These sonde files contain the reprocessed sounding data as supplied by NOAA/CMDL in the original ASCII format. These files will be replaced by netCDF files in the future. --------------------------------------------------------------------------------- Description for the NOAA/CMDL - KFA Juelich sonde data files --------------------------------------------------------------------------------- All balloon packages had a Vaisala radiosonde and all but one package (31) an electrochemical concentration cell type ozone sonde. Half of all packages additionally had a frost-point hygrometer. The data files contain fileds for all possible data and give those, that were available from the package. Every data file contains 7 fields : 1 : Time after launch in minutes 2 : Pressure in mbar 3 : Altitude in km 4 : Temperature in deg C 5 : Relative humidity in % from the Vaisala Humicap sensor 6 : Ozone partial pressure in mPa from the ECC sensor 7 : Frost-point temperature in deg C from the frost-point hygrometer All but the frost-point field are ascent data (see comments). --------------------------------------------------------------------------------- Comments to the data fields : Field 2, Pressure : The pressure data from the Vaisala Radiosondes were corrected to an independently measured and well calibrated surface value, where this measurement was available (Flights 1 through 21). In the other flights the pressure was not surface corrected. The correction typically was less than 3 in 1000. Field 3. Altitude : The altitude was calculated by integrating the barometric equation, using the moist effective temperature. Field 4, Temperature : The temperature from the Vaisala thermocap sensor was corrected against the solar heating, using the radiation/ventilation correction algorithm, given by Vaisala. No surface correction was applied. Field 5, Relative Humidity : Though the Vaisala Humicap gives values up to the balloon ceiling, the profile was cut off, when it became unphysical, i.e. typically around 12 km or a frost-point temperature of -65 deg C. The reported values are not corrected to surface values. Field 6. Ozone partial pressure : The ozone partial pressure was corrected with an laboratory estimation of the background value in absence of ozone. This value was constant 0.06 uA for all flights. Field 7, Frost-point temperature : The frost-point temperature field contains mostly descent data, though in some cases gaps were filled by data from the balloon ascent. In the lower part of the profiles (typically below 5.5 km) the frost-point instrument gave no data. In these cases a value derived from the Vaisala relative humidity could be used to fill the gap. --------------------------------------------------------------------------------- The following table gives an overview over all balloon flights : Flight Date Time Location Ceiling Instruments [GMT] [km] 1 7 March 09:32 9 25'S, 159 58'E 17.0 H2O, O3 2 8 March 11:01 4 52'S, 162 38'E 5.9 O3 3 9 March 22:59 2 07'S, 169 35'E 31.6 O3 4 10 March 09:25 1 59'S, 171 00'E 6.5 H2O, O3 6 11 March 06:57 2 07'S, 175 20'E 31.8 O3 8 12 March 05:03 2 00'S, 178 46'E 26.3 H2O, O3 9 12 March 09:33 2 00'S, 179 30'E 31.0 O3 10 13 March 01:30 2 00'S, 178 02'W 30.1 H2O, O3 11 13 March 08:11 2 00'S, 176 57'W 32.3 O3 12 13 March 23:29 2 00'S, 174 46'W 23.5 H2O, O3 13 14 March 08:07 1 59'S, 173 39'W 32.2 O3 14 14 March 21:59 1 59'S, 171 23'W 29.1 H2O, O3 15 15 March 07:54 1 59'S, 169 43'W 27.8 O3 16 15 March 22:21 1 59'S, 167 07'W 29.5 H2O, O3 18 16 March 20:43 1 59'S, 162 55'W 32.4 H2O, O3 19 17 March 07:04 2 00'S, 161 11'W 29.5 O3 20 17 March 21:27 1 04'S, 159 03'W 28.1 H2O, O3 21 18 March 06:58 0 16'N, 158 25'W 31.4 O3 22 20 March 08:08 1 30'N, 157 12'W 32.4 H2O, O3 23 21 March 00:58 1 30'N, 157 12'W 31.0 O3 24 22 March 01:00 1 30'N, 157 12'W 31.0 O3 25 22 March 21:38 1 30'N, 157 12'W 26.9 H2O, O3 26 23 March 04:08 1 30'N, 157 12'W 33.3 O3 27 24 March 00:00 1 30'N, 157 12'W 26.4 H2O, O3 28 24 March 08:19 1 30'N, 157 12'W 33.1 O3 29 24 March 22:12 1 30'N, 157 12'W 26.8 H2O, O3 30 25 March 07:58 1 30'N, 157 12'W 33.9 O3 31 26 March 01:18 1 30'N, 157 12'W 27.1 H2O 32 26 March 04:44 1 30'N, 157 12'W 32.2 O3 =========================================================================================== Corrected version (V.2) of the CEPEX frost-point hygrometer data. _________________________________________________________________ On several of the CEPEX balloon-borne frost-point hygrometer water vapor soundings we encountered radio frequency interference (RFI) problems. This affected the analog digital converter on board the payload and resulted in an offset in the water vapor data. This offset produced consistently lower values than would be expected by other instruments, i.e. radiosondes in the middle troposphere, satellites in the lower stratosphere and the presumably unaffected hygrometer soundings. In the lab we could demonstrate, that this problem is unique to the combination of ozone sondes and frost-point hygrometers on the same payload and furthermore that this offset is largely independent of altitude. In these flights we lost the capability of giving absolute numbers for the amount of water vapor, since we had no independent way of determining the magnitude of this offset. However since this offset is largely independent of altitude, we used the stratospheric water vapor data from the HALOE instrument on board the Upper Atmospheric Research Satellite (UARS) to adjust the profiles of the affected soundings to give good agreement with HALOE at the 23 km level. The selection of 23 km is somewhat arbitrary, but has no influence on the adjustment, because the frost-point data show the same structure as the HALOE data. This adjustment is justified by several correlative measurements of HALOE and the frost-point hygrometer, in which these instruments show a good agreement in the range of overlap. Furthermore the profiles we believe to be unaffected by this RFI also show a good agreement with HALOE. We believe that under the circumstances this adjustment gives the best possible approximation to the real value. With an altitude independent offset in the A/D converter, the adjustment ranged between 1 and 2 degC in frostpoint in the better case and between 2 and 4 deg C in the worst case depending on the flight level. The ozone data were not affected by the RFI. The following table gives an overview of all frost-point soundings and indicates which of the soundings were affected by the RFI and were corrected in the described manner. Flight Date Time Location Ceiling Instruments Corrected [GMT] [km] 1 7 March 09:32 9 25'S, 159 58'E 17.0 H2O, O3 No 4 10 March 09:25 1 59'S, 171 00'E 6.5 H2O, O3 No 8 12 March 05:03 2 00'S, 178 46'E 26.3 H2O, O3 Yes 10 13 March 01:30 2 00'S, 178 02'W 30.1 H2O, O3 Yes 12 13 March 23:29 2 00'S, 174 46'W 23.5 H2O, O3 Yes 14 14 March 21:59 1 59'S, 171 23'W 29.1 H2O, O3 Yes 16 15 March 22:21 1 59'S, 167 07'W 29.5 H2O, O3 Yes 18 16 March 20:43 1 59'S, 162 55'W 32.4 H2O, O3 No 20 17 March 21:27 1 04'S, 159 03'W 28.1 H2O, O3 No 22 20 March 08:08 1 30'N, 157 12'W 32.4 H2O, O3 No 25 22 March 21:38 1 30'N, 157 12'W 26.9 H2O, O3 Yes 27 24 March 00:00 1 30'N, 157 12'W 26.4 H2O, O3 No 29 24 March 22:12 1 30'N, 157 12'W 26.8 H2O, O3 No 31 26 March 01:18 1 30'N, 157 12'W 27.1 H2O No For further information contact : Holger Voemel NOAA/CMDL/RE/CG1 325 Broadway Boulder, CO 80303 email : voemel@bogart.colorado.edu