黑龙江省近40年夏季季风的变化规律

为了分析黑龙江省夏季季风的变化规律和夏季季风与年降水之间关系的变化,采用Samel发明的方法,用逐日降雨量数据计算每一年夏季季风到达、离开、停留在黑龙江省的时间。研究结果显示:在1960年至2000年间,黑龙江省的年降水量变化趋势是每10a增加2.229mm,这一变化趋势不显著;夏季季风停留的时间和季风期间的降水量呈显著减少的趋势,分别为每10a减少6.9d和17.5mm。夏季季风这一变化主要原因在于1960–1975期间是夏季季风离开该省的时间提前,1990–2000年间是到达该省的时间拖后。夏季季风在过去40a的减弱使它对年降水量的贡献率每10a减少4.4%。     

陕西省气温和降水时空变化特征

利用陕西省1960-2013年气象资料,分析了气温和降水时空变化特征。结果表明:(1)在时间尺度上,陕西省的年平均气温的上升速率约为0.23℃/10 a,1990年代后期以来,气温显著升高。四季气温也呈上升趋势,其中春、冬季上升速率较大。年降水量以8.78 mm/10 a的速率下降,1980年代后期以来,降水量明显减少。春、秋季降水量呈下降趋势,夏、冬季呈上升趋势。年平均气温在1996年发生突变,1996年以来为高温期,年降水量在1970年和1975年发生突变,1970年以来为相对少雨期。在10年尺度上,陕西省气候依次经历了冷湿—冷干—冷湿—暖干—暖干的变化过程,暖干化趋势明显。(2)在空间尺度上,年平均气温由南向北递减,呈现出明显的纬度地带性特征。年降水量整体由南向北递减,部分山地形成地形雨。(3)北半球中高纬度的环流系统的变化和ENSO事件是影响陕西省气候变化的重要因素。     

广东省未来温度、降水及陆地生态系统NPP预测分析

气候变化模型模拟是预测未来气候因子变化的有效方式之一.文章利用CCSM3大气环流模型,模拟了广东省1980～2099年月平均温度和月降水量多边形格网shape数据,并使用ArcGIS软件统计每个格网每年的平均温度和年降水量,再通过统计所有格网的均值,得到整个广东省的年平均温度和降水量.通过比较2000～2099年五个阶...     

1990-2012年山东济南市气候变化特征分析

根据济南市1990-2012年气象数据,运用均值、线性倾向估计等统计分析的方法,对济南气温和降水的季、年变化特征进行了分析。结果表明：济南市近25年平均气温为14．96℃,并以0．153℃／5a的速度下降,与全球气温上升趋势不一致,各季节平均气温变化不一,但整体均呈现下降趋势,降温幅度冬季〉夏季〉秋季〉春季;20多年来其平均降水量为850．58mm,以22．86mm／5a的速率递减,秋季和冬季降水量趋于平衡,春季有明显上升趋势,夏季呈现减少趋势,极值之差为187．2mm。     

Summer precipitation influences the stable oxygen and carbon isotopic composition of tree-ring cellulose in Pinus ponderosa

The carbon and oxygen isotopic composition of tree-ring cellulose was examined in ponderosa pine (Pinus ponderosa Dougl.) trees in the western USA to study seasonal patterns of precipitation inputs. Two sites (California and Oregon) had minimal summer rainfall inputs, whereas a third site (Arizona) received as much as 70% of its annual precipitation during the summer months (North American monsoon). For the Arizona site, both the delta(18)O and delta(13)C values of latewood cellulose increased as the fraction of annual precipitation occurring in the summer (July through September) increased. There were no trends in latewood cellulose delta(18)O with the absolute amount of summer rain at any site. The delta(13)C composition of latewood cellulose declined with increasing total water year precipitation for all sites. Years with below-average total precipitation tended to have a higher proportion of their annual water inputs during the summer months. Relative humidity was negatively correlated with latewood cellulose delta(13)C at all sites. Trees at the Arizona site produced latewood cellulose that was significantly more enriched in (18)O compared with trees at the Oregon or California site, implying a greater reliance on an (18)O-enriched water source. Thus, tree-ring records of cellulose delta(18)O and delta(13)C may provide useful proxy information about seasonal precipitation inputs and the variability and intensity of the North American monsoon.     

Enhanced growth of Juniperus thurifera under a warmer climate is explained by a positive carbon gain under cold and drought

Juniperus thurifera L. is an endemic conifer of the western Mediterranean Basin where it is subjected to a severe climatic stress characterized by low winter temperatures and summer drought. Given the trend of increased warming-induced drought stress in this area and the climatic sensitivity of this species, we expect a negative impact of climate change on growth and ecophysiological performance of J. thurifera in the harsh environments where it dominates. To evaluate this, we measured long- and short-term radial growth using dendrochronology, photosynthesis and water-use efficiency in males, females and juveniles in three sites in Central Spain. Climate was monitored and completed with historical records. Mean annual temperature has increased +0.2?°C per decade in the study area, and the main warming trends corresponded to spring (+0.2?°C per decade) and summer (+0.3?°C per decade). Radial growth and maximum photosynthesis peaked in spring and autumn. Positive photosynthetic rates were maintained all year long, albeit at reduced rates in winter and summer. Radial growth was enhanced by wet conditions in the previous autumn and by warm springs and high precipitation in summer of the year of tree-ring formation. Cloud cover during the summer increased growth, while cloudy winters led to impaired carbon gain and reduced growth in the long term. We argue that maintenance of carbon gain under harsh conditions (low winter temperatures and dry summer months) and plastic xylogenesis underlie J. thurifera's ability to profit from changing climatic conditions such as earlier spring onset and erratic summer rainfall. Our results highlight that not only the magnitude but also the sign of the impact of climate change on growth and persistence of Mediterranean trees is species specific.     

61年来滇西南地区干热河谷与热带雨林地区气候变化分析

根据元江和勐腊两地区1957—2018年的气候数据资料,采用线性趋势估计、累积距平法、Mann-Kendall突变检验法和小波分析法等方法,分析这两个区域气候和干、湿季变化趋势,探讨元江和勐腊地区气候因子的突变情况及变化周期.结果表明:(1)1957—2018年以来,干热河谷元江地区和热带雨林勐腊地区气温变化与西南地区...     

近60年来西双版纳气候变化及其与橡胶种植关系研究

近年来西双版纳大范围的橡胶种植给当地生态环境带来严重影响。利用1957—2017年西双版纳州勐腊县的气候资料以及1980—2017年橡胶种植面积数据,采用气候倾向率估计、滑动t检验和Pearson相关系数等分析方法,研究气候变化特征及其与橡胶种植的关系。结果表明,1957—2017年勐腊县多年平均气温、最高气温、最低气温、相对湿度、降水量、日降水量≥0.1 mm日数分别为21.5℃、29.0℃、17.6℃、83.7%、1528.78 mm和160.7 d;气温、最高气温、最低气温随时间变化呈现显著的上升趋势,相对湿度和降水日数则呈现显著的下降趋势,降水量稍有增加,但增加不明显;西双版纳气候呈现显著的干热化趋势,且干热化趋势在1980年代明显增强,至2000年代中期以后进一步增强;1980年以来,橡胶林种植面积快速增大,且其随时间增大的趋势与当地干热化趋势基本一致;西双版纳橡胶种植面积与气候要素均具有显著的相关关系,大范围橡胶种植在当地气温上升和相对湿度减小的变化中发挥着显著的作用。     

鼎湖山亚热带季风常绿阔叶林蒸散研究

运用Penman蒸散力公式和理论上导上导出的计算森林生态系统蒸散公式，对亚热睦带性群落鼎湖山季风常绿阔叶林的蒸散力和蒸散逐日进行计算，其结果表明：鼎湖山季风常绿阔叶林蒸散力年平均为９８７．５mm占同期降雨量的４７％，蒸散力最大的月分是７月，最小的月份是２月，这样基本上与近地面层的气温度变化规律相一致，而与同期的降雨量有所延迟。林外自由水面蒸发年平均为１１９４．５mm干季林内蒸散力明显小于林外自由水面的蒸发，而湿季两者又十分接近，因此，两者相比可用来作为该地区划分干湿季的一个参指标，理论公式法所计算出该系统的蒸散年平均为９５１．９mm,与蒸散力相当，占同期降雨量的４５．３％。鼎湖山季风常绿阔叶林总径流量年平均为１１０３．８mm，径流系数为０．５２，研究期间系统贮水量的变经年平均为３８．９mm.水量平均法所得的蒸散年平均为９６０．１mm与公式法计算所得的蒸散非常接近，３年的系统误差不到１５，因此，初步得出此公式是计算森林生态系统蒸散的一种值得推广的方法。     

气候变化背景下云南松林火灾害的响应规律研究

基于1990—2018年云南省云南松分布区气象数据和森林火灾数据,采用Mann-Kendall趋势检验法、对比分析法以及相关性分析研究气象指标与森林火灾的动态变化趋势和响应规律.结果表明:(1)防火期平均气温在1998—2018年达显著上升水平,年均与防火期的平均相对湿度均在1995—2018年达显著下降水平;年均及防...     

滇中华山松人工林的水文特征及水量平衡

根据滇中高原的华山松林集水区径流场连续 3a的降雨和径流观测数据 ,进行了华山松人工林的水文特征及水量平衡的研究。结果表明 :( 1)本区域降水量的季节分配不均 ,湿季 ( 6～ 10月 )降水量占全年的 80 % ,降水量主要由大于 10mm以上的降雨带来 ,且降雨强度大部分小于 5.0mm·h- 1。 ( 2 )集水区年平均降雨量 10 0 5.6mm ,在林冠作用面降雨量的分配中 ,林冠截留雨量 2 10 .6mm ,截留率 2 0 .9% ;穿透过林冠层的降雨 74 5.3mm ,树干茎流量 4 9.7mm ,分别占降雨量的 74 .2 %和 4 .9%。 ( 3)集水区径流的月变化滞后于降雨 ,总径流量 172 .2 9mm ,总径流系数 17.13% ,其中 ,地表径流 8.0 3mm ,地下径流 164.2 6mm ;地表径流主要集中在雨季产生 ,一次性降雨对地表径流的影响显著 (R =0 .91)。 ( 4 )土壤蓄水年变化量 11.2mm ,约占年降水量的 1.1% ,但月变化较大 ;系统水量最大的输出是蒸散 ,每年以气态形式返回大气的水量 82 2 .1mm ,占降水量的 81.8% ;在蒸散的水量中 ,林冠截留雨量的直接物理蒸发量 2 10 .6mm ,占总蒸散量的 2 5.6%。     

Temperature sum accumulation effects on within-population variation and long-term trends in date of bud burst of European white birch (Betula pendula)

Within-population variation in phenology of boreal trees indicates their adaptability to climatic variations. Although interannual variations in date of bud burst have been widely discussed, little is known about within-population variation, the key determinants for this variation and the effects of this variation on estimates of trends in bud burst date. Over a period of nine years, we monitored timing of bud burst daily in 30 mature white birch (Betula pendula Roth) trees in a naturally regenerated stand. Our results revealed not only large interannual variation but also considerable intraannual variation among individual trees in date of bud burst, the maximum within-population variation being four weeks. Bud burst can be accurately predicted by the date when a threshold value of temperature sum in spring is reached (base temperature +5 degrees C). Based on this temperature sum and past temperature records, we estimated the trend in date of bud burst. The linear trend estimate based on the years 1926-2005 is an advancement of 1.2 days per decade (95% confidence interval, +/- 0.7 days), which is much less than that predicted by time series based on coarser time intervals. We conclude that, because of large interannual differences, and large annual within-population variations in bud burst, estimates of bud burst date based on measurements made over a period of only a few decades are unreliable.     

模拟增雨对荒漠灌木白刺枝叶生长的促进作用

根据年均降水量,分别在乌兰布和沙漠东北缘(内蒙古磴口,年均降水145 mm)和巴丹吉林沙漠东南缘(甘肃民勤,年均降水115 mm)对天然白刺灌丛进行不同梯度的增雨实验(年均降水量的0％、25％、50％、75％、100％).结果表明:增雨的比例越大,白刺形态特征的变化越明显;100％增雨对磴口和民勤白刺形态特征的影响最明显,能够显著增加白刺标记枝的长度、直径和干质量,但是对成熟叶片和新叶片数的影响不显著;增雨还显著增加了9月磴口和民勤白刺枝叶的干质量和鲜质量;在较干旱的民勤地区,较大的增雨量才能促进白刺枝条生长;50％增雨即可促进夏末磴口白刺枝条生物量增加,75％增雨才能促进夏末民勤白刺枝条生物量增加.     

成都市土地利用时空结构变化研究

随着经济的高速发展,城市化对土地利用结构变化的影响较大,土地利用时空结构变化研究对土地规划及可持续发展具有重要意义.本文对成都市2000—2020年的土地利用数据进行处理,计算土地利用年变化率(R)、土地利用程度综合指数和土地利用变化量(S),得出以下结论:(1)耕地和建设用地变化幅度较大,总体呈增大的趋势;林地和其他...     

海南岛尖峰岭热带林生态系统研究(续)——Ⅲ.热带林水热状况Ⅳ.热带林物质循环

热带林的反射率平均占辐射量的17.4％,向大气的有效长波辐射约占13.7％,净辐射约占70％。蒸散值约占年降水量的36—57％,平均为43.6％。水量平衡各分量、土壤CO_2释放量、森林小气候特征都与干湿季节的变化有明显的关系。山地雨林的年凋落物量平均为7.7±1.2t/ha,半落叶季雨林为9.7±2.3t/ha。物质循环的研究表明,热带林的有机物归还量大、分解快,在较少人为干扰下元素的输出较少,多用于系统内的循环利用。     

Ecological Environment Change in North Slope of Qilianshan Mountains

Based on meteorological,hydrological, forest,and grassland data collected by location observation,remote sensing,field surveys and relevant literature during 1956 to 2009,the ecological environment change in northern slope of the Qilianshan Mountains was analyzed synthetically using regression and correlation analyses.The results showed that the temperature had an annual variation rate of 0.033 4℃·a^-1 in northern slope of the Qilianshan Mountains since 1960,and exhibited a raising trend,especially since 1987.The annual variation rate of annual precipitation was 0.570 2 mm·a^-1,indicating that the precipitation tended to increase.The climate had changed from arid to humid in this region since 1976.From 1956 to 2006,the glacier area of six inland river basin（Shiyanghe river,Heihe river, Beidahe river,Shulehe river,Danghe river and Halternhe river） and Datonghe river basin in northern slope of Qilianshan mountains decreased by 17.7%. Thickness of the glacier reduced about 5-20 m,and the snow line rose about 100-140 m.The Glacier ice reserves in inland river basin of Hexi decreased by 11.4%.From 1972 to 2007,27 glaciers in the eastern section of the Qilianshan Mountains disappeared.From 1956 to 2009,the runoff change in the northern slope of the Qilianshan Mountains was different in different regions.The runoff was reduced significantly in Shiyanghe river basin, increased slightly in Heihe river basin,and increased obviously in Shulehe river basin.From 1958 to 1988, the area of deforestation and farming was more than 10.0 million ha,and the forest area was reduced 0.6 million ha.Since the Qilianshan Mountain Nature Reserve was established in 1989, the forest was restoring gradually because of continual protection and cultivating,and the forest area was increased 9.4 million ha from 1989 to 2008. Due to human interference,especially over-grazing impact,the quality of the wood-land,shrub-land and grass-land in northern slope of the Qilianshan Mountains were in a degraded condition,which re     

干热河谷和干性森林水分特征的对比分析

本文研究了川西南山地安宁河流域干热河谷和干性森林的水分收支状况。结果表明:(1)干热河谷和干性森林的年降水量分别为1 067.95 mm和1 371.73 mm,年降水量的90%以上集中在6月～10月的雨季和夏秋季节;(2)干热河谷和干性森林年蒸发量为1 280 mm和1 089.75 mm,春夏蒸发占年蒸发量的65%和66%,旱季蒸发占年蒸发量的58%和61%,4月～6月是蒸发旺季,其次是7月～8月;(3)干热河谷和干性森林年水分盈余量分别为43.6 mm和481.95 mm,均存在季节性水分匮缺期,7月～10月、夏秋季节和雨季均是水分盈余期,其余为水分匮缺期;(4)干热河谷和干性森林年干燥度分别为1.205和0.8,表明该地区分别为半湿润和湿润性气候,还存在明显的季节差异,7月～10月、雨季和夏秋季节气候湿润,其余时期为半湿润或干旱气候;(5)干性森林在年降水量和水分盈余量上高于干热河谷,在年可能蒸发量和干燥度上明显低于干热河谷,这种差异还体现在水分参数的月分配、四季分配、旱雨季分配上;(6)干热河谷湿润程度差于干性森林,干热河谷植被和干性森林对各自水分收支状况具有良好的适应性;(7)封山育林需要注意旱季防火,人工促进还需要考虑土壤水分平衡规律和适地适树,进行"适度"造林。     

乌兰布和沙漠东北部干旱指数的变化特征

利用磴口县1954-2005年的降水、蒸发资料，分析该地区四季干旱指数的变化特征。研究表明，该地区气候以干旱为主，且持续时间长，最长达14a之久。冬季与春季以重旱为主，重旱频率分别为40．4％与36．5％；夏季以中旱为主，中旱频率为38．5％；秋季重旱与中旱频率一致，为32．7％。这种气候特点与该地区降水主要集中在夏季有关。以年代际划分，70年代春季干旱最为严重，80年代夏季干旱最为严重，60、90年代秋季干旱最为严重，60、80及90年代冬季干旱最为严重。     

气候变化情景下毛竹潜在分布及动态预测

为探究毛竹的潜在分布及其动态变化，并确定对其分布起主导作用的环境变量，文章基于MaxEnt预测模型，利用环境变量图层及316个毛竹分布点数据研究毛竹地理分布的变化。结果显示：1）限制毛竹分布的主要环境变量为最干月降水量、年均降水量、最冷月最低温、年平均温、温度年较差和海拔；2）当前毛竹的潜在适生区主要位于中国东南部，与亚热带季风气候区大致重叠，高适生区主要位于总适生区的东部和西北部；3）在未来气候情景下，毛竹总适生区面积有所缩减，各不同等级适生区面积变化大，其中高适生区面积大幅度缩减。研究获得的毛竹适生区变化趋势可为毛竹培育、引种以及入侵防治提供参考。