C-Umkehr Retrieval Program Documentation Notes

by Edward W. Hare

Date of last update: March 1996

1.0 INTRODUCTION

This document is in support of the operational C-Umkehr retrieval program developed by Dr. Carl Mateer for use with the World Ozone Data Centre "raw" Umkehr data which contains data collected at 14 zenith angles. These "raw" Umkehr data profiles are the same data reported in the bi-monthly Environment Canada/WMO publication "Ozone Data for the World" (ODW) redbook.

The retrieval program called "MK2V4.EXE" produces a profile of ozone amounts representing 10 layers, from the troposphere (layer 1) to the upper atmosphere (layer 10). Original documentation on how to run this program along with the source code are also available. Refer to the directory: wodc/software/umkehr/Dobson.

For complete information regarding the retrieval approach refer to the following publication:

"A new Umkehr inversion algorithm" by C.L. Mateer and J.J. Deluisi (1992) in the Gotz Centennial issue of Journal of Atmospheric and Terrestrial Physics, Volume 54, number 5, pages 537-556.

2.0 DATA INPUT & PROCESSING

The MK2V4 program requires a data input file which meets the same requirements as the "raw" Umkehr data submission to the WOUDC. Refer to the document called "README.UMK" for a complete description of the fields. For convenience, an example is provided below.

Before these data are submitted to the retrieval program (MK2V4), a pre-processing of the data must be done using the program "DECODEV4.EXE". Output files from DECODEV4 are used as input to the retrieval program, therefore, it is imperative that the data being pre-processed is considered quality controlled and the format is correct.

Once the pre-processing is complete a report log is generated to assist in the further quality control of the data. Once the decode file is considered acceptable, the MK2V4 program may be run. Further output files are generated to assist in the quality assessment and interpretation of the data.

NOTE: Data processed and reported by the WOUDC may differ from the those data analysed independently due to further range and value checking.

3.0 STEPS TO RUN PROGRAMS

  1. Make sure to delete any versions of the unit6.prn files which are in the directory containing the programs. The FORTRAN compiler used for these programs requires this, otherwise a file error message will appear.
  2. Make sure that the input file adheres to the WODC standard input file format for Umkehr submission. Refer to the following example: 
    03112 071092 2100268 000 145 356 572 627 746 913 957 942 916 844 763 705 630  10
03112 071092 2300268 467 538 645 768 800 877 044 231 295 343 363 344 316 271  10
03112 071092 2400268 208 244 292 254 371 416 504 629 681 734 817 893 920 917  10
03112 211092 2100250 913 051 233 439 499 625 803 895 899 877 809 696 625 556  10
03112 211092 2300250 423 493 589 712 744 829 965 137 192 246 307 311 274 216  10
03112 211092 2400250 185 209 256 314 331 368 440 552 599 646 940 820 856 866  10
03112 261092 2100265 024 153 342 572 629 762 900 959 951 924 865 754 700 604  10
03112 261092 2300265 492 561 659 777 812 900 059 226 281 326 360 315 240 114  10
03112 261092 2400265 230 261 309 361 380 419 503 610 658 712 784 861 891 874  10
  3. Most data reported for the total ozone amount will have used the Vigroux scale prior to 1992 However, the WOUDC is encouraging stations to re-calculate these values using the Bass-Paur coefficients for the entire record to standardise these data. The software allows the choice of either Bass-Paur or Vigroux scaling.
  4. Run DECODEV4 and enter the appropriate filenames where required.
    Example: decodev4

  5. Examine the unit6.prn file for error flags.
  6. Run MK2V4 and enter the appropriate filenames where required.
  7. For a complete description of the data fields refer to the README.UMK help file.

4.0 FURTHER INFORMATION

Original documentation on how to run this program along with the source code are also available. Refer to the directory: wodc/software/umkehr/Dobson. Should you require further assistance in the operation of these programs, please contact the WOUDC at:

5.0 ACKNOWLEDGEMENTS

Carl Mateer has contributed many helpful suggestions and insights with respect to the use of this program. His contributions have assisted me in the writing of this document.