• Atmosphere
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• v.23 no.3
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• pp.265-273
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• 2013

To investigate properties of cloud and rainfall occurred at Boseong on 10 July 2012, Raindrop Size distributions (RSDs) and other parameters were analyzed using observation data collected by Micro Rain Radar (MRR) and PARticle SIze and VELocity (PARSIVEL) disdrometer located in the National center for intensive observation of severe weather at Boseong in the southwest of the Korean peninsula. In addition, time series of RSD parameters, relationship between reflectivity-rain rate, and vertical variation of rain rates-fall velocities below melting layer were examined. As a result, good agreements were found in the reflectivity-rain rate time series as well as their power relationships between MRR and PARSIVEL disdrometer. The rain rate was proportional to reflectivity, mean diameter, and inversely proportional to shape (${\mu}$), slope (${\Lambda}$), intercept ($N_0$) parameter of RSD. In comparison of the RSD, as rain rate was increased, the slope of RSD became less steep and the mean diameter became larger. Also, it was verified that reflectivities are classified in three categories (Category 1: Z (reflectivity) > 40 dBZ, Category 2: 30 dBZ < Z < 40 dBZ, Category 3: Z < 30 dBZ). As reflectivity was increased, rain rate was intensified and larger raindrops were existed, while reflectivity was decreased, shape (${\mu}$), slope (${\Lambda}$), intercept ($N_0$) parameter of RSD were increased. We expected that these results will lead to better understanding of microphysical process in convective rainfall system occurred during short-term period over Korean peninsula.

• Journal of Korea Water Resources Association
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• v.47 no.9
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• pp.801-812
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• 2014

In this study, average rainfall of basin was estimated and compared with that obtained from Biseulsan dual polarization RADAR. And the runoffs are estimated using Vflo distribution model for Habcheon reservoir basin and Huicheon basin. In the rainfall estimation using dual polarization RADAR, the rainfall was estimated by using the specific phase difference and differential reflectivity of dual polarization RADAR variables. As a result, for all events rainfall estimation using dual polarization RADAR has the closest value to the gauge rainfall in terms of the peak rainfall and total rainfall. Also, runoff simulation results from dual polarization RADAR show the better results. It is concluded that the method using dual polarization radar can improve the accuracy more than a single polarization radar using only horizontal reflectivity.

• Journal of the Korean earth science society
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• v.32 no.1
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• pp.33-45
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• 2011

The characteristics and vertical structure of the rainfall are examined in terms of rain types using TRMM (Tropical Rainfall Measuring Mission) PR (Precipitation Radar) data during the JJA period of 2002-2006 over three different regions; midlatitude region around the Korean Peninsula (EA1), subtropical East Asia (EA2), and tropical East Asia (EA3). The convective rain fraction in the EA1 region is 12.2%, which is smaller by 6% than those in the EA2 and EA3 regions. EA1 shows less frequent convective rain events, which are about 0.5 times as many as those in EA3. EA1 produces the mean convective rain rate of 10.4 mm/h that is about 40% larger than EA2 and EA3 while all regions have similar mean stratiform rain rate. The relationships between storm height and rain rate indicate that the rain rate is proportional to the storm height. Based on the vertical structure of radar reflectivity, EA1 produces deeper and stronger convective clouds with higher rain rate compared to the other regions. In EA3, radar reflectivity increases distinctly toward the land surface at altitude below 5 km, indicating more dominant coalescence-collision processes than the other regions. Furthermore, the bright band of stratiform rain clouds in EA3 is very distinct. In convective rain clouds, the first EOFs of radar reflectivity profiles are similar among the three regions, while the second EOFs are slightly different. The larger variability exists at upper layers for EA1 while it exits at lower levels for EA3.

• Proceedings of the Korea Water Resources Association Conference
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• 2002.05b
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• pp.1246-1250
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• 2002

• Proceedings of the Korea Water Resources Association Conference
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• 2003.05b
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• pp.723-726
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• 2003

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.4
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• pp.1-8
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• 2002

Comparison between the Tropical Rainfall Measuring Mission(TRMM)/Precipitation Radar(PR) and the C-band doppler radar at Cheju, Kunsan and Pusan, operated by the Korean Meteorological Administration (KMA), is conducted for validation of the surface precipitation structure, and for calibration of KMA radar instrument. Data used in validation was selected for seven rain events in the south region of about $36^{\circ}N$ and at TRMM overflight in Korea, during the summer season of 2000. Quantitatively comparing radar reflectivities from two different platforms that have different view angles, bandwidths and frequencies is a challenging task. For the comparison, the precipitation patterns are projected on the same area for TRMM PR. Through the comparison, it is realized that the reflectivity from ground-based radar is under estimated, compared to TRMM/PR observations. We discuss that is underestimation may be produced by many factors(system performance, topography, etc).

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.275-275
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• 2021

A fixed Z-R relationship approach, such as the Marshall-Palmer relationship, for an entire year and for different seasons can be problematic in cases where the relationship varies spatially and temporally throughout a region. From this perspective, this study explores the use of long-term radar reflectivity for South Korea to obtain a nationwide calibrated Z-R relationship and the associated uncertainties within a Bayesian regression framework. This study also investigates seasonal differences in the Z-R relationship and their roles in reducing systematic error. Distinct differences in the Z-R parameters in space are identified, and more importantly, an inverse relationship between the parameters is clearly identified with distinct regimes based on the seasons. A spatially structured pattern in the parameters exists, particularly parameter α for the wet season and parameter β for the dry season. A pronounced region of high values during the wet and dry seasons may be partially associated with storm movements in that season. Finally, the radar rainfall estimates through the calibrated Z-R relationship are compared with the existing Z-R relationships for estimating stratiform rainfall and convective rainfall. Overall, the radar rainfall fields based on the proposed modeling procedure are similar to the observed rainfall fields, whereas the radar rainfall fields obtained from the existing Marshall-Palmer Z-R relationship show a systematic underestimation. The obtained Z-R relationships are validated by testing the predictions on unseen radar-gauge pairs in the year 2018, in the context of cross-validation. The cross-validation results are largely similar to those in the calibration process, suggesting that the derived Z-R relationships fit the radar-gauge pairs reasonably well.

• Journal of Multimedia Information System
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• v.5 no.4
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• pp.245-256
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• 2018

This study estimated rainfall information more effectively by image signals through the information system of weather radar. Based on this, we suggest the way to estimate quantitative precipitation utilizing overlapped observation area of radars. We used the overlapped observation range of ground hyetometer observation network and radar observation network which are dense in our country. We chose the southern coast where precipitation entered from seaside is quite frequent and used Sungsan radar installed in Jeju island and Gudoksan radar installed in the southern coast area. We used the rainy season data generated in 2010 as the precipitation data. As a result, we found a reflectivity bias between two radar located in different area and developed the new quantitative precipitation estimation method using the bias. Estimated radar rainfall from this method showed the apt radar rainfall estimate than the other results from conventional method at overall rainfall field.

• Journal of information and communication convergence engineering
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• v.4 no.1
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• pp.46-52
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• 2006

Precipitation measurement with ground-based radar needs an information of the raindrop size distribution (RSD) characteristics. A 10-month dataset was collected in tropical Atlantic coastal zone of northeastern Brazil where the weather radar was installed. The number of drop was mainly recorded in 300 - 500 drop $mm^{-3}$, of which the maximum was registered around 1.1 mm drop diameter.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.4
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• pp.695-704
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• 2018

The rainfall cases were identified by rainfall estimation techniques which were developed by using X - band marine radar. A digital signal converter was used to convert the signal received from the marine radar into digital reflectivity information. The ground clutter signal was removed and the errors caused by beam attenuation and beam volume changes were corrected. The reflectivity showed a linear relationship with the rain gauge rainfall. Quantitative rainfall was estimated by converting the radar signal into an cartesian coordinate system. When the rainfall was recorded more than $5mm\;hr^{-1}$ at three automatic weather stations, the rain cell distribution on the marine radar was consistent with that of the weather radar operated by Korea meteorological Adminstration.