A. Structure

We recommend the standard Ames file format, FFI=2310, for exchange of most multidimensional data files associated with the ICARTT study.
The FFI descriptor is: FFI 2310; two real independent variables, one unbounded and one bounded with its number of values, base value, and constant increment defined in the auxiliary variable list; primary variables are real; auxiliary variables are real.

The file structure (pseudocode) described by the Ames format document looks like this:

NLHEAD 2310
ONAME
ORG
SNAME
MNAME
IVOL NVOL
DATE RDATE
DX(2)
[ XNAME(s) ] s=1,2
NV
[ VSCAL(n), n=1,NV ]
[ VMISS(n), n=1,NV ]
[ VNAME(n) ] n=1,NV
NAUXV ............first 3* auxil. var. are NX(m,1),X(1,m,1),DX(m,1)
[ ASCAL(a), a=1,NAUXV ]
[ AMISS(a), a=1,NAUXV ]
[ ANAME(a) ] a=1,NAUXV
NSCOML
[ SCOM(k) ] k=1,NSCOML
NNCOML
[ NCOM(k) ] k=1,NNCOML
[ X(m,2) NX(m,1) X(1,m,1) DX(m,1) ( A(m,a), a=4**, NAUXV ) ]
[ V(i,m,n), i=1,NX(m,1) ] n=1,NV

Let’s break it down line-by-line:

The first 7 lines are identical to FFI 1001 file type and described in Section 3B.

DX(2): this is the sampling interval for the unbounded independent variable (e.g., UTC); the same details/restrictions apply as they do to the sampling interval in FFI 1001 file type.

[ XNAME(s) ] s=1,2: here you list the names for the 2 independent variables starting with the bounded variable (e.g., GeoAltitude), then the unbounded variable (e.g., UTC).

NV: represents the total number of Primary variables. Primary variables are arrays.

[ VSCAL(n), n=1,NV ] : analogous to FFI 1001 file type.
[ VMISS(n), n=1,NV ] : analogous to FFI 1001 file type.
[ VNAME(n) ] n=1,NV: analogous to FFI 1001 file type.

NAUXV ............first 3* auxil. var. are NX(m,1),X(1,m,1),DX(m,1): total number of Auxiliary variables; where the first 3* are:
- NX(m,1) = Dimension; total number of values for Primary variables (i.e., array size)
- X(1,m,1) = Base value of the bounded variable.
- DX(m,1) = Increment value of the bounded variable.

Therefore, we can now construct ALL bounded variable’s values using:
X(i,m,1) = X(1,m,1) + (i-1) * DX(m,1) for i=1,NX(m,1). Simplified,
Value[i] = baseValue + (i * increment), where i=0 to arraySize-1

Note: if the bounded variable’s increment is non-constant, then enter –9’s (missing flag) for its base and increment values. In this case, the FIRST Primary Variable (array) should contain the bounded variable values.

[ ASCAL(a), a=1,NAUXV ]: analogous to Primary variables description (see above)
[ AMISS(a), a=1,NAUXV ]: analogous to Primary variables description (see above)
[ ANAME(a) ] a=1,NAUXV: analogous to Primary variables description (see above)

NSCOML
[ SCOM(k) ] k=1,NSCOML: analogous to FFI 1001 file type

NNCOML
[ NCOM(k) ] k=1,NNCOML: analogous to FFI 1001 file type

The Data Section:
[ X(m,2) NX(m,1) X(1,m,1) DX(m,1) ( A(m,a), a=4**, NAUXV ) ]
[ V(i,m,n), i=1,NX(m,1) ] n=1,NV

Each data record contains UTC, Auxiliary and Primary variables:
- Each data record always begins with UTC; the next 3* values after UTC are the Primary variable(s)’ dimension, the bounded variable base value, and the bounded variable increment value, respectively. The values after that thru NAUXV are the rest of the Auxiliary variables. All of these values from UTC to NAUXV are listed on one line.
- The next line lists ALL values (in array) for the first Primary variable.
- Then, the line after that lists ALL values for the second Primary variable; and so on until ALL “NV” Primary variables are listed. Please remember there is no limit on the number of char's per line; so DO NOT break arrays into multiple lines. The array size must be the same for all Primary variables.

* {when Start/Stop/Mid-point Sampling Intervals used: the 3* becomes 5 and variables are listed as follows: UTC_Stop, UTC_Mid, NX(m,1), X(1,m,1), DX(m,1)}.

** {when Start/Stop/Mid-point Sampling Intervals used: the 4** becomes 6}.

In the Header Normal Section, please include all KEYWORD/VALUE pairs. If LODs are to be used, then try to use one ULOD_FLAG and one LLOD_FLAG for all parameters. Also to remember that LODs DO NOT apply to Independent variables.

For example (Header Normal Section):

ULOD_FLAG: -7777 (i.e., ALL parameters will use –7777 for their ULOD_FLAG)
ULOD_VALUE: ulod_Vi-2, ulod_Vi-1; ulod_Vi; ulod_Vi+1; ulod_Vi+2; ulod_Vi+3; . . . . ; ulod_Vn-1; ulod_Vn
[where,
{if Start/Stop/Mid-point Sampling Intervals used, then enter N/A; N/A; for UTC_Stop and UTC_Mid (i.e.: ulod_Vi-2;ulod_Vi-1= NA;NA;)}
ulod_Vi = ULOD_arraySize (normally, this will be N/A;)
ulod_Vi+1 = ULOD_boundedVar_Base
ulod_Vi+2 = ULOD_boundedVar_Increment
ulod_Vi+3 = ULOD_NextAuxVar
.
ulod_Vn-1 = ULOD_BeforeLast_PRIMARY_VAR
ulod_Vn = ULOD_Last_PRIMARY_VAR
]

Use similar procedure for LLODs. Enter N/A for variables that do not use LODs.

Below are 2 examples for clarification.

EXAMPLE [Equal Intervals Sampling]
File name: AD_DC8_20040129_r0.ict

60 2310
PI: LASTNAME, FIRSTNAME
NASA Langley Research Center
DC-8 GSFC/LaRC Lidar aerosol scattering ratios and depolarization
SOLVE II-File For Testing
1 1
2004 1 29 2004 2 16
60
Geometric altitude of observation (km)
Time (UT seconds) from 00 hours on flight date
6
.0001 .001 .0001 1.E-9 1.E-9 .0001
-9999999 -9999999 -9999999 -9999999 -9999999 -9999999
Total Scattering Ratio,532nm=((aerosol+molecular backscatter)/(molecular backscatter))
Total Scattering Ratio,1064nm=((aerosol+molecular backscatter)/(molecular backscatter))
Aerosol Depolarization Ratio,532nm=((perpendicular aerosol backscatter)/(parallel aerosol backscatter))
Aerosol Backscatter Coefficient at 532 nm (1/km-sr)
Aerosol Backscatter Coefficient at 1064 nm (1/km-sr)
Log base 10 of molecular density used in analysis, #/cc
9
1.0 .001 .001 1.0 1.0 .01 1.0 .01 .0001
-999 -99999 -999 -9999 -99 -9999 -999 -9999 -999999
Number of altitude levels
Geometric altitude (km) at which data begins
Altitude increment (km)
Profile number, starting at 0
North latitude (degrees)
Latitude (minutes)
East Longitude (degrees)
Longitude (minutes)
Molecular depolarization ratio (dpolM=(perpendicular aerosol backscatter)/(parallel aerosol backscatter))
8
Data products were interpolated onto a uniform vertical grid based on GPS
geometric altitude. The vertical resolution is 75 meters.
Molecular density profiles derived from the DAO data sets were used in
retrieval of the lidar data products.
Reanalysis of the data set for improvements in quality and resolution will
occur as funding permits. Researchers interested in using this data should
contact Chris Hostetler for the latest update (Chris.A.Hostetler@NASA.gov).
---------------------------------------------------------------------------
19
PI_CONTACT_INFO: Address: 325 Broadway, Boulder, CO 80305; email: Chris.A.Hostetler@NASA.gov
PLATFORM: NASA DC8
LOCATION: Lat, Lon, and Alt included in the data records
ASSOCIATED_DATA: N/A
INSTRUMENT_INFO: Molecular depolarization ratio
DATA_INFO: dpolM=(perpendicular aerosol backscatter)/(parallel aerosol backscatter)
UNCERTAINTY: N/A
ULOD_FLAG: -7777
ULOD_VALUE: N/A
LLOD_FLAG: -8888
LLOD_VALUE: N/A
DM_CONTACT_INFO: N/A
PROJECT_INFO: Test File; April 15 2004
STIPULATIONS_ON_USE: Use of these data requires PRIOR OK from the PI
OTHER_COMMENTS: N/A
REVISION: R0
R0: No comments for this revision.
UTC NumAlt GeoAltBeg AltIncre GeoAltAC ProfileNum N.LatDeg LatMin E.LonDeg LonMin MolDepRatio TScatRatio532[] TScatRatio1064[] AerDepRatio532nm[] AerBkScatCoef532[] AerBkScatCoef1064[] Log10_MolDensity[]
----------------------------------------------------------------------------
32385 10 11325 075 0 69 229 5 1140 156
.....10871 10868 10879 10902 10907 10876 10854 10860 10843 10839
.....1166 1174 1182 1183 1179 1175 1175 1178 1186 1189
.....-9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 159 164
.....33611 33085 33116 33579 33373 31866 30698 30549 29585 29128
.....3871 4026 4161 4121 3990 3856 3803 3824 3947 3981
.....188028 187977 187926 187875 187824 187772 187721 187670 187619 187568
32445 15 11325 075 1 69 703 4 3777 156
.....10835 10839 10861 10870 10886 10872 10851 10845 10829 10822 10799 10783 10774 10782 10780
.....1201 1210 1217 1218 1214 1213 1219 1219 1217 1220 1212 1212 1212 1213 1220
.....-9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 159 163 168 173 178 181 190
.....32207 31984 32447 32391 32584 31715 30597 30011 29093 28513 27395 26527 25939 25875 25521
.....4687 4858 4941 4911 4767 4695 4772 4704 4624 4614 4409 4345 4303 4261 4365
.....188026 187975 187924 187873 187822 187771 187720 187669 187619 187568 187517 187466 187415 187364 187313
32505 13 11325 075 2 69 1027 4 1834 156
.....10835 10839 10861 10870 10886 10872 10851 10845 10829 10822 10799 10783 10774
.....1201 1210 1217 1218 1214 1213 1219 1219 1217 1220 1212 1212 1212
.....-9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 159 163 168 173 178
.....32207 31984 32447 32391 32584 31715 30597 30011 29093 28513 27395 26527 25939
.....4687 4858 4941 4911 4767 4695 4772 4704 4624 4614 4409 4345 4303
.....188026 187975 187924 187873 187822 187771 187720 187669 187619 187568 187517 187466 187415
32565 0 11325 075 2 69 1027 4 1834 156

EXAMPLE [Start/Stop/Mid-point Intervals Sampling]
File name: AD_J31_20040129_r0.ict

62 2310
PI: LASTNAME, FIRSTNAME
NASA Langley Research Center
DC-8 GSFC/LaRC Lidar aerosol scattering ratios and depolarization
SOLVE II-File For Testing
1 1
2004 1 29 2004 2 16
0
Geometric altitude of observation (km)
Start_Time (UT seconds) from 00 hours on flight date
6
.0001 .001 .0001 1.E-9 1.E-9 .0001
-9999999 -9999999 -9999999 -9999999 -9999999 -9999999
Total Scattering Ratio,532nm=((aerosol+molecular backscatter)/(molecular backscatter))
Total Scattering Ratio,1064nm=((aerosol+molecular backscatter)/(molecular backscatter))
Aerosol Depolarization Ratio,532nm=((perpendicular aerosol backscatter)/(parallel aerosol backscatter))
Aerosol Backscatter Coefficient at 532 nm (1/km-sr)
Aerosol Backscatter Coefficient at 1064 nm (1/km-sr)
Log base 10 of molecular density used in analysis, #/cc
11
1.0 1.0 1.0 .001 .001 1.0 1.0 .01 1.0 .01 .0001
-999 -999 -999 -99999 -999 -9999 -99 -9999 -999 -9999 -999999
Stop_Time (UT seconds)
Mid_Time (UT seconds)
Number of altitude levels
Geometric altitude (km) at which data begins
Altitude increment (km)
Profile number, starting at 0
North latitude (degrees)
Latitude (minutes)
East Longitude (degrees)
Longitude (minutes)
Molecular depolarization ratio (dpolM=(perpendicular aerosol backscatter)/(parallel aerosol backscatter))
8
Data products were interpolated onto a uniform vertical grid based on GPS
geometric altitude. The vertical resolution is 75 meters.
Molecular density profiles derived from the DAO data sets were used in
retrieval of the lidar data products.
Reanalysis of the data set for improvements in quality and resolution will
occur as funding permits. Researchers interested in using this data should
contact Chris Hostetler for the latest update (Chris.A.Hostetler@NASA.gov).
---------------------------------------------------------------------------
19
PI_CONTACT_INFO: Address: 325 Broadway, Boulder, CO 80305; email: Chris.A.Hostetler@NASA.gov
PLATFORM: NASA DC8
LOCATION: Lat, Lon, and Alt included in the data records
ASSOCIATED_DATA: N/A
INSTRUMENT_INFO: Molecular depolarization ratio
DATA_INFO: dpolM=(perpendicular aerosol backscatter)/(parallel aerosol backscatter)
UNCERTAINTY: N/A
ULOD_FLAG: -7777
ULOD_VALUE: N/A;N/A;N/A;1e7;2e7;3e7;4e7;5e7;6e7;7e7;8e7;9e7;10e7;11e7;12e7;13e7;14e7
LLOD_FLAG: -8888
LLOD_VALUE: N/A; N/A;N/A;.1;.2;.3;-.4;.5;.6;.7;.8;.9;.10;.11;.12;.13;.14
DM_CONTACT_INFO: N/A
PROJECT_INFO: Test File; April 15 2004
STIPULATIONS_ON_USE: Use of these data requires PRIOR OK from the PI
OTHER_COMMENTS: N/A
REVISION: R0
R0: No comments for this revision.
UT_Start UT_Stop UT_Mid Num_altitudes geo_alt_begin alt_increment geo_alt_aircraft Profile# N.Lat_deg Lat_min E.Lon_deg Lon_min Molecular_dep_ratio Total_Scat_Ratio_532nm[] Total Scat_Ratio_1064nm[] Aer_Dep_Ratio_532nm[] Aer_BkScatter_Coef_532nm[] Aer_BkScatter_Coef_1064nm[] Log10_mol_density[]
----------------------------------------------------------------------------
32385 32440 32400 10 11325 075 0 69 229 5 1140 156
.....10871 10868 10879 10902 10907 10876 10854 10860 10843 10839
.....1166 1174 1182 1183 1179 1175 1175 1178 1186 1189
.....-9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 159 164
.....33611 33085 33116 33579 33373 31866 30698 30549 29585 29128
.....3871 4026 4161 4121 3990 3856 3803 3824 3947 3981
.....188028 187977 187926 187875 187824 187772 187721 187670 187619 187568
32442 32505 32475 15 11325 075 1 69 703 4 3777 156
.....10835 10839 10861 10870 10886 10872 10851 10845 10829 10822 10799 10783 10774 10782 10780
.....1201 1210 1217 1218 1214 1213 1219 1219 1217 1220 1212 1212 1212 1213 1220
.....-9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 159 163 168 173 178 181 190
.....32207 31984 32447 32391 32584 31715 30597 30011 29093 28513 27395 26527 25939 25875 25521
.....4687 4858 4941 4911 4767 4695 4772 4704 4624 4614 4409 4345 4303 4261 4365
.....188026 187975 187924 187873 187822 187771 187720 187669 187619 187568 187517 187466 187415 187364 187313
32510 32560 32525 13 11325 075 2 69 1027 4 1834 156
.....10835 10839 10861 10870 10886 10872 10851 10845 10829 10822 10799 10783 10774
.....1201 1210 1217 1218 1214 1213 1219 1219 1217 1220 1212 1212 1212
.....-9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 -9999999 159 163 168 173 178
.....32207 31984 32447 32391 32584 31715 30597 30011 29093 28513 27395 26527 25939
.....4687 4858 4941 4911 4767 4695 4772 4704 4624 4614 4409 4345 4303
.....188026 187975 187924 187873 187822 187771 187720 187669 187619 187568 187517 187466 187415