新疆NDVI时空特征及气候变化影响研究
作者简介:慈 晖(1989- ),女,博士,讲师,研究方向为区域水文循环与水资源演变。E-mail:cathyyyci@163.com
收稿日期: 2016-10-08
要求修回日期: 2017-01-20
网络出版日期: 2017-05-20
基金资助
国家杰出青年科学基金项目(51425903)
江苏第二师范学院博士专项(JSNU2015BZ01)
安徽省自然科学基金项目(1508085MD65)
Spatio-temporal Patterns of NDVI Variations and Possible Relations with Climate Changes in Xinjiang Province
Received date: 2016-10-08
Request revised date: 2017-01-20
Online published: 2017-05-20
Copyright
基于新疆50个气象测站2003-2010年逐日降水、气温资料,结合逐月归一化植被覆盖影像资料,利用趋势分析、R/S分析、模糊C均值聚类、图像处理等方法,系统分析了全疆NDVI时空变化特征及其可持续性,并探究NDVI与气候因子(气温、降水)之间的相关性。研究表明:植被覆盖及气象因子年际间差异不大,呈现出整体稳定的态势,但年内变化明显。北疆/天山北坡水热条件优良、植被长势最好,且植被长势对气候因子的滞后效应并不明显且滞后时间短。天山南坡/天山东段次之,而南疆植被覆盖程度最差,南疆/天山南坡植被长势对气候因子(降水、气温)存在明显的滞后效应,植被生长受气温、降水限制性更大,且气温作为主要因子,对天山南坡植被生长的限制作用表现得更为突出。总体上,新疆植被覆盖呈持续性变化,现有植被覆盖情况基本保持不变,但呈退化趋势的面积大于得到改善的面积,在一定程度上与人类活动有很大关系,探查植被长势的变化趋势并及时做出相应调整,不仅能为新疆地区的植被保护以及植被恢复工作提供一定的科学依据,更能够为合理有效地安排农作物生产提供重要的理论指导。
慈晖 , 张强 . 新疆NDVI时空特征及气候变化影响研究[J]. 地球信息科学学报, 2017 , 19(5) : 662 -671 . DOI: 10.3724/SP.J.1047.2017.00662
Spatio-temporal patterns of NDVI and possible relations between NDVI and climate factors in Xinjiang Province have been analyzed based on daily precipitation and temperature data covering the period of 2003-2010 from 50 meteorological stations. Results show that inter-annual variations of NDVI and climate factors are not evident and apparent annual changes are well identified. Abundant precipitation and high temperature was observed in summer and autumn with good coverage of vegetation. However, the adverse conditions can be found in winter and spring. The northern Xinjiang as well as the north slope of the Tianshan Mountains are dominated by abundant precipitation and flourishing vegetation. The south slope of Tianshan Mountains and the eastern Xinjiang take second place. The southern Xinjiang, however, is characterized by scarce precipitation, high temperature and poor vegetation coverage. The vegetation condition in northern Xinjiang and the north slope of Tianshan Mountains has no obvious time-lag response to climate factors. Nevertheless, it has obvious time-lag response to climate factors and the growth of vegetation is restricted by climate factors in southern Xinjiang and the south slope of Tianshan Mountains. As the main factor, restriction of temperature is more prominent. Overall, the vegetation varied continuously in Xinjiang and the area of improvement tendency is less than those of degradation tendency. To some extent, human activity has a great influence on the vegetation condition. Exploration of vegetation changes and carrying out of timely adjustments, not only can offer a scientific basis for vegetation protection and restoration, but also can provide important theoretical guidance for crop production effectively.
Fig. 1 Locations of study region,meteorological stations and different land use types in Xinjiang图1 研究区气象测站及新疆主要土地利用类型分布 |
Fig. 2 Fuzzy C clustering and geographic partition FCM-based regionalization of meteorological stations and five sub-regions图2 模糊C聚类及地理分区 |
Fig. 3 Spatial and temporal distribution of the annual and seasonal average NDVI图3 空间及时间尺度年及四季平均NDVI |
Tab. 1 Statistics of tendency of annual average NDVI表1 年均NDVI变化趋势 |
NDVI变化趋势 | 等级 | 面积(km2) | 占全疆比例/% |
---|---|---|---|
slope<-0.009 | 严重退化 | 42 016 | 0.87 |
-0.009≤slope <-0.0045 | 中度退化 | 178 960 | 3.72 |
-0.0045≤slope<-0.001 | 轻微退化 | 777 316 | 16.15 |
-0.001≤slope<0.001 | 基本不变 | 2 959 714 | 61.50 |
0.001≤slope<0.0045 | 轻微改善 | 599 140 | 12.45 |
0.0045≤slope<0.009 | 中度改善 | 167 875 | 3.49 |
slope≥0.009 | 明显改善 | 87 564 | 1.82 |
Fig. 4 Tendency, sustainability and comprehensive characteristics of NDVI variation图4 NDVI变化趋势及可持续性综合特征 |
Tab. 2 Statistics of sustainability of annual average NDVI表2 NDVI变化持续性统计 |
H指数 | 可持续性 | 面积/km2 | 占全疆比例/% | H指数 | 反持续性 | 面积/km2 | 占全疆比例/% |
---|---|---|---|---|---|---|---|
H>0.65 | 强 | 1 887 794 | 39.23 | H≤0.35 | 强 | 104 068 | 2.16 |
0.5<H<0.65 | 弱 | 2 028 254 | 42.14 | 0.35<H<0.5 | 弱 | 792 463 | 16.47 |
Tab. 3 Statistics of comprehensive analysis of annual average NDVI表3 NDVI变化综合特征 |
综合特征 | 面积/km2 | 占全疆比例/% | 综合特征 | 面积/km2 | 占全疆比例/% |
---|---|---|---|---|---|
退化&强反持续 | 35 466 | 0.74 | 不变&弱可持续 | 1 322 444 | 27.48 |
退化&弱反持续 | 184 430 | 3.83 | 不变&强可持续 | 1 134 681 | 23.58 |
退化&弱可持续 | 374 158 | 7.77 | 改善&强反持续 | 22 370 | 0.46 |
退化&强可持续 | 404 238 | 8.40 | 改善&弱反持续 | 151 679 | 3.15 |
不变&强反持续 | 46 232 | 0.96 | 改善&弱可持续 | 331 655 | 6.89 |
不变&弱反持续 | 456 354 | 9.48 | 改善&强可持续 | 348 875 | 7.25 |
Fig. 5 Temporal distribution of monthly average values of precipitation, temperature and NDVI图5 5个分区多年月均降水量、均温及NDVI变化 |
Fig. 6 Relationship of NDVI with precipitation and temperature图6 NDVI与气候因子相关性 |
The authors have declared that no competing interests exist.
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