本文選題：洞庭湖區(qū)　切入點：濕地　出處：《湖南農(nóng)業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：洞庭湖是我國第二大淡水湖,對區(qū)域氣候調(diào)節(jié)和生態(tài)環(huán)境穩(wěn)定起著極其關(guān)鍵的作用。然而,受全球變暖及其它因素的影響,洞庭湖濕地面積急劇減少,濕地功能退化嚴重,生態(tài)系統(tǒng)受到嚴重影響。為了更好地認識洞庭湖區(qū)濕地以及地表溫度的時空變化特征,弄清洞庭湖對“全球變暖”現(xiàn)象的響應(yīng)特征、探明濕地變化對地表溫度的影響。本文利用1995、2001、2004和2013四年的冬季TM/ETM+遙感影像,采用遙感(RS)、地理信息系統(tǒng)(GIS)、數(shù)理統(tǒng)計等方法分析了洞庭湖區(qū)的濕地演變特征、地表溫度(LST)時空變化特征以及濕地變化對溫度的影響。結(jié)果表明：(1)洞庭湖區(qū)景觀類型以水田、旱地、林地為主,水體次之。1995-2013期間,濕地面積逐年減少,尤其是水體面積的減少,由2670.59km2到2078.12km2。各類型之間轉(zhuǎn)化關(guān)系復(fù)雜,主要表現(xiàn)在水田轉(zhuǎn)化為建設(shè)用地和旱地,旱地轉(zhuǎn)化為林地,水體轉(zhuǎn)變?yōu)椴轂┑�、蘆葦灘地、泥沙灘地。(2)洞庭湖區(qū)景觀破碎化程度和景觀類型形狀不規(guī)則性不斷加大。各景觀類型中,水田、建設(shè)用地、水體和旱地結(jié)構(gòu)發(fā)生明顯變化,蘆葦灘地、草灘地景觀結(jié)構(gòu)較穩(wěn)定。(3)LST主要以中溫區(qū)、較高溫區(qū)和較低溫區(qū)為主,各等級面積呈正態(tài)分布,低溫區(qū)主要分布在水體,高溫區(qū)沒有明顯的空間分布特征。1995-2013年,冬季平均地表溫度增加約3.5℃,空間差異性減小。不同區(qū)域?qū)θ蜃兣?yīng)的響應(yīng)程度表現(xiàn)為東洞庭湖區(qū)南洞庭湖區(qū)西洞庭湖區(qū)。(4)濕地類型平均LST比非濕地類型的低,水體對周圍熱環(huán)境有一定的降溫調(diào)節(jié)作用,當(dāng)水體面積1 km2時,對周圍熱環(huán)境影響距離約在300m左右。(5)冬季,水汽是影響地表溫度最重要的因素。歸一化植被指數(shù)(NDVI)與地表溫度關(guān)系不明顯；歸一化水汽指數(shù)(NDMI)與地表溫度呈顯著負相關(guān)關(guān)系,尤其在NDMI值為0.2～0.5時；DEM在65米時,與LST呈正相關(guān)性,65～365m相關(guān)性不明顯,365m時呈負相關(guān)性,但程度較小。
[Abstract]:Dongting Lake is the second largest freshwater lake in China, which plays a key role in regional climate regulation and ecological environment stability. However, due to global warming and other factors, the wetland area of Dongting Lake has been reduced sharply, and the wetland function has been degraded seriously. The ecosystem is seriously affected. In order to better understand the temporal and spatial variation characteristics of wetland and surface temperature in Dongting Lake region, and to find out the response characteristics of Dongting Lake to the phenomenon of "global warming", The effects of wetland changes on surface temperature were investigated. The characteristics of wetland evolution in Dongting Lake region were analyzed by using TM/ETM remote sensing images in winter of 1995 / 2001 and 2013, using remote sensing, GIS and mathematical statistics, etc. The results showed that the landscape types of Dongting Lake were paddy field, dryland and woodland, and the area of wetland decreased year by year, especially the area of water body, in the period of 1995-2013. From 2670.59 km ~ 2 to 2078.12 km ~ 2. The transformation relationship between different types is complex, mainly manifested in the transformation of paddy field into construction land and dry land, dryland into forest land, water body into grass beach, Reed beach, etc. The degree of landscape fragmentation and the irregularity of landscape type in Dongting Lake region are increasing. Among the landscape types, the structure of paddy field, construction land, water body and dry land are obviously changed. The landscape structure of grass beach is more stable. The main LST is middle temperature area, higher temperature area and lower temperature area, each grade area is normal distribution, low temperature area mainly distributes in water body, and there is no obvious spatial distribution characteristic in high temperature area from 1995 to 2013. The average surface temperature increased about 3.5 鈩，

本文編號：1565651