The earth system: regional–global linkages

Understanding the earth system requires that the two-way linkages between regions and the global system be well understood and predictable. Most studies of global change are undertaken thematically across limited disciplinary boundaries; few are attempted holistically across many disciplines within regions. The regional approach offers many advantages. Here a variety of linkages associated with the regions of Southern Africa, South Asia, East Asia and Southeast Asia are presented to illustrate the power of a regional approach to earth system science. Major findings include the extent to which long-range transport of aerosols and nutrients affect terrestrial and marine ecosystem functioning in and around southern Africa. Aerosol transport, and the development of a regional haze layer, over South Asia are shown to alter significantly the radiative forcing of change in the atmosphere over the region. Changes in land cover and use over East Asia over along period of time are shown to have affected the strength of the monsoon circulation significantly. Finally, rampant economic development and globalization in Southeast Asia are demonstrated to have been a significant driver of regional change. Electronic Publication     

三峡库区局地气候变化

三峡库区地处鄂西和渝东的崇山峻岭中，局地气候受山谷和水体的共同影响，冬暖夏热，降水丰富。利用三峡库区及其周边地区33个气象观测站1961~2006年降水与温度观测资料，对2003年蓄水前后的降水、气温等要素作了时间对比分析，同时分别选取近库区和远库区站点作降水比值和温度差值分析，结果表明近几年库区降水较常年偏少，但降水趋势与西南地区降水年代际变化一致。20世纪90年代之后三峡库区气温有显著上升趋势，蓄水后受水域扩大影响近库地区的气温发生了一定变化，表现出冬季增温效应，夏季有弱降温效应，但总体以增温为主。由于三峡工程局地气候影响是一个复杂、长期的气候调节过程，所给出的结果只是三峡水库蓄水至今3年时间的观测分析结果，同时蓄水前后温度变化还需要更长时间观测分析统计，对水库水域扩大影响造成的局地气候效应有待更多研究方法及模式结果的验证。     

Potential responses of terrestrial biodiversity in Southern Africa to anthropogenic climate change

Key studies supported by species-level data collection have provided early indications of the potential implications of unmitigated change for the ecosystems and biodiversity of southern Africa. These suggest a significant threat to biodiversity, both from changing bioclimatic suitability and changing atmospheric CO₂ level that seems to affect the competitive balance between woody and herbaceous plants in the dominant savanna biome of this region. Modeling efforts suggest significant implications of unmitigated climate change for this region, but assumptions underpinning methods such as bioclimatic modeling must be recognized, some of which might lead to over estimates of the rate and extent of the potential impacts. General trends and level of coincidence between various types of studies do support a high degree of concern for a substantial portion of southern African biodiversity under unmitigated climate-change scenarios. The most significant changes in ecosystem structure (both increases and decreases in woody plant cover), and associated faunal diversity changes, are projected in the dominant savanna vegetation type in this region, while the most significant biodiversity loss is projected for the winter rainfall region. Follow-up work to detect early signs of climate change identify regions of high- and low-potential impacts, and experimental work to test some important hypotheses relating to the future evolution of climate-change impacts across the region are very few and urgently required.     

1959～2008年湖北省暴雨的气候变化特征

利用湖北省17个气象站1959~2008年逐日降水资料，采用克里格插值法、线性趋势、累计距平、滑动平均及Mann Kendall、复Morlet小波函数等方法分析湖北省暴雨的空间分布规律和时间演变特征。结果表明：湖北省存在以鄂东南和鄂东北为两个暴雨高值高频中心、鄂西北为低值低频中心的多中心分布特征，整体呈现出从东南向西北递减的地域分布，且大暴雨高频区、特大暴雨多发区和暴雨极大值区均出现在鄂东地区。时间演变趋势上，近50年来湖北省暴雨日数呈弱的增长趋势，暴雨量经历了偏少 偏少 偏多 偏多 偏少的年代际变化过程，异常暴雨年中暴雨日数偏多年较偏少年出现的频率高，全省暴雨日数和暴雨量在1978年发生突变，且存在9 a和5 a的周期振荡，而各分区暴雨日数均表现出显著地8~10 a的年代际周期特征     

Simulation of Indian summer monsoon rainfall and its intraseasonal variability in the NCAR climate system model

The broad climatological features associated with the Asian monsoon circulation, including its mean state and intraseasonal and interannual variability over the Indian subcontinent as simulated in the National Center for Atmospheric Research (NCAR) global coupled climate system model (CSM) in its control reference experiment, are presented in this paper. The CSM reproduces the seasonal cycle as well as basic observed patterns of key climatic parameters reasonably well in spite of some limitations in simulation of the monsoon rainfall. However, while the seasonality in rainfall over the region is simulated well, the simulated area-averaged monsoon rainfall is underestimated to only about 60% of the observed rainfall. The centers of maxima in simulated monsoon rainfall are slightly displaced southward as compared to the climatological patterns. The cross-equatorial flow in simulated surface wind patterns during summer is also stronger than observed with an easterly bias. The transient experiment with a 1% per year compound increase in CO₂ with CSM suggests an annual mean area-averaged surface warming of about 1.73 °C over the region at the time of CO₂ doubling. This warming is more pronounced in winter than during the monsoon season. A net increase in area-averaged monsoon rainfall of about 1.4 mm day^–1, largely due to increased moisture convergence and associated convective activity over the land, is obtained. The enhanced intraseasonal variability in the monsoon rainfall in a warmer atmosphere is confined to the early part of the monsoon season which suggests the possibility of the date of onset of summer monsoon over India becoming more variable in future. The enhanced interannual and intraseasonal variability in the summer monsoon activity over India could also contribute to more intense rainfall spells over the land regions of the Indian subcontinent, thus increasing the probability of extreme rainfall events in a warmer atmosphere. Electronic Publication     

Vertical distribution and inventories of 137Cs in the Syrian soils of the eastern Mediterranean region

Vertical distribution and inventories of (137)Cs have been determined using radiocesium distributions in presumably undistributed soil profiles, collected from 36 sites distributed all over Syria (eastern Mediterranean region). Vertical distributions of (137)Cs in the collected profiles were found to be strongly correlated with soil type and five groups were identified. Based on these profiles, total (137)Cs inventory (bomb test and Chernobyl) varied between 320 Bq m(-2) and 9,647 Bq m(-2). Geographical mapping of (137)Cs inventories showed that the highest values were found in the coastal, middle and north-east regions of Syria indicating that Chernobyl atmospheric contribution to the total (137)Cs deposition in the region is predominant. In contrast, the lowest values were found in the south-east region (Syrian Badia), where a relatively uniform distribution was observed, which may only be attributed to the past global nuclear bomb test. The measured inventories were also compared with a mathematical model for estimating bomb derived (137)Cs reference inventories.     

The geographic distribution of radionuclide deposition across the continental US from atmospheric nuclear testing

For the first time, calculations for the more than 3000 counties of the US have been completed that estimate the average deposition density (Bq m(-2)) of more than 40 radionuclides in fallout from atmospheric nuclear weapons tests conducted in the US (1951-1962) and 19 radionuclides from tests conducted elsewhere in the world (1952-1963). The geographic pattern of deposition across the US, as well as the amount of fallout deposited, varied significantly depending on whether the tests were conducted within or outside of the US. Fallout deposited from the Nevada Test Site (NTS) varied geographically as a result of dispersion and dilution in the atmosphere, the wind patterns following each test, and the occurrence of localized rainfall events. In general, states immediately east of the NTS received the highest deposition from tests conducted there. In contrast, the variation in deposition across the country from global fallout was less than for NTS fallout primarily reflecting variations in annual precipitation across larger regions. Hence, in the eastern and mid-western US, where rainfall is above the national average, higher levels of global fallout were deposited than in the more arid southwestern states. This paper presents a summary of the methods used and findings of our studies on fallout from NTS and global fallout, with emphasis on two of the most important radionuclides, (131)I and (137)Cs.     

1960~2014年秦岭南北无霜期时空变化特征及对比分析

全球气候变暖背景下，自然生态环境敏感区农业热量资源的时空特征研究具有重要的现实意义。依据1960~2014年秦岭南北47个气象站数据，利用线性趋势、M-K检验和kriging插值法对无霜期时空变化进行分析。结果显示：从时间上看，秦岭南北无霜期随纬度增加而减少，初霜日和无霜期在年际波动中略有下降后快速上升，终霜日在波动中略有上升后快速下降。55年来无霜期呈显著的延长趋势且发生增多突变，秦岭以北、秦岭南坡、汉水流域和巴巫谷地的延长速率分别为0.400 6、0.280 4、0.396 1和0.407 5 d/a，突变年份分别为1999、2002、2001和1990年。从空间上看，无霜期平均值和标准差由南向北增加，80%站点初霜日推后、终霜日提前和无霜期延长。多数无霜期延长是初霜日推后与终霜日提前的共同影响。无霜期在28个站点呈波动变化，19个站点发生突变，突变时间多在1990s~2000s，2000s的突变区域面积最大且集中分布在东北部。分析结果可为气候变化对生态环境和农业生产布局的影响提供参考。     

Options for water storage and rainwater harvesting to improve health and resilience against climate change in Africa

West and East Africa experience high variability of rainfall that is expected to increase with climate change. This results in fluctuations in water availability for food production and other socioeconomic activities. Water harvesting and storage can mitigate the adverse effects of rainfall variability. But past studies have shown that when investments in water storage are not guided by environmental health considerations, the increased availability of open water surface may increase the transmission of water-related diseases. This is demonstrated for schistosomiasis associated with small reservoirs in Burkina Faso, and for malaria in Ethiopia around large dams, small dams, and water harvesting ponds. The concern is that the rush to develop water harvesting and storage for climate change adaptation may increase the risk for already vulnerable people, in some cases more than canceling out the benefits of greater water availability. Taking health issues into account in a participatory approach to planning, design, and management of rainwater harvesting and water storage, as well as considering the full range of water storage options would enable better opportunities for enhancing resilience against climate change in vulnerable populations in sub-Saharan Africa.     

21世纪前期湖南可持续发展的工业化对策研究

湖南是我国中部农业精华地带的组成部分，长期以来，由于受资源禀赋、地理区位、国家政策导向和原有基础等多重影响，形成了传统农业发达而工业发展相对滞后的区域经济。21世纪前期，为实现经济总量的快速增长和区域经济质量的提升，追赶上东部经济发达地区，湖南提出了工业化带动的区域经济战略。由于现阶段国内外经济环境已经发生了较大的变化，加之在科技发展、资源结构和区域经济实力等方面存在与东部沿海发达地区较大的差异，湖南的工业化必须在对原有传统工业化战略有所扬弃的基础上，形成具有自身特色的可持续发展的工业化战略。战略的基本点表现为：(1)将优势传统农业产业进行工业化改造，实现高新技术与传统产业的结合；(2)打破城乡户籍隔离体制，依托城镇化的率先突破，带动工业化发展；(3)高度警觉工业化可能产生的负效应，分类推进，实现不同地区可持续发展的工业化战略。     

中国南方地区近60 a来降雨量与降雨侵蚀力时空变化研究

基于南方地区9个省份41个气象站点1956~2015年共60 a逐日降雨量资料,采用线性回归、Kriging插值等方法分析了南方地区降雨量和降雨侵蚀力的时空变化特征。结果表明:南方地区降雨以侵蚀性降雨为主,且比较集中,区域强降雨事件出现的频次在增加。南方地区年均降雨侵蚀力变化范围在3 477.30~24 878.65 MJ·mm/(hm~2·h·a)之间,平均值为9 919.93 MJ·mm/(hm~2·h·a),总体由南往北逐渐减少的分布规律。在季节分布上降雨侵蚀力主要集中在夏季。60 a来南方大部分地区年降雨侵蚀力均呈上升趋势,其中海南、浙江、江西3省上升趋势较为明显,说明这些地区面临较大的土壤侵蚀潜在压力。     

长江中下游冬小麦春季湿渍害灾损风险评估

春季湿渍害对南方冬小麦生长发育和产量形成影响很大。选取能较好反映冬小麦湿渍害特征的降雨量、日照和作物需水量构建湿渍害气象判别指数,从春季湿渍害产量实际损失的角度,对受灾频率、因灾减产频率、产量损失风险强度进行分析,基于减产频率和产量灾损风险强度建立风险评估模型,并依据风险值大小进行分区。结果表明:沿江江南地区冬小麦春季湿渍害受灾频率最高,为风险高值区,约占全区台站27%;风险中值区范围较大,约占47%,分布在江淮东部、淮北大部、江汉平原以及鄂东南地区;低风险区约占全区16%,主要分布在湖北北部和淮北局部地区。     

长江中下游地区连阴雨变化特征分析

利用长江中下游地区86站1961~2011年逐日降水量资料,采用线性倾向估计法和M-K突变检验法,分析该地区年连阴雨日数、过程次数、总降水量及降水强度的时空变化特征。结果显示:长江中下游地区大部连阴雨日数有70~130 d/a、连阴雨过程次数有7~12次/a、连阴雨总雨量为500~1 300 mm/a、年均连阴雨强度为8~10 mm/d,连阴雨过程持续时间多在8~11 d/次左右。其中连阴雨日数和频次总体呈现出南多北少、连阴雨总雨量呈东南多西北少、雨强呈东强西弱的分布态势;近50 a来,长江中下游地区平均年连阴雨日数、连阴雨过程频次、连阴雨总雨量均呈减少趋势,减少速率分别为3.8 d/10 a、0.3次/10 a、18.5 mm/10 a,其中连阴雨日数、频次减少趋势显著;降水强度呈显著增加趋势,增加速率为0.2 mm/(d·10 a)。空间上,西部连阴雨日数、过程次数均呈显著减少趋势,东部呈微弱的减少趋势;大部地区连阴雨总量均呈显著减少趋势,其中西部尤为突出。突变分析发现,长江中下游连阴雨存在突变年份,各统计因子突变主要集中在1991~2011年,连阴雨日数减少突变发生在2003年,2006年起减少趋势超过显著性水平;连阴雨频次突变发生在2004年,2010年起减少趋势超过显著性水平;连阴雨总雨量突变发生在2006年,但这种突变不显著;连阴雨降水强度于1992~1994年发生突变,2010年起增加趋势超过显著性水平。     

洪泽湖流域洪涝灾害演变趋势及其与El Ni(n)o事件关系

为分析洪泽湖流域洪涝灾害在千年尺度序列上的演变趋势,采用统计历史洪涝记录的方法,分析了气候变化背景下洪涝灾害的响应过程,探讨了洪泽湖流域洪涝灾害同El Ni(n)o事件的关系.结果表明:近1 000 a来洪泽湖流域洪涝灾害的频度总体是趋于上升的,这种变化趋势同气候变化的趋势是一致的.研究结果显示:公元1000～1400年洪涝记录偏少,同我国东部地区尤其是中世纪暖期出现的一次200 a以上的干旱化过程有较好的对应性.1400～1800年是洪泽湖流域洪涝的多发期,这一事实同我国东部1550～1850年小冰期期间总体偏湿的环境特征相一致.分析洪涝灾害变化同El Ni(n)o事件对应性关系表明:在El Ni(n)o事件年及其次年是洪泽湖流域洪涝的多发年份.这可能是由于El Ni(n)o事件通过改变西太平洋副高的强度与位置,以及大气环流形势而引起的降水异常所致.了解洪泽湖流域洪涝的演变趋势及其同El Ni(n)o的关系对于长期防灾减灾策略具有重要的参考意义.     

洪泽湖流域洪涝灾害演变趋势及其与El Nio事件关系

为分析洪泽湖流域洪涝灾害在千年尺度序列上的演变趋势，采用统计历史洪涝记录的方法，分析了气候变化背景下洪涝灾害的响应过程，探讨了洪泽湖流域洪涝灾害同El Nio事件的关系。结果表明：近1 000 a来洪泽湖流域洪涝灾害的频度总体是趋于上升的，这种变化趋势同气候变化的趋势是一致的。研究结果显示：公元1000~1400年洪涝记录偏少，同我国东部地区尤其是中世纪暖期出现的一次200 a以上的干旱化过程有较好的对应性。1400~1800年是洪泽湖流域洪涝的多发期，这一事实同我国东部1550~1850年小冰期期间总体偏湿的环境特征相一致。分析洪涝灾害变化同El Nio事件对应性关系表明：在El Nio事件年及其次年是洪泽湖流域洪涝的多发年份。这可能是由于El Nio事件通过改变西太平洋副高的强度与位置，以及大气环流形势而引起的降水异常所致。了解洪泽湖流域洪涝的演变趋势及其同El Nio的关系对于长期防灾减灾策略具有重要的参考意义。     

Has recent climate warming affected the dates of bird arrival to the Il℉men Reserve in the Southern Urals?

The results of regression and correlation analyses of long-term data (1971–2005) on the dates of arrival of 16 bird species to the Il’men State Nature Reserve (the Southern Urals) show that they have not changed in most of these birds, unlike in many countries of Europe and North America. This is explained primarily by the absence of any significant trends in the dynamics of spring air temperatures in the study region. Only the herring gull Larus argentatus and the lapwing Vanellus vanellus have shown a significant tendency to arrive earlier, while the garganey Anas querquedula has shown a tendency to arrive on later dates in the past two decades. Nevertheless, interannual fluctuations in the dates of arrival are well manifested in both early arriving species wintering in Europe and late-arriving species wintering in Africa. These fluctuations largely depend on temperature conditions in spring. As a rule, almost all species studied—from waterbirds to passerines—appear in the Il’men Reserve earlier in years with early and warm springs than in cold years. Hence, spring weather is the key factor determining the dates of arrival of migratory birds to the study region.     

Spatiotemporal variation in rainfall erosivity on the Chinese Loess Plateau during the period 1956–2008

Water resources and soil erosion are the most important environmental concerns on the Chinese Loess Plateau, where soil erosion and sediment yield are closely related to rainfall erosivity. Daily rainfall data from 60 meteorological stations were used to investigate the spatiotemporal variations in annual rainfall, annual erosive rainfall and annual rainfall erosivity on the Chinese Loess Plateau during the period 1956–2008. The annual rainfall, erosive rainfall and rainfall erosivity decreased over the past five decades, as determined by the Mann–Kendall test. A comparison of the annual averaged rainfall, erosive rainfall and rainfall erosivity from 1980 to 2008 with that from 1956 to 1979 revealed a remarkable spatial difference in the rainfall trends on the Loess Plateau. Regions of the plateau with major decreases in rainfall were primarily in the Hekouzhen-Longmen section of the middle Yellow River, especially in the Wuding River basin, the Fenhe basin and the northern-central Shanxi province, where the annual rainfall and erosive rainfall decreased by more than 10% and the annual rainfall erosivity decreased by more than 15%. The rainfall erosivity also decreased more than the annual rainfall. Because the annual rainfall has decreased significantly on the Chinese Loess Plateau over the past 50 years, it is important to better understand the ecological and hydrological processes affected by this climate change.     

上海霾气候数据序列重建及其时空特征

利用上海11个气象站点1960～2008年日均相对湿度、能见度以及天气现象资料，重建了上海近50 a霾气候数据序列，并从时间和空间两个方面分析了上海霾日数的气候特征和变化规律。结果表明，上海霾气候数据序列重建值与报表记录值之间变化形态存在着较好的一致性，重建值较记录值偏高。1960～2008年，上海霾日数以97 d/10 a的线性趋势显著增加，2002年以后霾日数总体上呈减少趋势。上海多年平均霾日数以冬季最多而夏季最少。近50 a，上海霾日数呈现出西南部最多 市区较多 东北和东南部最少的空间分布，霾日数的空间变化趋势则表现为西南部增加较多而东部增加较少。1981～2008年，上海霾日数在西部和南部都增加，东部则减少。〖     

青藏高原年日照时数的年代际变化趋势

利用1961~2007年青藏高原68个气象台站日照时数观测资料，通过统计方法分析了近47 a来青藏高原年日照时数的年代际变化趋势，得到以下几点初步认识：青藏高原年日照时数整体上呈现自东南向西北增加的特点，并且其空间变化趋势也存在明显的区域差异。青藏高原东南部、西藏中部和西藏西南部以及青海北部地区年日照时数减少较为明显，高原西部、西藏中东部地区和青海南部年日照时数呈增加趋势；近47 a来青藏高原年日照时数具有明显的年代际变化特征，年日照时数增加区和减少区分别存在12.1和21.1 a左右的时间尺度；增加区在20世纪60年代至80年代年日照时数处于偏多阶段， 90年代至21世纪初日照时数呈明显的减少趋势；减少区则表现为20世纪60年代至70年代年日照时数有所增加， 90年代日照时数开始急剧减少，21世纪初达到最低值。各年代之间年日照时数变化特点同样具有明显的区域差异。     

The Holocene dynamics of vegetation and climatic conditions on the eastern slope of the Subpolar Urals

Changes in the vegetation and climatic conditions on the eastern slope of the Subpolar Urals over the past 10000 years have been reconstructed on the basis of integrated palynological, botanical, and radiocarbon analysis of material from two sections of peat deposits in the floodplains of the Lyapin and Man’ya rivers (the Severnaya Sos’va basin). The dynamics of regional vegetation have been traced: from the herb–shrub tundra in the late postglacial time to the spruce–larch forest–tundra and sparse larch–birch–spruce stands in the Early Holocene, to birch–pine–spruce forests with an admixture of fir in the Middle Holocene, and to northern taiga forests with dominance of Scots pine and Siberian stone pine (similar to present-day forests) in the Late Holocene. The results show that the northern taiga zone of the study region in the period between approximately 5500 and 2500 years BP was occupied by forests of middle and southern taiga facies, as the climate was significantly warmer than it is today.