Time filter

Source Type

Lee Y.-H.,Kyungpook National University | Ahn K.-D.,National Institute of Meteorological science | Lee Y.H.,National Institute of Meteorological science
Boundary-Layer Meteorology | Year: 2016

We have developed a parametrization of tidal effects for use in the Noah land-surface model and have validated the land-surface model using observations taken over a tidal flat of the western coast of South Korea. The parametrization is based on the energy budget of a water layer with varying thickness above the soil. During flood tide, heat transfer by the moving water is considered in addition to the surface energy budget. In addition, partial penetration of solar radiation through the water layer is considered in the surface energy budget, and the water thickness varying with time is used as an additional input. Seven days with clear-sky conditions and westerly winds during the daytime are selected for validation of the model. Two simulations are performed in an offline mode: a control simulation without the tidal effect (CONTROL) and a simulation with the tidal effect (TIDE). Comparisons of results have been made with eddy-covariance measurements and soil temperature data for the tidal flats. Observations show that inundation significantly reduces both sensible and latent heat fluxes during daytime, which is well simulated in the TIDE simulation. The diurnal variation and magnitude of soil temperature are better simulated in the TIDE than in the CONTROL simulation. Some underestimation of the latent heat flux over the water surface is partly attributed to the use of one layer of water and the underestimated roughness length at this site. In addition, other model deficiencies are discussed. © 2016 Springer Science+Business Media Dordrecht


Ahn M.-H.,Ewha Womans University | Won H.Y.,Ewha Womans University | Han D.,Ewha Womans University | Kim Y.-H.,National Institute of Meteorological science | Ha J.-C.,National Institute of Meteorological science
Atmospheric Measurement Techniques | Year: 2016

The ground-based microwave sounding radiometers installed at nine weather stations of Korea Meteorological Administration alongside with the wind profilers have been operating for more than 4 years. Here we apply a process to assess the characteristics of the observation data by comparing the measured brightness temperature (Tb) with reference data. For the current study, the reference data are prepared by the radiative transfer simulation with the temperature and humidity profiles from the numerical weather prediction model instead of the conventional radiosonde data. Based on the 3 years of data, from 2010 to 2012, we were able to characterize the effects of the absolute calibration on the quality of the measured Tb. We also showed that when clouds are present the comparison with the model has a high variability due to presence of cloud liquid water therefore making cloudy data not suitable for assessment of the radiometer's performance. Finally we showed that differences between modeled and measured brightness temperatures are unlikely due to a shift in the selection of the center frequency but more likely due to spectroscopy issues in the wings of the 60 GHz absorption band. With a proper consideration of data affected by these two effects, it is shown that there is an excellent agreement between the measured and simulated Tb. The regression coefficients are better than 0.97 along with the bias value of better than 1.0 K except for the 52.28 GHz channel which shows a rather large bias and variability of-2.6 and 1.8 K, respectively. © 2016 Author(s).


Hussain M.S.,Konkuk University | Kim S.,National Institute of Meteorological science | Lee S.,Konkuk University
Theoretical and Applied Climatology | Year: 2016

This study investigated the relationship between the Indian Ocean Dipole (IOD) and the precipitation of Pakistan using data for the period of 1958–2010. The long-term evolution of the IOD index did not show interannual patterns similar to those of the annual precipitation of Pakistan. No linkage between the co-occurring trends of the IOD and the precipitation was traced during the period of investigation. The correlation between the IOD and the precipitation of Pakistan indicated a noteworthy impact over the monsoonal regions, especially the coastal area and the western region of Pakistan, which showed a significant positive correlation between the IOD index and annual and summer precipitation. A significant positive relationship was also revealed between the precipitation of the Balochistan Plateau and the IOD index for the summer monsoon season. No connection was observed between the IOD and the precipitation of the northern regions and the upper Indus Plain of Pakistan. Positive phases of the IOD have been noted to occur along with surplus precipitation during active monsoon conditions. The southeasterly wind moves from the Arabian Sea and transports additional moisture from the Arabian Sea to the coastal and southwestern parts of Pakistan during positive phases of the IOD. © 2016 Springer-Verlag Wien


PubMed | Hanyang University and National Institute of Meteorological science
Type: Journal Article | Journal: International journal of biometeorology | Year: 2016

Pollen is an important cause of respiratory allergic reactions. As individual sanitation has improved, allergy risk has increased, and this trend is expected to continue due to climate change. Atmospheric pollen concentration is highly influenced by weather conditions. Regression analysis and modeling of the relationships between airborne pollen concentrations and weather conditions were performed to analyze and forecast pollen conditions. Traditionally, daily pollen concentration has been estimated using regression models that describe the relationships between observed pollen concentrations and weather conditions. These models were able to forecast daily concentrations at the sites of observation, but lacked broader spatial applicability beyond those sites. To overcome this limitation, an integrated modeling scheme was developed that is designed to represent the underlying processes of pollen production and distribution. A maximum potential for airborne pollen is first determined using the Weibull probability density function. Then, daily pollen concentration is estimated using multiple regression models. Daily risk grade levels are determined based on the risk criteria used in Korea. The mean percentages of agreement between the observed and estimated levels were 81.4-88.2% and 92.5-98.5% for oak and Japanese hop pollens, respectively. The new models estimated daily pollen risk more accurately than the original statistical models because of the newly integrated biological response curves. Although they overestimated seasonal mean concentration, they did not simulate all of the peak concentrations. This issue would be resolved by adding more variables that affect the prevalence and internal maturity of pollens.


Kim J.-A.,National Institute of Meteorological science | Byun H.-R.,Pukyong National University
Meteorology and Atmospheric Physics | Year: 2016

The spatiotemporal distributions of latest frost dates (LFDs) on the Korean Peninsula and the atmospheric circulation patterns that resulted in the latest frosts (LFs) were investigated through the use of historical records and modern weather observation data. During the modern observation period since 1904, the most recent record of LF was April 28, 2013 at Daegwallyeong. On average, the LF occurred in Korea between March 17 (at Wando) and May 10 (at Daegwallyeong). Positive correlations were found between LFD and altitude and latitude. Additionally, inter- annual variation of LFD showed a trend of progressively earlier dates at 32 of the 48 stations at which data were available. The historic data set consists of the following: 39 records of frosts during the Three-States Period (57 BC–998 AD): 34 records during the Goryeo Dynasty (998–1391), among which the latest record was in July of the lunar calendar: and 498 during the Joseon Dynasty (1392–1928) with one LF dated August 31, 1417 on the solar calendar. Regarding LFD from The Annals of the Joseon Dynasty, April has 11 records, May has 55, June has 46, July has 21, and August has 5 LFD records. Various meteorological causes of the latest LF were then established. Firstly, a cold and humid north-easterly current that originates from high latitudes of more than 50°N and passes through the East Sea is considered one of the dominant causes of LF. Secondly, strong radiative cooling under clear skies is suspected as another important cause. Thirdly, a specific pressure pattern, called the ‘inverted-S contour’ or ‘North High and South Low (NHSL) pattern’ was found to be a favorable condition for LF. Finally the latest LF was not found to be related to monthly or longer-term cold climate, but are instead linked to the abrupt development of a strong ridge over inland Asia and the unusual southward movement of the tall polar cyclone over the North Pacific Ocean. © 2016 Springer-Verlag Wien


Choi J.-W.,National Institute of Meteorological science | Cha Y.,National Typhoon Center
Dynamics of Atmospheres and Oceans | Year: 2016

This study has developed the index for diagnosis on possibility that tropical cyclones (TCs) affect Korean Peninsula. This index is closely related to the strength of the western North Pacific subtropical high (WNPSH), which is calculated as a difference in meridional wind between at the highest correlation area (around Korean Peninsula) and at the lowest correlation area (sea southeast of Japan) through a correlation analysis between TC frequency that affects Korean Peninsula and 500 hPa meridional wind. In low frequency years that selected from Korea affecting TC index, anomalous northeasterly is strengthened from Korea to the South China Sea because the center of anomalous anticyclonic circulation is located to northwest of Korean Peninsula. Thus, TCs tend to move westward from the sea east of the Philippines to the mainland China. On the other hand, in high frequency years, anomalous southwesterly serves as steering flow that more TCs move toward Korean Peninsula because the center of anomalous anticyclonic circulation is located to sea east of Japan. Consequently, this study suggests that if this index is calculated using real time 500 hPa meridional winds that forecasted by dynamic models during the movement of TCs, the possibility that TCs approach Korean Peninsula can be diagnosed in real time. © 2016 Elsevier B.V.


Jung E.,University of Miami | Jung E.,National Institute of Meteorological science | Albrecht B.A.,University of Miami | Sorooshian A.,University of Arizona | And 2 more authors.
Atmospheric Chemistry and Physics | Year: 2016

Precipitation tends to decrease as aerosol concentration increases in warm marine boundary layer clouds at fixed liquid water path (LWP). The quantitative nature of this relationship is captured using the precipitation susceptibility (So) metric. Previously published works disagree on the qualitative behavior of So in marine low clouds: So decreases monotonically with increasing LWP or cloud depth (H) in stratocumulus clouds (Sc), while it increases and then decreases in shallow cumulus clouds (Cu). This study uses airborne measurements from four field campaigns on Cu and Sc with similar instrument packages and flight maneuvers to examine if and why So behavior varies as a function of cloud type. The findings show that So increases with H and then decreases in both Sc and Cu. Possible reasons for why these results differ from those in previous studies of Sc are discussed. © Author(s) 2016.


Choi J.-W.,National Institute of Meteorological science | Kim I.-G.,National Institute of Meteorological science | Kim J.-Y.,National Institute of Meteorological science
Theoretical and Applied Climatology | Year: 2016

The statistical change-point analysis demonstrates that there is a climate regime shift in the April mean precipitation in Korea in 1981. The April mean precipitation in the years post-1981 showed a distinct decrease compared to the years pre-1981. This phenomenon was also noticed in China and Japan, excluding south China. One of the major causes for this decrease in April mean precipitation was the increased snow depth in the mid-latitude regions of continental East Asia. This resulted in a strengthened cold and dry anticyclone anomaly over continental East Asia and a relatively weakened subtropical anticyclone anomaly over the western North Pacific, thus forcing a continuation of the typical winter pressure pattern of “high-West and low-East” in East Asia in April. The strengthened northerly anomaly from this zonal pressure pattern anomaly played a significant role in restricting the northern movement of the subtropical anticyclone and preventing the inflow of warm and humid air into Korea. © 2016 Springer-Verlag Wien


The present invention relates to an apparatus for detecting photons according to an atmospheric condition, using a function of adjusting light quantity that can significantly improve reliability of an atmospheric condition analysis result by minimizing noise in a spectrum by maintaining the quantity of incident light uniform within a predetermined range regardless of atmospheric conditions and changes, and to a method of adjusting light quantity. The apparatus for detecting photons in accordance with atmospheric conditions using a function of adjusting light quantity includes: an apparatus case having a light inlet; a light quantity adjuster disposed under the light inlet and adjusting quantity of incident light such that a predetermined quantity of light travels inside; and a controller controlling operation of the light quantity adjuster in accordance with intensity of light detected by the light quantity adjuster.


The present invention relates to an apparatus for detecting photons according to an atmospheric condition, using a function of adjusting light quantity that can significantly improve reliability of an atmospheric condition analysis result by minimizing noise in a spectrum by maintaining the quantity of incident light uniform within a predetermined range regardless of atmospheric conditions and changes, and to a method of adjusting light quantity. The apparatus for detecting photons in accordance with atmospheric conditions using a function of adjusting light quantity includes: an apparatus case having a light inlet; a light quantity adjuster disposed under the light inlet and adjusting quantity of incident light such that a predetermined quantity of light travels inside; and a controller controlling operation of the light quantity adjuster in accordance with intensity of light detected by the light quantity adjuster.

Loading National Institute of Meteorological science collaborators
Loading National Institute of Meteorological science collaborators