Monitoring of Forest Fires And Oil Pollution from Space
Soo Chin Liew, Leong Keong Kwoh,Oo Kaw Lim Jinguan Lu, Karunakaran Padmanabhan and Hock Lim
Center For Remote Imaging, Sensing And Processing (CRISP)
National University of Singapore,
Lower Kent Road, Singapore 119260
Tel : (65) 8745069 ; Fax : (65) 7757717,
E-mail: phyliew@nus.edu.sg
Abstract
High resolution remote sensing from the SPOT, ERS and RADARSAT satellites are being used to routinely monitor land/forest fires and ocean oil pollution in the Southeast Asian region. Burnt scar maps have been generated from missions of SPOT images. In could-covered area. Interfermetric SAR from ERS-1/2 tandem mission are used to complement the optical imagery in assessing burnt areas. ERS and RADARSAT SAR images are useful in detection of oil slicks. A map showing the spatial distribution of oil slicks over Southeast Asian waters have been compiled.
Introduction
Forest fires and ocean oil pollution are two major concerns that affect many countries in Southeast Asia. The 1997/98 forest fires resulted in trans- boundary air pollution in the form of smoke have which has been reported to cause billons in economic loss to the region. The environment effects of forest fires include the loss of biodiversity, loss of forests as carbon sinks and greenhouse grass emission. Several major oil pollution events have also occurred in the region. In this paper we report on the research and monitoring of forest fires and ocean oil pollution using high resolution satellite imagery.
The Centre for remote Imaging Sensing and Processing (CRISP) at the National University of Singapore operates a satellite ground station for reception of images from remote sensing satellite. The reception circle of CRISP's ground station covers the whole of Southeast Asian region. The ground station is currently receiving data from the SPOT ERS and RADARSAT satellite. The high resolution images acquired by these satellite are being used in routine monitoring of forest fires and ocean oil pollution inn the region.
Forest Fires Monitoring
The AVHRR sensors on board the NOAA Polar Orbiting Satellite are conventionally used in monitoring land/forest fires. In particular, the 3.8 mm infrared (band 3) is used in hot spot detection [1,2,3]. The visible band (band1) and the near infrared band (band2) of the same sensors can provide information about the aerosols characteristics and distribution of the smoke have[4].fig. 1shows an AVHARR image acquired in 1 April 1998 over the Borneo island. Smoke plumes can be emerging from the northern coast and drifting to the northwest direction. Fig.2 shows a typical hot spots and smoke have distribution map derived from the AVHRR images. There are well-known limitations on the use of AVHRR images in fire monitoring. The resolution of the images is coarser than 1 km, hence the precise location of the fire spots cannot be determined. Band 3 of the sensor saturates at an effective temperature around 320 K.A pixel can be detected as a hot-spot pixel due to a small but intense fire anywhere within the 1-km
2 pixel or by a large extent of warm a land surface. Reflection false alarms radiation from high-albedo land surface, clouds or sea water can also produce false alarms in hot spot detection. Due to these limitations, AVHRR hotspot images tend to overestimate the burnt area but underestimate the number of fires.
Fig.1(left): AVHRR image (bands1,2,3 composite, shown here in greyscale)of Borneo on 1 April 1998.
Fig 2(right): Hot spots and smoke haze distribution map derived from AVHRR images on 26 March 1998.
Hotspots are deteced in East Kalimantan,Sabah and Brunei. (Issued by Meteorological Service Singapore)
CRISP has been commissioned by the Ministry of Environment, Singapore to perform daily fires monitoring over the Southeast Asian region, as a component of the ASEAN haze action plan. Spot images are used to detect smoke plumes, about scars and to establish the locations and extent of the fire affected areas. The processing system has been modified so that full-resolution images can be processed in almost real-tim. A report on the fires detected is pre[ared and transmited to the Ministry of Environment at the end of the day of image acquisition.
