IAS METHOD FOR 2D DATA ANALYSIS ON PC's

CHAPTER 5: ANALYZE and ANELAP

Running ANALYZE & ANELAP

These two programs read an archive file and produce a variable-length ASCII file with information broken down by time, particle type (habit), and particle size. A second file with particle mass information may also be generated. Again, make sure the executable file (.EXE suffix) is in the current directory or path, and enter either

ANALYZE or ANELAP

The program asks for the 3-digit flight number, flt, from which it creates both input and output filenames. It first looks for an archive file with the name NEWflt.ARC. If not found, it attempts to open PMSflt.ARC. If still unsuccessful, it requests a file pathname from the user. Once a file has been located, ANALYZE prompts for the following information. ANELAP is similar, except where noted below.

1. Enter a "T" if you wish to analyze by time ranges; else "B" to select 2D buffer ranges.
2. Enter either a start and stop time period (HHMMSS) or a first and last buffer number, depending upon your response to step 1.
3. The program then asks for an averaging period, either in seconds or number of buffers. This is the only place where ANELAP differs from ANALYZE. ANELAP asks for an active probe duration interval. For example, if a value of 1.0 were entered, then statistics would be output whenever the cumulative probe active time had reached one second, whether this spanned several buffers or part of a buffer. Note that entering a non-positive value for either program means that the entire selected range will be averaged as one group.
4. Next a list of particle habits is displayed. Initially all non-artifact habits are set to be selected (highlighted on the screen). The user may keep or omit certain habits by specifying the ordinal number associated with that habit. (Each time the number is specified, its select/deselect value is reversed.) Totals for deselected habits will not appear in the output file(s). Also, to get only the totals line (All Habits) record to be output and avoid the individual habit lines, enter the negative value of the ordinal number associated with the All Habits category. This reduces the quantity of output while summing just those habits that the user highlighted.
5. At least one of two possible output files must be selected. By default, the concentration output file is selected. It may be deselected in a manner similar to the way in which habits were selected, and/or the mass concentration file may be chosen. The format for these files will be described shortly.
6. There are two different particle mass calculations which are stored in the archive files. One is referred to as "Andy's mass", the derivation of which is described in Chapter 2. The second mass is called spherical mass. It uses the particle's diameter and area ratio and treats the particle as something like a spherical droplet. The user must select one of these measures; often in warmer, more liquid environments, the spherical mass is thought to be more accurate, whereas Andy's mass is often chosen when graupel or other solid particles are anticipated.
7. If the user is generating a concentration file, he then has the option of including some concentration file description records at the start of the file itself. These lines describe the layout of the numeric data records which follow. (They are similar to the description in this document.) If the user is already familiar with the file structure, he will probably enter "N" to omit these descriptor records.
8. The program proceeds to read through the archive file for the time or buffer range which was requested. Records are output to appropriate files periodically depending on the value entered at step 3.
9. When finished with the range, the user is asked about continuing with another range or not. A "Y" reply branches back to step 1; a "N" response terminates the program.

CONC_flt.n and MASS_flt.n,

whereas those created by ANELAP are nearly the same, namely

CONCEflt.n and MASSEflt.n

Once again, flt is the 3-digit flight number and n is a sequential number beginning with 1. Note that each time either program is executed, the sequence starts over at 1. Any previously existing file by the same name will be overwritten! The value of n merely increments during the program when more than one time or buffer range (usually corresponding to a particular cloud penetration) is requested.

Layout of Mass File

Layout of Concentration File

Record type 1: Header record consisting of the following fields: flt #, # type 2 records (nsel), # habit records output per time/buffer interval (nout), # particle size categories (bins), bin increment (microns), midpoint value of bin 1 (microns).

Only the first three fields are generally of any interest to the user.

Record type 2: Names of habits analyzed and/or output during the file's creation. The record consists of an integer habit number followed by the name of the habit. The number of these records in this file equals the value of the 2nd field in record type 1 (nsel). If the habit number is prefixed with a minus sign, it means that there are no records for this individual habit, but the habit was included in the totals line for each output interval.

Record types 1 and 2 appear only once in the file. After that comes a sequence of one type 3 record followed by "nout" type 4 records. This sequence repeats, one set for each time/buffer interval that was in the start-to-end range. The description of these records is as follows:

Record type 3: Time fields. The interval start and stop times (HHMMSS) are followed by probe active time, pressure, temp, FSSP or JW liquid water, and 2D mass. (The mass values are in grams per cubic meter.) To distinguish the liquid water source and which mass calculation was used (Andy's or spherical), the JW and spherical 2d mass values are output as the negative of their value. The time values are integers; the rest are floating point numbers.

Record type 4: Frequency and concentration values. The layout is as follows: Habit #, # diams with non-zero counts (n), {diam 1, freq 1, conc 1}, {diam 2, freq 2, conc 2}, ..., {diam n, freq n, conc n}, {freq for all diams, conc for all diams} (Note: Neither the braces nor the commas appear in the data.)

The second field in this record tells how many sets of three values follow it. At the end, there are two totals values representing particle count and concentration values for all diameter sizes. The diameter values are floating point values, whereas the other numbers are integers. Concentration values are in number per cubic meter.

The records described above are terminated by a carriage return, line feed combination. Fields are separated with spaces. Sometimes the records are so long (especially All Habits) that when printed or displayed on the screen they wrap around and may appear to be several records. In actuality, they are each just one rather long record.

Introduction

Chapter 1 - Discussion of Probes

Chapter 2 - Particle Shadow Classification

Chapter 3 - PRELIM2D Program

Chapter 4 - TOUCH2D Program

References