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The extraction method of surface temperature in agricultural area using Satellite Remote Sensing and GIS Spatial meteorological analysis of Ansung watershed area
 Fig. 10 Multi-temporal landcover classification map 
Fig. 11 Multi-temporal surface temperature distribution map As a result of landcover classification in the area, forest was distributed to the most of there and it showed following the order such as paddy field, field, urban, barren, and stream. In result of the <Figure 10>, it is showed that both forest and paddy field were decreased generally, while both urban and field were increased especially in centering around Ipjang-Myeon where was much increased to field. This was to be analyzed with the result indicated by the increase of the cultivation grape from 1990 when was active. Both Ansung-eup and Cheonan-city area were showed in raising the most active in tie studied area, developing the streets of the city along most roads, classifying many urban area centered by the location of Myeon or Eup. On the other hand the classified barren was to be identified with wasting land mostly to develop either of the golf or crop field. In 2000 the forest, paddy field, and field were decreased and otherwise the stream as well as the barren was increased. While the average surface temperature in the basin of Ansung-watershed area extracted from multi-temporal Landsat TM band 6 presented both 21.68℃ in 1987 and 23.16℃ in 1993, the result which was classified again to 7 classes of it is the same that < Figure 11>. As a result of comparing the temperature between '87 and '93 in these of them, the forest and stream showed the lowest temperature distribution, as well as the pattern of the surface temperature distribution ordering field > paddy field> forest > stream, the location of Myeon and Eup showed the highest temperature distribution. In addition, this study analyzed the change pattern of surface temperature in the basin of Ansung stream by the change of landcover such as the < Figure 12>, obtaining the value of surface temperature by multi-temporal, selecting the training area to each class with the standard landcover classification of (Figure 10). 
Fig. 12 The change of surface temperature on the change of landcover It could be identified the temperature increase from the minimum 0.9℃ to the maximum 2.15℃ according to decrease of forest, paddy field, field and stream area. While the temperature of urban and barren were increased from 0.03 to 1.83℃ because the sizes of area were increased. To look over the temperature change by landcover classes concretely about them, the surface temperature was increased to 1.55℃ while the forest was decreased as '93 compared with '87. As the paddy field was decreased to 19.1 It could be analyzed the change pattern of the temperature environment of the agricultural area by the urbanization based on the both the increasing and decreasing phenomenon in the surface temperature according to landcover change in the basin of Ansung stream. As a result analyzing the area, aspect, slope, temperature, and NDVI according to elevation in the basin of Ansung-stream, the highest value of the area is represented between 0 and 50m level, and it could be identified that the more elevation, the lower proportion of area is. Collectively aspect inclines toward the south, 351∼400m level and 501∼570 level is under 10° and the rest of sections is over 10°which has the steep gradient. The average temperature shows descending trends according to raising the elevation, and NDVI shows ascending trends according to raising the value. In 1987 28℃∼31℃ which is the highest surface temperature class distributes that the average elevation is 35.22m topographically and the slope distributes 1.31°. It cloud be found that as the temperature shows the high value, slope, elevation, and average value of NDVI are descended. This is analyzed as the result because the level of the high temperature is generally formed in the flat area where is centered except some of vegetation area in city. It could be identified that the NDVI, elevation, slope has the consistent correlation according to the temperature. 
Fig. 13 Distribution map of NDVI The higher NDVI value, the higher elevation and slope value is. It is showed that the proportional relation, as the result in the correlation analysis, the lower NDVI value, the higher temperature is. It could be identified that analyzing the result of the produced value of the vegetation index by using the Landsat TM band 3, band4. The golf area and industrial complex when was increased in 1993 in comparison with 1987 changed the vegetation index of some area. With the basis of this result this study implemented both the correlation and regression analysis to examine the correlation between surface temperature and NDVI. The result is in 
Fig. 14. Regression analysis between NDVI and surface temperature The spatial analysis of watershed property factor The drainage density, drainage frequency, and catchment concentration rate and bifurcation were calculated on the basis of the catchment area, perimeter an stream length in the basin of Ansung stream using GIS TOOL. As a result, catchment area 585.18 stream length 569.60 the perimeter 137.5, drainage density 0.97, the total numbers of streams 854.00, drainage frequency 1.45, catchment concentration 7.31 were produce. As a consequence of surface temperature to each area, Gumkwang-Myeon, which is high drainage density to basin is 20.5℃, Gongdo-Myeon, which is low, is 23.6℃ As an influential factor, which affects landcover change and surface temperature, as a result of investigating population distribution around basin 1995 to 2000, such as in Ansung-city, Asan-city, Cheonan-city the population has been increasing continually. These regions indicate that the temperature is rising according to urbanization, forming housing, roads, commercial and industrial zones. On the other hand, in proportion to the decrease of population, the temperature has been low. The temperature is changed by population distribution for each area. 
Fig. 15 The temperature change of each area on population distribution As a result of extracting topographical information each administrative regions, in high temperature area around Ansung-watershed area, the regions such as Ansung-city, Cheonahn-city, which are characteristic of urbanization, are showed the high surface temperature. And also compare to distribution the average elevation, 79.08m, that of this area is low in 35.61m, for the average slope 6.26˚, the average of this area is 2.26˚. The higher the temperature, the lower NDVI value is, the larger population, the higher temperature is. As a result of analyzing the characteristic of surface temperature distribution to topographical feature nearby river, the surface temperature is high in Ansung-city and Daedeok-Myeon, average latitude height 20∼40m, slope less than 2˚, area mainly faced on South-Western aspects high surface temperature zone more than 9℃ was identified. The analysis of landcover environment showing high surface temperature zone indicates urban area and industrial complex of suburbs. 
Fig. 16 High temperature distribution map surrounding Ansung-watershed area |