• Atmosphere
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• v.24 no.2
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• pp.173-188
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• 2014

The KMA has cooperated with the Oklahoma University in USA to develop a Polarimetric Radar Data (PRD) simulator to improve the microphysical processes in Korea Local Analysis and Prediction System (KLAPS), which is critical for the utilization of PRD into Numerical Weather Prediction (NWP) field. The simulator is like a tool to convert NWP data into PRD, so it enables us to compare NWP data with PRD directly. The simulator can simulate polarimetric radar variables such as reflectivity (Z), differential reflectivity ($Z_{DR}$), specific differential phase ($K_{DP}$), and cross-correlation coefficient (${\rho}_{hv}$) with input of the Drop Size Distribution (DSD) and scattering calculation of the hydrometeors. However, the simulator is being developed based on the foreign observation data, therefore the PRD simulator development reflecting rainfall characteristics of Korea is needed. This study analyzed a potential application of the 2-Dimension Video Disdrometer (2DVD) data by calculating the raindrop axis ratio according to the rain-types to reflect Korea's rainfall characteristics into scattering module in the simulator. The 2DVD instrument measures the precipitation DSD including the fall velocity and the shape of individual raindrops. We calculated raindrop axis ratio for stratiform, convective and mixed rainfall cases after checking the accuracy of 2DVD data, which usually represent the scattering characteristics of precipitation. The raindrop axis ratio obtained from 2DVD data are compared with those from foreign database in the simulator. The calculated the dual-polarimetric radar variables from the simulator using the obtained raindrop axis ratio are also compared with in situ dual-polarimetric observation data at Bislsan (BSL). 2DVD observation data show high accuracies in the range of 0.7~4.8% compared with in situ rain gauge data which represents 2DVD data are sufficient for the use to simulator. There are small differences of axis ratio in the diameter below 1~2 mm and above 4~5 mm, which are more obvious for bigger raindrops especially for a strong convective rainfall case. These differences of raindrop axis ratio between domestic and foreign rainfall data base suggest that the potential use of disdrometer observation can develop of a PRD simulated suitable to the Korea precipitation system.

• New & Renewable Energy
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• v.7 no.1
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• pp.22-28
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• 2011

The surface solar radiations were calculated and analyzed with spatial resolutions (4 km and 1 km) using by GWNU (Gangneung-Wonju National University) solar radiation model. The GWNU solar radiation model is used various data such as aerosol optical thickness, ozone amount, total precipitable water and cloud factor are retrieved from Moderate Resolution Imaging Spectrometer (MODIS), Ozone Monitoring Instrument (OMI), MTSAT-1R satellite data and output of the Regional Data Assimilation Prediction System(RDAPS) model by Korea Meteorological Administration (KMA), respectively. The differences of spatial resolutions were analyzed with input data (especially, cloud factor from MTSAT-1R satellite). And the Maximum solar radiation by GWNU model were found in Andong, Daegu and Jinju regions and these results were corresponded with the MTSAT-1R cloud factor.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E4
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• pp.169-181
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• 2001

To test the compatibility of differential optical absorption spectroscopy (DOAS) and conventional in-situ monitoring technique we conducted a comparative analysis of the two systems using hourly measurement data sets of three criteria pollutants including No$_{2}$O$_{3}$, and SO$_{2}$ collected in months between April and June of 2001 at Sung Man city, Kyung Gi Province, Korea. The results of our comparative analysis were useful to evaluate the various aspects of DOAS performance, of particular the level of agreement with the counterpart method through computation of percent differences and correlation analysis. Interpretation of the mixing ratio data for those chemical species was however confined in terms of explaining the differences affected by the changes in environmental conditions because measurements of important meteorological parameters were limited during most of the study period. Nevertheless, the overall results of this study strongly demonstrated that the mixing ratio of major pollutants measured by the two different systems maintain strong compatibility from various respects.

• Journal of Sensor Science and Technology
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• v.15 no.6
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• pp.442-448
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• 2006

Ultrasonic anemometers using pulse envelope detection-based method are standard instruments in most meteorological studies. In this paper, a new phase measurement method is tried to achieve the enhanced resolution without changing dimensions. The measurement sensitivity, dynamic range, and measurement speed of the new instrument are 0.2 mm/s, 13.3 m/s, and 13 measurements/sec, respectively. A graphic user interface is added to show the velocity and direction of the wind with the speed of sound and temperature of the wind in the 3 dimensional space. The new anemometer could be useful for the measurement of the air speed, the flow of fluids, and even air flow inside the downtown buildings.

• The Journal of the Acoustical Society of Korea
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• v.31 no.4
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• pp.253-259
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• 2012

Goldingham's measurement of the velocity of sound undertaken in the early nineteenth century was the first large-scale measuring enterprise which considered various meteorological factors such as temperature, humidity, atmospheric pressure, the direction of the wind, etc. Goldingham's successful performance of measuring the velocity of sound by employing the sounds of cannons as sound source in Madras (now Chennai), a colonial region of India, for one and a half years was supported by material, institutional and social resources. As the official astronomer at the Madras Observatory, he was benefitted by the undemanding employment of accurate measuring instruments under the support of the Madras Army enabled him to gain reliable data and his reputation as professional experimentalist facilitated the acknowledgment of their trustworthiness.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.191-195
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• 2008

In Ansan (the headquarter of KORDI ; Korea Ocean Research & Development Institute), KOSC(Korea Ocean Satellite Center) is being prepared for acquisition, processing and distribution of sensor data via L-band from GOCI(Geostationary Ocean Color Imager) instrument which is loaded on COMS(Communication, Ocean and Meteorological Satellite); it will be launched in 2009. The basis equipment of KOSC(Electric power, Network, Security) has been constructed in 2007. KOSC is being constructed data processing and management system, GOCI L-band reception system, etc. The final object of KOSC is that maximize the application of GOCI.

• Atmosphere
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• v.32 no.1
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• pp.27-37
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• 2022

The Korean Integrated Model (KIM) forecast system was extended to assimilate Horizontal Line-Of-Sight (HLOS) wind observations from the Atmospheric Laser Doppler Instrument (ALADIN) on board the Atmospheric Dynamic Mission (ADM)-Aeolus satellite. Quality control procedures were developed to assess the HLOS wind data quality, and observation operators added to the KIM three-dimensional variational data assimilation system to support the new observed variables. In a global cycling experiment, assimilation of ALADIN observations led to reductions in average root-mean-square error of 2.1% and 1.3% for the zonal and meridional wind analyses when compared against European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS) analyses. Even though the observable variable is wind, the assimilation of ALADIN observation had an overall positive impact on the analyses of other variables, such as temperature and specific humidity. As a result, the KIM 72-hour wind forecast fields were improved in the Southern Hemisphere poleward of 30 degrees.

• Atmosphere
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• v.29 no.1
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• pp.13-20
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• 2019

Since 1985, the Dobson Spectrophotometer has been operated at Yonsei University, and this instrument has monitored the daily representative total ozone in Seoul. Climatological value for total ozone in Seoul is updated by using the daily representative observation data from 1985 to 2017. After updating the daily representative total ozone data, seasonal and inter-annual variation of total ozone in Seoul is also estimated after calculating inter-comparison between ground (Dobson Spectrophotometer) and satellite [Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI)] observations. The global average of total ozone measured by satellite is 297 DU, and its recent amount is about 3.5% lower than the global amount in 1980s. In Seoul, daily representative total ozone is ranged from 225 DU to 518 DU with longterm mean value of 324.3 DU. In addition, monthly mean total ozone is estimated from 290 DU (October) to 362 DU (March), and yearly average of total ozone have been continuously increased since 1985. For the long-term trend of total ozone in Seoul, this study is considered the seasonal variation, Solar Cycle, and Quasi-Biennial Oscillation. In addition to the natural oscillation effect, this study also considered to the long-term variation of sudden increase of total ozone due to the secondary ozone peak. By considering these natural effects, the long-term total ozone trends from 1985 to 2017 are estimated to be 1.11~1.46%/decade.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.334-334
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• 2022

Improvement of old-fashioned rain gauge systems for automatic, timely, continuous, and accurate precipitation observation is highly essential for weather/climate prediction and natural hazards early warning, since the occurrence frequency and intensity of heavy and extreme precipitation events (especially floods) are recently getting more increase and severe worldwide due to climate change. Although rain gauge accuracy of 0.1 mm is recommended by the World Meteorological Organization (WMO), the traditional rain gauges in both weighting and tipping bucket types are often unable to meet that demand due to several existing technical limitations together with higher production and maintenance costs. Therefore, we aim to introduce a newly developed and cost-effective hybrid rain gauge system at 0.1 mm accuracy that combines advantages of weighting and tipping bucket types for continuous, automatic, and accurate precipitation observation, where the errors from long-term load cells and external environmental sources (e.g., winds) can be removed via an automatic drainage system and artificial intelligence-based data quality control procedure. Our rain gauge system consists of an instrument unit for measuring precipitation, a communication unit for transmitting and receiving measured precipitation signals, and a database unit for storing, processing, and analyzing precipitation data. This newly developed rain gauge was designed according to the weather instrument criteria, where precipitation amounts filled into the tipping bucket are measured considering the receiver's diameter, the maximum measurement of precipitation, drainage time, and the conductivity marking. Moreover, it is also designed to transmit the measured precipitation data stored in the PCB through RS232, RS485, and TCP/IP, together with connecting to the data logger to enable data collection and analysis based on user needs. Preliminary results from a comparison with an existing 1.0-mm tipping bucket rain gauge indicated that our developed rain gauge has an excellent performance in continuous precipitation observation with higher measurement accuracy, more correct precipitation days observed (120 days), and a lower error of roughly 27 mm occurred during the measurement period.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1077-1089
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• 2022

With the construction of Seoul National University (SNU), the Mt. Gwanak watershed has undergone some urbanization. As with other campus catchments, data related to the water cycle is extremely limited. Therefore, this study began by collecting hydrological and meteorological data using Atmos-41, a complex meteorological observation instrument. The observation results of Atmos-41 were validated by analyzing the statistical characteristics and confidence intervals based on the monthly variability of data from the Korea Meteorological Administration. Results of the previous research were used to validate the simulated surface runoff and infiltration using the Storm Water Management Model (SWMM). The potential evapotranspiration (PET) simulated by the SWMM was rectified by comparing it to the Atmos-41 observation data. Multiple regression analysis was employed to adjust for the fluctuations in precipitation, relative humidity, and wind speed because the calculated SWMM PET tends to be underestimated during periods of low temperatures. R² increased from 0.54 to 0.80 when compared to the Atmos-41 PET. The rate of change in the water cycle as a consequence of the SNU's construction resulted in a 15.7% increase in surface runoff, a 14.2% decrease in infiltration rate, and a 1.6% decrease in evaporation.