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    30 June 2010, Volume 22 Issue 2 Previous Issue    Next Issue

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    CALCULATION OF PHOTOSYNTHETICALLY AVAILABLE RADIATION USING MULTISPECTRAL DATA IN THE ARCTIC
    2010, 22 (2-Chinese):  91-103.  DOI: 10.3724/SP.J.1084.2010.00091
    Abstract ( 1758 )   PDF (604KB) ( 1475 )  
    Photosynthetically Available Radiation (PAR) is an important bio-optical parameter related to marine primary production. PAR is usually measured by a single band sensor and can also be calculated by multispectral data. When the PAR is calculated by multispectral data in polar region, four factors are possible error sources. PAR could be overestimated as the wavelengths of multispectral instrument are usually chosen to evade main absorption zones of atmosphere. However, both PARs calculated by hyperspectral and multispectral data are consistent with the error less than 1%. By the fitting function proposed here, the PAR calculated by multispectral data has the same accuracy with that by hyperspectral data. To calculate the attenuation rate of the PAR needs PAR0, the PAR just under the surface. Here, an approach is proposed to calculate PAR0 by the best fit of the irradiance profile of 1-5 m with a content attenuation coefficient under surface. It is demonstrated by theory and data observed in different time at same location that the attenuation coefficient of PAR is independent of the intensity of radiation. But under sea ice, the attenuation coefficient of PAR is little bit different, as the spectrum of the light has been changed by selective absorption through the sea ice. Therefore, the difference of inclusions inside sea ice will result in different PAR, and impact the attenuation of PAR. By the results of this paper, PAR can be calculated reliably by multispectral data.
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    Features of Northwest Passage Sea Ice’s Distribution and Variation under Arctic Rapidly Warming Condition
    2010, 22 (2-Chinese):  104-124.  DOI: 10.3724/SP.J.1084.2010.00104
    Abstract ( 2248 )   PDF (19232KB) ( 1691 )  

    Recently, rapid warming of the Arctic has made it possible for the Northwest Passage navigation. In this paper, we studied the characters of variation of sea ice concentration around the Northwest Passage using AMSR-E sea ice concentration product with the resolution of 6.25 kilometers from the year 2002 to 2008. By analysis melting period, ice-free period, slight-ice period, ice-free days, slight-ice days, as well as some details of the variation and distribution of sea ice in main ice-block area along the passages, We got deeper understanding of the main features of sea ice seasonal and interannual variation and distribution, especially the information related to Northwest Passage’s navigation possibility. Our research shows that south route is easier to navigate than north route of Northwest Passage. The existing time period of ice-blocking part of each route represents a decreasing trend, while ice-free and light ice dates show a increasing trend. The variation and distribution of polynya and Circumpolar Flaw Lead might effect the beginning time of sea ice melting of the whole passage in great extent.

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    Distribution and abundance of euphausiid larve and salps during austral summers in Prydz Bay, Antarctica
    2010, 22 (2-Chinese):  125-134.  DOI: 10.3724/SP.J.1084.2010.00125
    Abstract ( 1996 )   PDF (1140KB) ( 1510 )  

    The distribution and abundance of euphausiid larvae and salps were studied based on zooplankton samples collected in 2002 and 2006 from Prydz Bay, Antarctic. Larvaes of Thysanoessa macrura and Euphausia superba mainly distributed in the north of the continental shelf. Thysanoessa macrura was more abundant with relatively wider distribution area. In the year 2006 with earlier ice retreating, higher seawater temperature and chlorophyll a level, Euphausia superba and Thysanoessa macrura presented higher abundance and older developmental stage. Euphausia crystallorophias was mainly distributed in the neritic region. In the year 2002 with serious ice conditions in the neritic region, the abundance of Euphausia crystallorophias was only 95.6ind/1000m3. In the year 2006 when polynya existed, the abundance of Euphausia crystallorophias reached to 43966.6ind/1000m3, and the population was mainly composed of metanauplius (MN) and calyptopis I (CI). Salps, mostly composed of Salpa thompsoni, had a low abundance in the Prydz Bay. In 2002, S. thompsoni was only found at one station of the north of the bay with the abundance 10ind/1000m3. In 2006, S. thompsoni was found at three stations located near continental slope and average abundance reached to 146.7ind/1000m3. The research suggested that the distribution and abundance of euphausiid larvae and salps have good accordance with the environmental factors.

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    A PRELIMINARY STUDY OF SELENIUM AND MINERAL ELEMENTS IN ANTARCTIC KRILL
    2010, 22 (2-Chinese):  135-140.  DOI: 10.3724/SP.J.1084.2010.00135
    Abstract ( 1983 )   PDF (318KB) ( 2167 )  

    The contents of selenium and mineral elements in Antarctic krill and domestic shrimp were determined by hydride generation  atomic fluorescence spectrometry (HG-AFS) and inductively coupled plasma atomic emission spectrometry (ICP-AES), respectively. The results showed that Antarctic krill selenium content ranged from 2.48 to 4.15 mg/kg (average value: 3.32±0.73), which was 2—5 times higher than that in domestic shrimps. Meanwhile, the Antarctic krill P, Mg, and Zn was 14.31±0.45 mg/g, 6.18±0.16 mg/g and 153.9±5.7 mg/kg, respectively, which was approximately 1.5 time higher than that in domestic shrimps. Additionally, the Antarctic krill arsenic content ranged from 0.68 to 1.22 mg/kg, which was significantly lower than the national arsenic content standard GB4810-94 for seafood (≦2.0 mg/kg, as inorganic arsenic). The results revealed that Antarctic krill is not only a good food source of selenium and some other mineral elements, but also can be used as the raw materials of aquaculture feedstuff selenium additives and seleniumenriched food additives for the residents in selenium deficiency areas.

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    A CASE STUDY ON BLIZZARD WEATHER AT GREAT WALL STATION,ANTARCTICA
    2010, 22 (2-Chinese):  141-149.  DOI: 10.3724/SP.J.1084.2010.00141
    Abstract ( 1950 )   PDF (7798KB) ( 1273 )  

    A blizzard case at Great Wall Station was studied using data of NCEP analysis, in-site observations, surface weather charts and statellite images. The blizzard weather took place on August 29th,2006, and resulted in highest wind speed (33.3m/s) and the worst horizontal visibility (<10m). It’s found that this blizzard was under the situation of ‘High in the south, low in the north’, and the easterly gale caused by the weather situation was the precondition to the blizzard occur. The low level easterly jet from the Antarctic continent brought significiant decrease in air temperature and humidity, made the blizzard with obvious feature of low temperature and humidity. The warm air advection at high levels brought enough mositure from lower latitudes. The deep cyclonic vorticity at middle and low level, the pattern of divergence at high level and convergence at low level, and strong vertical uplifts were the dynamic reason of the strong snowfall and blizzard. There was a inversion layer in the low atmospheric level during the later half of the case which essential was the air mass vertical structure of “cold at low level, warm at high level”, it’s very important to the lasting of the blizzard.

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    Atmospheric Numerical Analyses over Arctic Region during the period of typical months
    2010, 22 (2-Chinese):  150-163.  DOI: 10.3724/SP.J.1084.2010.00150
    Abstract ( 1780 )   PDF (10495KB) ( 1267 )  

    The modeled atmospheric circulations around the Arctic region during the period of 17-19, July, 2005 and 20-24, December, 2007 with the Polar MM5 are presented, respectively. The numerical analyses indicated there were two fluctuation modes existed over the Pole both in summer and winter season. There was an Iceland low additionally in summer simulation instead of a high pressure system existed around the Iceland in winter. And this high pressure system extended to the Greenland. Two upper-air observations from the Arctic are used to verify the simulated atmospheric state for the variables of temperature and wind. The model is found to reproduce the observed atmospheric state with smaller biases and larger correlation coefficients for the variables considered. Moreover, the mesoscale model reflected evident diurnal cycles for the temperature at height of 2m, sensible heat and latent heat fluxes at station Barrow in July; and the inversed temperature at Barrow was also simulated by the model, effectively. In winter, T2m and turbulent fluxes took on the characteristics of anti-phase state. The Arctic landuse was the heat and moisture source of the atmosphere, although the amplitude of fluxes in winter was far less than the state of summer.

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    The physiological and biochemical responses of an Arctic microalgae (Chlorella sp.) to UV-B radiation
    2010, 22 (2-Chinese):  164-173.  DOI: 10.3724/SP.J.1084.2010.00164
    Abstract ( 1862 )   PDF (493KB) ( 1517 )  

    The response of an Arctic microalgae strain (Chlorella sp.) to the enhancement of UV-B radiation was explored in this paper. The effects of three different intensity (0 μw/cm2, 45 μw/cm2, 76 μw/cm2 ) within 12 h radiation following with 4 h non-radiation recovery were studied, while the biochemical components were tested by sampling every 4 h. Our results showed that: (1) Under the lower intensity of UV-B (45μw/cm2) radiation, Chla and Car content increased in the beginning 4 h and then decreased. The maximum value presented after 4 hrs. Meanwhile, under high-intensity UV-B (76μw/cm2) radiation, Chla and CAR content constantly decreased. (2) The content of O2?ˉ and MDA enhanced along with radiation time and intensity. Moreover, H2O2 content also increased with irradiation time; significant vary happened after 8 h radiation. (3) SOD, CAT activity under the lower UV-B treatment, increased with irradiation time as well. Under higher UV-B radiation, SOD activity increased at the beginning 4 hrs and then decreased constantly, CAT activity fluctuated from time to time.(4)The fatty acid composition of Chlorella was influenced. The results supported that UV-B had adverse effects on the Arctic glaciers microalgae, and the effect of hurt was more significant under high-intensity or high doses of UV-B.

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    Current Situation of Antactic Research Work based on the Collection and Analysis of Antarctic Research Articles
    2010, 22 (2-Chinese):  174-189.  DOI: 10.3724/SP.J.1084.2010.00174
    Abstract ( 1447 )   PDF (2375KB) ( 1643 )  

    Based on almost all the articles on Antarctic study during 1999-2008 covered in WOS database, which amounts to 25345, this paper focused on the analysis to those articles from the aspects of the cooperative degree, author organizations and the authors with analysis tools of h-index, g-index, cited paper number and Social Network graphics, to see the current situation and development trend of Antarctic research.

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    RESEARCH ON NON-METRIC DIGITAL AERIAL PHOTOGRAMMETRY TECHNOLOGY BASED ON HELICOPTER IN ANTARCTICA
    2010, 22 (2-Chinese):  190-198.  DOI: 10.3724/SP.J.1084.2010.00190
    Abstract ( 1480 )   PDF (3482KB) ( 1916 )  

    This paper introduced the overall flowchart of photogrammetry for Zhongshan Station and Larsemann Hills area in Antarctica using Hasselblad H1D non-metric digital camera by taking helicopter as the platform. Through the calibration of non-metric digital camera, it acquired the interior orientation elements for implementing the aerial photogrammtry. Taking the practical experiments for two areas as example, the results showed that the aerial photogrammetry using non-metric digital camera based on helicopter can be applied for topographic mapping in Antarctica and other remote areas.

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    THE ROUTE SELECTION FOR R/V XUELONG’S CROSSING THE WESTERLY BELT BASED ON THE 25TH CHINESE NATIONAL ANTARCTIC RESEARCH EXPEDITION
    2010, 22 (2-Chinese):  199-210.  DOI: 10.3724/SP.J.1084.2010.00199
    Abstract ( 1586 )   PDF (3457KB) ( 1586 )  

    The most dangerous section of the Antarctic voyage is crossing the Westerly Belt. It is of great significance to select the right route for the safety of the scientific research Navigation according to the weather of the Westerly Belt. R/V Xuelong had crossed the Westerly Belt four times during the 25th Chinese National Antarctic Research Expedition( CHINARE2008—2009). Based on the data of this navigation and the past experience, The weather and route selection in the Westerly Belt is analyzed, and the weather Situation and route selection in the South-East Indian Ocean is studied. The main conclusions are:(1)the key to ship weather routing in the Westerly Belt is making correct Analysis and forecasting about the cyclone development and movement; (2)the weather Situation of South-East Indian Ocean can be summarized as three kinds of weather pattern, Namely zonal type(flat type),high-pressure ridge type and trough frontage type. The high-pressure ridge type is suitable for crossing, the trough frontage type is not Suitable for crossing, the zonal type lies in between; (3)there are two navigation methods of crossing the Westerly Belt, namely customary route and the north-south vertical route. The vertical route is suitable to forward voyage, but has relative limitation for the return voyage. (4)In the actual voyage, the route should be selected based on the actual route features, weather situation and other factors.

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