未来气候变化对云南柠檬气候适宜性的影响     

范丹华  杨弘伟  邵晨扬  王鹏云  朱勇 《气象科技》2021,49(6):968-974

气候变化影响柠檬生长、产量和品质，本文利用云南省125个国家气象站1981—2018年,月平均气温、月平均降水量、月日照时数，进行基准年代下云南柠檬气候适宜性分区；采用RCP2.6、RCP4.5、RCP8.5气候情景模式，研究2021—2030年、2031—2040年、2041—2050年云南柠檬气候适宜区的变化，探讨未来气候变化背景下，云南柠檬气候适宜性变化，以期对柠檬产业布局、规划、引种提供科学的指导。结果表明：21世纪中叶，RCP2.6情景下柠檬最适宜种植区增加了3成左右，RCP4.5情景下柠檬最适宜种植区增加了5成左右，RCP8.5情景下柠檬最适宜种植区增加了9成左右。但由于受降水因子的限制，中度适宜区到2041—2050年开始缩减，总的可适宜种植区（高度适宜区+中度适宜区）基本趋于稳定，这将给柠檬在云南的种植发展提供广阔空间。  相似文献   

基于土地适宜性评价与元胞自动机模型的城市开发边界划定方法     

李焰  梁美丽 《北京测绘》2021,35(2):222-229

城市开发边界的划定可以在一定程度上引导城市空间的良性扩张。为了研究边界划定的方法,以我国某港口城市作为研究区域,在空间增长模拟的方向进行探索。研究中借助土地适宜性评价和元胞自动机边界工具,构建既符合生态资源环境要求又符合城市发展需要的边界划定,同时,为了实现城市用地健康和动态管控举措,提出了建立健全土地用地管理机制的要求。  相似文献   

Présence d'une mangrove à Avicennia au Miocène moyen dans la région de Digne (Alpes-de-Haute-Provence,France) : implications stratigraphiques et paléoclimatiques     

Jean-Jacques Châteauneuf  Hugues Bauer  Isabelle Cojan 《Comptes Rendus Geoscience》2006,338(3):197-205

Avicennia pollen grains have been discovered in marine facies from the Middle Miocene deltaic series of Châteauredon (southeastern France). Based on the local stratigraphy, an age between 15.8 and 16.5 Ma is proposed for these grains. The age and the transgressive context of the Avicennia bearing-levels are in agreement with the maximum extension of the mangrove known in the western Mediterranean during interval N8–NN4 pro parte, in relation with the Langhian highstand. This mangrove occurrence at 42°N latitude during Middle Miocene is a more northern witness of the mangrove sites known in Languedoc and Provence areas. It also implies a lower climatic gradient than today. To cite this article: J.-J. Châteauneuf et al., C. R. Geoscience 338 (2006).  相似文献   

Relations between climatic variability and hydrologic time series from four alluvial basins across the southwestern United States   总被引：1，自引：3，他引：1  

R. T. Hanson  M. D. Dettinger  M. W. Newhouse 《Hydrogeology Journal》2006,14(7):1122-1146

Hydrologic time series of groundwater levels, streamflow, precipitation, and tree-ring indices from four alluvial basins in the southwestern United States were spectrally analyzed, and then frequency components were reconstructed to isolate variability due to climatic variations on four time scales. Reconstructed components (RCs), from each time series, were compared to climatic indices like the Pacific Decadal Oscillation (PDO), North American Monsoon (NAM), and El Niño-Southern Oscillation (ENSO), to reveal that as much as 80% of RC variation can be correlated with climate variations on corresponding time scales. In most cases, the hydrologic RCs lag behind the climate indices by 1–36 months. In all four basins, PDO-like components were the largest contributors to cyclic hydrologic variability. Generally, California time series have more variation associated with PDO and ENSO than the Arizona series, and Arizona basins have more variation associated with NAM. ENSO cycles were present in all four basins but were the largest relative contributors in southeastern Arizona. Groundwater levels show a wide range of climate responses that can be correlated from well to well in the various basins, with climate responses found in unconfined and confined aquifers from pumping centers to mountain fronts.  相似文献   

Impacts of Holocene climatic variations on alluvial fan activity below snowpatches in subarctic Québec     

Violaine Lafortune  Louise Filion  Bernard Htu 《Geomorphology》2006,76(3-4):375-391

In the Lake Guillaume-Delisle area of subarctic Québec, storm-generated alluvial fans have been active sporadically throughout the Holocene. In this study, we propose that the persistence of late-lying snowpatches in fan catchments during Holocene cold episodes promoted alluvial fan activity by lowering the precipitation threshold required to trigger a torrential event. This hypothesis was tested by characterizing the depositional processes responsible for alluvial fan formation below snowpatches, and by reconstructing the Holocene alluvial fan activity. Stratigraphic and sedimentary analyses conducted on seven alluvial fans revealed that they were deposited by torrential activity leading to waterlaid, transient, or hyperconcentrated deposition. The chronology of the storm-generated alluvial fans — based on 22 radiocarbon dates — indicates that torrential activity was enhanced during the cooler Late Holocene (i.e., after ca. 3500 cal. yr BP). Snowier winters and cooler summers were beneficial to nival activity, allowing the persistence of larger snowpatches throughout the summer and fall seasons. Rainfall-induced thaw of such snowpatches during rainstorm events is inferred to have contributed to alluvial fan activity by increasing water availability. Three peaks of alluvial activity occurred during the Late Holocene (2950–2750, 1900–1400, and 800–300 cal. yr BP) and are indicative of increased storminess resulting in higher fan activity. Increased fan activity during cooler episodes was concurrent with increased runoff activity in the immediate pronival area. This stresses the importance of nivation below snowpatches and pinpoints the role of nivation in enhancing geomorphological activity during period of cooler and more humid climate in subarctic environments.  相似文献   

On global forces of nature driving the Earth’s climate. Are humans involved?     

L. F. Khilyuk  G. V. Chilingar 《Environmental Geology》2006,50(6):899-910

The authors identify and describe the following global forces of nature driving the Earth’s climate: (1) solar radiation as a dominant external energy supplier to the Earth, (2) outgassing as a major supplier of gases to the World Ocean and the atmosphere, and, possibly, (3) microbial activities generating and consuming atmospheric gases at the interface of lithosphere and atmosphere. The writers provide quantitative estimates of the scope and extent of their corresponding effects on the Earth’s climate. Quantitative comparison of the scope and extent of the forces of nature and anthropogenic influences on the Earth’s climate is especially important at the time of broad-scale public debates on current global warming. The writers show that the human-induced climatic changes are negligible.  相似文献   

时间序列转折突变点检测的线性函数方法   总被引：6，自引：2，他引：6  

曹杰  陶云  田永丽 《高原气象》2002,21(5):518-521

根据转折突变的定义，在引入线性半截多项式的前提下，提出检测时间序列转折突变点的一种新方法。此方法不仅能找出时间序列中存在的多个转折突变点，而且使得检测到的突变点通过统计显著性检验。应用此方法对北半球1851—1990年年平均气温距平及其11年滑动平均序列，1901—1999年昆明5月降水及其11年滑动平均的降水序列分别进行了检测。发现北半球年平均气温距平在1879、1889、1939和1973年附近出现了年际转折突变，在1878、1888和1941年以及1972年出现了年代际尺度的转折突变；昆明5月雨量不存在年际转折突变点，但昆明5月雨量在1918、1966以及1978年附近出现了年代际尺度转折突变。  相似文献   

青藏高原冬季平均温度、湿度气候特征的REOF分析   总被引：14，自引：2，他引：14       下载免费PDF全文

牛涛  陈隆勋  王文 《应用气象学报》2002,13(5):560-570

通过对青藏高原123个测站, 1961~1998年冬季 (12月至翌年2月) 平均温度、相对湿度资料做气候特征分析, 得到32°~33°N附近地区可能是高原南北温湿变化的分水岭, 以北主要受干冷空气影响, 以南主要受暖湿空气影响。用方差极大正交旋转EOF (即REOF) 方法对以上资料进行分析, 可以将青藏高原温度、相对湿度进行分型、分区, 并对各区的温度、相对湿度特征进行分析。结果表明, 近40年来, 各区的温度总趋势是在波动中逐步升高的。增温时段主要出现在1978~1981年及1983年至今。1983年开始的增温, 是近40年来最强的一次, 增温幅度大且持续时间长, 但从90年代开始增温幅度及范围出现波动。从温度线性倾向来看, 东部高原增温幅度从南到北存在“大—小—大”的现象。高原大部分地区湿度变化总趋势是在波动中逐步增湿的, 但高原北界以变干为主。从80年代后期至今高原进入显著增湿阶段, 但从90年代中后期开始增湿幅度及范围出现波动。从湿度线性倾向来看东部高原增湿幅度从南到北存在逐步减小现象, 甚至祁连山地区出现变干现象。  相似文献   

同位素地质学定年方法评述   总被引：16，自引：1，他引：16  

赵玉灵  杨金中等 《地质与勘探》2002,38(2):63-67

详细分析了当前同纱年代学的常用定年方法，如K-Ar法，U-Pb法，Rb-Sr法和Sm-Nd法等的适用性和局限性。讨论了地质事件定年过程中存在的一些问题，提出了准确定年的注意事项。  相似文献   

晚更新世以来青海北部的人类活动与湖泊演变          下载免费PDF全文

周笃珺  马海州  P.J.Brantingham  谭红兵 《盐湖研究》2003,11(2):8-13

作为高海拔生态环境的青海北部是青藏高原的重要组成部分。晚更新世晚期以来 ,青海北部气候环境一直处于冷暖、干湿波动过程之中 ,湖泊水域也发生了相应的扩张和收缩 ,成为高原人类迁移和发展的自然背景。约 3 0kaB .P .,在晚期智人出现和迁徙的关键时期 ,青海北部开始有了最早的人类活动 ;更新世末—全新世初 ,气候转暖 ,古人类再次来到青海北部 ;进入全新世中期 ,气候暖湿 ,湖水位回升 ,细石器技术变得十分普通 ,青海北部的人类活动渐趋频繁。  相似文献