肯尼亚Winum湾维多利亚湖的光谱反射率和藻华遥感监测

IF 0.3 4区 哲学 Q4 GEOSCIENCES, MULTIDISCIPLINARY
Vincent Ogembo, Gavin Akinyi Mohamed
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引用次数: 0

摘要

本研究旨在测量含有藻华和不同悬浮物的维多利亚湖淡水的原位光谱反射率。利用便携式光谱辐射计采集了维多利亚湖淡水水体340 ~ 1018 nm的反射光谱。数据是在9时12分至10时22分无云的一天收集的。在2022年10月27日太平洋夏令时(PDT),以阳光作为照明源,深色表面作为对照,获得近法向观测角度。利用谷歌地球引擎(Google Earth Engine, GEE)对维南湾维多利亚湖的卫星图像进行了分析,并采用NDCI指数技术对湖泊的叶绿素-a浓度进行了估算。维多利亚湖水体平均光谱的反射率在580 ~ 710 nm处最大,在430 nm附近最小,在740 nm以上最小。研究表明,NDCI值越高,叶绿素-a浓度越高,藻华越严重。平均而言,由于旱季气温较高,叶绿素-a浓度最高,为33 ~ 50mg/m 3,最高值出现在每年的1 ~ 2月。维多利亚湖的温纳姆湾的特点是由于湖岸的人为活动增加而引起的富营养化加剧。导致富营养化加剧的主要因素包括城市扩张、工业负荷和农业活动。因此,本研究呈现了维多利亚湖周围人类活动影响下湖泊的藻华情况和光谱反射率。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Spectral Reflectance and Algal Bloom Monitoring of Lake Victoria Using Remote Sensing Techniques, Winum Gulf of Kenya
: The study was aimed at measuring the in situ spectral reflectance of Lake Victoria fresh water which contains algal blooms and different suspended solids. Reflectance spectra of wavelengths 340-1,018 nm were collected from Lake Victoria fresh water using a portable spectroradiometer. The data was collected on a cloud free day between 0912 to 1022 hours. Sunlight was used as a source of illumination while dark surface was applied as control to obtain a near-normal angle of observation at a Pacific Daylight Time (PDT) on 27 th October 2022. Google Earth Engine (GEE) was used in analyzing the satellite images of Lake Victoria, Winam Gulf with NDCI index technique which provides an estimation of the chlorophyll-a concentration. The averaged spectrum of the Lake Victoria water showed reflectance maxima from 580-710 nm and reflectance minima near 430 nm and above 740 nm wavelengths. This study showed that the higher the NDCI value, the higher the concentration of chlorophyll-a , the more sever the algal bloom. On average, the concentration of chlorophyll-a was high at 33-50mg/m 3 and highest values recorded between January and February of every year due to high temperatures during the dry season. The Winum Gulf of Lake Victoria is characterized by increasing eutrophication arising from increased anthropogenic activities on the shores of the lake. Major factors contributing to the increased eutrophication include Urban sprawl, industrial loads and agricultural activities. The study, therefore, presents the algal bloom situation and spectral reflectance of the lake under the influence of human activities surrounding Lake Victoria.
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来源期刊
Earth Sciences History
Earth Sciences History GEOSCIENCES, MULTIDISCIPLINARY-HISTORY & PHILOSOPHY OF SCIENCE
CiteScore
1.00
自引率
0.00%
发文量
1
审稿时长
>12 weeks
期刊介绍: Earth Sciences History promotes and publishes historical work on all areas of the earth sciences – including geology, geography, geophysics, oceanography, paleontology, meteorology, and climatology. The journal honors and encourages a variety of approaches to historical study: biography, history of ideas, social history, and histories of institutions, organizations, and techniques. Articles are peer reviewed.
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