CLM4.0模式对中国区域土壤湿度的数值模拟及评估研究

本文利用普林斯顿大学全球大气强迫场资料,驱动公用陆面过程模式（Community Land Model version 4.0,CLM4.0）模拟了中国区域1961～2010年土壤湿度的时空变化。将模拟结果与观测结果、美国国家环境预报中心再分析数据（National Centers for Environmental Prediction Reanalysis,NCEP）和高级微波扫描辐射计（Advanced Microwave Scanning Radiometer-EOS,AMSR-E）反演的土壤湿度进行了对比分析,结果表明CLM4.0模拟结果可以反映出中国区域观测土壤湿度的空间分布和时空变化特征,但东北、江淮和河套三个地区模拟值相对于观测值在各层次均系统性偏大。模拟与NCEP再分析土壤湿度的空间分布基本一致,与AMSR-E的反演值在35°N以北的分布也基本一致;从1961～2010年土壤湿度模拟结果分析得出,各层土壤湿度空间分布从西北向东南增加。低值区主要分布在新疆、青海、甘肃和内蒙古西部地区。东北平原、江淮地区和长江流域为高值区。土壤湿度数值总体上从浅层向深层增加。不同深度土壤湿度变化趋势基本相同。除新疆西部和东北部分地区外,土壤湿度在35°N以北以减少趋势为主,30°N以南的长江流域、华南及西南地区以增加为主。在全球气候变暖的背景下,CLM4.0模拟的夏季土壤湿度在不同程度上响应了降水的变化。中国典型干旱区和半干旱区土壤湿度减小,湿润区增加。其中湿润区土壤湿度对降水的响应最为显著,其次是半干旱区和干旱区。     

探测大气温湿廓线的35通道微波辐射计设计原理与特点

总结了自主研制的MWP967KV型地基35通道微波辐射计系统设计原理和主要特点。系统将K、V双频段宽带天线及接收机、宽带调谐本振、温湿压计以及电源模块紧凑集成为一台整机设备。对各传感器的测量输出实时进行一体化综合处理,采用BP神经网络实时反演大气温度、湿度廓线和汽、水总量。廓线的垂直覆盖范围为地表至顶空10km,共划分为58层。辐射计样机于2012年秋冬季节在北京地区开展了为期2个月的观测试验,利用这段时期内的69个探空资料样本对辐射计2个层次的实时观测输出都进行了对比检验,计算了水汽、氧气通道亮温和反演所得大气温湿廓线的平均偏差、均方差以及相关性。结果表明该系统能够满足实时气象监测的需求,达到国际先进水平。     

Zinc and copper bioaccumulation in fish from Laizhou Bay,the Bohai Sea

Abstract Zinc （Zn） and copper （Cu） concentrations were determined in the tissues （muscle, stomach, liver, gills, skin, and gonads） of five commercial fish species （mullet Liza haematocheilus, flathead Platycephalus indicus, mackerel Scomberomorus niphonius, silver pomfret Pampus argenteus, and sea bass Lateolabrax japonicus） from Laizhou Bay in the Bohai Sea. Metal bioaccumulation was highest in the metabolically active tissues of the gonads and liver. Bioconcentration factors for Zn were higher in all tissues （gonads 44.35, stomach 7.73, gills 7.72, liver 5.61, skin 4.88, and muscle 1.63） than the corresponding values for Cu （gonads 3.50, stomach 3.00, gills 1.60, liver 5.43, skin 1.50, and muscle 0.93）. Mackerel tissues accumulated metal to higher concentrations than did other fish species, but bioaccumulation levels were not significantly correlated with the trophic levels of the fish. Zn and Cu concentrations in the tissues were generally negatively correlated with fish length, except for a few tissues of sea bass. Risk assessment based on national and international permissible limits and provisional tolerances for weekly intake of Zn and Cu revealed that the concentrations of these two metals in muscle were relatively low and would not pose hazards to human health.     

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Variability of tropical cyclone in high frequent occurrence regions over the western North Pacific

In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region E), are defined with frequency of TC's occurrence at each grid for a 45-year period(1965–2009), where the frequency of occurrence(FO) of TCs is triple the mean value of the whole western North Pacific. Over the region S, there are decreasing trends in the FO of TCs, the number of TCs' tracks going though this region and the number of TCs' genesis in this region. Over the region P, the FO and tracks demonstrate decadal variation with periods of 10–12 year, while over the region E, a significant 4–5 years' oscillation appears in both FO and tracks. It is demonstrated that the differences of TCs' variation in these three different regions are mainly caused by the variation of the Western Pacific Subtropical High(WPSH) at different time scales. The westward shift of WPSH is responsible for the northwesterly anomaly over the region S which inhibits westward TC movement into the region S. On the decadal timescale, the WPSH stretches northwestward because of the anomalous anticyclone over the northwestern part of the region P, and steers more TCs reaching the region P in the greater FO years of the region P. The retreating of the WPSH on the interannual time scale is the main reason for the FO's oscillation over the region E.     

CFD-based numerical analysis of a variable cross-section cylinder

Using ANSYS-CFX, a general purpose fluid dynamics program, the vortex-induced vibration (VIV) of a variable cross-section cylinder is simulated under uniform current with high Reynolds numbers. Large eddy simulation (LES) is conducted for studying the fluid-structure interaction. The vortex shedding in the wake, the motion trajectories of a cylinder, the variation of drag and lift forces on the cylinder are analyzed. The results show that the vortices of variable cross-section cylinder are chaotic and are varying along the cylinder. In places where cross-sections are changing significantly, the vortices are more irregular. The motion trail of the cylinder is almost the same but irregular. The drag and lift coefficients of the cylinder are varying with the changes of diameters.     

能见度仪故障现象及维护探讨

通过对前向散射能见度仪常见故障的现象有数据偏小、偏大、跳变及不变,针对故障现象分析,找出数据波动的原因,提出具体的处理方法,供观测员在实际工作中参考,使能见度仪更好的运行。     

上思县油茶栽培气候生态条件分析

通过对上思县及全国其它适宜种植区的油茶栽培中油茶开花授粉、果实膨大、油脂积累等重要生长发育期的气象条件分析,找出上思县适宜发展油茶种植的科学依据,为当地发展油茶业提出建议,为当地林业可持续发展提供参考。     

百色双套自动气象站雷击故障维修的方法

通过对百色双套自动气象站遇到历史罕见的强雷暴袭击出现故障维修,摸索出了检修双套新型自动站的通信、电源供应、主机HY3000、接口RS232、分采仪器等模块的方法,供同行借鉴.