Assessing the utility of spectral band operators to reduce the influence of total suspended solids on the relationship between chlorophyll concentration and the bidirectional reflectance factor in Amazon waters

2004 ◽  
Vol 25 (22) ◽  
pp. 5105-5115 ◽  
Author(s):  
E. M. L. M. Novo ◽  
W. Pereira Filho ◽  
J. M. Melack
Keyword(s):  
Suspended Solids ◽  
Spectral Band ◽  
Chlorophyll Concentration ◽  
Total Suspended Solids ◽  
Bidirectional Reflectance ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
The Relationship

scholarly journals Comparative assessment of the relationship between coliform bacteria and water geochemistry in surface and ground water systems

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257715
Author(s):  
Simon Appah Aram ◽  
Benjamin M. Saalidong ◽  
Patrick Osei Lartey
Keyword(s):  
Heavy Metals ◽  
Ground Water ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Total Coliform ◽  
Water Systems ◽  
Water Sources ◽  
Faecal Coliform ◽  
Lower Odds ◽  
The Relationship

The occurrence of pollution indicator bacteria (total and faecal coliform) has been used as a sanitary parameter for evaluating the quality of drinking water. It is known that these indicators are associated with disease causing organisms which are of great concern to public health. This study assessed the relationship between coliform bacteria and water geochemistry in surface and ground water systems in the Tarkwa mining area using logistic regression models. In surface water sources, higher values of chloride (OR = 0.891, p<005), phosphates (OR = 0.452, p<0.05), pH (OR = 0.174, p<0.05) and zinc (OR = 0.001, p<0.05) were associated with lower odds of faecal coliform contamination. In groundwater sources, higher values of phosphates (OR = 0.043, p<0.001), total dissolved solids (OR = 0.858, p<0.05), turbidity (OR = 0.996, p<0.05) and nickel (OR = 6.09E-07, p<0.05) implied non-contamination by faecal coliform. However, higher values of electrical conductivity (OR = 1.097, p<0.05), nitrates (OR = 1.191, p<0.05) and total suspended solids (OR = 1.023, p<0.05) were associated with higher odds of faecal coliform contamination of groundwater sources. Nitrates and total suspended solids, in this case, were completely mediated by the heavy metals. For total coliform in surface water systems, higher values of magnesium (OR = 1.070, p<0.05) was associated with higher odds of total coliform contamination while higher values of phosphates (OR = 0.968, p<0.05) was associated with lower odds of total coliform contamination although the presence of heavy metals completely mediated these relationships. For ground water systems, higher values of pH (OR = 0.083, p<0.05), phosphates (OR = 0.092, p<0.05), turbidity (OR = 0.950, p<0.05) and chloride (OR = 0.860, p<0.05) were associated with lower odds of total coliform contamination. However, higher values of total suspended solids (OR = 1.054, p<0.05) and nitrates (OR = 1.069, p<0.05) implied contamination of total coliform in ground water sources. The relationship between nitrates and total coliform were mediated by the heavy metals. This study establishes the need to monitor, manage and remediate surface and ground water sources for potential disease causing microbes in ways that takes into consideration the factors that create different conditions in the two water systems. This study validates the usefulness of statistical models as tools for preventing surface and ground water contamination.

Simulation and Sensibility Analysis of Earth Surface Bidirectional Reflectance Factor Based on Radiosity

2018 ◽  
Vol 55 (9) ◽  
pp. 092802
Author(s):  
甄治钧 Zhen Zhijun ◽  
陈圣波 Chen Shengbo ◽  
覃文汉 Qin Wenhan ◽  
李健 Li Jian ◽  
孟凡晓 Meng Fanxiao ◽  
...  
Keyword(s):  
Earth Surface ◽  
Bidirectional Reflectance ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
Sensibility Analysis

Effect of soil surface roughness and scene components on soil surface bidirectional reflectance factor

2012 ◽  
Vol 92 (2) ◽  
pp. 297-313 ◽  
Author(s):  
Z. Wang ◽  
C. A. Coburn ◽  
X. Ren ◽  
P. M. Teillet
Keyword(s):  
Surface Roughness ◽  
Rough Surface ◽  
Zenith Angle ◽  
Smooth Surface ◽  
Soil Surface ◽  
Bidirectional Reflectance ◽  
Imaging Spectrometer ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
Soil Surface Roughness

Wang, Z., Coburn, C. A., Ren, X. and Teillet, P. M. 2012. Effect of soil surface roughness and scene components on soil surface BRF. Can. J. Soil Sci. 92: 297–313. Bidirectional Reflectance factor (BRF) data of both rough [surface roughness index (SRI) of 51%] and smooth soil surfaces (SRI of 5%) were acquired in the laboratory under 30° illumination zenith angle using a Specim V10E imaging spectrometer and an Ocean Optics non-imaging spectrometer mounted on the University of Lethbridge Goniometer System version 2.5 (ULGS-2.5) and version 2.0 (ULGS-2.0), respectively. Under controlled laboratory conditions, the rough soil surface exhibited higher spectral reflectance than the smooth surface for most viewing angles. The BRF of the rough surface varied more than the smooth surface as a function of the viewing zenith angle. The shadowing effect was stronger for the rough surface than for the smooth surface and was stronger in the forward-scattering direction than in the backscattering direction. The pattern of the BRF generated with the non-image based data was similar to that generated with the whole region of interest (ROI) of the image-based data, and that of the whole ROI of the image-based data was similar to that of the illuminated scene component. The BRF of the smooth soil surface was dominated by illuminated scene component, i.e., the sunlit pixels, whereas the shaded scene component, i.e., the shaded pixels, was a larger proportion of the BRF of the rough soil surface. The image-based approach allowed the characterization of the contribution of spatial components in the field of view to soil BRF and improved our understanding of soil reflectance.

scholarly journals Instantaneous Top-of-Atmosphere Albedo Comparison between CERES and MISR over the Arctic

2018 ◽  
Vol 10 (12) ◽  
pp. 1882 ◽  
Author(s):  
Yizhe Zhan ◽  
Larry Di Girolamo ◽  
Roger Davies ◽  
Catherine Moroney
Keyword(s):  
Solar Zenith Angle ◽  
Radiant Energy ◽  
Energy System ◽  
Radiation Budget ◽  
The Arctic ◽  
Bidirectional Reflectance ◽  
Retrieval Accuracy ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
Relative Root

The top-of-atmosphere (TOA) albedo is one of the key parameters in determining the Arctic radiation budget, with continued validation of its retrieval accuracy still required. Based on three years (2007, 2015, 2016) of summertime (May–September) observations from the Clouds and the Earth’s Radiant Energy System (CERES) and the Multi-angle Imaging SpectroRadiometer (MISR), collocated instantaneous albedos for overcast ocean and snow/ice scenes were compared within the Arctic. For samples where both instruments classified the scene as overcast, the relative root-mean-square (RMS) difference between the sample albedos grew as the solar zenith angle (SZA) increased. The RMS differences that were purely due to differential Bidirectional Reflectance Factor (BRF) anisotropic corrections ( σ A D M ) were estimated to be less than 4% for overcast ocean and overcast snow/ice when the SZA ≤ 70°. The significant agreement between the CERES and MISR strongly increased our confidence in using the instruments overcast cloud albedos in Arctic studies. Nevertheless, there was less agreement in the cloud albedos for larger solar zenith angles, where the RMS differences of σ A D M reached 13.5% for overcast ocean scenes when the SZA > 80°. Additionally, inconsistencies between the CERES and MISR scene identifications were examined, resulting in an overall recommendation for improvements to the MISR snow/ice mask and a rework of the MISR Albedo Cloud Designation (ACD) field by incorporating known strengths of the standard MISR cloud masks.

Sign in / Sign up

Export Citation Format

Share Document