• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.267-273
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• 2000

Temperature-associated emergence patterns for a hydropsychid caddisfly, Hydropsyche kozhantschikovi, were studied from the Wangsuk creek in Kyonggi-do from April to June in 1999. Emerging adults were quantitatively collected by pyramidshaped emergence traps. Water temperature was hourly monitored in 1999. The emergence began at April 15 when the daily mean water temperature rose to ca. $10^{\circ}C$: it rapidly increased and peaked in ca. 10 days, and continued to May 25, lasting 40 days since the starting date. The average number of emerged adults was $35.8\;inds./m^2$ and their sex ratio was male (M) : female (F) = 1 : 2.04. The emergence of males was ca. 2 days earlier than that of females. Daily, the emergence was a bigeminans pattern representing the major peak (66.7%) just after dark ($19:00{\sim}21:00$) and theminor peak (11.1%) just before dawn ($05:00{\sim}07:00$). According to our degree dayaccumulation (DD) model, it respectively required 453.89DD (M: 440.48DD and F: 473.97 DD), 615.71DD (M: 610.18DD and F: 622.09DD), and 820.24DD (M: 828.25DD and F: 804.71DD) to begin, to reach the peak, and to finish the emergence.

• Journal of fish pathology
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• v.8 no.2
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• pp.157-164
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• 1995

In order to examine the effects of $O_2$ saturation and pH on gas-bubble disease of blue crab, portunus trituberculatus, zoeal larvae were reared under 5 different concentrations (6.0, 4.0, 3.1, 2.2, and 0.7million cell/cc) of Chlamydomones sp. under natural light for 4days. Observed pH and $O_2$ saturation in the rearing chamber increased drastically from 12 to 18 o'clock with the increasing of Chlamydomones sp. concentrations, but rapidly decreased from 2 to 6 o'clock in the rearing chamber. Gas-bubble disease of zoeal larvae was observed 4hours after starting of experiment at the pH 8.5 and 118% $O_2$ saturated conditions in rearing chamber during the day, and recovered rapidly with the decreasing of pH and $O_2$ saturation at night. Thus, gas-bubble disease of zoeal larvae was repeated with the increased pH($\geq$8.5) and $O_2$ saturation ($\geq$118%) almost every days. Mortality of zoeal larvae was observed when pH and $O_2$ saturations were reached 8.5 and 118% levels respectively, and deteriorated with the increasing of water temperature, pH and $O_2$ saturation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.4
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• pp.321-333
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• 1997

This paper describe on the transmitting/receiving functions and the monitoring effects for the telemetry system which is designed to monitor the environmental condition of a culturing fishery ground inside a bay. The telemetry experiments were carried out by the telemetry system which constructed with the sea water temperature/salinity measuring sensor and telesounder at culturing fishery ground located in the coast of Sangyang-Myon, Kyongsangnam-Do province from October, 1995 to May, 1996. The results of this experiment showed that the developed telemetry system could be used for monitoring the sea water temperature/salinity and the distribution of fish in culturing fishery ground.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.221-228
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• 2019

The effects of wind speed on the temperature change during day time could be insignificant in a region with a complex terrain. The objective of this study was to derive empirical relationship between solar radiation and hourly temperature under a windy condition for the period from sunrise to sunset in order to improve hourly air temperature at a site-specific scale. The deviation of the temperature measurements was analyzed along with the changes of the hourly sunlight at weather observation sites located on the east and west slopes under given wind speed. An empirical model where wind speed use used as an independent variable was obtained to quantify the solar effects on the temperature change (MJ/㎡). This model was verified estimating the hourly temperature during the daytime (0600-1900 h) at 25 weather observation sites located in the study area that has complex topography for the period from January to December 2018. The mean error (ME) and root mean square error (RMSE)of the estimated and measured values ranged from -0.98 to 0.67 ℃, and from 0.95 to 2.04 ℃, respectively. The daytime temperature at 1500 h were estimated using new and previous models. It was found that to the model proposed in the present study reduced the measurement errors of the hourly temperature in the afternoon in comparison with the previous model. For example, the ME and RMSE of the previous model were (ME -0.91 ℃ and 1.47 ℃, respectively. In contrast, the values of ME and RMSE were -0.45 ℃ and 1.22 ℃ for the new model, respectively. Our results suggested that the reliability of hourly temperature estimates at a specific site could be improved taking into account the effect of wind as well as solar radiation.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.1-9
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• 2020

The purpose of this study is to verify the effects of ventilation corridor and derive adequate policy alternatives to its application for the city of Sejong, which is located in an inland of Korean Peninsula. In order to introduce the ventilation corridor in the city, it is necessary both to understand change on fresh air flow affected by the construction of new cities and to show its effects which are able to circulate air flow of the city. The study identified ventilation effects using computational fluid dynamics models. In particular, it analyzed change on wind speed and direction after constructing of a new town and cool air flow along the lowlands generated after sunset. In addition, it identified those of reducing particulate matter when arranging buildings conforming to the ventilation corridor at block level. The policy implications derived from simulation can be summarized as follows. First, it is desirable to plan ventilation corridors so that fresh air from mountains, forests, and valleys can flow into cities and mitigate the concentration of particulate matter. Furthermore, public facilities covering parks, plazas, and playgrounds should be installed preferentially to attract safe outdoor activities near to areas with low levels of particulate matter. Finally, it is adequate to prepare for a number of alternative plans by analyzing ventilation corridors when setting out district unit plan.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.21 no.1
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• pp.31-46
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• 1993

A radiative transfer model with two-stream/delta-Eddington approximation has been developed to calculate the vertical distributions of atmospheric heating rates and radiative fluxes. The performance of the model has been evaluated by comparison with the results of ICRCCM (Intercomparison of radiative codes in climate models). It has been demonstrated that the presented model has a capability to calculate the solar radiation not only accurately but also economically. The characteristics of ultraviolet-B radiation (UV-B; 280-320nm) are examined by comparison of relation between the flux at the top of atmosphere and that at the surface. The relation of UV-B is quadratic due to the strong ozone absorption in this band. Also, the dependence of the UV-B radiation on the stratospheric ozone depletion and stratospheric aerosol haze due to volcanic eruption on the stratospheric ozone depletion and stratospheric aerosol haze due to volcanic eruption has been tested with various solar zenith angles. The surface UV-B increases as the solar zenith angle increases. The existence of stratospheric aerosols causes an increase in the planetary albedo due to the aerosols' backscattering. The planetary albedo with aerosol's effect has been increases as the solar zenith angle is not sensitive. It may be caused by the fact that the aerosols' scattering effect becomes saturated with the relatively long path length in a large solar zenith angle. Finally, the regional impact of stratospheric aerosols due to volcanic eruption on the intensity of UV-B radiation at the surface has been estimated. A direct effect is that the flux is diminished at the low latitudes, while it is enhanced in the high latitudes by the aerosols' photon trap or twilight effect. In the high latitudes, both aerosols' scattering and ozone absorption have strong and opposite impacts to the surface UV-B radiation is located at the mid-latitudes during spring season in both hemispheres.

• The Korean Journal of Ecology
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• v.28 no.1
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• pp.45-53
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• 2005

Urban stream is an important place supporting urban ecosystem. This study was carried out to clarify the role of Jungrangchun for wintering waterbirds in Seoul. We monitored the fluctuation of waterbirds population using our census data (1997/98 winter) and pervious census data (the Ministry of Environment and National Institute of Environmental Research $1999{\sim}2004$). Wintering behaviours of common teals (Anas crecca) were also observed to understand the habitat use of waterbirds in this area. As a result of this, Jungrangchun was an important place to support $3,004\sim8,237$ wintering birds, mainly dabbling ducks and diving ducks. The population of diving ducks showed high annual fluctuation whilst the population of dabbling ducks regularly used this area every year The maximum number of waterbirds foraged and rested in late January and late February. In daily use, the number of waterbirds increased on afternoon and rapidly increased after sunset. It is assumed that waterbirds used this area not only as a nocturnal feeding site but also daytime feeding site. Thus, this result suggest that Jungrangchun is important for not only the daily use but also the nocturnal use of wintering waterbirds. The number of diving ducks was increased with low temperature and high wind speed. Therefore, this area was also a shelter of diving ducks on chilly and windy day.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.253-257
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• 2011

This study was carried out to investigate the effect of different light emitting diode (LED) irradiation on the growth of paprika (Capsicum annuum 'Cupra'). The plants were irradiated by red (660 nm), blue (460 nm) and red + blue (4 : 1) light emitting diodes above 50 cm for 5 hours after sunset. Photosynthetic photon flux (PPF) irradiated by red, blue and red + blue LED were $79{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $75{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and $102{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ respectively. Leaf temperature of paprika grown under blue LED irradiation was the highest of $18.6^{\circ}C$. Fruit temperature was the highest under in the control (no irradiation) but it was lower than leaf temperature. There was influence of LED irradiation on the paprika plants height; under blue irradiation the plant height was the shortest, while under in the control plant height was the highest. The leaf size of under different LED irradiation was bigger than that of in the control. Mean fruit weight under different LED irradiation was significantly increased; however number of fruits and marketable yield per plant were significantly decreased as compared to the control.

• Korean Journal of Ichthyology
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• v.19 no.3
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• pp.236-245
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• 2007

Feeding habits of Liobagrus andersoni were investigated in a tributary of the Namhan river from October 2005 to October 2006. L. andersoni was considered as an entirely bottom-feeding carnivore based on it's stomach contents. Because, the diet of L. andersoni was mainly aquatic insect such as Ephemeroptera, Trichoptera, Diptera. The most important prey was Ephemeroptera species. Small sized individuals (<50 mm SL) fed mainly on small prey organisms such as Baetis. However, larger Ephemeroptera and Trichoptera were heavily selected with increasing fish size. The relative proportion of food items was changed with season. The prey materials were more various at summer and autumn than winter. L. andersoni eaten Ephemeroptera intensively in spring and summer but eaten Trichoptera and Chironomidae in winter. Feeding activity of L. andersoni was started after sunset and was most active at midnight, but the activity was reduced after sunrise and during day period. So it was considered that L. andersoni was a nocturnal stalkers.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.204-208
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• 2000

Little information is available for the temporal variation in air temperature profile within rice canopies under development, while much works have been done for a fully developed canopy. Fine wire thermocouples of 0.003 mm diameter (chromel-constantan) were installed at 10 vertical heights by a 10 cm step in a paddy rice field to monitor the air temperatures over and within the developing rice canopy from one month after transplanting (June 29) to just before heading (August 24). According to a preliminary analysis of the data, we found neither the daytime temperature maximum nor the night time minimum at the active radiation surface (the canopy height with maximum leafages) during this period, which is a typical profile of a fully developed canopy. Air temperature within the canopy never exceeded that above the canopy at 1.5 m height during the daytime. Temporal march of the within-canopy profile seemed to be controlled mainly by the ambient temperature above the canopy and the water temperature beneath the canopy, and to some extent by the solar altitude, resulting in alternating isothermal and inversion structures.