• Title/Summary/Keyword: desert

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Development of Stochastic Model and Simulation for Spatial Process Using Remotely Sensed Data : Fire Arrival Process (원격탐사자료를 이용한 공간적 현상의 모형화 및 시뮬레이션 : 자연화재발생의 경우)

  • 정명희
    • Spatial Information Research
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    • v.6 no.1
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    • pp.77-90
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    • 1998
  • The complex interactions of climate, topography, geology, biota and hwnan activities result in the land cover patterns, which are impacted by natural disturbances such as fire, earthquake and flood. Natural disturbances disrupt ecosystem communities and change the physical environment, thereby generating a new landscape. Community ecologists believe that disturbance is critical in determining how diverse ecological systems function. Fires were once a major agent of disturbance in the North American tall grass prairies, African savannas, and Australian bush. The major focus of this research was to develop stochastic model of spatial process of disturbance or spatial events and simulate the process based on the developed model and it was applied to the fire arrival process in the Great Victoria Desert of Australia, where wildfires generate a mosaic of patches of habitat at various stages of post-fire succession. For this research, Landsat Multi-Spectral Scanner(MSS) data covering the period from 1972 to 1994 were utilized. Fire arrival process is characterized as a spatial point pattern irregularly distributed within a region of space. Here, nonhomogeneous planar Poisson process is proposed as a model for the fire arrival process and rejection sampling thinning the homogeneous Poisson process is used for its simulation.

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Accuracy Comparison Of Ground Control Points extracting from LIDAR Intensity (라이다의 반사강도에서 추출한 지상기준점의 정확도 비교)

  • Wie, Gwang-Jae;Choi, Yun-Soo;Oh, Jong-Min;Lee, Im-Pyung;Suh, Young-Woon
    • Journal of Korean Society for Geospatial Information Science
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    • v.16 no.4
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    • pp.25-31
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    • 2008
  • As we choose ground control points for aerial triangulation, we have a lot of problems in a mountain, a costal area, a desert, the foreshore etc because they don't have clear topography for control points and it spends a lot of cost and occurs problems of accuracy. In this study, we compare and analyze between ground control points from LiDAR intensity, digital map with ground control points from the field survey as doing AT each. As the result, the average error was ${\pm}1.02m$ from using LiDAR intensity, ${\pm}1.13m$ from using digital map. this result can present the control points from LiDAR intensity is 0.11m better than from digital map.

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Study on Performance Improvement Air Cooled Condenser Considering Ambient Condition (대기 조건에 따른 공랭식 응축기 성능 저하 개선 연구)

  • Cha, Hun;Ryu, Gwang-Nyeon;Kim, Jung-Rae
    • Transactions of the KSME C: Technology and Education
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    • v.3 no.3
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    • pp.201-207
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    • 2015
  • Air cooled condenser for power plant is used at inland area of desert or mountainous area because condenser coolant like sea water is not necessary. However, the performance of air cooled condenser is influenced by ambient condition such as wind speed and air temperature. Therefore, various devices have been designed to improve the performance of air cooled condenser. In this study, the CFD analysis for air cooled condenser was carried out according to wind speed and wind screen configuration. As wind speed increased from 3m/s to 7m/s, the fan flow rate was reduced about 15.76% and the rise of inlet air temperature was 5.55 degree of Celsius. When the suitable wind screen is equipped, the fan flow rate went up about 5.18% and inlet air temperature dropped by 2.08 degree of Celsius in comparison with original case without wind screen at 7m/s wind speed.

Fodder Supply in Cold Season in Gobi Nomadic Area, Mongolia

  • Yamasaki, S.;Ishida, J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.2
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    • pp.203-206
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    • 2004
  • Fodder supply condition was studied at 41 nomadic families in Gobi, Southern Semi-Desert area in Mongolia, from Dec. 1994 to Apr. 1995 to determine problems in cold, feed deficient season for establishment of sustainable livestock production system. The conditions of two family groups: those located in sparse vegetation (FG1), and those in comparably dense (FG2), were also compared. Commercial concentrate feed (concentrate), hay and Zoodoi were prepared for supplementation. Zoodoi was hand-made feed made mainly of Allium mongolicum and Allium polyrrhizum. Allium mongolicum tended to be used at FG1 frequently, and Allium polyrrhizum at FG2 depend on differences of micro vegetation. 44%, 90% and 39% of families prepared 165.6 kg of concentrate, 301.6 kg of hay and 6.8 kg of Zoodoi per sheep and goat (small livestock) on the average, respectively. The ratio of families that used concentrate at FG1 was smaller than those at FG2, though there were no significant differences on the amount. More hay was fed at FG1 than at FG2, and Zoodoi tended to be fed more in the FG1 group. Recipients were mostly restricted to young, female and sick small livestock that use the feeds effectively. More families gave concentrate and hay to the young than to the females and sick. They also gave more Zoodoi to young and sick animals than to females in this area. In the FG1 group, no differences were found between recipients on the concentrate supply. More families supplied hay to young animals than to sick ones, and Zoodoi was fed more to sick animals than to young and females. On the other hand, those in the FG2 found, more families fed fodders to young than to female and sick regardless of the kinds of feeds. The amount of fodder supplementation in the studied area was restricted, but accurate techniques of nomads to adapt the situation were clarified.

Study on the Morphological Parameters and Evolution of Caragana microphylla Lam. Nebkhas in Inner Mongolia, China

  • Na, Yan;Eerdun, Hasi;Park, Ki-Hyung;Xia, Xian-Dong;Chun, Kun-Woo
    • Journal of Korean Society of Forest Science
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    • v.98 no.2
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    • pp.156-162
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    • 2009
  • Nebkhas are widely distributed in farming-pastoral zones, typical grassland and desert margins. In the southeast of the Inner Mongolia Plateau, it is mainly distributed at the leeward of cultivated land and alluvial fan, severe deterioration rangeland and around residential points. Through the field measurement and statistical analysis of Caragana microphylla Lam. Nebkhas morphological parameters (length, width and height of Nebkhas are included), the results show that there were close correlations between the Nebkhas morphological parameters. The ranges of height and width of Nebkhas changed dramatically and have reached up to 11.44 m and 7.97 m respectively, however, the change range of height was relatively smaller and just 1.09 m. The morphological parameters change of the same type Nebkhas in the same region was large ranging from 0.56 m in height, 3.56 m in width to 6.96 m in length, while the morphological characteristics of the same type Nebkhas in different regions were much similar. A correlation between length and width was significantly positive, but the correlations between height and length, and between height and width were much more complicated. It can be concluded that the Nebkhas in Zhengxiangbai Banner and Taipusi Banner were at the initially growing stage, while the Nebkhas in Huade County belonged to a transitional stage from the growing phase to the stabilizing phase. The changing regularity of distance between Nebkhas in along-wind direction was not consistent.

PHYSIOLOGICAL RESPONSES OF GROWING RAMS TO ASBESTOS SHADING DURING SUMMER

  • Tharwat, E.E.;Amin, S.O.;Younis, A.A.;Kotby, E.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.4 no.4
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    • pp.395-398
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    • 1991
  • Physiological reactions of 24 six months old (22.7 kg. body weight) Barki ram lambs, to hot summer conditions, as influenced by asbestos shading at Maryout area were studied. Animals (12 shaded and 12 Unshaded) developed hyperthermia during summer as their rectal temperature (RT) and respiration rate (RR) were always higher (p<0.01) than normal. Asbestos shading caused higher (p<0.05) RT and RR ($39.5^{\circ}C$ and 69.9 r.p.m. vs. 39.2 and 45.7 r.p.m.) of rams at morning (6-8 a.m.) which became lower ($39.9^{\circ}C$ and 104.3 r.p.m. vs. $40.1^{\circ}C$ and 120.5 r.p.m.) in afternoon (2-4 p.m.) as compared to sun exposure. Shading also resulted in higher hematocrit value (PCV) (35.3% vs. 33.0%) and lower (p<0.05) daily weight gain (128.57 vs. 131.43 g). Diurnal (p<0.01) and monthly (p<0.05) RT and RR changes were closely associated with air temperature (AT) fluctuations. Monthly variation (p<0.05) in PCV was evident. Puberty was reached one month later in the shaded as compared to the unshaded group (265 vs. 232.3 day, respectively). It is concluded that asbestos shading prevents efficient heat dissipation to the sky by hyperthermic rams during summer nights. Construction materials for animal shelters are of extreme practical importance.

Comparative Studies on Growth and Phosphatase Activity of Endolithic Cyanobacterial Isolates of Chroococcidiopsis from Hot and Cold Deserts

  • BANERJEE, MEENAKSHI;DEBKUMARI, SHARMA
    • Journal of Microbiology and Biotechnology
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    • v.15 no.1
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    • pp.125-130
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    • 2005
  • The growth and phosphatase (phosphomonoesterase) activity of Chroococcidiopsis culture isolated from the cryptoendoliths of the Antarctic were compared with a similar isolate from the Arizona hot desert. Such cyanobacteria living inside rocks share several features with the immobilized cells produced in the laboratory. This study has relevance because the availability of phosphorus is a key factor influencing the growth of these cyanobacteria in nature, in such unique ecological niches as the hot and cold deserts. Phosphatase activity therefore is of particular importance for these organisms if they are to survive without any other source of phosphorus availability. Also, there is paucity of knowledge regarding this aspect of study in cyanobacterial cultures from these extreme environments. The salient feature of this study shows the importance of specific pH and temperatures for growth and phosphatase activity of both cultures, although there were marked differences between the two isolates. The pH and temperature optima for growth and phosphatase activity (PMEase) of Chroococcidiopsis 1 and 2 were 9.5, $240^{\circ}C$ and 8.5, $40^{\circ}C$ respectively. The $K_m and V_max$ values of cultured Chroococcidiopsis 1 showed lower affinity of PMEase for the substrate compared to the enzyme affinity of the same organism when found within the rocks; Chroococcidiopsis 2 and Arizona rocks containing the same alga however showed similar affinity of PMEase for the substrate. An interesting observation was the similarity in response of immobilized Chroococcidiopsis 1 culture and the same organism in the Antarctic rocks to low light and low temperature stimulation of PMEase. This thermal response seems to be related to the ability of the immobilized Antarctic isolate and the rocks to either cryoprotect the PMEase or undergo a change to save the enzyme from becoming nonfunctional under low temperatures. The free cells of Chroococcidiopsis 1 culture however did not show such responses.

The Effect of Dust Emissions on PM10 Concentration in East Asia (황사 배출량이 동아시아 지역 PM10 농도에 미치는 영향)

  • Choi, Dae-Ryun;Koo, Youn-Seo;Jo, Jin-Sik;Jang, Young-Kee;Lee, Jae-Bum;Park, Hyun-Ju
    • Journal of Korean Society for Atmospheric Environment
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    • v.32 no.1
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    • pp.32-45
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    • 2016
  • The anthropogenic aerosols originated from the pollutant emissions in the eastern part of China and dust emitted in northwestern China in Yellow sand regions are subsequently transported via eastward wind to the Korean peninsula and then these aerosols induce high $PM_{10}$ concentrations in Korean peninsula. In order to estimate air quality considering anthropogenic and dust emissions, Comprehensive Air-quality Model with extension (CAMx) was applied to simulate $PM_{10}$ concentration. The predicted $PM_{10}$ concentrations without/with dust emissions were compared with observations at ambient air quality monitoring sites in China and Korea for 2008. The predicted $PM_{10}$ concentrations with dust emissions could depict the variation of measured $PM_{10}$ especially during Yellow sand events in Korea. The comparisons also showed that predicted $PM_{10}$ concentrations without dust emissions were under-predicted while predictions of $PM_{10}$ concentrations with dust emission were in good agreement with observations. This implied that dust emissions from desert and barren soil in southern Mongolia and northern China minimized the discrepancies in the $PM_{10}$ predictions in East Asia. The effect of dust emission on annual $PM_{10}$ concentrations in Korea Peninsula for year 2008 was $5{\sim}10{\mu}g/m^3$, which were about 20% of observed annual $PM_{10}$ concentrations.

The Study on the Quantitative Dust Index Using Geostationary Satellite (정지기상위성 자료를 이용한 정량적 황사지수 개발 연구)

  • Kim, Mee-Ja;Kim, Yoonjae;Sohn, Eun-Ha;Kim, Kum-Lan;Ahn, Myung-Hwan
    • Atmosphere
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    • v.18 no.4
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    • pp.267-277
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    • 2008
  • The occurrence and strength of the Asian Dust over the Korea Peninsular have been increased by the expansion of the desert area. For the continuous monitoring of the Asian Dust event, the geostationary satellites provide useful information by detecting the outbreak of the event as well as the long-range transportation of dust. The Infrared Optical Depth Index (IODI) derived from the MTSAT-1R data, indicating a quantitative index of the dust intensity, has been produced in real-time at Korea Meteorological Administration (KMA) since spring of 2007 for the forecast of Asian dust. The data processing algorithm for IODI consists of mainly two steps. The first step is to detect dust area by using brightness temperature difference between two thermal window channels which are influenced with different extinction coefficients by dust. Here we use dynamic threshold values based on the change of surface temperature. In the second step, the IODI is calculated using the ratio between current IR1 brightness temperature and the maximum brightness temperature of the last 10 days which we assume the clear sky. Validation with AOD retrieved from MODIS shows a good agreement over the ocean. Comparison of IODI with the ground based PM10 observation network in Korea shows distinct characteristics depending on the altitude of dust layer estimated from the Lidar data. In the case that the altitude of dust layer is relatively high, the intensity of IODI is larger than that of PM10. On the other hand, when the altitude of dust layer is lower, IODI seems to be relatively small comparing with PM10 measurement.

Effects of Asian Dust on Fruiting and Fruit Quality in Korean Fruit Trees Based on Artificial Spray Experiments Using Loess from the Source Region (황사 발원지 황토를 이용한 인공 황사 살포처리가 과수의 착과와 과실품질에 미치는 영향)

  • Seo Hyeong-Ho;Kim Jeom-Kuk;Park Moo-Yong;Kim Seung-Heui;Do Kyung-Ran
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.3
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    • pp.169-173
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    • 2006
  • This study used loess from the source region of Asian dust (a desert area in China) to analyze the effects of Asian dust on fruiting and fruit quality in Korean fruit trees. Asian dust and loess from the source region were highly alkaline compared to average Korean field soil. Organic material contents of Asian dust were about three times as high as that of the average field soil. Loess was dusted onto the stigma of apple, pear, and peach trees. fruiting, seed number, fruit quality and pollen tube elongation were investigated. Pollination and fertilization were not influenced while pollen tube elongation was slightly influenced. Consequently, fruiting, seed number and fruit quality were not affected by the dusting treatment.