def radianceFromTOA():
"""
calculate at-sensor radiance from top-of-atmosphere (TOA) reflectance
"""
# top of atmosphere reflectance
toa = mission_specifics.TOA(TimeSeries.image, TimeSeries.mission)
# solar irradiances
ESUNs = mission_specifics.ESUNs(TimeSeries.image, TimeSeries.mission)
# wavebands
bands = mission_specifics.ee_bandnames(TimeSeries.mission)
# solar zenith (radians)
theta = mission_specifics.solar_z(
TimeSeries.image, TimeSeries.mission).multiply(0.017453293)
# circular math
pi = ee.Number(3.14159265359)
# Earth-Sun distance squared (AU)
d = ee.Number(TimeSeries.day_of_year).subtract(4).multiply(
0.017202).cos().multiply(-0.01672).add(1)
d_squared = d.multiply(d)
# radiace at-sensor
rad = toa.select(ee.List(bands)).multiply(ESUNs).multiply(
theta.cos()).divide(pi).divide(d_squared)
return rad
def get():
altitude = AtmcorrInput.elevation.reduceRegion(\
reducer = ee.Reducer.mean(),\
geometry = TimeSeries.geom.centroid()\
)
return ee.Dictionary({
'solar_z':
mission_specifics.solar_z(TimeSeries.image, TimeSeries.mission),
'h2o':
Atmospheric.water(TimeSeries.geom, TimeSeries.date),
'o3':
Atmospheric.ozone(TimeSeries.geom, TimeSeries.date),
'aot':
Atmospheric.aerosol(TimeSeries.geom, TimeSeries.date),
'alt':
altitude.get('be75'),
'doy':
TimeSeries.day_of_year
})