阜新地区1951—2010年降水变化特征

根据阜新地区2个观测站1951-2010年逐月和逐年降水资料,通过趋势分析、Mexicohat小波变换和Mann-Kendall突变检验等方法,分析了阜新地区降水的气候变化特征。结果表明：阜新地区近60 a来年降水量呈下降趋势,下降速率为10.7 mm/10a;降水量年际变化明显,极易出现旱涝灾害。除春季降水略有增加外,其他三季均呈减少趋势。年降水量和季节降水量均有准12 a和18 a的周期振荡。除春季降水量没有明显突变点外,夏、秋、冬三季均存在突变点,其中夏季降水量存在3个突变年份,分别为1967年、1978年和1986年,秋季降水量在1996年存在突变,冬季降水量在2004年存在突变。     

Sensitivity of Tropical Cyclone Precipitation to Atmospheric Moisture Content： Case Study of Bilis （2006）

In this article, the authors used the Weather Research and Forecast model to investigate the sensitivity of tropical cyclone Bilis' total precipitation to ambient water vapor content. The tropical cycl...     

宁波市轨道交通管线详查方法

根据宁波市轨道交通建设过程中对管线详查的要求,介绍相应管线探测的主要技术方法,并成功解决深埋金属管线和深埋非封闭非金属管线的探测技术方法,同时优化了数据处理技术,提高数据查询效率。     

福田站基坑监控量测信息管理系统的建立与应用

根据广深港客专福田站超深超宽基坑施工监控量测的需要,应用远程数据通讯技术、数据库技术和GIS技术设计并建立了工程监控量测信息管理管理系统,统计和分析功能提高了监控量测信息的反馈效率,解决了监控量测与施工配合的问题,工程实践表明系统提高了监控量测信息的反馈效率,达到了福田站基坑监控量测信息化管理的需求。     

The Mesoscale Predictability of a Heavy Precipitation Event

Using the mesoscale model MM5, the development of initial condition uncertainties at different scales and amplitudes and their influences on the mesoscale predictability of the ＂0185＂ Shanghai heavy precipitation event are investigated. It is found that different initial conditions obtained from different globe model analyses lead to large variations in the simulated location and strength of the heavy precipitation, and the scales and amplitudes of the initial condition perturbations significantly influence the model error growth. The power spectrum evolution of the difference total energy （DTE） between a control simulation and a sensitivity experiment indicates that the error growth saturates after 12 h, which is the predictable time limit of the heavy precipitation event. The power spectrum evolution of the accumulated precipitation difference between the control and sensitivity simulations suggests a loss of the mesoscale predictability for precipitation systems of scales smaller than 300 kin, i.e., the predictable space for the heavy precipitation event is beyond 300 km. The results also show that the initial uncertainties at larger scales and amplitudes generally result in larger forecast divergence than the uncertainties at smaller scales and amplitudes. The predictable forecasting time and space can be expanded （e.g., from 12 to 15 h, and from beyond 300 kin to beyond 200 km） under properly prescribed initial perturbations at smaller scales and amplitudes.     

Seasonal Prediction of the Global Precipitation Annual Modes with the Grid-Point Atmospheric Model of IAP LASG

A right annual cycle is of critical importance for a model to improve its seasonal prediction skill. This work assesses the performance of the Grid-point Atmospheric Model of IAP LASG （GAMIL） in retrospective prediction of the global precipitation annual modes for the 1980 2004 period. The annual modes are gauged by a three-parameter metrics： the long-term annual mean and two major modes of annual cycle （AC）, namely, a solstitial mode and an equinoctial asymmetric mode. The results demonstrate that the GAMIL one-month lead prediction is basically able to capture the major patterns of the long-term annual mean as well as the first AC mode （the solstitial monsoon mode）. The GAMIL has deficiencies in reproducing the second AC mode （the equinoctial asymmetric mode）. The magnitude of the GAMIL prediction tends to be greater than the observed precipitation, especially in the sea areas including the Arabian Sea, the Bay of Bengal （BOB）, and the western North Pacific （WNP）. These biases may be due to underestimation of the convective activity predicted in the tropics, especially over the western Pacific warm pool （WPWP） and its neighboring areas. It is suggested that a more accurate parameterization of convection in the tropics, especially in the Maritime Continent, the WPWP and its neighboring areas, may be critical for reproducing the more realistic annual modes, since the enhancement of convective activity over the WPWP and its vicinity can induce suppressed convection over the WNP, the BOB, and the South Indian Ocean where the GAMIL produces falsely vigorous convections. More efforts are needed to improve the simulation not only in monsoon seasons but also in transitional seasons when the second AC mode takes place. Selection of the one-tier or coupled atmosphere-ocean system may also reduce the systematic error of the GAMIL prediction. These results offer some references for improvement of the GAMIL seasonal prediction skill.     

A Case Study on the Triggering of Thermal Convective Precipitation

Thermal convective precipitation （TCP） often occurs over mainland China in summer when the area is dominated by the western Pacific subtropical high （WPSH）. It is well known that the WPSH often brings about large scale subsidence, then why could deep moist convection occur and where does the water vapor come from？ In this paper, a deep convective precipitation case that happened on 2 August 2003 is studied in order to address these two questions. First, the characteristics of the TCP event are analyzed using the Tropical Rainfall Measuring Mission （TRMM） satellite data, automatic weather station observations, and the data from the US National Centers for Environmental Prediction （NCEP）. Second, water vapor sources are identified through examining surface evaporation, water vapor advection, and water vapor flux divergence calculated by using a regionally averaged water vapor budget equation. Furthermore, using an Advanced Regional Eta-coordinate Model （AREM）, contributions of sensible and latent heat fluxes to the TCP are compared through four sensitivity experiments. The results show that in the regions controlled by the WPSH, surface temperature rises rapidly after sunrise. Upon receiving enough sensible heat, the air goes up and leads to convergence in the lower atmosphere. Then the water vapor assembled from the surroundings and the ground surface is transported to the upper levels, and a favorable environment for the TCP forms. A model data diagnosis indicates that about half of precipitable water comes from the convergence of horizontal fluxes of water vapor, and the other half from surface evaporation, while little is from advection. Additional sensitivity experiments prove that both sensible and latent heating are essential for the onset of the TCP. The sensible heat flux triggers thermodynamic ascending motion, and the latent heat flux provides water vapor, but the contribution to TCP from the latter is a little smaller than that from the former.     

The Impact of Mid- and High-Latitude Rossby Wave Activities on the Medium-Range Evolution of the EAP Pattern During the Pre-Rainy Period of South China

Based on the NCEP DOE AMIP II daily reanalysis data (1979{2005), the evolution of the East Asia/Pacific(EAP) teleconnection pattern during the pre-rainy period of South China is studied on the medium-range time scale. It is found that positive and negative EAP patterns share a similar generation process. In the middle and upper troposphere, Rossby wave packets emanating from the northeast Atlantic or Europe propagate toward East Asia along the Eurasian continent waveguide and finally give rise to the three anomaly centers of the EAP pattern over East Asia. Among the three anomaly centers, the western Pacific subtropical center appears the latest. Rossby wave packets propagate from the high latitude anomaly center toward the mid-latitude and the subtropical ones. The enhancement and maintenance of the subtropical anomaly center is closely associated with the subtropical jet waveguide and the incoming Rossby wave packets from the upstream. In the lower troposphere, Rossby wave packets emanate from the subtropical Asia toward East Asia. Positive and negative EAP patterns could not be regarded as "mirrors" to each other with simply re- versed phase. For the positive pattern, the positive height anomaly center around the Scandinavia Peninsula keeps its strength and position during the mature period, and the Rossby wave packets thus propagate persistently toward East Asia, facilitating a longer mature time of the positive pattern. As for the formation of the negative EAP pattern, however, the incoming Rossby wave energy from the upstream contributes to both the enhancement and southeastward movement of the negative anomaly belt from the Yenisei River to the Bering Strait and the positive anomaly center around Mongolia. At the peak time, the two anomlous circulations are evolved into the Northeast Asia and the mid-latitude anomaly centers of the negative pattern, respectively. The energy dispersion of Rossby wave packets is relatively fast due to the predominant zonal circulation in the extratropics, causing a shorter mature period of the negative pattern. During the pre-rainy period of South China, the prevalence of the EAP pattern signiˉcantly affects the rainfall over the region south of the Yangtze River. The positive (negative) EAP pattern tends to causepositive (negative) precipitation anomalies in that region. This is di?erent from the earlier research findingsbased on monthly mean data.     

Intraseasonal variability in the equatorial Atlantic-West Africa during March–June

Intraseasonal (30–80 days) variability in the equatorial Atlantic-West African sector during March–June is investigated using various recently-archived satellite measurements and the NCEP/DOE AMIP-II reanalysis daily data. The global connections of regional intraseasonal signals are first examined for the period of 1979–2006 through lag-regression analyses of convection (OLR) and other dynamic components against a regional intraseasonal convective (OLR) index. The eastward-propagating features of convection can readily be seen, accompanied by coherent circulation anomalies, similar to those for the global tropical intraseasonal mode, i.e., the Madden–Julian oscillation (MJO). The regressed TRMM rainfall (3B42) anomalies during the TRMM period (1998–2006) manifest similar propagating features as for the regressed OLR anomalies during 1979–2006. These coherent features hence tend to suggest that the regional intraseasonal convective signals might be mostly a regional response to, or closely associated with the MJO, and probably contribute to the MJO’s global propagation. Atmospheric and surface intraseasonal variability during March–June of 1998–2006 are further examined using the high-quality TRMM Microwave Imager (TMI) sea surface temperature (SST), columnar water vapor, and cloud liquid water, and the QuikSCAT oceanic winds (2000–2006). Enhanced (suppressed) convection or positive (negative) rainfall anomalies approximately cover the entire basin (0°–10°N, 30°W–10°E) during the passage of intraseasonal convective signals, accompanied by anomalous surface westerly (easterly) flow. Furthermore, a unique propagating feature seems to exist within the tropical Atlantic basin. Rainfall anomalies always appear first in the northwestern basin right off the coast of South America, and gradually extend eastward to cover the entire basin. A dipolar structure of rainfall anomalies with cross-equatorial surface wind anomalies can thus be observed during this evolution, similar to the anomaly patterns on the interannual time scale discovered in past studies. Coherent intraseasonal variations and patterns can also be found in other physical components.

基于BP神经网络的地质灾害细网格预报模型

地质灾害成因复杂,其中以气象因素、地质地貌因素引发的地质灾害最为常见.以金华地区为例,通过对金华市地质地貌条件及其对地质灾害点的调查,将全区划分为4个地质灾害隐患风险等级的网格区域.在此基础上利用金华中尺度气象资料,采用BP神经网络模型,建立地质灾害细网格预报模型,对该模型进行模拟和预报试验.结果表明,合理的隐患风险等级分区能使预报模型更符合科学规律,而采用分布较细的中尺度资料作为预报因子能进一步提高预报精度.模型的预报结果达到一定的可信度,为防灾减灾工作提供了科学依据.