Get mean solar azimuth angle from Sentinel-2 L2A product

Question

I was coding in Google Earth Engine and one of the functions I run for cloud and shadow masking used the MEAN_SOLAR_AZIMUTH_ANGLE property.

shadow_azimuth = ee.Number(90).subtract(ee.Number(img.get('MEAN_SOLAR_AZIMUTH_ANGLE')))

I'm now trying to replicate what I did on GEE locally in Python using the Sentinel-2 L2A product from Copernicus. I was trying to find this value in the .SAFE product but I just don't seem to find it. Is this a value that comes with the Sentinel product or is this value calculated by GEE? And if it is, is there a way I can calculate it myself?

Answer 1

I think I found the answer. In the metadata file inside Granule, named MTD_TL.xml using this function it returns the azimuth and zenith angle.

import xml.etree.ElementTree as ET

def get_mean_solar_angles(metadata):
    tree = ET.parse(metadata)
    root = tree.getroot()
    
    tile_angles_element = root.find('.//Tile_Angles')
    if tile_angles_element is not None:
        mean_sun_angle_element = tile_angles_element.find('.//Mean_Sun_Angle')
        if mean_sun_angle_element is not None:
            zenith_angle = mean_sun_angle_element.find('./ZENITH_ANGLE').text
            azimuth_angle = mean_sun_angle_element.find('./AZIMUTH_ANGLE').text
        else: 
            print("No Mean Sun Angle was found")
            return
        return float(zenith_angle), float(azimuth_angle)