Sunday, July 13, 2008
Today's Earth check-up
MIRAVI: the Earth live
Have you ever wanted to track natural events in progress, such as fires, floods and volcanic eruptions, or simply explore the planet through the eyes of a satellite? ESA has created a website, MIRAVI, which gives access to the most recently acquired images from the world’s largest Earth Observation satellite, Envisat.
MIRAVI, short for MERIS Images RApid VIsualisation, tracks Envisat around the globe, generates images from the raw data collected by Envisat’s optical instrument, MERIS, and provides them online within two hours.
The annual Antarctic ozone hole mapped for us by satellites is a grim symbol of our atmosphere's fragile complexity: supposedly harmless chemicals emitted by spray cans ravaged the layer of stratospheric ozone that protects all life on Earth from deadly ultraviolet radiation.
ESA satellites have been maintaining a regular census of global stratospheric ozone levels since 1995, mapping ozone holes as they appear. Now you can access near-real time global ozone fields for today and obtain forecasts for the week ahead.
Ozone forecasts »
UV radiation forecasts
The intensity of UV radiation that reaches Earth is directly related to the ozone concentration in the atmosphere, which acts as a sun filter and protects us from harsh UV rays. Excessive UV radiation increases the risk of skin cancer, cataracts and weakened immune systems and also affects the health of fauna and flora.
To combat these threats, there is a need to know UV levels and forecasts. By localising ozone depletion and tracking its changes, Envisat enables the rapid estimation of UV radiation as well as providing forecasting.
UV Radiation »
Sea surface temperature map acquired on 24 May 2006
The temperature of the surface of the ocean is an important physical property that strongly influences the transfer of heat energy, momentum, water vapour and gases between the ocean and the atmosphere.
As part of ESA’s Medspiration project, you can access the most detailed ever heat map of all 2 965 500 square kilometres of the Mediterranean, the world's largest inland sea, to obtain daily sea surface temperatures.
World Fire Atlas (WFA)
More than 50 million hectares of forest are burnt annually, and these fires have a significant impact on global atmospheric pollution, with biomass burning contributing to the global budgets of greenhouse gases, like carbon dioxide.
For a decade now, ESA satellites have been continuously surveying fires burning across the Earth’s surface. Worldwide fire maps based on this data are now available online in near-real time through ESA's ATSR World Fire Atlas. In addition to maps, the time, date, longitude and latitude of the hot spots are provided.
World Fire Atlas »
NRT swell system (Pacific Ocean)
Storm swells – a succession of large, long waves – are surprise factors that can have deadly consequences when they break on the shoreline. As they are generally preceded by calm water, it is often impossible to visually detect their arrival from shore.
Using the Advanced Synthetic Aperture Radar (ASAR) instrument aboard Envisat, scientists are locating and tracking swells in the Pacific, Atlantic and Indian Oceans in near real time. In the near future, both the arrival and intensity of the swells will be systematically predicted.
Pacific ocean »
Atlantic ocean »
Indian ocean »
EO satellite orbits
Ever wonder where your favourite ESA Earth observation satellites are, right now? Now that curiosity can be satisfied thanks to ESA’s Satellites in Orbits website. The Earth Observation Orbits site displays real-time information and animations about the orbital tracks and current locations of ESA’s satellites, providing a unique perspective on the Earth as if you were ‘standing’ thousands of kilometres high in space and looking down on it. You can alter the time, rotate the view, zoom in and out and learn more about the various satellites and their missions.
EO satellite orbits »
Last update: 14 February 2008
• MIRAVI (http://www.esa.int/miravi)
• Ozone forecasts (http://www.temis.nl/protocols/O3forecast.html)
• UV Radiation (http://www.temis.nl/uvradiation/UVindex.html)
• Medspiration (http://dup.esrin.esa.int/ionia/medspiration/year.asp)
• ATSR World Fire Atlas (http://dup.esrin.esa.int/ionia/wfa/index.asp)
• Swell tracking:
Pacific ocean (http://www.boost-technologies.com/esa/images/nrt_pac.gif)
• Swell tracking:
Atlantic ocean (http://www.boost-technologies.com/esa/images/nrt_atl.gif)
• Swell tracking:
Indian ocean (http://www.boost-technologies.com/esa/images/nrt_ind.gif)
• Earth Observation satellite orbits (http://orbits.eoportal.org/orbits.html)