Eckehard Lorenz

Satellite and Ground Based Thermal Observation of the 2014 Effusive Eruption at Stromboli Volcano

As specifically designed platforms are still unavailable at this point in time, lava flows are usually monitored remotely with the use of meteorological satellites. Generally, meteorological satellites have a low spatial resolution, which leads to uncertain results. This paper presents the first long term satellite monitoring of active lava flows on Stromboli volcano (August–November 2014) at high spatial resolution (160 m) and relatively high temporal resolution (~3 days). These data were retrieved by the small satellite Technology Experiment Carrier-1 (TET-1), which was developed and built by the German Aerospace Center (DLR). The satellite instrument is dedicated to high temperature event monitoring. The satellite observations were accompanied by field observations conducted by thermal cameras. These provided short time lava flow dynamics and validation for satellite data. TET-1 retrieved 27 datasets over Stromboli during its effusive activity. Using the radiant density approach, TET-1 data were used to calibrate the MODVOLC data and estimate the time averaged lava discharge rate. With a mean output rate of 0.87 m3/s during the three-month-long eruption, we estimate the total erupted volume to be 7.4 × 106 m3.

HSRS: an infrared sensor for hot spot detection

The observation of high temperature events (HTE) is an important field of the remote sensing because of their influence on the global change of the environmental processes. Currently a small satellite BIRD (Bispectral Infrared Detection) dedicated to this task is under development in the German Aerospace Center. Considering the restrictions of an 80 kg satellite a bispectral infrared push broom scanner working in the Midwave and in the Thermal Infrared based on the latest technology of linear detector arrays was developed. The identical design for both infrared channels was realized to save resources and to guarantee the reliability. Because of the limited number of elements per line a subpixel detecting concept was chosen to estimate the parameters of the HTE with a reasonable ground resolution and swath wide. A special dual band optics and a compact sensor head design will ensure the required geometric stability. The subpixel measurement method for the hot spot detection requires a high detectivity and a large dynamic range. A special signal processing concept has been implemented at the sensor head controller. Recently the first airborne experiments were carried out together with a push broom scanner in the visible. During this experiments the sensor control, onboard signal processing and data transmission routines were tested.

BIRD detection and analysis of high-temperature events: first results

The primary mission objective of a new small Bi-spectral InfraRed Detection (BIRD) satellite, which was put in a 570 km circular sun-synchronous orbit on 22 October 2001, is detection and quantitative analysis of high-temperature events (HTE) like fires and volcanoes. A unique feature of the BIRD mid- and thermal infrared channels is a real-time adjustment of their integration time that allows a HTE observation without sensor saturation, preserving a good radiometric resolution of 0.1-0.2 K for pixels at normal temperatures. This makes it possible: (a) to improve false alarm rejection capability and (b) to estimate HTE temperature, area and radiative energy release. Due to a higher spatial resolution, BIRD can detect an order of magnitude smaller HTE than AVHRR and MODIS. The smallest verified fire that was detected in the BIRD data had an area of ~12 m2. The first BIRD HTE detection and analysis results are presented including bush fires in Australia, forest fires in Russia, coal seam fires in China, and a time-varying thermal activity at Etna.

Calibration of a bispectral infrared push-broom imager

In May 2001 was planned to launch the small satellite BIRD, but the launch was shifted to August/September 2001. The main payload is dedicated to the observation of high temperature events and consists mainly of a Bi-Spectral IR Push Broom Scanner and a Push Broom Imager in the Visible. Solid state detector arrays with adaptive high dynamic front end electronics and advanced digital signal processing capabilities are the key element of IR imaging devices. With respect to the main mission objectives besides the high radiometric requirements to the detectors their mutual geometrical alignment is essential. The main problem of the radiometric calibration is the required high dynamic range which makes necessary to consider the non linear characteristic of the detector elements. On the other hand the application of special bi-spectral methods requests a carefully geometrical calibration. Besides the alignment of the different spectral channels the knowledge of the PSF is necessary. The laboratory radiometric and geometrical calibration procedures are described in this paper.

The GOFC-GOLD Fire Mapping and Monitoring Theme: Assessment and Strategic Plans

The objectives of the fire mapping and monitoring theme of the global observation of forest and landcover dynamics (GOFC-GOLD) program are to refine and articulate the international requirements for fire related observations, to increase access to and make the best possible use of existing and future observing systems for fire management, policy decision-making and global change research and to ensure the provision of long-term, systematic satellite observations necessary for the production of the full suite of recommended fire products. The GOFC-GOLD Fire Implementation Team also fostered the development of regional networks of data providers and users to capture regional specific information needs and priorities. This chapter discusses specific goals of the program related to pre-fire evaluation, fire observations and post-fire assessment, and the implementation status of corresponding activities. Examples of contributory programs from US agencies are also presented.

Detection, monitoring, and quantitative analysis of wildfires with the BIRD satellite

Increasing concern about environment and interest to avoid losses led to growing demands on space borne fire detection, monitoring and quantitative parameter estimation of wildfires. The global change research community intends to quantify the amount of gaseous and particulate matter emitted from vegetation fires, peat fires and coal seam fires. The DLR Institute of Space Sensor Technology and Planetary Exploration (Berlin-Adlershof) developed a small satellite called BIRD (Bi-spectral Infrared Detection) which carries a sensor package specially designed for fire detection. BIRD was launched as a piggy-back satellite on October 22, 2001 with ISRO’s Polar Satellite Launch Vehicle (PSLV). It is circling the Earth on a polar and sun-synchronous orbit at an altitude of 572 km and it is providing unique data for detailed analysis of high temperature events on Earth surface. The BIRD sensor package is dedicated for high resolution and reliable fire recognition. Active fire analysis is possible in the sub-pixel domain. The leading channel for fire detection and monitoring is the MIR channel at 3.8 μm. The rejection of false alarms is based on procedures using MIR/NIR (Middle Infra Red/Near Infra Red) and MIR/TIR (Middle Infra Red/Thermal Infra Red) radiance ratio thresholds. Unique results of BIRD wildfire detection and analysis over fire prone regions in Australia and Asia will be presented. BIRD successfully demonstrates innovative fire recognition technology for small satellites which permit to retrieve quantitative characteristics of active burning wildfires, such as the equivalent fire temperature, fire area, radiative energy release, fire front length and fire front strength.

Design and analysis of a small bispectral infrared push broom scanner for hot spot recognition

A small bispectral infrared detection (BIRD) push broom scanner for a small satellite emission is described, which is dedicated to the detection and analysis of high temperature events (HTE). Current operating and planned satellite sensors are not designed for high temperature event observation and therefore show some serious drawbacks such as saturation of the IR channels for target temperatures higher than 50 degrees Celsius, low spatial resolution in case of daily coverage, low coverage of spatially high resolving systems, or not adequate IR channels. The BIRD instrumentation is a first attempt to overcome these disadvantages. For this purpose two infrared line scanners (3.4 - 4.2 micrometer and 8.5 - 9.3 micrometer) are combined with a wide angle stereo scanner (WAOSS) in the visible. Because of the limited resources of a small satellite the design of all instruments is based on the usage of staring focal plane arrays. To observe HTE directly the covered sounding area should be as large as possible whereas at first glance the ground resolution of the sensor should be in order of some 10 m. These demands are in contradiction with the number of the infrared detector array elements currently available. For this reason methods of subpixel target detection and analysis have to be used. According to this concept a combination of the data from at least to radiometric high sensitive infrared sensor channels is used to compensate the lack of high ground resolution. Adding to the infrared cameras a suitable CCD-line scanner for a pre-classification with a higher ground resolution, a marked improvement can be achieved.

MERTIS: understanding Mercury's surface composition from mid-infrared spectroscopy

The Mercury Radiometer and Thermal Infrared Imaging Spectrometer MERTIS on the joint ESA-JAXA mission BepiColombo to Mercury is combining a spectrometer using an uncooled microbolometer in a pushbroom mode with a highly miniaturized radiometer. A full development model of MERTIS is now available. So, after three flybys of Mercury by the MESSENGER mission and with the Planetary Emissivity Laboratory at DLR in Berlin that can routinely obtain infrared emission spectra at high temperatures it is a good time to review the MERTIS science requirements and the performance in perspective of our new knowledge of Mercury.

Detection and characterization of low temperature peat fires during the 2015 fire catastrophe in indonesia using a new high-sensitivity fire monitoring satellite sensor (FireBird)

Vast and disastrous fires occurred on Borneo during the 2015 dry season, pushing Indonesia into the top five carbon emitting countries. The region was affected by a very strong El Niño-Southern Oscillation (ENSO) climate phenomenon, on par with the last severe event in 1997/98. Fire dynamics in Central Kalimantan were investigated using an innovative sensor offering higher sensitivity to a wider range of fire intensities at a finer spatial resolution (160 m) than heretofore available. The sensor is onboard the TET-1 satellite, part of the German Aerospace Center (DLR) FireBird mission. TET-1 images (acquired every 2–3 days) from the middle infrared were used to detect fires continuously burning for almost three weeks in the protected peatlands of Sebangau National Park as well as surrounding areas with active logging and oil palm concessions. TET-1 detection capabilities were compared with MODIS active fire detection and Landsat burned area algorithms. Fire dynamics, including fire front propagation speed and area burned, were investigated. We show that TET-1 has improved detection capabilities over MODIS in monitoring low-intensity peatland fire fronts through thick smoke and haze. Analysis of fire dynamics revealed that the largest burned areas resulted from fire front lines started from multiple locations, and the highest propagation speeds were in excess of 500 m/day (all over peat > 2m deep). Fires were found to occur most often in concessions that contained drainage infrastructure but were not cleared prior to the fire season. Benefits of implementing this sensor system to improve current fire management techniques are discussed. Near real-time fire detection together with enhanced fire behavior monitoring capabilities would not only improve firefighting efforts, but also benefit analysis of fire impact on tropical peatlands, greenhouse gas emission estimations as well as mitigation measures to reduce severe fire events in the future.

Advanced sensors for surveying and mapping

During the last years the department of Optical Information Systems of the German Aerospace Center (DLR) developed a considerable number of imaging sensor systems for a wide field of applications. Systems with a high geometric and radiometric resolution in dedicated spectral ranges of the electromagnetic spectrum were provided by developing and applying cutting edge technologies. Designed for photogrammetry and remote sensing, such systems play an important role for security and defence tasks. Complete system solutions were implemented considering theoretical framework, hardware design and deployment, overall system tests, calibration, sensor operation and data processing. Outstanding results were achieved with the airborne digital sensor ADS40 and the micro satellite BIRD and its infrared camera payload. Future activities will focus on intelligent cameras and sensor webs. The huge amount of data will force the issue of thematic multi-sensor data processing which is to be implemented in real time near the sensor. In dependence on well defined tasks, combinations of several sensors with special properties will be placed on spaceborne, airborne or terrestrial platforms. The paper gives an overview about finished and current projects and strategic goals.