排序方式： 共有55条查询结果，搜索用时 15 毫秒
41.
Evaluation of statistical gap fillings for continuous energy flux (evapotranspiration) measurements for two different land cover types 总被引：1，自引：0，他引：1
42.
Geumsook Park Bon-Chul Koo Kee-Tae Kim Do-Young Byun Carl E. Heiles 《Astrophysics and Space Science》2018,363(7):150
As part of the search for the “dark molecular gas (DMG),” we report on the results of HCO+\(J=1\mbox{--}0\) absorption observations toward nine bright extragalactic millimeter wave continuum sources. The extragalactic sources are at high Galactic latitudes (\(|b| > 10^{\circ} \)) and seen at small extinction (\(E(B - V)\lesssim 0.1\) mag). We have detected the HCO+ absorption lines toward two sources, B0838+133 and B2251+158. The absorption toward B2251+158 was previously reported, while the absorption toward B0838+133 is a new detection. We derive hydrogen column densities or their upper limits toward the nine sources from our observations and compare them to those expected from CO line emission and far-infrared dust continuum emission. Toward the seven sources with no HCO+ detection, CO emission has not been detected, either. Thus the sight lines are likely to be filled with almost pure atomic gas. Toward the two sources with HCO+ detection, CO emission has been also detected. Comparison of the H2 column densities from HCO+ absorption and CO emission suggests a non-negligible amount of DMG toward B0838+133. 相似文献
43.
Alcock C. Dave R. Giammarco J. Goldader J. Lehner M. King S.-K. Lee T. Wang A. Wang S.-Y. Wen C.-Y. Chen W. P. Cook K. Marshall S. Porrata R. Byun Y.-I. de Pater I. Rice J. Lissauer J. 《Earth, Moon, and Planets》2003,92(1-4):459-464
The Taiwanese–American Occultation Survey (TAOS) seeks to determinethe number and size spectrum for small (～3 km) bodies in the KuiperBelt. This will be accomplished by searching for the brief occultations of brightstars (R～14) by these objects. We have designed and built a specialpurpose photometric monitoring system for this purpose. TAOS comprisesfour 50 cm telescopes, each equipped with a 2048×2048 pixel CCDcamera, in a compact array located in the central highlands of Taiwan. TAOSwill monitor up to 3,000 stars at 5 Hz. The system will go into scientificoperation at the end of 003. 相似文献
44.
Satellite orbit determination using triple-differenced GPS carrier phase in pure kinematic mode 总被引：1，自引：0，他引：1
S. H. Byun 《Journal of Geodesy》2003,76(9-10):569-585
45.
This study compares the impacts of El Ni?o Modoki and El Ni?o on precipitation over Korea during the boreal winters from 1954 to 2009. Precipitation in Korea tends to be equal to or greater than the normal level during an El Ni?o Modoki winter, whereas there is no significant change during an El Ni?o winter. Greater than normal precipitation during El Ni?o Modoki was also found over the lower reaches of the Yangtze River, China and much of southern Japan. The latitudes of these regions are 5–10° further north than in southern China, where precipitation increases during El Ni?o. The following two anomalous atmospheric circulations were found to be causes that led to different precipitation distributions over East Asia. First, an atmospheric wave train in the lower troposphere, which propagated from the central tropical Pacific (cyclonic) through the southern Philippine Sea (anticyclonic) to East Asia (cyclonic), reached the southern China and northern Philippine Sea during El Ni?o, whereas it reached Korea and southern Japan during El Ni?o Modoki. Second, an anomalous local meridional circulation, which consists of air sinking in the tropics, flowing poleward in the lower troposphere, and rising in the subtropics, developed between the southern Philippine Sea and northern Philippine Sea during El Ni?o. During El Ni?o Modoki, however, this circulation expanded further to the north and was formed between the southern Philippine Sea and regions of Korea and southern Japan. 相似文献
46.
Chang-Woong Shin Sang-Kyung Byun Cheolsoo Kim Jae Hak Lee Bong-Chae Kim Sang-Chull Hwang Young Ho Seung Hong-Ryeol Shin 《Ocean Science Journal》2013,48(1):35-47
Seasonal variations in the low-salinity intermediate water (ESIW) in the region south of the sub-polar front of the East Sea were investigated by using historical hydrographic data. The salinity of the representative density (sigma-0=27.2) of the ESIW was minimal in summer and maximal in winter in the region south of the sub-polar front. The selected four subregions showed different salinity variations. In the west of Oki Spur and the Yamato Basin, salinity fluctuated similarly, with a minimum during summer. In the Ulleung Basin and northwest of Sado Island, however, variations in salinity showed two minima, one is in winter and the other is in summer. These results imply differences in the flow path of the ESIW into the region south of the sub-polar front over time. 相似文献
47.
We have developed a control system for the Seoul Radio Astronomy Observatory (SRAO) 6-meter telescope operating in the 85–115
Ghz frequency range. Four PCs running the Linux operating system control source tracking, take data, execute observations
and handle user interface. The control system utilizes a modular and multiprocessing structure to facilitate easy upgrading
and troubleshooting. Communication between the processes relies on the interprocess communication (IPC) resources on Linux
such as shared memory, message queues, and TCP/IP sockets. Communication between PCs is made via an Ethernet link. We also
use digital I/O lines for some status signals which require a short delay. The control system supports scheduling observations,
updates observation logs automatically and also supports graphical user interfaces. These all makes the operation easy. By
using a commercially available motion control card with an embedded microcomputer for antenna control, we achieved a tracking
accuracy to
better than 1 arcsec.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
48.
Determining ‘photosynthetically active radiation’ (PAR) is a key part of calculating phytoplankton productivity in a biogeochemical
model. We explore the daily and seasonal variability in the ratio of PAR irradiance to total irradiance that occurred at Ieodo
Ocean Research Station (IORS) in the East China Sea under clear-sky conditions in 2004 using a simple radiative transfer model
(RTM). Meteorological data observed at IORS and aerosol optical properties derived from Aerosol Robotic Network observations
at Gosan are used for the RTM. Preliminary results suggest that the use of simple PA R irradianceratio values is appropriate
in calculating phytoplankton productivity as follows: an average of 0.44 (±0.01) in January to an average of 0.48 (±0.01)
in July, with average daily variabilities over these periods of about 0.016 (±0.008) and 0.025 (±0.008), respectively. The
model experiments demonstrate that variations in the major controlling input parameters (i.e. solar zenith angle, precipitable
water vapor and aerosol optical thickness) cause PAR irradiance ratio variation at daily and seasonal timescales. Further,
increases (>0.012) in the PAR irradiance ratio just below the sea-surface are positively correlated with high solar zenith
angles and strong wind stresses relative to those just above the sea-surface. 相似文献
49.
Daewon W. Byun 《Boundary-Layer Meteorology》1991,57(1-2):17-48
Functional forms of the universal similarity functions A, B (for wind components parallel and normal to the surface stress), and C (for potential temperature difference) are determined based on the generalized theory of the resistance laws for the Planetary Boundary Layer (PBL). The similarity-profile functions for the surface layer are matched with the velocity and temperature-defect profiles that are assumed to have shapes modified by certain powers of nondimensional height z/h, where h is the PBL height. The powers of the outer-layer profile functions are determined, so that the functions become negligible in the surface layer. To close the temperature defect law, an assumption that the temperature gradient across the top of the PBL is continuous with the stratification of the overlying atmosphere is used. The result of this assumption is that nondimensional momentum and temperature profiles in the PBL can be described in terms of four basic ratios: (1) roughness ratio = /h (2) scale-height ratio =|f|h/u*, (3) ambient stratification parameter =h/*, and (4) stability parameter =h/L, where L is the Monin-Obukhov length, z0 is the surface roughness, is the upper-air stratification, u
* is the friction velocity, and
* is the temperature scale at the surface. For stable conditions, the scale-height ratio can be related to the atmospheric stability and the upperair stratification, and the generalized similarity and Rossby number similarity theories become identical. Under appropriate boundary conditions, function A is explicitly dependent on the stability parameter , while B is a function of scale-height ratio , which in turn depends on the stability. Function C is shown to be dependent on the stability and the upper-air stratification, due to the closure assumption used for the temperature profile.The suggested functional forms are compared with other empirical approximations by several authors. The general framework used to determine the functional forms needs to be tested against good boundary-layer measurements. 相似文献
50.
Suryun Ham Song-You Hong Young-Hwa Byun Jhoon Kim 《Journal of Atmospheric and Solar》2009,71(17-18):1924-1934
The purpose of this study is to investigate the effects of precipitation physics in a general circulation model (GCM) on a simulated climate. Experiments are performed under the single column model (SCM) framework to examine basic features and under the general circulation model framework to investigate the impact on seasonal simulation. The SCM simulation shows that convection processes in the model have a considerable influence on the change in vertical thermodynamic structure, resulting in a change in precipitation, whereas in the GCM framework stratiform precipitation physics play a distinct role in changing the atmospheric structure. The GCM experiments also show that the overall reduction of precipitation in simulations with prognostic stratiform precipitation physics is highly related to changes in cloudiness and corresponding changes in radiative flux, which in turn leads to the reduction of convective activities. 相似文献