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1.
本文使用红外天文卫星(IRAS)巡天数据的最新版本IRAS天空巡天图(ISSA),经过进一步处理,得到了S140S141和S142SharplessHII区-分子云复合体的红外发射强度、温度及其光深的分布.在此基础上对各HII区的一些物理参量进行了统计分析,得到了分子云复合体的红外发射总光度以及复合体中尘埃的分布情况,对小尺度尘埃(VSG)的丰度进行了分析.并对各恒星形成区中的致密团块进行了研究,揭示出其中一些可能的恒星形成区域.同时,对S140区中的有关红外点源作出了能谱分析,并对S141区的激发星进行了讨论. 相似文献
2.
A THREE-DIMENSIONAL ELASTIC NESTED-GRID MESO-(β-γ)SCALE ATMOSPHERIC MODEL——PARTI:MODEL DESCRIPTION 下载免费PDF全文
A three-dimensional elastic nonhydrostatic mesoscale(β-γ)model with nested-grid is presented.It uses a set of fullequations in terrain-following coordinates as its basic dynamic frame,which is solved with a time-splitting algorithmfor acoustic and gravity waves.The model physical parameterization includes a K-theory subgrid eddy mixing for cloudand free atmosphere,a bulk planetary boundary layer parameterization,and three types of sofisticated cloudmicrophysics schemes with double-parameters for hail-bearing clouds,warm clouds and snowing clouds respectively.The model is designed to be used flexibly for simulations of a variety of meso-and small-scale atmospheric processes,and can be improved as a regional and local operational NWP system in future. 相似文献
3.
Farn Parungo Clarence Nagamoto Cecilia M. I. R. Girz Jeff Torgerson Zhou Mingyu 《海洋学报(英文版)》1995,14(2):201-207
ObservationofcloudsandsolarradiationoverthePacificOceanasrelationtoglobalclimate¥FarnParungo;ClarenceNagamoto;CeciliaM.I.R.Gi... 相似文献
4.
The mixing characteristics of particles such as dredged sediment of variable size discharged into cross flow are studied by a 3D numerical model, which is developed to model the particle-fluid two-phase flow. The Eulerian method with the modified k-ε parameterization of turbulence for the fluid phase is used to solve fluid phase, while a Lagrangian method for the solid phase (particles), both the processes are coupled through the momentum sources. In the model the wake turbulence induced by particles has been included as additional source term in the k-ε model; and the variable drift velocities of the particles are treated efficiently by the Lagrangian method in which the particles are tracked explicitly and the diffusion process is approximated by a random walk model. The hydrodynamic behavior of dumping a cloud of particles is governed by the total buoyancy of the cloud, the drag force on each particle and the velocity of cross-flow. The computed results show a roughly linear relationship between the displacement of the frontal position and the longitudinal width of the particle cloud. The particle size in the cloud and the velocity of cross flow dominate the flow behavior. The computed results are compared with the results of laboratory experiments and satisfactory agreement is obtained. 相似文献
5.
6.
Mi Ok Park 《Ocean Science Journal》2006,41(4):301-313
Abundance and distribution of phytoplankton in seawater at southwestern East/Japan Sea near Gampo were investigated by HPLC
analysis of photosynthetic pigments during summer of 1999. Detected photosynthetic pigments were chlorophyll a, b, c1+2 (Chl a, Chl b, Chl c1+2), fucoxanthin (Fuco), prasinoxanthin (Pras), zeaxanthin (Zea), 19’-butanoyloxyfucoxanthin (But-fuco) and beta-carotene (β-Car).
Major carotenoid was fucoxanthin (bacillariophyte) and minor carotenoids were Pras (prasinophyte), Zea (cyanophyte) and But-fuco
(chrysophyte). Chl a concentrations were in the range of 0.16-8.3/land subsurface chlorophyll maxima were observed at 0-10m
at inshore and 30–50 m at offshore. Thermocline and nutricline tilted to the offshore direction showed a mild upwelling condition.
Results from size-fraction showed that contribution from nano+picoplankton at Chl a maximum layer was increased from 18% at
inshore to 69% at offshore on average. The maximum contribution from nano+picoplankton was found as 87% at St. E4. It was
noteworthy that contribution from nano+picoplanktonic crysophytes and green algae to total biomass of phytoplankton was significant
at offshore. Satellite images of sea surface temperature indicated that an extensive area of the East/Japan Sea showed lower
temperature (<18 °C) but the enhanced Chl a patch was confined to a narrow coastal region in summer, 1999. Exceptionally high
flux of low saline water from the Korea/Tsushima Strait seemed to make upwelling weak in summer of 1999 in the study area.
Results of comparisons among Chl a from SeaWIFs, HPLC and fluorometric analysis showed that presence of Chl b cause underestimation
of Chl a about 30% by fluorometric analysis but overestimation by satellite data about 30-75% compared to HPLC data. 相似文献
7.
The purpose of this study is to validate and improve satellite-derived downward surface shortwave radiation (DSSR) over the northwestern Pacific Ocean using abundant in situ data. The DSSR derivation model used here assumes that the reduction of solar radiation by clouds is proportional to the product of satellite-measured albedo and a cloud attenuation coefficient. DSSR is calculated from Geostationary Meteorological Satellite-5/Visible Infrared Spin-Scan Radiometer data in 0.05° × 0.05° grids. The authors first compare the satellite DSSR derived with a cloud attenuation coefficient table determined in past research with in situ values. Although the hourly satellite DSSR agrees well with land in situ values in Japan, it has a bias of +13∼+34 W/m2 over the ocean and the bias is especially large in the low latitudes. The authors then improve the coefficient table using the ocean in situ data. Usage of the new table successfully reduces the bias of the satellite DSSR over the ocean. The cloud attenuation coefficient for low-albedo cases over the ocean needs to be larger in the low latitudes than past research has indicated. Daily and hourly DSSR can be evaluated from the satellite data with RMS errors of 11–14% and 30–33%, respectively, over a wide region of the ocean by this model. It is also shown that the cloud attenuation coefficient over land needs to be smaller than over the ocean because the effect of the radiation reflected by the land surface cannot be ignored. 相似文献
8.
本文主要对山东半岛东部、北部及渤海海峡地区的地方性天气-冷流低云,作了初步的分析。着重分析产生这种低云的环流特点及殊地理环境,分析归纳出这种低云的预测方法及判据。 相似文献
9.
Hydrodynamic modeling of flushing time in a small estuary of North Bay, Florida, USA 总被引:1,自引:0,他引:1
Freshwater fraction method is popular for cost-effective estimations of estuarine flushing time in response to freshwater inputs. However, due to the spatial variations of salinity, it is usually expensive to directly estimate the long-term freshwater fraction in the estuary from field observations. This paper presents the application of the 3D hydrodynamic model to estimate the distributions of salinity and thus the freshwater fractions for flushing time estimation. For a case study in a small estuary of the North Bay in Florida, USA, the hydrodynamic model was calibrated and verified using available field observations. Freshwater fractions in the estuary were determined by integrating freshwater fractions in model grids for the calculation of flushing time. The flushing time in the North Bay is calculated by the volume of freshwater fraction divided by the freshwater inflow, which is about 2.2 days under averaged flow conditions. Based on model simulations for a time series of freshwater inputs over a 2-year period, a power regression equation has been derived from model simulations to correlate estuarine flushing time to freshwater inputs. For freshwater input varying from 12 m3/s to 50 m3/s, flushing time in this small estuary of North Bay changes from 3.7 days to 1.8 days. In supporting estuarine management, the model can be used to examine the effects of upstream freshwater withdraw on estuarine salinity and flushing time. 相似文献
10.
M. E. Bailey 《Celestial Mechanics and Dynamical Astronomy》1992,54(1-3):49-61
Reasons for interest in the origin of short-period comets and the difficulties of computing their long-term dynamcal evolution are reviewed. The relative advantages of a source region in an extended inner core of the Oort cloud or a compact comet belt just beyond the planetary system are finely balanced, and it is premature to consider the problem solved. A complication is that some comets belonging to the Jupiter family may be part of a time-dependent system, possibly the remains of a giant comet such as Chiron which could have been part of the system 104 yr ago. The origin of short-period comets plays a pivotal role in many areas of solar system science: planet formation, the source of water (possibly life) on the terrestrial planets, the cratering record on the terrestrial planets and satellites of the outer planets, and the environmental impact posed by massive bodies and their decay products in the Earth's near-space environment. 相似文献