"Our loyalties are to the species and the planet. We speak for Earth. Our obligation to survive and flourish is owed not just to ourselves, but also to that Cosmos, ancient and vast, from which we spring." - Carl Sagan
The theme for Earth Day 2014 is ‘green cities’. As more and more people move to cities in search of jobs – and the reality of climate change becomes increasingly clear – the need to create sustainable communities is more important than ever. Recognised this year as the European Green Capital, Copenhagen has set a prime example with investments in sustainable technology, forward-thinking public policy and an educated and active public. The Danish city is a good model in terms of urban planning and design, and is working towards becoming carbon-neutral by the year 2025.
Image credit & copyright: Airbus Defence and Space
Brussels from Sentinel-1A
Acquired on 12 April 2014 at 17:18 GMT (19:18 CEST), just nine days after launch, this first image from Sentinel-1A captures Brussels and surrounds in Belgium. It was acquired in the satellite’s ‘strip map’ mode, which has a swath width of 80 km, and in dual polarisation. The image also shows a more detailed view of the city in the ‘zoom in’. Antwerp harbour is also visible in the top left. The green colours correspond to vegetation, red–blue to urban areas, white to high-density urban areas and black to waterways and low-reflective areas such as airport runways.
Image credit: ESA
Salt marsh, Kazakhstan
This satellite image was acquired over the edge of a salt marsh near the northeast Caspian Sea in southwestern Kazakhstan.
The Caspian Sea (not pictured) is the largest inland body of water by surface area. With an average depth of about 5 m, the northern part of the Caspian is very shallow, while the central and southern parts of the sea are much deeper. The salinity of the waters also change from north to south, being more saline in the northern, shallow waters and less in the south.
The salt marsh in the upper section of this image was once a gulf of the Caspian Sea, but fluctuating sea levels over the last decades cause it to be cut off occasionally from the main body of water and even dry up. In this image, it appears that the water has evaporated, leaving behind a white salt crust.
Rock formations dominate the central part of the image, while a plateau stretches south and east (not pictured). The visible shapes in combination with the dark colour of the rocks may indicate that they are volcanic, with water erosion evident in the finger-like runoff patterns.
The grey rim between the land and salt pan comes from the sedimentary runoff from the land mixing with the saltwater. When the marsh is dry, a greyish colour is left behind.The arid climate in this region makes it easy to acquire optical imagery from satellites, without the obstruction of visibility by clouds.
Image credit & copyright: KARI/ESA
Hundreds of fields speckle the northern Italian landscape south of the Po River in this satellite image.
Agriculture is one of the main economic uses of the Po Basin because of the fertile soils, and this image clearly shows a landscape dominated by fields.
Throughout Italy’s history, agricultural landowners would often divide their properties among their male heirs. Generation after generation, land would be further fragmented, resulting in the millions of small plots found across the country today.
Optical satellite imagery like this can be used to monitor agriculture and changing landscapes. Satellites can provide the information necessary to make informed decisions on agricultural management, including yield prediction, irrigation, planting, pricing and regional need for food assistance if a harvest is likely to fail.
At the very bottom of the image, foothills of the Apennine mountains appear dark green.
The city of Bologna is visible in the lower-right corner, and Modena can be seen on the left. Two roads cutting across the flat Po Valley provide a nearly straight route between the cities.
The city of Cento – which means ‘hundred’ in Italian – is located in the upper-right section of the image on the Reno river.
Image credit: JAXA/ESA
Hekla may be stirring
Recent GPS measurements of ground deformation (in the form of a swelling bulge on the north face) and a swarm of small seismic events last week suggest that Iceland’s most active smoker has a full lava chamber 8 km down, and may be preparing to erupt. Three further quakes have taken place over the last 24 hours. It is known to do so at very short notice (79 minutes from first quake to eruption in the last one in 2000), so climbing has been banned and multilingual hazard signs put out on the approaches to the 1,491 metre stratovolcano, whose last large eruption was in 1947.
Both these symptoms suggest that magma is shifting deep within the edifice, though not necessarily that it is about to blow. Similar movements happened without eruption last year and in 2011 without such an occurrence. Many of its eruptions are small, but some have lasted months and affected global climate through the emission of ash and sulphurous gases. Over 10% of the tephra (ash and rock fall) on the island, an outcrop of the mid Atlantic ridge/spreading centre, are thought to have spouted from this peak.
Hekla consists of a 5.5 km long volcanic ridge with several vents, including the stratovolcano, located where the rift encounters a transform strike slip fault. Minor extensional forces on this junction would open up the passage for the magma to rise up and fill the chamber. Its products are fluorine rich basaltic andesites , which can poison animals eating the ash covered grass, a process that has led to several historical famines.
Image credit: Matthias Burch
Data from satellite sensors show that during the Northern Hemisphere’s growing season, the Midwest region of the United States boasts more photosynthetic activity than any other spot on Earth, according to NASA and university scientists.
Healthy plants convert light to energy via photosynthesis, but chlorophyll also emits a fraction of absorbed light as fluorescent glow that is invisible to the naked eye. The magnitude of the glow is an excellent indicator of the amount of photosynthesis, or gross productivity, of plants in a given region.Research in 2013 led by Joanna Joiner, of NASA’s Goddard Space Flight Center in Greenbelt, Md., demonstrated that fluorescence from plants could be teased out of data from existing satellites, which were designed and built for other purposes. The new research led by Luis Guanter of the Freie Universität Berlin, used the data for the first time to estimate photosynthesis from agriculture. Results were published March 25 in Proceedings of the National Academy of Sciences.According to co-author Christian Frankenberg of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., “The paper shows that fluorescence is a much better proxy for agricultural productivity than anything we’ve had before. This can go a long way regarding monitoring – and maybe even predicting – regional crop yields.”