Environmental characterization of a hypersaline coastal lagoon from Landsat-5 Thematic Mapper data

2003 ◽  
Vol 24 (16) ◽  
pp. 3219-3234 ◽  
Author(s):  
C. Z. F. Braga ◽  
M. L. Vianna ◽  
B. Kjerfve
1987 ◽  
Vol 9 ◽  
pp. 104-108 ◽  
Author(s):  
D.K. Hall ◽  
J.P. Ormsby ◽  
R.A. Bindschadler ◽  
H. Siddalingaiah

Landsat Thematic Mapper (TM) data have been analyzed to study the reflectivity characteristics of three glaciers: the Grossglockner mountain group of glaciers in Austria and the McCall and Meares Glaciers in Alaska, USA. The ratio of TM band 4 (0.76–0.90 μm) to TM band 5 (1.55–1.75 μm) was found to be useful for enhancing reflectivity differences on the glaciers. Using this ratio, distinct zones of similar reflectivity were noted on the Grossglockner mountain group of glaciers and on the Meares Glacier; no distinct zones were observed on the McCall Glacier. On the TM subscene containing the Grossglockner mountain group of glaciers, 28.2% of the glacierized area was determined to be in the zone corresponding most closely to the ablation area, and 71.8% with the location of the accumulation area. Using these measurements, the glacier system has an accumulation area ratio (AAR) of approximately 0.72. Within the accumulation area, two zones of different reflectivity were delineated. Radiometric surface temperatures were measured using TM band 6 (10.4–12.5 μm) on the Grossglockner mountain group of glaciers and on the Meares Glacier. The average radiometric surface temperature of the Grossglockner mountain group of glaciers decreased from 0.9 ± 0.34 °C in the ablation area, to −0.9 ± 0.83 C in the accumulation area.


2019 ◽  
Vol 11 (1) ◽  
pp. 34-45
Author(s):  
Iug LOPES ◽  
Clovis Manoel Carvalho RAMOS ◽  
Brauliro Gonçalves LEAL ◽  
Douglas Alberto de Oliveira SILVA

As zonas rurais e urbanas estão passando por transformações do uso do solo de forma significativa. Estas mudanças têm afetado o uso da terra, principalmente nas áreas marginas às urbanas. É ao longo destas áreas onde o processo de expansão urbana entra em conflito com o uso da terra para fins agrícolas. Um recurso inestimável neste contexto é o sensoriamento remoto, que aparece como uma ferramenta de avaliação dos processos de transformação territórial. Técnicas de observação de dados adquiridos por satélites em variação temporal e espacial possuem potencial de detectar, identificar e mapear as mudanças no uso da terra. O objetivo do trabalho foi realizar uma caracterização atual do uso da terra e análise espaço-temporal das modificações ao longo dos períodos de 2000 a 2010, 2010 a 2015 e 2000 a 2015, na Bacia do Rio Pontal, usando dados Landsat Thematic Mapper (TM). De acordo com os resultados obtidos, pode-se concluir que na região estudada houve um crescimento considerável de área destinada à agricultura irrigada, redução das áreas de caatinga densa ou substituição da mesma por caatinga aberta e solo exposto e por fim se observou a redução dos corpos hídricos da região.


1987 ◽  
Vol 9 ◽  
pp. 104-108 ◽  
Author(s):  
D.K. Hall ◽  
J.P. Ormsby ◽  
R.A. Bindschadler ◽  
H. Siddalingaiah

Landsat Thematic Mapper (TM) data have been analyzed to study the reflectivity characteristics of three glaciers: the Grossglockner mountain group of glaciers in Austria and the McCall and Meares Glaciers in Alaska, USA. The ratio of TM band 4 (0.76–0.90 μm) to TM band 5 (1.55–1.75 μm) was found to be useful for enhancing reflectivity differences on the glaciers. Using this ratio, distinct zones of similar reflectivity were noted on the Grossglockner mountain group of glaciers and on the Meares Glacier; no distinct zones were observed on the McCall Glacier. On the TM subscene containing the Grossglockner mountain group of glaciers, 28.2% of the glacierized area was determined to be in the zone corresponding most closely to the ablation area, and 71.8% with the location of the accumulation area. Using these measurements, the glacier system has an accumulation area ratio (AAR) of approximately 0.72. Within the accumulation area, two zones of different reflectivity were delineated. Radiometric surface temperatures were measured using TM band 6 (10.4–12.5 μm) on the Grossglockner mountain group of glaciers and on the Meares Glacier. The average radiometric surface temperature of the Grossglockner mountain group of glaciers decreased from 0.9 ± 0.34 °C in the ablation area, to −0.9 ± 0.83 C in the accumulation area.


Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1863
Author(s):  
Luciana Cristina de Carvalho Santa-Rosa ◽  
Sibelle Trevisan Disaró ◽  
Violeta Totah ◽  
Silvia Watanabe ◽  
Ana Tereza Bittencourt Guimarães

Living benthic foraminifera (>63 µm) were studied to characterize the continental slope of the Potiguar Basin (SW Atlantic). Foraminifers from the surface (0–2 cm), subsurface (2–5 cm), and integrated (0–5 cm) sediment layers were analyzed to verify their contribution to environmental characterization. It was also estimated if and which changes occur when the subsurface is added. Sampling stations were distributed in five transects in four isobaths (150, 400, 1000, and 2000 m). Sediment samples were fixed with 4% buffered formaldehyde and stained with Bengal rose. Were recorded 396 species in the surface layer, 228 in the subsurface, and 449 in integrating both layers. This study did not include tubular agglutinated species. The assemblages from 150 m isobath indicated the upper slope, from 400 m indicated the middle slope and the ones from the 2000 m indicated the lower slope. The surface layer’s assemblage at 1000 m isobath was more similar to the middle slope; in contrast, its subsurface layer´s assemblage had more similarity with the lower slope. Rarefaction curves, Permanova, and NMDS routines indicated a high resemblance between surface and integrated layers. Therefore, the first two centimeters were sufficient to characterize this region based on living benthic foraminifera.


2019 ◽  
Vol 32 (1) ◽  
pp. 200-210
Author(s):  
Antônio Italcy de Oliveira Júnior ◽  
Luiz Alberto Ribeiro Mendonça ◽  
Sávio de Brito Fontenele ◽  
Adriana Oliveira Araújo ◽  
Maria Gorethe de Sousa Lima Brito

ABSTRACT Soil is a dynamic and complex system that requires a considerable number of samples for analysis and research purposes. Using multivariate statistical methods, favorable conditions can be created by analyzing the samples, i.e., structural reduction and simplification of the data. The objective of this study was to use multivariate statistical analysis, including factorial analysis (FA) and hierarchical groupings, for the environmental characterization of soils in semiarid regions, considering anthropic (land use and occupation) and topographic aspects (altitude, moisture, granulometry, PR, and organic-matter content). As a case study, the São José Hydrographic Microbasin, which is located in the Cariri region of Ceará, was considered. An FA was performed using the principal component method, with normalized varimax rotation. In hierarchical grouping analysis, the “farthest neighbor” method was used as the hierarchical criterion for grouping, with the measure of dissimilarity given by the “square Euclidean distance.” The FA indicated that two factors explain 75.76% of the total data variance. In the analysis of hierarchical groupings, the samples were agglomerated in three groups with similar characteristics: one with samples collected in an area of the preserved forest and two with samples collected in areas with more anthropized soils. This indicates that the statistical tool used showed sensitivity to distinguish the most conserved soils and soils with different levels of anthropization.


1992 ◽  
Vol 61 (3) ◽  
pp. 527-535 ◽  
Author(s):  
Yoichi TORIGOE ◽  
Tetsuro AMANO ◽  
Kei OGAWA ◽  
Michikazu FUKUHARA

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