渤海海效应暴雪云特征的观测分析   总被引：1，自引：0，他引：1       下载免费PDF全文

郑怡  高山红  吴增茂 《应用气象学报》2014,25(1):71-82

利用静止卫星 (GMS-5, GOES-9, MTSAT) 红外数据与CloudSat卫星云剖面雷达数据、NCEP FNL分析资料与常规观测资料,对2001—2010年发生的12次渤海海效应暴雪过程中云的演变特征、渤海热力作用与暴雪云团垂直结构及相态组成进行了观测分析。发现不同生成源地的暴雪云通常在渤海上快速发展,云中多存在水平范围可达100~300 km的密实条状或块状云团,其下对应主要降雪区域;暴雪云生成源地可分为渤海湾及莱州湾附近、渤海中部、辽东湾附近3种,暴雪云在海上移动主要受850 hPa风场影响;渤海暖海面与其上冷空气间的热量、水汽交换形成的不稳定层结条件,导致暴雪云进一步发展;暴雪云发展旺盛时期高度可达4 km,其冰水含量最大值达600 mg·m-3且主要集中在2 km高度附近,平均值可达303 mg·m-3,冰粒子有效半径最大值约为120 μm,平均值约为91 μm。  相似文献   

OH in the tropical upper troposphere and its relationships to solar radiation and reactive nitrogen     

R. S. Gao  K. H. Rosenlof  D. W. Fahey  P. O. Wennberg  E. J. Hintsa  T. F. Hanisco 《Journal of Atmospheric Chemistry》2014,71(1):55-64

In situ measurements of [OH], [HO₂] (square brackets denote species concentrations), and other chemical species were made in the tropical upper troposphere (TUT). [OH] showed a robust correlation with solar zenith angle. Beyond this dependence, however, [OH] did not correlate to its primary source, the product of [O₃] and [H₂O] ([O₃]?[H₂O]), or its sink [NO_y]. This suggests that [OH] is heavily buffered in the TUT. One important exception to this result is found in regions with very low [O₃], [NO], and [NO_y]. Under these conditions, [OH] is highly suppressed, pointing to the critical role of NO in sustaining OH in the TUT and the possibility of low [OH] over the western Pacific warm pool due to strong marine convections bringing NO-poor air to the TUT. In contrast to [OH], [HO_x] ([OH] + [HO₂]) correlated reasonably well with [O₃]?[H₂O]/[NO_y], suggesting that [O₃]?[H₂O] and [NO_y] are the significant source and sink, respectively, of [HO_x].  相似文献   

Investigation of Uncertainties of Establishment Schemes in Dynamic Global Vegetation Models简     

SONG Xiang  ZENG Xiaodong 《大气科学进展》2014,31(1):85-94

In Dynamic Global Vegetation Models （DGVMs）, the establishment of woody vegetation refers to flowering, fertiliza- tion, seed production, germination, and the growth of tree seedlings. It determines not only the population densities but also other important ecosystem structural variables. In current DGVMs, establishments of woody plant functional types （PFTs） are assumed to be either the same in the same grid cell, or largely stochastic. We investigated the uncertainties in the competition of establishment among coexisting woody PFTs from three aspects： the dependence of PFT establishments on vegetation states; background establishment; and relative establishment potentials of different PFTs. Sensitivity experi- ments showed that the dependence of establishment rate on the fractional coverage of a PFT favored the dominant PFT by increasing its share in establishment. While a small background establishment rate had little impact on equilibrium states of the ecosystem, it did change the timescale required for the establishment of alien species in pre-existing forest due to their disadvantage in seed competition during the early stage of invasion. Meanwhile, establishment purely fiom background （the scheme commonly used in current DGVMs） led to inconsistent behavior in response to the change in PFT specification （e.g., number of PFTs and their specification）. Furthermore, the results also indicated that trade-off between irtdividual growth and reproduction/colonization has significant influences on the competition of establishment. Hence, further development of es- tablishment parameterization in DGVMs is essential in reducing the uncertainties in simulations of both ecosystem structures and successions.  相似文献   

Distinct quasi-biweekly features of the subtropical East Asian monsoon during early and late summers   总被引：2，自引：0，他引：2  

Jing Yang  Qing Bao  Bin Wang  Dao-Yi Gong  Haozhe He  Miao-Ni Gao 《Climate Dynamics》2014,42(5-6):1469-1486

Using Global Precipitation Climatology Project daily rainfall and ERA interim reanalysis data, we investigate the distinct characteristic of quasi-biweekly variation (QBV: 12–20 days) over East Asia (EA) during early (June 10–July 20) and late (July 21–August 31) summer. The QBV maximum variance is found over the core region of EA (30°–40°N, 110°–130°E), which includes eastern China (lower reaches of the Yellow, Huaihe, and Yangtze rivers) and the Korean Peninsula. At both its peak wet and dry phases, QBV over the core region has a baroclinic structure, but with different spatial distributions, different lower-level prevalent wind anomalies, and different upper-level major circulation anomalies in the two subseasons. Meanwhile, the two subseasons have different propagating tracks prior to reaching the peak phase, and different precursors associated with the local genesis of QBV. Furthermore, during the transition from the peak dry to peak wet phase of QBV, the major monsoon circulations have different behaviors that tropical monsoon trough extends eastward in early summer but retreats westward in late summer and the South Asia high (SAH) and western North Pacific (WNP) subtropical high move toward (away from) each other in early (late) summer. The abrupt change of mean state in mid to late July, which includes the northward migration of westerly jet, SAH and WNP, and the weakening and broken of westerly jet, is considered the root cause of the change in behavior of QBV. Finally, we indicate that the tropical monsoon trough and midlatitude westerly jet are possible sources of QBV over subtropical EA in both subseasons and provide useful guidance for 2–3 week predictions over EA.  相似文献   

地基SAR在滑坡形变监测中的应用     

周志伟  程翔  周伟  郝卫峰  肖海斌  陈鸿杰  杨魁 《测绘通报》2022,(7):60-63

地基InSAR是近年发展起来的基于地基SAR (GB-SAR)获取地表形变的一种新的技术手段,分辨率高、可实时监测,实现毫米级形变监测精度,为近距离滑坡实时监测与预警提供了先进的技术手段。本文首先以澜沧江某滑坡体为研究对象,在滑坡体对岸设立固定站点,按固定频率进行GB-SAR数据采集;然后通过先后两景影像形成干涉对,利用相干阈值方法提取相干点目标;最后利用形变模型提取滑坡体形变结果。研究表明,地基SAR可获得整个滑体形变边界、形变大小空间分布及时间变化历程,对滑坡体灾害实时监测非常有效,可为滑坡灾害监测及预警提供参考。  相似文献   

Exploring the dynamics of the disaggregated intercity corporate network in the Yangtze River Delta,China: a relational event approach     

Li  Luqi  Derudder  Ben  Shen  Wei  Kong  Xiang 《Journal of Geographical Systems》2022,24(1):115-140

Journal of Geographical Systems - There has been a proliferation of studies trying to explain the driving forces behind the formation and evolution of intercity corporate networks. Previous...  相似文献   

滑坡灾害监测的圆弧合成孔径雷达大气相位校正方法     

杜年春  王玉明  沈向前  谢翔 《测绘学报》2022,51(10):2139-2148

地基圆弧合成孔径雷达通过形变值测量实现滑坡预警,是一种重要的滑坡灾害监测遥感手段。大气相位校正影响形变值测量精度,是长时间稳定监测的关键技术。本文提出一种基于网格划分的两阶段大气相位校正方法。该方法通过特征提取及分类获得永久散射点,基于此实现监测点的自动筛选;利用网格估计大气相位,有效降低运算量,提高了计算效率;结合空间滤波和时间序列滤波,保证了大气相位估计的准确性。实测数据处理结果表明了该文所提方法在大气相位校正方面的有效性。  相似文献   

基于回归分析法的地下水位预测研究     

高尚鹏  赵庆鲁  邵志恒 《地下水》2014,(3):53-55

彭楼灌区位于山东省聊城市西南部,为引黄灌溉灌区。2002年彭楼灌区复灌以来,有效缓解当地水资源紧缺的矛盾。为研究彭楼灌区引黄水量对地下水位的影响,采用回归分析法,具体分析地下水位变差与引黄水量、干旱指数的回归关系,建立回归方程。通过实例分析检验,建立的回归方程可作为进行彭楼灌区地下水位预测的一种方法。  相似文献   

昂青矿区多金属矿床成因及找矿远景     

颜翠翠  毛晓东  张俊海  刘成  高龙 《四川地质学报》2014,(4):510-513

昂青矿区位于昌都—芒康成矿带的玉龙—多霞松多铜钼金银多金属找矿靶区,是川西藏东三江地区最具经济价值的矿集区之一。通过多种分析研究手段,对矿区进行详查,研究矿床成矿作用,探讨矿床成因,对查明矿区主矿体空间展布形态及特征有重要意义。  相似文献   

我国硫资源供需状况及需求预测     

赵明  陈春琳  高鹏  孙小红 《化工矿产地质》2014,36(3):173-181

全球硫资源特征及国内硫资源供需现状表明,国内硫资源贫乏,硫资源生产与消费逐年增加,尤其磷肥生产对硫资源的需求越来越迫切,预计到2020~2025年磷肥用硫量将达到峰值1620万t左右,不包括出口磷肥耗硫量。因此,加强硫资源的综合利用、加大硫铁矿找矿及矿山设计是非常有必要的。  相似文献