舟山冬季暴雨的特征

文章分析了冬季暴雨发生时的环流形势和物理量场分布特征,揭示了冬季暴雨的发生与厄尔尼诺现象有着一定的相关。同时,分析了单站要素的变化,为以后的冬季暴雨预报提供参考。     

Climatological Characteristics of the East Asian Winter Monsoon Simulated by CWRF Regional Climate Model

Based on the ERA-Interim atmospheric reanalysis data from the European Medium-Term Weather Forecast Center from 1979 to 2016 and the ERSSTv4 sea surface temperature data from the US National Oceanic and Atmospheric Administration, the regional climate model CWRF was used to simulate the climate characteristics in East Asia. The results show that the CWRF model can well reproduce the average characteristics of the East Asian winter monsoon circulation, including the location and intensity of the low-level continental cold high pressure and variation characteristics of wind field in high and low levels. The occurrence area and frequency of the north wind in the simulation and the reanalysis data were further calculated and compared. It is shown that they are basically consistent. The distribution of air temperature and precipitation over China are well represented by the model. The water vapor transport is also in good agreement with the reanalysis data. The water vapor from the Bay of Bengal plays a vital role in the precipitation over South China. The simulation results of apparent heat source and apparent moisture sink show that the model can well simulate the thermal difference between the East Asian continent and the adjacent sea area. The analysis results indicate that CWRF model has the ability to simulate the main characteristics of the East Asian winter monsoon.     

太湖生态脆弱性特征与消除对策的初步探讨

本文研究了Ｈｇ＾２＋,Ｃｄ＾２＋对痧生经济植物莼菜冬芽茎叶叶绿素含量,叶绿素ａ／ｂ值,可溶性蛋白含量,Ｏ＾－２含量以及活笥氧清除系统活性（ＳＯＤ,ＣＡＴ,ＰＯＤ）的影响,实验结果表明：叶绿素含量,叶绿素ａ／ｂ值、可溶性蛋白含量随着Ｈｇ＾２＋,Ｃｄ＾２＋处理浓度的加大呈下降趋势;     

华南冬季准静止锋年际变异特征及其对东亚气候的影响

基于JRA55再分析资料、观测的降水量和海表温度等数据,利用统计诊断方法分析了华南冬季气候准静止锋的主要变异特征,并探讨了其与环流、海温及东亚气候的联系。华南冬季气候准静止锋的主要变异模态表现为强度变异模态和经向位置变异模态,它们以年际变化为主。类东部型ENSO海温异常及热带中西印度洋海温异常对华南准静止锋强度的年际变异有显著影响;而类中部型ENSO海温异常型显著影响着华南气候准静止锋的南北位置。华南冬季准静止锋的强度变异对东亚副热带地区的降水、以及我国东部内陆地区的近地面气温有显著影响;华南冬季准静止锋南北位置变异则显著影响我国江淮流域降水、以及我国华南至东南沿海一带的近地面气温。华南冬季准静止锋的强度变异模态对东亚的降水和近地面气温的影响范围较位置变异模态都要大。     

径流量干旱指数在河西走廊灌区的应用

利用径流量干旱指数以及河西地区的酒泉、张掖和武威的春小麦单产资料,探讨干旱指数的等级与去趋势春小麦产量之间的关系.研究结果表明,径流量干旱指数与河西灌溉区春小麦气候产量呈反位相的变化趋势.因此,可利用径流量干旱指数的变化来预测该地区未来春小麦产量变化趋势.     

East Asia winter monsoon variations on a millennial time‐scale before the last glacial–interglacial cycle

Grain size and magnetic susceptibility measurements on samples from a typical loess–palaeosol sequence on the central Chinese Loess Plateau are used to reconstruct the Pleistocene East Asian monsoon climate. The coarse‐grained fraction, i.e. the weight percentage > 30 μm of the bulk grain‐size distribution, is used as a sensitive proxy index of the East Asia winter monsoon strength. On the basis of an absolute time‐scale, time‐series variations of this proxy show that winter monsoon strengths varied on millennial time‐scales during the periods 145–165, 240–280, 320–350, 390–440, 600–640, 860–890, 900–930 and 1330–1400 kyr BP. The wavelength of these climatic oscillations varied between 1.89 and 4.0 kyr, as is shown by spectral analysis using the multitaper method. Although numerical simulation experiments show that high frequencies also can arise from measurement errors in the grain‐size analysis, the frequencies prove to be sufficiently stable when the spectral analysis is repeated with a different number of tapers. For the time being, we do not correlate these climatic oscillations with palaeoclimatic records in the North Atlantic deep‐sea sediments because both time‐scales need to be further improved. Our data, however, certainly demonstrate that millennial‐scale East Asian winter monsoon variations in the last 1.4 million years can be detected from terrestrial loess records. Copyright © 1999 John Wiley & Sons, Ltd.     

冬季大风影响下的渤黄海水交换特征

利用ROMS海洋数值模式对2006年冬季渤黄海的海洋动力环境进行模拟,基于温度、盐度模拟结果,使用谱混合模型进行水团分析,定义了渤海海峡地区的水交换区。并进一步讨论了冬季大风事件对水交换区的影响,给出了冬季大风影响下的渤黄海水交换特征。研究得出,冬季的黄海水团以“舌”形分布于渤海海峡地区,水交换区则表现为沿“舌”形边缘呈带状分布,具有西北——东南的走向趋势,并且在“舌”尖处的水交换面积最大。通过缩小研究范围,发现位于黄海最北部的沿岸海域并不参与渤黄海之间的水体交换。最后研究发现,冬季大风事件对渤海水交换具有促进作用,具体表现为：大风过程使黄海暖流对渤海的入侵更加深入,水交换区向渤海方向伸展,南部的水交换带变宽,河流径流进入渤海后与渤海水的混合区加大,并发生北移。     

2009年冬季南海北部浮游植物粒度分级生物量和初级生产力

2009年2月在南海北部海域现场观测粒度分级叶绿素a质量浓度和初级生产力(PP)的分布。结果表明,调查海域水柱平均叶绿素a质量浓度的变化范围为0.11～8.37 mg/m³,平均为(1.28±2.23) mg/m³,高值区出现在珠江口及近岸海域;初级生产力的范围为344.8～1 222.5 mgC/(m²·d),平均为(784.2±351.4) mgC/(m²·d),高值区位于近岸及陆架海域。浮游植物粒度分级测定结果表明,在生物量较高的近岸海域,叶绿素a的粒级结构以小型浮游植物占优势,其贡献率为40.9%,微型和微微型浮游植物对总叶绿素a的贡献率分别为34.6%和24.5%;而在生物量较低的陆坡和开阔海域,各粒级浮游植物对叶绿素a的贡献率由大到小依次为微微型浮游植物(78.9%),微型浮游植物(17.2%)和小型浮游植物(3.9%)。相关性分析结果表明,调查海域分级叶绿素a的区域化分布特征与洋流运动下营养盐的分布密切相关,同时叶绿素a又高度影响着此区域PP的分布。此外,我们将调查海域实测所得浮游植物最佳光合作用速率与采用垂向归一化初级生产力模型估算的数据进行对比,发现后者明显低于前者,这说明通过水温估算最佳光合作用速率的算法在冬季南海北部可能存在低估。     

网箱养殖大黄鱼越冬期间脂肪酸的相对含量变化

利用气-质法(GC-MS)对越冬期间海水平均温度在20,16,12,10和8 ℃条件下的2龄大黄鱼肌肉和肝脏组织中脂肪酸组成及相对含量进行分析,结果表明:随着海水水温的降低,机体会增加不饱和脂肪酸含量,尤其是EPA[C20:5(n-3)],EPA在肌肉中的含量从20 ℃时5.71%增至8 ℃时8.06%,在肝脏中从20 ℃时6.76%增至8 ℃时8.44%。由此可见,在越冬禁食条件下,大黄鱼机体通过自身的脂肪酸动态转化和代谢,减少饱和脂肪酸含量,而增加不饱和脂肪酸含量,以此增加膜的流动性,抵御寒冷。     

冬季气候变暖对山西省冬小麦可种植区的影响

基于山西省境内较为均匀分布的70 个地面气象观测站1970-2012 年冬季逐日气温资料,采用线性倾向估计法分析了负积温、最冷月平均气温和年极端最低气温的变化特征,采用累积距平法确定其突变点,以突变点为界分为前后2 个时间段,依据前后时间段等值线的变化分析冬季气候变暖对山西省冬小麦可种植区的影响。结果表明：山西省负积温呈现显著减少趋势（通过了α=0.01 的显著检验）,最冷月平均气温和年极端最低气温呈现不显著升高趋势;突变后,负积温平均减少了103.4℃,最冷月平均气温和年极端最低气温分别升高了0.8℃和0.7℃;在3 个指标中,决定山西省冬小麦能否种植的关键因子是负积温和年极端最低气温,最冷月平均气温的影响较小;冬季气候变暖后,平均状况下,冬小麦可种植区域面积扩大了约2.9×10⁶ hm²,扩大52%,80%保证率下,冬小麦种植面积扩大了约2.3×10⁶ hm²,扩大79%。