Attitude estimation method for small UAV under accelerative environment     

Heekwon No  Am Cho  Changdon Kee 《GPS Solutions》2015,19(3):343-355

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The 27 July 2011 debris flows at Umyeonsan,Seoul, Korea   总被引：1，自引：1，他引：0  

Sangseom Jeong  Yongmin Kim  Joon Kyu Lee  Junghwan Kim 《Landslides》2015,12(4):799-813

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Detection of contaminated pixels based on the short-term continuity of NDVI and correction using spatio-temporal continuity     

A-Ra Cho  Myoung-Seok Suh 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(4):511-525

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Photochemical characteristics of high and low ozone episodes observed in the Taehwa Forest observatory (TFO) in June 2011 near Seoul South Korea     

Soyoung Kim  Meehye Lee  Suyeon Kim  Soonho Choi  Sonjung Seok  Saewung Kim 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(3):325-331

We present a comprehensive discussion on what cause high ozone episodes at a suburban photochemical observation site of the Seoul Metropolitan Area (population ～23 million). The observational site, Taehwa Research Forest (TRF), is situated ～30 km from the center of Seoul. In June 2011, we observed two very distinctive ozone periods-high ozone (peak up to 120 ppbv) and low ozone (peak up to 60 ppbv) in the mid and early month, respectively. The trace gas measurement dataset, especially CO and NO _X clearly indicate that less anthropogenic influences during the high ozone period. Volatile organic compound (VOC) measurement results show that at the observational site, biogenic VOCs (mostly isoprene) contribute most of chemical reactivity towards OH, although toluene from anthropogenic activities was observed in higher concentrations. Back-trajectory analysis indicates that air-masses from the forest part of Korea Peninsula were dominant influences during the high ozone episode event. On the other hand, Aged air masses from China were the dominant influence during the low ozone episode event. Model calculations conducted using the University of Washington Chemical Mechanism (UWCM) box model, also consistently show that BVOC, especially isoprene photochemistry, can be the significantly contribution to local ozone formation in the given photochemical environments of TRF. These research results strongly suggest that ozone control strategy in the Eastern Asian megacities, mostly situated in surrounding forest areas should be based on the comprehensive scientific understanding in BVOC photochemistry and interplays between anthropogenic and biogenic interactions.  相似文献   

Climate change in the 21st century simulated by HadGEM2-AO under representative concentration pathways   总被引：2，自引：0，他引：2  

Hee-Jeong Baek  Johan Lee  Hyo-Shin Lee  Yu-Kyung Hyun  ChunHo Cho  Won-Tae Kwon  Charline Marzin  Sun-Yeong Gan  Min-Ji Kim  Da-Hee Choi  Jonghwa Lee  Jaeho Lee  Kyung-On Boo  Hyun-Suk Kang  Young-Hwa Byun 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(5):603-618

We present climate responses of Representative Concentration Pathways (RCPs) using the coupled climate model HadGEM2-AO for the Coupled Model Intercomparison Project phase 5 (CMIP5). The RCPs are selected as standard scenarios for the IPCC Fifth Assessment Report and these scenarios include time paths for emissions and concentrations of greenhouse gas and aerosols and land-use/land cover. The global average warming and precipitation increases for the last 20 years of the 21st century relative to the period 1986-2005 are +1.1°C/+2.1% for RCP2.6, +2.4°C/+4.0% for RCP4.5, +2.5°C/+3.3% for RCP6.0 and +4.1°C/+4.6% for RCP8.5, respectively. The climate response on RCP 2.6 scenario meets the UN Copenhagen Accord to limit global warming within two degrees at the end of 21st century, the mitigation effect is about 3°C between RCP2.6 and RCP8.5. The projected precipitation changes over the 21st century are expected to increase in tropical regions and at high latitudes, and decrease in subtropical regions associated with projected poleward expansions of the Hadley cell. Total soil moisture change is projected to decrease in northern hemisphere high latitudes and increase in central Africa and Asia whereas near-surface soil moisture tends to decrease in most areas according to the warming and evaporation increase. The trend and magnitude of future climate extremes are also projected to increase in proportion to radiative forcing of RCPs. For RCP 8.5, at the end of the summer season the Arctic is projected to be free of sea ice.  相似文献   

Ecosystem responses to climate change in a large on-river reservoir, Lake Paldang, Korea   总被引：3，自引：0，他引：3  

Hae-Kyung Park  Kang-Hyun Cho  Doo Hee Won  Jangho Lee  Dong-Soo Kong  Dong-Il Jung 《Climatic change》2013,120(1-2):477-489

The impact of climate change on a large river reservoir ecosystem was investigated. Long-term meteorological data showed that recent climate change, including warmer winters, increased precipitation intensity and extended dry periods, may have influenced the basin of Lake Paldang, the most downstream reservoir of a series of on-river reservoirs. Extreme hydrologic events and climate warming, acting independently and in combination, appear to be related to changes in the Lake Paldang ecosystem. A significant increase in chlorophyll a concentrations in early spring corresponded to the timing of ice break-up. An increase in winter temperatures, which resulted in a shorter time period of ice-cover and earlier ice break-up, appears to have stimulated phytoplankton growth in winter and early spring. Repeated intensive and extended influxes of turbid water, associated with more frequent extreme rainfall events, have increased concentration of suspended solids and may have influenced the biotic community structure of Lake Paldang. In the mid-2000s, the area vegetated by submerged hydrophytes, the abundance and biomass of the phylum Mollusca, as well as the abundance of fish from the subfamily Acheilognathinae, which spawn in the body of bivalve molluscs, was all smaller than in the late 1980s and early 1990s. Together, these results suggest that climate change may have contributed directly and indirectly to changes in each trophic level of the Lake Paldang ecosystem.  相似文献   

Active Region Coronal Rain Event Observed by the Fast Imaging Solar Spectrograph on the NST     

Kwangsu Ahn  Jongchul Chae  Kyung-Suk Cho  Donguk Song  Heesu Yang  Philip R. Goode  Wenda Cao  Hyungmin Park  Jakyung Nah  Bi-Ho Jang  Young-Deuk Park 《Solar physics》2014,289(11):4117-4136

The Fast Imaging Solar Spectrograph (FISS) is being operated on the New Solar Telescope of the Big Bear Solar Observatory. It simultaneously records spectra of Hα and Ca ii 8542 Å lines, and this dual-spectra measurement provides an estimate of the temperature and nonthermal speed components. We observed a loop structure in AR 11305 using the FISS, SDO/AIA, and STEREO/EUVI in 304 Å, and found plasma material falling along the loop from a coronal height into the umbra of a sunspot, which accelerated up to 80 km?s^?1. We also observed C2 and C7 flare events near the loop. The temperature of the downflows was in the range of 10?000?–?33?000 K, increasing toward the umbra. The temperature of the flow varied with time, and the temperature near the footpoint rose immediately after the C7 flare, but the temperature toward the umbra remained the same. There seemed to be a temporal correlation between the amount of downflow material and the observed C-class flares. The downflows decreased gradually soon after the flares and then increased after a few hours. These high-speed red-shift events occurred continuously during the observations. The flows observed on-disk in Hα and Ca ii 8542 Å appeared as fragmented, fuzzy condensed material falling from the coronal heights when seen off-limb with STEREO/EUVI at 304 Å. Based on these observations, we propose that these flows were an on-disk signature of coronal rain.  相似文献   

Revisiting Solar and Heliospheric 1.3-Year Signals during 1970 – 2007     

I.-H. Cho  J. Hwang  Y.-D. Park 《Solar physics》2014,289(3):707-719

We revisit the 1.3-year (yr) signals observed on the Sun, in the interplanetary space, and in the Earth’s magnetosphere to study the coupling among signals from the three regions for about 40 years (1970?–?2007) covering the three solar cycles 21, 22, and 23. For this, we make dynamic spectra of datasets including three different regions. From this, we estimate the peak frequency around 1.3 yr for each region and the corresponding band power. We found that coherent power only appears during 1987?–?1995 and the coherent behavior is found only in the interplanetary space and Earth, not in the Sun. Although the solar surface magnetic field shows significant power around 1.3 yr, their peak frequencies are statistically different from those of the outer regions, which make us dismiss the existence of coherence among the three regions. But it is notable that the peaks in band power corresponding to the 1.3-yr period are clearly simultaneous in the interplanetary space and Earth.  相似文献   

Simultaneous solutions for photometric and spectroscopic observations of TX UMa     

Young Woon Kang  Kyu Dong Oh 《Astrophysics and Space Science》1993,201(2):177-189

B andV light curves for one epoch and radial velocity curves of three different epochs have been analyzed to revise the solution of TX UMa. The solution has been adjusted simultaneously in the light curves and radial velocity curves by the method of Wilson and Devinney's differential correction. The primary star's surface rotation rate to synchronous rate is determined as 1.768 from one of the radial velocity curves. The absolute dimension of the system has been deduced based on the simultaneous solution. The primary star is well fitted to the evolutionary track for a single star while the secondary star, while filling its Roche lobe, is fitted to the evolutionary track for a close binary system.  相似文献   

APEX-SZ a Sunyaev–Zel’dovich galaxy cluster survey     

D. Schwan  F. Bertoldi  S. Cho  M. Dobbs  R. Guesten  N. W. Halverson  W. L. Holzapfel  E. Kreysa  T. M. Lanting  A. T. Lee  M. Lueker  J. Mehl  K. Menten  D. Muders  M. Myers  T. Plagge  A. Raccanelli  P. Schilke  P. L. Richards  H. Spieler  M. White 《New Astronomy Reviews》2003,47(11-12):933

The APEX-SZ experiment is a sky survey designed to discover galaxy clusters via the Sunyaev–Zel’dovich effect at millimeter wavelengths. We describe the components of the instrument, including the 12 m Atacama Pathfinder Experiment telescope, optics, Transition-edge sensor bolometer array and SQUID readout. APEX-SZ will begin observations in 2004.  相似文献