• Journal of Astronomy and Space Sciences
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• 제29권3호
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• pp.295-303
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• 2012

In this study, we compared the precipitable water vapor (PWV) data derived from the radiosonde observation data at Sokcho Observatory and the PWV data at Sokcho Global Positioning System (GPS) Observatory provided by Korea Astronomy and Space Science Institute, for the years of 2006, 2008, 2010, and analyzed the radiosonde seasonal, diurnal bias according to radiosonde sensor types. In the scatter diagram of the daytime and nighttime radiosonde PWV data and the GPS PWV data, dry bias was found in the daytime radiosonde observation as known in the previous study. Overall, the tendency that the wet bias of the radiosonde PWV increased as the GPS PWV decreased and the dry bias of the radiosonde PWV increased as the GPS PWV increased. The quantitative analysis of the bias and error of the radiosonde PWV data showed that the mean bias decreased in the nighttime except for 2006 winter, and in comparison for summer, RS92-SGP sensor showed the highest quality.

• 대기
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• 제29권3호
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• pp.283-294
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• 2019

For the upper air observations, a temperature measurement using radiosonde is a common method, and the compensation of solar radiation effects in the radiosonde temperature sensor is an important factor. In this paper, we present various experiments and compensation methods of the radiosonde temperature sensor to overcome the errors caused by the movement of the radiosonde rotation, etc. The methods and procedures of this study are as follows. First, we used the solar simulator to analyze the temperature variation and solar effect of the temperature sensor in the radiosonde according to the insolation. We also analyzed the temperature variation and solar effect of the temperature sensor according to the incident angle between the solar simulator and radiosonde. Second, we measured and analyzed solar radiation absorbed by solar cells attached to radiosonde. Third, we present combined compensate solution of the first and the second experiment results, to overcome errors caused by insolation effects in the radiosonde temperature sensors. Fourth, we compared that the reference temperature in similar environment with the upper air conditions, to verify the new radiated compensation performance of the radiosonde temperature sensor. Finally, the radiosonde fabricated in this study was raised to the atmosphere, and the laser correction algorithm proposed through experiments was reviewed. As a result of the radiosonde SRS-10 produced in this study, the temperature deviation from Vaisala RS92 was $0.057^{\circ}C$ in nighttime observation, $0.17^{\circ}C$ in daytime observation, It is expected that the GRUAN under WMO will be able to obtain a high test rating of 5.0.

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.367-375
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• 2010

In this study, we compared the precipitable water vapor (PWV) data derived from the radiosonde observation data at Sokcho Observatory and the PWV data at Sokcho Global Positioning System (GPS) Observatory provided by Korea Astronomy and Space Science Institute, from 0000 UTC, June 1, 2007 to 1200 UTC, May 31, 2009, and analyzed the radiosonde bias between the day and the night. In the scatter diagram of the daytime and nighttime radiosonde PWV data and the GPS PWV data, dry bias was found in the daytime radiosonde observation as known in the previous study. In addition, for all the rainfall events, the tendency that the wet bias of the radiosonde PWV increased as the GPS PWV decreased and the dry bias of the radiosonde PWV increased as the GPS PWV increased was significantly less distinctive in nighttime than in daytime. The quantitative analysis of the bias and error of the radiosonde PWV data showed that the mean bias decreased in the second year, regardless of nighttime or daytime rainfall, and the non-rainfall root mean square error (RMSE) was similar to that of the previous studies, while the rainfall RMSE was larger to a certain extent.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.491-495
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• 1999

We compared the satellite observed temperature with the radiosonde observed temperature in the Korean Peninsula. The radiosonde observed data were obtained from four upper air observation stations in the Korean Peninsula from 1981 to 1998, and that was compared with the satellite observed data of the channel-2 and channel-4 of microwave sounding unit(MSU) on board NOAA series of polar-orbiting satellites. The radiosonde data were reconstructed into monthly radiosonde T$_{b}$ using MSU weighting function. The monthly climatology shows radiosonde T$_{b2}$ is higher than MSU T$_{b2}$ in summer. The correlation between MSU T$_{b2}$ and radiosonde T$_{b2}$ is 0.72-0.76 and 0.73-0.81 between MSU T$_{b4}$ and radiosonde T$_{b4}$.

• 대기
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• 제19권2호
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• pp.213-226
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• 2009

In order to investigate the characteristics of Changma over the Korean peninsula, KEOP-2007 IOP (Intensive Observing Period) was conducted from 15 June 2007 to 15 July 2007. KEOP-2007 IOP is high spatial and temporal radiosonde observations (RAOB) which consisted of three special stations (Munsan, Haenam, and Ieodo) from National Institute of Meteorological Research, five operational stations (Sokcho, Baengnyeongdo, Pohang, Heuksando, and Gosan) from Korea Meteorological Administration (KMA), and two operational stations (Osan and Gwangju) from Korean Air Force (KAF) using four different types of radiosonde sensors. The error statistics of the sensor of radiosonde were investigated using quality control check. The minimum and maximum error frequency appears at the sensor of RS92-SGP and RS1524L respectively. The error frequency of DFM-06 tends to increase below 200 hPa but RS80-15L and RS1524L show vice versa. Especially, the error frequency of RS1524L tends to increase rapidly over 200 hPa. Systematic biases of radiosonde show warm biases in case of temperature and dry biases in case of relative humidity compared with ECMWF (European Center for Medium-Range Weather Forecast) analysis data and precipitable water vapor from GPS. The maximum and minimum values of systematic bias appear at the sensor of DFM-06 and RS92-SGP in case of temperature and RS80-15L and DFM-06 in case of relative humidity. The systematic warm and dry biases at all sensors tend to increase during daytime than nighttime because air temperature around sensor increases from the solar heating during daytime. Systematic biases of radiosonde are affected by the sensor type and the height of the sun but random errors are more correlated with the moisture conditions at each observation station.

• 대한원격탐사학회지
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• 제16권1호
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• pp.47-54
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• 2000

한반도 기후 분석에 마이크로파 위성자료의 이용을 위해 1981년에서 1998년까지 18년간 한반도 4개의 고층 관측 지점에서 얻어진 온도자료와 위성자료를 비교하였다. 위성자료로 극궤도 위성인 NOAA위성에 탑재되어 있는 MSU(Microwave Sounding Unit) 채널 2와 채널 4 휘도온도를 이용하였다. 고층 관측소의 라디오존데 자료는 MSU 휘도온도와 비교하기위해 MSU 가중함수를 이용하여 고도마다 가중을 두어 월평균 온도 값을 만들어내었다. 월평균 기후값 비교에서 여름철에 라디오존데 온도가 MSU 휘도온도보다 높은 온도를 보였다. 두 온도사이의 상관에서는 채널2의 경우 0.72 - 0.76, 채널 4에서는 0.73 - 0.81정도를 보였다 18년 동안의 온도경향은 채널 2의 경우는 0.04$^{\circ}C$/year의 증가가 있었고, 채널 4의 경우는 -0.07$^{\circ}C$/year의 감소가 보였다.

• 한국항공운항학회지
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• 제15권4호
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• pp.94-99
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• 2007

The purpose of this study is analysis of aircraft turbulence of mid Korea using VWS from Osan radiosonde data and comparison with the PIREPs reporting the aircraft turbulence during $1990{\sim}1999$. The results of this study summarized that the frequence of aircraft events is more higher in winter time and in lower level(near the surface) of the atmosphere from VWS analysis using radiosonde data. And comparison with PIREPs data shows that relatively high skill score(44%) using the VWS method. It appears that the operational forecast skill score of aircraft turbulence is much higher using VWS than empirical method, due to the upgrade of the discrimination criteria of the aircraft turbulence.

• Journal of Astronomy and Space Sciences
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• 제27권3호
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• pp.213-220
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• 2010

As an observation instrument of the longest record of tropospheric water vapor, radiosonde data provide upper-air pressure (geopotential height), temperature, humidity and wind. However, the data have some well-known elements related to inaccuracy. In this article, radiosonde precipitable water vapor (PWV) at Sokcho observatory was compared with global positioning system (GPS) PWV during each summertime of year 2007 and 2008 and the biases were calculated. As a result, the mean bias showed negative values regardless of the rainfall occurrence. In addition, on the basis of GPS PWV, the maximum root mean square error (RMSE) was 5.67 mm over the radiosonde PWV.

• 대한원격탐사학회지
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• 제32권3호
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• pp.263-274
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• 2016

이 연구에서는 2007년에서 2014년까지의 여름철에 대해 속초기상대 라디오존데 관측을 통해 산출된 가강수량과 속초 GNSS 관측소의 가강수량을 비교하였다. 라디오존데 센서 유형별 수증기량 관측 자료가 주야간 및 강수 발생 유무에 따라 어떠한 특성을 가지는지 분석하였다. 두 관측기기의 주간, 야간별 관측 시점에 따른 가강수량 산포도에서는 선행 연구에서 알려진 바와 같이 주간의 라디오존데 관측에서는 건조 편향이 발견되었다. 특히 RSG-20A 센서는 주간, 야간에서 다른 센서에 비해 건조 편향이 크게 나타났다. 또한 전반적으로 GNSS 가강수량이 증가함에 따라 라디오존데 가강수량이 GNSS 가강수량에 대해 과대 추정에서 과소 추정으로 변화하는 경향이 발견되었다. 라디오존데 가강수량의 편향 및 오차에 대한 정량적 분석에서는 2007, 2008년을 제외하고는 센서 종류에 상관없이 여름의 주간에 비해 야간에서 더 작은 평균 편향을 가짐을 확인할 수 있다. 여름철 강수의 유무에 따른 비교에서는 RS92-SGP 센서가 가장 뛰어난 품질의 결과를 보였다.

• 대기
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• 제21권2호
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• pp.185-196
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• 2011

The performance assessment in radiosonde observation on the special observation program (ProbeX-2009) is performed and the characteristics of precipitation using Auto Weather System (AWS) and radiosonde data in 2009 at the Ulleungdo are investigated. The launching time, observation time, and maximum altitude of radiosonde are satisfied with the regulation from Korea Meteorological Administration (KMA) and World Meteorological Organization (WMO) but the duration of observational time of radiosonde is much shorter than that of the ProbeX-2007 because the altitude of launching site is higher than others in 2007. From the analysis of trajectories of radiosonde, most radiosondes at the Ulleungdo tend to move into the east because the westerly prevail at the middle latitude. However, when the Okhotsk high is expanded to the Korean peninsula and the north-westerly winds strengthen over the East Sea as the subtropical high is retreated, radiosonde tends to move into the south-west and south-east, respectively. Maximum distance appears at the end of observation level before May but the level of maximum distance is changed into 100 hPa after June because the prevailing wind direction is reversed from westerly to easterly at the stratosphere during summer time. The condition of precipitation was more correlated with the dynamic instability except Changma season. Precipitation in 2009 at the Ulleungdo occurred under the marine climate so that total precipitation amounts and precipitation intensity were increased and intensified during nighttime. The local environment favorable for the precipitation during nighttime was while the wind speed at the surface and the inflow from the shoreline were strengthened. Precipitation events also affected by synoptic condition but the localized effect induced by topography was more strengthened at the northern part of Ulleungdo.