RAMAN SCATTERING IN THE EARTH’S ATMOSPHERE

RUTGER VAN DEELENJOCHEN LANDGRAF, ILSE ABEN

Photo credit: NASA

Buys Ballot

Research School

2004

Satellite measurement of backscattered sunlight

Raman scattering features

Radiative transfer model

Model result

Application of the model

Summary

OUTLINE

Sun

Earth’s

atmosphere

Earth’s

surface

SATELLITE MEASUREMENT OF

BACKSCATTERED SUNLIGHT

GOME SCIAMACHY

OMI

Sun

Earth

GOME SOLAR & EARTH SPECTRUM

GOME REFLECTIVITY SPECTRUMClear sky, the Netherlands, 1995, 0.2 nm spectral resolution

GOME REFLECTIVITY SPECTRUMClear sky, the Netherlands, 1995, 0.2 nm spectral resolution

ozone

O2

O2O2

NO2H2O

veg

etat

ion

vegetation

GOME REFLECTIVITY SPECTRUMClear sky, the Netherlands, 1995, 0.2 nm spectral resolution

ozone

O2

O2O2

NO2H2O

veg

etat

ion

vegetation

Raman

ROTATIONAL RAMAN SCATTERING

Cabannes

96 % elastic

Raman

4 % inelastic

N2, O2

at 400 nm

ROTATIONAL RAMAN SCATTERINGS

ola

r ir

rad

ian

ce

sca

tte

red

rad

ian

ce wavelength

(ir)

rad

ian

ce

wavelengthsca

tte

red

rad

ian

ce wavelength

Sun

Earth

ROTATIONAL RAMAN SCATTERINGS

ola

r ir

rad

ian

ce

wavelength

sca

tte

red

rad

ian

ce wavelength

ROTATIONAL RAMAN SCATTERINGS

ola

r ir

rad

ian

ce

refl

ecti

vit

y

RADIATIVE TRANSFERRadiative transfer equation describing multiple scattering

extinction

coefficient

intensity

source functiondistance

along path

MODEL RESULT

Total inelastic

fraction

Reflectivity

Raman features can be used to get cloud top height

Less air, less filling in

Low

cloud

High cloud

MODEL APPLICATION

SUMMARY

Raman features are clearly visible in reflectivity spectra: can be as large as 20%

We have developed a radiative transfer model which takes Raman scattering fully into account

Raman features can be used to retrieve cloud top height

THANK YOU FOR YOUR ATTENTION

R.van.Deelen@sron.nl