The oldest armoured harvestman (Arachnida: Opiliones: Laniatores), from Upper Cretaceous Myanmar amber     

《Cretaceous Research》2016

The oldest laniatorean harvestman, Petrobunoides sharmai gen. et sp. nov. (Opiliones: Laniatores) is described, from the Upper Cretaceous (lowermost Cenomanian) amber of Myanmar. This is the first fossil Laniatores recovered from Southeast Asia, which is placed in the extant family Epedanidae. It is also the first fossil known within the superfamily Epedanoidea; a relatively derived clade of Laniatores restricted to Southeast Asia today. At ca. 99 Ma, this new amber inclusion is substantially older than the previous oldest record of a member of Laniatores from Baltic amber (ca. 44–49 Ma); however, given the Palaeozoic age of Laniatores implied by molecular data, the new record from Burmese amber is probably still too young for constraining or calibrating the date of cladogenesis for total group Laniatores. Nevertheless, it provides a much better constraint for Epedanoidea, adding the first useful laniatorean fossil to provide an internal calibration point for a clade of Grassatores.  相似文献   

Is the interdecadal variation of the summer rainfall over eastern China associated with SST?   总被引：1，自引：0，他引：1  

Dong Si  Zeng-Zhen Hu  Arun Kumar  Bhaskar Jha  Peitao Peng  Wanqiu Wang  Rongqing Han 《Climate Dynamics》2016,46(1-2):135-146

The present study examined the major features of the interdecadal variation of the summer rainfall over eastern China (IVRC) and the possible association with sea surface temperature (SST). We noted that the first leading mode of IVRC (accounting for nearly half of the total variance and with maximum loading for the summer rainfall anomalies over South China) may be not forced by SST. On the other hand, the second and third leading modes [accounting for 17.1 and 13.6 % of the total variance and mainly associated with the summer rainfall anomalies over the Yangtze River valley (YRV) and North China, respectively] in some extent are forced by SST anomalies. These observational results are confirmed by atmospheric general circulation model (AGCM) simulations forced by observed SST. By eliminating the internal dynamical process driven rainfall though ensemble mean, the simulations further suggest an overall enhancement of the intensity of IVRC in the corresponding ensemble mean, especially in the YRV and North China regions, but not in South China. That implies the different role of SST in driving IVRC over different regions.  相似文献   

中国中东部冬季霾日的形成与东亚冬季风和大气湿度的关系   总被引：11，自引：1，他引：10       下载免费PDF全文

吴萍  丁一汇  柳艳菊  李修仓 《Acta Meteorologica Sinica》2016,74(3):352-366

利用1961-2013年中国地面台站长期观测资料和同期NCEP/NCAR再分析资料,以华北、江淮和华南为研究区,分析了中国中东部冬季霾日的形成与东亚冬季风以及大气湿度的关系。结果表明:(1)冬季霾日与东亚冬季风强度成显著的负相关。首先,东亚冬季风强度的减弱使得地面风速减小,进而导致冬季霾日增多。其中,华北7-8 m/s最大风速日数和江淮6-8 m/s最大风速日数的减少,及华南≤2 m/s最大风速日数的增多对各区冬季霾日的增多作用较大。其次,东亚冬季风减弱引起冬季气温的持续升高,易导致冬季霾日的增多,这在华北地区较之在江淮和华南更为明显。(2)由于气候变暖,冬季气温升高,使得近地面相对湿度减小。在江淮和华南地区,冬季霾日的增多与近地面相对湿度的减小显著相关,而在华北地区这种相关较弱。(3)冬季气温升高也有利于大气层结稳定度的增强,3个区域冬季霾日的增多均与大气层结稳定度的增强显著相关,特别是与对流层中低层(850-500 hPa)大气饱和度的降低显著相关。(4)冬季霾日数变化与区域水汽输送关系密切。其中,华北地区的冬季霾日数与水汽总收入成显著正相关,江淮地区与纬向水汽收入成显著正相关,与经向水汽收入成显著负相关,华南地区与经向水汽收入成显著负相关。  相似文献   

MJO prediction skill,predictability, and teleconnection impacts in the Beijing Climate Center Atmospheric General Circulation Model     

《Dynamics of Atmospheres and Oceans》2016

This study evaluates performance of Madden–Julian oscillation (MJO) prediction in the Beijing Climate Center Atmospheric General Circulation Model (BCC_AGCM2.2). By using the real-time multivariate MJO (RMM) indices, it is shown that the MJO prediction skill of BCC_AGCM2.2 extends to about 16–17 days before the bivariate anomaly correlation coefficient drops to 0.5 and the root-mean-square error increases to the level of the climatological prediction. The prediction skill showed a seasonal dependence, with the highest skill occurring in boreal autumn, and a phase dependence with higher skill for predictions initiated from phases 2–4. The results of the MJO predictability analysis showed that the upper bounds of the prediction skill can be extended to 26 days by using a single-member estimate, and to 42 days by using the ensemble-mean estimate, which also exhibited an initial amplitude and phase dependence. The observed relationship between the MJO and the North Atlantic Oscillation was accurately reproduced by BCC_AGCM2.2 for most initial phases of the MJO, accompanied with the Rossby wave trains in the Northern Hemisphere extratropics driven by MJO convection forcing. Overall, BCC_AGCM2.2 displayed a significant ability to predict the MJO and its teleconnections without interacting with the ocean, which provided a useful tool for fully extracting the predictability source of subseasonal prediction.  相似文献   

卫星臭氧资料的发展与应用     

刘寅  邹晓蕾 《气象学报》2016,74(1):1-17

随着卫星探测技术的进步、天气学和气候学理论的不断完善,以及高性能计算机广泛应用,卫星臭氧资料的种类得到极大丰富并被应用到多个研究领域中,取得了一系列重要成果。文中介绍了主要星载臭氧探测仪的发展概况,回顾了卫星臭氧资料在气象领域的应用研究成果,主要包括卫星臭氧资料在气旋或低压过程中、全球或区域臭氧的气候分布及变化特征、高原臭氧分布及变化特点、数值应用等方面的应用研究,并展望了卫星臭氧资料研究的未来发展趋势。   相似文献   

中国植物物候变化特征及其对降水变化的响应          下载免费PDF全文

赖欣  范广洲 《高原山地气象研究》2016,36(3):44-52

利用1963~1988年中国木本草本植物物候观测资料,运用趋势分析和相关分析方法,研究了26年中国20个物候站点植物始展叶期、始花期、始落叶(黄枯)期物候变化特征及其对降水变化的响应。结果表明:1963~1988年我国植物始展叶期、始花期、始落叶(黄枯)期均以推迟趋势为主;春季始展叶期、始花期,东北、华北以提前趋势为主,其他各区以推迟趋势为主;秋季始落叶(黄枯)期华北以提前趋势为主,其他各区以推迟趋势为主;1980年前后的物候期变化与1963~1988年的变化相同;春季物候期平均值差异多在-3~6天,秋季物候期平均值差异多在-10~10天;我国植物的始展叶期、始花期、始落叶(黄枯)期对于之前月份的累积降水量有不同程度的响应,物候期对该物候期前1月至前3月的累积降水量响应最为明显;我国春季物候期与降水量以正相关为主,秋季物候期与降水量则以负相关为主。   相似文献   

气候变化情景下黄淮海区域热量资源及夏玉米温度适宜度   总被引：2，自引：0，他引：2       下载免费PDF全文

李萌  申双和  吕厚荃  韩艳  褚荣浩  沙修竹 《大气科学学报》2016,39(3):391-399

利用黄淮海区域90个站点1971—2000年逐日气象资料以及国家气候中心发布的未来气候变化情景(A1B)下区域气候模式(Reg CM3)模拟的黄淮海区域1951—2070年0.25°×0.25°格点气象资料,结合夏玉米主要生育期对温度的需求,构建了黄淮海区域的温度适宜度和变异系数模型,并对1951—2070年黄淮海区域热量资源、夏玉米主要生育期的温度适宜度及其变异系数的时空变化特征进行分析。结果表明:1)黄淮海区域≥10℃积温和80%保证率下日平均温度≥10℃的初日均呈现由北向南依次增加的趋势,且随时间推移,分别呈增加和提前趋势。2)黄淮海区域夏玉米播种—出苗期的温度适宜度随时间整体呈逐渐上升的变化趋势、其变异系数随时间呈降—升—降的变化趋势;出苗—抽雄期的温度适宜度随时间呈先降后升的变化趋势、其变异系数呈降—升—降—升的变化趋势;抽雄—成熟期的温度适宜度空间上呈现2010年前北低南高、未来情景下中部低四周高的分布趋势,时间上呈2010年前稳定、未来情景下先降后升的变化趋势,其变异系数呈相反变化趋势;3)黄淮海区域夏玉米温度适宜度及其变异系数从播种—出苗期—出苗—抽雄期—抽雄—成熟期均呈反相位的变化关系。  相似文献   

Influence of coastal wind on surface ozone and nitrogen oxides in suburban Shanghai     

Wenpo Shan  Peng Yang  Haixia Lu  Kefeng Ma  Zhixin Huang 《Asia-Pacific Journal of Atmospheric Sciences》2016,52(5):451-458

Surface ozone, NO, NO₂, and NO _x were measured at a coastal site (Shihua) and a nearby inland site (Zhujing) in suburban Shanghai for the whole year of 2009. More days with ozone pollution in a longer time range were observed at the coastal site than the inland site. The diurnal variations of NO _x concentrations were obviously higher at Zhujing station, while those of ozone concentrations were higher at Shihua station, indicating their different air pollution conditions. Coastal wind has significant influence on the levels and characteristics of the air pollutants. The ozone concentrations during maritime winds (MW) were much higher than those during continental winds (CW) at each of the site, while the NO and NO₂ concentrations were both opposite. The ozone concentrations at Shihua station were much higher than those at Zhujing station, while the NO and NO₂ concentrations were both opposite. The ozone concentrations at both of the two sites showed a distinct “weekend effects” and “weekdays effects” patterns during CW and MW, respectively. Correlation analysis of the pollutants showed that, the compounds during MW were more age than those during CW, and the compounds at Shihua were more age than those at Zhujing. The air pollutions at both of the two sites are mainly associated with the pollutants emitted in this region instead of long range transport.  相似文献   

1991年5-7月江淮洪涝:水汽和冷空气的作用比较     

姜颖  陆尔 《气象科学》2016,36(3):382-388

对1991年5-7月江淮流域持续性暴雨的环流异常进行分析,比较造成此次洪涝的水汽输送和冷空气活动重要性。结果表明：（1）东亚大槽维持在中国东北上空发展明显,同时鄂霍次克海上空没有建立强大阻高,这种形势有利于冷空气持续向南侵袭,盛行经向环流。此外,低纬度地区,西太平洋副热带高压主体位置于常年同期相比,明显偏西、偏强,有利于暖湿气流沿副热带高压北上到达江淮流域,与北方冷空气辐合形成强降水。（2）通过定义I_T和I_q分别表征温度与水汽对降水的贡献,发现此次江淮流域地区强降水是由对流层低层水汽异常增多和气温异常偏低共同造成的,作用基本相当。  相似文献   

Estimating winter wheat biomass by assimilating leaf area index derived from fusion of Landsat-8 and MODIS data     

《International Journal of Applied Earth Observation and Geoinformation》2016

A sufficient number of satellite acquisitions in a growing season are essential for deriving agronomic indicators, such as green leaf area index (GLAI), to be assimilated into crop models for crop productivity estimation. However, for most high resolution orbital optical satellites, it is often difficult to obtain images frequently due to their long revisit cycles and unfavorable weather conditions. Data fusion algorithms, such as the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) and the Enhanced STARFM (ESTARFM), have been developed to generate synthetic data with high spatial and temporal resolution to address this issue. In this study, we evaluated the approach of assimilating GLAI into the Simple Algorithm for Yield Estimation model (SAFY) for winter wheat biomass estimation. GLAI was estimated using the two-band Enhanced Vegetation Index (EVI2) derived from data acquired by the Operational Land Imager (OLI) onboard the Landsat-8 and a fusion dataset generated by blending the Moderate-Resolution Imaging Spectroradiometer (MODIS) data and the OLI data using the STARFM and ESTARFM models. The fusion dataset had the temporal resolution of the MODIS data and the spatial resolution of the OLI data. Key parameters of the SAFY model were optimised through assimilation of the estimated GLAI into the crop model using the Shuffled Complex Evolution-University of Arizona (SCE-UA) algorithm. A good agreement was achieved between the estimated and field measured biomass by assimilating the GLAI derived from the OLI data (GLAI_L) alone (R² = 0.77 and RMSE = 231 g m⁻²). Assimilation of GLAI derived from the fusion dataset (GLAI_F) resulted in a R² of 0.71 and RMSE of 193 g m⁻² while assimilating the combination of GLAI_L and GLAI_F led to further improvements (R² = 0.76 and RMSE = 176 g m⁻²). Our results demonstrated the potential of using the fusion algorithms to improve crop growth monitoring and crop productivity estimation when the number of high resolution remote sensing data acquisitions is limited.  相似文献