• Title/Summary/Keyword: SSM/I

Search Result 38, Processing Time 0.026 seconds

Comparative Study of KOMPSAT-1 EOC Images and SSM/I NASA Team Sea Ice Concentration of the Arctic (북극의 KOMPSAT-1 EOC 영상과 SSM/I NASA Team 해빙 면적비의 비교 연구)

  • Han, Hyang-Sun;Lee, Hoon-Yol
    • Korean Journal of Remote Sensing
    • /
    • v.23 no.6
    • /
    • pp.507-520
    • /
    • 2007
  • Satellite passive microwave(PM) sensors have been observing polar sea ice concentration(SIC), ice temperature, and snow depth since 1970s. Among them SIC is playing an important role in the various studies as it is considered the first factor for the monitoring of global climate and environment changes. Verification and correction of PM SIC is essential for this purpose. In this study, we calculated SIC from KOMPSAT-1 EOC images obtained from Arctic sea ice edges from July to August 2005 and compared with SSM/I SIC calculated from NASA Team(NT) algorithm. When we have no consideration of sea ice types, EOC and SSM/I NT SIC showed low correlation coefficient of 0.574. This is because there are differences in spatial resolution and observing time between two sensors, and the temporal and spatial variation of sea ice was high in summer Arctic ice edge. For the verification of SSM/I NT SIC according to sea ice types, we divided sea ice into land-fast ice, pack ice, and drift ice from EOC images, and compared them with SSM/I NT SIC corresponding to each ice type. The concentration of land-fast ice between EOC and SSM/I SIC were calculated very similarly to each other with the mean difference of 0.38%. This is because the temporal and spatial variation of land-fast ice is small, and the snow condition on the ice surface is relatively dry. In case of pack ice, there were lots of ice ridge and new ice that are known to be underestimated by NT algorithm. SSM/I NT SIC were lower than EOC SIC by 19.63% in average. In drift ice, SSM/I NT SIC showed 20.17% higher than EOC SIC in average. The sea ice with high concentration could be included inside the wide IFOV of SSM/I because the drift ice was located near the edge of pack ice. It is also suggested that SSM/I NT SIC overestimated the drift ice covered by wet snow.

Comparison of SSM/I Sea Ice Concentration with Kompsat-1 EOC Images of the Arctic and Antarctic (북극과 남극의 SSM/I Sea Ice Concentration과 Kompsat-1 EOC 영상의 비교)

  • Han Hyang-Sun;Lee Hoon-Yol
    • Proceedings of the KSRS Conference
    • /
    • 2006.03a
    • /
    • pp.153-156
    • /
    • 2006
  • 북극과 남극의 해빙을 촬영한 Kompsat-1 EOC 영상을 SSM/I Sea Ice Concentration(SIC)과 비교하였다. EOC 영상은 2005년 $7{\sim}8$월 북극 해빙지역의 가장자리를 지나는 10개 궤도(624 영상)와 $9{\sim}11$월 남극대륙의 가장자리를 지나는 11개 궤도(676 영상)에서 얻어졌다. 그 중 구름의 영향이 없는 약 12%의 영상으로부터 감독분류와 육안분류를 통해 Multi-year ice와 First-year ice(M+F), Young ice(Y), New ice(N)로 해빙의 유형을 구분하여 SIC를 계산하였으며, 이를 NASA Team Algorithm(NTA)으로 계산된 SSM/I SIC와 비교하였다. 북극의 여름철에는 해빙의 시공간적 변화가 매우 크기 때문에 EOC SIC(M+F+Y+N)와 SSM/I SIC의 상관계수는 0.671로 잘 일치하지 않았다. 남극의 봄철에 N을 제외한 EOC SIC(M+F+Y)의 경우 SSM/I SIC와 0.873의 높은 상관계수를 가졌다. 이로부터 NTA로 계산된 남극의 SSM/I SIC가 M과 F를 비롯하여 Y도 포함하는 것을 알 수 있었다.

  • PDF

Comparative Analysis of SSM/I and AMSR-E Sea Ice Concentration using Kompsat-l EOC Images of the Antarctic (Kompsat-l EOC 영상을 이용한 남극의 SSM/I 와 AMSR-E 해빙 면적비 비교 분석)

  • Han, Hyang-Sun;Lee, Hoon-Yol
    • Proceedings of the KSRS Conference
    • /
    • 2007.03a
    • /
    • pp.8-13
    • /
    • 2007
  • 2005년 남극의 해빙을 촬영한 Kompsat-1 EOC 영상을 이용하여 SSM/I와 AMSR-E 해빙 면적비를 비교, 분석하였다. EOC 영상은 남극의 봄철에 해당하는 9-11월 사이에 남극 대륙의 가장자리를 가로지르는 11 개 궤도로부터 총 676개 영상이 획득되었으며, 이 중 대기 및 광량 조건이 양호한 68개 의 영상을 선별하였다. EOC 영상에 감독분류 방볍 을 적 용하여 표면 유형 을 White ice(W), Grey ice(G), Dark-grey ice(D), Ocean(O)로 분류하였고 해빙 면적비를 산출하였으며, 이를 NASA Team Algorithm(NT)으로 계산된 SSM/I 해빙 면적비, NASA Team2 Algorithm(NT2)으로 계산된 AMSR-E 해빙 면적비와 비교하였다. 남극의 봄철에 SSM/I 해빙 면적비는 EOC W+G 면적비와 잘 일치하였고,AMSR-E 해빙 면적비는 EOC W+G+D 면적비와 좋은 상관성을 나타내었다. 따라서 이 시기의 남극 SSM/I NT 해빙 면적비는 W와 G만을 반영하며, AMSR-E NT2 해빙 면적비는 D도 포함하는 것을 알 수 있었다. 또한 AMSR-E가 SSM/I보다 높은 해빙 면적비를 나타내는 것을 확인하였으며,두 수동 마이크로파 해빙 면적비의 차이는 EOC D 면적비와 높은 상관성을 보였다. 이로부터 EOC 영상에서 분류된 D와 NT2에 서 고려되는 Ice type C가 서로 유사한 해빙 유형임을 추정할 수 있었다.

  • PDF

Estimation of Cloud Liquid Watetr used by GMS-5 Observations (GMS-5 자료를 이용한 구름 수액량 추정 연구)

  • 차주완;윤홍주
    • Korean Journal of Remote Sensing
    • /
    • v.15 no.1
    • /
    • pp.21-30
    • /
    • 1999
  • The CLW (Cloud Liquid Water) is a parameter of vital interest in both modeling and forecasting weather. In mesoscale models, the magnitude of latent heat effects corresponds to the amount of CLW, which is important in the development of a certain weather system. The goal of this study is the estimation of CLW by GMS-5 data which is compared with that of SSM/I data and GMR(Grounded Microwave Radiometer)data. First of all, we found out the relationship of cloud albedo to cloud thickness, and caculated the CLW using the result of the relationship. The CLW amount of SSM/I or GMR and that of GMS-5 were compared, respectively. The correlation coefficient was about 0.86 and RMSE was 9.23 mg/$cm^2$ between GMS-5 data and GMR data. And also the correlation coefficient was 0.84 and RMSE was 14.02 mg/$cm^2$ between GMS-5 data and SSM/I data.

The Impact of SSM Market Entry on Changes in Market Shares among Retailing Types (기업형 슈퍼마켓(SSM)의 시장진입이 소매업태간 시장점유율 변화에 미친 영향)

  • Choi, Ji-Ho;Yonn, Min-Suk;Moon, Youn-Hee;Choi, Sung-Ho
    • Journal of Distribution Research
    • /
    • v.17 no.3
    • /
    • pp.115-132
    • /
    • 2012
  • This study empirically examines the impact of SSM market entry on changes in market shares among retailing types. The data is monthly time-series data spanning over the period from January 2000 to December 2010, and the effect of SSM market entry on market shares of retailing types is analyzed by utilizing several key factors such as the number of new SSM monthly entrants, total number of SSMs, the proportion of new SSM entrant that is smaller than $165m^2$ to total new SSM entrants. According to the Korean Standard Industrial Classification codes, the retailing type is classified into 5 groups: department stores, retail sale in other non-specialized large stores(big marts), supermarkets, convenience stores, and retail sale in other non-specialized stores with food or beverages predominating (others). The market shares of retailing types are calculated by the ratio of each retailing type monthly sales to total monthly retailing sales in which total retailing sales is the sum of each retailing type sales. The empirical model controls for the size effects with the number of monthly employees for each retailing type and the macroeconomic effects with M2. The empirical model employed in this study is as follows; $$MS_i=f(NewSSM,\;CumSSM,\;employ_i,\;under165,\;M2)$$ where $MS_i$ is the market share of each retailing type (department stores, big marts), supermarkets, convenience stores, and others), NewSSM is the number of new SSM monthly entrants, CumSSM is total number of SSMs, $employ_i$ is the number of monthly employees for each retailing type, and under165 is the proportion of new SSM entrant that is smaller than $165m^2$ to total new SSM entrants. The correlation among these variables are reported in

    .
    shows the descriptive statistics of the sample. Sales is the total monthly revenue of each retailing type, employees is total number of monthly employees for each retailing type, area is total floor space of each retail type($m^2$), number of store is total number of monthly stores for each retailing type, market share is the ratio of each retailing type monthly sales to total monthly retailing sales in which total retailing sales is the sum of each retailing type sales, new monthly SSMs is total number of new monthly SSM entrants, and M2 is a money supply. The empirical results of the effect of new SSM market entry on changes in market shares among retailing types (department stores, retail sale in other non-specialized large stores, supermarkets, convenience stores, and retail sale in other non-specialized stores with food or beverages predominating) are reported in
    . The dependant variables are the market share of department stores, the market share of big marts, the market share of supermarkets, the market share of convenience stores, and the market share of others. The result shows that the impact of new SSM market entry on changes in market share of retail sale in other non-specialized large stores (big marts) is statistically significant. Total number of monthly SSM stores has a significant effect on market share, but the magnitude and sign of effect is different among retailing types. The increase in the number of SSM stores has a negative effect on the market share of retail sale in other non-specialized large stores(big marts) and convenience stores, but has a positive impact on the market share of department stores, supermarkets, and retail sale in other non-specialized stores with food or beverages predominating (others). This study offers the theoretical and practical implication to these findings and also suggests the direction for the further analysis.

  • PDF
  • Characteristics of 1994-95 Summer Monsoon Inferred from SSM/I-derived Water Budget Parameters (SSM/I 대기물수지 변수를 이용한 1994-95년 하계 몬순의 특성 연구)

    • 손병주;김도형;김혜영;서애숙
      • Korean Journal of Remote Sensing
      • /
      • v.14 no.1
      • /
      • pp.1-16
      • /
      • 1998
    • Microwave brightness temperature data measured from the Special Sensor Microwave/Imager (SSM/I) aboard Defense Meteorological Satellite Program (DMSP) satellite are used to investigate the characteristics of hydrological features of the East Asian summer monsoon during 1994 and 1995. The analyzed parameters include total columnar water vapor, cloud liquid water, and rain rate. These are estimated from SSM/I brightness temperature data for the two summer seasons (June, July, August) of 1994 and 1995 over the Asian monsoon region (0$^{\circ}$-60$^{\circ}$N, 45$^{\circ}$-180$^{\circ}$E). Results indicate that there are periodic westward movement of dry air over the 20$^{\circ}$-30$^{\circ}$N latitudinal belt with about 20-30 day period. Considering that the location of the North Pacific high is closely linked to the evolution of the monsoon activities over East Asia, the westward expansion of the North Pacific high may be the one important element modulating the monsoon intensity.

    Total Precipitable Water Fields of Typhoons WALT(9407) & FAYE(9503) Derived from TOVS and SSM/I (TOVS 자료로 도출한 태풍(WALT(9407)과 FAYE(9503))에 동반된 총가강수량장)

    • 정효상
      • Korean Journal of Remote Sensing
      • /
      • v.14 no.4
      • /
      • pp.315-324
      • /
      • 1998
    • The total precipitable water fields derived from HIRS(High Resolution Infrared Radiometer Sounder)and MSU(Microwave Sounding Unit) measurements of TOVS and brightness temperature of SSM/I were used to investigate the evolution of moisture fields for the Typhoon WALT(9407) which after landing in Japan it became tropical depression in Korea-Japan Strait, and FAYE(9503) which was the first tropical storm of 1995 to became a typhoon, respectively. The total precipitable water derived from TOVS observations is delineated according to the evolutions of WALT and FAYE movements because total precipitable water fields of TY WALT(9407) and FAYE9\(9503) were largely controlled by horizontal transport of water vapor over the Northwest Pacific Ocean which dominantly plays an important role in maintaining and accelerating their intensities toward Korea and Japan . These fields demonstrated that two major bands, which imply the rain bands, were locally well-organized and similar to the thick convective cloud features over Japan and the Korean peninsula while WALT and FAYE were approaching away and to. But the values of derived TOVS total precipitable water have shown the underestimate of those of SSM/I total comparatively for two typhoons.

    Infrared Rainfall Estimates Using the Probability Matching Method Applied to Coincident SSM/I and GMS-5 Data

    • Oh, Hyun-Jong;Sohn, Byung-Ju;Chung, Hyo-Sang
      • Proceedings of the KSRS Conference
      • /
      • 1999.11a
      • /
      • pp.117-121
      • /
      • 1999
    • Relations between GMS-5 infrared brightness temperature with SSM/I retrieved rain rate are determined by a probability matching method similar to Atlas et al. and Crosson et al. For this study, coincident data sets of the GMS-5 infrared measurements and SSM/I data during two summer seasons of 1997 and 1998 are constructed. The cumulative density functions (CDFs) of infrared brightness temperature and rain rate are matched at pairs of two variables which give the same percentile contribution. The method was applied for estimating rain rate on 31 July 1998, examining heavy rainfall estimation of a flash flood event over Mt. Jiri. Results were compared with surface gauge observations run by Korean Meteorological Administration. It was noted that the method produced reasonably good quality of rain estimate, however, there was large area giving false rain due to the anvil type clouds surrounding deep convective clouds. Extensive validation against surface rain observation is currently under investigation.

    • PDF

    Neuroprotective Effects of Stachys sieboldii Miq. Extract Against Ischemia/reperfusion-induced Apoptosis in SH-SY5Y Neuroblastoma Cells (허혈-재관류 유도 신경세포사멸에 대한 초석잠 추출물의 신경보호 효과 연구)

    • Young-Kyung Lee;Chul Hwan Kim;Su Young Shin;Buyng Su Hwang;Min-Jeong Seo;Hye Jin Hwang;Kyung-Min Choi;Jin-Woo Jeong
      • Proceedings of the Plant Resources Society of Korea Conference
      • /
      • 2020.08a
      • /
      • pp.76-76
      • /
      • 2020
    • Stachys sieboldii Miq. (chinese artichoke), which has been extensively used in oriental traditional medicine to treat of ischemic stroke; however, the role of Stachys sieboldii Miq. (SSM) in cerebral ischemia/reperfusion (I/R) injury is not yet fully understood. In the current study, the neuroblastoma cell line (SH-SY5Y) were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) to simulate I/R injury in vitro model. The results showed that SSM improved OGD/R-induced inhibitory effect on cell viability of SH-SY5Y Cells. SSM displayed anti-oxidative activity as proved by the decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and increased activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in OGD/R-induced SH-SY5Y Cells. In addition, cell apoptosis was markedly decreased after SSM treatment in OGD/R-induced SH-SY5Y Cells. The up-regulation of Bcl-2 and down-regulation of Bax, thus reducing the Bax/Bcl-2 ratio that in turn protected the activation of caspase-9 and -3, and inhibition of poly (ADP-ribose) polymerase cleavage, which was associated with the blocking of cytochrome c release to the cytoplasm. Collectively, SSM protected human neuroblastoma SH-SY5Y cells from OGD/R-induced injury via preventing mitochondrial-dependent pathway through scavenging excessive ROS, suggesting that SSM might be a potential agent for the ischemic stroke therapy.

    • PDF

    Reheating Process of Semi-Solid Aluminum Alloy (반융용알루미늄재료의 재가열공정)

    • 강성수;도영진;강충길
      • Proceedings of the Korean Society for Technology of Plasticity Conference
      • /
      • 1997.06a
      • /
      • pp.16-27
      • /
      • 1997
    • A semi-solid forming has a lot of advantages compared to the die casting, squeeze costing and convenctional forging, therefore, semi-solid forming process are now becoming of industial interest for the production of metal components and metal matrix composites. However, the material behaviour in the semi-solid temperature range is not sufficiently known although it controls the whole process through forces and geometry evolutions bcause the behaviour of metal slurries is complex. The semi-solid materials(SSM) fabricated under electric-magnetic stirring condition is necessary to be applicate in forming process. A reheating conditions were studied with the reheating time, holing time and reheating temperatures. The microstructure of SSM (which specimen size:d 40${\times}$i60) on condition of heating time 10min and heating temperature 590$^{\circ}C$ is most globular and finest one. The microstructure of SSM(specimen size:d75${\times}$i60) reheated under the three step reheating conditions is most globular and finest.

    • PDF

    (34141) Korea Institute of Science and Technology Information, 245, Daehak-ro, Yuseong-gu, Daejeon
    Copyright (C) KISTI. All Rights Reserved.