1. MDTERP MarylanD TErrestial Radiation Package A Narrow-Band Longwave Radiation Model with a Graphical User Interface Robert G. Ellingson and Ezra Takara Department of Meteorology University of Maryland College Park, MD 20742 Available after 1 April 1999 from http://metosrv2.umd.edu/~bobe/mdterp

2. MDTERP - Description Quantities Calculated Spectral radiance as F(wavenumber, nadir angle and altitude) Upward, downward and net upward fluxes and heating rates as F(wavenumber and altitude) Assumptions/Features Plane parallel, LTE, black surface and five angles in each hemisphere Molecular absorption by H2O, CO2, O3, CH4, N2O (1992 HITRAN) 10 cm -1 resolution from 0 to 3000 cm -1 Transmittances for for all gases fitted to LBLRTM (H2O - empirical model; others - Malkmus model) Fluxes and heating rates calibrated with LBLRTM As many as six cloud layers (black in current version) User control of input data, calculation levels, & cloud positions User selectable graphical and/or text output

3. MDTERP Uses a Graphical User Interface Available for Macintosh® Power PC platforms Platforms with Interactive Display Language ® (IDL ) and a Fortran 90 compiler Requirements Macintosh® - 12 MB RAM; 2 MB free disk space IDL - 10 MB RAM; 8 MB free disk space Tests to Date Macintosh - Power Mac 8100/80&100; several different G3 powered models IDL - DEC Alpha stations with Digital 4.0 UNIX

4. User selects the type of calculation, source of atmospheric data and clicks “Continue with Setup” Macintosh Use - Begin from Startup Menu AFGL - Air Force Geophysical Laboratory

5. Successive dialogs allow a user to select the source of data, levels of computation, and to specify the presence and location of clouds Macintosh - Default/AFGL Selection

6. Macintosh - Special Selection This dialog allows the user to select different profiles of temperature and gas concentration. It is possible to specify isothermal conditions and/or fixed concentrations of individual gases (including none).

7. Macintosh - Sensitivity Selection The user is presented with successive dialogs that allow the specification of conditions for two different cases. The model performs calculations for each case, and the interface allows a comparison of the results.

8. Macintosh - Perturbation Selection This dialog allows a user to add perturbations to the temperature and/or the gas concentrations used in a given profile. Either percentage or systematic offsets are permitted. The model performs calculations for each case, and the interface allows a comparison of the results.

9. Macintosh -When Calculations are Done, Use Menu Bar Use to select graphics of your choice Use to begin a new set of calculations Use to obtain text output Use to save text or graphics to directory of your choice

10. Macintosh - Flux and Cooling Rate Output Use to select spectral and altitude ranges, cloud levels, and case

11. Macintosh - Radiance Output Use to select direction, spectral and altitude ranges, cloud levels, and case

12. Macintosh - Radiance Spectral Distribution Use to graph spectral distribution of radiance at zenith (nadir) for different levels, cloud conditions, and case

13. Macintosh - Radiance Angular Distribution Use to plot angular distribution of radiance for different spectral intervals, levels, cloud conditions, and case

14. Macintosh - Cooling Rate Altitude and Spectral Distribution - Clough Diagram Use to plot spectral distribution of cooling rates for different cloud conditions and cases

15. Macintosh -Vertical Distribution of Fluxes and Cooling Rates Use to plot vertical distribution of fluxes and cooling rates for different spectral intervals, altitude ranges, cloud conditions and cases

16. Documentation/References Ellingson, R. G. and J. C. Gille, 1978: An infrared radiative transfer model: Part 1 - Model description and comparison of observations with calculations. J. Atmos. Sci., 35, 523-545. Warner, J., and R. G. Ellingson, 1997: A narrow band longwave radiation model based on parameters fitted to LBLRTM. Proceedings of the 1997 ARM Science Team Meeting. Warner, J., 1997:A New Longwave Radiation Model For Application to Atmospheric Problems. Ph.D. Dissertation, University of Maryland, 189 pp. Warner, J. X., and R. G. Ellingson, 1998: A new narrow band radiation model for water vapor absorption. Submitted to J. Atmos. Sci., Sept. 1998. Information regarding most of the techniques employed in the various calculations may be found in: