CRTM Releases and Ongoing CRTM Development

Contributors: David Groff, Paul van Delst, Quanhua Liu, Andrew Collard, Emily Liu, Jim

Jung and Agnes Lim

May 2014, JCSDA Workshop

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Outline

• Forecast experiments for CRTM 2.1 releases• Bug fixes for CRTM release 2.1.3 and CRTM

User Support• Verification of CRTM Jacobians• CRTM release 2.2 development and testing• Action items for the next year

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Forecast experiments for CRTM 2.1 releases

A Summary of CRTM 2.1 Forecast Experiments

• CRTM 2.1.1 : Includes FASTEM5 capability, but does not account for anisotropic/diffuse downwelling reflection correction.

- Neutral forecast impact with application of FASTEM-1- Slightly negative forecast impact with application of

FASTEM-5

• CRTM 2.1.2 : FASTEM5 accounts for anisotropic/diffuse downwelling reflection with this release.

• CRTM 2.1.3 : An adjoint initialization bug fix to CRTM 2.1.2 was applied. The bug fix further improved the forecast benefit of applying the anisotropic/diffuse downwelling reflection correction.

EMC Subversion Seminar Series: 1. Getting Started. October 2012 5

FASTEM-5 No Reflection Correction

EMC Subversion Seminar Series: 1. Getting Started. October 2012 6

FASTEM-5 With Reflection Correction

EMC Subversion Seminar Series: 1. Getting Started. October 2012 7

Reflection Correction Impact

JCSDA DRT Quarterly Review April 23, 2014

Bug Fix Impact (AMSUA channel 1 Jacobians)

Water Vapor Jacobian ProfileTemperature Jacobian Profile

dTb/dT dTb/dq

1E-06 1E-03

Temperature JacobianDifference(CRTM_2.1.3 – CRTM_2.1.2)

Water Vapor JacobianDifference(CRTM_2.1.3 – CRTM_2.1.2)

Bug Fix Forecast Impact

---- CRTM 2.0.5---- CRTM 2.1.2---- CRTM 2.1.3

---- CRTM 2.0.5---- CRTM 2.1.2---- CRTM 2.1.3

---- CRTM 2.0.5---- CRTM 2.1.2---- CRTM 2.1.3

---- CRTM 2.0.5---- CRTM 2.1.2---- CRTM 2.1.3

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Bug fixes for CRTM release 2.1.3 and CRTM user support

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Surface Emissivity Updates

• Emily Liu demonstrated that the inclusion of clouds in first guess fields was increasing the magnitude of (O-B) differences for AMSUA surface sensitive channels

• Initially all input CRTM clouds were assigned as being non-precipitating.

• The CRTM team identified that the FASTEM5 diffuse downwelling reflection correction component was incorrectly being turned off for non-scattering clouds.

JCSDA DRT Quarterly Review April 23, 2014 12

Example Reflection Correction Off (Compliments of Emily Liu)

JCSDA DRT Quarterly Review April 23, 2014 13

Example Reflection Correction On (Compliments of Emily Liu)

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Surface Emissivity Changes (cont.)• Currently multiple stream CRTM calculations do not account for a

diffuse surface reflection component.

• We need to add non-zero off diagonal contributions into the surface scattering matrices that are applied in our scattering radiative transfer solver.

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CRTM User Support• CRTM 2.1 releases do not support surface emissivity jacobian

capabilities.

• We have identified the code modifications needed to add this capability.

• Modifications to support this capability have been performed in a CRTM experimental branch and delivered to the MIRS team.

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Verification of CRTM Jacobians

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Water Vapor Line Jacobians • Minimization problems associated with the experimental

assimilation of IASI water vapor line channels were reported to the CRTM team.

• To investigate this problem we used relevant example profiles to verify CRTM jacobians for IASI water vapor line channels.

JCSDA DRT Quarterly Review April 23, 2014 18

Water vapour jacobians in the CRTM• 3 Methods: CRTM ODPS, ODAS, and OSS

– ODPS: fixed pressure level, fitting coefficients derived for each layer– ODAS: absorber space, fitting coefficients are a function of pressure (vertically constrained)– OSS: selected monochromatic line-by-line calculation based on tables.

• IASI water vapor jacobians– “problematic” channel 3281 at 1468.5 cm-1 (left); “normal” channel 3295 at 1465.0 cm-1,

OSS H2OODPS H2OODAS H2OOSS T (for comparison)

X-axes scaling:x100 for left, x10 on right

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Jacobians and Model Input Resolution

• For HIRS channels 2 through 6, users reported that maximum temperature jacobians were realized at the top of atmosphere when applying NCEP regional coordinates.

Jacobians and Model Input Resolution Temperature Jacobians

HIRS Channel 4 Jacobians

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Jacobians and Model Input Resolution ∆P

Jacobians and Model Input Resolution

(Temperature Jacobians / LOG(∆P))

HIRS Channel 4 Temperature Jacobians

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CRTM release 2.2 development and testing

Scattering-Indicator Testing

• The code had to be rearranged to separate scattering dependent and scattering independent calculations.

• The CRTM’s main TL/AD tests reported inconsistencies associated with this rearrangement.

• A rewrite of the adjoint code in the relevant branch was performed, and all tests are now passing.

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Current Action Items• High Priority (REL-2.1.4 and others as needed)

– Apply the cloud fraction approach described in Geer et al article– Deliver surface emissivity Jacobian capability to MIRS team. (Completed)– Incorporate the overcast radiances capability into the trunk.– Add non-zero off-diagnonal quantities to surface reflection matrices for multiple stream

microwave calculations.• Others

– Update CRTM files to use netCDF. SpcCoeff completed. For the TauCoeff update, this also involves refactoring of the optical depth routines. Additionally, this will reintroduce the capability to use a single precision build of the CRTM for use with high resolution GSI at NASA.

– Continue with coefficient generation as they are requested.– Update the transmittance modeling software.– Investigate the SOI K-matrix failures for some microwave instruments using particular

compilers (this will also involve some code refactoring)– Modify RT arrays to be fully allocatable so they are contiguous in memory (a computational

speed issue).