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在NCEPGDAS中同化MSG和GOES资料 总被引：1，自引：0，他引：1
首次将MSG-2（Meteosat Second Generation-2）卫星上的旋转增强可见光及红外成像仪（Spin—ning Enhanced Visibleand Infrared Imager,SEVIRI）的观测资料同化到美国国家环境预报中心（Na—tional Centers for Environmental Prediction,NCEP）全球资料同化系统（globaldataassimilationsys—tern,GDAS）中。对当前的地球静止业务环境卫星（Geostationary Operational Environmental Satel—lite,GOES）成像仪资料的同化问题也进行了进一步探讨。利用CRTM（The Community Radiative Transfer Model）模式,对SEVIRI辐射率观测资料进行了模拟。为了对红外辐射率资料进行模拟,CRTM模式中的几个关键部分得到改进,例如：动态更新地面发射率资料以及采用了快速精确的气体吸收模块。为了改进对SEVIRI和GOES成像仪辐射率资料的模拟效果,采用了GSICS（The Global Space—Based Inter—Calibration System）标定订正。初步研究结果表明,包含对SEVIRI辐射率资料的水汽通道（6．25和7．35μm）和二氧化碳通道（13．40μm）的同化对GFS（Global Forecast System）6d预报具有显著的正影响;而对其他5个SEVIRI红外窗口通道资料的同化则减小了这种正影响。通过应用GSICS标定算法,订正了SEVIRI和GOES-12成像仪观测资料的偏差,提高了对GFS预报的影响。此外,还需作进一步研究来提高对SEVIRI红外窗口通道辐射率资料同化的有效性。 相似文献
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Yingxia Lu Baosheng Li Xiaohao Wen Shifan Qiu Fengnian Wang Dongfeng Niu Zhiwen Li 《中国地理科学(英文版)》2010,20(3):243-251
The upmost segment(Holocene series)of the Milanggouwan stratigraphic section(MGS1)in the Salawusu River valley shows 11 sedimentary cycles of dune sands and fluvio-lacustrine facies,or dune sands and paleosols.The analysis of the magnetic susceptibility of this segment suggests that there are 11 magnetic susceptibility cycles with the value alternating from low to high,in which the layers of the dune sands correspond to the lower value of the magnetic susceptibility and the layers of fluvio-lacustrine facies and paleosols correspond to the higher peaks.The study reveals that the low and high magnetic susceptibility values indicate the climate dominated by cold-arid winter monsoon and warm-humid summer monsoon of East Asia,respectively,and the study area has experienced at least 22 times of mil-lennial-centennial scales climate alternation from the cold-arid to the warm-humid during the Holocene.In terms of the time and the climate nature,the variations basically correspond to those of the North Atlantic and some records of cold-warm changes in China as well.They might be caused by the alternation of winter and summer monsoons in the Mu Us Desert induced by global climate fluctuations in the Holocene. 相似文献
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Shuhuan Du Baosheng Li Dongfeng Niu David Dian Zhang Xiaohao Wen Deniu Chen Yi Yang Fengnian Wang 《Chemie der Erde / Geochemistry》2011,(1):87-95
The MGS5 segment of the Milanggouwan stratigraphical section in China's Salawusu River Valley records 8.5 sedimentary cycles consisting of dune sands alternating with fluviolacustrine facies or/and paleosols. Based on a comprehensive analysis of the distribution of Rb and Sr within the segment and paleoecological evidence (fossils), it appears that the observed sedimentation cycles mainly resulted from fluctuations between dry-cold and warm-humid climates, which indicates that the MGS5 segment experienced at least eight cold-dry and nine warm-humid climatic fluctuations. Of these, 12 cold–warm climate fluctuations correspond to DO20–DO25 and stadia 21–26 recorded by the NGRIP ice cores. Another five cold–warm climatic fluctuations that occurred during MGS5e correspond to five substages (5e1–5e5) recorded by the GRIP ice cores from Greenland. This kind of high-frequency climatic fluctuation on a kiloyear scale was mainly subject to variations in the strength of the East Asian winter and summer monsoons. 相似文献
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Water-ice and dust optical depths in Mars’ north polar region are mapped as function of season, latitude and longitude, and their characteristics and variability on a geographic, seasonal, and interannual basis are discussed. We use water-ice and dust optical depth data provided by the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES), covering nearly three northern spring and summer periods. We find that interannual variability exists in both the water ice and dust behavior, although there are trends that repeat year to year as well. The optical thickness of the north polar hood (NPH) exhibits interannually varying longitudinal structure, both during springtime recession and late-summer onset. We define the characteristics associated with the transition to and from the NPH and find that the disappearance occurs near Ls=75° and the reappearance near Ls=160-165°. We find that the late spring to early summer time frame is characterized by very low water-ice optical depths and enhanced dust activity, with a preference for lower water-ice and higher dust optical depths in the 0-90°W quadrant. We see possible evidence for stationary wavenumber 2 systems in a few of the maps examined. 相似文献
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萨拉乌苏河流域MGS2层段粒度与CaCO3记录的千年尺度气候变化 总被引：2，自引：0，他引：2
测定、分析毛乌素沙漠东南缘萨拉乌苏河流域米浪沟湾剖面MGS2层段的粒度与CaCO3,发现该层段不同沉积相粒度Mz和σ呈现峰谷变化,CaCO3含量在沙丘砂及其上覆的河流相和湖沼相中依次变化于0-2.94%(平均值0.39%)、0.14%-2.68%(1.43%)和0.39%-15.57%(8.82%),并与Mz呈显著相关,构成与沉积旋回波动韵律相同的5.5个峰谷交替的粒度与CaCO3旋回。研究表明,毛乌素沙漠冬季风盛行时期沙丘砂强烈堆积,CaCO3发生迁移;夏季风盛行时期河流相和湖沼相发育,粉砂和粘土含量增加,CaCO3相对聚集。这些旋回代表东亚冬夏季风千年尺度交替变化的气候旋回。 相似文献
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毛乌素沙漠东南缘萨拉乌苏河流域米浪沟湾剖面MGS1层段含有11个由古沙丘砂与河湖相或古土壤构成的沉积旋回。通过对该层段粒度和CaCO3的分析,发现其河湖沼相和古土壤的平均粒径、分选系数、偏度和峰态的值明显高于古沙丘砂;CaCO3含量在古沙丘砂及其上覆的河湖相和古土壤中依次变化于0.07%~0.32%（平均值为0.16%）、0.05%~1.50%（0.27%）和0.06%~1.42%（0.64%）,并与平均粒径呈显著相关（相关系数0.8）;构成与沉积旋回波动韵律相同的11个峰谷交替的粒度和CaCO3旋回,指示了全新世气候冷、暖的变化过程和东亚冬夏季风千年尺度交替变化的气候旋回。这些旋回中的冬季风主导时期可与北大西洋8 200、5 000、4 000、2 700、1 400 a BP等寒冷事件进行对比,和中国若干地点的气候波动具有良好对应关系,可能表明全新世东亚季风在全球大气、海洋、陆地和全球冰量变化的共同作用下,表现为干冷冬季风和暖湿夏季风的相互交替的千年尺度的气候变化特征。 相似文献
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Li BaoSheng Chen DeNiu David Dian Zhang Wen XiaoHao Qiu ShiFan Ou XianJiao Du ShuHuan Niu DongFeng Yang Yi Ye JianPing Guo YunHai 《中国科学D辑(英文版)》2008,51(3):339-348
Contemporaneous with MIS3, the MGS3 segment of the Milanggouwan stratigraphic section in the Salawusu River Valley, Mu Us Desert, China contains fossil gastropods (terrestrial and freshwater snails) in strata 33LS, 35LS, 37FL and 39LS. Examination of these fossils revealed 11 species belonging to 8 families and 10 genera. They can be classified as: (1) assemblage of Gyraulus and Galba mainly consisting of Gyraulus convexiusculus, Gyraulus sibiricus, Galba pervia and Galba superegra Gredler, etc. (2) assemblage of Vallonia mainly consisting of terrestrial snails, such as Vallonia patens, Pupilla muscorum and Discus paupe, etc. Based on the dating results, and the living habits, living conditions, and geographic distribution of their extant species, we suggest that: the ages of 33LS, 35LS, 37FL, and 39LS are 26000, 29000, 33000 and 38000 a, respectively, corresponding well to the interstadial period in GRIP 4, 5, 6 and 10 in terms of chronology and climatic characters; 33LS, 35LS and 39LS represent very warm-humid periods, while 37FL represents a less warm-humid period; the four periods of climatic fluctuations recorded in MGS3 were related to the strong impact of the summer monsoon in East Asia in Mu Us Desert of China during the interstadial of MIS3 on a global climatic background. 相似文献
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萨拉乌苏河流域MGS2层段主要氧化物变化及其指示的气候波动 总被引：4，自引：2，他引：2
萨拉乌苏河流域与MIS2相同时代的MGS2地层段记录了5.5个由风成砂与河流相或湖沼相构成的沉积旋回,通过对各沉积旋回的主要氧化物分析表明：河湖相中Al2O3、TOFE、K2O、MgO、CaO、Na2O、TiO含量通常明显高于风成砂,而SiO2含量则呈现相反的变化,构成了与沉积旋回相对应的5.5个主要氧化物变化旋回。结合各主要氧化物的化学迁移特性和剖面所在区域的地貌特征进行分析,认为该剖面的主要氧化物变化旋回是气候波动的反映,一个主要氧化物含量变动旋回指示了一个干冷-暖湿旋回,也即一个冬夏季风先后演替的气候旋回。MGS2持续的时间仅为12 ka,一个冬夏季风环境的变化大致平均仅需要2 ka,一个冬季风或者夏季风环境的平均持续时间大约1 ka。显然,这是一个千年尺度的环境变化。研究还表明,MGS2气候波动与晚冰期气候变化以及相关的Heinrich事件具有良好的对应关系。可以推断,MGS2记录的千年尺度环境变化是全球环境变化在本区域的反映。 相似文献