DRAGON ADVANCED TRAINING COURSE IN ATMOSPHERE … · Iref(λ) Iocc(λ) OCCULTATION calibration free...

Day 3 Lecture 3 Retrieval techniques - Erkki Kyrölä 1

DRAGON ADVANCED TRAINING COURSE IN ATMOSPHERE REMOTE SENSING

Occultation and limb scatteringErkki Kyrölä

Finnish Meteorological Institute

1. Instruments2. Occultation: GOMOS inversion

3. Limb scattering: OSIRIS inversion4. Summary

5. References

Occultation: SAGE, MSX UVISI, GOMOS, SCIAMACHY

Limb: OSIRIS, SOLSE/LORE, SCIAMACHY, GOMOS

INSTRUMENTS

T(λ)= Iref(λ)Iocc(λ)

OCCULTATION

calibration free principle

GOMOS: Measured Sirius reference spectrum

GOMOS: Measured Sirius transmitted spectrum

GOMOS: Calculated Sirius transmissions

T(λ,z) = exp(− σ j (λ,T(z(s))ρ j∫∑ (z(s))ds) Beer-Lambert law

Occultation inversion is simple because...

But ...

Occultation inversion

sσ = cross section

ρ = number density

= temperatureT

Weak scintillations: intensity maxima and minima

Density fluctuation

Strong scintillations: multiple stars

Stellar occultations: dilution & scintillations

T(λ,z,t2)

T(λ,z,t1)

different times

Stellar occultations: chromatic time delay

Different colors different refraction angles

T(z,λ) = Tref Text

We can, however, write

Transmission from refractive effects can be estimated from ray tracing calculations (dilution, chromatic effects). In addition, we need photometer measurements to estimate the random part (scintillations).

GOMOS: Horizontal transmissions 5-100 km

O3 inmesosphere

O3 instratosphere

NO2 instratosphere

T(λ,z) = exp(− σ j (λ)N∑ j(z))

N j (z) = ρ j∫ (z(s))ds

Occultation inversion using Beer-Lambert: Two step

Spectral inversion

Vertical inversion

This separation is not true if cross sections depend on temperature. In these cases we can use iteration over spectral and vertical inversion or one-step inversion.

C = covariance matrixT = transmission vector (all wavelengths)N = column density vector (different constituents)

We aim to minimize

Solution by Levenberg-Marquardt algorithm

Spectral inversion

S(N) = (Tobs − Tmod (N))T C−1((Tobs − Tmod (N))

Aspects of spectral inversion in UV-VIS

• Linearization• Non-linear approach

• Spectrally global• Spectral windows

• Absolute cross sections• DOAS

6000500040003000Wavelength (Å)

Cross sections

Transmission components at 27 km

Rayleigh

aerosol

An example of LM iteration

red=model to be fittedblue =data

black=residual

Chi2 vs iteration number

GOMOS vertical inversion

2d21 d22

2d31 2d32 d33

⎢ ⎢ ⎢ ⎢ ⎢ ⎢

⎥ ⎥ ⎥ ⎥ ⎥ ⎥

Discretize N(z) = ρ∫ (z(s))ds

N = Kρ

where the kernel matrix is

Onion peel solution

d11d22 d21

Tikhonov regularization

• Data extraction• Datation•Geolocation (ECMWF+MSIS90)• Wavelength assignment• Spectrometer samples correction• Photometer data processing• Central band background estimation• Star spectra computation• Transmission computation• Products generation

GOMOS Level 1b

GOMOS level 1Raw data

Geolocation& ray tracing

Instrumentalcorrections

Photometerdata

Transmissiondata

Limbdata

ECMWFprediction/analysisMSIS90

Calibrationdatabase

GOMOS level 2

Crosssections

Spectralinversion

Local densitiesO3, NO2, NO3aerosols, AirT, H2O, O2

Verticalinversion

Line densities

Level 1transmissions

Dilution& scintillation

corrections

Level 1photometer

LIMB SCATTERING

OSIRIS radiances

Scattered limb radiances

Total radiance= single scattering + multiple scattering

I = Isun Tsun∫ (s)(ρa (s)σ a (λ)Pa + ρR (s)σ R (λ)PR )Tdet (s)ds + Ims

Single and multiple scattering

Difficulties in limb radiative transfer

• MS time consuming• Albedo• Clouds• Aerosols• Polarization• Raman scattering

Modified onion peeling method

M = Itotal

S(ρ) = RModel − RMeas[ ]T ⋅ C −1 ⋅ RModel − RMeas[ ]

Measured transferspectra:

Modelled transfer

spectra:

Robs(z,λ) = Iobs(z,λ)Iref (zref ,λ)

Rmod (z,λ) = Imodss (ρ, z,λ )

Imodref (ρref , zref ,λ)

tabulated

Minimize

with onion peel type inversion or with one-step inversion

An example of LM iteration at 32 km (LimbLab SS)

An example of LM iteration at 24 km (LimbLab SS)

Summary

DOAS with spectral windowsFlittner for limb scattering; 3 wavelengths

Occultation and limb scattering retrievals can be approachedwith similar methods. They are based on:

-non-linear approach-using relative quantities, not directly measured quantities-original cross sections-all wavelengths

Other methods

Difficulties : Aerosol modelling, scintillations, multiple scattering

ReferencesThis presentation has followed:

Kyrölä, E., E. Sihvola, M. Tikka, Y. Kotivuori T. Tuomi, and H. Haario, Inverse Theory for Occultation Measurements 1. Spectral Inversion, J. Geophys. Res., 98, 7367-7381, 1993.

Oikarinen, L., E. Sihvola, and E. Kyrölä, Multiple scattering radiance in limb-viewing geometry, J. Geophys. Res., 104, 31261-31274, 2000.

Auvinen, H., L. Oikarinen and E. Kyrölä, Inversion algorithms for limb measurements, J. Geophys. Res., 107, D13, 2001JD000407, ACH 7-1: 7-7, 2002

Reference search (free): http://adsabs.harvard.edu/abstract_service.htmltitle words: osiris gomos sciamachy msx solse loreabstract words: retrieval limb occultation

More references from

Numerical examples: GomLab and LimbLab

DRAGON ADVANCED TRAINING COURSE IN ATMOSPHERE … · Iref(λ) Iocc(λ) OCCULTATION calibration free...

Documents

Transcript of DRAGON ADVANCED TRAINING COURSE IN ATMOSPHERE … · Iref(λ) Iocc(λ) OCCULTATION calibration free...

Solar Occultation Flux measurements of NMVOCs

Effective Localization Crowdsourcing · Workflow λ Mark translatable strings, export λ Release string freeze λ Translator: VCS checkout λ Translate w/ specialized tools λ Get

Journal for Occultation Astronomy - IOTA-ES · the publisher of the Journal for Occultation Astronomy (JOA). By now, we realise that JOA is a successful follower of the former Occultation

THE BOOK OF OCCULTATION - Kitab Al-Ghaibahalmawaddah.info/bukuonline/download.php?file=THE+BOOK+OCCULTATION... · Chapter 1 DEDICATION Thishumbleandpettyandunworthyeffort,O’myMaster,O’Loveof

Occultation limb sounders: GOMOS

The Occultation of the Twelfth Imam

What’s up @ ET in January 2016 - Ethiopian Airlines · What’s up ET in anuary 1 2 Ethiopian Airlines Partners with IOCC Consulting Ethiopian Airlines and IOCC Consulting are now

2013 Annual Report of the IOCC Accessible Version

7 Radio occultation techniques for probing the ionosphere · Radio occultation techniques for probing the ... Radio occultation measurements of GPS carrier phases ... Radio occultation

SIR based Frequency Reconfigurable Antenna using Varactor ......c, L e 0.0179 λ 0 W p1 0.022 λ 0 L d 0.00163 λ 0 W s 0.00245 λ 0 L f 0.0408 λ 0 W t 0.0049 λ 0 L g, W f 0.0245

Λ * (1520) Photoproduction

WGM Pham Le Thao Nguyen, Best Woman IOCC 2012

GPS Radio-Occultation data (COSMIC mission)

Why Radiative Transfer? Introduction to Solar …zeus.colorado.edu/astr7500-toomre/Lectures/SolStelMag...Basic Radiative Transfer: Emission Emission j λ: I λ(s+ds)=I λ(s)+dI λ

Propagation Phenomena From GPS Occultation

Weak decay of 5 Λ He and 12 Λ C : experimental results

background using lunar occultation - arXiv

Occultation setup

Migdal and his theory in Jülich. - arXiv · 2018. 11. 6. · T λ ω−E λ+ iη (22) L λ = v2 λ −u λv λ u λv λ −u2 λ!; T λ = u2 λ u λv λ −u λv λ −v2 λ! (23)

APPROXIMATION OF FOURIER INTEGRAL … OF FOURIER INTEGRAL OPERATORS BY GABOR MULTIPLIERS 3 operators of the form (3) M af = Mχ ′,g,Λ a f = X λ∈Λ aλhf,π(λ)giπ(χ′(λ))g,