• 한국물환경학회지
• /
• 제36권5호
• /
• pp.392-404
• /
• 2020

The focus of this study was to quantify the thermal stratification and analyze the relationship between the stratification structure and the tributaries to understand flow variations in the Paldang Reservoir. The vertical distribution of the temperature and density gradients, and the depth and thickness of the thermocline were quantitatively calculated using a lake physics tool (rLakeAnalyzer) and high-frequency monitoring data. Based on a density gradient of 0.2 kg/㎥/m, the thermocline was formed from mid-May to early-September 2019 and the other periods were weakly stratified or mixed. The thickness of the thermocline was developed until 4.7 m and the depth of the thermocline was formed at a depth of 3 - 6 m at the front of the Paldang Reservoir. During the formation of the thermocline, the Namhangang and Gyeongancheon tributaries with relatively high water temperature (low-density) flowed into the upper layer of the reservoir, and the Bukhangang tributary with low water temperature (high-density) mainly affected the lower layer of the reservoir. This is because the density currents were formed due to the difference in the water temperature of the tributaries. The findings of this study may be used for constructing high-frequency monitoring and quantitative data analyses of reservoirs.

• Journal of Preventive Medicine and Public Health
• /
• 제30권1호
• /
• pp.31-43
• /
• 1997

Obesity usually is defined as the presence of and abnormally amount of adipose tissue. In many epidemiologic study, obesity as a health risk factor has been estimated by Body Mass Index(BMI) in general. This study was conducted to review of body fat percent measured by Bioelectric impedance analyzer as a estimator of obesity in a rural adult population. The study subjects were 421 men and 664 women who reside in the area on the Juam lake. They were sampled by multistage cluster sampling. Their mean age was 59 years old. Body fat percent increased with age, but BMI decreased with age in this study. Body fat percent was more larger at female and elder on the same BMI. The correlation coefficient between with body fat percent and body mass index was low (r=0.4737). Body fat percent was explained by not only BMI but also sex and age $(r^2=0.63)$. The result suggested that it is inadequate for BMI only to estimate obesity about elderly person who reside in the rural community. The relation of body fat percent and body mass index of this study agreed with the preceding know-ledges and studies in general.