Taking our planet's pulse

Photo: Clive Simpson

High resolution radar data maps of Europe, North America and other key parts of the world captured on a space shuttle mission 14 years ago have been made public for the first time this month.

Former Nasa astronaut Kathy Sullivan, now head of the US National Oceanic and Atmospheric Administration (NOAA), welcomed the release of previously secret data. "The declassification of 30 metre elevation data represents a vast improvement over the previous freely available data set which resolved to just 90 m," she says.

This second tranche of high resolution data to be released under the direction of  President Obama follows on from highly accurate terrain maps of Africa which became available in October.   

Nasa's ground-breaking Shuttle Radar Topographic Mission (SRTM) recorded digital elevation data (DEMs) in February 2000 for over 80 per cent of the globe - but until now only a 90 m resolution version was released.

The 30 m resolution data was kept secret for use by the US military and intelligence agencies - but even the 90 m resolution data revealed for the first time detailed swaths of the planet's topography previously obscured by persistent cloudiness.

"SRTM was among the most significant science missions the shuttle ever performed," says Michael Kobrick, SRTM mission project scientist at the Jet Propulsion Laboratory (JPL). "It's probably the most significant mapping mission of any single type ever."

SRTM consisted of a specially modified radar system comprising two radar antennas - one located in the shuttle's payload bay, the other on the end of a 60 m mast extending into space.

The surface of Earth was mapped numerous times from different perspectives and the combined radar data processed at JPL in California to produce a series of global topographic maps.

Topography influences many natural processes, such as the distribution of plant communities and the associated animals that depend upon them, weather and rainfall patterns, and the flow and storage of surface water.

The digital elevation maps benefit many activities, from aviation safety to civil engineering projects, and the data is helpful in predicting and responding to flooding from severe storms and the threats of coastal inundation associated with storm surges, tsunamis and rising sea-levels.

Dr Sullivan says aid organisations, development banks and decision-makers in developing countries will be able to better map and plan for climate-driven challenges.

“Space-based observations are the foundation for applications so environmental intelligence services are increasingly vital to decision makers in all sectors of society as they confront a rapidly changing world and uncertain future.”

She called upon the world space community to develop new and more resilient Earth observation systems that are now increasingly relied upon “take the pulse” of our planet .

"Measured data of our planet tells us we are living in a worrying world," she said. "We are seeing longer, more frequent and hotter heatwaves over most land masses and we expect to see that trend continue in the future."

Andes mountains in Ecuador, home to the highest active volcano in the world

Data is also revealing the remarkable pace at which Arctic sea ice is continuing to shrink and thin, and the Northern Hemisphere's snow cover is decreasing as global mean surface temperature rises. 

“Sea level has risen an average of 3 mm a year in the last several decades and will continue to rise in the decades ahead which will exacerbate the hazards that coastal communities face from coastal storms,” said Dr Sullivan. “This is a problem because humankind is concentrating increasingly in the coastal settlements.

"Many aspects of climate change will persist for centuries, even if right now we cease all CO2 emissions forever. Carbon that has been emitted in the past decades is locked in and the process that it has unleashed will take centuries more to play out.

"All of this leads to heightened social vulnerability, in a world where the population will increase from the current seven billion to nine billion by 2040 - and that implies that we will have to double the current food supply globally if we are to feed that larger population," she added.

"We are moving into a very different world. Environmental intelligence is a really critical asset and product that the world needs from space. It provides us with foresight about conditions that have not yet come to exist and about the solutions we need to plan ahead for."