README file for the ACCLIP 2022 aerosol, water vapor, and ozone balloon sounding data from Osan Airbase Republic of Korea Corresponding Authors: J. Douglas Goetz Laboratory for Atmospheric and Space Physics University of Colorado - Boulder doug.goetz@lasp.colorado.edu ORCiD: 0000-0003-0824-1215 Joowan Kim Department of Atmospheric Science Kongju National University, Korea joowan.k@gmail.com ORCiD: XXXX-XXXX-XXXX-XXXX Co-author: Lars Kalnajs Laboratory for Atmospheric and Space Physics University of Colorado - Boulder kalnajs@colorado.edu ORCiD: 0000-0003-2301-2461 ********* Disclaimer ************ The dataset provided in the file 'ACCLIP_Balloon_Osan_Final.nc'. Please contact the authors for additional information. ******** Data Set Description ******** This dataset is comprised of aerosol, water vapor, and ozonesonde balloon soundings conducted from Osan Airbase located in the Republic of Korea during the Asian Summer Monsoon Chemical and Climate Project (ACCLIP), August of 2022. There were eleven balloon flight days where up to three balloons were flown containing either combined payloads with a Handix Scientific Portable Optical Particle Spectrometer (POPS) and an En-Sci Cryogenic Frost Point Hygrometer (CFH), or single payloads with either a En-Sci ECC Ozonesonde (ECC O3), LASP Optical Particle Counter (LOPC) or a LASP Stratospheric Total Aerosol Counter (STAC). Each payload was equipped with a Intermet iMet-4-RSB radiosonde to measure state parameters, GPS position, and telemeter the instrument data to the ground at a rate of ~1 Hz. A complete timetable is found below with corresponding flight numbers: Date Approx. Launch Flight Instrument Ceiling (dd/mm/yy) Time(UTC) Name Payload (km) ------------------------------------------------------------------------ 03/08/22 05:00 OSN002 POPS/CFH 27.2 03/08/22 05:00 OSN003 ECC O3 32.2 05/08/22 04:00 OSN004 POPS/CFH 24.0 05/08/22 04:30 OSN005 LOPC 29.8 05/08/22 04:00 OSN006 ECC O3 33.2 12/08/22 04:30 OSN008 POPS/CFH 26.0 12/08/22 05:30 OSN009 STAC 30.5 12/08/22 04:30 OSN010 ECC O3 33.0 16/08/22 00:30 OSN011 POPS/CFH 26.0 16/08/22 02:00 OSN012 STAC 31.2 16/08/22 00:30 OSN013 ECC O3 32.9 18/08/22 05:30 OSN014 POPS/CFH 25.7 18/08/22 05:30 OSN015 ECC O3 33.0 19/08/22 01:30 OSN016 POPS/CFH 25.7 19/08/22 02:00 OSN017 STAC 30.5 19/08/22 01:30 OSN018 ECC O3 32.1 20/08/22 04:00 OSN019 POPS/CFH 31.8 20/08/22 05:00 OSN020 STAC 30.7 20/08/22 04:00 OSN021 ECC O3 32.6 21/08/22 02:00 OSN022 POPS/CFH 26.1 21/08/22 02:00 OSN023 ECC O3 31.3 23/08/22 05:00 OSN024 POPS/CFH 25.9 23/08/22 05:30 OSN025 LOPC 28.0 23/08/22 05:00 OSN026 ECC O3 30.9 25/08/22 01:30 OSN027 POPS/CFH 25.7 25/08/22 02:00 OSN028 STAC 31.1 25/08/22 01:30 OSN029 ECC O3 31.0 27/08/22 02:00 OSN030 POPS/CFH 26.1 27/08/22 04:30 OSN031 STAC 24.9 27/08/22 02:00 OSN032 ECC O3 30.2 All dual POPS/CFH balloon soundings were equipped with a 'turn-around' or 'descent' valve that was designed to vent lift gas from the balloon at a ceiling of 25 or 26 km. The descent valve was not fully operational on some POPS/CFH flights and therefore ascent was terminated at a burst altitude. For flights with a fully operational descent valve the descent portion of the flight should be considered to have the highest quality CFH water vapor mixing ratio data with the lowest degree of WV contamination from the balloon envelope and load line. The table below gives the availability of ascent and descent profiles for each CFH flight: Flight Ascent Descent Date Name Profile Profile ---------------------------------------- 03/08/22 OSN002 X X 05/08/22 OSN004 X 12/08/22 OSN008 X X 16/08/22 OSN011 X 18/08/22 OSN014 X X 19/08/22 OSN016 X X 20/08/22 OSN019 X 21/08/22 OSN022 X X 23/08/22 OSN024 X X 25/08/22 OSN027 X X 27/08/22 OSN030 X X The flight data is provided in a single NetCDF-4 file named 'ACCLIP_Balloon_Osan_Final.nc'. The file is grouped by flight date (see table 1) and sub-grouped by the flight number. Each flight sub-group contains 1 dimensional state parameters and GPS data from the iMet-4-RSB radiosonde and also instrument specific variables. For example, the iMet ambient temperature from ascent portion of flight OSN002 on flight day 03/08/22 would be found at the following path within the netCDF file: /Flightday_20220802/OSN002_Ascent/iMet_T. The variables in each sub-group are indexed by 'time', which is a unitless dimension. For plotting by UTC Time in seconds since 01/01/1970 use 'POSIX_time'. ******** iMet-4-RSB Variables ******** Short Name Long Name Unit ----------------------------------------------------------------------------- iMet_Alt GPS Altitude kilometers (km) iMet_Lat GPS Latitude decimal degrees North (dd.ddddd) iMet_Lon GPS Longitude decimal degrees East (dd.ddddd) iMet_SatN Number of GPS Satellites n iMet_P Ambient Pressure hectopascal (hPa) iMet_T Ambient Temperature Degrees Celsius (°C) iMet_Theta Potential Temperature Degrees Kelvin (K) iMet_RH Relative Humidity Percent w.r.t. liquid water iMet_WS Wind Speed meters per second (m/s) iMet_WD Wind Direction degrees from North imet_u East Velocity meters per second (m/s) imet_v North Velocity meters per second (m/s) ******** POPS Variables ******** Short Name Long Name Unit ----------------------------------------------------------------------------------------- POPS_Concentration Cumulative Number Concentration Number per cubic centimeter (#/cc) POPS_diameter Start diameter of size bins Nanometer (nm) Flag_POPS_Quality POPS Data Quality Flag 0=good; 1=bad; The POPS cumulative concentrations are provided as two dimensional data where the row dimension is 'time' or a unitless index as described above, and the column dimension is indexed by POPS_diameter. The POPS data was telemetered as 16 evenly log-spaced pulse signal bins, which correspond to particle diameter based on Mie theory. Using the theoretical Mie response curve for Polystyrene Latex Spheres (PSLs) each POPS bin boundary corresponds to the sizes found in the table below. These bin boundaries are subject to change based on assumptions about aerosol refractive index. Concentration values are given as the sum in #/cc from all size bins greater than or equal to that size bin. The 'good' quality flag indicates if the data point passed quality control based on inlet flow rate, noise level, and by visual inspection. 'Bad' quality data indicates problems with inlet flow or counting, or descent portions of the profile and is has been used used as a mask in the POPS_concentration variable. Box smoothing of the POPS concentration by at least 30 seconds is recommended to reduce noise. Channel Minimum Size (nm) Maximum Size (nm) ------------------------------------------------- 0 136.4 147.7 1 147.7 160.9 2 160.9 176.9 3 176.9 196.5 4 196.5 220.6 5 220.6 273.5 6 273.5 358.7 7 358.7 474.7 8 474.7 559.5 9 559.5 751.7 10 751.7 1031 11 1031 1329 12 1329 1636 13 1636 2096 14 2096 2624 15 2624 3302 ******** CFH Variables ******** Short Name Long Name Unit ----------------------------------------------------------------------------- CFH_WVMR Water Vapor Mixing Ratio Parts per million by volume (ppmv) CFH_RHi Relative Humidity Percent w.r.t ice Flag_CFH_Quality CFH Quality Flag 0=good; 1=unventilated; 2=contaminated Water vapor mixing ratio was calculated when the mirror condensate was assumed to be in the ice phase at mirror temperatures less than -15° C using the Goff and Gratch equation for the vapor pressure of ice (Murphy & Koop, 2005). At mirror temperatures greater than -15°C the mirror condensate was assumed to be in the liquid or super-cooled liquid phase and the vapor pressure was calculated using parameterizations derived in Murphy & Koop (2005). The relative humidity over ice (RHi), or ice saturation, was calculated with the Goff and Gratch parameterizations. The CFH water vapor mixing ratio has been processed to remove (set as NANs) observations that use the CFH Quality Flag 1 or 2. Oscillations due to the mirror heater feedback response to variations in frost layer thickness have been filtered using a 20 second box smooth. ******** ECC O3 Variables ******** Short Name Long Name Unit ----------------------------------------------------------------------------- O3_PP Ozone Partial Pressure Millipascal (mPa) O3_VMR Ozone Volume Mixing Ratio Parts per million by volume (ppmv) O3_Column Ozone Total Column Dobson Unit (DU) The processed ascent profile ozonesonde data is provided in partial pressure, volume mixing ratio and total column at ~1 Hz resolution. The total column ozone is calculated from the ground level to the flights burst altitude. Averaging to 100 m is recommended to account to account for errors due to the response time of the ECC Ozonesonde. For more information please contact Joowan Kim. ******** LOPC Variables ******** Short Name Long Name Unit ----------------------------------------------------------------------------------------- LOPC_Concentration Cumulative Number Concentration Number per cubic centimeter (#/cc) LOPC_diameter Start diameter of size bins Nanometer (nm) Flag_LOPC_Quality LOPC Data Quality Flag 0=good; 1=bad; The LOPC cumulative concentrations are provided as two dimensional data where the row dimensions is unitless 'time' and the column dimension is LOPC_diameter. There are 24 LOPC channels that are custom quasi-log-spaced size bins derived from a theoretical Mie response curve for PSLs. The table below provides the size bin boundaries. It should be noted that the 300-350nm channel encountered noise issues in both LOPC flights and therefore been removed. The LOPC cumulative concentration values are given as the sum in #/cc from all size bins greater than or equal to that size bin. The 'good' quality flag indicates if the data point passed quality control based on inlet flow rate, noise level, and by visual inspection. 'Bad' quality data indicates problems with inlet flow or counting, or descent portions of the profile, and is has been used used as a mask in the LOPC_concentration variable. Box smoothing of the LOPC concentration by at least 30 seconds is recommended to reduce noise. Channel Miniumum Maximum Size (nm) Size (nm) ------------------------------------------------- 0 300 350 1 350 400 2 400 450 3 450 500 4 500 600 5 600 700 6 700 800 7 800 900 8 900 1000 9 1000 1250 10 1250 1500 11 1500 1750 12 1750 2000 13 2000 2500 14 2500 3000 15 3000 4000 16 4000 5000 17 5000 6000 18 6000 8000 19 8000 10000 20 10000 12000 21 12000 16000 22 16000 24000 23 24000 30000 The ******** STAC Variables ******** Short Name Unit ----------------------------------------------------------------------------------------- STAC_Total_Concentration Number per cubic centimeter (#/cc) Flag_STAC_Quality 0=good; 1=bad; The STAC is a balloon-borne condensation particle counter that measures particles between 10nm and 10000 nm. The STAC total concentration variable is indexed by the 'time' dimension within the netCDF file. A forthcoming paper on the STAC instrument will be published by Matt Norgren in 2023-2024. For more information on the instrument please contact the authors. The 'good' quality flag indicates if the data point passed quality control based on inlet flow rate, noise level, and by visual inspection. 'Bad' quality data indicates problems with inlet flow or counting, or descent portions of the profile, and is has been used used as a mask in the STAC_Total_concentration variable. Box smoothing of the STAC concentration by at least 30 seconds is recommended to reduce noise.