PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

SummaryACROSS

What did we proposeØ Perform sensitivity analyses for

proposed PACE instrument optionso OCIo OCI/OGo OCI+o OCI-3M

What did we accomplishØ Proposed PACE instrument sensitivity studies:

PACE ‘15

Project

→ NUV-SWIR radiance→ O2-A band radiance→ 1378, 2250 radiance→ VIS-SWIR polarization

o OCI 95 channels between0.35 μm and 2.13 μm

→

o OCI-3M 5 view angles between +/– 50 degrees

→

Ø Other satellite instrument sensitivity studies:

5 channels between0.41 μm and 2.25 μm

→

o OCI-2M OCI-3M but without polarization

→

o OCI-3M+ OCI-3M but more views & better accuracy

→

1% polarization accuracy→

Ø Compare RT computations for various atmosphere-ocean systems (AOS) o 5 AOS models o 2 altitudeso 4 wavelengthso >100 scattering angles

Ø Write manuscript about sensitivity analyses results

Ø Computations with 3 different RT codeso AOS models I, II, III o all altitudes, wavelengths, angleso 3 Stokes parameterso error ~ 1e-6 ΔP < 0.1%→

Ø 90+ page draft manuscript

Ø Update hydrosol modelo Involve input from PACE-IOP group

Ø Investigated 4 multi-parameter modelso ACROSS-I & -II models, c-model, IOCCG5

Ø 15+ page draft document

Other Ø Study aerosol height retrievals from O2-A data

Ø Theoretical and actual aerosol height retrieval studies using blue/UV polarization

relevant for PACE instrument design

relevant for PACE instrument design

Ø PACE ST polarimeter document

Dis

cuss

tom

orro

w

Ø manuscript in preperation

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

1. ACROSS

Less improvement in atmospheric correction

More improvement in atmospheric correction

Test increase in information in OCI+Polarimeter versus OCI alone

Motivation Polarization is an extremely useful tool to retrieve aerosol properties

Synthetic TOA data of I, Q, & U:

o Fine mode aerosol, τ = 0.2(re = 0.4 μm; ve=0.2; m=1.45

o Rough ocean surface(W = 7 m/s)

o Black water body

o μ0=0.8; μ=0.2, 0.4, 0.6, 0.8, 1.0 Δφ=60º & 120º

θ0 ≡ π – ϑ0

ocean

atmosphere

x

y

zsun

k0

φ0 = 0º

view

k

ϑ

φ

AOS system

Ø provided that it is measured with very high accuracies (0.2%–0.5%)

Source: Mishchenko and Travis, JQSRT 102:13,543-13,553 (1997)

Simulated aerosol retrieval from space-borne observation over ocean at 865 nm

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

Aerosol candidate models:

o Fine mode aerosol:τ = 0.01 – 0.4, Δτ = 0.01re = 0.01 – 0.8 μm, Δre = 0.01m = 1.3 – 1.7, Δm = 0.01ω = 0.78 – 1.00, Δω = 0.02ve = 0.2

>350,000 aerosol candidate models

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

Motivation

Aerosol candidate models:

o Fine mode aerosol:τ = 0.01 – 0.4, Δτ = 0.01re = 0.01 – 0.8 μm, Δre = 0.01m = 1.3 – 1.7, Δm = 0.01ω = 0.78 – 1.00, Δω = 0.02ve = 0.2

>350,000 aerosol candidate models

Source: Mishchenko and Travis, JQSRT 102:13,543-13,553 (1997)

ω=1.00 ω=0.98

ω=0.94 ω=0.92

optic

al th

ickn

ess

optic

al th

ickn

ess

refractive index refractive index

o radiance I, o 9 viewing angleso ΔI = 4%

o polarization Q/I and U/I,o 9 viewing angleso ΔP = 0.2%

Simulated aerosol retrieval from space-borne observation over ocean at 865 nm

Polarization is an extremely useful tool to retrieve aerosol properties Ø provided that it is measured with very high accuracies (0.2%–0.5%)

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

Motivation

o radiance I, o 9 viewing angleso ΔI = 6%

o polarization Q/I and U/I,o 9 viewing angleso ΔP = 0.8%

optic

al th

ickn

ess

optic

al th

ickn

ess

refractive index refractive index

ω=1.00 ω=0.98

ω=0.94 ω=0.92

Simulated aerosol retrieval from space-borne observation over ocean at 865 nm

Source: Mishchenko and Travis, JQSRT 102:13,543-13,553 (1997)

Polarization is an extremely useful tool to retrieve aerosol properties Ø provided that it is measured with very high accuracies (0.2%–0.5%)

Aerosol candidate models:

o Fine mode aerosol:τ = 0.01 – 0.4, Δτ = 0.01re = 0.01 – 0.8 μm, Δre = 0.01m = 1.3 – 1.7, Δm = 0.01ω = 0.78 – 1.00, Δω = 0.02ve = 0.2

>350,000 aerosol candidate models

Motivation

o radiance I, o 9 viewing angleso ΔI = 8%

o polarization Q/I and U/I,o 9 viewing angleso ΔP = 2.0%

optic

al th

ickn

ess

optic

al th

ickn

ess

refractive index refractive index

ω=1.00 ω=0.98

ω=0.94 ω=0.92

Simulated aerosol retrieval from space-borne observation over ocean at 865 nm

Source: Mishchenko and Travis, JQSRT 102:13,543-13,553 (1997)

Polarization is an extremely useful tool to retrieve aerosol properties Ø provided that it is measured with very high accuracies (0.2%–0.5%)

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

Aerosol candidate models:

o Fine mode aerosol:τ = 0.01 – 0.4, Δτ = 0.01re = 0.01 – 0.8 μm, Δre = 0.01m = 1.3 – 1.7, Δm = 0.01ω = 0.78 – 1.00, Δω = 0.02ve = 0.2

>350,000 aerosol candidate models

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

2015:

~1e-4

~1e-4

~1e-4

absolute difference

I

Q

UAOS system: molecular atmosphere above ocean surface

view angle0 20 40 60 80

view angle0 20 40 60 80

Polarization is an extremely useful tool to retrieve aerosol properties Ø provided that it is measured with very high accuracies (0.2%–0.5%)

Ø our forward RT computations need to match these accuracies!

Motivation

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

Results

θ0 ≡ π – ϑ0

ocean

atmosphere

x

y

zk0

φ0 = 0º

k

ϑ

φ

upper

lower

2 sun angles13 viewing angles

4 azimuth angles

TOA

SRF

>100 scattering geometries x 2 altitudes

λ = 350 nm, 450 nm, 550 nm, 650 nm

Polarization is an extremely useful tool to retrieve aerosol properties Ø provided that it is measured with very high accuracies (0.2%–0.5%)

I, Q, U → ΔP ≤ 0.1%

Ø our forward RT computations need to match these accuracies!

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

Results

10

–10

5

0

–5

–60–40 –20 0 20 40 60

dI (x106) dQ (x106) dU (x106) dP (%)

SRF, θ0=60° SRF, θ0=60° SRF, θ0=60° SRF, θ0=60°10

–10

5

0

–5

–60–40 –20 0 20 40 60

10

–10

5

0

–5

–60–40 –20 0 20 40 60

0.2

–0.2

0.1

0.0

–0.1

–60–40 –20 0 20 40 60

φ = 60° φ = 120°←║→ φ = 60° φ = 120°←║→ φ = 60° φ = 120°←║→ φ = 60° φ = 120°←║→

AOS-I (550 nm)

view angle view angle view angle view angle

Polarization is an extremely useful tool to retrieve aerosol properties Ø provided that it is measured with very high accuracies (0.2%–0.5%)

GSFCJPLNRL

UCSDUMBC

Ø our forward RT computations need to match these accuracies!

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

Results

10

–10

5

0

–5

–60–40 –20 0 20 40 60

dI (x106) dQ (x106) dU (x106) dP (%)

SRF, θ0=60° SRF, θ0=60° SRF, θ0=60° SRF, θ0=60°10

–10

5

0

–5

–60–40 –20 0 20 40 60

10

–10

5

0

–5

–60–40 –20 0 20 40 60

0.2

–0.2

0.1

0.0

–0.1

–60–40 –20 0 20 40 60

φ = 60° φ = 120°←║→ φ = 60° φ = 120°←║→ φ = 60° φ = 120°←║→ φ = 60° φ = 120°←║→

AOS-I (550 nm)

view angle view angle view angle view angle

view angle0 20 40 60 80

~1e-4

dI~1e-4

dQ

view angle0 20 40 60 80

~1e-4

dU

view angle0 20 40 60 80

o Benchmarked >magnitude bettero Satisfies polarization accuracy

Polarization is an extremely useful tool to retrieve aerosol properties Ø provided that it is measured with very high accuracies (0.2%–0.5%)

GSFCJPLNRL

UCSDUMBC

Ø our forward RT computations need to match these accuracies!

PACE: Radiative Transfer studies for Atmosphere-Ocean Systems

BackupSlides

Raman scattering

Summary

² Thepolarizedradiativetransferequationissolvedwithbothelasticandinelastic(Raman)scatteringincluded.

² Theangularradiationfieldcanbeprovidedatarbitraryverticallocationsinthecoupledatmosphereandoceansystems.

² Ramanscatteringcontributionisfoundtobesignificantinvisiblespectrumandclearwaters.