Disasters

HyspIRI will be able to make telling contributions to quantifying the hazards presented by volcanoes and wildfires. The TIR instrument will make measurements of the energy emitted by Earth’s surface at 60 m resolution, at middle infrared wavelengths (approximately 4 micrometers), as well as seven spectral bands in the thermal infrared (8-12 micrometers). Targets that have high temperatures emit prodigious amounts of energy at 4 micrometers, making the identification of pixels that contain active lavas or vegetation fires relatively easy using the data that HyspIRI will provide. As this channel is being designed with a wide measurement range, the intensity of the thermal emission can also be accurately quantified, to determine where the most active lavas (or the most active fires) are to be found. It is the combination of high spatial resolution, high temporal resolution, and global day-and-night mapping, using a dedicated “hot-spot” detection waveband, that will make HyspIRI unique with respect to other earth observation missions in this regard.

An example of the role that HyspIRI will be able to make in disasters, is its role in forecasting which areas surrounding a volcano are at risk of inundation during an effusive lava flow forming eruption. After lava chemistry, the most important variable that influences how far a lava flow can extend from the vent is the volumetric effusion rate (the rate at which the lava comes out of the vent). If it is high the lava can flow further before it cools and solidifies. The data acquired by the HyspIRI will allow the effusion rate to be estimated every time a new image is acquired during an eruption (by day and night every five days). This measurement can then be used to drive numerical models that forecast how far the lava might flow, given that flux rate. If, the next time HyspIRI acquires an image, the flux rate is found to have changed, a new simulation can be run, which reflects how the hazard posed by the eruption is evolving. In this way, HyspIRI can be used to autonomously drive lava flow hazard simulations from space (using the effusion rate data is will provide) as well as calibrate the predictions (using the high spatial resolution images it acquires). The example below shows how this technique was successfully validated using Landsat data at Mount Etna, where the color plates show the predicted flow dimensions during the first two weeks of the 1991-1993 eruption, obtained by driving a flow prediction model using effusion rates extracted from Landsat TM images (the black polygons show the actual flow dimensions as observed in the field). HyspIRI will offer an enhanced flow hazard prediction capability, because its higher temporal resolution will allow us to better constrain short time scale fluctuations in the important effusion rate parameter.

HyspIRI will also be able to provide high resolution information about the location of hazardous volcanic ash clouds. When an eruption begins, and ash is injected into the atmosphere above a volcano, it is dispersed by gravity and the prevailing wind-field. Aircraft that fly through such a cloud are subject to serious risk. HyspIRI has seven wavebands in the thermal infrared, specially located to enhance our ability to discriminate volcanic ash clouds from non-hazardous meteorological clouds. Combined with the high spatial resolution of the sensor, this will allow for more accurate information about the location of ash clouds and how this changes during an eruption, in addition to allowing us to detect ash in the atmosphere at lower concentrations than is currently achievable. The following images show the ash cloud produced during the eruption of, Eyjafjallajökull, Iceland, that closed down much of the northern hemisphere’s airspace in May and June of 2010. The image on the left show the cloud as it was imaged by MODIS (1 km resolution); the image on the right, by ASTER (90 m resolution). HyspIRI will improve on the ASTER measurements; importantly, as a mapping mission, HyspIRI will acquire these kind of data on a routine basis during any eruption on Earth.