当前位置：首页 > news >正文

基于 GEE 的 2019 - 2024 年研究区大气污染物浓度月度变化趋势（CO、NO₂、SO₂、O₃ 、HCHO）

news 来源：原创 2025/5/13 10:57:14

1 完整代码

2 运行结果

本文使用Copernicus Sentinel-5P卫星的NRTI L3数据集，监测研究区2019-2024年的CO、NO₂、SO₂、O₃和HCHO的月度变化，单位均为mol/m^2。

1 完整代码

var roi = table;

var time_start = '2019-01-01';
var time_end = '2024-12-31';

var co = ee.ImageCollection('COPERNICUS/S5P/NRTI/L3_CO')
  .select('CO_column_number_density')
  .filterDate(time_start, time_end)
  .filterBounds(roi);

var no2 = ee.ImageCollection('COPERNICUS/S5P/NRTI/L3_NO2')
  .select('NO2_column_number_density')
  .filterDate(time_start, time_end)
  .filterBounds(roi);

var so2 = ee.ImageCollection('COPERNICUS/S5P/NRTI/L3_SO2')
  .select('SO2_column_number_density')
  .filterDate(time_start, time_end)
  .filterBounds(roi);

var o3 = ee.ImageCollection('COPERNICUS/S5P/NRTI/L3_O3')
  .select('O3_column_number_density')
  .filterDate(time_start, time_end)
  .filterBounds(roi);

var hcho = ee.ImageCollection('COPERNICUS/S5P/NRTI/L3_HCHO')
  .select('tropospheric_HCHO_column_number_density')
  .filterDate(time_start, time_end)
  .filterBounds(roi);

var months = ee.List.sequence(1, 12);
var years = ee.List.sequence(2019, 2024);

function monthlyAverage(imgCol, bandName) {
  var monthlyMeans = years.map(function(year) {
    return months.map(function(month) {
      var start = ee.Date.fromYMD(year, month, 1);
      var end = start.advance(1, 'month');
      
      var monthlyCol = imgCol.filterDate(start, end);
      var meanImg = monthlyCol.mean().set({
        'year': year,
        'month': month,
        'system:time_start': start.millis()
      });
      return meanImg;
    });
  }).flatten();
  
  return ee.ImageCollection(monthlyMeans);
}

var coMonthly = monthlyAverage(co, 'CO_column_number_density');
var no2Monthly = monthlyAverage(no2, 'NO2_column_number_density');
var so2Monthly = monthlyAverage(so2, 'SO2_column_number_density');
var o3Monthly = monthlyAverage(o3, 'O3_column_number_density');
var hchoMonthly = monthlyAverage(hcho, 'tropospheric_HCHO_column_number_density');

function chartTimeSeries(imageCollection, bandName, title, yLabel) {
  var chart = ui.Chart.image.series({
    imageCollection: imageCollection.select(bandName),
    region: roi,
    reducer: ee.Reducer.mean(),
    scale: 10000
  })
  .setOptions({
    title: title,
    hAxis: { title: 'Time', format: 'YYYY-MM' },
    vAxis: { title: yLabel },
    lineWidth: 2,
    pointSize: 3,
    series: {
      0: { color: 'red' }
    }
  });
  
  return chart;
}

var coChart = chartTimeSeries(coMonthly, 'CO_column_number_density', 'CO Monthly Variation (2019-2024)', 'CO Density');
var no2Chart = chartTimeSeries(no2Monthly, 'NO2_column_number_density', 'NO₂ Monthly Variation (2019-2024)', 'NO₂ Density');
var so2Chart = chartTimeSeries(so2Monthly, 'SO2_column_number_density', 'SO₂ Monthly Variation (2019-2024)', 'SO₂ Density');
var o3Chart = chartTimeSeries(o3Monthly, 'O3_column_number_density', 'O₃ Monthly Variation (2019-2024)', 'O₃ Density');
var hchoChart = chartTimeSeries(hchoMonthly, 'tropospheric_HCHO_column_number_density', 'HCHO Monthly Variation (2019-2024)', 'HCHO Density');

print(coChart);
print(no2Chart);
print(so2Chart);
print(o3Chart);
print(hchoChart);