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1.
《The Professional geographer》2013,65(1):140-153
Tropical deforestation is widely believed to directly influence the climate at a number of scales. Yet while much has been written about the tropical forest-climate relationship, there is little empirical evidence showing if and how local and regional climates are modified by deforestation. This study presents the results of an analysis of deforestation and climate change in a rain forest in southern Mexico. Records from 18 climate stations in the Selva Lacandona of Chiapas, Mexico were examined and related to an analysis of deforestation based on Landsat images. The area surrounding some stations has been deforested since the stations were established, while the area surroundings others has remained forested. Strong climatic trends were generally evident at the deforested stations, including decreases in the average daily maximum temperature and temperature range. No precipitation changes were observed. A comparison of the results with microclimatic experiments and modeling studies suggests that the climatic impacts of deforestation are overgeneralized at the local scale. Landscape heterogeneity appears to influence the biophysical mechanisms linking tropical forests and climate, and should be explicitly represented in modeling studies. 相似文献
2.
Based on the citrus temperature, precipitation, sunlight and climate risk degree, the article divides subtropics of China into three types: the low risk region, the moderate risk region and the high risk region. The citrus temperature risk increases with increasing latitude (except for the western mountainous area of subtropics of China). The citrus precipitation risk in the central part of subtropics of China is higher than that in the northern and western parts. The distributions of citrus sunlight risk are not consistent to those of the citrus precipitation risk. The citrus climate risk is mainly influenced by temperature. There is latitudinal zonal law for the distribution of the climate risk, that is, the climate risk increases with increasing latitude. At the same time the climate risk in mountainous area is high and that in eastern plain area is low. There are differences in the temporal and spatial changes of the citrus climate. In recent 46 years, the citrus climate risk presents a gradual increasing trend in subtropics of China, especially it has been increasing fast since the 1980s. Because of the global warming, the low risk region in the eastern and southern parts has a gradual decreasing trend, however, the high risk region in the northern and western parts has an increasing trend and the high risk region has been extending eastward and southward. The article analyses the distribution of the citrus climate risk degree of reduction rates of >10%, >20% and >30% in subtropics of China, and studies their changes in different time periods. Results show that the risk is increasing from southeast to northwest. 相似文献
3.
Based on the citrus temperature, precipitation, sunlight and climate risk degree, the article divides subtropics of China
into three types: the low risk region, the moderate risk region and the high risk region. The citrus temperature risk increases
with increasing latitude (except for the western mountainous area of subtropics of China). The citrus precipitation risk in
the central part of subtropics of China is higher than that in the northern and western parts. The distributions of citrus
sunlight risk are not consistent to those of the citrus precipitation risk. The citrus climate risk is mainly influenced by
temperature. There is latitudinal zonal law for the distribution of the climate risk, that is, the climate risk increases
with increasing latitude. At the same time the climate risk in mountainous area is high and that in eastern plain area is
low. There are differences in the temporal and spatial changes of the citrus climate. In recent 46 years, the citrus climate
risk presents a gradual increasing trend in subtropics of China, especially it has been increasing fast since the 1980s. Because
of the global warming, the low risk region in the eastern and southern parts has a gradual decreasing trend, however, the
high risk region in the northern and western parts has an increasing trend and the high risk region has been extending eastward
and southward. The article analyses the distribution of the citrus climate risk degree of reduction rates of >10%, >20% and
>30% in subtropics of China, and studies their changes in different time periods. Results show that the risk is increasing
from southeast to northwest. 相似文献
4.
'The gloomy forebodings of this dread disease', climate, famine and sleeping sickness in East Africa
GEORGINA H ENDFIELD DAVID B RYVES† KEELY MILLS† LEA BERRANG-FORD‡ 《The Geographical journal》2009,175(3):181-195
Identifying the nature of the association between climate, environmental, socio-economic and political context and disease remains a major challenge, yet a better comprehension of the linkages is imperative if predictive models to guide public health responses are to be devised. Our understanding of the relationships could be improved through investigations of historical epidemics. In this paper we draw on a range of published and unpublished documents to explore the complex relationship between climate, environmental change and epidemic disease (re)emergence in East Africa, and Uganda in particular. This is a region which has experienced climate variability at a range of temporal and spatial scales, but which also has a long history of episodic epidemic disease. We focus on the late nineteenth and early twentieth centuries – a time of social, economic and political reordering in East Africa associated with European colonial intervention, but also a period which witnessed a variety of climatic, ecological and disease events. It will be argued that these developments coalesced, creating a set of spatially distinctive social and environmental conditions which fostered the emergence and prolongation of one of the most deadly episodes of disease in East African history, the sleeping sickness epidemic of c.1900–20. 相似文献
5.
准噶尔盆地的气候变化与荒漠环境研究 总被引：44，自引：23，他引：21
通过对北疆及准噶尔盆地的气候变化与荒漠环境效应研究认为,该区一是受气候变化的影响,其次是受地形和人类活动的影响。在气候变化和环境效应研究中,该地区有着不可替代的区域特征和学科意义。尤其是该区域受西风环流控制和受太平洋季风的影响较少,因此具有季风气候和地中海气候的双重性。因此,该研究区荒漠环境的正逆发展过程不仅受降水和温度的重大影响,而且季节性积雪和高山雪冰融水为荒漠植物的萌发与生长提供了有效的水资源。但是,该地区的生态环境十分脆弱,人类的过度开发和扰动对其的影响也非常严重。所以,加强气候变化与环境效应的相互影响研究,保护干旱生态的平衡发展,再造秀美山川,是该地区今后研究的重要任务和发展方向。 相似文献
6.
Antony R. Orme 《自然地理学》2013,34(2):138-161
Deformed marine terraces provide excellent measures of Quaternary tectonism along 400 km of the Pacific coast of Baja California between Ensenada and Punta Blanca. The nature and magnitude of deformation are well expressed by the present elevation of the marine limit, of Upper Pliocene or Lower Pleistocene age, which has been upwarped to 345m, 357m, and at least 195m in three separate localities, while occurring at lower levels elsewhere. Multiple terraces are found below this marine limit where appreciable uplift has occurred. Where relative subsidence has prevailed, fewer broader terraces or thick alluvial and eolian deposits occur. Terraces are further dislocated by NW-SE strike-slip faulting and by normal faults that trend NE-SW across the coast. Folding and faulting are less significant on the younger terraces than on the older features, and negligible for the Sangamonian terrace, except close to major faults. Crustal movements revealed by these terraces, and by similar features in southern California, Baja California Sur, and around the Gulf of California, are interpreted in terms of plate tectonics. Over the past 5 million years, the Peninsular Ranges have been carried northwestwards away from mainland Mexico, at an average rate of 6cm/yr, on the dis located limb of a spreading sea floor associated with the East Pacific Rise now found beneath the Gulf of California. The Pacific coast of the Peninsular Ranges comprises several discrete crustal slivers which, on the evidence of the marine terraces, have been warped and dislocated in response to tec tonic forces associated with rafting and subsequent crowding against transverse structures to the north. Uplift rates range as high as 1.0m/1000 yrs locally but are generally less, and are much less than rates found in the Transverse Ranges farther north. As in the latter province, basins typified by net sub sidence during Quaternary time are also found. 相似文献
7.
新疆博州地区近46年来的气候变化特征 总被引：23，自引：4，他引：23
根据新疆博尔塔拉蒙古自治州(简称博州,下同)四个气象代表站点的气温及降水资料,利用线性趋势函数及t检验法分析了该地区近46年的气候变化。结果表明,博州年平均气温、平均最高气温、平均最低气温均呈上升趋势,而且平均最低气温上升的幅度远大于平均最高气温的上升幅度。年平均气温及年平均最低气温约在20世纪80年代中期出现了显著的均值突变,而年平均最高气温在80年代末出现突变;除春、夏季平均最高气温无明显变化趋势外,其它各季平均气温、平均最高气温、平均最低气温均呈上升趋势,其中均以冬季增幅最大,秋季次之;80年代冬夜升温最强劲,90年代则明显减弱;夏季的平均气温与平均最低气温均在70年代中期出现突变,比其它任何突变时间都早;暖温年多发生在80年代后,冷温年多发生在20世纪60年代、70年代。年降水量略呈上升趋势,少雨年多在60年代、70年代,多雨年多在近20年,除春季外,其余各季降水略有上升趋势。 相似文献
8.
新疆伊犁河流域气候变化(英文) 总被引：3，自引：0，他引：3
In this paper, the monthly precipitation and temperature data collected at 7 stations in the Ili River Basin from 1961 to
2007 were analyzed by means of simple regression analysis, running mean, db6 wavelet function and Mann-Kendall test. This
study revealed the characteristics of climate change and abrupt change points of precipitation and temperature during different
time scales in the Ili River Basin within the past 50 years. The results showed that the precipitation increased from the
mid-1980s until 2000 and has continued to increase at a smaller magnitude since 2000. Over the studied period, the precipitation
increased significantly during the summer and winter months. The temperature increased greatly in the late 1980s, and has
continued to show an increasing trend from the year 2000 to present. The temperature increases were most significant during
the summer, autumn and winter months. In terms of different geographies, the temperature increase was significant during the
winter in the plains and hilly regions; the increase was also significant during autumn in the intermontane basins. The climate
change trends in the Ili River Basin were consistent with the changing trends of the North Atlantic Oscillation and the plateau
monsoon. 相似文献
9.
东疆北部全新世气候不稳定性的湖泊沉积记录 总被引：3，自引：2，他引：1
对新疆东疆北部巴里坤湖2.5 m深的沉积剖面进行了年代学、沉积物粒度、TOC、磁化率和CaCO3含量分析,对比研究确定了巴里坤湖的碳库年龄约为750 a,据此建立了研究剖面的年代序列。研究表明,各气候代用指标序列揭示了巴里坤湖地区全新世期间存在多次干湿气候波动,并伴随着一系列突发气候事件,其中有6次事件可以与全新世北大西洋浮冰碎屑事件及GISP2冰芯氧同位素记录进行良好对比,且呈现出显著约1.6 ka的变化周期,表明高纬度北大西洋地区的气候变化可能通过对西风环流的影响与中国西北干旱区的气候变化密切相关。谱分析揭示出研究区气候变化还具有显著的200 a,133 a,108 a和77 a周期,可能与太阳活动周期有关。6300—5200 cal a BP和4300—3500 cal a BP期间巴里坤湖地区气候较为干旱,结合广泛的区域对比认为,中全新世干旱事件具有普遍性。 相似文献
10.
SUN Huilan CHEN Yaning LI Weihong LI Feng CHEN Yapeng HAO Xingming YANG Yuhui 《地理学报》2010,20(5):652-666
In this paper, the monthly precipitation and temperature data collected at 7 stations in the Ili River Basin from 1961 to 2007 were analyzed by means of simple regression analysis, running mean, db6 wavelet function and Mann-Kendall test. This study revealed the characteristics of climate change and abrupt change points of precipitation and temperature during different time scales in the Ili River Basin within the past 50 years. The results showed that the precipitation increased from the mid-1980s until 2000 and has continued to increase at a smaller magnitude since 2000. Over the studied period, the precipitation increased significantly during the summer and winter months. The temperature increased greatly in the late 1980s, and has continued to show an increasing trend from the year 2000 to present. The temperature increases were most significant during the summer, autumn and winter months. In terms of different geographies, the temperature increase was significant during the winter in the plains and hilly regions; the increase was also significant during autumn in the intermontane basins. The climate change trends in the Ili River Basin were consistent with the changing trends of the North Atlantic Oscillation and the plateau monsoon. 相似文献
11.
在全球气温日趋升高和极端降水增加的气候背景下，近年来中国干旱变化特征异常突出，新形势下需进一步深入认识干旱灾害影响机制。利用1960—2014年中国527个气象站逐日气温和降水量数据，选用改进的综合气象干旱指数（MCI）作为监测指标，详细分析了中国干旱强度、频次和持续时间变化特征及其南北差异性。结果表明：气候变暖背景下，中国干旱范围扩大、程度加剧、频次增加；干旱发生的范围发生了明显的转移，北方干旱加剧的同时，南方干旱明显加重，尤其是大旱范围明显增加。中国干旱范围主要在黄河流域以南和长江以北地区。干旱频次北方高于南方，东部高于西部，长江流域以北干旱频次较高。中国干旱持续时间较长，而且四季都有可能发生干旱。干旱不仅发生在干旱区和半干旱区，湿润和半湿润区域也常有干旱发生。不同年代、不同区域干旱发生的程度、持续时间和频次有一定的差异。中国20世纪90年代中后期至21世纪初期干旱范围最广、持续时间最长，造成的损失最严重。中国干旱强度、频次和持续时间南北差异性显著。气候变暖后，中国干旱强度加重、范围扩大、频次增加和持续时间增加明显。 相似文献
12.
Rainfall variability,rainfed agriculture and degree of human marginality in North Guanajuato,Mexico 
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下载免费PDF全文 Rebeca Granados Jesus Soria Moises Cortina 《Singapore journal of tropical geography》2017,38(2):153-166
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. 相似文献
13.
Assessing Climate Change in the Contiguous United States Using a Modified Thornthwaite Climate Classification Scheme 总被引：1，自引：0，他引：1
Andrew Grundstein 《The Professional geographer》2013,65(3):398-412
Climate change across the contiguous United States is investigated using a modified version of Thornthwaite's climate classification scheme. This approach allows both moisture and thermal conditions to be examined simultaneously for a better assessment of multivariate climate change. Changes in area of different climate types over time is determined using the climate year approach and the spatial nature of climate change is examined by computing climate types based on averages from three thirty-year periods over the twentieth century. Over the study period from 1895 to 2005, statistically significant changes in areal coverage of different climate types have occurred. In the eastern half of the country, climate divisions have become wetter and changed to moister climate categories. The most prominent change has occurred in the Deep South, where the climate has changed to both a lower thermal category and a wetter moisture category. Much of the country has experienced positive temperature trends, but only climate divisions in the Southwest and Upper Midwest show changes to higher thermal categories. 相似文献
14.
民勤绿洲-荒漠过渡带典型固沙植物生殖物候对气候变化的响应 总被引：1，自引：0，他引：1
通过对民勤绿洲-荒漠过渡带典型固沙植物多枝柽柳(Tamarix ramosissima)、梭梭(Haloxylon ammodendron)、白刺(Nitraria tangutorum)1974-2009年开花及结实物候的观测,结合同步观测的气象资料,分析了3种植物生殖物候特征对气候变化的响应规律。结果表明:(1)研究区年平均气温、年平均空气相对湿度呈增加趋势; 年降雨量波动,变幅不大; 20世纪90年代以来蒸发量呈显著下降趋势。(2)3种植物始花期提前,花期延长; 3种植物结实始期先延迟后缩短,结实期延长; (3)3种植物生殖物候与年降雨量、气温、空气相对湿度及前期累计降雨量、累计平均气温、累计空气相对湿度之间的相关性不一致; (4)3种植物始花期与前期累计降雨量、累计平均气温、累计空气相对湿度的相关性总体上表现为大于年降雨量、年均气温、年均空气相对湿度的相关性; 除空气平均相对湿度对结实始期影响大于前期累计降雨量、累计平均气温和累计空气相对湿度外,其他与开花物候相似,表明植物开花物候和结实物候与前期气象因子有着密切的关系,尤其是物候发生前期累计气象指标。 相似文献
15.
哀牢山北段地区气候特征及变化趋势 总被引：2，自引：0，他引：2
以哀牢山北段地区不同位置的景东（西侧盆地）、徐家坝（山顶）和楚雄（东侧盆地）为研究对象,利用三地1980～2005年同期气候观测资料,通过统计分析,探讨了哀牢山东、西侧盆地及山顶气温和降雨特征及长期变化趋势。结果表明：哀牢山北段地区最热月均出现在6月;最冷月,西侧盆地和山顶为1月,东侧盆地最冷月为12月;降雨的季节差异十分显著,雨季降雨量占全年的85％以上,以7月降雨量最多。从气候的长期变化趋势来看,年、季和月平均气温均呈现显著的升高趋势,气温的显著升高主要发生在干季,增温率为干季〉年〉雨季。最冷月均温增温率最大,最热月均温没有显著增加,气温年较差呈减小趋势。研究表明,哀牢山北段地区山顶及两侧盆地均呈现显著的变暖趋势,与植物生存直接相关的∑t≥0℃有效积温和∑t≥10℃活动积温也显著增加。气温的变化具有显著的空间差异,增温速率为东侧盆地〉山顶〉西侧盆地。山地迎风坡面（西坡）气温垂直递减率显著减小,背风坡面（东坡）气温垂直递减率整体呈增大趋势。降雨整体呈增加趋势,不同季节间降雨的变化差异显著,年降雨量的增加主要由于雨季降雨的增加,干季降雨呈微弱上升或下降趋势,降雨的增加率为东侧盆地〉山顶〉西侧盆地。哀牢山北段地区干季的干热气候特征进一步加剧,这种变化趋势在山地的背风坡面（东坡）表现得更加剧烈。 相似文献
16.
兴安岭多年冻土退化特征 总被引：7，自引：0，他引：7
受气候变暖和人为活动的共同影响,过去数十年来兴安岭山区的多年冻土退化显著.冻土退化南部快于北部、城镇快于田野、农田快于林区、采伐过林区快于原始林区.在局部小范围内,冻土退化顺序为先高后低、先山上后谷地(或盆地中心)、先阳坡后阴坡.冻土退化程序从农田(或裸地)→草地→灌丛→林地→沼泽湿地,依次冻土退化由快到慢.纬度和高度地带性控制冻土退化特征,但局地因素亦对其产生重要影响,造成小范围内冻土特征的突变.人为活动已经、正在并将对兴安岭冻土退化和寒区生态环境产生重要影响. 相似文献
17.
作物气候风险研究:以河南省棉花为例 总被引：1，自引：0，他引：1
1 Introduction In the past 100 years the global temperature rose sharply due to the increase of greenhouse gas emissions into the atmosphere. The mean ground temperature rose by 0.5–0.6°C in the 20th century and 0.3–0.4°C in the last 20 years of the c… 相似文献
18.
Heather L. Purdie Martin S. Brook Ian C. Fuller John Appleby 《New Zealand geographer》2008,64(1):5-19
Abstract: Seasonal variations in ablation and surface velocity were investigated on the lower Fox Glacier. Variations occur between summer and winter ablation, with surface velocity also showing marked seasonality. Recent advance has resulted in the glacier gaining around 200 m length since late 2004. Longer term, Fox Glacier appears linked to the Southern Oscillation Index, with positive glacier mass balances associated with negative Southern Oscillation Index (El Niño). An estimated glacier response time of approximately 9–14 years suggests the current terminus advance was linked to mass gains in the mid-1990s. Recent collapses at the terminal face continue to prove a hazard at this busy tourist destination. 相似文献
19.
艾比湖流域沙尘气候变化趋势及其突变研究 总被引：25，自引：8，他引：17
通过艾比湖流域5个气象站建站~2001年的观测资料,对艾比湖流域沙尘气候的变化趋势进行了分析。结果表明,气候发生了明显的变化,主要表现在气温升高,降水增多,但分布不均,沙尘暴、扬沙和大风日数稳定减少,但浮尘日数显著上升,风速分布发生了变化,大风日数的迅速减少还引起蒸发能力的减弱。艾比湖干枯的湖底盐漠面积与该流域沙尘总日数之间存在密切关系,艾比湖水域的伸缩而引发的荒漠化环境变化是造成该流域沙尘天气的主要因素。对艾比湖流域沙尘气候的突变检验结果表明,大风、沙尘暴、扬沙日数的减少和浮尘日数的上升是一种突变现象,这种突变与整个西北气候的变化和艾比湖流域沙漠化条件的变化存在一定的关系。 相似文献
20.
RELATION BETWEEN VEGETATION CHANGES, CLIMATE VARIABLES AND LAND-USE POLICY IN SHAANXI PROVINCE, CHINA 总被引：1，自引：0，他引：1
MADELENE OSTWALD ELISABETH SIMELTON DELIANG CHEN ANLIN LIU 《Geografiska Annaler: Series A, Physical Geography》2007,89(4):223-236
Shaanxi Province in China has been exposed to climate variability and dramatic land‐use policies. The aim here is to examine vegetation changes in this area on a regional scale from 2000 to 2004 in relation to land‐use changes and climate traits. The data in this assessment include remote sensing information from moderate‐resolution imaging spectro‐radiometer normalized difference vegetation index from 2000 to 2004, and climate data (precipitation and temperature) from 1956 to 2000. The results show an increase in vegetation production from 2000 to 2004, particularly in the north, which cannot be explained solely by climate impacts. Since the vegetation in the north is more dependent on climate variation than the other parts of Shaanxi due to more serious water limitation, the results suggest that the large‐scale land‐use policy implemented over the last decade, with a focus on northern Shaanxi, is possibly having an impact on the overall vegetation. 相似文献