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1.
利用喀什国家基准气候站1982～2010年的气象观测数据和地面物候观测资料,采用气候倾向率和气候趋势系数方法,分析气温、降水、日照时数的变化特征以及其对新疆常见的5种木本树种物候期的影响.结果表明:近29年来喀什气候增暖,气温、降水量和日照时数等基本气象要素的增加趋势较明显,年平均气温和年总降水量的增幅分别为0.37～1.10℃/10a和12.14mm/10a;以季节而言,在春季气温和日照时数的升幅最大,降水量在秋季较明显.这种气候变暖的趋势与5种树物候期有密切相关,春季气温和春季日照时数的增多使物候期提前,而秋季的降水量促进木本植物的生长,使物候期延迟. 相似文献
2.
1981-2006年西北干旱区NDVI时空分布变化对水热条件的响应 总被引：5，自引：1，他引：4
气候是植被变化的重要驱动因子. 利用1981-2006年GIMMS归一化植被指数（NDVI）时间序列数据,结合68个气象站降水、气温数据和DEM地形数据等资料,研究分析了西北干旱区植被活动的年、季变化和空间差异. 结果显示：在1981-2006年的26 a,西北干旱区植被的覆盖率增加了4.5%,年平均NDVI增加了3.2%;植被的生长季延长,主要表现在生长季的推迟. 从总体来说,植被覆盖率、生长季和NDVI值在2000年以前显著增加,而在2000年以后都呈现减小的趋势;其中,减少明显的区域是在伊犁河谷、中天山及平原区,在河流上游山区或源头以及部分河流两岸呈现增加态势;在年际变化上,大部分区域的气温、降水与NDVI相关性不强. 而年平均气温在4.58 ℃以下低温区和年降水在180 mm以上的相对湿润区,气温和降水都呈现正相关;在季节变化上,NDVI值在春季和秋季与温度相关显著,而夏季与降水相关性强. 2000年以后,植被覆盖率和NDVI值开始出现降低趋势与气温持续升高、降水量增幅下降有关. 相似文献
3.
植被物候是指示植被对自然环境变化响应的重要指标。大兴安岭多年冻土区是我国唯一的高纬度多年冻土区,该区植被物候的研究有助于认识寒区生态系统对全球气候变化的响应。本文首先比较了归一化植被指数(NDVI)、增强型植被指数(EVI)和日光诱导叶绿素荧光(SIF)在多年冻土区物候研究中的差异和适应性,结果表明EVI的应用效果最佳。其次,结合2000—2019年MODIS EVI时间序列数据和气象数据,采用Savitzky-Golay(S-G)滤波和动态阈值等方法提取植被生长季开始(SOS)、结束(EOS)和长度(LOS)等关键物候参数,分析大兴安岭多年冻土区植被物候的时空变化及其对气候变化的响应。结果表明:(1)NDVI、EVI和SIF的时间序列均能反映研究区植被生长的季节变化,与NDVI相比,EVI与SIF的变化曲线更加一致。(2)研究区2000—2019年SOS变化范围为年序日96~144 d,平均值为129.46 d。EOS变化范围为272~320 d,平均值为295 d。LOS集中分布在128~224 d,平均值为165.65 d。由于植被类型差异和逆温现象的存在,大片连续多年冻土区的LOS大于岛状融区多年冻土区。(3)研究区SOS和EOS变化趋势的平均值分别为-1.23 d·(20a)^(-1)和-0.46 d·(20a)^(-1),均呈提前趋势。LOS变化趋势的平均值为2.39 d·(20a)^(-1),呈延长趋势。研究区植被SOS与3—5月平均气温呈显著负相关,EOS与8—10月平均气温和降水呈显著正相关。 相似文献
4.
文章根据清代王闿运所著《湘绮楼日记》中的湖南长沙、衡阳地区的春季物候记录,重建了该地区1888～ 1916年的春季植物物候距平序列。分析发现,1888～1916年春季植物物候期平均较现代推迟3.22d,其中1890年 代迟4.89d,1900年代迟2.22d,1910年代迟4.29d。进而推算,长沙、衡阳地区1888～1916年的春季比现代冷,平 均气温低0.37℃。该结果可使长沙地区的年代际春季温度序列延长到1890年代。 相似文献
5.
近20年气候变暖对北京时令旅游的影响——以北京市植物园桃花节为例 总被引：9，自引：0，他引：9
北京植物园桃花节是赏花专题时令旅游的典型代表,以近20年植物园桃花节的起讫时间、持续时间及相关气温、物候期等数据为依据，探讨了气候变暖对时令旅游的影响。结果表明：1994年前后桃花节开始日期存在着显著的均值差异，后一时段比前一时段约提前6天，植物园桃花节的开始日期在总体上响应了以山桃始花为代表的北京春季物候提前的变化趋势。同时，桃花节开始日期与上年山桃始花日期、上年年均温度存在显著相关性，反映人们对桃花节的决策是参照上一年的物候现象做出的，相对于气候年际波动存在1年的滞后。桃花节结束日期受人为因素影响较大，但总的来说气候变暖有利于桃花节持续日数的延长。此外，桃花节响应气候变化的滞后性，使得气候波动容易引起时令旅游产品的不稳定，不利于时令旅游的经济效益和社会效益。 相似文献
6.
作为长江、黄河、澜沧江的发源地,三江源区是我国重要的水源涵养区和生态屏障。在气候变化背景下,三江源区广泛分布的冻土显著退化,对植被变化与生态环境产生深远影响,但近20年植被变化特征及其对气候与冻土变化的响应尚不明晰。基于2001—2020年间三江源区植被、气象与土壤冻融数据集,分析了过去20年间三江源区植被物候变化特征及其对气候因子与土壤冻融要素变化的响应。结果表明：三江源区归一化植被指数(NDVI)整体呈东南高、西北低的空间格局,2001—2020年间三江源区植被整体呈变绿趋势,生长季NDVI以每10年0.017的速率显著增加;植被物候显著变化,生长季延长[6.3 d·(10a)-1],主要由生长季开始日期(SOS)提前[4.9 d·(10a)-1]贡献。基于统计分析结果,气温和降水是生长季NDVI最重要的主导因素,植被对降水的敏感性在气温相对较高、降水相对较少的暖干区域更强;生长季开始前的降水是SOS最重要的主导因素。土壤冻融变化对植被生长的影响具有空间异质性,在暖干区域,土壤融化时段延长对植被生长起到抑制作用。总体来看,三江源季节冻土区... 相似文献
7.
物候对全球变暖响应的研究综述 总被引：73，自引：4，他引：73
近100年来，尤其是在最近20多年，全球平均表面温度出现了显著上升，全球变暖已成为全球关注的重要问题。物候现象与气候等环境因素息息相关，物候对全球变暖的响应研究正在成为物候研究的一个新的热点领域，NDVI正日益成为植被对气候响应研究的重要手段。概述了当前物候对全球变暖响应研究的主要进展。基于实地动植物等物候观测和遥感监测的大量研究表明，近期动植物等物候正发生着显著变化：北半球中高纬度地区植被生长季延长、植物提早开花、昆虫提早出现、鸟类提早产蛋以及冰川退缩、永冻土带融化、江河湖泊结冰推迟而融化提早等，与气候变暖有密切关系，是对全球变暖的明显响应。目前国内的许多研究者在物候对气候变暖响应方面做了一些工作，但与国际研究进展相比，还有许多研究工作有待于进一步开展。 相似文献
8.
额尔齐斯河发源于中国新疆阿尔泰山南坡,是中国唯一流入北冰洋的河流。随着中俄“冰上丝绸之路”提出,额尔齐斯河通航具有重要意义,监测其河冰物候变化显得尤为必要。本研究基于2001—2018年MOD09GQ第2波段数据,分析了额尔齐斯河布尔津至斋桑泊段每年河冰物候信息,包括开始封河时间、结束开河时间、冰/雪最大覆盖时间、冰期持续时间、封河速率和开河速率。研究结果表明：（1）MOD09GQ的反射率随河冰开河而逐渐降低,经与南湾水文站实际观测的冰期持续时间相比较,其所得冰期持续时间与实测冰期持续时间变化一致,均略有延长趋势,这表明MOD09GQ能有效监测河冰物候信息;（2）开始封河时间与结束开河时间均有提前趋势,最早开始封河比最晚开始封河提前45天,最早结束开河比最晚结束开河时间提前31天,开始封河比结束开河提前时间更多,导致整个冰期持续时间有延长趋势;（3）封河速率有变慢趋势,开河速率有逐渐加快趋势,这意味着若未来该河段通航,每年通航期将延长,将带来更大的经济效益。 相似文献
9.
根据采自青海南部高原曲麻莱、治多地区的圆柏树轮样芯建立的树木年轮年表,重建了近450年来高原春季（4～6月）的最高气温序列。采用多窗谱分析、小波分析和Yamamoto突变检测分析等方法综合研究了重建的高原春季最高气温序列的准周期性及多尺度突变特征。结果显示,青海南部高原地区春季最高气温的变化存在较明显的31～54年低频和2～4年高频准周期波动特征。在30～54年时间尺度上,青海南部高原春季最高气温变化经历了1622～1639年、1798～1816年、1896～1913年和1933～1951年的偏冷期以及1684～1703年、1779～1797年、1817～1835年和1914～1932年的偏暖期。分析还发现,青南高原地区春季最高气温在冷暖期的转换过程中存在着较明显突变现象,在30～40年时间尺度上,Tm序列在1610年、1668年、1816年、1915年和1934年前后的突变是明显的。交叉相关分析显示,在滞后7.5年左右,青海南部高原春季最高气温波动与太阳黑子周期长度的变化呈显著负相关。 相似文献
10.
利用经过重建后的 2000～2008年生长季MODIS-NDVI时间序列逐年生长季均值对中国东北样带植被覆盖变化进行了研究,发现植被NDVI变化过程具有明显的时空分异特征.在时间上,2001年与2002年NDVI均值比 2000～2008年9年均值分别偏低1.89%和1.44%,而2003年和2008年分别偏高2.92%和2.87%.在空间上,样带东部半湿润地区植被覆盖在 2000～2008年间年际变化很小,NDVI波动在2%以下.样带中部半干旱区NDVI波动一般低于5%.而样带西部干旱的草原和荒漠化草原区植被覆盖波动明显,NDVI波动于2003年和2008年分别出现了8.51%和6.35%高值,裸地甚至于2003年出现了高达15.07%的波动.研究区NDVI变化的时空分异特征,对遥感研究和生产实践有重要意义.一方面,在进行陆地生态系统变化监测时,不能用少数几次的监测结果预测变化趋势,这对"高空间分辨率-低时间分辨率"遥感数据应用有重要意义; 另一方面,NDVI波动的空间差异,要求在变化监测时把重点放在NDVI波动频繁的地区. 相似文献
11.
Climate change has significantly altered the temperature rhythm which is a key factor for the growth and phenophase of the crop. And temperature change further affects crop water requirement and irrigation system. In the north-west of China, one of the most important crop production bases is Heihe River basin where the observed phenological data is scarce. This study thus first adopted accumulated temperature threshold (ATT) method to define the phenological stages of the crop, and analysed the effect of climate change on phenological stages and water requirement of the crop during growing season. The results indicated the ATT was available for the determination of spring wheat phenological stages. The start dates of all phenological stages became earlier and the growing season length (days) was reduced by 7 days under climate change. During the growing season, water requirement without consideration of phenophase change has been increased by 26.1 mm, while that with consideration of phenophase change was featured in the decrease of water requirement by 50 mm. When temperature increased by 1°C on average, the changes were featured in the 2 days early start date of growing season, 2 days decrease of growing season length, and the 1.4 mm increase of water requirement, respectively. 相似文献
12.
Earlier spring onset and the associated extension of the growing season in high latitudes belong to the most obvious consequences of global warming. The natural dynamics of growing-season properties during past climate shifts however, are extremely difficult to reconstruct since temperature reconstructions are hardly ever seasonally resolved and the applied proxies such as chirinomid or pollen analysis are mainly sensitive to summer temperatures. Here we apply a newly developed leaf cuticle-based proxy to reconstruct growing degree-days (GDD) in a quantitative way and to estimate changes in the timing of spring onset over the last deglaciation. Cuticle analyses of fossil birch leaves preserved in lake sediments from southern Germany reveal extremely low GDD values during the Late Pleniglacial, which are rapidly increasing at the onset of the Bølling/Allerød interstadial. While temperature and GDDs show a simultaneous warming during deglaciation, a GDD decline precedes lowering of summer temperatures during the Older Dryas cooling. Later bud-burst dates support the hypothesis of a shortening the growing season during this cool pulse. 相似文献
13.
Vera Potop Pavel Zahraniček Luboš Türkott Petr Štěpánek Josef Soukup 《Natural Hazards》2014,71(1):1-19
This study has, for the first time, analysed in detail the risk occurrences of the last spring frost, first fall frost and the length of the frost-free period during the growing season of vegetable crops at a high horizontal resolution of 10 km in the Elbe River lowland in the Czech Republic. The daily minimum air temperature from 116 grid points throughout the studied area for the period 1961–2011 was used. The daily values of minimum air temperature ranges of 0 to ?1.1 °C, ?1.2 to ?2.2 °C and below ?2.2 °C were considered to constitute mild, moderate and severe frost intensities, respectively. Firstly, the spatiotemporal variability of the date of the last spring frost, the date of the first fall frost and the length of the frost-free period in the Elbe River lowland is provided. Secondly, the estimation of the probability of a later date in the spring and an earlier date in the fall for various severe frost events and the length of the frost-free period is determined. Third, the changes in the timing of the last and first frosts of the three severities, as well as the length of the frost-free period, are evaluated. From 1961 to 2011, the Elbe River lowland has experienced a decrease in the number of frost days, while the length of the frost-free period between the last spring frost and the first fall frost has increased. The temporal evolution of the frost-free period anomalies displays two distinct periods: a shortening of the frost-free period in the 1960s and an intensified lengthening of the frost-free period since the 1980s. Whereas the latest spring frost has ended on an earlier date across the Elbe River lowland, the first frost date in the fall has generally been delayed to a later date. The dates of the last spring frost have advanced by ?0.21 days per year on average. The fall dates are delayed up to 0.18 days per year, whereas the frost-free period is lengthening by up to 0.39 days per year on average. However, regional frost series suggests that the frost-free period exhibits a large amount of inter-annual variability. In terms of the growth of field vegetables, a late spring frost remains a risk factor, but the degree of risk has decreased. There is a 25 % chance of the occurrence of dangerous spring frosts during the planting of field vegetables after 3rd May, but after 15th May, the risk is only 10 %. 相似文献
14.
Changing growing‐season properties in the northern latitudes are among the most obvious consequences of ongoing global change. Available techniques including satellite monitoring and phenological observations enable the detection of changes over the last few decades to centuries, but the full range of natural variability is still difficult to capture. Here we introduce a new approach to reconstruct growing season properties, by studying imprints of prolonged growing season on epidermal cell growth in Betula nana. A high correlation between cell expansion determined in annually collected B. nana leaves and subfossil leaf fragments collected from recent peat sections in northern Scandinavia, and climatic indices such as budburst date, growing‐season degree‐days and May–September mean temperatures, enable the establishment of a new micro‐phenological proxy for growing season characteristics. The applicability of the epidermal cell undulation index (UI) is tested by comparison with historical instrumental records of growing‐season degree‐days for the last 200 a. The results demonstrate the potential of the new leaf‐morphology‐based technique to reconstruct and quantify past changes in growing degree‐days beyond instrumental data series. Applied to abundant B. nana leaf remains from peat and lake sediments, the UI may enable a reconstruction of growing degree‐days throughout the Holocene and other parts of the late Quaternary. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
15.
Iraq, the land of two rivers, has a history that extends back millennia and is the subject of much archaeological research. However, little environmental research has been carried out, and as such relatively little is known about the interaction between Iraq’s vegetation and climate. This research serves to fill this knowledge gap by investigating the relationship between the Normalized Difference Vegetation Index (NDVI) and two climatic factors (precipitation and air temperature) over the last decade. The precipitation and air temperature datasets are from the Water and Global Change Forcing Data ERA-Interim (WFDEI), and the NDVI dataset was extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS) at 250 m spatial resolution and 16 day temporal resolution. Three different climatic regions in Iraq, Sulaymaniyah, Wasit, and Basrah, were selected for the period of 2001–2015. This is the first study to compare these regions in Iraq, and one of only a few investigating vegetation’s relationship with multiple climatic factors, including precipitation and air temperature, particularly in a semi-arid region. The interannual, intra-annual and seasonal variability for each region is analysed to compare the different responses of vegetation growth to climatic factors. Correlations between NDVI and climatic factors are also included. Plotting annual cycles of NDVI and precipitation reveals a coherent onset, fluctuation (peak and decline), with a time lag of 4 months for Sulaymaniyah and Wasit (while for the Basrah region, high temperatures and a short rainy season was observed). The correlation coefficients between NDVI and precipitation are relatively high, especially in Sulaymaniyah, and the largest positive correlation was (0.8635) with a time lag of 4 months. The phenological transition points range between 3 and 4 month time lag; this corresponds to the duration of maturity of the vegetation. However, when correlated with air temperature, NDVI experiences an inverse relationship, although not as strong as that of NDVI and precipitation; the highest negative correlation was observed in Wasit with a time lag of 2 months (? 0.7562). The results showed that there is a similarity between temporal patterns of NDVI and precipitation. This similarity is stronger than that of NDVI and air temperature, so it can be concluded that NDVI is a sensitive indicator of the inter-annual variability of precipitation and that precipitation constitutes the primary factor in germination while the air temperature acts with a lesser effect. 相似文献
16.
为了解森林退化的原因,利用2000-2015年的MODIS NDVI数据,在分析贵州省植被变化趋势的基础上识别了归一化植被指数（NDVI)显著下降的区域,并在NDVI显著下降区选取面积大于10 km2的森林图斑为兴趣区,分析其内气候变化趋势及对森林NDVI值的影响。研究表明:197个兴趣区主要分布在贵州省西北部的赤水—习水、东北部的梵净山和东南部的非喀斯特区域;区内春、夏季NDVI变化趋势与年NDVI值变化趋势一致,下降速率达到-0.01·yr-1,冬季与其他季节变化趋势相反,呈不显著升高趋势;区内春季和夏季气温升高显著,降水和日照时间无明显变化,整体气候变化呈暖干趋势;夏季温度升高是NDVI降低的主要驱动因素。 相似文献
17.
Assessing vegetation dynamics and their relationships with climatic variability in Heilongjiang province, northeast China 总被引：2，自引：1，他引：1
Wenbin Liu Tijiu Cai Cunyong Ju Guobin Fu Yuefeng Yao Xueqing Cui 《Environmental Earth Sciences》2011,64(8):2013-2024
In this study, the vegetation dynamics in Heilongjiang province and their relationships with climate variability were assessed
using normalized difference vegetation index (NDVI) and meteorological datasets from 1981 to 2003. The conclusions from our
results are as follows: (1) After 1981, vegetation cover, as indicated by the NDVI, exhibited an insignificant increasing
tendency. However, the inter-annual variations of the NDVI showed apparent spatial differentiations. (2) The inter-annual
changes of the NDVI were different from season to season. The spring and autumn NDVI values increased, while the summer and
winter NDVI decreased. (3) The annual NDVI was significantly correlated with precipitation. Thus, as compared to temperature,
precipitation was the dominant climatic factor affecting the vegetation dynamics in Heilongjiang province. (4) The trend in
the NDVI showed a marked homogeneity corresponding to regional and seasonal variations in climate. Additionally, land use
changes also play an important role in influencing the NDVI trends over some regions. All of these findings will enrich our
knowledge of the natural forces that impact the stability of boreal ecosystems and provide a scientific basis for the environmental
management in Heilongjiang province in response to climate change and human activities. 相似文献
18.
基于不同空间尺度、长时间序列的地表反照率产品探究黑河流域2000—2012年的反照率时空变化特征。首先基于角度格网化(AB)算法对黑河流域30 m环境卫星一号HJ-1/CCD大气层顶方向反射率进行了地表反照率估算,作为高空间分辨率的地表反照率产品;选择同种算法计算的1 km空间分辨率的Global LAnd Surface Satellite(GLASS)反照率产品作为低空间分辨率反照率产品。结果表明:1利用AB算法反演的HJ卫星反照率具有较高精度,满足流域尺度反照率时空特征分析的精度要求;2黑河流域地表反照率空间分布差异显著,流域上游植被覆盖区域反照率较低,中下游荒漠地表反照率较高;3流域地表反照率的年内变化与季节性降雪和作物物候周期性变化一致。从季节变化角度,黑河流域反照率月平均值的年变化呈"U"字型,其中,冬季反照率最高,春季和秋季次之,夏季最低。从年际变化角度,黑河下游反照率呈上升趋势,上游和整个流域呈下降趋势。 相似文献