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1.
Analysis of ERS-2 scatterometer winds and wind-wave calculation for eastern China seas 总被引：1，自引：0，他引：1
The wind system over the China seas plays an important role in climate variation there. In this paper, ERS-2 scatterometer winds covering the period of 1998 and the area of 25-41°N, 117-130°E were analyzed and compared to NCEP winds and buoy winds in the same period and location, to assess how well the ERS-2 data reflect the real wind regime, at least for this area. The results indicated that ERS-2 scatterometer winds are closer to buoy observations than NCEP winds. In addition, a new wind-wave growth relation was applied to calculate wave parameters. 相似文献
2.
The effect of ocean wave breaking as a non-Bragg mechanism on backscattering cross-section and modulation transfer functions （MTF） of radar was investigated based on Bragg resonance theory and parametric method. The result showed that the additional effect of wave breaking on backscattering cross-section is not more than 20% except for the small incident angle of VV polarized electromagnetic （e.m.） wave but is significant for HH polarized e.m. wave. Breaking waves lead to increase in the modulus of tilt modulation MTF and the larger the wind speed, the faster the increase. For large incident angle, the modulus of tilt modulation MTF with wave breaking decreases quickly with incident angle for HH polarization and approach to that without wave breaking for VV polarization. The hydrodynamic MTF increases 30%-60% when considering wave breaking and the increase is larger for HH polarization than for VV polarization. 相似文献
3.
Comparison of two wind algorithms of ENVISAT ASAR at high wind 总被引：1，自引：0，他引：1
Two wind algorithms of ENVISAT advanced synthetic aperture radar (ASAR), i. e. CMOD4 model from the European Space Agency (ESA) and CMOD IFR2 model from Quilfen et al., are compared in this paper. The wind direction is estimated from orientation of low and linear signatures in the ASAR imagery. The wind direction has inherently a 180° ambiguity since only a single ASAR image is used. The 180° ambiguity is eliminated by using the buoy data from the NOAA (National Oceanic and Atmospheric Administration) buoys moored in the Pacific. Wind speed is obtained with the two wind algorithms using both estimated wind direction and normalized radar cross section (NRCS). The retrieved wind results agree well with the data from Quikscat. The root mean square error (RMSE) of wind direction is 2.80? The RMSEs of wind speed from CMOD4 model and CMOD_IFR2 model are 1.09 m/s and 0.60 m/s, respectively. The results indicate that the CMOD_IFR2 model is slight better than CMOD4 model at high wind. 相似文献
4.
REN Chunying ZHANG Bai WANG Zongming SONG Kaishan LIU Dianwei LIU Zhiming 《中国地理科学(英文版)》2007,17(4):333-340
Based on Tupu theory, this paper studied the dynamic changes, conversion modes, expansion intensity and landscape attributes of the saline-alkali lands in Changling County, Zhenlai County and Da'an City of the western Jilin Province in 1980-2000 with the help of GIS. The results show that the saline-alkali land rather sharply increased in Da'an during 1995-2000; the main conversion processes in the three counties were from grassland to saline-alkali land and from saline-alkali land to grassland; and the typical shapes, spatial expansion speed and mode, and landscape attributes of the saline-alkali land were different in the three counties, which were closely related to local topography, predominant wind orientation, water resources distribution, etc. The corresponding spatial expansion mode was marginality in Changling, random in Zhenlai and more kernels in Da'an, respectively. Landscape attributes also responded to the spatial-temporal dynamic changes of the saline-alkali land and the landscape indices of Da'an fluctuated greatly. The frame of this research may provide fundamental reference for landscape analysis and give some suggestions for regional sustainable development. 相似文献
5.
With the aid of Meteorological Information Composite and Processing System （MICAPS）, satellite wind vectors derived from the Geostationary Meteorological Statellite-5 （GMS-5） and retrieved by National Satellite Meteorology Center of China （NSMC） can be obtained. Based on the nudging method built in the fifth-generation Mesoscale Model （MM5） of Pennsylvania State University and National Center for Atmospheric Research, a data preprocessor is developed to convert these satellite wind vectors to those with specified format required in MM5. To examine the data preprocessor and evaluate the impact of satellite winds from GMS-5 on MM5 simulations, a series of numerical experimental forecasts consisting of four typhoon cases in 2002 are designed and implemented. The results show that the preprocessor can process satellite winds smoothly and MM5 model runs successfully with a little extra computational load during ingesting these winds, and that assimilation of satellite winds by MM5 nudging method can obviously improve typhoon track forecast but contributes a little to typhoon intensity forecast. The impact of the satellite winds depends heavily upon whether the typhoon bogussing scheme in MM5 was turned on or not. The data preprocessor developed in this paper not only can treat GMS-5 satellite winds but also has capability with little modification to process derived winds from other geostationary satellites. 相似文献
6.
Study on the dominant species of Pteropoda in East China Sea 总被引：2，自引：0，他引：2
1 INTRODUCTION Pteropoda is a group of marine pelagic mol- lusks, which belongs to Opisthobranchia of Gastro- poda. Although Pteropoda is not a major group in pelagic zooplankton in terms of abundance and number of species, their ecological characters are… 相似文献
7.
Using the latest version of Mesoscale Modeling System (MM5v3), we assimilated wind data from the scatterometer and built a model to assimilate the wind field over eastern China seas and adjacent waters and applied the wave model WAVEWATCH-Ⅲ to test the sea area with assimilative wind and blended wind of QSCAT and NCEP as driving forces. High precision and resolution numerical wave results were obtained. Analysis indicated that if we replace the model wind result with the blended wind, better sea surface wind results and wave results could be obtained. 相似文献
8.
1 INTRODUCTIONIt is well known that wind-generated wavestorm surge and atmospheric circulation as impor-tant ocean weather events are closely related tomomentum exchange between sea and atmosphere(Oncley and Dudhia, 1995). For this reason, in thepast 20 years, attention has been directed towardshow to better describe momentum exchange throughsea surface. In general, to precisely determine theexchange, improvement should be made in the as-pects of reasonably depicting the roughness de-pend… 相似文献
9.
Six steroids have been isolated from ethanolic extract of green alga Chaetomorpha basiretorsa Setchell by a combination of repeated normal phase silica gel and Sephadex LH-20 gel column chromatography as well as recrystallization. Using spectroscopic methods including MS and NMR, their structures were determined as β-1awsaritol （1）, saringosterol （2）, 24-hydroperoxy-24-vinyl- cholesterol （3）, β-stigmasterol （4）, stigmast-4-en-3α, 6β-diol （5）, 29-hydroxystigmasta-5, 24 （28）-dien-3β-ol （6）. All these compounds were obtained from this genus for the first time and they were inactive （IC50〉10μg/ml） against KB, Bel-7402, PC-3M, Ketr 3 and MCF-7 cell lines. 相似文献
10.
11.
Studying the relationship between wave steepness and wave age is important for describing wind wave growth with energy balance equation of significant waves. After invoking the dispersion rela- tion of surface gravity wave in deep water, a new relationship between wave steepness and wave age is revealed based on the “3/2-power law” (Toba, 1972), in which wave steepness is a function of wave age with a drag coefficient as a parameter. With a given wave age, a larger drag coefficient would lead to larger wave steepness. This could be interpreted as the result of interaction between wind and waves. Comparing with previous relationships, the newly proposed one is more consistent with observational data in field and laboratory. 相似文献
12.
The relationships between the neon flying squid, Ommastrephes bartrami, and the relative ocean environmental factors are analyzed. The environmental factors collected are sea surface temperature
(SST), chlorophyll concentration (Chl-a) and sea surface height (SSH) from NASA, as well as the yields of neon flying squid in the North Pacific Ocean. The results
show that the favorable temperature for neon flying squid living is 10°C–22°C and the favorite temperature is between 15°C–17°C.
The Chl-a concentration is 0.1–0.6 mg/m3. When Chl-a concentration changes to 0.12–0.14 mg/m3, the probability of forming fishing ground becomes very high. In most fishing grounds,
the SSH is higher than the mean SSH. The generalized additive model (GAM) was applied to analyze the correlations between
neon flying squid and ocean environmental factors. Every year, squids migrate northward from June to August and return southward
during October–November, and the characteristics of the both migrations are very different. When squids migrate to the north,
most relationships between the yields and SST are positive. The relationships are negative when squids move to southward.
The relationships between the yields and Chl-a concentrations are negative from June to October, and insignificant in November. There is no obvious correlation between
the catches of squid and longitude, but good with latitude.
Supported by the National High Technology Research and Development Program of China (863 Program, No. 2003AA607030); National
Key Technology Research and Development Program (No. 2006BAD09A05) 相似文献
13.
The upper ocean response to tropical cyclones in the northwestern Pacific analyzed with Argo data 总被引：3，自引：0，他引：3
A large number of autonomous profiling floats deployed in global oceans have provided abundant temperature and salinity profiles of the upper ocean. Many floats occasionally profile observations during the passage of tropical cyclones. These in-situ observations are valuable and useful in studying the ocean’s response to tropical cyclones, which are rarely observed due to harsh weather conditions. In this paper, the upper ocean response to the tropical cyclones in the northwestern Pacific during 2000–2005 is analyzed and discussed based on the data from Argo profiling floats. Results suggest that the passage of tropical cyclones caused the deepening of mixed layer depth (MLD), cooling of mixed layer temperature (MLT), and freshening of mixed layer salinity (MLS). The change in MLT is negatively correlated to wind speed. The cooling of the MLT extended for 50–150 km on the right side of the cyclone track. The change of MLS is almost symmetrical in distribution on both sides of the track, and the change of MLD is negatively correlated to pre-cyclone initial MLD. 相似文献
14.
Ding Zongxin 《中国海洋湖沼学报》1985,3(1):109-117
In this paper the influences of short-term wind on vertical structures of temperature and salinity, and the upwelling off
the Zhejiang coast are studied on the basis of hydrographic data and wind near the coast in Summer (1959–1979). It is pointed
out that the variations of vertical distributions of temperature and salinity, and upwelling in this region are closely related
to short-term (several days to a week) variation of wind observed. The occurrence of double thermocline, a special oceanographic
phenomenon, is partially related to unstable SSW wind field. SSW and NE winds in June are two dynamic factors making intermediate
warm water form or disappear.
Contribution No. 792 from the Institute of Oceanology, Academia Sinica.
This paper was published in Chinese inOceanologia et Limnologia Sinica
14 (1): 14–21, 1983. 相似文献
15.
16.
Projections of wind changes for 21st century in China by three regional climate models 总被引：1，自引：0，他引：1
This paper examines the capability of three regional climate models(RCMs),i.e.,RegCM3(the International Centre for Theoretical Physics Regional Climate Model),PRECIS(Providing Regional Climates for Impacts Studies)and CMM5(the fifth-generation Pennsylvania State University-the National Center for Atmospheric Research of USA,NCAR Mesoscale Model)to simulate the near-surface-layer winds(10 m above surface)all over China in the late 20th century.Results suggest that like global climate models(GCMs),these RCMs have the certain capability of imitating the distribution of mean wind speed and fail to simulate the greatly weakening wind trends for the past 50 years in the country.However,RCMs especially RegCM3 have the better capability than that of GCMs to simulate the distribution and change feature of mean wind speed.In view of their merits,these RCMs were used to project the variability of near-surface-layer winds over China for the 21st century.The results show that 1)summer mean wind speed for 2020-2029 will be lower compared to those in 1990-1999 in most area of China; 2)annual and winter mean wind speed for 2081-2100 will be lower than those of 1971-1990 in the whole China; and 3)the changes of summer mean wind speed for 2081-2100 are uncertain.As a result,although climate models are absolutely necessary for projecting climate change to come,there are great uncertainties in projections,especially for wind speed,and these issues need to be further explored. 相似文献
17.
Cassini growth of population between two metropolitan cities—A case study of Beijing-Tianjin region, China 总被引：1，自引：0，他引：1
The existing models of population distribution often focus on the region with a single city or even multiple centers, and
lack the detailed explorations of the common and special type of urbanization areas with two centers. Taking Beijing-Tianjin
region of China, which is a distinct dual-nuclei metropolitan area in the world, as an example and choosing Landsat-5 TM image
in 2005, population, etc. as the data, this paper devotes to comprehending and illustrating a model of Cassini growth of population
between the two metropolitan cities through the research of spatial population distribution pattern, aided with RS and GIS
techniques. Main technical processes include Kriging interpolation of the population data and character simulation of the
Cassini ovals. According to the calculation of a/b, a key characteristic index of Cassini growth model, the spatial structures of population distribution were given. When a/b<1, it is a curve with two separated loops with a population density more than 3000 persons/km2. When a/b=1, it is a lemniscate curve with a population density about 3000 persons/km2. When 1<a/b√2, it is a dog-bone shaped concave curve with a population density between 500–3000 persons/km2. When a/b=√2, it is an oblate curve with a population density about 500 persons/km2. When a/b>√2, there is an oval-shaped convex curve with a population density less than 500 persons/km2. The results show that owing to the combined action and influence of the regional dual-nuclei, the population distribution
of Beijing-Tianjin region is in accord with Cassini model significantly. There-fore, there is Cassini growth of population
between the two metropolitan cities in Beijing-Tianjin region. In addition, the process of Cassini growth has extraordinarily
instructive significance for judging the development stages of the dual-nuclei metropolitan areas.
Foundation item: Under the auspices of National High-Tech Research and Development Program of China (863 Program) (No. 2007AA12Z235),
National Natural Science Foundation of China (No. 40471058) 相似文献
18.
Surface water can be divided into three layers from top downward: surface microlayer (SML, thickness≤50 μm), subsurface layer (SSL, ≈25 cm) and surface layer (SL, 1–5m), among which the SML plays an important role on sea-air interaction because of its unique physical-chemical property. Carbon dioxide system including DIC (dissolved inorganic carbon), Alk (alkalinity), pH and pCO2 (partial pressure of CO2) in multilayered waters of the Yellow Sea was studied for the first time in March and May 2005. The results show that: DIC and Alk are obviously enriched in SML. The contents of DIC, Alk and pCO2 become lower in turn from SML, SSL to SL, higher in March and lower in May, whereas for pH it was opposite. The relationship between DIC and Alk is clearly positive, but negative between pH and pCO2. Meanwhile, pCO2 and temperature/salinity is also in positive relation, pCO2 decreases with latitude increase. DIC and Alk show a similar variation trend with the maximum at 02:00–03:00, but pH and pCO2 show an opposite pattern. In addition, the distribution patterns are similar to each other in the three layers. The Yellow Sea is shown to be a sink of atmospheric CO2 in spring by two methods: (1) comparing pCO2 in seawater and atmosphere; (2) turning direction of “pH-depth” curve. Calculation on the base of pCO2 data in SML in four models shows that carbon flux in spring in the area was about -6.96×106 t C. 相似文献
19.
Distribution of heavy metals and nutrients in rainwater in coastal regions between the southern Yellow Sea and East China Sea 总被引：2，自引：0，他引：2
Rainwater samples were collected in series in Qianliyan Island (southern Yellow Sea) and Shengsi Archipelago (East China Sea) between May 2000 and May 2002, chemical analysis for pH values,concentrations of heavy metals (Cu, Pb, Zn and Cd) and nutrients (NH4^-, NO3^-, PO43^-, SiO32^-) were performed.Results indicate that concentrations of most of the heavy metals and nutrients in rainwater show clear seasonal variation, i.e. high level in winter and low level in summer. Regionally, concentrations are higher in the southern Yellow Sea than in the East China Sea, but the annual input of heavy metals into oceans by wet deposition is similar in both stations. However, the input of nutrients by wet deposition in the East China Sea is 2-3 times higher than that in the southern Yellow Sea. In individual, Pb and PO4^3- are input to the sea mainly by dry deposition; whereas Cu, Zn, Cd and N compounds are input dominantly by wet deposition, the N/P ratios in the rainwater from two stations are much higher than those in seawater, showing a significant impact of atmospheric wet deposition on marine production and biogeochemical circulation of nutrients in these sea regions. 相似文献
20.
Warming trend in northern East China Sea in recent four decades 总被引：2，自引：0，他引：2
Global warming has become a notable trend especially since an abrupt climate change in 1976. Response of the East China Sea (ECS) to the global warming trend, however, is not well understood because of sparse long-term observation. In this paper, hydrographic observation data of 1957–1996 are collected and reviewed to study climatological variability in northern ECS. Significant warming trends are found in both summer and winter. In summer, the average SST is about 0.46°C higher during the period of 1977-19... 相似文献