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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Meteorological Society
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Volume & Issues
Volume 25, Issue 4 - Dec 2015
Volume 25, Issue 3 - Sep 2015
Volume 25, Issue 2 - Jun 2015
Volume 25, Issue 1 - Mar 2015
Selecting the target year
Representation of Model Uncertainty in the Short-Range Ensemble Prediction for Typhoon Rusa (2002)
Kim, Sena ; Lim, Gyu-Ho ;
Atmosphere, volume 25, issue 1, 2015, Pages 1~18
DOI : 10.14191/Atmos.2015.25.1.001
The most objective way to overcome the limitation of numerical weather prediction model is to represent the uncertainty of prediction by introducing probabilistic forecast. The uncertainty of the numerical weather prediction system developed due to the parameterization of unresolved scale motions and the energy losses from the sub-scale physical processes. In this study, we focused on the growth of model errors. We performed ensemble forecast to represent model uncertainty. By employing the multi-physics scheme (PHYS) and the stochastic kinetic energy backscatter scheme (SKEBS) in simulating typhoon Rusa (2002), we assessed the performance level of the two schemes. The both schemes produced better results than the control run did in the ensemble mean forecast of the track. The results using PHYS improved by 28% and those based on SKEBS did by 7%. Both of the ensemble mean errors of the both schemes increased rapidly at the forecast time 84 hrs. The both ensemble spreads increased gradually during integration. The results based on SKEBS represented model errors very well during the forecast time of 96 hrs. After the period, it produced an under-dispersive pattern. The simulation based on PHYS overestimated the ensemble mean error during integration and represented the real situation well at the forecast time of 120 hrs. The displacement speed of the typhoon based on PHYS was closest to the best track, especially after landfall. In the sensitivity tests of the model uncertainty of SKEBS, ensemble mean forecast was sensitive to the physics parameterization. By adjusting the forcing parameter of SKEBS, the default experiment improved in the ensemble spread, ensemble mean errors, and moving speed.
Preliminary Analysis of Data Quality and Cloud Statistics from Ka-Band Cloud Radar
Ye, Bo-Young ; Lee, GyuWon ; Kwon, Soohyun ; Lee, Ho-Woo ; Ha, Jong-Chul ; Kim, Yeon-Hee ;
Atmosphere, volume 25, issue 1, 2015, Pages 19~30
DOI : 10.14191/Atmos.2015.25.1.019
The Ka-band cloud radar (KCR) has been operated by the National Institute of Meteorological Research (NIMR) of Korea Meteorological Administration (KMA) at Boseong National Center for Intensive Observation of severe weather since 2013. Evaluation of data quality is an essential process to further analyze cloud information. In this study, we estimate the measurement error and the sampling uncertainty to evaluate data quality. By using vertically pointing data, the statistical uncertainty is obtained by calculating the standard deviation of each radar parameter. The statistical uncertainties decrease as functions of sampling number. The statistical uncertainties of horizontal and vertical reflectivities are identical (0.28 dB). On the other hand, the statistical uncertainties of Doppler velocity (spectrum width) are 2.2 times (1.6 times) larger at the vertical channel. The reflectivity calibration of KCR is also performed using X-band vertically pointing radar (VertiX) and 2-dimensional video disdrometer (2DVD). Since the monitoring of calibration values is useful to evaluate radar condition, the variation of calibration is monitored for five rain events. The average of calibration bias is 10.77 dBZ and standard deviation is 3.69 dB. Finally, the statistical characteristics of cloud properties have been investigated during two months in autumn using calibrated reflectivity. The percentage of clouds is about 26% and 16% on September to October. However, further analyses are required to derive general characteristics of autumn cloud in Korea.
Three Cases with the Multiple Occurrences of Freezing Rain in One Day in Korea (12 January 2006; 11 January 2008; and 22 February 2009)
Park, Chang-Kyun ; Byun, Hi-Ryong ;
Atmosphere, volume 25, issue 1, 2015, Pages 31~49
DOI : 10.14191/Atmos.2015.25.1.031
From the hourly data of 75 Korean weather stations over a 12-year period (2001~2012), this study has chosen three cases (January 12, 2006; January 11, 2008; and February 22, 2009) of multiple freezing rains and investigated the atmospheric circulations that seemed to cause the events. As a result, the receding high pressure type (2006), prevailing high pressure type (2008), and warm front type (2009) are confirmed as synoptic patterns. In all three cases, freezing rain was found in regions with a strong ascending current near the end point of a low-level jet that carried the warm humid air from low latitudes. The strong ascending current resulted from lower-level convergence and upper-level divergence. In 2006 and 2009, the melting process was confirmed. In 2008, the supercooled warm rain process (SWRP) was confirmed. In contrast to existing SWRP theory, it was found that the cool air produced at the middle atmosphere and near the earth's surface led to the formation of freezing rain. The sources of this cool air were supposed to be the evaporative latent heat and the cold advection coming from the northeast. On the other hand, a special case was detected, in which the freezing rain occurred when both the soil surface temperature and surface air temperature were above
. The thickness distributions related to freezing rain in Korea were found to be similar to those in North America. A P-type nomogram was considered for freezing rain forecasting; however, it was not relevant enough to Korea, and few modifications were needed.
WRF Sensitivity Experiments on the Formation of the Convergent Cloud Band in Relation to the Orographic Effect of the Korean Peninsula
Kim, Yu-Jin ; Lee, Jae Gyoo ;
Atmosphere, volume 25, issue 1, 2015, Pages 51~66
DOI : 10.14191/Atmos.2015.25.1.051
This study was conducted to perform various sensitivity experiments using WRF (Weather Research and Forecasting) model in order to determine the effects of terrains of the Korean Peninsula and the land-sea thermal contrast on the formation and development of the convergent cloud band for the cases of 1 February 2012. The sensitivity experiments consist of the following five ones: CNTL experiment (control experiment), and TMBT experiment, BDMT experiment and ALL experiment that set the terrain altitude of Taeback Mountains and Northern mountain complex as zero, respectively, and the altitude of the above-mentioned two mountains as zero, and LANDSEA experiment that set to change the Korean Peninsula into sea in order to find out the land-sea thermal contrast effect. These experiment results showed that a cold air current stemming from the Siberian high pressure met the group of northern mountains with high topography altitude and was separated into two air currents. These two separated air currents met each other again on the Middle and Northern East Sea, downstream of the group of northern mountains and converged finally, creating the convergent cloud band. And these experiments suggested that the convergent cloud band located on the Middle and Northern East Sea, and the cloud band lying on the southern East sea to the coastal waters of the Japanese Island facing the East Sea, were generated and developed by different dynamical mechanisms. Also it was found that the topography of Taeback Mountains created a warm air advection region due to temperature rise by adiabatic compression near the coastal waters of Yeongdong Region, downstream of the mountains. In conclusion, these experiment results clearly showed that the most essential factor having an effect on the generation and development of the convergent cloud band was the topography effect of the northern mountain complex, and that the land-sea thermal contrast effect was insignificant.
Development and Evaluation of the High Resolution Limited Area Ensemble Prediction System in the Korea Meteorological Administration
Kim, SeHyun ; Kim, Hyun Mee ; Kay, Jun Kyung ; Lee, Seung-Woo ;
Atmosphere, volume 25, issue 1, 2015, Pages 67~83
DOI : 10.14191/Atmos.2015.25.1.067
Predicting the location and intensity of precipitation still remains a main issue in numerical weather prediction (NWP). Resolution is a very important component of precipitation forecasts in NWP. Compared with a lower resolution model, a higher resolution model can predict small scale (i.e., storm scale) precipitation and depict convection structures more precisely. In addition, an ensemble technique can be used to improve the precipitation forecast because it can estimate uncertainties associated with forecasts. Therefore, NWP using both a higher resolution model and ensemble technique is expected to represent inherent uncertainties of convective scale motion better and lead to improved forecasts. In this study, the limited area ensemble prediction system for the convective-scale (i.e., high resolution) operational Unified Model (UM) in Korea Meteorological Administration (KMA) was developed and evaluated for the ensemble forecasts during August 2012. The model domain covers the limited area over the Korean Peninsula. The high resolution limited area ensemble prediction system developed showed good skill in predicting precipitation, wind, and temperature at the surface as well as meteorological variables at 500 and 850 hPa. To investigate which combination of horizontal resolution and ensemble member is most skillful, the system was run with three different horizontal resolutions (1.5, 2, and 3 km) and ensemble members (8, 12, and 16), and the forecasts from the experiments were evaluated. To assess the quantitative precipitation forecast (QPF) skill of the system, the precipitation forecasts for two heavy rainfall cases during the study period were analyzed using the Fractions Skill Score (FSS) and Probability Matching (PM) method. The PM method was effective in representing the intensity of precipitation and the FSS was effective in verifying the precipitation forecast for the high resolution limited area ensemble prediction system in KMA.
Global Carbon Budget Changes under RCP Scenarios in HadGEM2-CC
Heo, Tae-Kyung ; Boo, Kyung-On ; Shim, Sungbo ; Hong, Jinkyu ; Hong, Je-Woo ;
Atmosphere, volume 25, issue 1, 2015, Pages 85~97
DOI : 10.14191/Atmos.2015.25.1.085
This study is to investigate future changes in carbon cycle using the HadGEM2-Carbon Cycle simulations driven by
emissions. For experiment, global carbon budget is integrated from the two (8.5/2.6) representative concentration pathways (RCPs) for the period of 1860~2100 by Hadley Centre Global Environmental Model, version 2, Carbon Cycle (Had-GEM2-CC). From 1985 to 2005, total cumulative
amount of anthropogenic emission prescribed as 156 GtC. The amount matches to the observed estimates (CDIAC) over the same period (136 GtC). As
emissions into the atmosphere increase, the similar increasing tendency is found in the simulated atmospheric
concentration and temperature. Atmospheric
concentration in the simulation is projected to be 430 ppm for RCP 2.6 at the end of the twenty-first century and as high as 931 ppm for RCP 8.5. Simulated global mean temperature is expected to rise by
for RCP 2.6 and 8.5, respectively. Land and ocean carbon uptakes also increase in proportion to the
emissions of RCPs. The fractions of the amount of
stored in atmosphere, land, and ocean are different in RCP 8.5 and 2.6. Further study is needed for reducing the simulation uncertainty based on multiple model simulations.
A Sensitivity Study of WRF Model Simulations to Nudging Methods for A Yeongdong Heavy Snowfall Event
Choi, Ji Won ; Lee, Jae Gyoo ;
Atmosphere, volume 25, issue 1, 2015, Pages 99~115
DOI : 10.14191/Atmos.2015.25.1.099
To investigate the influences of the observational nudging and the analysis nudging on the WRF simulation for the heavy snowfall event in Yeongdong area on 26 February 2012, the sensitivity experiments in relation to nudging effects were conducted. We initially set the magnitude of nudging coefficient of
to apply to the analysis nudging experiments and observational experiments. To select the optimized options for the observational nudging, the radius influence experiment was carried out with radii ranging from 10 to 25 km at 5 km intervals. Among the observational nudging experiments, the experiment, which was conducted with the option of the radius influence of 15 km and that of the nudging coefficient of
(ONG exp.), showed a best result. As giving the nudging effect only directly on D1 and D2 brought about a better result for the analysis nudging, we set the analysis nudging experiment as above (ANG exp.). We compared and analyzed the results from the control experiment, ONG experiment, and ANG experiment to reveal nudging effects. It was found that the control experiment brought about a result that it overestimated its precipitation in comparison with the observation and failed to properly simulate the time zone of rainfall concentration. When either of the two nudging (observational and analysis nudging) was applied to the data assimilation, it brought about a better result than the control experiment. Especially the observational nudging led to a meaningful result for the wind field, while the analysis nudging had the best result for the precipitation distribution among the experiments.
Analyses of the OMI Cloud Retrieval Data and Evaluation of Its Impact on Ozone Retrieval
Choi, Suhwan ; Bak, Juseon ; Kim, JaeHwan ; Baek, KangHyun ;
Atmosphere, volume 25, issue 1, 2015, Pages 117~127
DOI : 10.14191/Atmos.2015.25.1.117
The presences of clouds significantly influence the accuracy of ozone retrievals from satellite measurements. This study focuses on the influence of clouds on Ozone Monitoring instrument (OMI) ozone profile retrieval based on an optimal estimation. There are two operational OMI cloud products; OMCLDO2, based on absorption in
at 477 nm, and OMCLDRR, based on filling in Fraunhofer lines by rotational Raman scattering (RRS) at 350 nm. Firstly, we characterize differences between
and RRS effective cloud pressures using MODIS cloud optical thickness (COT), and then compare ozone profile retrievals with different cloud input data.
cloud pressures are significantly smaller than RRS by ~200 hPa in thin clouds, which corresponds to either low COT or cloud fraction (CF). On the other hand, the effect of Optical centroid pressure (OCP) on ozone retrievals becomes significant at high CF. Tropospheric ozone retrievals could differ by up to
DU with the different cloud inputs. The layer column ozone below 300 hPa shows the cloud-induced ozone retrieval error of more than 20%. Finally, OMI total ozone is validated with respect to Brewer ground-based total ozone. A better agreement is observed when
cloud data are used in OMI ozone profile retrieval algorithm. This is distinctly observed at low OCP and high CF.
A Statistical Analysis of Aviation Turbulence Observed in Pilot Report (PIREP) over East Asia Including South Korea
Lee, Dan-Bi ; Chun, Hye-Yeong ;
Atmosphere, volume 25, issue 1, 2015, Pages 129~140
DOI : 10.14191/Atmos.2015.25.1.129
The statistical analysis of aviation turbulence occurred over South Korea and East Asia regions is performed, using pilot reports (PIREPs) during December 2002~November 2012 that were provided by the Korea Aviation Meteorological Agency (KAMA) and the National Center for Atmospheric Research (NCAR). In South Korea, the light (LGT)- and moderate or greater (MOG)-level turbulence events occurred most frequently in spring and winter due to strong vertical wind shear below or above jet stream in these seasons. Spatially, the LGT- and MOG-level events occurred mainly along domestic flight routes. The higher occurrences of the LGT- and MOG-level convectively induced turbulence (CIT) events show in spring and summer when convective systems frequently affect the Korean peninsula. The results are generally similar to a previous study on the aviation turbulence over South Korea during 2003~2008, except that MOG-level CIT events occurred more in February, June, and October. Over East Asia region, the LGT- and MOG-level events appeared mostly in summer and spring, respectively, and the highest occurrence is over the southeast region of Japan and Kamchatka peninsula near Russia.
Dependence of Total and Carbonaceous Aerosol Concentrations on Transport Pathways in Seoul, Korea
Jeong, Ukkeo ; Kim, Jhoon ; Kim, Young J. ; Jung, Jinsang ;
Atmosphere, volume 25, issue 1, 2015, Pages 141~148
DOI : 10.14191/Atmos.2015.25.1.141
Recently increased anthropogenic aerosols change the radiative energy balance and affect human life. The management of air quality requires monitoring both the local emissions and transported pollutants. In order to estimate the quantitative contribution of long-range transport from remote sources on aerosol concentrations in Seoul, the airmasses were classified into five types with respect to their pathways. When airmass came from west over strong emission regions in China, high concentrations of
, black carbon (BC), organic carbon (OC), and elemental carbon (EC) were found, even higher than those for the stagnated airmass. High OC concentrations were found when airmass came from north while BC, EC, and
concentrations were lower than those of the stagnated airmasses. During dust events, the
concentrations increased significantly while carbonaceous aerosol concentrations did not increased. The temporal variations of aerosol concentrations in Seoul were affected by the seasonal variations of airmass pathways. The high
appeared most frequently when the airmasses came from west.
Development and Validation of the Coupled System of Unified Model (UM) and PArameterized FOG (PAFOG)
Kim, Wonheung ; Yum, Seong Soo ;
Atmosphere, volume 25, issue 1, 2015, Pages 149~154
DOI : 10.14191/Atmos.2015.25.1.149
As an attempt to improve fog predictability at Incheon International Airport (IIA) we couple the 3D weather forecasting model currently operational in Korea Meteorological Administration (regional Unified Model, UM_RE) with a 1D turbulence model (PAFOG). The coupling is done by extracting the meteorological data from the 3D model and properly inserting them in the PAFOG model as initial conditions and external forcing. The initial conditions include surface temperature, 2 m temperature and dew point temperature, geostrophic wind at 850 hPa and vertical profiles of temperature and dew point temperature. Moisture and temperature advections are included as external forcing and updated every hr. To validate the performance of the coupled system, simulation results of the coupled system are compared to those of the 3D model alone for the 22 sea fog cases observed over the Yellow Sea. Three statistical indices, i.e., Root Mean Square Error (RMSE), linear correlation coefficient (R) and Critical Success Index (CSI), are examined, and they all indicate that the coupled system performs better than the 3D model alone. These are certainly promising results but more improvement is required before the coupled system can actually be used as an operational fog forecasting model. For the RMSE, R, and CSI values for the coupled system are still not good enough for operational fog forecast.
Development and Assessment of Dynamical Seasonal Forecast System Using the Cryospheric Variables
Shim, Taehyoun ; Jeong, Jee-Hoon ; Ok, Jung ; Jeong, Hyun-Sook ; Kim, Baek-Min ;
Atmosphere, volume 25, issue 1, 2015, Pages 155~167
DOI : 10.14191/Atmos.2015.25.1.155
A dynamical seasonal prediction system for boreal winter utilizing cryospheric information was developed. Using the Community Atmospheric Model, version3, (CAM3) as a modeling system, newly developed snow depth initialization method and sea ice concentration treatment were implemented to the seasonal prediction system. Daily snow depth analysis field was scaled in order to prevent climate drift problem before initializing model's snow fields and distributed to the model snow-depth layers. To maximize predictability gain from land surface, we applied one-month-long training procedure to the prediction system, which adjusts soil moisture and soil temperature to the imposed snow depth. The sea ice concentration over the Arctic region for prediction period was prescribed with an anomaly-persistent method that considers seasonality of sea ice. Ensemble hindcast experiments starting at 1st of November for the period 1999~2000 were performed and the predictability gain from the imposed cryospheric informations were tested. Large potential predictability gain from the snow information was obtained over large part of high-latitude and of mid-latitude land as a result of strengthened land-atmosphere interaction in the modeling system. Large-scale atmospheric circulation responses associated with the sea ice concentration anomalies were main contributor to the predictability gain.
Estimation of Particle Mass Concentration from Lidar Measurement
Kim, Man-Hae ; Yeo, Huidong ; Sugimoto, Nobuo ; Lim, Han-Cheol ; Lee, Chul-Kyu ; Heo, Bok-Haeng ; Yu, Yung-Suk ; Sohn, Byung-Ju ; Yoon, Soon-Chang ; Kim, Sang-Woo ;
Atmosphere, volume 25, issue 1, 2015, Pages 169~177
DOI : 10.14191/Atmos.2015.25.1.169
Vertical distribution of particle mass concentrations was estimated from 8-year elastic-backscatter lidar and sky radiometer data, and from ground-level PM10 concentrations measured in Seoul. Lidar ratio and mass extinction efficiency were determined from aerosol optical depth (AOD) and ground-level PM10 concentrations, which were used as constraints to estimate particle mass concentration. The mean lidar ratio (with standard deviation) and mass extinction efficiency for the entire 8-year study period were
, respectively. The lidar ratio did not vary significantly with the
exponent (less than
); however, the mass extinction efficiency decreases to
(51% less than the mean value) when the
exponent is less than 0.5. This result implies that the particle mass concentration from lidar measurements can be underestimated for dust events. Seasonal variation of the particle mass concentration estimated from lidar measurements for the boundary layer, was quite different from ground-level PM10 measurements. This can be attributable to an inhomogeneous vertical distribution of aerosol in the boundary layer.
A Prediction of Northeast Asian Summer Precipitation Using Teleconnection
Lee, Kang-Jin ; Kwon, MinHo ;
Atmosphere, volume 25, issue 1, 2015, Pages 179~183
DOI : 10.14191/Atmos.2015.25.1.179
Even though state-of-the-art general circulation models is improved step by step, the seasonal predictability of the East Asian summer monsoon still remains poor. In contrast, the seasonal predictability of western North Pacific and Indian monsoon region using dynamic models is relatively high. This study builds canonical correlation analysis model for seasonal prediction using wind fields over western North Pacific and Indian Ocean from the Global Seasonal Forecasting System version 5 (GloSea5), and then assesses the predictability of so-called hybrid model. In addition, we suggest improvement method for forecast skill by introducing the lagged ensemble technique.
Aerosol Light Absorption and Scattering Coefficient Measurements with a Photoacoustic and Nephelometric Spectrometer
Kim, Ji-Hyoung ; Kim, Sang-Woo ; Heo, Junghwa ; Nam, Jihyun ; Kim, Man-Hae ; Yu, Yung-Suk ; Lim, Han-Chul ; Lee, Chulkyu ; Heo, Bok-Haeng ; Yoon, Soon-Chang ;
Atmosphere, volume 25, issue 1, 2015, Pages 185~191
DOI : 10.14191/Atmos.2015.25.1.185
Ambient measurements of aerosol light absorption (
) and scattering coefficients (
) were done at Gosan climate observatory during summer 2008 using a 3-wavelength photoacoustic soot spectrometer (PASS). PASS was deployed photoacoustic method for light absorption and integrated nephelometry for light scattering measurements. The
from PASS were compared with those from co-located aethalometer and nephelometer measurements. The aethalometer measurements of
correlated reasonably well with photoacoustic measurements, but the slope of the linear fitting line indicated the PASS measurement values of
were larger by a factor of 1.53. The nephelometer measurement values of
correlated very well with PASS measurements of
, with a slope of 1.12 and a small offset. Comparing to the aethalometer measurements, the photoacoustic measurements of
didn't exhibit a significant (i.e., the ratio between aethalometer and PASS increased) change with increasing relative humidity (RH). The ratio of
between nephelometer and PASS increased with increasing RH, especially when the RH increased beyond 80%. This apparent increase in
with RH may be due to the contribution of hygroscopic growth of aerosols.