Seung-Hyun Hwang

Observation of secondary ozone peaks near the tropopause over the Korean peninsula associated with stratosphere‐troposphere exchange

[1] Vertical profiles of ozone partial pressure and temperature were obtained from ozonesonde measurements for 10 years from 1995 to 2004, over the midlatitude area at Pohang, Korea (36.02°N, 129.23°E), where stratosphere to troposphere exchange (STE) is very active. Secondary ozone peaks were observed in the upper troposphere/lower stratosphere at altitudes of about 14 km mostly in winter and spring. The 450 ozonesonde profiles were analyzed for this study together with satellite measurements from Halogen Occultation Experiment (HALOE) onboard the Upper Atmosphere Research Satellite (UARS). To compare with the satellite data sets, 188 HALOE data sets were archived over the period of 1993-2004 with extended locations for latitudes 32°N-40°N and longitudes of 120°E-135°E, which cover the Korean Peninsula region. The occurrence of secondary maxima in the upper troposphere is highly correlated with zonal wind speed and temperature enhancements. Most of these secondary peaks also were associated with stratosphere-troposphere exchange processes. The backward trajectory model, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) from National Oceanic and Atmospheric Administration (NOAA) was used to examine these transport events further. The frequency of the secondary ozone peak appearance was found to increase at a rate of 1.4% yr -1 and 2.5% yr -1 for the past 10 years in this region on the basis of the ozonesonde and HALOE observations, respectively.

Vertical O3 profiling and error analysis by UV radiometer onboard KSR-III

Ozone density profile over the Korean peninsula was obtained by UV radiometer onboard the KSR-III (Korea Sounding Rocket-III) launched in Nov. 2002 and compared with other observations from satellites and ozonesonde. Due to altitude limitations in this first test flight of the newly-developed system, the apogee of the rocket was still in the stratosphere. Most of the previous algorithm for the optical absorption technique assumed to have measurements out of the ozone layer but our situation provided an opportunity to consider an algorithm to retrieve the vertical profiles of O3 number density for the rocket flight whose apogee is still in the ozone layer. In measurements by using optical instruments, various error sources exist in characterizing optical properties of detectors and atmospheric parameters. The magnitude of errors are analyzed and estimated in various rocket soundings but their quantitative effects of error sources due to each parameter in the retrieval have not been investigated in detail yet. In this paper, the quantitative error effects on the retrieval algorithm are investigated with respect to the altitudes. It is worthwhile to investigate this error sources for the current sounding as well as to reevaluate the previous rocket sounding data. Among retrieval parameters, the most influential error sources are found to be the absorption cross section and the filter response function. +0.65 nm shift in filter response function or -0.55 nm shift errors in absorption cross section are found to result in 5% deviation on the total number density. Whereas the total number density profiles are not so sensitive to the Rayleigh scattering or the slant air column density assumed. The stray light effect of the interference filter was also investigated.