黄土高原植被变化及其对极端气候的响应
韩丹丹
Subtype硕士
2020-05
Degree Grantor中国科学院大学
Place of Conferral中国科学院教育部水土保持与生态环境研究中心
Degree Name工程硕士
Keyword黄土高原,植被变化,极端气候指数,ndvi,时空变化
Abstract

植被是连接土壤、水和大气的纽带,在全球变化中有着重要的作用。随着全球变暖,极端气候频发,强度增强,对植被的生长产生了重要的影响,导致植被覆盖状况的剧变。本文基于1982—1999年黄土高原GIMMS NDVI数据和2000-2017MODIS NDVI数据与87个气象站日降雨、日最高温和日最低温数等气象数据,采用趋势分析、相关分析等方法,研究黄土高原植被覆盖度时空变化及其对极端气候的响应。得到以下研究结果:

1)黄土高原NDVI呈显著增加趋势。1982-2017年黄土高原NDVI以每年0.37%的幅度增加(p0.01)。黄土高原各月植被NDVI季节变化明显,呈单峰模式变化,从4月开始生长,8月达到峰值,在8月后,NDVI值整体呈下降趋势。空间上,该地区植被呈西北低东南高的分布格局,与1982年相比,2017年黄土高原西北地区植被覆盖状况明显改善,且分布在高值区的东南部植被覆盖状况也呈增长趋势。

2)极端气候指数变化中,极端气温指数变化趋势显著,而极端降水指数显著性检验不明显。极端气温指数变化趋势较为一致,即表征极端高温事件的指数(SU25TMAXmeanTMINmeanTN90pTXxTNn)呈极显著的增加趋势,表征极低温事件的指数(FD0TN10p)均呈现下降的趋势,极端降水指数未发生明显变化。极端降水指数(RX1dayRX5dayR50 mmCDD)空间分布较为一致,均呈由西北部向东南部递增的空间分布格局。黄土高原中部和东南部降水更多,主要分布在子午岭林区、黄龙山林区、山西吕梁以及太行山区。较降水指数相比,各站点气温指数变化趋势显著。

3)不同时间尺度的极端气候指数与NDVI相关性表现不同。年际变化中,NDVI 与极端气温指数(TMAXmeanTMINmeanTN90pTXxTNn)显著相关(p0.01);月尺度上,NDVI与极端降水指数(RX1dayRX5day)和极端气温指数(TMAXmeanTMINmeanTN90pTXxTNn)显著相关(p0.01);黄土高原地区NDVI与极端气温指数TMAXmeanTN10pTN90pTNxTXx1个月的相关性大于当月、前2个月、前3个月的相关性,说明植被变化对极端气候的响应具有一定滞后性。季节尺度,NDVI与极端降水指数未表现出明显相关性,而与极端气温指数显著相关;且春季和夏季的相关性高于秋季和冬季。

Other Abstract

Vegetation is the link connecting soil, water and atmosphere, and plays an important role in global climate change. As global warming, extreme climate occurs frequently and intensifieswhich will have an important impact on the growth of vegetation and leading to the change of vegetation cover. Based on the GIMMS NDVI data from 1982 to 1999, and MODIS NDVI data from 2000 to 2017 of the loess plateau, and the daily rainfall, daily maximum temperature and daily minimum temperature data of 87 meteorological stations, the study used Mann-Kendall trend test and correlation analysis method to analyze temporal and spatial changes of vegetation in Loess Plateau and its response to extreme climate. To study the dynamics changes of vegetation on the Loess Plateau and its response to extreme climate. Research indicates the following: 

1 The results showed that NDVI exhibited a significant increase trend in the loess plateau. From 1982 to 2017, NDVI on the Loess Plateau increased by an annual rate of 0.37% (p0.01). In the loess plateau, the seasonal variation of monthly NDVI was obvious. It started to grow in April and reaches a peak in August. After August, the NDVI value generally declines. Spatially, the vegetation in this region presented an increasing spatial distribution pattern from northwest to southeast on the Loess Plateau. Compared with 1982, the vegetation cover in the northwest of the loess plateau in 2017 has significantly improved, and the vegetation cover in the southeast of the high-value region also shows an increasing trend.

2 As for the change of extreme climate index, the extreme temperature index has a significant changetrend, while the significance test of extreme precipitation index was not obvious. The variation trend of extreme temperature index was relatively consistent and the extreme temperature index (SU25, TMAXmean, TMINmean, TN90p, TXx, TNn) represented extreme high temperature events showed a significant increase trend, and the index represented extreme low temperature events (FD0, TN10p) showed an extremely significant downward trend. However, the extreme precipitation index did not change significantly. The spatial distribution of extreme precipitation index (RX1day, RX5day, R50 mm, CDD) was relatively consistent, and they all showed the spatial distribution pattern increasing from northwest to southeast. The central and southeastern parts of the loess plateau have more precipitation, which is mainly distributed in ziwuling forest area, huanglongshan forest area, luliang of Shanxi Province and taihang mountain area. Compared with the precipitation index, the temperature index of each station has a significant change trend.

3 The correlation between NDVI and extreme climate index at different time scales was different. In the correlation analysis between extreme climate index and NDVI, the interannual variation of NDVI was significantly correlated with extreme temperature index (TMAXmean, TMINmean, TN90p, TXx, TNn) (p0.01). On the monthly scale, NDVI was significantly correlated with extreme precipitation index (RX1day, RX5day) and extreme temperature index (TMAXmean, TMINmean, TN90p, TXx, TNn) (p0.01). The correlation between NDVI and extreme temperature index TMAXmean, TN10p, TN90p, TNx and TXx a lag of one month is greater than that current month, a lag of two months and a lag of three mouth, indicating that the response of vegetation change to extreme climate has a certain lag. As the seasonal scale, there was no significant correlation between NDVI changes and extreme precipitation index in all seasons. However, NDVI presented a significant correlation with extreme temperature index, moreover, the correlation of spring and summer was higher than that autumn and winter.

MOST Discipline Catalogue工学
Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/9233
Collection水保所2018--2020届毕业生论文(学位论文、期刊论文)
Recommended Citation
GB/T 7714
韩丹丹. 黄土高原植被变化及其对极端气候的响应[D]. 中国科学院教育部水土保持与生态环境研究中心. 中国科学院大学,2020.
Files in This Item:
File Name/Size DocType Version Access License
韩丹丹-毕业论文终版.pdf(7333KB)学位论文 开放获取CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[韩丹丹]'s Articles
Baidu academic
Similar articles in Baidu academic
[韩丹丹]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[韩丹丹]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.