本文選題：荒漠化差值指數(shù)(DDI) + 時(shí)間序列趨勢(shì)擬合分析��； 參考：《電子科技大學(xué)》2015年碩士論文

【摘要】：根據(jù)聯(lián)合國(guó)資料:全球約35%的土地處于沙漠化威脅中,每年約2000萬(wàn)hm2耕地沙化,糧食減產(chǎn)12%~21%,年損失260億美元。日益加劇的荒漠化問(wèn)題對(duì)生態(tài)環(huán)境、人類生活、社會(huì)經(jīng)濟(jì)等方面造成嚴(yán)重影響,對(duì)于荒漠化程度的監(jiān)測(cè)以及荒漠化變化趨勢(shì)的分析成為全球關(guān)注的熱點(diǎn)�；哪F(xiàn)象在遙感影像上表現(xiàn)為裸露地表信息的增強(qiáng)和植被信息的減弱,可以采用地表反照率、地表溫度、地表濕度、植被覆蓋度等指標(biāo)因子表征。因此本文以MODIS數(shù)據(jù)為主要數(shù)據(jù)源,對(duì)全球的荒漠化程度進(jìn)行評(píng)價(jià),并對(duì)其變化趨勢(shì)進(jìn)行分析。首先,本文采用荒漠化差值指數(shù)(DDI)評(píng)價(jià)全球荒漠化程度。該方法以歸一化植被指數(shù)(NDVI)與地表反照率(Albedo)為監(jiān)測(cè)指標(biāo),建立Albedo-NDVI特征空間,并利用Albedo和NDVI的負(fù)相關(guān)性,構(gòu)建全球荒漠化差值指數(shù)(DDI)公式。在此基礎(chǔ)上,完成2000~2014年全球DDI專題產(chǎn)品,并將該產(chǎn)品用于全球荒漠化程度的評(píng)價(jià)。其次,針對(duì)全球、各大洲、全國(guó)以及全國(guó)各省市等不同區(qū)域完成2000~2014年的荒漠化程度評(píng)價(jià)及荒漠化變化趨勢(shì)分析。基于全球DDI專題產(chǎn)品,以分級(jí)圖的形式,直觀展現(xiàn)各區(qū)域的荒漠化狀況;基于全球DDI數(shù)據(jù),以像元為單位,通過(guò)時(shí)間序列趨勢(shì)擬合分析法,完成2000~2014年的全球DDI變化趨勢(shì)分布圖,并對(duì)各區(qū)域的DDI變化趨勢(shì)進(jìn)行分析;基于各區(qū)域的年度DDI均值變化曲線,完成2000~2014年各區(qū)域的DDI數(shù)據(jù)對(duì)比分析。最后,通過(guò)全球環(huán)境監(jiān)測(cè)指數(shù)(GEMI)與常用植被指數(shù)在植被覆蓋情況上的監(jiān)測(cè)效果,充分說(shuō)明GEMI可用于全球的植被狀況監(jiān)測(cè)。一方面完成全球GEMI專題產(chǎn)品,并用以評(píng)價(jià)全球植被覆蓋狀況。另一方面,基于2000~2014年的GEMI與DDI的年度均值變化趨勢(shì),對(duì)比分析DDI的監(jiān)測(cè)效果。論文結(jié)論:1、從2000到2014年,全球的植被覆蓋程度下降,荒漠化問(wèn)題加劇。2、全球的荒漠化分布與全球植被覆蓋的分布情況基本一致。具體表現(xiàn)如下:(1)以常綠闊葉林為主的赤道附近,植被覆蓋度高,DDI均值達(dá)1.45;(2)北美洲和亞洲的中高緯度地區(qū)主要植被類型是針葉林和落葉闊葉林,DDI均值在1.1~1.3左右,而北美洲東海岸和歐洲地區(qū)達(dá)到1.4;(3)各大洲近15年的DDI總體均值,從小到大,依次為:北美洲(0.70)、大洋洲(0.79)、非洲(0.96)、亞歐大陸(1.12)、南美洲(1.17)。
[Abstract]:According to the United Nations, about 35 percent of the world's land is under the threat of desertification. About 20 million hm2 of cultivated land is desertification each year, and the grain yield is reduced by 12% 21%, with an annual loss of $26 billion. The increasing problem of desertification has a serious impact on the ecological environment, human life, social economy and so on. The monitoring of the degree of desertification and the analysis of the trend of desertification have become the focus of global attention. The phenomenon of desertification in remote sensing images is characterized by the enhancement of bare surface information and the weakening of vegetation information, which can be characterized by surface albedo, surface temperature, surface humidity, vegetation coverage and so on. Therefore, using MODIS data as the main data source, the degree of desertification in the world is evaluated and the trend of desertification is analyzed. First of all, the desertification difference index DDI) is used to evaluate the degree of global desertification. In this method, the normalized vegetation index (NDVI) and surface albedo (Albedo) are used as monitoring indexes to establish the Albedo-NDVI feature space. Using the negative correlation of Albedo and NDVI, the global desertification difference index (DDI) formula is constructed. On this basis, the global DDI product is completed from 2000 to 2014, and the product is used to evaluate the degree of desertification in the world. Secondly, according to the different regions of the whole world, every continent, the whole country and the provinces and cities of the whole country, the evaluation of desertification degree and the analysis of the trend of desertification change from 2000 to 2014 are completed. Based on the global DDI thematic products, the desertification status of each region is visualized in the form of a hierarchical map. Based on the global DDI data, the trend distribution map of global DDI changes from 2000 to 2014 is completed through time series trend fitting analysis. Based on the annual DDI mean change curve of each region, the DDI data of each region from 2000 to 2014 are compared and analyzed. Finally, the global environmental monitoring index (GEMI) and the common vegetation index (GEMI) can be used to monitor vegetation status in the world. On the one hand, the global GEMI thematic products are completed and used to evaluate the global vegetation coverage. On the other hand, based on the trend of annual mean of GEMI and DDI from 2000 to 2014, the monitoring effect of DDI is analyzed. From 2000 to 2014, the degree of vegetation cover decreased and the problem of desertification increased. The global distribution of desertification was basically consistent with the distribution of global vegetation cover. The main vegetation types in the middle and high latitudes of North America and Asia are coniferous forests and deciduous broadleaved forests. The average DDI of each continent is from small to large in the last 15 years. The order of DDI is: North America 0.70, Oceania 0.79, Africa 0.96, Eurasia 1.12, South American 1.17.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X87;X171

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本文編號(hào)：2017681