The extreme dry/wet events in northern China during recent 100 years

Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.     

中国近代北方极端干湿事件的演变规律

Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.     

Climate variability and rural livelihoods: assessing the impact of seasonal climate forecasts in Lesotho

Climate variability acutely affects rural livelihoods and agricultural productivity, yet it is just one of many stresses that vulnerable rural households have to cope with. A livelihood approach is used to assess the potential role that seasonal climate forecasts might play in increasing adaptive capacity in response to climate variability, using Lesotho as a case study. An examination of the assets and strategies that rural households employ enables a holistic assessment of the impact seasonal forecasts could have on rural livelihoods. This research thereby bridges macro-level variability with local-level impacts and adaptation to provide insight into the dynamics of forecast use and impact among vulnerable groups.     

Interdecadal fluctuation of dry and wet climate boundaries in China in the past 50 years

Based on the mean yearly precipitation and the total yearly evaporation data of 295 meteorological stations in China in 1951-1999, the aridity index is calculated in this paper. According to the aridity index, the climatic regions in China are classified into three types, namely, arid region, semi-arid region and humid region. Dry and wet climate boundaries in China fluctuate markedly and differentiate greatly in each region in the past 50 years. The fluctuation amplitudes are 20-400 km in Northeast China, 40-400 km in North China, 30-350 km in the eastern part of Northwest China and 40-370 km in Southwest China. Before the 1980s (including 1980), the climate tended to be dry in Northeast China and North China, to be wet in the eastern part of Northwest China and very wet in Southwest China. Since the 1990s there have been dry signs in Southwest China, the eastern part of Northwest China and North China. The climate becomes wetter in Northeast China. Semi-arid region is the transitional zone between humid and arid regions, the monsoon edge belt in China, and the susceptible region of environmental evolution. At the end of the 1960s dry and wet climate in China witnessed abrupt changes, changing wetness into dryness. Dry and wet climate boundaries show the fluctuation characteristics of the whole shifts and the opposite fluctuations of eastward, westward, southward and northward directions. The fluctuations of climatic boundaries and the dry and wet variations of climate have distinctive interdecadal features.     

Interdecadal fluctuation of dry and wet climate boundaries in China in the past 50 years

Based on the mean yearly precipitation and the total yearly evaporation data of 295 meteorological stations in China in 1951–1999, the aridity index is calculated in this paper. According to the aridity index, the climatic regions in China are classified into three types, namely, arid region, semi-arid region and humid region. Dry and wet climate boundaries in China fluctuate markedly and differentiate greatly in each region in the past 50 years. The fluctuation amplitudes are 20–400 km in Northeast China, 40–400 km in North China, 30–350 km in the eastern part of Northwest China and 40–370 km in Southwest China. Before the 1980s (including 1980), the climate tended to be dry in Northeast China and North China, to be wet in the eastern part of Northwest China and very wet in Southwest China. Since the 1990s there have been dry signs in Southwest China, the eastern part of Northwest China and North China. The climate becomes wetter in Northeast China. Semi-arid region is the transitional zone between humid and arid regions, the monsoon edge belt in China, and the susceptible region of environmental evolution. At the end of the 1960s dry and wet climate in China witnessed abrupt changes, changing wetness into dryness. Dry and wet climate boundaries show the fluctuation characteristics of the whole shifts and the opposite fluctuations of eastward, westward, southward and northward directions. The fluctuations of climatic boundaries and the dry and wet variations of climate have distinctive interdecadal features.     

近50年气候驱动下东北地区玉米生产潜力时空演变分析

利用GAEZ模型,综合考虑气象、土壤、地形等因素,估算1961-2010年东北玉米生产潜力,分析50年来气候变化导致的东北玉米生产潜力时空格局演变特征。研究发现：① 1961-2010年,东北玉米平均生产潜力波动较大,整体上以每10年80 kg/hm²的线性倾向率增加;② 由于气候变化,20世纪末、21世纪初玉米生产潜力变化较为频繁;③ 玉米生产潜力总值黑龙江省始终处于最高,近50年间增长幅度黑龙江省>吉林省>辽宁省;④ 近50年来,黑龙江省玉米生产潜力的波动较为剧烈,吉林省和辽宁省相对稳定;⑤ 近50年东北玉米适宜种植区有所增加,主要集中在黑龙江省西北地区,高生产潜力区域增加明显,呈现北移趋势。研究可为东北地区高效利用气候和土地资源,优化玉米生产布局提供依据。     

气候变化对东北地区玉米生产的影响

利用气象观测数据、玉米产量及面积资料,分析了东北地区气候变化事实及对玉米生产的影响。研究表明:1971年以来,东北地区≥10℃积温增加了262.8℃,≥10℃积温带(以2700℃为例)平原区向北推进了约200～300km左右,向东扩展50～150km。1991年开始玉米生长季(4～9月)降水量持续减少,年平均水分亏缺量达391.5mm,湿润区缩小,有变干趋势。初霜日推后7～9天,无霜期延长了14～21天,霜冻灾害几率降低。20世纪90年代后,玉米延迟型冷害进入低发期。随着热量资源的增加,玉米可种植区范围不断扩大,种植北界北移东扩,玉米适播起始时间提前。玉米总产、播种面积增加趋势分别为967万t/10a、72万hm2/10a。未来40年东北地区玉米产量以减产为主,与过去30年(1961～1990年)相比平均减产9.5%左右。调整玉米种植布局和品种搭配,依靠水利工程和推广旱作农业技术,选种耐旱、抗病、抗逆性强的玉米品种,是实现东北玉米生产可持续发展的主要措施。     

Rainfall variability,rainfed agriculture and degree of human marginality in North Guanajuato,Mexico

Mexico has a heterogeneous climate due to its geographical location. Half of the Mexican territory is dryland, mostly in the centre and north of the country, within which agriculture is the main activity in the primary production sector. At present, climate variability has a strong impact on Mexican agriculture. This study analysed rainfall variability, its impact on the agricultural productivity in terms of harvested quantity and productivity of 1996‐2014, and in parallel, the role that socioeconomic development plays on the well‐being of the population who live in areas with rainfed agriculture and a semi‐dry climate. The data obtained were analysed with the Statistical Analysis System. A positive correlation was found between rainfall and productivity (r = 0.76 for maize; r = 0.711 for beans). Rainfall variations therefore have a great impact on agricultural productivity, on food security and on the economy. Besides production losses, a parallel consequence is marginalization of the population because producers' income is increasingly reduced due to smaller crop volumes.     

湖北省近500年区域干湿序列重建及其比较分析

在历史旱涝记载资料可靠性检验的基础上,重建了湖北省3个区域近500年来的干湿气候变化序列,并比较分析了各区域干湿气候变化的趋势特征、准周期性及跃变现象。结果表明:在3个区域中,鄂东区1570~1770、1890~1950年两个时段偏湿,1470~1520、1790~1830年则偏干;鄂北区偏湿时期主要在1470~1530、1710~1750、1850~1910年三个时段,1470~1530、1770~1830年则偏干;鄂西南区有1550~1610、1650~1710、1830~1890、1930~1990年4个主要偏湿时期,而无明显的偏干时段。运用功率谱和小波分析对3个干湿序列研究后发现,3个区域干湿变化具有多个气象周期,区域间周期类型差异显著,但50~70年左右的周期在3个区域上均表现突出;采用滑动t检验方法辨识干湿气候跃变现象,在世纪尺度和 30年尺度上检测到各区域干湿变化存在多个跃变事件,且同一跃变事件对不同区域向干(或向湿)影响的趋势相同。     

中国北方地区40年来湿润指数和气候干湿带界线的变化

本文研究了中国北方地区 196 1～ 2 0 0 0年 4 0年间气候干湿带界线分布和 10年际变化。 4 0年来中国北方地区 ,在东经 10 0°以东地区 ,半干旱区和半湿润区的分界线不断波动向东推进 ,2 0世纪 90年代比 6 0年代向东和向南扩展 ,半干旱区面积扩大 ,半湿润区面积缩小 ,气候趋向干旱化 ;东经 10 0°以西地区 ,极端干旱区面积在缩小 ,湿润指数有增大趋势。如果把温度和湿润指数相结合 ,东经 10 0°以东的黄淮海区和黄土高原区为持续的干暖型 ;东经 10 0°以西的西北地区 ,则由干暖型向湿暖型转变 :河西走廊和东疆盆地转型的时间发生在 2 0世纪 70年代初 ,北疆山地绿洲荒漠地区转型的时间发生 2 0世纪 80年代中期前后。气候干湿带界线的变化取决于降水和潜在蒸发的变化速率。 4 0年来 ,在东经 10 0°以东地区 ,降水和潜在蒸发都呈下降趋势 ,但降水减少速率大于潜在蒸发下降速率 ;在东经 10 0°以西地区变湿的原因 ,研究认为除了降水有所增加外 ,潜在蒸发也在下降 ,而且潜在蒸发下降速率的绝对值大于降水增加速率。     

气候变化背景下中国玉米生产潜力变化特征

玉米作为中国第一大粮食作物,探究其生产潜力在气候变化背景下的时空变化特征对中国有效应对气候变化具有重要意义。论文结合全球农业生态区模型、极点对称模态分解方法和集对分析方法,探讨了中国玉米生产潜力的周期性波动特征及长期变化趋势,进而分析了其空间格局演变过程。结果表明：1960—2010年间,中国玉米生产潜力呈增加趋势,由1960年代的9.10亿t增至2000年代的9.45亿t左右。在年际尺度上,中国玉米生产潜力主要以准3 a和准5 a的周期进行波动;在年代际尺度上,存在准10 a和准20 a的波动周期。其中,准3 a的周期波动是中国玉米生产潜力长时间变化的最主要特征,这主要是受年降水量变化的影响。从空间格局来看,中国玉米生长适宜区主要集中在加格达奇—锡林浩特—临河—西宁—天水—中甸沿线以东;1960—2000年间,玉米生产潜力界线在中国东北部和临河—西宁沿线发生了较为明显的移动。华北平原、辽河平原、四川盆地等地区的玉米单产潜力变化趋势具有较强的一致性,松嫩平原、三江平原、关中盆地、长江中下游平原等地区的玉米单产潜力变化过程与上述地区恰好相反。在这2类地区,玉米单产潜力的变化均较显著,但变化方向在年代际尺度上具有交替性。     

亚洲季风与中国干湿、农牧气候界线之关系

基于中国553个气象站点1958~2000年日降水量资料、北方295个气象站点同期(20(cm)蒸发皿资料,界定出半干旱区和农牧交错区各自的范围。利用东亚夏季风强度指数(1951~1995年)与印度夏季降水量(1951~1998年)资料, 分析了半干旱区和农牧交错区东南-西北界10年际空间变化与亚洲夏季风的关系。近50年中国干湿、农牧气候界线的动态变化是影响中国的季风环流强弱作用在空间上的实物表现, 季风环流的强弱变化控制着气候界线空间摆动的范围与方向, 其年代际变化是中国干湿、农牧气候界线呈现出年代际变化特征的根源。分析显示, 在现代情况下, 农牧气候界线位置的空间摆动主要反映人类生产活动强度的强弱差异, 人为因素起主导作用。     

Agricultural Climate Change and Wetland Agriculture Study under the Climate Change in the Sanjiang Plain

With linear curvefitting, Mann-kendall method and Yamamoto method, ≥10 ℃accumulated temperature and precipitation from May to September of 6 meteorological stations (Baoqing, fujin, Jiamusi, Hegang, Jixi and Hulin) from 1978 to 2007 were used to explore 30-year agricultural climate change and trend in the Sanjiang Plain. The results showed that ≥10 ℃ accumulated temperature of the 6 stations have risen by 141.0 ℃ to 287.4 ℃ when estimated by their significant linear trends (n=30, α=0.05) over the last 30 years (1978 to 2007). The rates of warming for the last 30 years range from 4.70 ℃per year to 9.58 ℃ per year. There are not significant linear trends on precipitation from May to September of the 6 stations over the last 30 years. The period of 1978 to 1998 in which ≥10 ℃ accumulated temperature is lower is consistent with that in which there is more precipitation from May to September, and warming and drying period has occurred in the Sanjiang Plain since 1999. Under the background of warming and drying agricultural climate, high yield cultivation of Phragmites australis and establishment of Phragmites australis-fish (crab) symbiosis ecosystem in natural mire are the ways for reasonable use of natural wetland. The area of paddy fields has been increasing from 7.25×104 ha in 1978 to 121.2×104 ha in 2006. It is proposed that paddy field range should not be expanded blindly toward the north in the Sanjiang Plain, and chilling injury forecast and prevention should be pay attention to. In the area that the chilling injury happens frequently, the rotation between rice and other crops should be implemented. Measures, which combine drainage, store and irrigation, should be taken instead of single drainage on comprehensive control of regional low and wet croplands to ensure controlling drought and flood.     

气候变化对石羊河、大凌河流域灌溉玉米生产的影响

全球气候变化及其影响越来越受到广泛关注,生态环境已相对恶化的地区未来将可能更加脆弱.选取生态环境已十分脆弱的石羊河和大凌河流域,采用区域气候模式与CERES-Maize模型相结合的方法,模拟分析了基准气候(BS,1961-1990年)和A2、B2两种气候变化情景下2011-2100年2个流域灌溉玉米生产的变化,以了解未...     

我国玉米对气候变化的敏感性和脆弱性研究

文章利用英国Hadley中心PRECIS模型输出的B2气候情景格点数据,输入CERES_Maize作物模型,对我国未来(2 070 s)不同格点玉米产量进行预测,并依据产量的变化率和GIS技术对我国未来玉米气候变化的敏感性和脆弱性进行研究,找出了未来我国玉米的气候变化敏感区和脆弱区,对指导我国不同玉米生产区有效适应未来气候变化具有重要的科学意义。     

Climate spatial variability and data resolution in a semi-arid watershed, south-eastern Arizona

In the 10,000 km² San Pedro River watershed area in south-eastern Arizona, high-resolution spatial patterns of long-term precipitation and temperature were better reproduced by kriging climate data with elevation as external drift (KED) than by multiple linear regression on station location and elevation as judged by the spatial distribution of interpolation error. Mean errors were similar overall, and interpolation accuracy for both methods increased with increasing correlation between climate variables and elevation. Uncertainty in station locations had negligible effect on mean estimation error, although error for individual stations varied as much as 27%. Our future ability to examine spatial aspects of climate change at high spatial resolution will be severely limited by continuing closures of climate stations in this part of the United States.     

The influence of climate change on maize production in the semi-humid–semi-arid areas of Kenya

The effect of climate change on maize production in the semi-humid and semi-arid, agro-climatic zones III-IV of Kenya was evaluated using two General Circulation Models (GCMs): the Canadian Climate Center Model (CCCM) and the Geophysical Fluid Dynamics Laboratory (GFDL), as well as the CERES-Maize model. Long-term climate data was obtained from three meteorological stations situated in eastern, central and western regions of Kenya, while maize data was obtained from six sites within the regions. The climate scenarios were projected to the year 2030. Temperature increases of 2·29 and 2·89°C are predicted by the CCCM and GFDL, respectively. Rainfall levels are predicted to remain unchanged, but there are thought to be shifts in distribution. It is predicted that the short-rains season (October–January) will experience some increased rainfall, while the long-rains season (April–July) will show a decrease. Maize yields are predicted to decrease in zone III areas, while an increase is predicted in zone IV areas. However, the predicted changes in yields are low since they all fall below 500 kg ha⁻¹, except the Homa Bay site. Thus, to counter the adverse effects of climate change on maize production, it may be necessary to use early maturing cultivars, practice early planting, and in eastern Kenya, shift to growing maize during the short-rains season.     

Changes in climatic variability and maize yield inNortheast China

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Issues of Spatial and Temporal Variability in Climate Impact Studies

The accuracy of impact estimates relating climate change to regional-scale agricultural production is constrained by the temporal and spatial resolution of climate change projections. Several techniques have been used to compensate for these limitations in order to provide reasonable estimates of the impact of climate change on crop yield. One approach assumes that variability over time can substitute for spatial variability, thereby reducing the need to estimate the impacts at a spatially dense network of stations—an assumption that has not been generally tested. This study evaluates this assumption using methods similar to those employed in the climate impact literature. The findings suggest that current practices are generally defensible if the goal is to provide a range of possible crop responses to climate change. However, the results also show that the assumption is highly sensitive to specific interactions at the soil-plant-atmosphere interface and, consequently, does not hold under certain circumstances.     

气候暖干化背景下甘肃旱作区玉米气候适宜性变化

运用甘肃旱作区5 个农业气象试验站及农业气象观测站1981-2008 年的玉米平均物候资料及相同地点气象站1971-2008 年的逐日气象资料,建立了玉米各个气候因子适宜度及综合气候适宜度计算模型,对1971-2008 年玉米全生育期及各主要玉米生育阶段的气候因子及综合气候适宜度进行了计算分析。结果表明,自1971 年以来,玉米全生育期温度、光照适宜度呈上升趋势,降水适宜度呈下降趋势。各气候因子组合效果趋好。全生育期内,以播种-出苗期及抽雄期-乳熟期各气候因子的组合效果较差,拔节期-抽雄期及乳熟期-成熟期各气候因子的组合效果较好。播种-出苗期光照、温度适宜度随年份线性变化不明显,降水适宜度逐年线性降低,综合气候适宜性逐年变差。出苗期-拔节期、乳熟期-成熟期光照适宜度随年份呈上升趋势,降水适宜度呈下降趋势,综合气候适宜度呈下降趋势。拔节期-抽雄期光照、温度适宜度随年份呈上升趋势,降水适宜度随年份线性变化不明显,综合气候适宜度呈上升趋势。抽雄期-乳熟期光照适宜度随年份呈下降趋势,降水适宜度呈上升趋势,温度适宜度线性变化不明显。综合气候适宜度呈上升趋势。出苗期-拔节期、拔节期-抽雄期及抽雄期-乳熟期的光照适宜度与产量相关性比较显著,播种-出苗期及抽雄期-乳熟期的温度适宜度与产量相关性比较显著,拔节期-抽雄期及抽雄期-乳熟期的降水适宜度与产量相关性显著。未来温度适宜性变好,气候变化利于玉米生长发育