Consultation on rrtatm. f

[Lambert-t]

Hello, I am new in the field of atmospheric science and I am interested in learning the RRTMG method recently. But it seems that there are some parameters in the rrtatm.f file that are not specified in the instructions, and I encountered problems while learning the source code. For example, Case1: In rrtatm.f, lines 176 are CALL LBLDAT (HDATE) and lines 177 are CALL FTIME (HTIME). It seems that I couldn't find LBLDAT and FTIME in the code

Case2: In line 576 of rrtatm.f,

read (IRD, 900) MODEL, ITYPE, IBMAX-B, NOZERO, NOPRNT, NMOL, IPUNCH, IFXTYP, MUNITS, RE, HSPACE, XVBAR, CO2MX, REF_LAT. 

But in rrtmg_lw_instructions do not seem to mention ITYP, IFXTYP and so on

Case3:The aerosol file mentioned the need for 16 bands of data, but I don't know how to obtain similar data.

I'm sorry, may I ask if you have more detailed instructions or other documents that can help me understand the corresponding, or some detailed run_example?

[mjiacono]

Thank you for your interest in the RRTMG model. The code can operate in two modes, either as a subroutine called from a wrapper code (not provided) or a host dynamical model, or it can run in column mode using the sample input files provided with the code. The rrtatm.f module was borrowed from another model (and adapted from yet another model) to provide the capability to read the example input files. Regarding your questions:

Case 1: Modules LBLDAT and FTIME are utilities stored in files in the /aer_rt_utils directory. The makefile will select the appropriate file for you system and compiler based on your setting of the variable PLATFORM in the makefile.

Case 2: Since RRTMG does not require all of the capabilities that were built into the earlier versions of rrtatm.f, it does not use some of the input parameters. The input instruction file for RRTMG_LW list sall of the input parameters that are needed for the model, and anything not listed can be ignored (even if it appears in read statements in the rrtatm.f source code).

Case 3: RRTMG allows aerosol properties to be provided separately for each band, but you can also approximate the aerosol effects by setting all bands to the same value or by providing separate aerosol optical property values for the infrared and UV/visible bands, which is often done by host prediction models.