Progress in Community Radiative Transfer Model for Satellite Radiance Assimilation

Quanhua (Mark) Liu1,2, Paul van Delst1,3, Ming Chen1, David Groff1,3, Yong Chen2, Andrew Collard3, Sid-Ahmed Boukabara1, Fuzhong Weng4, John Derber3

1 Joint Center for Satellite Data Assimilation; 2 ESSIC, University of Maryland, College Park, MD3 NOAA/NCEP; 4 NOAA/NESDIS Center for Satellite Applications and Research;

1. IntroductionThe Community Radiative Transfer Model (CRTM), developed at the Joint Center for Satellite Data Assimilation, has been applied to the NOAA/NWS operational radiance assimilation in supporting of daily weather forecasting, to the NOAA Microwave Integrated Retrieval System for operational satellite products, and to international remote sensing community for remote sensing sensor calibration, air quality application, and others including projects at CICS/ESSIC.

The latest CRTM version 2.1.3, which is applicable for passive microwave, infrared and visible sensors. It supports all NOAA satellite instruments, NASA MODIS, and many foreign meteorological satellites.

3. CRTM Modules and Supported Sensors

4. CRTM Transmittance Model

7.1 Stratosphere Sounding Unit(SSU)

Forward model

SfcOptics(Surface Emissivity Reflectivity Models)

AerosolScatter(Aerosol Absorption

Scattering Model)

AtmAbsorption(Gaseous Absorption

Model)

CloudScatter(Cloud Absorption Scattering Model)

RTSolution(RT Solver)

Source Functions

public interfaces

CRTM Initialization

CRTM Clearance

Jacobian model

Tangent-linear model

Adjoint model

Molecular scattering

CRTM main modules

• The transmittance model is to compute atmospheric transmittance from absorbing gases

• In addition to ODAS model, a new transmittance model ODPS (Optical Depth in Pressure Space) has been implemented in version 2.

• Variable absorbing gases: H2O, CO2, O3, CO, N2O and CH4

4.1 Transmittance Model

7.3 SSMIS Radiance Assimilation for Hurricane Prediction

CRTM 2.1 Release

• CRTM was initially proposed to support primarily the JCSDA partners to assimilate satellite radiance data into global/regional forecast systems

• It is now also supporting the US satellite program developments through generating a high quality proxy data for algorithm tests, developments and integrations

• It has been used in the NOAA/NESDIS microwave sounding product system

• It can be used to generate the synthetic satellite radiances from NWP nature runs for observation system simulation experiments (OSSE)

• It is linked to other key projects such as climate reanalysis and satellite cal/val

Joint Center for Satellite Data Assimilation (JCSDA) Partner Organizations

2. CRTM

CRTM simulated IASI, AIRS and CrIS spectrum

SSU mission was started onboard TIROS-N in October 1978 ended onboard NOAA-14 in 2007.Using the CRTM, we removed the effects of atmospheric and cell CO2 for a long-term data record of stratospheric temperatures.SSU showed that stratospheric temperatures may gradually recovered after 1996.Microwave sound unit (MSU) data supported the finding.Liu, Q., and F. Weng, 2009: Recent stratospheric temperature observed from satellite measurements, SOLA, 5, 53-56, doi:10.2151/sola.2009-014.

Support more than 100 Sensors

GOES-R ABITIROS-N to NOAA-19 AVHRRTIROS-N to NOAA-19 HIRSGOES-8 to 14 ImagerGOES-8 to 14 sounder Terra/Aqua MODISMETEOSAT-SG1 SEVIRI

Aqua AIRS, AMSR-E, AMSU-A, HSB

NOAA-15 to 19 AMSU-A

NOAA-15 to 17 AMSU-B

NOAA-18, 19 MHS

TIROS-N to NOAA-14 MSU,

DMSP F13 to 15 SSM/I

DMSP F13,15 SSM/T1

DMSP F14,15 SSM/T2

DMSP F16-20 SSMIS

Coriolis Windsat

TiROS to NOAA-14 SSU

METOP-A IASI AMSUA, MHS, HIRS, AVHRR

FY-3 IRAS, MWTS, MWHS, MWRISNPP CrIS/ATMS/VIIRSAMSR2, AMSR-E, TMIothers

4.2 Specific Transmittance Model

• Zeeman-splitting effect into account for affected microwave channels

• Stratospheric sounder unit transmittance for accounting for onboard CO2 cell pressure leaking.

• NLTE Model

5. Aerosol and Cloud Models

Aerosols:Global Model, GOCART Dust, Sea Salt, Organic carbon, Black carbon, SulfateRegional Model CMAQ is under implementation.Aerosol are assumed to be spherical particles. Spheroid shape for dust is under consideration.

Clouds:Liquid, Rain, Snow, Ice, Graupel, and Hail

Non-spherical particles for ice cloud are used for Visible and IR bands.

FILTER

DETECTOR

CO

2 c

ell

atm

osp

heric

rad

iatio

n

Effect of non-spherical particles.Ding, et al. TAMU

6. Surface Emissivity and Reflectance

The surface is divided as Water, Land, Ice, and Snow.

• CRTM computes emissivity and reflectance internally.

• CRTM accepts user defined emissivity data.

• CRTM uses Ocean BRDF IR model. Other

BRDF is under development.

7. Applications

7.2 Monitoring Sensor Performance

Using the CRTM simulation, we identified that VIIRS M12 image striping over oceans at daytime was caused by the difference among 16 detectors.Liu, Q., C. Cao, and F. Weng, 2013: Striping in the Suomi NPP VIIRS Thermal Bands through Anisotropic Surface Reflection, J. Atmos. Oceanic. Technol., 30, 2478–2487. doi: http://dx.doi.org/10.1175/JTECH-D-13-00054.1 Strong absorption above 20 hPa for

NOAA-16 because of out-of-band.

The SSMIS measures radiances in 24 channels covering a wide range of frequencies (19 – 183 GHz) conical scan geometry at an earth incidence angle of 53 degrees maintains uniform spatial resolution, across the entire swath of 1700 km.

Satellite information contents:SSMIS brightness temperature varies asHurricane developed and degraded.Liu and Weng, 2006: GRL,V33, L06817

Surface minimum pressure (hPa)

Surface maximum wind (m/s) Forecasting time (hour)

Control Test Observation Control Test Observation

00 988.87 983.31 959.00 26.18 31.51 46.20 06 981.55 974.60 950.00 36.36 30.46 48.80 12 970.80 957.90 942.00 39.05 39.33 51.40 18 964.45 945.81 948.00 39.97 48.99 51.40 24 951.71 936.11 941.00 45.19 49.31 51.40 30 935.58 923.40 930.00 49.40 57.20 64.20 36 927.75 913.17 909.00 54.86 58.20 74.50 42 918.92 908.72 902.00 57.94 58.31 77.10 48 916.38 905.25 905.00 54.31 59.67 71.90

Impact studies. Control the operational result; Test using SSMIS radiance assimilations. Liu and Weng, 2006: GRL, V33, L22811.

CRTM 2.1.3 release is available from ftp.emc.ncep.noaa.govat jcsda/CRTM/REL-2.1.3

Using the CRTM IR BRDF model, simulations over oceans agree with measurements.

SSUZeeman effect:The O2 transition line is split into many sublines, which can change transmittance.

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

El Chichon

Mt Pinatubo

SSU 1

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

El Chichon

Mt Pinatubo

SSU 2

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1979 1982 1985 1988 1991 1994 1997 2000 2003 2006

EI ChichonMt Pinatubo MSU 4

5 hPa

15 hPa