VLIDORT User's Guide

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unning the installation tests. Both the “gfortran” and “ifort” subdirectories of this subdirectorythemselves contain subdirectories “obsgeo” and “nstokes3” which contain results for tests usingthe observational geometry feature and “NSTOKES=3” tests (not shown in the figure). Objectand module files for the VLIDORT code are stored in the directories “obj” and “mod” (the“makefile” ensures this is done). As mentioned above, the VLIDORT source code is stored insubdirectories “vlidort_main” which contains the subroutines and “vlidort_def” which containsVLIDORT I/O type structure definitions along with the file “vlidort_pars.f90” of constants,dimensioning parameters and floating-point type definitions. The “docs” directory contains theVLIDORT user documentation, while directory “util” has VLIDORT package utilities. Finally,the “vsup” subdirectory contains the source code of VLIDORT supplements (currently theVBRDF and VSLEAVE supplements).Accompanying these subdirectories are the bash shell scripts “vlidort_run”, “vlidort_run_subset”and “vlidort_check”. These are used to run the installation tests and compare with archivedresults and will be discussed in section 4.3.4.2. Source code Directories4.2.1. vlidort_defThis directory contains the following VLIDORT I/O type structure definition module files:• vlidort_io_defs.f90• vlidort_inputs_def.f90• vlidort_outputs_def.f90• vlidort_sup_def.f90• vlidort_sup_brdf_def.f90• vlidort_sup_sleave_def.f90• vlidort_sup_ss_def.f90• vlidort_lin_io_defs.f90• vlidort_lin_inputs_def.f90• vlidort_lin_outputs_def.f90• vlidort_lin_sup_def.f90• vlidort_lin_sup_brdf_def.f90• vlidort_lin_sup_sleave_def.f90• vlidort_lin_sup_ss_def.f90• vlidort_pars.f90• vlidort_pars.f90_save• vlidort_pars.f90_Siewart2000• vlidort_pars.f90_vsleave_test4.2.1.1. File “vlidort_pars.f90”Module “vlidort_pars.f90” contains all symbolic dimensioning parameters (integers), plus anumber of fixed constants and numbers. This parameter file must be declared in every module(this includes the environment program). There is a set of basic dimensioning numbers which arepre-set; this basic set is listed in Table 4.1. All other dimensioning parameters are combinationsof this basic set, and are not described here.These basic dimensioning numbers should be altered to suit memory requirements and/or aparticular application. For example, if a calculation with clouds is required, allowance should bemade for a large number of scattering matrix expansion coefficients and quadrature streams54
(discrete ordinates), so that dimensions MAXSTREAMS and MAXMOMENTS_INPUT shouldbe increased as required. It is only necessary to go into the “vlidort_pars.f90” file in order tochange the dimensioning parameters. Re-compilation with the makefile is then carried out tobuild the executable.Table 4.1 Key parameters and dimensions in “vlidort_pars.f90”Name Type DescriptionMAXSTREAMS Dimension Maximum number of half-space quadrature streams.MAXLAYERS Dimension Maximum number of layers in the atmosphere.MAXFINELAYERS Dimension Maximum number of fine layers per coarse layer, requiredfor the exact single scatter ray-tracingMAXMOMENTS_INPUT Dimension Maximum number of input scattering matrix expansioncoefficients. Set to at least twice MAXSTREAMS.MAX_THERMAL_COEFFS Dimension Maximum number of thermal coefficients (2)MAX_SZANGLES Dimension Maximum number of solar zenith anglesMAX_USER_VZANGLES Dimension Maximum number of user-defined off-quadrature viewingzenith anglesMAX_USER_RELAZMS Dimension Maximum number of user-defined relative azimuth anglesMAX_USER_OBSGEOMS Dimension Maximum number of user-defined geometry angle tripletswhen using observational geometry mode.MAX_USER_LEVELS Dimension Maximum number of user-defined output levelsMAX_PARTLAYERS Dimension Maximum allowed number of off-grid (non layer boundary)output levels. This number should always be less thanMAX_USER_LEVELS.MAXSTOKES Dimension Maximum number of Stokes parametersMAX_DIRECTIONS Dimension Maximum number of directions (2), up/downMAX_BRDF_KERNELS Dimension Maximum number of BRDF kernelsMAX_BRDF_PARAMETERS Dimension Maximum number of BRDF parameters allowed per kernelMAXSTREAMS_BRDF Dimension Maximum number of azimuth-quadrature streams for BRDFFourierMAX_MSRS_MUQUAD Dimension Maximum number of zenith-quadrature streams for multiplescatter reflectanceMAX_MSRS_PHIQUAD Dimension Maximum number of azimuth-quadrature streams formultiple scatter reflectanceMAX_ATMOSWFS Dimension Maximum number of atmospheric JacobiansMAX_SURFACEWFS Dimension Maximum number of surface property JacobiansMAX_MESSAGES Dimension Maximum number of error messages for error handlingHOPITAL_TOLERANCE Constant If the difference between any two polar angle cosines is lessthan ε, L’Hopital’s Rule is invoked to avoid singularity.OMEGA_SMALLNUM Constant If any total layer single scattering albedo is within ε of unity,then its value will be reset to 1-ε . Current value 10 -15MAX_TAU_SPATH,MAX_TAU_UPATH,MAX_TAU_QPATHConstantsIf the solar (S), viewing (U) or quadrature (Q) stream opticalthickness exceeds the respective limit, then correspondingtransmittances will be set to zero. Current values all 32.In addition to the basic dimensioning parameters, “vlidort_pars.f90” also contains fixed numberssuch as π, 0.0, 1.0, etc…, some fixed character strings used for output formatting, and some fileoutput numbers. A number of critical physics numbers are specified in this file. In particular, note55
Page 1:
User’s GuideVLIDORTVersion 2.6Rob
Page 5 and 6: Table of Contents1H1. Introduction
Page 7 and 8: 1. Introduction to VLIDORT1.1. Hist
Page 9 and 10: Table 1.1 Major features of LIDORT
Page 11 and 12: In 2006, R. Spurr was invited to co
Page 13: corrections, and sphericity correct
Page 16 and 17: Matrix Π relates scattering and in
Page 18 and 19: m⎛ P⎞l( μ)0 0 0⎜⎟mmm ⎜ 0
Page 20 and 21: In the following sections, we suppr
Page 22 and 23: of the single scatter albedo ω and
Page 24 and 25: Here T n−1 is the solar beam tran
Page 26 and 27: ~ + ~ ~ (1)~ ~ + ~ ~ (2)~ ~ − ~ 1
Page 28 and 29: The solution proceeds first by the
Page 30 and 31: Linearizations. Derivatives of all
Page 32 and 33: For the plane-parallel case, we hav
Page 34 and 35: One of the features of the above ou
Page 36 and 37: L↑↑ ↑k (cot n −cotn −1)[
Page 38 and 39: Note the use of the profile-column
Page 40 and 41: βl,aer(1)(2)fz1e1βl+ ( 1−f ) z2
Page 42 and 43: For BRDF input, it is necessary for
Page 44 and 45: streams were used in the half space
Page 46 and 47: anded tri-diagonal matrix A contain
Page 48 and 49: in place to aid with the LU-decompo
Page 50 and 51: In earlier versions of LIDORT and V
Page 53: 4. The VLIDORT 2.6 package4.1. Over
Page 57 and 58: Table 4.2 Summary of VLIDORT I/O Ty
Page 59 and 60: Table 4.3. Module files in VLIDORT
Page 61 and 62: Finally, modules vlidort_ls_correct
Page 63 and 64: end program main_VLIDORT4.3.2. Conf
Page 65 and 66: $(VLID_DEF_PATH)/vlidort_sup_brdf_d
Page 67 and 68: Finally, the command to build the d
Page 69 and 70: Here, “s” indicates you want to
Page 71 and 72: The main difference between “vlid
Page 73 and 74: to both VLIDORT and the given VSLEA
Page 75 and 76: STATUS_INPUTREAD is equal to 4 (VLI
Page 77 and 78: 5. ReferencesAnderson, E., Z. Bai,
Page 79 and 80: Mishchenko, M.I., and L.D. Travis,
Page 81: Stamnes K., S-C. Tsay, W. Wiscombe,
Page 84 and 85: Table A2: Type Structure VLIDORT_Fi
Page 86 and 87: DO_WRITE_FOURIER Logical (I) Flag f
Page 88 and 89: USER_LEVELS (o) Real*8 (IO) Array o
Page 90 and 91: angle s, Stokes parameter S, and di
Page 92 and 93: DO_SLEAVE_WFS Logical (IO) Flag for
Page 94 and 95: 6.1.1.8. VLIDORT linearized outputs
Page 96 and 97: NFINELAYERS Integer Number of fine
Page 98 and 99: 6.1.2.4. VLIDORT linearized modifie
Page 100 and 101: The output file contains (for all 3
Page 102 and 103: The first call is the baseline calc
Page 104 and 105:
for a 2-parameter Gamma-function si
Page 106 and 107:
Remark. In VLIDORT, the BRDF is a 4
Page 108 and 109:
6.3.3.1. Input and output type stru
Page 110 and 111:
Table C: Type Structure VBRDF_LinSu
Page 112 and 113:
Special note regarding Cox-Munk typ
Page 114 and 115:
squared parameter, so that Jacobian
Page 116 and 117:
6.4. SLEAVE SupplementHere, the sur
Page 118 and 119:
is possible to define Jacobians wit
Page 120 and 121:
etween 0 and 90 degrees.N_USER_OBSG
Page 122:
6.4.4.2 SLEAVE configuration file c
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