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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Korean Meteorological Society
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Volume & Issues
Volume 22, Issue 4 - Dec 2012
Volume 22, Issue 3 - Sep 2012
Volume 22, Issue 2 - Jun 2012
Volume 22, Issue 1 - Mar 2012
Selecting the target year
Optimization of Mesoscale Atmospheric Motion Vector Algorithm Using Geostationary Meteorological Satellite Data
Kim, Somyoung ; Park, Jeong-Hyun ; Ou, Mi-Lim ; Cho, Heeje ; Sohn, Eun-Ha ;
Atmosphere, volume 22, issue 1, 2012, Pages 1~12
DOI : 10.14191/Atmos.2012.22.1.001
The Atmospheric motion vectors (AMVs) derived using infrared (IR) channel imagery of geostationary satellites have been utilized widely for real-time weather analysis and data assimilation into global numerical prediction model. As the horizontal resolution of sensors on-board satellites gets higher, it becomes possible to identify atmospheric motions induced by convective clouds (
scales). The National Institute of Meteorological Research (NIMR) developed the high resolution visible (HRV) AMV algorithm to detect mesoscale atmospheric motions including ageostrophic flows. To retrieve atmospheric motions smaller than
scale effectively, the target size is reduced and the visible channel imagery of geostationary satellite with 1 km resolution is used. For the accurate AMVs, optimal conditions are decided by investigating sensitivity of algorithm to target selection and correction method of height assignment. The results show that the optimal conditions are target size of 32 km
32 km, the grid interval as same as target size, and the optimal target selection method. The HRV AMVs derived with these conditions depict more effectively tropical cyclone OMAIS than IR AMVs and the mean speed of HRV AMVs in OMAIS is slightly faster than that of IR AMVs. Optimized mesoscale AMVs are derived for 6 months (Feb. 2010-Jun. 2010) and validated with radiosonde observations, which indicates NIMR's HRV AMV algorithm can retrieve successfully mesoscale atmospheric motions.
Study of Methodology for Estimating PM
Concentration of Asian Dust Using Visibility Data
Lee, Hyo-Jung ; Lee, Eun-Hee ; Lee, Sang-Sam ; Kim, Seungbum ;
Atmosphere, volume 22, issue 1, 2012, Pages 13~28
DOI : 10.14191/Atmos.2012.22.1.013
concentration data is useful for indentifying intensity and a transport way of Asian dust. However, it is difficult to identify them properly due to the limited spatial resolution and coverage. Therefore, a methodology to estimate
concentration using visibility data obtained from synoptic observation was developed. To derive the converting function, correlation between visibility and
concentration is investigated using visibility and
concentration data observed at 20 stations in Korea from 2005 to 2009. To minimize bias due to atmospheric moisture, data with higher relative humidity over a critical value were eliminated while deriving
-visibility relationship. As a result, an exponentially decreasing function of visibility is obtained under the condition that relative humidity is less than 82%. Verification of the visibility converting function to
concentration was carried out for the dust cases in 2010. It was found that spatial distributions of
calculated by visibility are in good agreement with the observed
distribution, especially for the strong dust cases in 2010. And correlation between the derived and observed
concentration was 0.63. We applied the function to obtain distributions of
concentration over North Korea, in which concentration data are not available, and compared them with satellite derived dust index, IODI distributions for dust cases in 2010. It is shown that the visibility function estimates quite similar patterns of dust concentration with IODI image, which suggests that it can contribute for prediction by indentifying transport route of Asian dust.
MTSAT Satellite Image Features on the Sever Storm Events in Yeongdong Region
Kim, In-Hye ; Kwon, Tae-Yong ; Kim, Deok-Rae ;
Atmosphere, volume 22, issue 1, 2012, Pages 29~45
DOI : 10.14191/Atmos.2012.22.1.029
An unusual autumn storm developed rapidly in the western part of the East sea on the early morning of 23 October 2006. This storm produced a record-breaking heavy rain and strong wind in the northern and middle part of the Yeong-dong region; 24-h rainfall of 304 mm over Gangneung and wind speed exceeding 63.7 m
over Sokcho. In this study, MTSAT-1R (Multi-fuctional Transport Satellite) water vapor and infrared channel imagery are examined to find out some features which are dynamically associated with the development of the storm. These features may be the precursor signals of the rapidly developing storm and can be employed for very short range forecast and nowcasting of severe storm. The satellite features are summarized: 1) MTSAT-1R Water Vapor imagery exhibited that distinct dark region develops over the Yellow sea at about 12 hours before the occurrence of maximum rainfall about 1100 KST on 23 October 2006. After then, it changes gradually into dry intrusion. This dark region in the water vapor image is closely related with the positive anomaly in 500 hPa Potential Vorticity field. 2) In the Infrared imagery, low stratus (brightness temperature:
) develops from near Bo-Hai bay and Shanfung peninsula and then dissipates partially on the western coast of Korean peninsula. These features are found at 10~12 hours before the maximum rainfall occurrence, which are associated with the cold and warm advection in the lower troposphere. 3) The IR imagery reveals that two convective cloud cells (brightness temperature below
) merge each other and after merging it grows up rapidly over the western part of East sea at about 5 hours before the maximum rainfall occurrence. These features remind that there must be the upward flow in the upper troposphere and the low-layer convergence over the same region of East sea. The time of maximum growth of the convective cloud agrees well with the time of the maximum rainfall.
Study on Dispersion Characteristics for Fire Scenarios in an Urban Area Using a CFD-WRF Coupled Model
Choi, Hee-Wook ; Kim, Do-Yong ; Kim, Jae-Jin ; Kim, Ki-Young ; Woo, Jung-Hun ;
Atmosphere, volume 22, issue 1, 2012, Pages 47~55
DOI : 10.14191/Atmos.2012.22.1.047
The characteristics of flow and pollutant dispersion for fire scenarios in an urban area are numerically investigated. A computational fluid dynamics (CFD) model coupled to a mesoscale weather research and forecasting (WRF) model is used in this study. In order to more accurately represent the effect of topography and buildings, the geographic information system (GIS) data is used as an input data of the CFD model. Considering prevailing wind, firing time, and firing points, four fire scenarios are setup in April 2008 when fire events occurred most frequently in recent five years. It is shown that the building configuration mainly determines wind speed and direction in the urban area. The pollutant dispersion patterns are different for each fire scenario, because of the influence of the detailed flow. The pollutant concentration is high in the horse-shoe vortex and recirculation zones (caused by buildings) close to the fire point. It thus means that the potential damage areas are different for each fire scenario due to the different flow and dispersion patterns. These results suggest that the accurate understanding of the urban flow is important to assess the effect of the pollutant dispersion caused by fire in an urban area. The present study also demonstrates that CFD model can be useful for the assessment of urban environment.
Orographic and Ocean Effects Associated with a Heavy Snowfall Event over Yeongdong Region
Cho, Kuh-Hee ; Kwon, Tae-Young ;
Atmosphere, volume 22, issue 1, 2012, Pages 57~71
DOI : 10.14191/Atmos.2012.22.1.057
Influences of orographic and ocean effect, which depend on the detailed geographic characteristics, upon winter time (December-February) precipitation in the Yeongdong region are investigated. Most of precipitation events in the Yeongdong region during the wintertime are associated with moist northeasterly (coming from the northeast direction) winds and also the spatial distribution of precipitation shows a great difference between Mountain area (Daegwallyeong) and Coastal area (Gangneung). The linear correlation coefficient between the meteorological variables obtained from NCEP/NCAR Reanalysis Data and precipitation amount for each precipitation type is calculated. Mountain type precipitation is dominated by northeasterly wind speed of the low level (1000 hPa and 925 hPa) and characterized with more precipitation in mountain area than coastal area. However, Coastal type precipitation is affected by temperature difference between ocean and atmosphere, and characterized with more precipitation in coastal area than mountain area. The results are summarized as follows; In the case of mountain type precipitation, the correlation coefficient between wind speed at 1000 hPa (925 hPa) and precipitation amount at Daegwallyeong is 0.60 (0.61). The correlation is statistical significant at 1% level. In the case of coastal type precipitation, the correlation coefficient of temperature difference between ocean and 925 hPa (850 hPa) over the East sea area and precipitation amount at Gangneung is 0.33 (0.34). As for the mountain type precipitation, a detailed analysis was conducted in order to verify the relationship between precipitation amount at Daegwallyeong and low level wind speed data from wind profiler in Gangneung and Buoy in the East Sea. The results also show the similar behavior. This result indicates that mountain type precipitation in the Yeongdong region is closely related with easterly wind speed. Thus, the statistical analysis of the few selected meteorological variables can be a good indicator to estimate the precipitation totals in the Yeongdong region in winter time.
Implementation of Improved Ice Particle Collision Efficiency in Takahashi Cloud Model
Lee, Hannah ; Yum, Seong Soo ;
Atmosphere, volume 22, issue 1, 2012, Pages 73~85
DOI : 10.14191/Atmos.2012.22.1.073
The collision efficiency data for collision between graupel or hail particles and cloud drops that take into account the differences of particle density are applied to the Takahashi cloud model. The original setting assumes that graupel or hail collision efficiency is the same as that of the cloud drops of the same volume. The Takahashi cloud model is run with the new collision efficiency data and the results are compared with those with the original. As an initial condition, a thermodynamic profile that can initiate strong convection is provided. Three different CCN concentration values and therefore three initial cloud drop spectra are prescribed that represent maritime (CCN concentration = 300
), continental (1000
) and extreme continental (5000
) air masses to examine the aerosol effects on cloud and precipitation development. Increase of CCN concentration causes cloud drop sizes to decrease and cloud drop concentrations to increase. However, the concentration of ice particles decreases with the increase of CCN concentration because small drops are difficult to freeze. These general trends are well captured by both model runs (one with the new collision efficiency data and the other with the original) but there are significant differences: with the new data, the development of cloud and raindrop formation are delayed by (1) decrease of ice collision efficiency, (2) decrease of latent heat from riming process and (3) decrease of ice crystals generated by ice multiplication. These results indicate that the model run with the original collision efficiency data overestimates precipitation rates.
On the Contrast of Aerosol Size Distribution and Cloud Condensation Nuclei Concentrations between the East and the West of the Korean Peninsula
Kim, Jong Hwan ; Park, Min-Su ; Shim, Sungbo ; Yum, Seong Soo ;
Atmosphere, volume 22, issue 1, 2012, Pages 87~96
DOI : 10.14191/Atmos.2012.22.1.087
Aerosol number concentration (
), size distribution and cloud condensation nuclei (CCN) concentration (
) were measured during 16-21 August 2008 at Daegwallyeong (DG) located in the eastern rural region of the Korean Peninsula. In the very next week (22-29 August 2008) the same aerosol properties were measured at Yeongjong Island (YJ) in the Yellow Sea.
for all 3 size cuts (above 3, 6 and 10 nm) was significantly higher at DG than YJ, but
was significantly lower at the former and resulted in the
ratio more than twice higher at YJ (
at 0.53% supersaturation). The geometric mean diameter at DG,
, was much smaller than that at YJ,
, due to the particle formation events that were likely to have occurred continuously at DG. For given mean diameter, aerosols were more likely to act as CCN at YG compared to those at DG.
The Variation of Aerosol Number Concentrations in Relation with 3D Wind Components in the Ieodo Ocean Research Station
Park, Sung-Hwa ; Jang, Sang-Min ; Lee, Dong-In ; Jung, Woon-Seon ; Jeong, Jong-Hoon ; Jung, Sung-A ; Jung, Chang Hoon ; Kim, Kyungsik ; Kim, Kyung-Eak ;
Atmosphere, volume 22, issue 1, 2012, Pages 97~107
DOI : 10.14191/Atmos.2012.22.1.097
To investigate variation of aerosol number concentration at each different size with three-dimensional (3D) wind components in ocean area, aerosol particles and 3D wind components were measured in the Ieodo Ocean Research Station, which is located to 419 km southwest from Marado, the southernmost island of Korea, from 25 June to 8 July 2010. The Laser Particle Counter (LPC) and ultrasonic anemometer were used to measure the size of aerosol particles and 3D wind components (zonal (u), meridional (v), and vertical (w) wind) respectively. Surface weather chart, NCEP/NCAR reanalysis data and sounding data were used to analyze the synoptic condition. The distribution of aerosol number concentration had a large variation from bigger particles more than 1.0
in diameter by wind direction during precipitation. In the number concentration of aerosol particles with respect to the weather conditions, particles larger than 1.0
in size were decreased and sustained to the similar concentration at smaller particles during precipitation. The increase in aerosol number concentration was due to the sea-salt particles which was suspended by southwesterly and upward winds. In addition, the aerosol number concentration with vertical wind flow could be related with the occurrence and increasing mechanism of aerosol in marine boundary layer.
Hybrid Parallelization for High Performance of CFD_NIMR Model
Kim, Min-Wook ; Choi, Young-Jean ; Kim, Young-Tae ;
Atmosphere, volume 22, issue 1, 2012, Pages 109~115
DOI : 10.14191/Atmos.2012.22.1.109
We parallelized the CFD_NIMR model, which is a numerical meteorological model, for best performance on both of distributed and shared memory parallel computers. This hybrid parallelization uses MPI (Message Passing Interface) to apply horizontal 2-dimensional sub-domain out of the 3-dimensional computing domain for distributed memory system, as well as uses OpenMP (Open Multi-Processing) to apply vertical 1-dimensional sub-domain for utilizing advantage of shared memory structure. We validated the parallel model with the original sequential model, and the parallel CFD_NIMR model shows efficient speedup on the distributed and shared memory system.
Impact of Snow Depth Initialization on Seasonal Prediction of Surface Air Temperature over East Asia for Winter Season
Woo, Sung-Ho ; Jeong, Jee-Hoon ; Kim, Baek-Min ; Kim, Seong-Joong ;
Atmosphere, volume 22, issue 1, 2012, Pages 117~128
DOI : 10.14191/Atmos.2012.22.1.117
Does snow depth initialization have a quantitative impact on sub-seasonal to seasonal prediction skill? To answer this question, a snow depth initialization technique for seasonal forecast system has been implemented and the impact of the initialization on the seasonal forecast of surface air temperature during the wintertime is examined. Since the snow depth observation can not be directly used in the model simulation due to the large systematic bias and much smaller model variability, an anomaly rescaling method to the snow depth initialization is applied. Snow depth in the model is initialized by adding a rescaled snow depth observation anomaly to the model snow depth climatology. A suite of seasonal forecast is performed for each year in recent 12 years (1999-2010) with and without the snow depth initialization to evaluate the performance of the developed technique. The results show that the seasonal forecast of surface air temperature over East Asian region sensitively depends on the initial snow depth anomaly over the region. However, the sensitivity shows large differences for different timing of the initialization and forecast lead time. Especially, the snow depth anomaly initialized in the late winter (Mar. 1) is the most effective in modulating the surface air temperature anomaly after one month. The real predictability gained by the snow depth initialization is also examined from the comparison with observation. The gain of the real predictability is generally small except for the forecasting experiment in the early winter (Nov. 1), which shows some skillful forecasts. Implications of these results and future directions for further development are discussed.
Restoration of 19th-century Chugugi Rainfall Data for Wonju, Hamheung and Haeju, Korea
Kim, Sang-Won ; Park, Jun-Sang ; Kim, Jin-A ; Hong, Yoon ;
Atmosphere, volume 22, issue 1, 2012, Pages 129~135
DOI : 10.14191/Atmos.2012.22.1.129
This study restores rainfall measurements taken with the Chugugi (rain gauge) at Wonju, Hamheung, and Haeju from the Deungnok (government records from the Joseon Dynasty). We restored rainfall data corresponding to a total of 9, 13, and 18 years for Wonju, Hamheung, and Haeju, respectively. Based on the restored data, we reconstructed monthly rainfall data. Restoration was most successful for the rainy season months of June, July and August. The restored rainfall data were compared with the summer rainfall data for Seoul as recorded by the Seungjeongwon (Royal Secretariat). In June, the variation in the restored rainfall data was similar to that of the Seungjeongwon data for Seoul. In July and August, however, the variations in the reconstructed data were markedly different from those in the Seoul data (Seungjeongwon). In the case of the worst drought in the summer of 1888, a substantial shortage of rainfall was found in both the Seungjeongwon data for Seoul and the restored data for the three regional locations.