Visualizzazione post con etichetta Sentinel. Mostra tutti i post
Visualizzazione post con etichetta Sentinel. Mostra tutti i post

venerdì 21 aprile 2023

Earth Engine Sentinel 5P time series NO2

 Due script per scaricare serie tempo dei dati Sentinel 5P da Google Earth Engine dato un punto geografico




Tutti i dati

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var point = ee.Geometry.Point([11.097849, 43.793234]);
var sentinel = ee.ImageCollection('COPERNICUS/S5P/NRTI/L3_NO2');
var sentinelLST = sentinel.filterBounds(point)
.filterDate('2019-01-01', '2022-12-31')
.select('NO2_column_number_density');

sentinelLST = sentinelLST.map(function(img){
var date = img.get('system:time_start');
return img.multiply(100000).set('system_time_start', date);
});

var createTS = function(img){
var date = img.get('system_time_start');
var value = img.reduceRegion(ee.Reducer.mean(), point).get('NO2_column_number_density');
var ft = ee.Feature(null, {'system:time_start': date,
'date': ee.Date(date).format('Y/M/d'),
'value': value});
return ft;
};

var TS = sentinelLST.map(createTS);

var graph = ui.Chart.feature.byFeature(TS, 'system:time_start', 'value');

print(graph.setChartType("Sentinel 5P")
.setOptions({vAxis: {title: 'NO2'},
hAxis: {title: 'Date'}}));


Export.table.toDrive({collection: TS, selectors: 'date, value'});

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Medie Giornaliere

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var collection = ee.ImageCollection('COPERNICUS/S5P/OFFL/L3_NO2')
  .select('tropospheric_NO2_column_number_density')
var daily_data = ee.ImageCollection(ee.List.sequence(2019,2019).map(function(year){
  var date1 = ee.Date.fromYMD(year,1,1)
  var date2 = date1.advance(1,'year')
  //Calculate the number of days per year
  var doy = date2.difference(date1,'day')
  var doyList = ee.List.sequence(1,doy)
  //Daily image mean synthesis using doy
  var day_imgs = doyList.map(function(doy){
    doy = ee.Number(doy)
    var temp_date = date1.advance(doy.subtract(1),"day")
    var temp_img = collection.filterDate(temp_date,temp_date.advance(1,'day'))
    return temp_img.mean().set("system:time_start",temp_date.millis())
  })
  return day_imgs
}).flatten())
Map.addLayer(daily_data)
var chart = ui.Chart.image.series({
imageCollection:daily_data,
region:roi,
reducer:ee.Reducer.mean(),
scale:1113.2,
// xProperty:,
})
print(chart)

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Medie Mensili

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var point = ee.Geometry.Point([11.097849, 43.793234]);
var dataset = ee.ImageCollection('COPERNICUS/S5P/NRTI/L3_NO2')
          .filterBounds(point)
          .filterDate('2019-01-01', '2022-12-31')
          .select('NO2_column_number_density');
var months = ee.List.sequence(1, 12);
var start_year = 2019;
var start_date = '2019-01-01';
var end_year = 2022;
var end_date = '2022-12-31';
var years = ee.List.sequence( start_year, end_year);

var byMonthYear =  ee.FeatureCollection(
  years.map(function (y) {
    return months.map(function(m){
          var w = dataset.filter(ee.Filter.calendarRange(y, y, 'year'))
                    .filter(ee.Filter.calendarRange(m, m, 'month'))
                    .mean();
      var pointMean = w.reduceRegion({reducer:ee.Reducer.first(), geometry:point,scale:1000});  
      return ee.Feature(null).set("value",pointMean.get("NO2_column_number_density")).set("year",y).set("month",m);
    })
  }).flatten()
);

print("feature collection",byMonthYear);

Export.table.toDrive({collection:byMonthYear,description:"O3_signa"})

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