Evaluation of the Detection Ability of New Infrasound Networks Installed by Korea Meteorological Administration

The Korea Meteorological Administration (KMA) installed infrasound networks in Cheorwon and Yanggu. These networks have been operated for detecting infrasound generated from artificial explosions, such as those due to North Korea's nuclear tests, and from natural phenomena such as the volcanic eruption of Mt. Baekdu. Currently, the KMA is simultaneously performing infrasound analysis and seismic wave analysis to discriminate between natural and artificial earthquakes. To efficiently perform the discrimination and analysis of artificial earthquakes, three infrasound networks were expanded in the West Sea and northern Gyeonggi-do Gyodong-do, Paju, and Yeoncheon. In this study, 22 cases of artificial earthquake events that occurred in North Korea in January 2020 were analyzed to test the analysis capabilities of the three newly installed infrasound networks. The results of the analysis confirmed that the newly installed infrasound networks exhibited a higher infrasound detection rate than the existing Cheorwon and Yanggu infrasound networks. The Cheorwon and Yanggu observation networks are being planned for relocation and installation due to aging and poor site conditions. The use of the new infrasound network is expected to improve the detection rate and analysis accuracy with respect to artificial earthquakes. Furthermore, it is expected to enhance the detection capability of infrasound generated from various physical phenomena such as nuclear tests performed by North Korea and volcanic eruption of Mt. Baekdu.

Particulate Matter 10 (PM10) Is Associated with Epistaxis in Children and Adults

The impact of atmospheric concentration of particulate matter ≤10 μm in diameter (PM10) continues to attract research attention. This study aimed to evaluate the effects of meteorological factors, including PM10 concentration, on epistaxis presentation in children and adults. We reviewed the data from 1557 days and 2273 cases of epistaxis between January 2015 and December 2019. Eligible patients were stratified by age into the children (age ≤17 years) and adult groups. The main outcome was the incidence and cumulative number of epistaxis presentations in hospital per day and month. Meteorological factors and PM10 concentration data were obtained from the Korea Meteorological Administration. Several meteorological factors were associated with epistaxis presentation in hospital; however, these associations differed between children and adults. Only PM10 concentration was consistently associated with daily epistaxis presentation in hospital among both children and adults. Additionally, PM10 concentration was associated with the daily cumulative number of epistaxis presentations in hospital in children and adults. Furthermore, the monthly mean PM10 concentration was significantly associated with the total number of epistaxis presentations in the corresponding month. PM10 concentration should be regarded as an important environmental factor that may affect epistaxis in both children and adults.

Cloud, radiation, and surface heat flux simulations using Polar WRF with 3DVAR

<p>In the Arctic region, cloud is an important factor affecting surface radiation and heat flux. Despite the development of cloud microphysics schemes in the Polar WRF, clouds in the Arctic region still have uncertainties. In this study, the possibility of improving cloud simulations by using data assimilation (DA) and its effects on the enhancement of the forecast accuracy for surface fluxes and meteorological variables are evaluated. The experimental period is from 1 to 19 September 2017.</p><p>Forecasts from both the cold start experiment without DA and the warm start experiment with DA underestimated summer arctic clouds. When satellite radiances (AMSU-A and MHS) were assimilated at the analysis time, the distribution and quantity of water vapor were simulated more realistically, which results in the improvement of cloud simulations at the forecast time. As a result, the 25–30 hour forecast error of the downward shortwave (longwave) radiation flux in the warm start experiment which assimilated both conventional observations and satellite radiance data was reduced by 8.1% (12.7%), compared to that in the cold start experiment. The 25–30 hour forecast error of the upward latent (sensible) heat flux in the warm start experiment was also reduced by 7.8% (3.3%), compared to that in the cold start experiment. For the 2 m temperature and 10 m wind, the forecast error with DA was less than that without DA at almost all observation stations. More detailed results will be presented in the conference.</p><p><strong>Acknowledgments</strong></p><p>This work was supported by the Korea Polar Research Institute (KOPRI, PN20081) and the Korea Meteorological Administration Research and Development Program under grant KMI2018-03712. The simulations are mostly carried out by utilising the supercomputer system supported by the National Center for Meteorological Supercomputer of Korea Meteorological Administration (KMA).</p>