• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5417-5422
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• 2013

This research was performed in order to improve the goodness of fit of paddy rice production forecasting using MODIS images and to find out appropriate explanatory variables in the forecasting model. The aim of this paper is to review the use of satellite images for the survey of paddy rice production in Korea. Many developed countries, including the United States, Australia, and Japan, have been using satellite images to produce agricultural statistics such as crop production, cultivated acreage, etc. The survey accuracy of crop production by using satellite images, however, is not satisfied in practical use. In this paper, we reviewed several methods to increase the survey accuracy of rice production statistics, gained from satellite images. Rice was selected for this study because its cultivated area and production amount could be more easily identified than other crops by using satellite images. The MODIS images were used because they involved more appropriate images to estimate and analyze rice production. This study estimated yield functions by using the NDVIs, gained from paddy rice yields and annual average isothermal lines, and the meteorological variables such as sunshine hours, rainfall, and temperature during ripening stage. As a result of yield function estimation, the goodness of fit(R-squared) for the models was shown from 0.768 to 0.891. In this study, it is noteworthy academically and practically that vegetation index(NDVIs) identified by annual average isothermal lines and meteorological variables are very useful for estimating yield functions.

• Atmosphere
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• v.15 no.1
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• pp.47-57
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• 2005

Extending the success of the Tropical Rainfall Measuring Mission (TRMM), the spaceborne measurement of precipitation by Global Precipitation Measurement (GPM) is initiated. The GPM consists of a core satellite which will have a dual-frequency precipitation radar (DPR) and a constellation of small satellites equipped with microwave radiometers. The GPM is inherently a global program. Responding to the GPM plan, many other nations are much interested in participating in the GPM team or simply utilizing GPM products aiming at the development of meteorological technology. Korea can fully function its role if Korea is selected as a CAL/VAL site for the GPM because Korea maintains a well-established dense rain gauge network (AWS), precipitation radars, and the Haenam super site for surface observation. In this feasibility study, the necessities of the GPM project in the context of academical and social backgrounds and associated international and domestic activities are investigated. And GPM-related core technologies and application areas are defined. As a result, it is found that GPM will represent a great opportunity for us because of its ability to provide not only much enhanced three-hourly global rain products but also very useful tools for the enhancement of weather forecasting capabilities, management of water resources, development and implementation of monitoring techniques for severe weather phenomena, agricultural managements and climate application. Furthermore, rain retrieval and CAL/VAL technologies obtained during the involvement in the international GPM project will serve as basic knowledges to run our own geostationary satellite program.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1183-1192
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• 2020

Economic analysis is a basic step in establishing disaster mitigation measures, but it is difficult to verify the results due to uncertainty. Therefore, the scope of investigation and analysis is wide. However, it is difficult to predict the amount of damage caused by flooding because the collection of relevant data is limited in the ungauged basin. In this study, distributed runoff analysis and flooding analysis were performed, and a method of estimating the amount of flood damage in the ungauged basin was proposed using collectible social and economic indicators and flood analysis results. For distributed runoff analysis and flooding analysis, GRM (Grid based Rainfall-runoff Model) and G2D (Grid based 2-Dimensional land surface flood model) developed by Korea Institute of Civil engineering and Building Technology were used. The method of substituting collectible social and economic indicators into the simple method and improvement method was used to estimate the amount of flood damage. As a result of the study, it was possible to estimate the amount of flood damage using satellite data and social and economic indicators in the ungauged basin.

• Journal of Korean Elementary Science Education
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• v.17 no.2
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• pp.123-136
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• 1998

In this study, it was purposed to investigate that the student's understading and usage of weather information for the students of elementary, middle and high school The questionaire of 20 questions of 5 categories which included how to get weather information, the understanding of reason for variation of weather elements, the abilities of reading weather map, understanding of weather forecast and the necessity and usefulness of weather map and clouds pictures of weather satellite were prepared and 2 classes of elementary school 5th grade each one class of 2nd and 3rd grade of middle school and 2 classes of high school were tested. followings were revealed in this study; 1) Students of all school are fond of TV watching to get weather information as they used to. 2) They think air temperatures is the most important weather elements and then rainfall. 5ut they seems to unknown the reason why weather elements are vary. 3) They seems to have poor ability of reading weather symbols in weather map and the distribution of air pressure systems. 4) They can read and understand about the reports of words on weather forecast, but most of them can't make weather forecast by the reading of weather map. 5) More than half of students think that the weather map is helpful and especially the cloud pictures from weather satellite is useful for usage of weather information.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.1-10
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• 2017

Sudden natural disasters such as earthquakes, typhoons, heavy rainfall, etc., which come without warning, often threaten our lives and property, so it is important to spread the disaster quickly and accurately. Thus, in this paper, we present a method for the activating of FM radio receiver chip embedded in smartphone to receive disaster broadcasting in case of disaster. One is to investigate the roles and limits in a domestic disaster broadcasting system and disaster relay broadcasting by media, and the other is to present the method for the activation of smartphone FM radio receiver chip by conduct an expert survey.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.6
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• pp.21-33
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• 2007

Different vegetation indices from satellite images have been used for monitoring drought damages, and this study aimed to develop a drought index using NOAA/AVHRR NDVI(Normalized Difference Vegetation Index) and to analyze the temporal and spatial distribution of spring drought severity in North Korea from 1998 to 2001. A new drought index, DevNDVI(Deviation of NDVI), was defined as the difference between a monthly NDVI and average monthly NDVI at the same cover area, and the DevNDVI images at all years except for 2001 demonstrated the drought-damaged areas referred from various domestic and foreign publications. The vegetation of 2001 showed high vitality despite the least amount of rainfall among the target years, and the reason was investigated that higher temperature above normal average would shift the growing stages of plants ahead. Therefore, complementary methods like plant growth models or ground survey data should be adopted in order to evaluate drought-induced plant stress using satellite-based NDVI and to make up far the distortion induced by other environments than lack of precipitation.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.115-124
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• 2010

Urban watershed can be found in the visible changes in technology, the most realistic satellite images is to use the data. Satellite image data on the indicators for progress on the nature of the change of land use is consistent and repetitive information, regular observation makes possible the detailed analysis of space-time. These remote sensing techniques and the type of course and, by using the time series history, the past, the dynamic model and the randomized prediction methodology for the conversion process if the city and river basin cooperation of the space changes effectively will be able to extrapolate. For each of the main changes in river flow, depending on the area of urbanization as determined according to reproduce the duration of the relationship between the urbanization of the area and runoff can be represented as a linear polynomial expression was, if a linear expression in the two fast slew rate of 0.858 to 0.861 showed up, and fast slew rate of 0.934 to 0.974 for the polynomial are reported. Change of land use changes in the watershed of the flow is one of the most affecting elements. Therefore, changes in land use of the correct classification of rivers is a more accurate calculation of the amount of the floodgate. In particular, using the Landsat images through the image of the land use category, land use past data and calculated using the Markov Chain model and predict the future land use plan in the water control project will be used for large likely.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.467-467
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• 2015

Sustainable water resource management requires the assessment of hydrological variability in response to climate fluctuations and anthropogenic activities. Determining quantitative estimates of water balance and total basin discharge are of utmost importance to understand the variations within a basin. Hard-to-reach areas with few infrastructures, coupled with lengthy administrative procedures makes in-situ data collection and water management processes very difficult and unreliable. In this study, the hydrological behavior of Lake Chad whose extent, extreme climatic and environmental conditions make it difficult to collect field observations was examined. During a 10 year period [January 2003 to December 2013], dataset from space-borne and global hydrological models observations were analyzed. Terrestial water storage (TWS) data retrieved from Gravity Recovery and Climate Experiment (GRACE), lake level variations from Satellite altimetry, water fluxes and soil moisture from Global Land Data Assimilation System (GLDAS) were used for this study. Furthermore, we combined altimetry lake volume with TWS over the lake drainage basin to estimate groundwater and soil moisture variations. This will be validated with groundwater estimates from WaterGAP Global Hydrology Model (WGHM) outputs. TWS showed similar variation patterns Lake water level as expected. The TWS in the basin area is governed by the lake's surface water. As expected, rainfall from GLDAS precedes GRACE TWS with a phase lag of about 1 month. Estimates of groundwater and soil moisture content volume changes derived by combining altimetric Lake Volume with TWS over the drainage basin are ongoing. Results obtained shall be compared with WaterGap Hydrology Model (WGHM) groundwater estimate outputs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.915-922
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• 2008

Impervious surface is an important index for the estimation of urbanization and the assessment of environmental change. In addition, impervious surface influences on short-term rainfall-runoff model during rainy season in hydrology. Recently, the necessity of impervious surface estimation is increased because the effect of impervious surface is increased by rapid urbanization. In this study, impervious surface estimation is performed by using remote sensing image such as Landsat-7 ETM+image with $30m{\times}30m$ spatial resolution and satellite image with $1m{\times}1m$ spatial resolution based on Jungnangcheon basin. A tasseled cap transformation and NDVI(normalized difference vegetation index) transformation are applied to Landsat-7 ETM+ image to collect various predict variables. Moreover, the training data sets are collected by overlaying between Landsat-7 ETM+ image and satellite image, and CART(classification and regression tree) is applied to the training data sets. As a result, impervious surface prediction model is consisted and the impervious surface map is generated for Jungnangcheon basin.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.683-693
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• 2023

In this study, we used satellite images to analyze the green algae phenomenon that first occurred in Soyang-ho, which was completed in 1973. The research data used 13 optical images over a period of about 2 months from July 2023, and the area of green algae that occurred in Soyang-ho was calculated. To calculate the exact area where green algae occurred, image classification was performed based on the support vector machine algorithm. As a result, green algae in Soyang-ho occurred around the point where the impurities that caused the green algae were introduced. It seemed to temporarily decrease due to the effects of Typhoon Khanun in August 2023, but green algae increased again due to the continued heat. Soyang-ho is one of the major water sources in the metropolitan area, suggesting that we must prepare for repeated green algae outbreaks.