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Lamb-Jenkinson环流客观分型方法及其在中国的应用 总被引：3，自引：0，他引：3
介绍了Lamb-Jenkinson客观环流分型方法.利用1948年1月1日-2004年12月31日的NCEP逐日平均海平面气压资料,计算了中国16个区逐日的6个环流指数及相应的环流分类,分析了中国各区域不同季节各种环流类型出现的频率及其变化特征.结果表明,该方法在我国大部分地区适用,虽然在西部高海拔地区的海平面气压可能有订正误差,但该方法是可行的.对1958-2004年以来3个主要环流指数的线性趋势分析显示,华北及河套至内蒙古中西部地区夏季的经向风指数和纬向风指数下降明显,涡度指数也有明显的下降,表明控制上述地区的高值系统有增多趋势,而准地转西南风减弱,这可能是造成这些地区干旱化的重要环流背景.对冬季而言,我国东北、华北和新疆北部等地区的纬向风指数上升明显,表明我国北部地区冬季的近地层西风有加强的趋势,这与近年来这些地区冬季气温显著升高有密切关系. 相似文献
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引言:最近十年来國内的氣象事業在高空探測方面發展得相當可觀。尤其測風氣球觀測站設立得最多,主要的原因是國内航空事業的進步。航空事業愈進步,牠所需要的氣象資料愈迫切。七七事變未發生以前,國内幾個有名的航空公司在其航線中主要的起落地點,曾設立幾個測風氣球觀測站,其中有觀測時間繼續了五,六年之久的。這種記錄相當可貴,而且似乎還很少人用牠来作過綜合的統計研究。中央研究院氣象研究所在南京,北平,西安,青岛觀象台在靑島,外人在上海與香港,也有較長時期的測風氣球記錄。那些記錄已經多人利用作過各方面的研究。研究結果散見國内外各氣象刊物。七七事變以来,由於空軍方面的需耍,在内地設立了不少的測風氣球 相似文献
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1引言自动站的设备大都是采用半导体器件和集成电路,这些设备普遍存在着绝缘强度低、过电压和过电流耐受能力差、对电磁干扰敏感等弱点,并且都分布在不同的地理环境和气候环境中,在运行过程中较容易遭受雷电的侵袭,雷电过电压、过电流和脉冲电磁场的侵入将会严重影响了自动站设备的正常运行[1]。本文对照防雷设计规范和应用电磁兼容的原理,对自动站防雷技术应注意的几个问题作初步探讨。 相似文献
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在刚刚过去的2006年,是“十一五”规划的开局之年,是新农村建设的起步之年,也是黑龙江省全面建设小康社会发展进程中的重要一年。农业、农村经济持续快速发展,粮食总产量再创历史新高。农民收入连续大幅度增长。结构调整进一步深化,农村改革进一步推进,全省农村呈现出心气顺、尽头足、干群关系和谐稳定的良好局面。这些成绩当中凝聚着全省气象战线广大干部职工做出的重要贡献。过去的一年全省气象工作有了长足的发展,最重要的是国务院下发了《关于加快气象事业发展的若干意见》,省政府也提出具体意见,气象战线的同志们认真学习贯彻国务院的文件和省政府的意见,做了大量卓有成效的工作,气象预测预报准确,提出的对策、措施、建议很及时、很有建设性,气象服务的领域不断拓宽,从对生产服务更多的转向为人民生活服务,得到了人民的普遍好评。 相似文献
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冬春季江苏沿海大风的特征 总被引：7，自引：0，他引：7
利用江苏2005-2006年460个自动站和加密站的风速资料,分析了2005-2006年冬春季发生的大风过程,研究发现冬春季沿海大风多由强冷空气引发,并具有一定的间断性、持续性、突发性和阵性特点,并对典型过程的阵性特征进行了分析.发现冷空气的入侵促使地面风场发展,大风u、v分量的变化与旋转系数具有很好的相关性,旋转系数的逐时波动与v分量的波动基本呈同位相变化趋势,而其与u分量的波动则有反位相关系;在冷空气影响前后,这样的相关特征始终维持. 相似文献
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樊纲 《气候变化研究进展》2012,(4)
“在世界动荡的经济中,寻找中国继续发展的动力。毫无疑问,就目前来讲,非常重要的一个动力,就是改革,就是制度的突破。”中国改革研究基金会理事长樊纲在12月12日召开的“2011CCTV全球财经论坛”上再次发出呼吁,并就包括所有制和企业制改革在内的四个方面进行了进一步的阐述。 相似文献
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IPCC特别报告SRCCL关于气候变化与粮食安全的新认知与启示 总被引：3，自引：0，他引：3
气候变化对粮食安全的影响是广泛的,不但影响粮食产量和品质,还会影响到农户的生计以及农业相关的产业发展等;而粮食系统在保障粮食安全的同时,又会产生一系列的环境问题,其中农业源温室气体（GHG）的排放加剧全球变暖。IPCC在2019年8月份发布的《气候变化与土地特别报告》（SRCCL）,从粮食生产、加工、储存、运输及消费的各个环节评估气候变化对粮食安全的影响及粮食系统的温室气体排放对气候系统的影响;系统梳理粮食系统供给侧和需求侧的适应与减缓措施、适应与减缓的协同和权衡问题,以及气候变化条件下保障粮食安全的政策环境等。SRCCL评估结论认为,由于大量施用氮肥和消耗水资源,目前粮食系统GHG排放占全球总排放的21%~37%;农业和粮食系统是全球应对气候变化的重要方面,供给侧和需求侧的综合措施可以减少食物浪费、减少GHG排放、增加粮食系统的恢复力。未来工作的重点应丰富和扩展气候变化影响评估内容,量化适应效果,加深对适应、减缓及其协同和权衡的科学认知,大力加强应对气候变化能力建设。 相似文献
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Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms. 相似文献
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Hainan, an island province of China in the northern South China Sea, experienced two sustained rainstorms in October2010, which were the most severe autumn rainstorms of the past 60 years. From August to October 2010, the most dominant signal of Hainan rainfall was the 10–20-day oscillation. This paper examines the roles of the 10–20-day oscillation in the convective activity and atmospheric circulation during the rainstorms of October 2010 over Hainan. During both rainstorms,Hainan was near the center of convective activity and under the influence of a lower-troposphere cyclonic circulation. The convective center was initiated in the west-central tropical Indian Ocean several days prior to the rainstorm in Hainan. The convective center first propagated eastward to the maritime continent, accompanied by the cyclonic circulation, and then moved northward to the northern South China Sea and South China, causing the rainstorms over Hainan. In addition, the westward propagation of convection from the tropical western Pacific to the southern South China Sea, as well as the propagation farther northward, intensified the convective activity over the northern South China Sea and South China during the first rainstorm. 相似文献
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Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d. 相似文献
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Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region. 相似文献
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By using the gauged rainfall in 160 stations within mainland China and the NCEP/NCAR reanalysis data, the impacts of anomalous SST in Kuroshio and its extension on precipitation in Northeast China were investigated. The results show that a difference in the meridional circulation such as the East Asia/Pacific teleconnection pattern(EAP)may be responsible for the difference in rainfall between 1998 and 2010. In comparison with 1998, the anomalous meridional circulation pattern in 2010 shifted northeastward, and then the western subtropical high, the mid-latitudinal trough and the northeastern Asia blocking high also shifted northeastward, causing intensified convergence of the cold and warm air masses at the southern region and thus more rainfall in the southwestern region and less in the northwestern region. In 1998, the anomalous cyclone, one component of the meridional pattern, located at the Songhuajiang-Nengjiang River basin, resulted in more rainfall in the majority of the area. The results of observation and the model show that the difference in SSTA in Kuroshio and its extension under the background of different El Ni觡o events is the key point:(1) The anomalous warmth moved westward from the mid-Pacific to the east of the Philippine Sea during the central event, which led the heat resources shifting to the northeast in 2010; subsequently, a shift occurred to the north of the anomalous ascent and decent, followed by a warm SSTA in the region of Kuroshio's extension in 2010 and Kuroshio in 1998.(2) The warm SSTA in the Kuroshio extension causing the Rossby wave activity flux strengthened in 2010, and then the westerly jet shifted northward and extended eastward. A warm SSTA in Kuroshio and cold SSTA in its extension in 1998 caused the westerly jet to shift southward and weaken. As a result,the anomalous anticyclone and cyclone shifted northward in 2010, and the blocking high also shifted northward. 相似文献
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Connections between the Eurasian teleconnection and concurrent variation of upper-level jets over East Asia 总被引：3，自引：0，他引：3
The variation of the East Asian jet stream(EAJS) associated with the Eurasian(EU) teleconnection pattern is investigated using 60-yr NCEP–NCAR daily reanalysis data over the period 1951–2010. The EAJS consists of three components: the polar front jet(PFJ); the plateau subtropical jet(PSJ); and the ocean subtropical jet(OSJ). Of these three jets over East Asia,the EU pattern exhibits a significant influence on the PFJ and OSJ. There is a simultaneous negative correlation between the EU pattern and the PFJ. A significant positive correlation is found between the EU pattern and the OSJ when the EU pattern leads the OSJ by about 5 days. There is no obvious correlation between the EU pattern and the PSJ. The positive EU phase is accompanied by a weakened and poleward-shifted PFJ, which coincides with an intensified OSJ. A possible mechanism for the variation of the EAJS during different EU phases is explored via analyzing the effects of 10-day high-and low-frequency eddy forcing. The zonal wind tendency due to high-frequency eddy forcing contributes to the simultaneous negative correlation between the EU pattern and the PFJ, as well as the northward/southward shift of the PFJ. High- and low-frequency eddy forcing are both responsible for the positive correlation between the EU pattern and the OSJ, but only high-frequency eddy forcing contributes to the lagged variation of the OSJ relative to the EU pattern. The negative correlation between the EU pattern and winter temperature and precipitation anomalies in China is maintained only when the PFJ and OSJ are out of phase with each other. Thus, the EAJS plays an important role in transmitting the EU signal to winter temperature and precipitation anomalies in China. 相似文献
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A one-dimensional, time-dependent cloud model with parameterized microphysics is used to investigate the processes which control the rainout and washout of soluble gases from warm, precipitating stratiform clouds. Calculations are presented simulating the distributions of soluble species within and below the cloud layer and in the precipitating raindrops as a function of time and species' solubility. Our calculations indicate that for species with low solubility, wet removal processes are relatively slow and thus do not significantly affect the species' gas-phase abundance. As a result, the removal of low-solubility species by rainout and washout is controlled by thermodynamic processes with the concentration of the species in cloud and rainwater largely determined by the species' solubility. For highly soluble species on the other hand, dissolution into cloud droplets and removal in rain is quite rapid and the abundance of highly soluble species within and below the cloud falls rapidly as soon as the precipitation begins. Because of this rapid decrease in concentration, we find that for highly soluble species: concentrations in cloud droplets near the cloud base can exceed that of raindrops by factors of 2 to 10; washout can dominate over rainout as a removal mechanism; and that, after an extended period of rainfall, the rate of removal becomes independent of the microphysical properties and rainfall rate of the cloud and is controlled by the rate of transport of material into the precipitating column by horizontal advection. 相似文献
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The Fe(II)/Fe(III)-partition in cloudwater samples collected during two field campaigns is evaluated. It turned out that the simultaneous occurrence of complexing and reducing substances in the atmosphere and the cloud processing increase the solubility of iron compounds present in aerosol particles. A correlation between the concentration of iron(II) in the liquid phase and the intensity of the solar irradiation was observed for most of the cloudwater samples. This could be due to the fact that both the photochemical reduction of the iron(III) complexes and the photochemical reductive dissolution of iron(III)(hydr)oxides are depending on the pH-value. Iron(II) seems to be oxidised back to iron(III) preferably by hydrogen peroxide during the night. Positive correlations were received e.g. between the concentration of dissolved iron and the concentration of oxalate and between the percentage of iron(III) and the concentration of hydrogen peroxide. A negative correlation was found e.g. between the concentration of dissolved iron and the pH-value. The uncertainty of the whole process of sampling and analysis was investigated and the conformity of the results was satisfying considering the sometimes difficult conditions during a field campaign. 相似文献
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This paper reviews briefly advances in recent research on monsoon by Chinese scholars, including primarily： （1） the establishment of various monsoon indices. In particular, the standardized dynamic seasonal variability index of the monsoon can delimit the geographical distribution of global monsoon systems and determine quantitatively the date of abrupt change in circulation. （2） The provision of three driving forces for the generation of monsoon. （3） The revelation of the heating-pump action of the Tibetan Plateau, which strengthens southerlies in the southern and southeastern periphery of the Plateau and results in a strong rainfall center from the northern Bay of Bengal （BOB） to the Plateau itself. （4） Clarification of the initial onset of the Asian Summer Monsoon （ASM） in the BOB east of 90°E, Indochina Peninsula （ICP） and the South China Sea, of which the rapid northward progression of tropical convection in the Sumatra and the rapid westward movement of the South Asia High to the Indochina Peninsula are the earliest signs. （5） The provision of an integrated mechanism for the onset of the East Asian Summer Monsoon （EASM）, which emphasizes the integrated impact of sensible heat over Indian Peninsula, the warm advection of the Tibetan Plateau and the sensible heat and latent heat over the Indochina Peninsula on the one hand, and the seasonal phase-lock effect of the northward propagation of low frequency oscillation on the other. （6） The revelation of the ＂planetary-scale moisture transport large-value band＂ from the Southern Hemisphere through to the Asian monsoon region and into the North Pacific, which is converged by several large-scale moisture transport belts in the Asian-Australian monsoon regions and whose variation influences directly the temporal and spatial distribution of summer rainfall in China. （7） Presenting the features of the seasonal advance of the EASM, the propagation of intraseasonal oscillation, and their relationship with rainfall in Ch 相似文献
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l. IntroductionModel simulation of soll physical properties is very 1mportant for climate studies becauseof the role they play in different interaction processes with the atmosphere. One of the mostwidespread studies is the implementation of soil models 1n General Circulation Models(GCMs); previous studies showed, in fact, that climate simulat1ons are sensitive to theparameterization of the energy and mass fluxes at the land surface (V1terbo, l995; Beljiaars etal., l996; Dolman et al., l997… 相似文献