In order to decipher phenomenon of tree line changing with climate variety, the trend of tree line on the northern slope of Changbai Mountain was studied. Based on the meteorological data of Changbai Mountain, the Jan...In order to decipher phenomenon of tree line changing with climate variety, the trend of tree line on the northern slope of Changbai Mountain was studied. Based on the meteorological data of Changbai Mountain, the January temperature (the limiting effect for tree line) and annual mean temperature were mainly investigated. In the ecotone between Betula ermanii and alpine tundra, the number and diameter at ground level of Betula ermanii in the plots were measured. According to the correlation between diameter at ground level (DGL) and age, the diameter at ground level can represent age directly. The results showed that the distribution age of Betula ermanii was in the trend of decreasing with elevation rising. In resent years, the annual mean temperature near Changbai Mountain is rising, which has led to the tree line ascending.展开更多
By the method of gradient pattern analysis, twenty plots were set at altitudes of 700-2600 m with an interval of 100 m on the northern slope of the Changbai Mountain. The dissimilarity of respective sub-plots in the s...By the method of gradient pattern analysis, twenty plots were set at altitudes of 700-2600 m with an interval of 100 m on the northern slope of the Changbai Mountain. The dissimilarity of respective sub-plots in the same community was measured and the complexity of plant communities at different altitudes was analyzed. The result from binary data of tree species in canopy tree indicated that the sub-plots in the communities, except subalpine Betula ermanii forest, showed comparatively high dissimilarity in species composition. Especially, the dissimilarity index (0.7) of broadleaved/Korean pine forest at low altitudes was obviously higher than other communities. The differences are not obvious between communities referring to dark coniferous forest. Comparatively, the dissimilarity in sub-plots of the communities at altitude of 1400 m was slightly higher than that of other communities, which reflected the complexity of tree species compositions of transitory-type communities. For subalpine Betula ermanii forest, tree species composition was simple and showed a high similarity between sub-plots. The results derived from binary data of shrub showed that the dissimilarity index of shrub species in broadleaved/Korean pine forest at low altitudes was higher than that in other communities, but the divergence tendency wasn抰 so obvious as that of arbor species. The dissimilarity derived from binary data of herb and all plant species at different altitudes showed greatly close tendency, and the differences in herb and all plant species between sub-plots were the greatest for the communities of broad-leaved-Korean pine forest and alpine tundra zone..展开更多
Twenty plots were investigated on northern slope of Changbai Mountain at an attitude interval of 100 m (from 700 to 2600 m). The species co-possession between plant communities at different altitudes was analyzed by J...Twenty plots were investigated on northern slope of Changbai Mountain at an attitude interval of 100 m (from 700 to 2600 m). The species co-possession between plant communities at different altitudes was analyzed by Jaccard index. The analytical results showed that the co-possession calculated according to species in different layers or all species between adjacent communities was higher than that between disjunct communities. The co-possessions between adjacent communities calculated by species in different layers had comparability and dissimilarity. If the two adjacent communities belong to different types of vegetation, then their co-possession was lower. The peak values and valley values of species co-possession between communities along elevation gradient just matched vegetation gradient patterns, and species subrogation of shrubs had more obvious rule on northern slope of Changbai Mountain. Co-possessions between communities with same altitude difference were much similar, and it decreased as the increase of elevation difference, which showed that species compositions in different layers of the communities were highly related.展开更多
The main factors affecting seismic exploration is the propagation velocity of seismic waves in the medium. In the past, during marine seismic data processing, the propagation velocity of sea water was generally taken ...The main factors affecting seismic exploration is the propagation velocity of seismic waves in the medium. In the past, during marine seismic data processing, the propagation velocity of sea water was generally taken as a constant 1500 m/s. However, for deep water exploration, the sound velocity varies with the season, time, location, water depth, ocean currents, and etc.. It also results in a layered velocity distribution, so there is a difference of seismic traveltime, ray paths, and amplitude, which affect the migration imaging results if sea water propagation velocity is still taken as constant for the propagation wavefield. In this paper, we will start from an empirical equation of seismic wave velocity in seawater with changes of temperature, salinity, and depth, consider the variation of their values, build a seawater velocity model, and quantitatively analyze the impact of seawater velocity variation on seismic traveltime, ray paths, and amplitude in the seawater velocity model.展开更多
Based on analyzing the limit of Ziolkowski's bubble oscillation formulation,a new model with various physical factors is established to simulate air gun signatures fo marine seismic exploration.The practical effects ...Based on analyzing the limit of Ziolkowski's bubble oscillation formulation,a new model with various physical factors is established to simulate air gun signatures fo marine seismic exploration.The practical effects of physical factors,such as heat transfe across the bubble wall,air gun port throttling,vertical rise of the bubble,fluid viscosity,and the existence of the air gun body were all taken into account in the new model.Compared with Ziolkowski's model,the signatures simulated by the new model,with small peak amplitude and rapid decay of bubble oscillation,are more consistent with actual signatures The experiment analysis indicates:(1)gun port throttling controls the peak amplitude of ai gun pulse;(2)since the hydrostatic pressure decreases when the bubble rises,the bubble oscillation period changes;(3)heat transfer and fluid viscosity are the main factors tha explain the bubble oscillation damping.展开更多
Fourteen plots were chosen along with the altitude of 1600-2600 m in Guandi Mountain, Shanxi Province, China to investigate all the trees in the plots, and the species diversity indexes were calculated for analyzing t...Fourteen plots were chosen along with the altitude of 1600-2600 m in Guandi Mountain, Shanxi Province, China to investigate all the trees in the plots, and the species diversity indexes were calculated for analyzing the effects of altitudinal gradient on plant species diversity. The results showed that the order of dominant species from low altitude to high altitude is as Quercus liaotungensis Koidz, Pinus tabulaeformis, Betula platyphylla, B. albo-sinensis, Picea wilsonii, P. Meyeri and Larix principis-rupprechtii. With altitude increasing, the average height and DBH of the arbor firstly increase and then decrease, the maximal height and DBH of the arbor present the unimodal variable trend, the maximal height of coniferous and broad-leaved trees firstly increases and then decreases, the maximal DBH of broad-leaf trees has no clear fluctuation, and the maximal DBH of the needle-leaf trees decreases gradually. Moreover, in middle altitudinal communities (the altitude of 1900-2200 m), the maximal height and DBH of the needle-leaf trees are larger than these of broad-leaf trees. Both Shannon-wiener index and Margalef index of the communities present the unimodal variable trend, with a peak in the mid-altitude. Plant species diversity in the mid-altitude (1900-2200 m) is higher than that of the low altitude (1600-1900 m) and the high altitude (2200-2600 m). In addition, the unimodal variable trend of α species diversity is clearly correlated with the altitudinal gradient. The change of plant species diversity is significantly correlated with the altitudinal gradient, and also related to the community structure, the community composition, the feature of species and the human disturbance.展开更多
XCTD, as one of the most important instruments for the deep sea exploration, is an important device for deep-sea hydrological data acquisition. But some difficult technical problems of traditional metal enameled wire ...XCTD, as one of the most important instruments for the deep sea exploration, is an important device for deep-sea hydrological data acquisition. But some difficult technical problems of traditional metal enameled wire channel have become the major bottleneck for XCTD development. Aiming at this problem, this paper puts forward with using single-mode fiber as the transmission channel of XCTD. Firstly, this paper makes a brief analysis on the problems of using enameled wire as transmission channel faces. Secondly, it analyzes the advantages of the single mode fiber technology. Finally, it makes theoretical research and experimental verification of the influence of seawater temperature change on the optical fiber transmission channel. The experimentat results show that the error rate at the transmission rate of 10 MB/S is 0, and the loss can be negligible when the single-mode fiber channel is used in the sea water and the seawater temperature changes from 0 to 20℃. This method will greatly increase the rate of signal transmission and the transmission stability. And this paper shows that using the single-mode fiber as the transmission channel of XCTD has certain feasibility.展开更多
[Objective] The aim of this study is to investigate species diversity of alpine vegetation in different altitudes of Daban mountain. [Method] Plant communities were surveyed in three different altitudes (3 025 m,3 40...[Objective] The aim of this study is to investigate species diversity of alpine vegetation in different altitudes of Daban mountain. [Method] Plant communities were surveyed in three different altitudes (3 025 m,3 405 m,3 813 m) of Daban mountain,the eastern Qilian,and the richness or diversity index of vegetation in three different altitudes was comparatively analyzed. [Result] The species richness decreased with the gradual increase of altitude,and species diversity of plant communities was relatively lower in medium altitude. Furthermore,community similarity also decreased with the increase of altitude,and β diversity of communities had a significant change. [Conclusion] Environmental factor change caused by different altitudes and human disturbance are important reasons for the change of species distribution pattern in different altitudes.展开更多
A Hybrid Coordinate Ocean Model (HYCOM) is used to simulate the sea surface temperature of the Tropical and North Pacific. Based on the different combinations of two air-Sea flux data sets (COADS and ECMWF) and tw...A Hybrid Coordinate Ocean Model (HYCOM) is used to simulate the sea surface temperature of the Tropical and North Pacific. Based on the different combinations of two air-Sea flux data sets (COADS and ECMWF) and two bulk parameter formulas (non-constant and constant), four numerical experiments are carried out. The following conclusions can be deduced from the numerical results. (1) The numerical results using non-constant bulk parameter formula are much better than those using constant one. In the Pacific area from 40°N to 20°S, the annual average SST obtained from the experiment using non-constant bulk parameter formula is 0.21 ℃ higher than that from the satellite-based SST climatology (the pathfinder data). However, the difference is 0.63 ℃ for the experiment when the using constant one. (2) HYCOM successfully simulates the monthly variation of climatological SST in tropical and north Pacific basins and monthly spatial variation of Western Pacific Warm Pool. Especially in the Pacific area from 40°N to 20°S, the difference of the seasonal averaged SST between pathfinder data and the result of experiment 2 (using COADS data set and non-constant bulk parameter formula) is only about 0.02 ℃. (3)The simulation results using different Air-Sea flux data are different and the difference is very large in some regions. In the northwest of the model region, the annual average SST obtained from experiment 2 (using COADS data set) is 1℃ higher than that obtained from experiment 4 (using ECMWF data set). Contrarily, the result of experiment 4 is 1 ℃ larger than that of experiment 2 in the southeast of the model region. The largest difference is about 4 ℃ occurred near the area of 58°N, 140°E and the Bohai sea.展开更多
The basic principles of sea surface temperature (SST) remote sensing using infrared and microwave radiometers are introduced, and the differences between two sensors for retrieving sea surface temperature are invest...The basic principles of sea surface temperature (SST) remote sensing using infrared and microwave radiometers are introduced, and the differences between two sensors for retrieving sea surface temperature are investigated. The ground resolution, atmospheric effect, sea surface wind, skin depth and so on have important influence on precision of sea surface temperature retrieved by two sensors. The better understanding of the advantage and disadvantage of sea surface temperature detected by infrared and microwave radiometers would help us to imply SST remote sensing data more effectively and correctly.展开更多
Igneous rocks in the South China Sea have broad prospects for oil and gas exploration.Integrated geophysical methods are important approaches to study the distribution of igneous rocks and to determine and identify ig...Igneous rocks in the South China Sea have broad prospects for oil and gas exploration.Integrated geophysical methods are important approaches to study the distribution of igneous rocks and to determine and identify igneous rock bodies.Aimed at the characteristics of gravity and magnetic fields in the South China Sea,several potential field processing methods are preferentially selected.Reduction to the pole by variable inclinations in the area of low magnetic latitudes is used to perform reduction processing on magnetic anomalies.The preferential continuation method is used to separate gravity and magnetic anomalies and extract the gravity and magnetic anomaly information of igneous rocks in the shallow part of the South China Sea.The 3D spatial equivalent distribution of igneous rocks in South China Sea is illustrated by the 3 D correlation imaging of magnetic anomalies.Since the local anomaly boundaries are highlighted gravity and magnetic gradients,the distribution characters of different igneous rocks are roughly outlined by gravity and magnetic correlation analysis weighted by gradient.The results show the distribution of igneous rocks is controlled and influenced by deep crustal structure and faulting.展开更多
This paper introduces the design and implementation of sea-water temperature auto-monitoring system based on General Packet Radio Service (GPRS). This system integrates modern wireless communication technology, the ...This paper introduces the design and implementation of sea-water temperature auto-monitoring system based on General Packet Radio Service (GPRS). This system integrates modern wireless communication technology, the signal gathering technology and computer network technology. MSC1210 microcontroller is used in data collection device in order to make system accurate and fast. In addition, wireless and Internet technologies are used for transferring and displaying collected field data. A prototype system has been completed and tested in field trials. The results proved the feasibility and usefulness of this system for monitoring the temperature. By using this system, a lot of resources and money can be saved.展开更多
For open sea conditions the sea surface roughness is described as a function of surface stress and wind speed over sea surface by Charnock relation. The sea surface roughnessn in the North-west Pacific Ocean is derive...For open sea conditions the sea surface roughness is described as a function of surface stress and wind speed over sea surface by Charnock relation. The sea surface roughnessn in the North-west Pacific Ocean is derived successfully using wind speed data estimated by the TOPEX satellite altimeter. From the results we find that: (1) the mean sea surface roughness in winter is greater than in summer; (2) compared with other sea areas, the sea surface roughness in the sea area east of Japan ( N30°- 40°, E135°- 150°) is larger than in other sea areas; (3) sea surface roughness in the South China Sea changes more greatly than that in the Bohai Sea, Yellow Sea and East China Sea.展开更多
基金973 Project (G1999043407-1) and Project for pioneering new knowledge from Chinese Academy of Sciences (KZCX2-406-1-3).
文摘In order to decipher phenomenon of tree line changing with climate variety, the trend of tree line on the northern slope of Changbai Mountain was studied. Based on the meteorological data of Changbai Mountain, the January temperature (the limiting effect for tree line) and annual mean temperature were mainly investigated. In the ecotone between Betula ermanii and alpine tundra, the number and diameter at ground level of Betula ermanii in the plots were measured. According to the correlation between diameter at ground level (DGL) and age, the diameter at ground level can represent age directly. The results showed that the distribution age of Betula ermanii was in the trend of decreasing with elevation rising. In resent years, the annual mean temperature near Changbai Mountain is rising, which has led to the tree line ascending.
基金supported by the Chinese Academy of Science(grand KZCX2-406)founded by Chinese Science of Academy undred People’Project.
文摘By the method of gradient pattern analysis, twenty plots were set at altitudes of 700-2600 m with an interval of 100 m on the northern slope of the Changbai Mountain. The dissimilarity of respective sub-plots in the same community was measured and the complexity of plant communities at different altitudes was analyzed. The result from binary data of tree species in canopy tree indicated that the sub-plots in the communities, except subalpine Betula ermanii forest, showed comparatively high dissimilarity in species composition. Especially, the dissimilarity index (0.7) of broadleaved/Korean pine forest at low altitudes was obviously higher than other communities. The differences are not obvious between communities referring to dark coniferous forest. Comparatively, the dissimilarity in sub-plots of the communities at altitude of 1400 m was slightly higher than that of other communities, which reflected the complexity of tree species compositions of transitory-type communities. For subalpine Betula ermanii forest, tree species composition was simple and showed a high similarity between sub-plots. The results derived from binary data of shrub showed that the dissimilarity index of shrub species in broadleaved/Korean pine forest at low altitudes was higher than that in other communities, but the divergence tendency wasn抰 so obvious as that of arbor species. The dissimilarity derived from binary data of herb and all plant species at different altitudes showed greatly close tendency, and the differences in herb and all plant species between sub-plots were the greatest for the communities of broad-leaved-Korean pine forest and alpine tundra zone..
基金the Chinese Academy of Science (a grant KZCX2-406), National Natural Science Foundation of China (NSFC39970123), and Changbai Mo
文摘Twenty plots were investigated on northern slope of Changbai Mountain at an attitude interval of 100 m (from 700 to 2600 m). The species co-possession between plant communities at different altitudes was analyzed by Jaccard index. The analytical results showed that the co-possession calculated according to species in different layers or all species between adjacent communities was higher than that between disjunct communities. The co-possessions between adjacent communities calculated by species in different layers had comparability and dissimilarity. If the two adjacent communities belong to different types of vegetation, then their co-possession was lower. The peak values and valley values of species co-possession between communities along elevation gradient just matched vegetation gradient patterns, and species subrogation of shrubs had more obvious rule on northern slope of Changbai Mountain. Co-possessions between communities with same altitude difference were much similar, and it decreased as the increase of elevation difference, which showed that species compositions in different layers of the communities were highly related.
基金supported by the Major Projects of National Science and Technology Sub-topics(2011ZX05025-001-05)
文摘The main factors affecting seismic exploration is the propagation velocity of seismic waves in the medium. In the past, during marine seismic data processing, the propagation velocity of sea water was generally taken as a constant 1500 m/s. However, for deep water exploration, the sound velocity varies with the season, time, location, water depth, ocean currents, and etc.. It also results in a layered velocity distribution, so there is a difference of seismic traveltime, ray paths, and amplitude, which affect the migration imaging results if sea water propagation velocity is still taken as constant for the propagation wavefield. In this paper, we will start from an empirical equation of seismic wave velocity in seawater with changes of temperature, salinity, and depth, consider the variation of their values, build a seawater velocity model, and quantitatively analyze the impact of seawater velocity variation on seismic traveltime, ray paths, and amplitude in the seawater velocity model.
基金supported by the National 973 Program(Grant No.2007CB209608)National 863 Program(Grant No.2007AA06Z218)
文摘Based on analyzing the limit of Ziolkowski's bubble oscillation formulation,a new model with various physical factors is established to simulate air gun signatures fo marine seismic exploration.The practical effects of physical factors,such as heat transfe across the bubble wall,air gun port throttling,vertical rise of the bubble,fluid viscosity,and the existence of the air gun body were all taken into account in the new model.Compared with Ziolkowski's model,the signatures simulated by the new model,with small peak amplitude and rapid decay of bubble oscillation,are more consistent with actual signatures The experiment analysis indicates:(1)gun port throttling controls the peak amplitude of ai gun pulse;(2)since the hydrostatic pressure decreases when the bubble rises,the bubble oscillation period changes;(3)heat transfer and fluid viscosity are the main factors tha explain the bubble oscillation damping.
基金This paper was supported by Shanxi Natural Science Foun-dation (20001090)
文摘Fourteen plots were chosen along with the altitude of 1600-2600 m in Guandi Mountain, Shanxi Province, China to investigate all the trees in the plots, and the species diversity indexes were calculated for analyzing the effects of altitudinal gradient on plant species diversity. The results showed that the order of dominant species from low altitude to high altitude is as Quercus liaotungensis Koidz, Pinus tabulaeformis, Betula platyphylla, B. albo-sinensis, Picea wilsonii, P. Meyeri and Larix principis-rupprechtii. With altitude increasing, the average height and DBH of the arbor firstly increase and then decrease, the maximal height and DBH of the arbor present the unimodal variable trend, the maximal height of coniferous and broad-leaved trees firstly increases and then decreases, the maximal DBH of broad-leaf trees has no clear fluctuation, and the maximal DBH of the needle-leaf trees decreases gradually. Moreover, in middle altitudinal communities (the altitude of 1900-2200 m), the maximal height and DBH of the needle-leaf trees are larger than these of broad-leaf trees. Both Shannon-wiener index and Margalef index of the communities present the unimodal variable trend, with a peak in the mid-altitude. Plant species diversity in the mid-altitude (1900-2200 m) is higher than that of the low altitude (1600-1900 m) and the high altitude (2200-2600 m). In addition, the unimodal variable trend of α species diversity is clearly correlated with the altitudinal gradient. The change of plant species diversity is significantly correlated with the altitudinal gradient, and also related to the community structure, the community composition, the feature of species and the human disturbance.
基金supported by the Research Program of Application Foundation and Advanced Technology of Tianjin (No. 14JCYBJC16300)the National Natural Science Foundation of China (No. 41206031)
文摘XCTD, as one of the most important instruments for the deep sea exploration, is an important device for deep-sea hydrological data acquisition. But some difficult technical problems of traditional metal enameled wire channel have become the major bottleneck for XCTD development. Aiming at this problem, this paper puts forward with using single-mode fiber as the transmission channel of XCTD. Firstly, this paper makes a brief analysis on the problems of using enameled wire as transmission channel faces. Secondly, it analyzes the advantages of the single mode fiber technology. Finally, it makes theoretical research and experimental verification of the influence of seawater temperature change on the optical fiber transmission channel. The experimentat results show that the error rate at the transmission rate of 10 MB/S is 0, and the loss can be negligible when the single-mode fiber channel is used in the sea water and the seawater temperature changes from 0 to 20℃. This method will greatly increase the rate of signal transmission and the transmission stability. And this paper shows that using the single-mode fiber as the transmission channel of XCTD has certain feasibility.
基金Supported by National Sci-tech Support Plan (2007BAC03A08-5)National Natural Science Foundation ( N0. 30570300, 30590381-02)The Third Period of 211 Project of Innovation Personnel Training for Postgraduate Education in Minzu University of China(0212110309090209)~~
文摘[Objective] The aim of this study is to investigate species diversity of alpine vegetation in different altitudes of Daban mountain. [Method] Plant communities were surveyed in three different altitudes (3 025 m,3 405 m,3 813 m) of Daban mountain,the eastern Qilian,and the richness or diversity index of vegetation in three different altitudes was comparatively analyzed. [Result] The species richness decreased with the gradual increase of altitude,and species diversity of plant communities was relatively lower in medium altitude. Furthermore,community similarity also decreased with the increase of altitude,and β diversity of communities had a significant change. [Conclusion] Environmental factor change caused by different altitudes and human disturbance are important reasons for the change of species distribution pattern in different altitudes.
文摘A Hybrid Coordinate Ocean Model (HYCOM) is used to simulate the sea surface temperature of the Tropical and North Pacific. Based on the different combinations of two air-Sea flux data sets (COADS and ECMWF) and two bulk parameter formulas (non-constant and constant), four numerical experiments are carried out. The following conclusions can be deduced from the numerical results. (1) The numerical results using non-constant bulk parameter formula are much better than those using constant one. In the Pacific area from 40°N to 20°S, the annual average SST obtained from the experiment using non-constant bulk parameter formula is 0.21 ℃ higher than that from the satellite-based SST climatology (the pathfinder data). However, the difference is 0.63 ℃ for the experiment when the using constant one. (2) HYCOM successfully simulates the monthly variation of climatological SST in tropical and north Pacific basins and monthly spatial variation of Western Pacific Warm Pool. Especially in the Pacific area from 40°N to 20°S, the difference of the seasonal averaged SST between pathfinder data and the result of experiment 2 (using COADS data set and non-constant bulk parameter formula) is only about 0.02 ℃. (3)The simulation results using different Air-Sea flux data are different and the difference is very large in some regions. In the northwest of the model region, the annual average SST obtained from experiment 2 (using COADS data set) is 1℃ higher than that obtained from experiment 4 (using ECMWF data set). Contrarily, the result of experiment 4 is 1 ℃ larger than that of experiment 2 in the southeast of the model region. The largest difference is about 4 ℃ occurred near the area of 58°N, 140°E and the Bohai sea.
文摘The basic principles of sea surface temperature (SST) remote sensing using infrared and microwave radiometers are introduced, and the differences between two sensors for retrieving sea surface temperature are investigated. The ground resolution, atmospheric effect, sea surface wind, skin depth and so on have important influence on precision of sea surface temperature retrieved by two sensors. The better understanding of the advantage and disadvantage of sea surface temperature detected by infrared and microwave radiometers would help us to imply SST remote sensing data more effectively and correctly.
基金the National 863 Projects(Nos.2006AA06Z111,2006AA06201-3,and 2006AA09A101-3)National Special Project(No.SinoProbe-01-05)Open Project of the National Key Laboratory for Geological Processes and Mineral Resources(No.GPMR0942).
文摘Igneous rocks in the South China Sea have broad prospects for oil and gas exploration.Integrated geophysical methods are important approaches to study the distribution of igneous rocks and to determine and identify igneous rock bodies.Aimed at the characteristics of gravity and magnetic fields in the South China Sea,several potential field processing methods are preferentially selected.Reduction to the pole by variable inclinations in the area of low magnetic latitudes is used to perform reduction processing on magnetic anomalies.The preferential continuation method is used to separate gravity and magnetic anomalies and extract the gravity and magnetic anomaly information of igneous rocks in the shallow part of the South China Sea.The 3D spatial equivalent distribution of igneous rocks in South China Sea is illustrated by the 3 D correlation imaging of magnetic anomalies.Since the local anomaly boundaries are highlighted gravity and magnetic gradients,the distribution characters of different igneous rocks are roughly outlined by gravity and magnetic correlation analysis weighted by gradient.The results show the distribution of igneous rocks is controlled and influenced by deep crustal structure and faulting.
文摘This paper introduces the design and implementation of sea-water temperature auto-monitoring system based on General Packet Radio Service (GPRS). This system integrates modern wireless communication technology, the signal gathering technology and computer network technology. MSC1210 microcontroller is used in data collection device in order to make system accurate and fast. In addition, wireless and Internet technologies are used for transferring and displaying collected field data. A prototype system has been completed and tested in field trials. The results proved the feasibility and usefulness of this system for monitoring the temperature. By using this system, a lot of resources and money can be saved.
文摘For open sea conditions the sea surface roughness is described as a function of surface stress and wind speed over sea surface by Charnock relation. The sea surface roughnessn in the North-west Pacific Ocean is derived successfully using wind speed data estimated by the TOPEX satellite altimeter. From the results we find that: (1) the mean sea surface roughness in winter is greater than in summer; (2) compared with other sea areas, the sea surface roughness in the sea area east of Japan ( N30°- 40°, E135°- 150°) is larger than in other sea areas; (3) sea surface roughness in the South China Sea changes more greatly than that in the Bohai Sea, Yellow Sea and East China Sea.