EKOSAT-IR-Ecology-related earth observation and hot spot detection

Abstract

The initial EKOSAT (ELOP-KARI-OHB-Satellite) mission, planned to be launched as in-orbit demonstrator of the Multi-Spectral Remote-sensing System (MSRS), is enhanced by the space-proven Hot-Spot-Recognition System (HSRS) from DLR. HSRS is currently demonstrating its advanced High-Temperature Event detection and analysis capabilities on the German Bi-spectral InfraRed Detection (BIRD) satellite. MSRS, developed by OHB and ELOP, provides high-resolution super-spectral data (VIS/NIR) for ecological applications. Joint operation of MSRS and HSRS will deliver for the first time simultaneously high-resolution super spectral and hot-spot data of hazard events. A feasibility study based on the existing KOMPSAT-1 flight spare model from KARI as spacecraft bus shows that EKOSAT-IR will facilitate a fast in-orbit deployment of MSRS and HSRS at a comparably low-cost. Based mainly on existing ground infrastructure, EKOSAT-IR will demonstrate and deliver new super-spectral and infrared Earth observation products for Earth Watch and GMES objectives as well as for upcoming commercial markets.

Introduction

Earth observation satellites launched over the last 30 years have made important contributions to the understanding of our world and the various elements that it comprises. It is the “bird's eye perspective” combined with a high temporal revisit time allowing a fast and border-less overview in a wide spectral range that makes satellite remote sensing an attractive data source for environmental information.

Over the past 20–30 years, multispectral remote sensing has mainly been carried out by “classical” existing multispectral systems like SPOT 1–3, the Landsat series, IRS-1C and $-1$D with 3 or 4 spectral bands with a medium spatial resolution of 20–30 m. For future developments, two major trends can be identified:

• Available and planned very high-resolution multi-spectral systems such as IKONOS-2, Orbview 3 and Quickbird also with 3-4 spectral bands but at a very high (1 m) spatial resolution.

• Available and planned systems carrying hyperspectral sensors like EO1, NEMO and HYPSEO providing spatial resolutions of 20–30m but at a large number of spectral bands ($\sim$200) across the electromagnetic spectrum.

In particular, vegetation-related and ecological applications require remote sensing data with specific spectral information at a high spatial resolution ($<10$ m), that the present systems are not able to deliver. To fill this gap, the Multi-Spectral Remote-sensing System (MSRS) was developed on a user-driven approach by OHB-System AG and Electro-Optic Industries Ltd. (ELOP) providing 12 dedicated spectral bands with 5 m spatial resolution.

Wildfires annually affect several hundred million hectares of forest and other vegetations of the world. In some ecosystems, fire plays an ecologically significant role in biogeochemical cycles and disturbance dynamics. In other ecosystems, fire may lead to the destruction of forests or to long-term site degradation. In most areas of the world wildfires burning under extreme weather conditions will have detrimental impacts on economies, human health and safety, with consequences which are comparable to the severity of other natural hazards.

Vegetation fires and volcano eruptions affect the chemistry of the atmosphere, alter the radiation budget of the Earth, and contribute to the green-house process through gases such as ${\mathrm{CO}}_2,{\mathrm{CH}}_4$, and ${\mathrm{NO}}_2$. The combustion gases ${\mathrm{CH}}_4$, CO, and NO play an important role in the formation of tropospheric ${\mathrm{O}}_3$. About 60% of the global emissions of ${\mathrm{CO}}_2$ and other green-house gases are related to anthropogenic fossil fuel burning and cement production, i.e. well-known processes. The remaining $\sim$40% of the green-house gas emissions—together with a huge amount of aerosols—are generated by biomass burning, volcanic activities and coal seam burning, processes which are still purely understood and quantified on global scale.

Current space-borne sensor systems are used to generate products of fire susceptibility evaluating time-series of vegetation state data, occurrence and coarse location of active fires, as well as smoke and burnt areas. However, existing and planned operational space-borne sensors show serious limitations such as

• channel saturation leading to reduced high-temperature event discrimination,

• spatial resolution worse than 1 km.

With the launch of the Bi-Spectral-Infrared-Detection (BIRD) micro-satellite mission in October 2001, the Hot-Spot-Recognition-System (HSRS) is being tested in space. HSRS features a new generation of infrared sensors with an adaptive radiometric dynamic range in order to detect and assess hot-spot events like vegetation fires, volcanic activities, burning oil wells and coal seams.