全国大部气温偏高北方风沙多干旱重——2002年3月——

3月份 ,全国大部地区气温普遍偏高 ;降水量空间分布不均 ,东北、华北、黄淮部分地区旱情持续或发展 ;北方地区出现大范围沙尘天气 ;南方多局地强对流天气 ;月日照时数大部地区接近常年。1　全国大部地区气温明显偏高3月份全国大部地区气温普遍偏高 ,尤其是东北和华北大部地区气温偏高异常显著。月平均气温除西南大部及青海、北疆中部等地接近常年或略偏低外 ,全国其余大部地区气温普遍偏高 2℃以上 ,其中东北三省大部、内蒙古东部、河北、京津、河南中北部、江苏东南部和浙江北部等地偏高 4～ 6℃。继 1、2月后 ,3月份全国平均气温再次达到1…     

寒潮爆发东北遭遇暴风雪 北方雨雪多西南持续干旱——2007年3月——

2007年3月，全国大部地区月平均气温比常年同期偏高；全国平均气温为4．5℃，比常年同期偏高1．3℃；月内气温起伏变化大，上中旬全国大部地区气温接近常年同期或偏低；下旬，全国大部地区气温异常偏高。全国平均降水量为31．5mm，较常年同期略偏多；北方大部地区较常年同期明显偏多，南方大部接近常年同期或偏少。月内，东北遭遇罕见暴风雪灾害；西南部分地区发生春旱；我国北方地区出现了5次沙尘天气过程；上旬，强冷空气影响我国大部地区，安徽、江苏等地局部遭受低温冷冻害；贵州、山东、江苏等地出现雷雨大风和冰雹等局地强对流天气；     

寒潮爆发东北遭遇暴风雪北方雨雪多西南持续干旱——2007年3月——

2007年3月,全国大部地区月平均气温比常年同期偏高;全国平均气温为4.5℃,比常年同期偏高1.3℃;月内气温起伏变化大,上中旬全国大部地区气温接近常年同期或偏低;下旬,全国大部地区气温异常偏高。全国平均降水量为31.5mm,较常年同期略偏多;北方大部地区较常年同期明显偏多,南方大部接近常年同期或偏少。月内,东北遭遇罕见暴风雪灾害;西南部分地区发生春旱;我国北方地区出现了5次沙尘天气过程;上旬,强冷空气影响我国大部地区,安徽、江苏等地局部遭受低温冷冻害;贵州、山东、江苏等地出现雷雨大风和冰雹等局地强对流天气;我国中东部地区大雾天气…     

强冷空气袭击全国南方出现少见低温——1999年12月——

12月份 ,全国大部地区雨雪稀少 ,气温接近常年或偏高 ,但气温起伏变化较大 ,南方因受强冷空气袭击发生较大范围冻害。由于南支系统不活跃 ,本月没有热带风暴生成。1　天气概况1 2月份 ,全国大部地区降水稀少 ,月降水量 ,除华南大部、云南东南部、四川南部、重庆大部、新疆天山地区及黑龙江、辽宁两省部分地区有 1 0～ 5 0 mm外 ,其余地区不足1 0 mm,其中华北平原、江淮、西北地区大部及西藏大部、湖北东部、湖南中部等地基本无雨雪 ,与常年同期相比 (图 1 ) ,除华南西南部及内蒙古东北部和中部、新疆天山地区等地偏多 5成至 2倍外 ,全国其余…     

东北遭遇罕见暴风雪北方出现5次沙尘天气

3月，全国平均气温为4．5℃，比常年同期偏高1．3℃；月内气温起伏变化大。上中旬，全国大部地区气温接近常年同期或偏低；下旬，全国大部地区气温异常偏高。全国平均降水量为31．5mm，较常年同期略偏多；北方大部地区较常年同期偏多，南方大部接近常年同期或偏少。月内，东北遭遇罕见暴风雪灾害；西南部分地区发生春旱；我国北方地区出现了5次沙尘天气过程。上旬，强冷空气影响我国大部地区，安徽、江苏等地的局部地区遭受低温冷冻害；贵州、山东、江苏等地出现雷雨大风和冰雹等局地强对流天气；     

东北遭遇罕见暴风雪 北方出现5次沙尘天气——2007年3月——

3月,全国平均气温为4.5℃,比常年同期偏高1.3℃;月内气温起伏变化大。上中旬,全国大部地区气温接近常年同期或偏低;下旬,全国大部地区气温异常偏高。全国平均降水量为31.5mm,较常年同期略偏多;北方大部地区较常年同期偏多,南方大部接近常年同期或偏少。月内,东北遭遇罕见暴风雪灾害;西南部分地区发生春旱;我国北方地区出现了5次沙尘天气过程。上旬,强冷空气影响我国大部地区,安徽、江苏等地的局部地区遭受低温冷冻害;贵州、山东、江苏等地出现雷雨大风和冰雹等局地强对流天气;我国中东部地区大雾天气频繁,湖北、安徽、广西等地发生暴雨、洪…     

北方气温波动较大 长江中下游多阴雨

20 0 3年 4月 ,我国有 3次较强冷空气过程和多次弱冷空气活动 ,全国大部有 3次明显降温过程 ,北方地区气温起伏较大。南支槽活跃 ,降水频繁 ,并有强对流天气。江淮、江南、华南大部地区降水量为 1 0 0～ 2 0 0mm ,局部达 30 0mm。1　天气概况4月份 ,月平均气温新疆大部、甘肃北部、内蒙古西部气温较常年低 1～ 2℃ ,其中北疆部分地区较常年低 3℃ ;全国其余大部地区普遍接近或高于常年 ,其中东北大部、云贵高原中部、广东西南部偏高 2～ 3℃ (见图1 )。图 1　 2 0 0 3年 4月平均气温距平 /℃　　月内我国冷空气活动频繁 ,受其影响 ,全国有不…     

全国大部气温偏高、降水偏少 1992年4月

本月,影响我国的冷空气活动弱,全国大部地区气温偏高,降水偏少;北方多风干旱,南方强对流天气频繁;上旬华南大部阴雨寡照。 天气概况 本月,影响我国的冷空气活动偏弱,大部地区的月平均气温比常年同期偏高。其中,西北大部、华北南部、黄淮东部、江淮大部以及湖北、湖南、江西等地偏高2℃;东北大部、华北北部、西南大部以及华南西部和江南东部偏高1℃左右;华南东部地区的月平均气温接近常年(图1)。上旬,北方大部、江南大部一般偏高1—3℃,其中,东北南部、内蒙古大部偏高4℃。中旬,西     

全国气温持续偏高 北方大部雨雪稀少——2002年2月——

2月份,由于影响我国的冷空气势力较弱,全国大部地区气温仍显著偏高;大部地区降水明显偏少,华北等地降水持续稀少,部分地区有旱情. 1 天气概况 2月份月平均气温与常年同期相比,全国气温普遍偏高.除青藏高原大部及云南中部偏高1～2℃外,全国其余大部地区偏高2℃以上,其中华北西部、西北地区东北部、黄淮、江淮及大兴安岭、北疆北部偏高4～6℃,东北大部及内蒙古中部、河北南部等地偏高6～9℃(图1).     

冷空气频繁 雨雪量偏少

本月,我国除东北和华南西部地区降水量比常年偏多、气温偏低外,其余大部地区气温接近常年或稍偏高,雨雪量偏少。 概况 一月隆冬,我国常常是北风呼啸,寒流滚滚,大江南北冰封雪飘的季节。本月,冷空气的活动虽然频繁,但强冷空气过程较少。除东北大部和内蒙东部屡遭冷空气袭击,气温比常年同期偏低1—2℃,部分地区达3—4℃(见图1),出现了较为严寒的隆冬外,华南地区和新疆北部也偏低1—3℃。全国大部地区的月平均气温接近常年同期或略偏高。其中,西北大部分地区偏高1—2℃(见图1)。     

Climate policy strength compared: China,the US,the EU,India, Russia,and Japan

The few systematic international comparisons of climate policy strength made so far have serious weaknesses, particularly those that assign arbitrary weightings to different policy instrument types in order to calculate an aggregate score for policy strength. This article avoids these problems by ranking the six biggest emitters by far – China, the US, the EU, India, Russia, and Japan – on a set of six key policy instruments that are individually potent and together representative of climate policy as a whole: carbon taxes, emissions trading, feed-in tariffs, renewable energy quotas, fossil fuel power plant bans, and vehicle emissions standards. The results cast strong doubt on any idea that there is a clear hierarchy on climate policy with Europe at the top: the EU does lead on a number of policies but so does Japan. China, the US, and India each lead on one area. Russia is inactive on all fronts. At the same time climate policy everywhere remains weak compared to what it could be.

Policy relevance

This study enables climate policy strength, defined as the extent to which the statutory provisions of climate policies are likely to restrict GHG emissions if implemented as intended, to be assessed and compared more realistically across space and time. As such its availability for the six biggest emitters, which together account for over 70% of global CO₂ emissions, should facilitate international negotiations (1) by giving participants a better idea of where major emitters stand relative to each other as far as climate policy stringency is concerned, and (2) by identifying areas of weakness that need action.     

1,800 Years of abrupt climate change, severe fire, and accelerated erosion, Sierra Nevada, California, USA

This paper provides both a detailed history of environmental change in the Sierra Nevada over the past 1,800 years and evidence for climate teleconnections between the Sierra Nevada and Greenland during the late Holocene. A review of Greenland ice core data suggests that the magnitudes of abrupt changes in temperature and precipitation increased beginning c. 3,700 and 3,000 years ago, respectively. Precipitation increased abruptly 1,300 years ago. Comparing paleotemperature data from Cirque Peak, CA with paleoprecipitation data from Pyramid Lake, NV suggests that hot temperatures occurred at the beginnings of most severe droughts in the Sierra Nevada over the past 1,800 years. Severe fires and erosion also occurred at Coburn Lake, CA at the beginning of all severe droughts in the Sierra Nevada over the past 1,800 years. This suggests that abrupt climate change during the late Holocene caused vegetation and mountain slopes in some areas to be out of equilibrium with abruptly changed climates. Finally, the ending of drought conditions in Greenland coincided with the beginning of drought conditions in the Sierra Nevada over the past 1,800 years, perhaps as a result of the rapidly changed locations of the Earth??s major precipitation belts during abrupt climate change events.     

The temperature dependent,infrared absorption cross-sections for the chlorofluorocarbons: CFC-11, CFC-12, CFC-13, CFC-14, CFC-22, CFC-113, CFC-114, and CFC-115

The infrared absorption cross-sections for eight commonly used halogenated methanes and ethanes have been measured as a function of temperature from 203 to 293 K. High resolution spectra (0.03 cm^-1) have been used to derive integrated band strengths and peak cross-sections associated with the spectral features in the infrared region from 600 to 1500 cm^-2. The values obtained in this study are compared to those from previous reports, and recommendations are made for uses in atmospheric sensing and radiative energy transfer models. The observed temperature dependence in the spectral features is also discussed.     

Wind-driven, double-gyre, ocean circulation in a reduced-gravity, 2.5-layer, lattice boltzmann model

A coupled lattice Boltzmann （LB） model with second-order accuracy is applied to the reduced-gravity, shallow water, 2.5-layer model for wind-driven double-gyre ocean circulation. By introducing the secondorder integral approximation for the collision operator, the model becomes fully explicit. The Coriolis force and other external forces are included in the model with second-order accuracy, which is consistent with the discretization accuracy of the LB equation. The feature of the multiple equilibria solutions is found in the numerical experiments under different Reynolds numbers based on this LB scheme. With the Reynolds number increasing from 3000 to 4000, the solution of this model is destabilized from the anti-symmetric double-gyre solution to the subtropic gyre solution and then to the subpolar gyre solution. The transitions between these equilibria states are also found in some parameter ranges. The time-dependent variability of the circulation based on this LB simulation is also discussed for varying viscosity regimes. The flow of this model exhibits oscillations with different timescales varying from subannual to interannual. The corresponding statistical oscillation modes are obtained by spectral analysis. By analyzing the spatiotemporal structures of these modes, it is found that the subannual oscillation with a 9-month period originates from the barotropic Rossby basin mode, and the interarmual oscillations with periods ranging from 1.5 years to 4.6 years originate from the recirculation gyre modes, which include the barotropic and the baroclinic recirculation gyre modes.     

基于L波段探空的云区边界识别改进算法

利用气象业务中使用的L波段探空数据和毫米波云雷达观测资料,分析探空相对湿度在入云和出云时的变化规律,提出一种基于探空相对湿度阈值与梯度相结合的云区边界识别改进算法,并利用云雷达观测数据对算法识别结果进行验证.利用北京市南郊观象台2019年1—6月层状云样本验证分析,结果表明:改进算法相比相对湿度阈值法,对云区边界识别更...     

The microstructure of selected, small, isolated, cumulus clouds near Red Deer, Alberta

Physical experiments designed to explore the potential of rain augmentation through airborne glaciogenic seeding on small, isolated non-precipitating cumuliform clouds near Red Deer, Alberta were carried out during the period 1982–1985. The microstructure of 90 cumulus congestus clouds have been documented through repeated in-situ sampling using a cloud physics instrumented aircraft platform. Observations from the inspection passes of 57 clouds seeded with either dry ice pellets or silver iodide pyrotechnics, and all the passes of 33 natural clouds are presented.Measurements of the cloud droplet concentration indicate that Alberta cumulus clouds are typically continental in nature, with an average droplet concentration of 535 cm⁻³ and an average droplet diameter of 10.6 μm. Alberta clouds have average liquid water contents of 0.57 g m⁻³, with a peak 1-sec value of 3.17 g m⁻³. The 1-km average liquid water contents are 0.83 g m⁻³, with a peak value of 2.81 g m⁻³. Cloud lifetimes vary between 11 and 20 minutes. Concentrations of naturally occurring ice crystals are found to be low. The average maximum 1-km ice concentration was 31⁻¹, and the peak 1-km concentration was 73.11⁻¹ in the natural cloud dataset. Evidence of precipitation-sized particles was detected in 21% (7 of 33) of the clouds, and precipitation below cloud base was detected in 6% (2 of 33) of the clouds.A comparison of the Alberta cloud characteristics to the cumulus clouds from different locations showed that there are some distinct differences between Alberta clouds and the clouds from the other regions.     

江苏三次不同量级降雪过程的对比分析

利用常规观测资料和NCEP 1°×1°再分析资料,通过对发生在江苏的三次不同量级的区域性暴雪、大雪和中雪过程典型个例进行对比分析,发现降雪时,700hPa低空急流的位置和强度是影响降雪量级的主要因素之一;降雪区上空涡度的垂直分布遵循低层负涡度、中层正涡度和高层负涡度的配置,暴雪时正涡度强且正涡度区最为深厚,动力抬升作用强,中雪发生时正涡度区相对最为浅薄,不利于形成强辐合抬升,动力抬升作用弱。且暴雪和大雪发生时基本上整层都为垂直螺旋度正值区,中雪时没有出现明显的正值区;暴雪和大雪过程时中低层都具有明显的逆温层,中高层西南急流造成的对流层中层的爆发性增温是逆温层形成的关键,中雪发生时不一定有逆温层结;降雪强度与湿位涡分量绝对值存在一定的正相关关系。     

承德市一次由快速发展气旋诱发的大风天气分析

利用常规观测资料和NCEP/NCAR(1°×1°)逐6 h再分析资料,对承德市2017年5月5—6日大风天气的环流形势和物理量进行分析,结果表明气旋的快速发展(气旋加深率0.84 B)导致锋生加强,引发气压和变压梯度加大是导致大风的直接原因。500 hPa高压脊东移迫使冷空气向南堆积,高空槽不断发展成为冷涡,温度平流为地面气旋的发展提供热力条件,高低层涡度平流的差异,也是地面气旋快速发展的重要原因;当1.5 PVU位涡面伸展至对流层低层时,局地位涡异常在气旋的发展过程中不可忽视;高空急流出口区发生质量调整,出口区左侧的辐散强度达10×10~(-5) s~(-1),使低层大气减压,有利于气旋发展。     

Weeds, Insects, and Diseases

The geographic distribution, vigor, virulence, and agricultural impact of weeds, insects, and plant pathogens will be affected by climatic changes accompanying the global "greenhouse effect." Weed/crop competitive interactions, particularly among species differing in photosynthetic pathway (C₃ v C₄), may be altered, with the C₃ species favored by increasing CO₂. Physiological and biochemical changes induced in host crop plants by rising CO₂ may affect feeding patterns of pest insects. Compilation of climatic thresholds for phenological development of pest insects reveals the potential for shifts in pest behavior induced by global warming and other climatic change. Generation times may be reduced, enabling more rapid population increases to occur. Poleward migration may be accelerated during the crop season. The epidemiology of plant diseases also will be altered. Prediction of disease outbreaks will be more difficult in periods of rapidly changing climate and unstable weather. Environmental instability and increased incidence of extreme weather may reduce the effectiveness of pesticides on targeted pests or result in more injury to non-target organisms. Biological control may be affected either negatively or positively. Overall, the challenge to agriculture from pests probably will increase.     

Governance,complexity, and resilience

This special issue brings together prominent scholars to explore novel multilevel governance challenges posed by the behavior of dynamic and complex social-ecological systems. Here we expand and investigate the emerging notion of “resilience” as a perspective for understanding how societies can cope with, and develop from, disturbances and change. As the contributions to the special issue illustrate, resilience thinking in its current form contains substantial normative and conceptual difficulties for the analysis of social systems. However, a resilience approach to governance issues also shows a great deal of promise as it enables a more refined understanding of the dynamics of rapid, interlinked and multiscale change. This potential should not be underestimated as institutions and decision-makers try to deal with converging trends of global interconnectedness and increasing pressure on social-ecological systems.