透過衛星資料探討地表特性與雲特徵之間的關聯性;Investigate the Linkage between Land Surface Properties and Cloud Characteristics from Satellite Data

NCUIR > Research Center > Master of Science Program in Remote Sensing Science and Technology > Electronic Thesis & Dissertation > Item 987654321/84229

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Title:	透過衛星資料探討地表特性與雲特徵之間的關聯性;Investigate the Linkage between Land Surface Properties and Cloud Characteristics from Satellite Data
Authors:	沈易;Shen, Yi
Contributors:	遙測科技碩士學位學程
Keywords:	中級解析度成像分光輻射度計;常態化差異植被指數;雲參數;氣候異常值;MODIS;Cloud Properties;NDVI;Anomaly
Date:	2020-07-28
Issue Date:	2020-09-02 18:31:24 (UTC+8)
Publisher:	國立中央大學
Abstract:	水文循環已表明地面特性與雲特徵之間具有一定的關連性，地表植被的變化可能與蒸散速率有關，藉此改變了降水模式和地表溫度，而降水型態也與雲的特徵有關。然而過往的研究中，較少地表特性影響雲微物理特徵的調查。因此，本研究主要探討雲微物理特徵如何受到地表植被的變化影響，特別針對森林砍伐及其恢復過程之情境。本研究選擇世界第三大島—婆羅洲，乃因該島近幾十年來森林砍伐率相當高，透過使用中級解析度成像分光輻射度計（MODIS）於2003 年至2018 年觀測的結果進行研究分析，利用常態化差異植被指數（NDVI）判別地表特性，並且進一步選擇雲量（CF）、雲頂氣壓（CTP）、雲光學厚度（COT）與雲滴有效粒徑（RE）等參數，探討地表與雲微物理間的關係。經由常態化差異植被指數的變化分析與前人研究進行比較，大致可將地表特性歸納為兩個時期: 棕櫚樹主導時期與混和林主導時期，並且進行氣候異常值年度、季度的差異與變化的分析。本研究結果發現，相較於混和林主導時期來說，棕櫚樹時期的雲特徵傾向於具有較大的雲滴粒徑、較厚的雲光學厚度、雲量較少且雲出現高度較低。在大多數情況下，棕櫚樹主導時期無論是乾季或是濕季，其氣候異常頻率都比混和林主導期更高，與季節變化相比，雲光學厚度和雲滴有效粒徑的氣候異常值對地表特徵的敏感性更高。整體結果表示若原始森林被大量砍伐或是改種植單一樹種(如同棕櫚樹的種植模式)，則可能加劇局地氣候中雲型態的異常情形。;The hydrological cycle has been proved that with the relationship between either land surface properties or cloud characteristics. The changes in surface vegetation might associate with the evapotranspiration rate, then further modify the precipitation pattern and surface temperature. On the other hand, precipitation type also has a relationship with clouds. However, there are not many studies on the response of cloud microphysical characteristics with land surface properties. Therefore, this study is focused on the investigation of the changes in surface vegetation that associates with cloud microphysical characteristics, in particular under the scenarios of deforesting and its recovery. The study area is the world′s third-largest island, Borneo, which has a large deforestation rate in recent decades. The satellite data is used Moderate-Resolution Imaging Spectroradiometer (MODIS) which adopted for study analysis from 2003 to 2018. The Normalized Difference Vegetation Index (NDVI) was applied to identify the land surface characteristics, while cloud fraction (CF), cloud top pressure (CTP), cloud optical thickness (COT), and cloud effective radius (RE) is adopted as the cloud microphysical features. Comparing the changes in NDVI with the previous studies that we can roughly divide data into two periods, one is the palm trees dominated and the other one is a mixed forest dominated. Trying to analyze the annual and seasonal climatology anomaly differences and changes in two types of land surface dominated. The results show that the characteristics of clouds tend to have larger cloud droplet sizes and optically thicker, less cloudy, and lower-level clouds during the palm tree dominated period than the mixed tree dominated. In most of the conditions, either dry or wet season, the palm tree dominant has a higher anomaly frequency than mixed tree dominant. The anomaly of COT and RE have a higher sensitivity to land properties than seasonal change. The overall results show that the deforestation of natural primary forests or planting single species of the palm may cause larger variability from the climatological cloud pattern over the study area.
Appears in Collections:	[Master of Science Program in Remote Sensing Science and Technology ] Electronic Thesis & Dissertation

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