The study was aimed to investigate the correlation between tidal effects and fog occurrence in Incheon and Mokpo, which are located in the middle and southern coasts of the West Sea of Korea, respectively. The investigation used meteorological data obtained from the automated synoptic observing systems and automatic weather stations and ocean data from tide stations from 2010 to 2019. Fog occurrence frequency was highest at high tide (Incheon, 41%; Mokpo, 45%). During fog event days at high tide, the dew-point depression was low (Incheon, 0.5 ℃; Mokpo, 0.4 ℃) and the relative humidity was high (Incheon, 97%; Mokpo, 9 8%). The w ind speed w as 2 . 4 m/s in I ncheon a nd 2 .0 m/s in M okpo, a nd t he m ain wind d irections w ere west-southwesterly from Incheon and southwesterly from Mokpo. In the fog case study, tidal flats were covered with water before and after the fog started. During the fog period, both stations experienced negative air-sea temperature differences, low dew-point depression, and high relative humidity were maintained, with weak winds forming from the tidal flats to the shore.

In this study, the impacts of local meteorology caused by tidal changes in the West Sea on ozone distributions in the Seoul Metropolitan Area (SMA) were analyzed using a meteorological model (WRF) and an air quality (CMAQ) model. This study was carried out during the day (1200–1800 LST) between August 3 and 9, 2016. The total area of tidal flats along with the tidal changes was calculated to be approximately 912 km2, based on data provided by the Environmental Geographic Information Service (EGIS) and the Ministry of Oceans and Fisheries (MOF). Modeling was carried out based on three experiments, and the land cover of the tidal flats for each experiment was designed using the coastal wetlands, water bodies (i.e., high tide), and the barren or sparsely vegetated areas (i.e., low tide). The land cover parameters of the coastal wetlands used in this study were improved in the herbaceous wetland of the WRF using updated albedo, roughness length, and soil heat capacity. The results showed that the land cover variation during high tide caused a decrease in temperature (maximum 4.5℃) and planetary boundary layer (PBL) height (maximum 1200 m), and an increase in humidity (maximum 25%) and wind speed (maximum 1.5 ms-1). These meteorological changes increased the ozone concentration (about 5.0 ppb) in the coastal areas including the tidal flats. The increase in the ozone concentration during high tide may be caused by a weak diffusion to the upper layer due to a decrease in the PBL height. The changes in the meteorological variables and ozone concentration during low tide were lesser than those occurring during high tide. This study suggests that the meteorological variations caused by tidal changes have a meaningful effect on the ozone concentration in the SMA.

Meteorological factors and air pollutants are associated with respiratory diseases, and appropriate use of weather and air quality information is helpful in the management of patients with such diseases. This study was performed to investigate both the utilization of weather and air quality information by, and the needs of, patients with respiratory diseases. Questionnaires were administered to 112 patients with respiratory diseases, 60.7% of whom were female. The rates of bronchial asthma and chronic obstructive pulmonary disease among patients were 67.0% and 10.7%, respectively. The majority of subjects (90%) responded that prevention was important for respiratory disease management and indicated that they used weather and air quality information either every day or occasionally. However, respondents underestimated the importance of weather and air quality information for disease management and were unaware of some types of weather information. The subjects agreed that respiratory diseases were sensitive to weather and air quality. The most important weather-related factors were diurnal temperature range, minimum temperature, relative humidity, and wind, while those for air quality were particulate matter and Asian dust. Information was gleaned mainly from television programs in patients aged 60 years and older and from smartphone applications for those below 60 years of age. The subjects desired additional information on the management and prevention of respiratory diseases. This study identified problems regarding the utility of weather and air quality information currently available for patients with respiratory diseases, who indicated that they desired disease-related information, including information in the form of action plans, rather than simple health- and air quality-related information. This study highlights the necessity for notification services that can be used to easily obtain information, specifically regarding disease management.

Provider-oriented weather information has been rapidly changing to become more customer-oriented and personalized. Given the increasing interest in wellness and health topics, the demand for health weather information, and biometeorology, also increased. However, research on changes in the human body according to weather conditions is still insufficient due to various constraints, and interdisciplinary research is also lacking. As part of an effort to change that, this study surveyed medical practitioners at an actual treatment site, using questionnaires, to investigate what kind of weather information they could utilize. Although there was a limit to the empirical awareness that medical staff had about weather information, most respondents noted that there is a correlation between disease and weather, with cardiovascular diseases (coronary artery disease (98.5%) and hypertension (95.9% ), skin diseases (atopic dermatitis (100%), sunburn (93.8%)) being the most common weather-sensitive ailments. Although there are subject-specific differences, most weather-sensitive diseases tend to be affected by temperature and humidity in general. Respiratory and skin diseases are affected by wind and solar radiation, respectively.

The effect of weather on disease was investigated based on results reported in academic papers. Weather-sensitive disease was selected by analyzing the frequency distributions of diseases and correlations between diseases and meteorological factors (e.g., temperature, humidity, pressure, and wind speed). Correlations between disease and meteorological factors were most frequently reported for myocardial infarction (MI) (28%) followed by chronic ischemic heart disease (CHR) (12%), stroke (STR) (10%), and angina pectoris (ANG) (5%). These four diseases had significant correlations with temperature (meaningful correlation for MI and negative correlations for CHR, STR, and ANG). Selecting MI, as a representative weather-sensitive disease, and summarizing the quantitative correlations with meteorological factors revealed that, daily hospital admissions for MI increased approximately 1.7%-2.2% with each 1℃ decrease in physiologically equivalent temperature. On the days when MI occurred in three or more patients larger daily temperature ranges (2.3℃ increase) were reported compared with the days when MI occurred in fewer than three patients. In addition, variations in pressure (10 mbar, 1016 mbar standard) and relative humidity (10%) contributed to an 11%-12% increase in deaths from MI and an approximately 10% increase in the incidence of MI, respectively.

In order to improve the prediction of the regional air quality modeling in the Seoul metropolitan area, a sensitivity analysis using two PBL and microphysics (MP) options of the WRF model was performed during four seasons. The results from four sets of the simulation experiments (EXPs) showed that meteorological variables (especially wind field) were highly sensitive to the choice of PBL options (YSU or MYJ) and no significant differences were found depending on MP options (WDM6 or Morrison) regardless of specific time periods, i.e. day and night, during four seasons. Consequently, the EXPs being composed of YSU PBL option were identified to produce better results for meteorological elements (especially wind field) regardless of seasons. On the other hand, the accuracy of all simulations for summer and winter was somewhat lower than those for spring and autumn and the effect according to physics options was highly volatile by geographical characteristics of the observation site.

The characteristics of atmospheric dispersion of radioactive material (i.e. 137Cs) related to local wind patterns around the Kori nuclear power plant (KNPP) were studied using WRF/HYSPLIT model. The cluster analysis using observed winds from 28 weather stations during a year (2012) was performed in order to obtain representative local wind patterns. The cluster analysis identified eight local wind patterns (P1, P2, P3, P4-1, P4-2, P4-3, P4-4, P4-5) over the KNPP region. P1, P2 and P3 accounted for 14.5%, 27.0% and 14.5%, respectively. Both P1 and P2 are related to westerly/northwesterly synoptic flows in winter and P3 includes the Changma or typhoons days. The simulations of P1, P2 and P3 with high wind velocities and constant wind directions show that 137Cs emitted from the KNPP during 0900~1400 LST (Local Standard Time) are dispersed to the east sea, southeast sea and southwestern inland, respectively. On the other hands, 5 sub-category of P4 have various local wind distributions under weak synoptic forcing and accounted for less than 10% of all. While the simulated 137Cs for P4-2 is dispersed to southwest inland due to northeasterly flows, 137Cs dispersed northward for the other patterns. The simulated average 137Cs concentrations of each local wind pattern are 564.1~1076.3 Bqm-3. The highest average concentration appeared P4-4 due to dispersion in a narrow zone and weak wind environment. On the other hands, the lowest average concentration appeared P1 and P2 due to rapid dispersion to the sea. The simulated 137Cs concentrations and dispersion locations of each local wind pattern are different according to the local wind conditions.