D O B S T O O L PROGRAM FOR OPTIMIZING ZENITH BLUE AND ZENITH CLOUD OZONE MEASUREMENTS Content ------- 1. Introduction 2. Main menu 3. Calculation menu 3.1. Zenith polynomial 3.2. Cloud correction table 4. Recalculation menu 5. Print menu 6. Sort menu 7. Calculation of O3 from ZB and ZC data 7.1 Calculation of O3 from ZB data 7.2 Calculation of O3 from ZC data 1. Introduction ------------ DOBSTOOL is a software for optimizing DOBSON v.2.4 zenith blue (ZB) and zenith cloud (ZC) total ozone (O3) measurements . It has been applied to O3 data at the Hradec Kralove station using DS, ZB and ZC observations to compute new polynomial coefficients and cloud correction tables used in the calculation of the ZB and ZC ozone values. This program has also been created to re-process DOBSON v.2.4 data. Contact address : Martin Stanek Solar and Ozone Observatory Hvezdarna 456 500 08 Hradec Kralove 8 Czech Republic E-mail: stanek@chmi.cz 2. Main menu --------- The main menu includes the following items. - Calculation ... selection and opening of the submenu "Calculation" - Recalculation ... selection and opening of the menu "Recalculation" - Print ... selection and opening of the menu "Print" - Sort ... selection and opening of the menu "Sort" - F10 Menu ... selection of a menu by the cursor without a mouse - Alt-X Exit ... exit key - program termination - File: ... name of data file (OZmmyy.nnn) which is processed - Row: ... number of DS - ZB or ZC measurements 3. Calculation menu ---------------- The menu involves calculation of new zenith polynomials and cloud correction tables. 3.1. Zenith polynomial Command : Zenith polynomial Operation : Selection of near simultaneous DS and ZB measurements. Calculation of new coefficients of ZB polynomial and saving them in DOBSON.INI file. Entries : Instrument number Number of the Dobson spectrophotometer. Time interval (year) Specification of the first and the last year which is to be processed. Analysis Specification of the type of simultaneous DS and ZB measurements. Filter Selection of DS and ZB measurements with this restrictions - O3 value difference [%] Maximum value of (DS-ZB)/DS*100 - Time difference Maximum time difference between DS and ZB measurements - MU interval Setting of MU range - Date interval The first and last day and month which is to be processed Zenith polynomial Selection of zenith polynomial which is to be calculated. Path to data files Specification of a path to data files (C:\DOBSON\DATA). Path to DOBSON.INI file Specification of a path to DOBSON.INI file (C:\DOBSON). 3.2. Cloud correction table Command : Cloud correction table Operation : Selection of near simultaneous DS or ZB and ZC measurements. Calculation of new cloud correction tables and saving them in DOBSON.INI file. Entries : Instrument number Number of the Dobson spectrophotometer. Time interval (year) Specification of the first and the last year which is to be processed. Analysis Specification of the type of simultaneous DS or ZB and ZC measurements. Filter Selection of DS or ZB and ZC measurements with this restrictions - O3 value difference [%] Maximum value of (DS-ZB)/DS*100 - Time difference Maximum time difference between DS and ZB measurements Path to data files Specification of a path to data files (C:\DOBSON\DATA). Path to DOBSON.INI file Specification of a path to DOBSON.INI file (C:\DOBSON). 4. Recalculation ------------- Command : Recalculation Operations : - Recalculations of total ozone files created by DOBSON program in the past after re-initialization of all parameters except corrections of RN tables which are saved in the files (OZmmyy.nnn). Entries : Instrument number Number of the Dobson spectrophotometer. Time interval (year) Specification of the first and the last year which is to be processed. Path to data files Specification of a path to data files (C:\DOBSON\DATA). Path to DOBSON.INI file Specification of a path to DOBSON.INI file (C:\DOBSON). 5. Print ----- Command : Print Operations : - The menu involves printing of all input and output data of total ozone observations of a selected season. Entries : Parameter Mark a parameter which is to be printed. Instrument number Number of the Dobson spectrophotometer. Time interval Specification of the first and the last year which is to be processed. Path to data files Specification of a path to data files (C:\DOBSON\DATA). Output Flagging for display output (Screen), saving to a file (File) or printing (Printer) marked parameters. 6. Sort ---- Command : Sort Operations : - The menu involves selection of near simultaneous DS, ZB and ZC measurements. Entries : Instrument number Number of the Dobson spectrophotometer. Time interval (year) Specification of the first and the last year which is to be processed. Analysis Specification of the type of simultaneous DS and ZB or DS, ZB and ZC measurements. Filter Selection of DS, ZB and ZC measurements with this restrictions - O3 value difference [%] Maximum difference between two selected values - Time difference Maximum time difference between two selected values - MU interval Setting of MU range - Date interval The first and last day and month which is to be processed Values Mark a value which is to be printed. Path to data files Specification of a path to data files (C:\DOBSON\DATA). Output Flagging for display output (Screen), saving to a file (File) or printing (Printer) marked values. 7. Calculation of O3 from ZB and ZC data ------------------------------------- 7.1 Calculation of O3 from ZB data The calculation of O3 amounts from ZB data is accomplished through the application of an empirical polynomial relation. The relation used in DOBSON program has the following form: XZB = (A0 + A1*MU + A2*dN + A3*MU*MU + A4*dN*dN + A5*MU*dN + A6*MU*MU*dN + A7*MU*dN*dN + A8*MU*MU*MU + A9*dN*dN*dN) * EmpCor XZB ... total ozone [D.U.] MU ... relative air mass dN ... differences of NA-ND or NC-ND for wavelength pairs AD and CD respectively A0..A9 ... regression coefficients EmpCor ... empirical correction (ZB-AD or ZB-CD) 7.2 Calculation of O3 from ZC data The ZC ozone data are at first reduced in the same way as the ZB observations. For middle and low clouds the value of ozone must be decreased by amount from cloud correction table. 1. Low and middle clouds XZCAD = XZB*EmpCor - CCT*EmpCorOp XZCAD ... total ozone [D.U.] for AD wavelength pair XZB ... O3 amount from ZB-AD data EmpCor ... empirical correction (ZC-AD) CCT ... value obtained from the cloud correction table for AD wavelength pair EmpCorOp ... empirical correction for the opacity of clouds (from AD cloud correction table) XZCCD = XZB*EmpCor - CCT*EmpCorOp XZCCD ... total ozone [D.U.] for CD wavelength pair XZB ... O3 amount from ZB-CD data EmpCor ... empirical correction (ZC-CD) CCT ... value obtained from the cloud correction table for CD wavelength pair EmpCorOp ... empirical correction for the opacity of clouds (from CD cloud correction table) 2. High clouds XZCAD = XZB*EmpCor XZCAD ... total ozone [D.U.] for AD wavelength pair XZB ... O3 amount from ZB-AD data EmpCor ... empirical correction (ZC-AD) XZCCD = XZB*EmpCor XZCCD ... total ozone [D.U.] for CD wavelength pair XZB ... O3 amount from ZB-CD data EmpCor ... empirical correction (ZC-CD)