• Atmosphere
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• v.21 no.4
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• pp.481-495
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• 2011

This study is performed to consider the threshold values of heavy rain warning in Korea using 98 surface meteorological station data and 590 Automatic Weather System stations (AWSs), damage data of National Emergency Management Agency for the period of 2005 to 2009. It is in need to arrange new criteria for heavy rain considering concept of rainfall intensity and rainfall damage to reflect the changed characteristics of rainfall according to the climate change. Rainfall values from the most frequent rainfall damage are at 30 mm/1 hr, 60 mm/3 hr, 70 mm/6 hr, and 110 mm/12 hr, respectively. The cumulative probability of damage occurrences of one in two due to heavy rain shows up at 20 mm/1 hr, 50 mm/3 hr, 80 mm/6 hr, and 110 mm/12 hr, respectively. When the relationship between threshold values of heavy rain warning and the possibility of rainfall damage is investigated, rainfall values for high connectivity between heavy rain warning criteria and the possibility of rainfall damage appear at 30 mm/1 hr, 50 mm/3 hr, 80 mm/6 hr, and 100 m/12 hr, respectively. It is proper to adopt the daily maximum precipitation intensity of 6 and 12 hours, because 6 hours rainfall might be include the concept of rainfall intensity for very-short-term and short-term unexpectedly happened rainfall and 12 hours rainfall could maintain the connectivity of the previous heavy rain warning system and represent long-term continuously happened rainfall. The optimum combinations of criteria for heavy rain warning of 6 and 12 hours are 80 mm/6 hr or 100 mm/12 hr, and 70 mm/6 hr or 110 mm/12 hr.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.670-671
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• 2008

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.382-385
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• 2004

Communication Ocean Meteorological Satellite (COMS) for the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service is planned to be launched onto Geostationary Earth Orbit in 2008 according to the Korea national space program. A feasibility study on the solar constraint in the operation of the COMS meteorological imager (MI) is performed using the GOES imager hardware operation characteristics. The Earth observation areas of the MI are introduced and the observation time of the MI observation area is calculated. The sun light can enter into the MI optical system around the local midnight and impinge on the performance of the MI. The solar eclipse viewed from the satellite occurs near local midnight around the equinox. This study discusses the restriction of imaging operation time that should be considered in order to avoid the solar intrusion about local midnight and to keep acceptable image quality for the MI observation areas. This study could be useful to build the operation concept of the MI during the development of the MI.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1292-1294
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• 2003

This paper presents the results of research and analysis with the satellite-derived snow data. It provides the main climatic characteristics of snow cover in China and shows the variation and distribution of snow in regions of Xinjiang, Inter Mongolia and Tibet plateau. The study reveals the vicissitude periods of winter snow cover in Tibetan Plateau by using wavelet analysis with the data from 1980 to 2001. It has about 10 years large period and 3-5 years small period. The analysis shows that the extension of snow increased in recent years in Xinjiang. The results of analysis proves the relationship between winter snow cover in Tibetan Plateau and next summer precipitation in the middle and lower reaches of the Yangtze River. They have good correlation.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1261-1263
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• 2003

Based on twelve observational stations low meteorological visibility (LMV) data during November 2002 to April 2003, the spatial distribution of LMV over Hongkong area (113.8$^{\circ}$ E-114.4$^{\circ}$ E, 22.1$^{\circ}$ N-22.4$^{\circ}$ N) is studied, using a PCA method. Optical spectrum of NOAA-16 associated with LMV shows that the significant effect factors correlated with LMV in the leading mode are the difference or rate between the visible and near-IR channels and single visible channel. A successful retrieval of LMV is done and a regression equation with a multiple correlation coefficient of 0.67 is obtained.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2012.07a
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• pp.75-78
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• 2012

• Atmosphere
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• v.20 no.3
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• pp.239-246
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• 2010

In this study, the climatological characteristics of the landfall typhoons on North Korea are surveyed to estimate the frequency, the intensity, the track, and their damage. The data for the period of 1951-2008 are used from both RSMC (Regional Specialized Meteorological Center) Tokyo Typhoon Center and NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research), EM-DAT (Emergency Events Database). There are the ten highest frequencies from 1961 to 1965 and is one frequency for the period of both 1966-1979 and 1976-1980 respectively. Even if a clear trend on the frequency of typhoon is not defined, it is noticeable the intensity has been weak since the frequency of TS (Tropical Storm) decreased. In order to figure out both the characteristic of intensity and the relation between the typhoon track and the expansion of North Pacific High (NPH), Typhoon's tracks are classified into three types as follows: (I) landing on the west coast of North Korea through the mainland of China, (II) landing on the west coast of North Korea, (III) landing on a central/eastern part of the Korean peninsula through South Korea. More often than not, the characteristic of Type (I) is the case of a landfall after it becomes extratropical cyclone. Type(II) and Type(III) show a landfall as TS grade, by comparision. On the relation between the typhoon's track and the expansion of NPH analyzed, Type (I) shows the westward expansion while both Type (II) and Type (III) show the northward expansion and development of NPH. This means the intensity of a typhoon landfall on North Korea is variable depending on the development of NPH. Finally, only two cases are found among total five cases in EM-DAT, reportedly that North Korea was damaged. And therefore, the damage by the wind of Prapiroon (the $12^{th}$ typhoon, 2000) and heavy rainfall with Rusa (the $15^{th}$ typhoon, 2002) landing on North Korea was analyzed. Moreover, it is estimated both Prapiroon and Rusa have done badly damaged to North Korea as the economical losses of as much as six billion and five hundred-thousand US dollar, respectively.

• Atmosphere
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• v.29 no.4
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• pp.481-499
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• 2019

National Institute of Meteorological Sciences has conducted a total 54 cloud seeding experiments with a silver iodide and calcium chloride using aircrafts from 2008 to 2018. The goal of the experiments is to improve the techniques of precipitation enhancement in Korea. The cloud seeding experiments using the silver iodide and calcium chloride were 36 and 18 times, respectively. During the cloud seeding experiments of the silver iodide and calcium chloride, the average values of total cloud amount for two kinds of seeding materials were 9.6 for and 8.1, respectively. The cloud type with the highest occurrence was Nimbostratus (Ns)-Stratus (St) (58%) in the silver iodide cloud seeding experiment. It was Altostratus (As)-Stratocumulus (Sc) (44%) in the calcium chloride cloud seeding experiment. Compared to probability of obtaining cloud seeding effect of the experiments using a leased aircraft, the probability using an atmospheric research aircraft increased from 43% to 63% in the silver iodide cloud seeding experiment and from 29% to 75% in the calcium chloride cloud seeding experiment. However, the increasing tendency was only shown during the one year experiment (2018). To get the meaningful statistical tendency of the cloud seeding effects, it is needed to implement many experiments in several years. Further we have to more clearly understand the characteristics of clouds developing in Korea and implement the cloud seeding experiments under a variety of weather conditions in order to develop the optimized precipitation enhancement technology in Korea.

• Korean Journal of Remote Sensing
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• v.34 no.1
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• pp.1-15
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• 2018

Passive microwave sea surface temperatures (SST) were validated in the Northwest Pacific using a total of 102,294 collocated matchup data between Global Precipitation Measurement (GPM) / GPM Microwave Sensor(GMI) data and oceanic in-situ temperature measurements from March 2014 to December 2016. A root-mean-square (RMS) error and a bias error of the GMI SST measurements were evaluated to $0.93^{\circ}C$ and $0.05^{\circ}C$, respectively. The SST differences between GMI and in-situ measurements were caused by various factors such as wind speed, columnar atmospheric water vapor, land contamination near coastline or islands. The GMI SSTs were found to be higher than the in-situ temperature measurements at low wind speed (<6 m/s) during the daytime. As the wind speed increased at night, SST errors showed positive bias. In addition, other factors, coming from atmospheric water vapor, sensitivity degradation at a low temperature range, and land contamination, also contributed to the errors. One of remarkable characteristics of the errors was their latitudinal dependence with large errors at high latitudes above $30^{\circ}N$. Seasonal characteristics revealed that the errors were most frequently observed in winter with a significant positive deviation. This implies that SST errors tend to be large under conditions of high wind speeds and low SSTs. Understanding of microwave SST errors in this study is anticipated to compensate less temporal capability of Infrared SSTs and to contribute to increase a satellite observation rate with time, especially in SST composite process.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.163-172
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• 2013

Communication Ocean Meteorological Satellite (COMS) has the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service. The COMS is located at $128.2^{\circ}$ East longitude on the geostationary orbit and currently under normal operation service since April 2011. For the sake of the executions of the meteorological and the ocean mission as well as the satellite control and management, the satellite mission planning is daily performed. The satellite mission plans are sent to the satellite by the real-time operation and the satellite executes the missions as per the mission plans. In this paper the mission planning for COMS normal operation is discussed in terms of the ground station configuration and the characteristics of daily, weekly, monthly, and seasonal mission planning activities. The successful mission planning is also confirmed with the first one-year normal operation results.