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Release Notes for MT_CKD

            AER Inc., 
            131 Harwell Avenue 
            Lexington,  MA  02421

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MT_CKD_2.5.2:

Date: January 2011

    - Added ‘if’ tests needed for speed improvements in monortm (K. E. Cady-Pereira, E.J. Mlawer)

    - Other software updates include:
	* In N2 pure rotation band, fixed incorrect indexing related to contribution from N2-O2 
	(E.J. Mlawer, A.E. Lipton, V.H. Payne)
        * Increased number of output points in all continuum modules to prevent possible truncation at
	high wavenumber end (E.J. Mlawer, S.A. Clough, C.H. Kohler)
	* Near-IR O2 continuum modified to allow for calculations over domains greater than 2000 cm-1; 
	needed by standalone continuum code (E.J. Mlawer, P. Hedelt)
	* O2 fundamental modified to correct 5 cm-1 shift (E.J. Mlawer, S.A. Clough, C.H. Kohler)
	* Rayleigh is now computed for IAERSL=5 (E.J. Mlawer, K.E. Cady-Pereira)

    - Updated historical information (E.J. Mlawer, V.H. Payne)

    - Corrected coding issue related to pure water vapor atmospheres in stand-alone continuum model (E.J. Mlawer).

    - Modified directory structure for source codes, makefiles, and documentation.

    - Added makefile system to compile the stand-alone continuum model.  Includes new platforms such as Windows and capability to easily add new platforms. 

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MT_CKD_2.5.1 (AER Internal Release Only):

Date: May 2010

      - Variables added to physical constants common block (J. Delamere) only in contnm.f (cntnm_progr.f not updated)

MT_CKD_2.5:

Date: January 2010

MT_CKD_2.5 continuum modifications included in this release are based on analyses of 
IASI, AIRS, and AERI measurements in the region past the bandhead of the CO2 
v3 band (~2385 cm-1):

      - Introduction of temperature dependence of carbon dioxide continuum absorption 
      from 2386-2434 cm-1 from IASI measurements (E.J. Mlawer and V.H. Payne)

      - Modification of carbon dioxide continuum coefficients from 2000-3000 cm-1 from 
      IASI and AERI (from ARM) measurements (E.J. Mlawer, V.H. Payne, and M.W. Shephard)

      - Modification of water vapor self continuum coefficients from 2000-3200 cm-1 from 
      IASI and AIRS measurements; fit based on near-IR studies of Bicknell et al. (2006) and 
      Fulghum and Tilleman (1991) (E.J. Mlawer and V.H. Payne)
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MT_CKD_2.4:  

Date: June 2009

Modifications to the water vapor continuum arise from new analyses of ARM measurements in the 
microwave and far-IR regions (S.A. Clough, J. Delamere, V.H. Payne, E.J. Mlawer)

- Analyses of measurements in the microwave are based primarily on the two-channel MWR (23.8 and 31.4 GHz) at SGP, 
  with supporting evidence from 150 GHz MWRHF measurements during the COPS campaign and from 170 GHz GVRP 
  measurements at SGP (Payne et al., 2009).
- Measurements in the far-IR were from the AERI_ext at the NSA site, in the time surrounding and including 
  the RHUBC-I campaign (Delamere et al., 2009).

Fixed an issue with the water vapor Jacobians in which the analytic Jacobians were dependent on the starting 
wavenumber (MT_CKD_2.3). (K.E. Cady-Pereira and S. Tjemkes)

Solved the issue of N2 Jacobians being included in the Jacobians generated for other 
molecules (MT_CKD_2.2) (S.A. Clough and M.W. Shephard)

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MT_CKD_2.1

Date: November 2007

CO2: Fundamental change in the lblrtm fourth function with consequent changes in continuum.
Bug fix impacting the nitrogen continuum in the 0-350 cm-1 region.      
             
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MT_CKD_2.0

Date: September 2007

CO2: Based on Hartmann P-Q-R line mixing.  Modification to v3 band based on AIRS data.   (July 2007)
H2O foreign modified in 250-550 cm-1 region based on analyses of nsa aeri_xr data.  (September 2007)	

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MT_CKD_1.3

Date: May 2006

Nu2 CO2: with P-R line mixing included; factor of 7 increase has been reduceed to 4.5

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MT_CKD_1.2

Date: 22 September 2004

MT_CKD_1.2 includes a modification to the collision induced absorption by 
N2 in the 0-350 cm-1 regime, Boissoles et al. (2003).

The structure of cntnm_progr.f has been altered somewhat to ensure closer
correlation betweem this continuum program and the continuum used in lblrtm.
The actual continuum module, contnm.f, is introduced into the present program
with an include statement.  The contnm.f module is that archived with lblrtm.

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MT_CKD_1.1

Date: 6 August 2004


MT_CKD_1.1 represents a modification of MT_CKD_1.0 for which the foreign
water vapor continuum in the 250 - 550 cm-1 range have been modified to
provide results consistent with CKD_2.4.1 in this spectral region.

The input water vapor mixing ratio is now interpreted as the mixing ratio 
with respect to DRY air.

The name of the output files have been modified slightly to
WATER.coeff and CNTNM.optdpt 

************************************************************************
MT_CKD_1.0


Date: 11 February 2003

This is the initial release of the MT_CKD water vapor continuum and
represents the  first recomputation of the entire self and foreign
broadened continuum since the original model was developed in the 
1980s.  This version of the continuum is implemented in the line-by-line
model LBLRTM v7.0 and will be utilized in all related AER Radiative 
Transfer models.

The MT_CKD continuum is based on a new formulation: The self and foreign
continuum models are each based on the contributions from two components:
a collision induced component and a line shape component.  This change in
perspective has resulted from the difficulty in developing a line shape
model based on sound physics that explains the magnitude of the increased
absorption in the intermediate wing over that provided by the impact 
approximation.

These two components are applied consistently to all water vapor lines 
from the microwave to the visible, and the results summed to obtain self 
and foreign continuum coefficients from 0-20,000 cm-1.  Eight and seven 
parameters are needed to specify the two components for the self and 
foreign continua, respectively, which are sufficient to generate the 
entire continuum spectrum over this spectral domain.  The ratio of the 
self continuum at 296 K to that at 260 K has been kept the same as in the 
CKD model.  The only temperature dependence for the foreign continuum 
arises from the radiation term as with CKD.  The MT_CKD model as with CKD, 
should be regarded as a semi empirical model with strong constraints 
provided by the known physics.

The data that have been used to develop the new continuum model has come 
predominantly from spectral atmospheric measurements.  Only cases for which 
the characterization of the atmospheric state has been highly scrutinized 
have been used.  This new model has been developed by E.J. Mlawer, 
D.C. Tobin and S.A. Clough building on the original CKD formulation; hence 
the name MT_CKD.


For this release of the continuum model, the stand alone program, 

                  cntnm_progr.f      

is being provided. 

The driver for this program enables input of the follwing pat variables: 
pressure, temperature path length and water vapor volume mixing ratio.  
A negative value for the pressure provides a default result from 
0 - 5000 cm-1 with P = 1013 mb, T = 296 k,  X (path) = 1 cm and vmr_h2o = 0.01.

In addition to the original version of ckd_0, there are three archived versions 
of ckd available with the release dates indicated:

ckd_2.4.2     2002_01        $Revision: 5.17

ckd_2.4.1     2000_04        revision:  5.12

ckd_2.2.2     1999_06        revision:  3.12

ckd_2.2       1996_03        revision:  3.7

ckd_0         1989

These models with associated readme files are contained in the directories 
associated with the continuum.  Information on the nature of the modifications 
is contained in the respective readme files.  The continuum module and associated 
continuum program (_program_) are very similar except that the latter includes a 
driver and a small modification has been made in 'SUBROUTINE CONTNM' to provide 
the appropriate interface.  The main substance of the code are data statements 
which are not only identical between continuum module and program, but up to this 
point are similar between the three evolutionary versions of the CKD continnum models.

Remarks on implementing the stand alone program are contained in
comments in the main progam: 'drcntnm' (driver for continuum).  The
program provides the following output files:

WATER.COEF - the mt_ckd_# self and foreign broadened water continuum coefficients.

CNTNM.OPTDPT - continuum optical depths for the defined path.


******   It should be noted that the MT_CKD water vapor continuum model
******   spans the spectral domain from 0 - 20,000 cm-1 (inf - 500 nm).

------------------------------------------------------------------------------------

VERSIONS OF THIS CONTINUUM MODEL ARE USED IN AER RADIATIVE TRANSFER MODELS INCLUDING 
LBLRTM, RRTM_LW, RRTM_SW AND MonoRTM.

EARLIER VERSIONS HAD BEEN INCLUDED IN FASCOD3, MODTRAN AND LOWTRAN7

------------------------------------------------------------------------------------

PRINCIPAL REFERENCES FOR THE MT_CKD WATER VAPOR CONTINUUM MODEL: 

Mlawer, M.J., D.C. Tobin, and S.A. Clough, A Revised Perspective on the Water Vapor 
Continuum:  The MT_CKD Model, in preparation for JQSRT, 2003.


PRINCIPAL REFERENCES FOR THE CKD WATER VAPOR CONTINUUM MODEL: 

Tobin, D. C., F. A. Best, P. D. Brown, S. A. Clough, R. G.
     Dedecker, R. G. Ellingson, R. K. Garcia, H. B. Howell, R. O.
     Knuteson, E. J. Mlawer, H. E. Revercomb, J. F. Short, P. F.
     van Delst, and V. P. Walden, Downwelling Spectral Radiance
     Observations at the SHEBA Ice Station: Water Vapor Continuum
     Measurements from 17-26 micrometer, J. Geophys. Res., 104,
     2081-2092, 1999.

Han, Y., J.A. Shaw, J.H.Churnside, P.D. Brown and S. A. Clough
     (1997):  Infrared spectral Radiance measurements in the
     tropical Pacific atmosphere, J. Geophys. Res.,102, 4,353-
     4,356.

Clough, S.A., The Water Vapor Continuum and its Role in Remote
     Sensing, in Optical Remote Sensing of the Atmosphere, Vol. 2,
     1995, OSA Technical Digest Series, (Optical Society of
     America, Washington, DC, 1995), pp 76-78.

Clough, S.A., F.X. Kneizys, E.P. Shettle, and G.P. Anderson (1986):
     Atmospheric Radiance and Transmittance:  FASCOD2, Sixth Conference
     on Atmospheric Radiation, Williamsburg, Virginia, May 1986.

Clough, S.A., R.W. Davies and R.H. Tipping (1983):  The line shape for
     collisionally broadened molecular transitions:  A quantum theory 
     satisfying the fluctuation dissipation theorem, Spectral Line
     Shapes, Editor:  K. Burnett, Walter de Gruyter, Berlin-New York
     1983; also AFGL-TR-82-0281.

Davies, R. W., R.H. Tipping, and S.A. Clough (1982):
     Dipole autocorrelation function for molecular pressure broadening:
     A quantum theory which satisfies the fluctuation dissipation
     theorem.  Phys. Rev. A, 26, 3378.

Clough, S.A., F.X. Kneizys, L.S. Rothman and W.O. Gallery (1981):
     Atmospheric spectral transmittance and radiance:  FASCOD1B.
     Proceedings of the SPIE 277, 152.
  
Clough, S.A., F.X. Kneizys, R. Davis, R. Gamache and R. Tipping:
     Theoretical line shape for H2O vapor:  Application to the
     continuum.  Atmospheric Water Vapor, edited by A. Deepak,
     T.D. Wilkerson and L.H. Ruhnke, 52, Academic Press, New York,1980.


_______________________________________________________________________Y

ADDITIONAL REFERENCES RELEVENT TO THIS CONTINUUM MODEL INCLUDE:


Boissoles, J., C. Boulet, R.H. Tipping, A. Brown and Q. Ma, 
     Theoretical CAlculations of the Translation-Rotation 
     Collision-Induced Absorption in N2-N2, O2-O2 and N2-O2 Pairs, 
     J.Quant. Spec. Rad. Transfer, 82,505 (2003).

Mate,B., C. Lugez, G.T. Fraser, and W.J. Lafferty (1999): 
     Absolute Intensities for the O2 1.27 micron continuum absorption,
     J. Geophys. Res., 104, 30,585-30,590. 

Clerbaux, C., P. Chazette, J. Hadji-Lazaro, G. Megie,J.-F. Moeller
     and S. A. Clough, Remote sensing of CO, CH4 and O3 using a
     space-borne nadir-viewing interferometer, J. Geophys. Res.,
     103, 18,999-19,013, 1998.

Mlawer, E.J., S.A. Clough, P.D. Brown, T.M. Stephens, J.C. Landry,
     A. Goldman and F.J. Murcray (1998):  Observed Atmospheric
     Collision Induced Absorption in Near Infrared Oxygen Bands.
     J. Geophys. Res., 103, 3859-3863.

Moncet, J.-L. and S.A. Clough (1997): Accelerated monochromatic
     radiative transfer for scattering atmospheres: Application of
     a new model to spectral radiance observations. J. Geophys.
     Res., 102, 21,853-21,866.

Mlawer,E.J., S.A. Clough.,P.D. Brown, Stephen, Landry, Goldman, & Murcray (1997):
     Observed  Atmospheric  Collision Induced Absorption in Near Infrared
     Oxygen Bands,  Journal of Geophysical Research.

Mlawer, E.J., S.J. Taubman, P.D. Brown, M.J. Iacono and S.A.
     Clough (1997):  Radiative Transfer for Inhomogeneous
     Atmospheres:  RRTM, a Validated correlated-k model for the
     longwave. J. Geophys. Res.,102, 16,663-16,682.

Lafferty, W.J., A.M. Solodov,A. Weber, W.B. Olson and J._M. Hartmann (1996):
     Infrared collision-induced absorption by N2 near 4.3 microns
     for atmospheric applications: Measurements and emprirical modeling, 
     Appl. Optics, 35, 5911-5917'

Iacono, M.J. and S.A. Clough  (1996): Application of infrared
     interferometer spectrometer clear sky spectral radiance to
     investigation of climate variability. J. Geophys. Res., 101,
     29,439-29,460.

Clough, S.A. and M.J. Iacono (1995): Line-by-Line Calculations of
     Atmospheric Fluxes and Cooling Rates II: Application to
     Carbon Dioxide, Ozone, Methane, Nitrous Oxide, and the
     Halocarbons. J. Geophys. Res., 100, 16,519-16,535.

Clough, S.A., C.P. Rinsland and P.D. Brown (1995):  Retrieval of
     tropospheric ozone from simulations of nadir spectral
     radiances as observed from space, J. Geophys. Res., 100,
     16,579-16,593.

Clough, S.A., M.J. Iacono, J.-L. Moncet (1992): Line-by-Line
     Calculation of Atmospheric Fluxes and Cooling Rates:
     Application to Water Vapor.  J. Geophys. Res., 97, 15761-
     15785.

Greenblatt,G.D., J.J. Orlando, J.B. Burkholder, and A.R. Ravishabkara (1990):
     Absorption Coefficients of Oxygen Between 330 and 1140 nm,   
     J. Geophys. Res., 95, 18577-18582. 

Kneizys, F.X., E.P.Shettle, L.W. Abreu, J.H. Chetwynd, Jr., G.P. 
     Anderson, W.O. Gallery, J.E.A. Selby, S.A. Clough and R.W. Fenn
     (1988):  USERS GUIDE TO LOWTRAN7, AFGL-TR-88-0177.
  
Borysow, A, and L. Frommhold, "Collision-induced rototranslational absorption 
     spectra of N2-N2 pairs for temperatures from 50 to 300 K", 
     The Astrophysical Journal, 311, 1043-1057, 1986.

Kneizys, F.X., E.P.Shettle, W.O. Gallery, J.H. Chetwynd, Jr.,
     L.W. Abreu,  J.E.A. Selby, S.A. Clough and R.W. Fenn (1983):
     ATMOSPHERIC TRANSMITTANCE/RADIANCE: COMPUTER CODE LOWTRAN6",
     AFGL-TR-83-0187. 

************************************************************************

                                                                                                                        
0  *****  CONTINUA mt_ckd_1.2                                                                         
                                                                                                                        
                                       H2O   SELF  (T)      0 - 20000 CM-1    mt_ckd_1.0                (December 2002) 
                                             AIR   (T)      0 - 20000 CM-1    mt_ckd_1.1                  (August 2004) 
                                       CO2   AIR            0 - 20000 CM-1    co2 nu2 increased * 7         (July 2002) 
                                       N2    SELF           0 -   350 CM-1    BORYSOW FROMMHOLD                         
                                             AIR         2085 -  2670 CM-1                                 (March 1998) 
                                       O2    AIR   (T)   1340 -  1850 CM-1                                 (March 1998) 
                                             O2/N2       7550 -  8486 CM-1                              (February 2000) 
                                             AIR         9100 - 11000 CM-1                                (August 1999) 
                                             O2         15000 - 29870 CM-1                                  (May  2000) 
                                             O2/N2      36000 -  >>>> CM-1    HERZBERG                                  
                                       O3    AIR         9170 - 24565 CM-1    CHAPPUIS / WULF                           
                                                   (T)  27370 - 40800 CM-1    HARTLEY HUGGINS                           
                                                        40800 - 54000 CM-1    HARTLEY HUGGINS                           
                                                                                                                        
                                                                                                                        
                                                                                                                        
                    H2O SELF HAS BEEN REDUCED IN THE 800-1200 CM-1 REGION                                 (01 SEPT 1985)
                    03       TEMPERATURE DEPENDENCE HAS BEEN CORRECTED                                     (01 MAY 1987)
                    02       (1390-1760) HAS BEEN REDUCED (FACTOR = 0.78)                                (07 MARCH 1990)
 ckd_1.0     2.2    H2O SELF HAS BEEN REDUCED IN THE 1100-1500 CM-1 REGION                               (01 APRIL 1993)
     "              H2O FOREIGN HAS BEEN REDUCED AT ~1300 CM-1 AND IN ALL THE WINDOW REGIONS             (01 APRIL 1993)
 ckd_2.1     3.3    H2O SELF HAS BEEN MODIFIED IN THE 700-1500 CM-1 REGION                                 (01 MAY 1994)
     "              H2O FOREIGN HAS BEEN MODIFIED IN THE ENTIRE 1200-2200 CM-1 SPECTRAL RANGE              (01 MAY 1994)
 ckd_2.2     3.7    H2O SELF HAS BEEN INCREASED 30% IN THE MICROWAVE REGION                                (09 FEB 1996)
     "              N2 COLLISION INDUCED PURE ROTATION BAND ADDED                                          (09 FEB 1996)
     "              O3 CHAPPUIS CHANGED TO VALUES FROM MODTRAN3                                            (09 FEB 1996)
 ckd_2.2.2   3.12   INTERPOLATION EFFECTS BETWEEN HARTLEY HUGGINS DATA AROUND 40800 CM-1                  (18 SEPT 1996)
 ckd_2.4.1   5.12   O2 COLLISION INDUCED FUNDAMENTAL BAND (1340-1850 CM-1) CHANGED TO THIBAULT ET AL., 1996 (MARCH 1998)
     "              N2 COLLISION INDUCED FUNDAMENTAL BAND (2085-2670 CM-1) CHANGED TO LAFFERTY ET AL., 1996 (MARCH 1998)
     "              H2O FOREIGN HAS BEEN MODIFIED IN THE 0-800 CM-1 AND 1200-2200 CM-1 RANGE BASED ON      (04 JUN 1999)
     "                       AERI-ER FROM SHEBA, TOBIN ET AL., 1998                                                     
     "              H2O SELF HAS BEEN INCREASED IN THE 0-200 CM-1 REGION                                   (04 JUN 1999)
     "              O2 COLLISION INDUCED BAND HAS BEEN ADDED  (9100 - 11000 CM-1); MLAWER ET AL. 1998      (16 AUG 1999)
     "              O2 COLLISION INDUCED BAND HAS BEEN CHANGED (7555 - 8486 CM-1); MATE ET AL. 1999        (10 FEB 2000)
 ckd_2.4.2   5.17   O2 COLLISION INDUCED BANDS HAVE BEEN ADDED (15000 - 29870 CM-1); GREENBLATT ET AL. 1990 (8 MAY 2000)
     "              The nu2 CO2 increased by a factor of 7: based on U  Wisc. AFWEX and AERI_xr at ARM NSA   (July 2002)
 mt_ckd_1.00 1.00   *********   The entire water vapor continuum has been revised   *********            (December 2002)
     "              *********   This continuum is based on a new line shape/collision induced formulation, mt_ckd  *** )
 mt_ckd_1.1         H2O foreign modified in the 250-550 cm-1 region; results now consistent with ckd_2.4.1 (August 2004)
 mt_ckd_1.2         Collision induced nitrogen 0-350 cm-1 increased (~1.35):  Boissoles at al., 2003    (September 2004)
                    ----------------------------------------------------------------------------------------------------

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