ozone from gome data using neural network technique

Neural Network based Ozone ProfileRetrieval Using Combined UV/VI

and IR Satellite Data

Anton K. Kaifel, Jasmine Kaptur (ZSW),

Martin Felder (LRZ)

Center for Solar Energy & Hydrogen Research (ZSW), Stuttgart, Germany

Leibniz Computing Center (LRZ), Munich, Germany

ITSC-15, Oct. 2006, Maratea, Italy

Outline

1. Start with TOVS

2. NNORSY and Optimal Estimation (OE)

3. Approach for NNORSY

4. Local error estimation

5. Results of NNORSY-GOME/TOVS

6. Summary and future

Neural Network based Ozone Profile Retrieval Using CombinedUV/VIS and IR Satellite Data

ITSC-15, Oct. 2006, Maratea, Italy

Monthly mean values of56 WOUDC ground stationsalso used for TOMS validation

NNORSY-TOVS L3 (09/79 –12/02)

NNORSY-TOVS Total Ozone

global TOVS TOMSRMS: 9.1 D.U. 8.0 D.U.Bias: 2.0 D.U. -2.8 D.U.

NNORSY-NOAA-TOVS zonal mean 1987 - 2000

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n U

nit

s

ITSC-15, Oct. 2006, Maratea, Italy

Op

tim

al

Est

imati

on

x

O3 profile

p(x|y)p(y|x) p(x)

p(y)=

x

"a priori"

y

GOMEspectrum

y

x

… …

k(x,y)

collocated measurements

yx RTM

OptimalEstimation

z.B. FURM, OPERA, ...

NNORSY

~1 min/profile

~1 ms/profile (!)

NN

OR

SY

Co

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ari

son

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retr

ieval

ap

pro

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ITSC-15, Oct. 2006, Maratea, Italy

Overview NNORSY

operationalreal-time

processing

GOME profiles

Operation

trainingdata

neuralnetworktraining

randomdata

mixing

testdata

eval.data

networkparam.s

qualitycheck

Training

GOMETOVS N14

Level 1data

WOUDCsondes

collocatedspectra/ profiles

collocation

SHADOZsondes

SAGE, POAM, HALOE

profiles

collocation

collocation

Preprocessing

ITSC-15, Oct. 2006, Maratea, Italy

ozonesondes

test data set: 01/1996 – 07/2001, 12000 collocations

POAM III

SAGE II

HALOE

NNORSY: Collocation Example

ITSC-15, Oct. 2006, Maratea, Italy

training data

evaluationdata

y

t

y

t

hiddenlayer

weights w

o(yi)

outputvector

ti

targetvector

"learning process":minimize E=Σi(o(yi)-ti)2

Quality check by cross-validation

test data

y

t

yi

otherinput

param.s

+

inputvector

NNORSY (Neural Network Ozone Retrieval System)

stoppingpoint

Training and Test for NNORSY

ITSC-15, Oct. 2006, Maratea, Italy

NNORSY (Neural Network Ozone Retrieval System)

GOMEspectral

data

geolocation

meteorol. info

climatologicalpredictors

yi

Input data for neural network

NNORSY Input Parameters

270 – 325 nm (O3 Hartley & Huggins)380 – 385 nm (atmosph. window)598 – 603 nm (O3 Chappuis)758 – 772 nm (O2 → cloud info)SZA, SAAsensor scan angleLOS type (east, nadir, west)GEOS4 temperature profileLatitudeSeason and sensor age

HIRSMSU

ITSC-15, Oct. 2006, Maratea, Italy

TOVSTb

Example for NNORSY Ozone Retrieval

y

t

training data 1

y

t

training data 1

o

NNORSYretrieval

|o-t|

training data 2

error networktraining

Estimation of Local Retrieval Error

NNORSYerror estimation

ITSC-15, Oct. 2006, Maratea, Italy

NNORSY NN configurations: training/test

ITSC-15, Oct. 2006, Maratea, Italy

GM: GOMETV: TOVSTp: temperature profile

NNORSY NN configurations: profiles

ITSC-15, Oct. 2006, Maratea, Italy

GM: GOMETV: TOVSTp: temperature profile

NNORSY-GOME Single Ozone Profile I

ITSC-15, Oct. 2006, Maratea, Italy

NNORSY-GOME Single Ozone Profile II

ITSC-15, Oct. 2006, Maratea, Italy

Correlative Analysis: Artic

ITSC-15, Oct. 2006, Maratea, Italy

Correlative Analysis: 400 S / New Zealand

ITSC-15, Oct. 2006, Maratea, Italy

NNORSY-Climatology (TLLO): Time Series

ITSC-15, Oct. 2006, Maratea, Italy

NNORSY-Climatology (TllO): Single Profiles for Antarctic

ITSC-15, Oct. 2006, Maratea, Italy

NNORSY: Summary and Current

► 10 year NNORSY-GOME ozone profile data set

► comparison/validation with sonde/lidar/satellite and data assimilation

► Using NNORSY for setup of new ozone profile retrieval

MetOp RAO Meeting, May 2006, Frascati, Italy

► NNORSY-OMI for ozone profile retrieval

► NNORSY application to SCIAMACHY nadir

► Combining GOME with TOVS: small improvements in troposphere

► New dynamic ozone profile climatology available

NNORSY-MetOp: Future

► Total ozone column

► ATOVS, IASI, GOME, GOME+IASI

► Ozone profiles

► IASI, GOME, GOME+IASI

ITSC-15, Oct. 2006, Maratea, Italy