吉林中部地区一次罕见大暴雨环流背景及触发机制探析

本文利用常规气象观测资料、EC、NCEP2．5°×2．5°的6h分析资料,着重从高层环流特征、水汽条件、热力层结条件、动力触发机制等方面对“7．20”吉林中部地区大暴雨天气过程进行综合分析,结果表明：“7．20”吉林省中部大暴雨的发生与低层冷式切变线移动和发展密切相关,且伴随着中尺度雨团的强烈发展,大暴雨主要产生在中尺度低空急流的左前方、低空冷式切变线右侧以及冷涡的东北象限;副高西侧的西南急流建立起从渤海、黄海到东北地区中部的水汽通道,为这次大暴雨的发生发展提供了暖湿空气和能量;低空急流扰动、中低层切变线长时间停滞、对流层高层强辐散形成的抽吸作用对此次大暴雨过程有明显的触发和增幅作用。     

鲁西南2020年两次区域性大暴雨过程形成机制分析

利用常规地面、高空观测和ERA5再分析数据，对鲁西南2020年7月22日（简称“7〖DK〗·22”过程）和8月6—7日（简称“8〖DK〗·6”过程）两次区域性大暴雨及伴随的短时强降水形成机制诊断分析。结果表明：“7〖DK〗·22”过程是一次地面气旋降水过程，大暴雨主要出现在气旋中心至移向右前部的倒槽内，短时强降水是对流不稳定触发后，惯性不稳定的增强造成。“8〖DK〗·6”过程是一次副高边缘暖区降水过程，大暴雨主要出现在低空急流的前端、地面辐合线附近，短时强降水由对流不稳定的触发和释放造成。“7〖DK〗·22”过程暖湿急流较强，水汽通量散度和动力条件显著强于“8〖DK〗·6”过程，超低空强辐合区、水汽通量散度辐合大值区、水平动能大值区边缘的强锋生区以及湿位涡MPV大值区边缘的|MPV2|小值区对短时强降水的出现区域指示较好。两次过程分析均表明垂直上升运动和深厚湿区的配合对短时强降水的出现时间指示较好。     

韶关一次台风低压大暴雨预报失误的诊断分析

利用NCEP1°×1°的6h再分析资料和气象常规观测资料,对2008年4月20日夜问韶关市一次预报失误的台风低压大暴雨进行诊断分析。结果表明,主要由弱冷空气南下引起的低层强辐合、高层强辐散和强烈深厚的上升运动构成大暴雨的动力条件,低层充足的水汽输送提供了有利的水汽条件;台风“浣熊”登陆减弱后的低压系统和西南引导气流输送不稳定能量到韶关,并得到释放,弱冷空气是动力触发机制;地形对大暴雨的作用主要体现在分布特点和局地变化上。最后分析预报失误的主要原因是对“浣熊”移动路径和弱冷空气作用估计不足,并发现清远站的不稳定能量变化很好地指示了大暴雨的发展过程,可作为韶关暴雨预报的参考经验。     

"05.6"广西持续性大暴雨成因分析

利用常规资料、T 213初始场及6小时预报场资料、卫星云图等资料,用中尺度分析方法,配合诊断分析,对广西“05.6”持续性大暴雨及暴雨落区成因进行了初步探讨,找出其出现大暴雨成因。     

"泰利"台风低压大暴雨过程分析和数值模拟试验

利用NECP1o×1o的6h分析资料和常规观测等资料,对2005年9月2～4日“泰利”台风低压引发的大暴雨过程的不同尺度的天气系统进行了分析,并用非静力中尺度数值预报模式MM5v3.7进行了数值模拟。结果表明,这次大暴雨天气是在和强大稳定的大陆副高与西太平洋副高、中纬度西风带低槽及其引导从地面南下的冷空气、台风低压和台风倒槽、中尺度对流系统相互作用下发生发展的;深厚的强上升运动及其释放的大量潜热是大暴雨维持的重要机制;模式比较成功地模拟了发生在大地形迎风坡下的大暴雨,而对发生在庐山这种范围很小且陡峭地形下的特大暴雨,则模拟降水量偏小。     

“98．6”江西连续大暴雨过程物理量诊断分析

本文通过“98．6”连续大暴雨过程期间物理量场的诊断,分析了热力,水汽,动力等条件对产生连续暴雨的作用,指出暴雨落区与西南低空急流,能量锋区的关系极为密切,水汽输送集中在低层及其以下,最大水汤辐合层出现的925hPa,高层辐散低层辐合的动力特征非常明显。     

"05.6"广西持续性大暴雨成因分析

利用常规资料、T 213初始场及6h预报场、卫星云图等资料,用中尺度分析方法,并配合诊断分析,对广西“05.6”持续性大暴雨成因进行了初步探讨。结果表明:这次过程是在稳定的大尺度环流形势和有利的物理量场条件下发生,是大、中尺度天气系统相互作用的结果,具有典型的中尺度性质,表现出强降雨的不均匀性、突发性和局地性,是中尺度天气系统活动的结果。     

2007年7月川东北连续3场大暴雨过程的诊断分析

利用常规观测资料及NCEP 1°×1° 6h再分析资料,对2007年7月上旬四川东北部连续出现的3场大暴雨过程的环流形势及动力结构、水汽输送和热力不稳定条件进行了诊断分析。结果表明：（1）前2场区域性大暴雨出现在副热带高压和巴尔喀什湖冷涡两个长波系统稳定少动的阻塞环流形势下．第3场局地性大暴雨发生在环流调整过程中,副热带高压快速东撤导致对流云团在东移过程中迅速减弱消亡;（2）暴雨的水汽主要来自南海,低空偏南风急流的维持为连续暴雨提供了源源不断的水汽输送和持续的能量供应,3场暴雨的中心均出现在位于低空急流出口区左侧水汽辐合中心的巴中地区;（3）造成严重洪涝灾害的前2场区域性大暴雨过程期间,从地面到高层形成了“辐合-辐散-辐合-辐散”接力式上下大气运动的动力结构,大气层结处于高能和对流不稳定状态,且有冷空气触发,大暴雨发生在能量锋区偏向暖区一侧。     

“96.8”暴雨分析

１９９６年８月３日－５日，山西省南部和东部出现了暴雨、大暴雨天气，造成严重洪涝灾害。本文对这次暴雨成因进行了探讨。认为，“９６．８”大暴雨过程是在稳定的大心度五流形势下中低纬度系统相互作用的结果。其中，副高稳定形势是产生这场大暴雨的基础；９６０８号台风低压北上为暴雨区提供了充沛水汽和不稳定能量。     

桂林"98.6"连续大暴雨的特征分析

通过对桂林“98.6”连续大暴雨的形势分析,揭示了这次过程的大环流维持机制,暴雨得以维持的主要原因;另外,分析了连续暴雨与低空急流及其非地转风存在的明显内在联系。指出西南涡、低空急流等系统的活动与连续暴雨过程中的雨峰有直接关系。     

Anthropogenic, Climatic, and Hydrologic Trends in the Kosi Basin, Himalaya

A great debate exists concerning theinfluence of land-use and climatic changes onhydrology in the Himalayan region and its adjacentplains. As a representative basin of the Himalayas, westudied basinwide land-use, climatic and hydrologictrends over the Kosi Basin (54,000 km²) in themountainous area of the central Himalayan region. Theassessment of anthropogenic inputs showed that thepopulation of the basin grew at a compound rate ofabout one percent per annum during the past fourdecades. The comparison of land-use data between thesurveys made during the 1960s and 1978–1979 did notreveal noticeable trends in land-use change. Theanalysis of meteorological and hydrological timeseries from 1947 to 1993 showed some increasingtendency of temperature and precipitation. Thestatistical tests of hydrologic trends indicated anoverall decrease in discharge on the Kosi River andits major tributaries. The decreasing trends ofstreamflow were more significant during the low-flowmonths. The statistical analysis of homogeneityshowed that the climatic as well as the hydrologictrends were more localized in nature lacking adistinct basinwide significance.     

基于中心轴线的北太平洋冬季风暴轴分类及其机理研究

利用NCEP/NCAR逐日再分析资料研究了63年（1948～2010年）冬季北太平洋风暴轴的时空演变,提取风暴轴的中心轴线作为研究主体,以风暴轴的经向分布差异为重点,用模糊C均值聚类分析的方法将风暴轴分为平均型、偏北型和偏南型三类,并探讨了各类风暴轴对应的海气异常型及其物理机制。结果表明:（1）三类风暴轴分别显示了风暴轴经向差异的具体物理图像,对应着不同的涡旋移动发展路径,具有明确的天气学意义。通过EOF分解证明本文的分类反映了风暴轴的主要变化特征,物理意义清晰,具有一定的合理性和实用性。（2）三类风暴轴不仅经向差异明显,其北抬南压的纬向位置也存在显著差异,进一步表明该分类方法充分考虑了风暴轴空间分布的经向纬向差异,还揭示了风暴轴多中心的特点。（3）三类风暴轴对应的不同SST异常通过热力过程影响大气的温度场、风场和位势高度场,导致阿留申低压强度位置异常和水平风场异常,进而影响大气斜压性,决定风暴轴的空间分布,是形成不同类型风暴轴的重要原因。     

Climate change,the monsoon,and rice yield in India

Recent research indicates that monsoon rainfall became less frequent but more intense in India during the latter half of the Twentieth Century, thus increasing the risk of drought and flood damage to the country’s wet-season (kharif) rice crop. Our statistical analysis of state-level Indian data confirms that drought and extreme rainfall negatively affected rice yield (harvest per hectare) in predominantly rainfed areas during 1966–2002, with drought having a much greater impact than extreme rainfall. Using Monte Carlo simulation, we find that yield would have been 1.7% higher on average if monsoon characteristics, especially drought frequency, had not changed since 1960. Yield would have received an additional boost of nearly 4% if two other meteorological changes (warmer nights and lower rainfall at the end of the growing season) had not occurred. In combination, these changes would have increased cumulative harvest during 1966–2002 by an amount equivalent to about a fifth of the increase caused by improvements in farming technology. Climate change has evidently already negatively affected India’s hundreds of millions of rice producers and consumers.     

Climatology of Ozone, PAN, CO, and NMHC in the Free Troposphere Over the Southern North Atlantic

Free tropospheric measurements of ozone, peroxyacetylnitrate andprecursors (CO, NMHC) that were made within the framework of the EUROTRACsub-project TOR (Tropospheric Ozone Research) between 1990 and 1995 at theGAW station Izana, Tenerife (28°18N, 16°30W) arediscussed. The average annual cycles reveal the importance of transport fromnorthern mid-latitudes and the role of photo-chemistry. According toair-mass trajectories, which were supplied to us from AEROCE(Atmosphere/Ocean Chemistry Experiment), transport from northernmid-latitudes is associated with high precursor concentrations in winter,whereas ozone concentrations in winter are not much influenced by transportpatterns, suggesting a rather uniform distribution over the northern part ofthe Northern Hemisphere around mean value of 43 ± 5 ppb. In summer,high ozone concentrations of up to 90 ppb are often encountered duringtransport from north, while the levels of precursors are much lower than inwinter, because of photochemical destruction. Trajectories from southerlylatitudes and the Sahara usually have the lowest ozone concentrationsassociated with them.     

中国古诗词中的云雾雨雪

从云雾降水物理学的角度学习和分析了一些中国古诗词。内容有:1）分析和统计了唐诗300首和毛泽东诗词中用到云雾雨雪等字的百分比,其分别占总首数的45%和66%;2）列举和分析了描述自然过程、大气过程有云雨雪等字的诗(词)句;3）从现代科学观出发,分析了在一些古诗词中有关云、雨、霜、露等的理解,并作了一些评述;4）对古诗词中直接描述云、雾、雨、雪的内容进行了评论。       

Windstorm of the eighteenth century in the Czech Lands: course,extent, impacts

Theoretical and Applied Climatology - This paper addresses the course, extent, and impacts of a windstorm that occurred on 20–21 December 1740, in the Czech Lands. The analysis is based on...     

Solar rotation,impulses of the torque in the Sun's motion,and climatic variation

Running variance analysis and maximum entropy spectral analysis applied to Mount Wilson rotation data yield arguments in favor of a connection between variations in the Sun's rotation rate, energetic X-ray flares, and impulses of the torque (IOT) in the Sun's irregular motion about the barycenter of the planetary system. Such IOT, that have been shown to be related to the secular cycle of solar activity and excursions of the Maunder minimum type, also seem to be linked to outstanding peaks in geomagnetic activity, maxima in ozone concentration, incidence of blocking type circulation, as well as rainfall over Central Europe, England/Wales, eastern United States, and India. Statistical tests, that confirm these links, additionally point to IOT connection with temperature in Central Europe and the number of icebergs that pass south of latitude 48° N. IOT relationship with X-ray flares and strong geomagnetic storms was tested in successful long range forecasts.Glossary of Abbreviated Terms A _c Equatorial angular sidereal solar rotation rate corrected for scattered light and averaged over respective Carrington rotations. - c-events See JU-CM-CSc. - CM Center of mass of the solar system. - CS Center of the Sun. - L Change of angular momentum L in the Sun's orbital motion about CM caused by an impulse of the torque (IOT). This change is measured by the time integral of the torque . - df Degrees of freedom. - g-events See JU-CM-CSg. - IOT Impulse of the torque in the Sun's irregular orbital motion about the center of mass of the solar system CM. The intensity of IOT is measured by the change in angular momentum L effected by the impulse. - JU-CM-CS Solar system constellation that is formed when the center of mass CM, the Sun's center CS and the giant planet Jupiter (JU) are in line. JU-CM-CS events initiate impulses of the torque IOT in the Sun's irregular revolution about CM. - JU-CM-CSc JU-CM-CS event that is accompanied with a sharp increase in orbital angular momentum and centrifugal motion of the Sun away from CM. - JU-CM-CSg JU-CM-CS event that goes along with a steep decrease in orbital angular momentum L and centripetal motion of the Sun toward CM due to prevailing gravitation. - L Angular momentum of the Sun's orbital motion around CM. - T Torque, the varying rotary force applied to the Sun in its orbital motion about CM that is equal to the time rate of change of the angular momentum L. - v Running variance: the smoothing technique of running means over two or more consecutive readings is applied to variance, the square of the standard deviation.     

Balance of water,heat, and solutes in the Dnieper-Bug estuary

The balance of water, heat, and solutes in the Dnieper-Bug estuary is estimated using the data of long-term observations (from 1965 to 2011) for solving the practical problems associated with the rational use of water resources in this area.     

Evidence of the terdiurnal,S 3, atmospheric tide in the surface wind field over the ocean

Surface winds were measured from anchored buoys at the corners of a 100-km triangle in the Atlantic ocean for three weeks in September 1972. The measurements were part of the British Royal Society Joint Air-Sea Interaction Project, JASIN-72. Peaks were found at a frequency of 0.125 cph (8-h period) in various wind statistics, indicating the presence of the terdiurnal, S ₃, component of the atmospheric tides that had previously been extensively studied because it is a prominent component in surface air-pressure records.