Water clarity changes in Lake Taihu over 36 years based on Landsat TM and OLI observations

The Secchi disk depth (ZSD, m) has been used globally for many decades to represent water clarity and an index of water quality and eutrophication. In recent studies, a new theory and model were developed for ZSD, which enabled its semi-analytical remote sensing from the measurement of water color. Although excellent performance was reported for measurements in both oceanic and coastal waters, its reliability for highly turbid inland waters is still unknown. In this study, we extend this model and its evaluation to such environments. In particular, because the accuracy of the inherent optical properties (IOPs) derived from remote sensing reflectance (Rrs, sr−1) plays a key role in determining the reliability of estimated ZSD, we first evaluated a few quasi-analytical algorithms (QAA) specifically tuned for turbid inland waters and determined the one (QAATI) that performed the best in such environments. For the absorption coefficient at 443 nm (a(443), m−1) ranging from ~0.2 to 12.5 m−1, it is found that the QAATI-derived absorption coefficients agree well with field measurements (r2 > 0.85, and mean absolute percentage difference (MAPD) smaller than ~39%). Furthermore, with QAATI-derived IOPs, the MAPD was less than 25% between the estimated and field-measured ZSD (r2 > 0.67, ZSD in a range of 0.1–1.7 m). Furthermore, using matchup data between Rrs from the Medium Resolution Imaging Spectrometer (MERIS) and in-situ ZSD, a similar performance in the estimation of ZSD from remote sensing was obtained (r2 = 0.73, MAPD = 37%, ZSD in a range of 0.1–0.9 m). Based on such performances, we are confident to apply the ZSD remote sensing scheme to MERIS measurements to characterize the spatial and temporal variations of ZSD in Lake Taihu during the period of 2003–2011.

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Evaluating the impact of coastal land uses on water‐clarity conditions from Landsat TM/ETM+ imagery: Candarli Bay, Aegean Sea

International Journal of Remote Sensing ◽

10.1080/01431160500500326 ◽

2006 ◽

Vol 27 (17) ◽

pp. 3627-3643 ◽

Cited By ~ 8

Author(s):

E. Ucuncuoglu ◽

O. Arli ◽

A. H. Eronat

Keyword(s):

Aegean Sea ◽

Water Clarity ◽

Landsat Tm ◽

Land Uses ◽

The Impact ◽

Coastal Land

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LBA-ECO LC-09 LANDSAT TM AND ETM+ DATA, SITES IN RONDONIA AND PARA, BRAZIL: 1985-2004

ORNL Distributed Active Archive Center Datasets ◽

10.3334/ornldaac/987 ◽

2010 ◽

Author(s):

E.S. BRONDIZIO, ◽

E.F. MORAN

Keyword(s):

Landsat Tm

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APLIKASI CITRA LANDSAT 8 OLI UNTUK IDENTIFIKASI STATUS TROFIK WADUK GAJAH MUNGKUR WONOGIRI, JAWA TENGAH

MAJALAH ILMIAH GLOBE ◽

10.24895/mig.2017.19-2.633 ◽

2017 ◽

Vol 19 (2) ◽

pp. 113

Author(s):

Kusuma Wardani Laksitaningrum ◽

Wirastuti Widyatmanti

Keyword(s):

Chlorophyll A ◽

Total Phosphorus ◽

Trophic State ◽

Water Clarity ◽

Coefficient Of Determination ◽

Physical Factors ◽

Landsat 8 ◽

Trophic State Index ◽

Landsat 8 Oli ◽

State Index

ABSTRAKWaduk Gajah Mungkur (WGM) adalah bendungan buatan yang memiliki luas genangan maksimum 8800 ha, terletak di Desa Pokoh Kidul, Kecamatan Wonogiri, Kabupaten Wonogiri. Kondisi perairan WGM dipengaruhi oleh faktor klimatologis, fisik, dan aktivitas manusia yang dapat menyumbang nutrisi sehingga mempengaruhi status trofiknya. Tujuan dari penelitian ini adalah mengkaji kemampuan citra Landsat 8 OLI untuk memperoleh parameter-parameter yang digunakan untuk menilai status trofik, menentukan dan memetakan status trofik yang diperoleh dari citra Landsat 8 OLI, dan mengevaluasi hasil pemetaan dan manfaat citra penginderaan jauh untuk identifikasi status trofik WGM. Identifikasi status trofik dilakukan berdasarkan metode Trophic State Index (TSI) Carlson (1997) menggunakan tiga parameter yaitu kejernihan air, total fosfor, dan klorofil-a. Model yang diperoleh berdasar pada rumus empiris dari hasil uji regresi antara pengukuran di lapangan dan nilai piksel di citra Landsat 8 OLI. Model dipilih berdasarkan nilai koefisien determinasi (R2) tertinggi. Hasil penelitian merepresentasikan bahwa nilai R2 kejernihan air sebesar 0,813, total fosfor sebesar 0,268, dan klorofil-a sebesar 0,584. Apabila nilai R2 mendekati 1, maka semakin baik model regresi dapat menjelaskan suatu parameter status trofik. Berdasarkan hasil kalkulasi diperoleh distribusi yang terdiri dari kelas eutrofik ringan, eutrofik sedang, dan eutrofik berat yaitu pada rentang nilai indeks 50,051 – 80,180. Distribusi terbesar adalah eutrofik sedang. Hal tersebut menunjukkan tingkat kesuburan perairan yang tinggi dan dapat membahayakan makhluk hidup lain.Kata kunci: Waduk Gajah Mungkur, citra Landsat 8 OLI, regresi, TSI, status trofikABSTRACTGajah Mungkur Reservoir is an artificial dam that has a maximum inundated areas of 8800 ha, located in Pokoh Kidul Village, Wonogiri Regency. The reservoir’s water conditions are affected by climatological and physical factors, as well as human activities that can contribute to nutrients that affect its trophic state. This study aimed to assess the Landsat 8 OLI capabilities to obtain parameters that are used to determine its trophic state, identifying and mapping the trophic state based on parameters derived from Landsat 8 OLI, and evaluating the results of the mapping and the benefits of remote sensing imagery for identification of its trophic state. Identification of trophic state is based on Trophic State Index (TSI) Carlson (1997), which uses three parameters there are water clarity, total phosphorus, and chlorophyll-a. The model is based on an empirical formula of regression between measurements in the field and the pixel values in Landsat 8 OLI. Model is selected on the highest value towards coefficient of determination (R2). The results represented that R2 of water clarity is 0.813, total phosphorus is 0.268, and chlorophyll-a is 0.584. If R2 close to 1, regression model will describe the parameters of the trophic state better. Based on the calculation the distribution consists of mild eutrophic, moderate eutrophic, and heavy eutrophic that has index values from 50.051 to 80.18. The most distribution is moderate eutrophication, and it showed the high level of trophic state and may harm other living beings.Keywords: Gajah Mungkur Reservoir, Landsat 8 OLI satellite imagery, regression, TSI, trophic state

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ANALISIS PERUBAHAN PENUTUP LAHAN DAN POLA MATA PENCAHARIAN MASYARAKAT Studi Kasus: Kecamatan Kelapa Kampit, Kabupaten Belitung Timur

Seminar Nasional Geomatika ◽

10.24895/sng.2018.3-0.980 ◽

2019 ◽

Vol 3 ◽

pp. 405

Author(s):

Emma Rahmawati ◽

Anang Dwi Purwanto

Keyword(s):

Landsat Tm ◽

Landsat 8

Kegiatan penambangan timah di daratan di wilayah Kabupaten Belitung Timur sudah berlangsung sejak lama terutama di wilayah Kecamatan Kelapa Kampit. Banyak penduduknya bekerja sebagai penambang timah, namun kegiatan penambangan tersebut semakin berkurang seiring dengan adanya kebijakan terkait penambangan yang lebih ke arah pelestarian lingkungan dan adanya kegiatan reklamasi dan revegetasi yang dilakukan di lahan pasca tambang timah. Tujuan penelitian ini adalah untuk menganalisis gambaran perubahan penutup lahan dan menganalisis pola matapencaharian di Kecamatan Kelapa Kampit. Data penelitian yang digunakan terdiri dari data primer dan data sekunder. Data primer di antaranya berupa citra satelit Landsat TM akuisisi tahun 1995 dan Landsat 8 akuisisi tahun 2015 serta data hasil wawancara penduduk lokal. Data sekunder berupa data data dari pemerintah daerah setempat, dan lain-lain. Metode pemisahan obyek penutup lahan menggunakan teknik klasifikasi unsupervised (klasifikasi tak terbimbing). Setelah dilakukan proses reclass, maka dihasilkan 8 (delapan) kelas penutup lahan diantaranya: Awan (no data), Hutan, Ladang/Semak, lahan tambang, permukiman, perkebunan dan tubuh air. Analisis deskriptif kualitatif dilakukan untuk melihat hubungan perubahan penutup lahan dengan pola mata pencaharian masyarakat. Hasil penelitian menunjukkan terjadi kondisi yang kontradiktif antara lahan tambang dan hutan dengan lahan perkebunan kelapa sawit. Kondisi luasan lahan tambang dan hutan dari tahun 1994 – 2015 mengalami penurunan, sedangkan luasan lahan perkebunan kelapa sawit mengalami peningkatan yang cukup signifikan. Seiring dengan perubahan penutup lahan tersebut, terjadi penurunan jumlah buruh harian lepas dimana penambang inkonvensional termasuk didalamnya. Terjadi peralihan mata pencaharian yang awalnya mengandalkan penambangan, saat ini menjadi semakin banyak pilihan mata pencaharian yang dapat dipilih oleh masyarakat Kecamatan Kelapa Kampit.

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A STUDY ON THE URBANIZATION OF HARBIN AND SHANGHAI BY LANDSAT TM DATA

Journal of Environmental Engineering (Transactions of AIJ) ◽

10.3130/aije.70.91_2 ◽

2005 ◽

Vol 70 (595) ◽

pp. 91-96

Author(s):

Minghao PIAO ◽

Ikuo SAITO ◽

Osamu ISHIHARA

Keyword(s):

Landsat Tm

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Water Quality Trends in Hamilton Harbour: 1987 to 1995

Water Quality Research Journal ◽

10.2166/wqrj.1996.027 ◽

1996 ◽

Vol 31 (3) ◽

pp. 473-484 ◽

Cited By ~ 9

Author(s):

Murray N. Charlton ◽

Robin Le Sage

Keyword(s):

Algal Blooms ◽

Action Plan ◽

Secchi Depth ◽

Water Clarity ◽

Nutrient Loads ◽

Hamilton Harbour ◽

Near Shore ◽

The Media ◽

Park Area ◽

Water Quality Trends

Abstract A series of water samples and Secchi depth measurements were conducted in Hamilton Harbour between 1987 and 1995. The data indicate little recent improvement in the harbour generally. Detection of real improvements may require high frequency sampling and a more extensive sample grid once a cause for improvement is in place. Some measures, such as chlorophyll and Secchi depth, approach RAP initial goals sometimes during recent years, but algal blooms still occur, which prevent attainment of satisfactory average conditions. The cause of aesthetic improvements in water clarity reported in the media was investigated with sampling along an inshore-offshore transect and intense Secchi measurements in the LaSalle Park area. The data are consistent with a transient clarifying effect of zebra mussels on structures near shore. The need to reduce nutrient loads as recommended in the Remedial Action Plan continues.

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Spatial and Temporal Water Quality Trends in Severn Sound, Georgian Bay, since the Introduction of Phosphorus Control Guidelines: Nutrients and Phytoplankton, 1973 to 1991

Water Quality Research Journal ◽

10.2166/wqrj.1995.044 ◽

1995 ◽

Vol 30 (4) ◽

pp. 565-592 ◽

Cited By ~ 1

Author(s):

A.F. Gemza

Keyword(s):

Total Phosphorus ◽

Sewage Treatment ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Soluble Reactive Phosphorus ◽

Euphotic Zone ◽

Water Clarity ◽

Sewage Treatment Plants ◽

Order Of Magnitude ◽

Phosphorus Levels

Abstract Severn Sound continues to exhibit signs of eutrophication despite initial identification of the problem in 1969 and the construction of several sewage treatment plants since then. In general, improvements in trophic state indicators have been marginal, suggesting that the sewage treatment plants have had limited success in controlling phosphorus concentrations. These discharges likely contributed to the increased total phosphorus levels and consequently the higher phytoplankton densities of the nearshore waters. Phytoplankton biovolumes were on average one order of magnitude higher than in the open waters of Lake Huron with mean summer biovolumes as high as 8.0 mm/L. Algal biovolumes were most dense in Penetang Bay, which experienced limited exchange with the main waters of the sound. No significant long-term trends were observed. Water clarity was declining significantly, however, at a rate of -0.60 to -0.78 m/year throughout the sound except in Sturgeon Bay. Total phosphorus levels were highly variable from year to year; however, concentrations from a 20-year perspective were declining in the open waters at a rate of 0.70 µg/L/year, but response was limited in nearshore areas. In Sturgeon Bay, mean annual euphotic zone total phosphorus as well as soluble reactive phosphorus levels declined by as much as 50% following the construction of a sewage treatment plant with tertiary treatment. Phytoplankton genera typical of eutrophic waters continued to dominate the algal assemblage but members indicative of mesotrophic conditions have become apparent in some areas of the sound.

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