Water Quality Monitoring with Sentinel-2 and DeepSeek

// Define region of interest (Rif Mountains and Middle Atlas, Morocco)
var roi = ee.Geometry.Rectangle([-5.5, 34, -3.5, 35]);

// Filter Sentinel-2 SR data for the specified period and region
var dataset = ee.ImageCollection('COPERNICUS/S2_SR')
                  .filterDate('2023-06-01', '2023-09-30')
                  .filterBounds(roi)
                  .filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', 20));

// Print the number of images found
print('Number of Sentinel-2 images:', dataset.size());

// Function to mask clouds using the QA60 band
var maskS2clouds = function(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.
  var mask = qa.bitwiseAnd(cloudBitMask).eq(0)
      .and(qa.bitwiseAnd(cirrusBitMask).eq(0));
  return image.updateMask(mask).divide(10000);
};

// Apply cloud masking
var maskedDataset = dataset.map(maskS2clouds);

// Function to calculate NDWI
var calculateNDWI = function(image) {
  return image.normalizedDifference(['B3', 'B8']).rename('NDWI');
};

// Calculate NDWI for each image in the collection
var ndwiCollection = maskedDataset.map(calculateNDWI);

// Create a composite image (median NDWI over the time period)
var ndwiComposite = ndwiCollection.median();

// Visualization parameters for NDWI
var ndwiVisParams = {
  min: -1,  
  max: 1,  
  palette: ['red', 'white', 'blue']
};

// Add the NDWI composite to the map
Map.addLayer(ndwiComposite, ndwiVisParams, 'NDWI Composite');

// Center the map on the region of interest
Map.centerObject(roi, 9);

// Export the Chlorophyll-a estimation to Google Drive
Export.image.toDrive({
  image: /* Chlorophyll-a image from DeepSeek result */,
  description: 'Chlorophyll_a_Estimation',
  folder: 'GEE_Exports',
  scale: 10, // Adjust scale as needed
  region: roi,
  maxPixels: 1e13
});

// Export the Turbidity estimation to Google Drive
Export.image.toDrive({
  image: /* Turbidity image from DeepSeek result */,
  description: 'Turbidity_Estimation',
  folder: 'GEE_Exports',
  scale: 10, // Adjust scale as needed
  region: roi,
  maxPixels: 1e13
});