DIAGNOSTIC INVESTIGATION OF SIMULATION BIAS WITH THE GRAPES-MESO MODEL FOR A TORRENTIAL RAIN CASE     

孔荣  王建捷 《热带气象学报(英文版)》2007,13(1):69-72

In this paper, the numerical simulation bias of the non-hydrostatic version GRAPES-Meso (Mesoscale of the Global and Regional Assimilation and Prediction System) at the resolution of 0.18o for a torrential rain case, which happened in May 31st to June 1st 2005 over Hunan province, are diagnosed and investigated by using the radiosondes, intensive surface observation, and the operational global analysis data, and the sensitivity experimental results as well. It is shown in the result that the GRAPES-Meso could reproduce quite well the main features of large-cale circulation and the distribution of the accumulated 24h precipitation and the key locations of the torrential rainfall are captured reasonably well by the model. However, bias exist in the simulation of the mesoscale features of the torrential rain and details of the relevant systems, for example, the simulated rainfall that is too earlier in model integration and remarkable underprediction of the peak value of rainfall rates over the heaviest rainfall region, the weakness of the upper jet simulation and the overprediction of the south-west wind in the lower troposphere etc. The investigation reveals that the sources of the simulation bias are different. The erroneous model rainfall in the earlier integration stage over the heaviest rainfall region is induced by the model initial condition bias of the wind field at about 925hPa over the torrential rainfall region, where the bias grow rapidly and spread upward to about 600hPa level within the few hours into the integration and result in abnormal convergence of the wind and moisture, and thus the unreal rainfall over that region. The large bias on the simulated rainfall intensity over the heaviest rainfall region might be imputed to the following combined factors of (1) the simulation bias on the strength and detailed structures of the upper-level jet core which bring about significant underpredictions of the dynamic conditions (including upper-level divergence and the upward motion) for heavy rainfall due to unfavorable mesoscale vertical coupling between the strong upper-level divergence and lower-level convergence; and (2) the inefficient coupling of the cumulous parameterization scheme and the explicit moisture in the integration, which causes the failure of the explicit moisture scheme in generating grid-scale rainfall in a certain extent through inadequate convective adjustment and feedback to the grid-scale. In addition, the interaction of the combined two factors could form a negative feedback to the rainfall intensity simulation, and eventually lead to the obvious underprediction of the rainfall rate.  相似文献   

基于RS&GIS的西部干旱区植被覆盖变化的研究     

穆增光  孔金玲 《地理空间信息》2007,5(5):66-69

以新疆阜康地区为研究区,利用遥感和GIS技术及数理统计学方法,利用ERDAS软件,通过对70年代MSS和2000年ETM影象的几何校正、图象增强、应用目视解译方法,在地理信息系统软件ArcGIS中编制两期生态景观图,利用矢栅转换和叠置功能来研究土地及植被类型的面积及空间分布状况在两期图中的变化,并通过土地利用与土地覆被变化来研究70年代到2000年西部干旱区土地及植被类型变化过程和趋势。  相似文献   

纳米级微粒地球化学测量中异常重现性研究     

刘应汉  赵传东  孔牧  张华  张勤  任天祥 《物探化探计算技术》2007,(Z1)

纳米级微粒测量是寻找隐伏矿的新方法,选取实地模拟实验和在已知隐伏矿区,利用液态捕集剂和等离子体质谱分析测试样品,进行重复测量试验,研究结果表明,不同成矿元素,在地表形成异常的运移富集速率不同,其运移速率主要取决于纳米级微粒本身的地球化学性质,地下上升气流、断裂等裂隙有利于微粒的上升运移富集;纳米级微粒地球化学重复测量时,异常可具有良好的重现性,但异常重现较常规气体缓慢,通常需要2~3个月。  相似文献   

气候波动和土地覆盖变化下的黄河源区水资源预测   总被引：8，自引：0，他引：8  

车骞  王根绪  孔福广  陈玲  姜秀娜 《水文》2007,27(2):11-15

以黄河源区为研究对象,以分布式水文模型SWAT为研究工具,建立不同气候波动和土地覆盖变化情景,模拟和预测未来水资源的变化。针对黄河源区特殊的下垫面条件,着重冰雪和冻土的水文过程调试,对模拟结果的评价显示,SWAT模型能够较好地模拟黄河源区的水资源变化。不同情景下演算得出的水资源量数据可信,具有一定的实用意义,随着认识的深入和模型结构以及参数的优化,模型在寒区水资源研究和管理中会发挥更大作用。  相似文献   

长江下游地区中生代构造活动与岩浆作用     

翁世劼  孔庆寿 《地球学报》1981,3(1):1-20

<正> 一、地质发育概况 长江下游地区在地质发育进程中历经了多次构造旋回,经受多期构造作用的迭加和改造。（一）前寒武纪；（二）古生代；（三）中生代。  相似文献   

Spatial Variation of Dissolved Organic Carbon in Soils of Riparian Wetlands and Responses to Hydro-geomorphologic Changes in Sanjiang Plain,China     

XI Min  KONG Fanlong  LYU Xianguo  JIANG Ming  LI Yue 《中国地理科学(英文版)》2015,(2):174-183

Spatial variation of dissolved organic carbon(DOC) in soils of riparian wetlands and responses to hydro-geomorphologic changes in the Sanjiang Plain were analyzed through in situ collecting soil samples in the Naoli River and the Bielahong River. The results showed that the average contents of DOC for soil layer of 0–100 cm were 730.6 mg/kg, 250.9 mg/kg, 423.0 mg/kg and 333.1 mg/kg respectively from riverbed to river terrace along the transverse directions of the Naoli watershed. The content of the soil DOC was the highest in the riverbed, lower in the high floodplain and much lower in the river terrace, and it was the lowest in the low floodplain. The difference in the content and vertical distribution of DOC between the riverbed and the three riparian wetlands was significant, while it was not significant among the low floodplain, the high floodplain and the river terrace. The variability of soil DOC was related to the hydrological connectivity between different landscape position of the riparian wetlands and the adjacent stream. Extremely significant correlations were observed between DOC and total organic carbon(TOC), total iron(TFe), ferrous iron(Fe(II)) whose correlation coefficients were 0.819, –0.544 and –0.709 in riparian wetlands of the Naoli River. With the increase of wetland destruction, soil p H increased and soil DOC content changed. The correlation coefficients between soil DOC and TOC, TFe, Fe(II) also changed into 0.759, –0.686 and –0.575 respectively in the Bielahong River. Under the impact of drainage ditches, the correlations between soil DOC and TFe, Fe(II) were not obvious, while the soil p H was weakly alkaline and was negatively correlated with soil DOC in the previous high floodplain. It indicates that riparian hydro-geomorphology is the main factor that could well explain this spatial variability of soil DOC, and the agricultural environmental hydraulic works like ditching also must be considered.  相似文献   

山东半岛北部滨浅海区表层沉积物铝物源鉴别     

徐刚  刘健  裴绍峰  孔祥淮  胡刚  高茂生 《海洋学报(英文版)》2015,34(12):147-153

Surface sediment samples in the near shore area of the north Shandong Peninsula are collected for grain size and element analyses. The results indicate that the surface sediments in the study area are primarily composed of the silt-sized components similar to the Huanghe River. The total concentration of aluminum varies from 5.57% to7.37%(average(6.33 ± 0.40)%), and its spatial distribution is mainly controlled by the grain size. Correlations between the ratio of aluminum to titanium concentration and aluminum concentration, titanium concentration and the mean grain size indicate that aluminum in the near shore surface sediments is affected majorly by the terrigenous source, and partially by the anthropogenic source. The ratios of aluminum to titanium concentrations are larger than the background value of loess matter at some stations due to the existence of excess aluminum associated with human activities. Thus, the sources of aluminum should be identified firstly when aluminum is used as an index of terrigenous matter even in the near shore area dominated by terrigenous deposits.  相似文献   

长牡蛎F3 代快速生长选育群体生长特性的研究   总被引：1，自引：0，他引：1  

孔宁  李琪  丛日浩  王庆志  孔令锋 《海洋科学》2015,39(3):7-11

采用模型拟合方法研究了长牡蛎(Crassostrea gigas)F3代快速生长选育群体不同时期各生长性状的发育规律。结果表明,长牡蛎幼虫期壳高(SH)、壳长(SL)对日龄(t)的回归遵循Logistic模型,生长方程分别为SH=455.612/(1+9.500e-0.142t),R2=0.999;SL=462.476/(1+8.026e-0.108t),R2=0.996。幼虫期壳高与壳长成直线相关,回归方程为SL=0.76SH+18.82,R2=0.994。长牡蛎养成期各生长性状呈现明显的季节变化,壳高(SH)、壳长(SL)、壳宽(SW)和总质量(TW)对月龄(X)的多项式回归方程分别为SH=-0.0297X4+1.0365X3-12.0220X2+57.6500X-68.9260,R2=0.985;SL=-0.0173X4+0.5893X3-6.5702X2+30.2420X-34.4150,R2=0.986;SW=-0.0068X4+0.2620X3-3.2806X2+16.9170X-22.1410,R2=0.956;TW=-0.0219X4+0.8234X3-10.1680X2+50.7040X-85.4110,R2=0.972。壳高、壳长、壳宽与总质量均呈幂函数相关,回归方程分别为SH=23.645TW0.3213,R2=0.998;SL=12.337TW0.3776,R2=0.995;SW=6.611TW0.3589,R2=0.981。  相似文献   

利用不同盐度诱导长牡蛎三倍体的研究     

于瑞海  王昭萍  孔静  沈建平  左仔荣 《中国海洋大学学报(自然科学版)》2015,45(1):26-29,82

采用低盐度(4、6、8、10、12、14、16)和高盐度(40、45、50、55、60、65、70)在40%~50%受精卵出现第一极体时处理10和15min,进行长牡蛎三倍体的诱导。在低盐度诱导三倍体实验中,随着盐度降低,D型幼虫孵化率逐渐降低,处理10和15min的卵裂率差异显著(P0.05),孵化率差异不显著(P0.05)。当盐度为8时,处理受精卵10与15min,三倍体诱导率最高分别可达84.4%和91.0%,两处理组三倍体诱导率差异显著(P0.05)。在高盐度诱导三倍体实验中,随着盐度升高,D型幼虫孵化率逐渐降低,处理10和15min的卵裂率和孵化率均差异显著(P0.05)。当盐度为55时,处理受精卵10min,三倍体诱导率最高为80.3%;当盐度为60时,处理受精卵15min,三倍体诱导率最高为97.1%,两处理组三倍体诱导率差异显著(P0.05)。研究发现,在盐度为8和60条件下,40%~50%的受精卵出现第一极体时,处理15min,长牡蛎三倍体诱导率最高。  相似文献   

基于主成分分析的相对重力观测零漂和固体潮提取     

于红娟  郭金运  李九龙  穆大鹏  孔巧丽 《大地测量与地球动力学》2015,35(5):906-910

利用主成分分析PCA提取2014-08-15~23CG-5相对重力仪静态相对观测的零点漂移和固体潮。结果显示,PCA提取的零点漂移值与最小二乘线性拟合结果非常一致,其差仅在10-2μGal/d量级;PCA估算的固体潮值与CG-5重力仪内部软件提供的固体潮模型计算值统计结果基本一致,两者之差均小于8μGal,均方根均小于5μGal。  相似文献