类健康和空气质量有不利影响。二氧化硫通过硫酸盐气溶胶的形成，通过辐射强迫对气候产生影响。火山SO2排放与火山灰一起也会对航空构成威胁。S5P/TROPOMI对地球表面进行采样，重访时间为一天，具有前所未有的3.5 x 7公里的空间分辨率，这使得对细微细节的分辨率包括对更小的SO2羽流的探测。[更多信息］

对于这个L3 SO2产品，吸收_气溶胶指数是用340纳米和380波长的一对测量值计算的。COPERNICUS/S5P/OFFL/L3_AER_AI产品的吸收气溶胶指数是用354纳米和388纳米波长计算的。

Dataset Availability

2018-12-05T11:53:01 -

Dataset Provider

European Union/ESA/Copernicus

Collection Snippet

ee.ImageCollection("COPERNICUS/S5P/OFFL/L3_SO2")

Resolution

1113.2 meters

Bands Table

* = Values are estimated

代码：

// 分别定义两年的影响数据筛选

var y2019 = ee.ImageCollection("COPERNICUS/S5P/OFFL/L3_SO2").filterDate("2019-02-01","2019-02-28");
var y2020 = ee.ImageCollection("COPERNICUS/S5P/OFFL/L3_SO2").filterDate("2020-02-01","2020-02-28");

//获取中国边界
var countries = ee.FeatureCollection("USDOS/LSIB_SIMPLE/2017").filter(ee.Filter.eq("country_co", "CH"))

// 上色
var band_viz = {
  min: 0.0,
  max: 0.0005,
  palette: ['black', 'blue', 'purple', 'cyan', 'green', 'yellow', 'red']
};
//图层加载
Map.addLayer(y2019.max().select("SO2_column_number_density").clip(countries),band_viz," 2019");
Map.addLayer(y2020.max().select("SO2_column_number_density").clip(countries),band_viz," 2020");

结果：

图涉及中国区域没法展示，大家自己copy 代码去实现