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1.
在数值预报中应用卫星反演资料的质量控制研究   总被引：2，自引：1，他引：2  
资料变分同化作为提高数值预报准确率的有效手段之一，受到了越来越多的关注。如何将分辨率较高的卫星资料应用到数值预报中，弥补常规观测网时空分辨率的不足，成为数值天气预报的重要课题。以1996年6月28-29日发生在江淮流域的暴雨过程为例，依据其中尺度场和能量场特征，分别以低云量、急流、湿静力能为标准设计了三套质量控制方案。将质量控制后的反演湿度场变分同化并应用到中尺度MM5模式中，结果表明：经质量控制后，可以明显地改善降水区域及降水量的预报；对降水预报，特别是强降水天气过程的预报，该质量控制方案具有普遍意义。  相似文献   
2.
Dammam City is one of the gorgeous coastal areas in the Arabian Gulf of Saudi Arabia.The present study aimed to ex-amine one of the copepod species infecting the rosy goatfish that represents a highly consumed fish species by the local population in the Arabian Gulf.The copepod species isolated from the infected fish specimens belong to the family Taeniacanthidae and was iden-tified as Irodes parupenei Ho and Lin(2007),primarily based on its morphological,morphometric,and ultrastructural characteris-tics,especially the structures of the dorsal cephalic area,segmentation of the first antenna,the absence of the maxilliped claw in the fe-male specimens,and the setation and spinulation of the legs 2-4 for the adult females are of great significance in the taxonomic iden-tification.The 18S rRNA gene sequence was analyzed to ensure the precise identity and exact taxonomic status of the copepod species.The result showed that this copepod species belong to Taenicanthidae and closely related to Irodes sauridi(gb|JF781550.1)in the same taxon.More details on the specificity of the goatfish for Irodes species and identifying these parasitic taxa using molecular analysis are given in the present study.  相似文献   
3.
Determination of the peak thermal condition is vital in order to understand tectono-thermal evolution of the Himalayan belt. The Lesser Himalayan Sequence (LHS) in the Western Arunachal Pradesh, being rich in carbonaceous material (CM), facilitates the determination of peak metamorphic temperature based on Raman spectroscopy of carbonaceous material (RSCM). In this study, we have used RSCM method of Beyssac et al. (J Metamorph Geol 20:859–871, 2002a) and Rahl et al. (Earth Planet Sci Lett 240:339–354, 2005) to estimate the thermal history of LHS and Siwalik foreland from the western Arunachal Pradesh. The study indicates that the temperature of 700–800 °C in the Greater Himalayan Sequence (GHS) decreases to 650–700 °C in the main central thrust zone (MCTZ) and decreases further to <200 °C in the Mio-Pliocene sequence of Siwaliks. The work demonstrates greater reliability of Rahl et al.’s (Earth Planet Sci Lett 240:339–354, 2005) RSCM method for temperatures >600 and <340 °C. We show that the higher and lower zones of Bomdila Gneiss (BG) experienced temperature of ~600 °C and exhumed at different stages along the Bomdila Thrust (BT) and Upper Main Boundary Thrust (U.MBT). Pyrolysis analysis of the CM together with the Fission Track ages from upper Siwaliks corroborates the RSCM thermometry estimate of ~240 °C. The results indicate that the Permian sequence north of Lower MBT was deposited at greater depths (>12 km) than the upper Siwalik sediments to its south at depths <8 km before they were exhumed. The 40Ar/39Ar ages suggest that the upper zones of Se La evolved ~13–15 Ma. The middle zone exhumed at ~11 Ma and lower zone close to ~8 Ma indicating erosional unroofing of the MCT sheet. The footwall of MCTZ cooled between 6 and 8 Ma. Analyses of P–T path imply that LHS between MCT and U.MBT zone falls within the kyanite stability field with near isobaric condition. At higher structural level, the temperatures increase gradually with P–T conditions in the sillimanite stability field. The near isothermal (700–800 °C) condition in the GHS, isobaric condition in the MCTZ together with T–t path evidence of GHS that experienced relatively longer duration of near peak temperatures and rapid cooling towards MCTZ, compares the evolution of GHS and inverted metamorphic gradient closely to channel flow predictions.  相似文献   
4.
Radon and its progeny have been recognized as one of the major contributors to the natural radiation and health hazards in the human dwellings. Even lung cancer is expected if it is present in enhanced levels beyond maximum permissible limit. This paper reports the measurements of indoor radon and its progeny in the urban dwellings of the Etah district of Uttar Pradesh province in Northern India using the cellulose nitrate (LR-115 type-II) plastic track detectors. It is found that the values of radon concentration vary from 3.52 to 248.64 Bq m−3 with a standard deviation of 69.19. The values of radon progeny concentration vary from 0.38 to 26.88 mWL with a standard deviation of 7.48. The effective dose has been calculated and found to vary from 0.05 to 3.76 mSv year−1 with a standard deviation of 1.05. The lifetime fatality risk is found to vary from 0.04 × 10−4 to 2.90 × 10−4. The results have been compared with the results reported in the rural areas of the same district.  相似文献   
5.
Radon, thoron, and their progeny are largest contributors to the radiation dose received by human beings present in the natural environment. The indoor radon depends upon many factors such as building materials, meteorology, ventilation, and occupant’s behavior. This paper presents the measurements of indoor radon, thoron, and their progeny in four villages in rural area of district Kanshiram Nagar (Kasganj) in the state of Uttar Pradesh in Northern India. The concentration of indoor radon and thoron varies from 10.32 to 72.24 and 11.61 to 84.49 Bq m?3 with a geometric mean (GM) of 29.49 and 31.20 Bq m?3, respectively. The concentration of radon and thoron daughters was found to vary from 1.11 to 7.80 and 0.31 to 2.28 mWL, respectively. The annual exposure due to radon and thoron mainly vary from 0.05 to 0.30 WLM. The preliminary results (i.e., bare mode exposure of the LR-115 detectors fixed on cards) of this study have been separately published and compared this recent data with those results.  相似文献   
6.
Distinctive landform of juxtaposition of relatively straight exposures of slope and Quaternary deposits against older rock units in addition to the omission of younger ones are recognized in the Zagros low-folded zone of Mosul area. This phenomenon is attributed to the kinetics and the geometry of basin inversion. Positively inverted faults and their associated folds developed up-growing structures with reverse fault scarps. Those growing structures are passively uplifted above lower blind thrust fault. The up-moving faults were subjected to erosion. The interaction between the rates of erosion and uplift controls the formation of slope and other Quaternary deposits and their distribution. Fast uplift of the reverse faults resulted into formation of cliffs representing the fault scarps and the formation of slope deposits directly next to them. The linear traces of the reverse faults control the straight linear map view distribution of the associated slope deposits. Slower rates of uplift give considerable time to erosion and in consequence the fault scarps are deeply eroded and disappear. This process also resulted into deposition of the other types of Quaternary deposits but still the linear contact between the geological rock units and the Quaternary deposits is existing and easily noticed. The analysis of these features and their interpretation has resulted in a new interpretation of the geological maps of Mosul area and the recognition of many reverse faults that bound the exposed structures. This fault system is used to restore the configuration of the original Late Cretaceous extensional basin.  相似文献   
7.
An integrated approach consisting of fracture analysis, petrography, carbon, oxygen and strontium‐isotope analyses, as well as fluid‐inclusion micro‐thermometry, led to a better understanding of the evolution of fluid–rock interactions and diagenesis of the Upper Permian to Upper Triassic carbonates of the United Arab Emirates. The deposited carbonates were first marked by extensive early dolomitization. During progressive burial, the carbonates were affected by dolomite recrystallization as well as precipitation of vug and fracture‐filling dolomite, quartz and calcite cements. After considerable burial during the Middle Cretaceous, sub‐vertical north–south oriented fractures (F1) were cemented by dolomite derived from mesosaline to hypersaline fluids. Upon the Late Cretaceous maximum burial and ophiolite obduction, sub‐vertical east–west fractures (F2) were cemented by dolomite (Dc2) and saddle dolomite (Ds) derived from hot, highly saline fluids. Then, minor quartz cement has precipitated in fractures from hydrothermal brines. Fluid‐inclusion analyses of the various diagenetic phases imply the involvement of increasingly hot (200°C) saline brines (20 to 23% NaCl eq.). Through one‐dimensional burial history numerical modelling, the maximum temperatures reached by the studied rocks are estimated to be in the range of 160 to 200°C. Tectonically‐driven flux of hot fluids and associated diagenetic products are interpreted to have initiated during the Late Cretaceous maximum burial and lasted until the Oligocene–Miocene compressional tectonics and related uplift. The circulation of such hydrothermal brines led to partial dissolution of dolomites (Dc2 and Ds) and to precipitation of hydrothermal calcite C1 in new (mainly oriented north–south; F3) and pre‐existing, reactivated fractures. The integration of the obtained data confirms that the diagenetic evolution was controlled primarily by the interplay of the burial thermal evolution of the basin and the regional tectonic history. Hence, this contribution highlights the impacts of regional tectonics and basin history on diagenetic processes, which may subsequently affect reservoir properties.  相似文献   
8.
The accurate measurement of precipitation is crucial for hydrological studies. This is especially true for the Hindu Kush–Karakoram–Himalaya (HKKH) mountain region, which is characterized by high spatiotemporal precipitation variability. The paucity of raingauges makes it difficult to measure precipitation in this region precisely. We conducted evaluation of TMPA 3B42V7 and APHRO 1101 in the HKKH area on a daily basis at a spatial resolution of 0.25°?×?0.25°, using 27 raingauges. Statistically, the largest error in the gridded data arose mainly from elevation, followed by volumetric error and Nash–Sutcliffe efficiency. Overall, the TMPA data have a poor correlation with ground observations in the HKKH area, especially for higher altitudes. The western areas are relatively more underestimated and the Karakoram shows higher frequency of bias in the TMPA retrievals. This method could help improve the satellite precipitation estimation algorithm as it considers local physiography and climatic factors.  相似文献   
9.
Radon is a radioactive hazardous and ubiquitous gas. It has been recognized to be one of the major contributors to natural radiation even causing lung cancer if present at enhanced levels. There are large variations in data available in the literature for radium content and radon exhalation rates of various materials. It is a well-documented fact that radon exhalation from the ground surface depends upon a number of parameters such as soil grain size, soil porosity and radium content. For this purpose, in this study the so-called can technique has been used to measure radium content and exhalation rates of radon in soil samples collected from different places of Aligarh, Etah and Mathura districts of Uttar Pradesh??a province in northern India. These districts lie within the subtropical region of the Indo-Gangetic plains. The values of effective radium content are found to vary from 8.11 to 112.83?Bq?kg?1 with a mean value of 33.21?Bq?kg?1 and a standard deviation of 28.15. The values of mass exhalation rates of radon vary from 0.76?×?10?6 to 15.80?×?10?6?Bq?kg?1?day?1 with a mean value of 4.21?×?10?6?Bq?kg?1?day?1, while the surface exhalation rates vary from 1.97?×?10?5 to 41.03?×?10?5?Bq?m?2?day?1 with a mean value of 10.93?×?10?5?Bq?m?2?day?1.  相似文献   
10.
The living Tridacna maxima shell provides an example of a good substrate for many colonizing marine organisms (sclerobionts). Many factors affect the colonization choices of these organisms, such as morphology and size of the host shell, water depth (related to light penetration), suspended particulate load, and turbidity, among others. In addition to these factors, contamination plays an important role in the colonization choice along the coast of the Red Sea in Egypt. In the present study, 25 specimens of T. maxima shells of different sizes were collected at different depths from eight sites along the Egyptian Red Sea coast. There are two types of contamination at these sites. The first type results from anthropogenic activities, such as tourism, fishing, landfilling, shipping, renewal of ship operations, shipyards, dredging, and petroleum production; this type is represented by the El-Esh area, Hurghada Harbor, Safaga Harbor, and Quseir Harbor. The second type results from the natural inputs from wadis and is represented by the El-Esh area, Quseir Harbour, and Wadi El-Gemal, while the Abu Galawa Lagoon, the Abu Ghusun, and the Hamata Reefs represent uncontaminated areas (control areas). The present study documents the colonization phenomena on T. maxima shells at all of the study sites. These phenomena differed from one another in the abundance and diversity of sclerobionts, and unexpectedly, the contaminated areas recorded the highest abundance and diversity of colonizing organisms.  相似文献   
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