scholarly journals MODIS-Based Investigation of Flood Areas in Southern Cambodia from 2002–2013

Environments ◽  
2019 ◽  
Vol 6 (5) ◽  
pp. 57 ◽  
Author(s):  
Nguon Vichet ◽  
Kensuke Kawamura ◽  
Dung Phan Trong ◽  
Nguyen Van On ◽  
Zhe Gong ◽  
...  
Keyword(s):  
Land Cover ◽  
Rainy Season ◽  
Negative Impact ◽  
Agricultural Productivity ◽  
Mekong Delta ◽  
Temporal Distribution ◽  
Water Shortage ◽  
Flood Inundation ◽  
Landsat Images ◽  
Spatio Temporal

In Cambodia and the Vietnamese Mekong Delta, floods commonly occur during the rainy season, and a better understanding of their spatio-temporal distribution is important for both disaster prevention and the improvement of agricultural production. This study investigated spatio-temporal flood inundation and land cover change from 2002 to 2013 in the southern part of Cambodia using Terra satellite on-board Moderate Resolution Imaging Spectroradiometer (MODIS) images. The algorithm for flood inundation detection, WFFI (Wavelet-based Filter for detecting spatio-temporal changes in Flood Inundation) was used, and the parameters were modified to fit the present study. The estimated inundation areas were validated using eight Landsat images. In a comparison between the original and modified WFFIs, the modified WFFI (70–96%) exhibited better accuracy than the original WFFI (30–70%). Overall, the temporal change in the flood inundation area presented a decreasing trend, and a link to the in-situ observed water level showed a decreasing trend during the rainy season. Furthermore, the estimated flood inundation exhibited a significant delay since 2008. Based on the yearly land cover MODIS product, the permanent water body and wetland areas decreased, whereas the cropland areas increased. This was as a result of increased agricultural productivity. However, water shortage was the major obstacle to increasing agricultural productivity, and it also had a negative impact on aquatic ecology, such as fish spawning grounds.

Composition and spatio-temporal variation in the density of the Brachyura (Decapoda, Pleocyemata) in the rocky substrates of an Amazonian estuary

Crustaceana ◽  
2016 ◽  
Vol 89 (13) ◽  
pp. 1447-1466 ◽  
Author(s):  
Priscila S. V. Nóbrega ◽  
Jussara M. Martinelli-Lemos
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Rainy Season ◽  
Multivariate Analyses ◽  
Temporal Distribution ◽  
Homogeneous Distribution ◽  
Influence Of Temperature ◽  
Spatio Temporal ◽  
Outer Estuary ◽  
Saline Zone

The present study investigated the composition, spatio-temporal distribution, and the influence of temperature and salinity on the density of brachyurans associated with rocky substrates in an estuary of the Brazilian Amazonian coast. Specimens were collected monthly at four sites representing the two margins (profiles), zones (inner and outer estuary) and the lower and upper mediolittoral portions at each site of the Marapanim estuary. A total of 14 species were collected and multivariate analyses revealed that the species composition varied systematically between zones, margins, mediolittoral sectors and seasons, with the more saline zone, the most eroded margin, the lower mediolittoral, and the rainy season all being characterized by higher densities and a more homogeneous distribution of species. In general, high densities of brachyurans, but low species richness, and marked dominance characterized the sites. Salinity proved to play an important role in the structuring of the community.

scholarly journals Contribution à l’étude de la vulnérabilité des terres de cultures de la région de Thiès (Sénégal) à l’aide de la télédétection et des systèmes d’information géographique (SIG)

2019 ◽  
pp. 6731-6746 ◽  
Author(s):  
Amadou SALL ◽  
Assize TOURE ◽  
Alioune KANE ◽  
Awa Niang Fall
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Land Cover ◽  
Temporal Dynamics ◽  
Remote Sensing And Gis ◽  
Cultivated Land ◽  
Landsat Images ◽  
Systèmes D’Information Géographique ◽  
Spatio Temporal ◽  
Systèmes D’Information

L’objectif de cette étude est d’établir à partir de la télédétection et des SIG, la dynamique spatio-temporelle des terres de cultures et d’explorer les futurs possibles de l’occupation du sol dans trois communes rurales de la région de Thiès (Fandène, Notto Diobass et Taiba Ndiaye). Une classification multidate des images landsat (1988, 2002 et 2014) a permis de quantifier les changements d’occupation des terres. Les résultats montrent que les zones de culture de Fandène sont passées entre 1988 et 2014 de 62% à 52% de la superficie totale de la commune. A l’opposée la commune de Taiba Ndiaye connait une expansion des zones de culture entre ces deux dates. Les changements enregistrés à Notto sont négligeables. Les simulations, faites sur la base des probabilités pour que la valeur d’une cellule i reste inchangée ou prenne la valeur d’une autre cellule j à l’horizon 2035, révèlent que les terres de culture de Fandène ont 69% de probabilité d’évoluer vers d’autres classes d’occupation du sol. ABSTRACT The objective of this study is to quantify from remote sensing and GIS the spatio temporal dynamics of cultivated land and explore possible futures of land use in three rural municipalities of Thies (Fandene, Notto Diobass, and Taiba Ndiaye). A multidate classification Landsat images (1988, 2002 et 2014) was used to quantify change in land cover. The results show that between 1988 and 2014 Fandene cropping areas have passed from 62% to 52% of the total area. At the opposite the commune of Taiba Ndiaye has known an expansion of cropping areas between these two dates. Minor changes are noted in Notto district. Simulations carried out on the basis of probabilities for a unit i to stay in the same cell or to be converted to another unit j in 2035, reveals that the probability for a cultivated land unit to be transformed into a another land cover category is high in Fandene (69 %).

scholarly journals SATELLITE IMAGERY DRIVEN ASSESSMENT OF LAND USE LAND COVER, URBANIZATION AND SURFACE TEMPERATURE PATTERN DYNAMICS OVER TROPICAL MEGACITIES

2021 ◽  
Vol XLVI-4/W6-2021 ◽  
pp. 313-320
Author(s):  
S. Verma ◽  
S. Agrawal ◽  
K. Dutta
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Surface Temperature ◽  
Land Surface ◽  
Temperature Pattern ◽  
Land Use Land Cover ◽  
Landsat Images ◽  
Pattern Dynamics ◽  
Spatio Temporal ◽  
Supervised Image Classification

Abstract. In most of the developing nations, fast paced urbanisation is going on. This has changed the spatial patterns of Land Use Land Cover (LULC) and Land Surface Temperature (LST) over time. Continual studies are required in this context to know these phenomena more clearly. This study is carried out to analyse the spatio-temporal changes in LULC, urbanisation and LST in the metropolitan cities of India namely Delhi and Bengaluru. Landsat images of TM and OLI sensors are taken for the years 2001, 2010 and 2020. The LULC layer is obtained through supervised image classification. Concentric circles at the interval of 2 km are drawn from the centroid of the study areas which are used to compute Shannon's entropy through zonal analysis of the reclassified LULC layer. The thermal band of the Landsat is used for the computation of LST. The results of both the study areas revealed 1) decline in the open land, vegetation and water body; 2) rampant growth of built-up and urban area which become more compact over the years; and 3) spread of the higher LST zones.

Climatology of aerosols over the Caribbean islands: aerosol types, synoptic patterns and transport

2022 ◽  
Keyword(s):  
Rainy Season ◽  
Source Region ◽  
Temporal Distribution ◽  
Dry Season ◽  
Marine Aerosols ◽  
Western Atlantic ◽  
Synoptic Patterns ◽  
Caribbean Islands ◽  
Spatio Temporal ◽  
Aerosol Types

Abstract We present a climatological study of aerosols in four representative Caribbean islands based on daily mean values of aerosol optical properties for the period 2008- 2016, using the Aerosol Optical Depth (AOD) and Ångström Exponent (AE) to classify the dominant aerosol type. A climatological assessment of the spatio-temporal distribution of the main aerosol types, their links with synoptic patterns and the transport from different sources is provided. Maximum values of AOD occur in the rainy season, coinciding with the minimum in AE and an increased occurrence of dust, while the minimum of AOD occurs in the dry season, due to the predominance of marine aerosols. Marine and dust aerosol are more frequent in the easternmost islands and decrease westwards due to an increasing of continental and mixture dust aerosols. Therefore, the westernmost station displays the most heterogeneous composition of aerosols. Using a weather type classification, we identify a quantifiable influence of the atmospheric circulation in the distribution of Caribbean aerosols. However, they can occur under relatively weak and/or diverse synoptic patterns, typically involving transient systems and specific configurations of the Azores High that depend on the considered station. Backward trajectories indicate that dry-season marine aerosols and rainy-season dust are transported by air parcels travelling within the tropical easterly winds. The main source region for both types of aerosols is the subtropical eastern Atlantic, except for Cuba, where the largest contributor to dry-season marine aerosols is the subtropical western Atlantic. Different aerosol types follow similar pathways, suggesting a key role of emission sources in determining the spatio-temporal distribution of Caribbean aerosols.

scholarly journals Approach for Analysis of Land-Cover Changes and Their Impact on Flooding Regime

Quaternary ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 27 ◽  
Author(s):  
Badri Bhakta Shrestha
Keyword(s):  
Land Cover ◽  
The Philippines ◽  
Land Cover Changes ◽  
Flood Inundation ◽  
Flood Hazards ◽  
Distributed Hydrological Model ◽  
Landsat Images ◽  
The Future ◽  
Land Cover Map ◽  
Land Cover Maps

This study focused on the analysis of land-use/land-cover changes and their impact on flood runoff, flood hazards and inundation, focusing in the Pampanga River basin of the Philippines. The land-cover maps for the years 1996 and 2016 were generated using Landsat images, and the land cover changes were analyzed using TerrSet Geospatial Monitoring and Modeling System (TGMMS). Based on an empirical approach and considering variable factors, the land-cover maps for the future were predicted using Land Change Modeler (LCM). After preparation of land-cover maps for past and future years, flood characteristics were analyzed using a distributed hydrological model named the rainfall runoff inundation (RRI) model with a land-cover map for different years. The impacts of land cover changes on flood runoff, flood volume and flood inundation were analyzed for 50- and 100-year floods. The results show that flood runoff, flood inundation volume and flood extent areas may increase in the future due to land-cover change in the basin.

scholarly journals Spatio-Temporal Distribution of Chlorophyll-a Using Multitemporal Landsat Image and Ground Check in Segara Anakan Lagoon

2018 ◽  
Vol 47 ◽  
pp. 03007 ◽  
Author(s):  
Rose Dewi ◽  
Muhammad Zainuri ◽  
Sutrisno Anggoro ◽  
Tjahjo Winanto ◽  
Hadi Endrawati
Keyword(s):  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Satellite Image ◽  
Temporal Distribution ◽  
Image Data ◽  
Field Measurements ◽  
Anthropogenic Factors ◽  
Landsat Images ◽  
Spatio Temporal ◽  
Segara Anakan Lagoon

Segara Anakan lagoon (SAL) is a dynamic estuary, downstream of several rivers in Citanduy watershed, humid tropical climate and influenced monsoon, conditions that cause waters to fluctuate. There are influence of natural and anthropogenic factors that impact on the increase of aquatic organic matter, as phytoplankton indicator biota able to show its tolerance characterized by fluctuation of chlorophyll content a. The purpose of this research is to know the spatio-temporal distribution of chlorophyll- a SAL region. The chlorophyll- a measurement method uses multitemporal landsat images and field measurements. The temporal approach (time series) during 2016 refers to the monsoon wind pattern and spatially on seven different stations of ecological characteristics. Data processing using ER Mapper 7.0 software and the preparation of thematic data with Arc GIS software. Testing data accuracy using regression analysis. The results of chlorophyll-a recording of landsat images ranged from 3,213 - 3,703 (mg / m3) and field measurements from 0.01 to 5.06 (mg / m3). Temporally transitional seasons and on spatial approaches, stations with anthropogenic characteristics have the highest chlorophyll content. The condition is supported by the accumulation of aquatic organic materials, high rainfall and upwelling phenomenon. Test of accuracy pertained high, shown with value of r = 0,94 at equation y = -30.07x2 + 217.0x - 387.0, R2 = 0.894 with regression characteristic is polynomial. The high accuracy value in the equation, shows that the SAL area algorithm can be applied to obtain chlorophyll content data in the field in the previous year with the support of satellite image data in that year.

Land Cover Changes and Urban Expansion in Chongqing, China: A Study Based on Remote Sensing Images

2021 ◽  
pp. 097542532199803
Author(s):  
Xuan Sun ◽  
Yunxia Liu ◽  
Tao Sun ◽  
Sihang Yu ◽  
Chenguang Li ◽  
...  
Keyword(s):  
Land Cover ◽  
Spatial Clustering ◽  
Urban Expansion ◽  
Land Cover Changes ◽  
Remote Sensing Images ◽  
Urbanization Process ◽  
Landsat Images ◽  
Local Topography ◽  
Spatio Temporal ◽  
The City

China has experienced an unprecedented rate of urbanization in recent decades. As a city with strong political and economic influences in the southwest of China, Chongqing is a typical example of rapidurban development in this period of time. To study the land cover changes and urban expansion of Chongqing, Landsat images from 1999 to 2018 were selected, processed, and quantitatively analysed The results showed that the built-up area of the city had increased tremendously during these years, yet vegetation still accounted for the vast majority of the city’s land area. Restricted by the local topography including mountains and hills and infrastructure constructions, the urbanization process that occurred in central Chongqing actually showed a dominant expansion direction, an obvious spatial clustering tendency, and significant spatio-temporal differences among various regions.

scholarly journals Spatio Temporal Distribution of Anthrax in Sulawesi 2015-2018

2020 ◽  
pp. 7-13
Author(s):  
Titis Furi Djatmikowati ◽  
Dini Wahyu Yudianingtyas ◽  
Haeriah Haeriah
Keyword(s):  
Information System ◽  
Spatial Distribution ◽  
Geographic Information System ◽  
Rainy Season ◽  
Endemic Area ◽  
Temporal Distribution ◽  
Risk Area ◽  
Epidemic Curve ◽  
South Sulawesi ◽  
Spatio Temporal

Three among five Provinces (South Sulawesi, West Sulawesi and Gorontalo) in Sulawesi island, Indonesia are endemic area of anthrax disease. The aim of this study was to describe the dynamic of anthrax during 2015-2018 and identified risk area in Sulawesi. We determined case of anthrax disease from passive-active surveillance data Disease Investigation Center Maros (DIC Maros) during 2015-2018. Spatial distribution describe by mapping using Quantum Geographic Information System (QGIS), the temporal distribution describe using epidemic curve and we calculated the proportion of animal infected of anthrax. There were thirty-three cases of anthrax spreaded into three Provinces in Sulawesi, there were twenty one cases in South Sulawesi (63.6%), nine cases in Gorontalo (27.3%) and three cases West Sulawesi (9.1%). There were eleven cases (33.3%) in 2015, fifteen cases (45.5%) in 2016, four cases (12%) in 2017 and three cases (6%) in 2018. Anthrax occured respectively in dry season in South Sulawesi and Gorontalo, different with West Sulawesi anthrax occured in rainy season. The proportion of the animal infected were 87% in cattle, 7% in horse, 3% goat and 3% in deer. Vaccination of anthrax in South Sulawesi and Gorontalo should be conducted in May; in Polewali Mandar, West Sulawesi in Februari.

Sign in / Sign up

Export Citation Format

Share Document