生态环境退化对兰州城市气候的影响

目的为了有效地利用兰州地区的气候资源,减少因生态环境退化而对兰州地区气候产生的负面影响,为兰州地区社会经济发展服务.方法查阅历史文献和实际考察,将兰州地区气候现状与历史时期的变化加以对比,剖析其发生变迁的原因.结果由于对森林的乱砍滥伐,对草原的不合理开垦以及透支使用,使兰州地区的生态环境遭到毁灭性的破坏,气候干旱化加剧,水旱灾害频繁发生.结论结合兰州地区的实际,采取有力的保护措施,对尚未遭到严重破坏的生态环境加以保护;对生态环境已经遭到严重破坏的地区,依靠自然力量或采取人工措施使生态环境得到改善.     

Anthropogenic climate change revealed by coral gray values in the South China Sea

The authors analyze the coral growth band from a colony in the northwestern South China Sea. The coral growth band can provide comprehensive environmental information on climate. The trend from the two-century-long annual density of the coral is in a good agreement with that of the global CO2 concentration. Both trends were small prior to the end of the 19th century; after that, trends became clear, more so from the 1960s to the 1990s (the end of the coral record). The overall coral density shows a steady d...     

入世对湖北省产业投资环境的影响

认为湖北省投资环境在入世后面临机遇与挑战并存的考验，分析了入世对其产业，主要工业部门，服务业和高技术产业投资环境的影响，并提出了相应的应对措施，包括从观念上要澄清几个问题，制定战略性外贸对策，加快产业结构优化与资产重组，以及各产业内部的针对性调整，如继续巩固农业的基础地位，加强制造业技术革新，扶持高技术产业和不放弃关键性服务行业等。     

基于CMIP6集合优化数据集的全球陆地极端气候变化预估

预估极端气候事件趋势能够降低其引起的灾害风险.该文基于CMIP6集合优化数据集EPTGODD-WHU,选取5个极端气候指数,即最高气温极大值(TXx)、最高气温极小值(TXn)、最低气温极大值(TNx)、最低气温极小值(TNn)和最大月降水量(PXx),并结合GIS分析手段,对2021—2100年SSP1-2.6、SSP2-4.5和SSP5-8.5情景下的全球陆地极端气温及降水进行预估.结果表明：1)相较于CMIP单一模式,EPTGODD-WHU数据集模拟性能显著提升,气温及降水的空间相关系数分别达到0.99和0.81.2) SSP5-8.5情景下,年最低气温和最高气温均上升明显,且这种上升趋势年内波动不大,地球陆地极寒地区将面临升温的风险,而赤道等极热地区将处于年内长时间酷热状态.3)六大洲在SSP5-8.5情景下的极端降水整体上升趋势最剧烈,但北美洲密西西比平原和滨海平原的地区在SSP5-8.5情景下在未来面临较高的旱灾风险.4)中国西南部地区的极端降水在三个情景下均呈稳定的增幅,且增幅高达60%,预示面临较高的洪灾风险.     

全球变暖背景下极端降水变化率与气温的响应关系

以中国整体为研究区,基于1960—2013年520个气象站逐日降水和气温数据,选取极端降水变化率(α)和饱和水汽压变化率(β)2个指标,定量分析了极端降水与全球变暖之间的内在联系.结果表明:全球变暖背景下我国整体上极端降水呈现增加的趋势,α和β分别为6.4%·℃-1和9.3%·℃-1,且α更接近理论值(约7%·℃-1),β与平均气温存在指数定量化关系.在此基础上,根据平均气温的不同将我国划分为9个对照组,进一步分析其空间差异,结果表明:α和β在空间上存在显著的正相关关系(r=0.63),具体表现为平均气温较高的地区,α和β值也较大.证明了饱和水汽压随温度的变化率可以从大尺度上解释极端降水增加的空间变化特征.     

Extraseasonal ensemble numerical predictions of winter climate over China

Using the nine-level Atmospheric General Circulation Model developed at the Institute of Atmospheric Physics (IAP9L-AGCM) under the Chinese Academy of Sciences, 30-year extraseasonal short-term ensemble hincast of winter climate is performed, with integrations starting from annual autumn during 1969—1998. Winter climate predictability over China is then evaluated for the first time. It follows that the predictability is higher in tropics than in extratropics. Also, it is higher over ocean compared with land, especially for surface air temperature. With height increasing in troposphere, the predictability of geopotential height slightly changes zonally, but for weakening of band-ship distribution and dropping near the date line. Of all analyzed variables, the prediction skill of air temperature and geopotential height (precipitation) is the highest (smallest). In addition, the predictability of winter climate over China and even East Asia enhances obviously during ENSO cycle, especially during La Nia phase. Simulation comparison against verifying analysis for surface temperature anomaly exhibits the model抯 skill in predicting surface temperature抯 interannual variation trend in winter.     

Wintertime extreme precipitation event over southern Chinaand its typical circulation features

This study objectively defined an extremeprecipitation event （EPE） over southern China and inves-tigated the associated typical circulation pattern on theintraseasonal time scale. The occurrence of the EPEresulted from the joint operations of anomalous circula-tions over the subtropics and mid-high latitudes. During theEPE, simultaneous enhancements of the trough over theBay of Bengal （BBT） and the Western Pacific subtropicalhigh （WPSH） facilitated thetions over southern China,abundant water vapor condi-whereas the weakened EastAsian major trough （EAT） led to a moderate cold airinvasion to that region, producing a persistent convergencezone over southern China. Wave train pattern in NorthAtlantic and Europe may be viewed as precursory signalsfor the EPE over southern China, and it contributed to theRossby wave propagation in association with the EPE.These wave packets propagated toward East Asia mainlyalong the North African-Asian subtropical westerly jetwaveguide. Low-frequency disturbances along this wave-guide contributed to the enhancement of the BBT andWPSH and the weakening of the EAT, constitutingfavorable circulation conditions for the EPE.     

1961-2013年东北区域极端气温的变化特征

为研究东北地区极端气温变化规律,利用1961-2013年最高、最低气温资料,采用线性趋势分析方法,从时间变化、空间分布、发展趋势、指数强度方面对极端气温指数绝对及相对变化的影响等角度分析了我国东北区域极端气温事件的变化规律。结果表明：东北区域冷指数减小,暖指数增大,指数强度越大,其绝对变化越小而相对变化越大;高强度极端气温对温度变化的贡献大于低强度极端气温;高强度极端气温指数变化率增加幅度大于低强度指数,冬季各指数变化率最大;结冰日数、冷昼日数和暖昼日数变化率在东北区域的南北两侧较大;研究时段内,夏季日数、炎热夜数、暖昼日数和暖夜日数增加的幅度不断增大;霜冻日数、结冰日数、冷昼日数和冷夜日数减少的变化率先增大后减小。     

中国地区工业硫酸盐气溶胶对辐射和温度的影响

 将大气化学模式和区域气候模式连接,以中国地区1994年1,4,7,10月为研究对象,模拟了气候变化,并分析了由于大气化学过程形成的硫酸盐气溶胶的对地气系统辐射收支、温度、降水量等气候因子的影响.通过分析发现:硫酸盐气溶胶在晴空大气顶和云天大气顶处产生负的辐射强迫,将使地表温度下降,使降水量减少.     

1980-2010年华北地区极端高温天气气候事件特征分析

基于1980-2010年共31年NCEP再分析资料和华北地区地面台站资料,采用百分位阈值法研究了华北地区夏季极端高温天气事件的时空特征,并对其环流成因进行了分析.结果表明,1980-2010年华北地区极端高温日数和极端高温事件发生时的日平均、最高温度都有明显的增加趋势,其中极端高温日数的增加趋势尤为显著,线性趋势系数达到0.261,通过了0.01的显著性水平检验.空间分布上,近10年华北地区的极端高温日数显著增加,并且北部地区增加大于南部,极端高温多发区由20世纪80年代的"南多北少"向目前的"北多南少"分布态势转变;合成分析的结果表明,在华北地区极端高温日数偏多年,副高势力较强,且西伸脊点偏西,中高纬度地区为两高一低型,造成华北地区极端高温日数偏多的大气环流系统是其中偏东的深厚大陆高压,此系统强度大且在对流层低层势力尤为强盛,位势高度异常在850 h Pa上超过5 gpm.     

Arctic Oscillation influence on daily temperature variance in winter over China

The relationship between the Arctic Oscillation (AO) and daily temperature variance of 150 Chinese stations are investigated in the present study for wintertime (1 November through 31 March) in the period of 1954--2001. Resuits show that the temperature variance significantly decreases during the high AO years,and increases in low AO cases. A key factor connecting them is the Siberian High,particularly the high-frequency fluctuations of the High.Within the seasonal time scale, the frequency of low-temperature extremes (daily temperature anomaly below-2σ,σ is the standard deviation of daily temperature for a given winter and a given station) displays an odd relation to the variance: a larger (smaller) variance is found to be associated with smaller (greater) frequency of low-temperature events. That is due to the non-normal distribution of the temperatures, and also influenced by the phases of AO. During the last 50 years or so, AO experiences a significant increasing trend, meanwhile the variance of daily sea level pressure (SLP) in the central region of Siberian High has decreased at a rate of-10.7%/10 a. These result in a significant weakening of the daily temperature variance in China with a trend of -4.1%/10 a, and a significant increase in the intra-seasonal low-temperature extremes at a rate of 0.16d/10 a.     

The climate influence of anthropogenic land-use changes on near-surface wind energy potential in China

There is considerable interest in the potential impact of climate change on wind energy in China. The climate change of near-surface wind energy potential in China under the background of global warming and its association with anthropogenic land-use changes are investigated by calculating the difference in surface wind speeds between the NCEP/NCAR reanalysis data and the observations since the reanalysis dataset contains the influence of large-scale climate changes due to greenhouse gases, it is less sensitive to regional surface processes associated with land types. The surface wind data in this study consist of long-term observations from 604 Chinese Roution Meteorological Stations and the NCEP/NCAR reanalysis data from 1960-1999. The results suggest that the observed mean wind speeds significantly weakened and the near-surface wind power trended downward due to urbanization and other land-use changes in the last 40 years. The mean wind energy weakened by -3.84 W·m^-2 per decade due to the influence of anthropogenic land-use change, which is close to the observed climate change （-4.51 W·m^-2/10 a）.     

No upward trends in the occurrence of extreme floods in central Europe

Extreme river floods have been a substantial natural hazard in Europe over the past centuries, and radiative effects of recent anthropogenic changes in atmospheric composition are expected to cause climate changes, especially enhancement of the hydrological cycle, leading to an increased flood risk. For the past few decades, however, observations from Europe do not show a clear increase in flood occurrence rate. Here we present longer-term records of winter and summer floods in two of the largest rivers in central Europe, the Elbe and Oder rivers. For the past 80 to 150 yr, we find a decrease in winter flood occurrence in both rivers, while summer floods show no trend, consistent with trends in extreme precipitation occurrence. The reduction in winter flood occurrence can partly be attributed to fewer events of strong freezing-following such events, breaking river ice at the end of the winter may function as a water barrier and enhance floods severely. Additionally, we detect significant long-term changes in flood occurrence rates in the sixteenth to nineteenth centuries, and conclude that reductions in river length, construction of reservoirs and deforestation have had minor effects on flood frequency.     

Analyses on the climate change responses over China under SRES B2 scenario using PRECIS

The global climate has been altered by the anthro- pogenic forcing due to greenhouse gases (GHGs) emis- sions. It is pointed out in the Third Assessments Report (TAR)[1] of Intergovernmental Panel on Climate Change (IPCC) in 2001 that over the 20th centur…     

1761—1780年极端气候事件影响下的天山北麓移民活动研究

以1761—1780年新疆天山北麓的移民活动为研究对象,讨论移民政策、移民高潮与移民迁出地极端气候事件之间的关系。结果显示:1761—1780年间有3次移民高潮,分别发生在1764—1766年、1772—1773年和1777—1780年。1761—1780年,天山北麓的移民政策没有发生大的改变,但1763—1765年、1771年、1775—1778年移民迁出地——河西走廊发生了3次极端干旱事件,揭示1761—1780年的3次移民高潮受极端干旱事件的驱动,且移民高潮的出现滞后迁出地极端干旱事件1~2年。第3次干旱推动了第3次移民高潮的出现,使得当时的清政府于1780年转变了移民政策。1775—1780年河西走廊极端干旱事件—天山北麓移民高潮—政府移民政策转变之间形成了一个完成的气候变化-社会响应链条。     

近50年来中国西北地区尘暴发生及其可能的动力机制

结合美国国家环境预报中心及国家大气研究中心再分析气候资料,通过考察1960-2007年中国西北地区137个站点春季累计尘暴发生频次与研究区和西伯利亚地区的温度、气压、风速等气候因子之间的相关关系,初步揭示了西北地区春季尘暴发生的演化趋势及其潜在动力机制.研究表明,1960-2007年中国西北地区尘暴频次总体呈减少趋势;西伯利亚和西北地区上一年冬季和当年春季均温与尘暴频次均呈显著负相关;西伯利亚和西北地区冬春季温差、气压差与尘暴频次均呈正相关.初步研究表明,近20年来,西伯利亚和西北地区温度的升高以及西伯利亚地区较高的增温幅度导致尘暴发生区平均风速的减小,是尘暴频次减少的主要动力原因.