Burnt area estimation for the year 2005 in Borneo using multi-resolution satellite imagery

2007 ◽  
Vol 16 (1) ◽  
pp. 45 ◽  
Author(s):  
Jukka Miettinen ◽  
Andreas Langner ◽  
Florian Siegert
Keyword(s):  
Satellite Imagery ◽  
Large Scale ◽  
Agricultural Land ◽  
Fire Detection ◽  
Small Scale ◽  
Burnt Area ◽  
Active Fire ◽  
Medium Resolution ◽  
Significant Difference ◽  
Degraded Ecosystems

Humid tropical South-East Asia suffers significant yearly biomass burning. This paper evaluates and compares the results of medium-resolution (MODIS) burnt area mapping and hotspot-based assessment of fire affected areas in Borneo in 2005, using field observations and high resolution Landsat ETM+ data as reference. Based on burnt area mapping, over 600 000 ha burnt in large-scale vegetation fires. Approximately 90% of this burning took place in degraded ecosystems and was related to agricultural land clearing activities or logged over forests. The estimation based on active fire detection (hotspots) resulted in a total burnt area of more than 1.1 million hectares. The reason for this significant difference was that small scale shifting cultivation fires could not be detected in MODIS images. These results indicate that a combination of both methods is required to reliably assess burnt areas in Borneo using medium-resolution MODIS satellite imagery.

scholarly journals Fractal properties of forest fires in Amazonia as a basis for modelling pan-tropical burnt area

2014 ◽  
Vol 11 (6) ◽  
pp. 1449-1459 ◽  
Author(s):  
I. N. Fletcher ◽  
L. E. O. C. Aragão ◽  
A. Lima ◽  
Y. Shimabukuro ◽  
P. Friedlingstein
Keyword(s):  
Forest Fires ◽  
Large Scale ◽  
Fire Spread ◽  
Small Scale ◽  
Burnt Area ◽  
Active Fire ◽  
Fractal Properties ◽  
Dynamic Global Vegetation Models ◽  
Vegetation Models ◽  
Global Vegetation

Abstract. Current methods for modelling burnt area in dynamic global vegetation models (DGVMs) involve complex fire spread calculations, which rely on many inputs, including fuel characteristics, wind speed and countless parameters. They are therefore susceptible to large uncertainties through error propagation, but undeniably useful for modelling specific, small-scale burns. Using observed fractal distributions of fire scars in Brazilian Amazonia in 2005, we propose an alternative burnt area model for tropical forests, with fire counts as sole input and few parameters. This model is intended for predicting large-scale burnt area rather than looking at individual fire events. A simple parameterization of a tapered fractal distribution is calibrated at multiple spatial resolutions using a satellite-derived burnt area map. The model is capable of accurately reproducing the total area burnt (16 387 km2) and its spatial distribution. When tested pan-tropically using the MODIS MCD14ML active fire product, the model accurately predicts temporal and spatial fire trends, but the magnitude of the differences between these estimates and the GFED3.1 burnt area products varies per continent.

Relative Efficiency of Ancillary and Small Scale Units

1978 ◽  
Vol 3 (4) ◽  
pp. 279-284
Author(s):  
K.R. Shaligram
Keyword(s):  
Small Firms ◽  
Large Scale ◽  
Small Scale ◽  
Underlying Assumption ◽  
Significant Difference ◽  
End Products ◽  
Policy Measures ◽  
The Mean ◽  
Small Manufacturers ◽  
Better Than

Ancillary units are small firms manufacturing and supplying intermediate goods, typically to large firms. Several policy measures are under consideration to raise the output of the ancillary industry to the level of 15 per cent of the value of output of the large scale industry by 1985. The underlying assumption appears to be that the ancillary status enhances the prospect for the viability of the small firm. This paper examines whether ancillary units perform better than small scale units (small manufacturers of end products) under the conditions prevailing in India. The findings reveal no significant difference in the mean performance of the two classes of small firms. It also draws implications for policymakers and management from the findings.

Validation studies of EUMETSAT's active fire monitoring product over Turkey

2009 ◽  
Vol 18 (5) ◽  
pp. 517 ◽  
Author(s):  
Ahmet Emre Tekeli ◽  
İbrahim Sönmez ◽  
Erdem Erdi ◽  
Fatih Demir
Keyword(s):  
Temporal Distribution ◽  
Fire Detection ◽  
Burnt Area ◽  
Pixel Resolution ◽  
European Organization ◽  
Fire Monitoring ◽  
In Situ Data ◽  
Active Fire ◽  
Spatio Temporal

Fire detection and monitoring are challenging tasks that require continuous, early and quick responses that are as accurate as possible. Satellite-based systems are indispensable tools for operational and research agencies to accomplish such a demanding task. The frequent and continuous imagery capability of the geostationary satellites makes them the best candidate for early fire detection systems. The main purpose of the present paper is to analyze the spatio-temporal distribution of active fire monitoring (FIR) products of the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT)’s Meteosat Second Generation (MSG) satellite with in situ data for the summer of 2006 over Turkey. In situ data were obtained from the fire reports of the Ministry of Environment and Forestry, Turkey. The main shortcomings of the MSG active fire monitoring product validation arise from the pixel resolution and fire coverage, which are examined on the basis of some recent examples. The diurnal cycle of active fires identified well with the product. The burnt area effects on the accuracy of hit ratios were also analyzed. It is seen that the possibility for the fire to be detected by MSG increases with increasing burnt area. Even with the present anomalies, remote sensing may provide a consistent systematic way of monitoring fires, removing human biases and enabling a long-term dataset, which has been a goal of Global Observation of Forest and Land Cover Dynamics (GOFC/GOLD).

Scale-dependent patterns of deforestation in the Brazilian Amazon

2006 ◽  
Vol 33 (3) ◽  
pp. 203-211 ◽  
Author(s):  
ROBERT M. EWERS ◽  
WILLIAM F. LAURANCE
Keyword(s):  
Large Scale ◽  
Amazon Basin ◽  
Agricultural Land ◽  
Brazilian Amazon ◽  
Small Scale ◽  
Land Uses ◽  
Tropical Landscapes ◽  
Isolation Effects ◽  
Formal Test ◽  
Geographical Locations

Tropical forests of the Amazon Basin are being rapidly converted to agricultural land uses and fallow land, resulting in accelerating rates of forest loss in one of the world's most biodiverse ecoregions. This process has been extensively described and modelled, but as yet there has been no formal test of how the spatial patterns of deforested and fragmented areas change with the spatial scale of forest clearings. It was hypothesised that different land-use practices are driving small and large clearings, with small-scale cultivators often creating small, irregularly shaped clearings and large-scale ranchers and soy farmers creating larger, more regular-shaped clearings. To quantitatively test this hypothesis, Mandelbrot's theory of fractals was applied to deforested areas in the Brazilian Amazon to test for scale-invariance in deforestation patterns. The spatial pattern of deforestation differed between small and large clearings, with the former creating more complex landscapes and with a threshold occurring at c. 1200 ha in area. As a consequence, the sizes and shapes of forest clearings, and hence the relative vulnerability of the remaining forest to edge, area and isolation effects, may differ systematically between landscapes with different deforestation drivers. Further tests of this hypothesis are needed to assess its efficacy in other tropical landscapes and geographical locations.

Comparison of shear strength of sand backfills measured in small-scale and large-scale direct shear tests

2008 ◽  
Vol 45 (9) ◽  
pp. 1224-1236 ◽  
Author(s):  
Christopher A. Bareither ◽  
Craig H. Benson ◽  
Tuncer B. Edil
Keyword(s):  
Large Scale ◽  
Triaxial Compression ◽  
Particle Diameter ◽  
Small Scale ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Failure Envelopes ◽  
Significant Difference ◽  
Backfill Materials

Direct shear tests were conducted on 30 sand backfill materials having gravel contents ranging from 0% to 30% in a 64 mm square small-scale direct shear (SSDS) box and a 305 mm square large-scale direct shear (LSDS) box. The objectives were to compare the shearing behavior of a broad range of natural sand backfill materials tested in SSDS and LSDS and to determine if the same friction angle (φ′) is obtained in SSDS and LSDS when the natural backfill material contains gravel. Triaxial compression (TC) tests were also conducted on four of the backfill materials for comparison with the SSDS and LSDS tests. Specimens tested in SSDS and TC included only material passing the No. 4 sieve (P4). Test specimens in LSDS included the P4 material as well as material retained on the No. 4 sieve (R4), to a maximum particle diameter of 25.4 mm. Friction angles corresponding to peak strength (φ′) measured in SSDS and LSDS differed by no more than 4° for a given sand backfill, and in most cases were within 2°. The friction angles also were unaffected by removal of the R4 material. Repeatability tests showed that statistically similar failure envelopes (p-value = 0.98) are obtained in SSDS and LSDS, and that highly repeatable friction angles (φ′) are obtained using the SSDS (φ′ ± 0.25°) and the LSDS (φ′ ± 0.45°) methods. No statistically significant difference was found among the failure envelopes measured in SSDS, LSDS, and TC, suggesting that φ′ for clean sand backfill with less than 30% gravel can be measured with similar accuracy using any of the three test methods.

scholarly journals Active fire detection in Landsat-8 imagery: A large-scale dataset and a deep-learning study

2021 ◽  
Vol 178 ◽  
pp. 171-186
Author(s):  
Gabriel Henrique de Almeida Pereira ◽  
Andre Minoro Fusioka ◽  
Bogdan Tomoyuki Nassu ◽  
Rodrigo Minetto
Keyword(s):  
Deep Learning ◽  
Large Scale ◽  
Fire Detection ◽  
Landsat 8 ◽  
Learning Study ◽  
Active Fire ◽  
Large Scale Dataset

scholarly journals ENGINEERING GEOLOGICAL AND GEOTECHNICAL INVESTIGATION OF LANDSLIDE EVENTS IN WILDFIRE AFFECTED AREAS OF ILIA PREFECTURE, WESTERN GREECE

2017 ◽  
Vol 43 (3) ◽  
pp. 1138 ◽  
Author(s):  
N. Depountis ◽  
S. Lainas ◽  
D. Pyrgakis ◽  
N. Sabatakakis ◽  
G. Koukis
Keyword(s):  
Large Scale ◽  
Agricultural Land ◽  
Site Investigation ◽  
Geological Mapping ◽  
Small Scale ◽  
Geotechnical Investigation ◽  
Protection Measures ◽  
Socio Economic Impact ◽  
Geological Formations ◽  
Western Greece

In August 2007 Ilia Prefecture suffered one of the most devastating wildfires that have ever happened on European level. Approximately 870km2 , mainly forest and agricultural land, were lost, more than 60 people were killed, hundreds were injured and many villages suffered extensive damage. Heavy rainfall and human activities, favoured by the loss of vegetation and the overall susceptibility of geological formations in landsliding, induced the manifestation or reactivation of various scale landslide phenomena. In order to investigate and mitigate the problem University of Patras was commissioned by the Region of Western Greece to undertake an Engineering Geological and Geotechnical investigation. Site investigation accomplished in seven municipalities focusing on several landslide events with serious socio-economic impact and as a result many small scale cases were identified. In each one of these cases large scale engineering geological mapping was conducted and remedial and protection measures were designed.

Comparison of Measured Transient Ceiling Jet Temperature and Velocity Profiles in the Presence of an Upper Layer With Predictions by LAVENT Computer Fire Model

2003 ◽  
Author(s):  
Vahid Motevalli ◽  
Siamak Riahi
Keyword(s):  
Experimental Data ◽  
Large Scale ◽  
Fire Detection ◽  
Peak Temperature ◽  
Small Scale ◽  
Radiative Loss ◽  
Fire Model ◽  
Ceiling Height ◽  
And Performance ◽  
Upper Layer Temperature

Development of an upper layer in enclosure fires has a significant effect on the characteristics of the ceiling jet and a direct influence on the placement and performance of fire detection/suppression devices. Detailed transient measurement of ceiling jet velocity and temperature profiles within an upper layer for small-scale fires (2.0 kW and ceiling height of 1 m) are used to analyze the predictions produced by the LAVENT computer fire model. While the model predictions have been compared with large-scale experimental results with fires as large as 33 MW and ceiling height of up to 22m, the large-scale measurements do not have high special resolution and the present work offers a more thorough analysis of the model prediction. Various radiative losses (10–25%) were used to produce predictions that matched the experimental data. Comparison of the small-scale experimental data with the predictions from LAVENT shows that the model, which uses unconfined ceiling jet correlations, does not capture the ceiling jet profile well and over predicts the upper layer temperature during the development of the layer. The peak temperature prediction requires a different radiative loss factor than that which matches the upper layer temperature. In general, the peak temperature measurements are within 10% of the measured value. The velocity is generally over predicted since the retardation of the jet momentum by the upper layer does not seem to be modeled accurately.

scholarly journals MODIS Reflectance and Active Fire Data for Burn Mapping in Colombia

2011 ◽  
Vol 15 (10) ◽  
pp. 1-17 ◽  
Author(s):  
Silvia Merino-de-Miguel ◽  
Federico González-Alonso ◽  
Margarita Huesca ◽  
Dolors Armenteras ◽  
Carol Franco
Keyword(s):  
Terrestrial Ecosystem ◽  
Fire Detection ◽  
Cost Effective ◽  
Burned Area ◽  
Remotely Sensed Data ◽  
Burnt Area ◽  
Ecosystem Monitoring ◽  
Active Fire ◽  
Burned Area Mapping ◽  
Area Product

Abstract Satellite-based strategies for burned area mapping may rely on two types of remotely sensed data: postfire reflectance images and active fire detection. This study uses both methods in a synergistic way. In particular, burned area mapping is carried out using MCD43B4 [Moderate Resolution Imaging Spectrometer (MODIS); Terra + Aqua nadir bidirectional reflectance distribution function (BRDF); adjusted reflectance 16-day L3 global 1-km sinusoidal grid V005 (SIN)] postfire datasets and MODIS active fire products. The developed methodology was tested in Colombia, an area not covered by any known MODIS ground antenna, using data from 2004. The resulting burned area map was validated using a high-spatial-resolution Landsat-7 Enhanced Thematic Mapper Plus (ETM+) image and compared to two global burned area products: L3JRC (terrestrial ecosystem monitoring global burnt area product) and MCD45A1 (MODIS Terra + Aqua burned area monthly global 500-m SIN grid V005). The results showed that this method would be of great interest at regional to national scales because it proved to be quick, accurate, and cost effective.

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