Fire Earth

Earth is fighting to stay alive. Mass dieoffs, triggered by anthropogenic assault and fallout of planetary defense systems offsetting the impact, could begin anytime!

Archive for the ‘water cycle’ Category

Earth’s water cycle has accelerated: Researcher

Posted by feww on April 17, 2010

Ocean salinities show an intensified water cycle

Public Release: CSIRO Australia

Evidence that the world’s water cycle has already intensified is contained in new research to be published in the American Journal of Climate.

The stronger water cycle means arid regions have become drier and high rainfall regions wetter as atmospheric temperature increases.

The study, co-authored by CSIRO scientists Paul Durack and Dr Susan Wijffels, shows the surface ocean beneath rainfall-dominated regions has freshened, whereas ocean regions dominated by evaporation are saltier. The paper also confirms that surface warming of the world’s oceans over the past 50 years has penetrated into the oceans’ interior changing deep-ocean salinity patterns.

“This is further confirmation from the global ocean that the Earth’s water cycle has accelerated,” says Mr Durack – a PhD student at the joint CSIRO/University of Tasmania, Quantitative Marine Science program.

“These broad-scale patterns of change are qualitatively consistent with simulations reported by the Intergovernmental Panel on Climate Change (IPCC).

“While such changes in salinity would be expected at the ocean surface (where about 80 per cent of surface water exchange occurs), sub-surface measurements indicate much broader, warming-driven changes are extending into the deep ocean,” Mr Durack said.

The study finds a clear link between salinity changes at the surface driven by ocean warming and changes in the ocean subsurface which follow the trajectories along which surface water travels into the ocean interior.

The ocean’s average surface temperature has risen around 0.4ºC since 1950. As the near surface atmosphere warms it can evaporate more water from the surface ocean and move it to new regions to release it as rain and snow. Salinity patterns reflect the contrasts between ocean regions where the oceans lose water to the atmosphere and the others where it is re-deposited on the surface as salt-free rainwater.

“Observations of rainfall and evaporation over the oceans in the 20th century are very scarce. These new estimates of ocean salinity changes provide a rigorous benchmark to better validate global climate models and start to narrow the wide uncertainties associated with water cycle changes and oceanic processes both in the past and the future – we can use ocean salinity changes as a rain-gauge,” Mr Durack said.

Based on historical records and data provided by the Argo Program’s world-wide network of ocean profilers – robotic submersible buoys which record and report ocean salinity levels and temperatures to depths of two kilometres – the research was conducted by CSIRO’s Wealth from Oceans Flagship and partially funded by the Australian Climate Change Science Program. Australia’s Integrated Marine Observing System is a significant contributor to the global Argo Program.

Contact: Craig Macaulay
Craig.Macaulay@csiro.au
CSIRO Australia

Related Links:

.

Serial No 1,583. Starting April 2010, each entry on this blog has a unique serial number. If any of the numbers are missing, it may mean that the corresponding entry has been blocked by Google/the authorities in your country. Please drop us a line if you detect any anomaly/missing number(s).

Posted in Climate Change, ocean surface, Ocean Warming, water cycle | Tagged: , , , , | Leave a Comment »

ESA Says Australia Dry!

Posted by feww on February 24, 2010

Finally, the first calibrated images are being delivered by ESA’s SMOS mission. Most what they tell us we already know. AND, NO, they couldn’t program ESA SMOS to do a rain dance. But let’s at least hope that the images would help convince the world government to keep the hydrocarbons buried inside the earth, where they belong. Fire-Earth

Public Release: European Space Agency

First images from ESA’s water mission

In less than four months since launch, the first calibrated images are being delivered by ESA’s SMOS mission. These images of ‘brightness temperature’ translate into clear information on global variations of soil moisture and ocean salinity to advance our understanding of the water cycle.

Launched on 2 November, the Soil Moisture and Ocean Salinity (SMOS) mission is improving our understanding of Earth’s water cycle by making global observations of soil moisture over land and salinity over oceans. By consistently mapping these two variables, SMOS will not only advance our understanding of the exchange processes between Earth’s surface and atmosphere, but will also help to improve weather and climate models.

In addition, the data from SMOS will have several other applications in areas such as agriculture and water resource management.

SMOS captures images of ‘brightness temperature’, which then require substantial processing to realise information on soil moisture and ocean salinity. Brightness temperature is a measure of the radiation emitted from Earth’s surface. During the commissioning phase, considerable effort is put into improving the quality of these images of brightness temperature before using them as input for the soil moisture and ocean salinity data products. ESA is now in a position to show the first results, which are very encouraging.


This is a calibrated image of brightness temperature over Australia. Compared to the uncalibrated image, the “noise” in the product has been reduced so that the coast lines and physical features of the landscape are much sharper. Credit: ESA

Since it was launched, engineers and scientists from various institutes in Europe have been busy commissioning the SMOS satellite and instrument. This commissioning phase, which will continue until the end of April, initially involved testing the Proteus platform – a generic ‘satellite bus’ developed by the French space agency CNES and Thales Alenia Space – and the all-important MIRAS instrument developed by EADS-CASA in Spain under contract to ESA. Both platform and instrument have shown excellent performance during their first four months in orbit.

Achim Hahne, ESA’s SMOS Project Manager, said, “Our development team is extremely happy and proud to see the real performance of the SMOS system in orbit. We are only half-way through the in-orbit commissioning phase and it is rewarding to see these first very promising calibrated products delivered by SMOS.”

Among other tasks, commissioning also includes testing the system that sends the data to the ground and the process through which the data is distributed, as well as calibrating the data products delivered by MIRAS – the Microwave Imaging Radiometer with Aperture Synthesis instrument.

MIRAS produces a snapshot of brightness temperature every 1.2 seconds. The image of Scandinavia shows one snapshot acquired by SMOS. From these images of brightness temperature, it is possible to derive how much moisture there is in the surface layers of soil and how much salt there is in the surface waters of the oceans. High brightness temperatures translate into dry soils and low brightness temperatures into wet areas. This is why bodies of water show up as cold spots.

Calibration and validation are a major undertaking in any Earth observation mission. Once the data get to the ground, they need to be checked that they make sense and can be used for scientific research. The last three months have been dedicated to performing these calibration activities in order to assess the performance of the mission.

This first calibration step is important to ensure the instrument meets the required performance. The process also includes making corrections for errors caused by, for example, temperature variations in the instrument’s antenna receivers or light reflected from the Sun and Moon. The effect is instantly visible in the calibrated image of Australia, where geophysical features, such as lakes, are clearly visible, compared to the uncalibrated image.

The image showing Brazil highlights the rainforest, which is relatively stable and bright, and the Amazon River is seen in lower brightness temperatures.

Susanne Mecklenburg, who, as ESA’s SMOS Mission Manager, will formally take over the reins of the mission at the end of commissioning said, “It is exciting to see these first data products, which are already of excellent quality, even though we haven’t completed all the calibration activities yet. We also had very positive feedback from the scientists who have already started using the data.”

Yann Kerr, who first proposed the mission to ESA, added, “SMOS has delivered its first products earlier than expected and of a quality better than the specifications.”

The acquisition of these calibrated images marks a very important step in the progress of the SMOS mission and also demonstrates the excellent quality and availability of the data, which will soon be available to the science community.

Jordi Font, the mission’s Lead Investigator for ocean salinity, said, “For the ocean products, a lot of work still has to be done before the release of operational data. The low sensitivity to variations in salinity requires very accurate instrument calibration and data processing to achieve the mission’s measurement goals for ocean salinity. However, the excellent performance of MIRAS, and the work being done in commissioning means we are very close to obtaining good results for measuring salinity.”

The commissioning phase will continue to the end of April, after which the mission will be operational. However, the science team will continue to asses the quality of the data products throughout the lifetime of the mission. An airborne validation campaign is under way in Australia, comparing in situ measurements with those taken by the satellite. In addition, extensive airborne campaigns will be carried out in Germany, Spain and France in the spring.

Contact: Robert Meisner
robert.meisner@esa.int
European Space Agency

Related Links:

Posted in ESA, ESA SMOS, Ocean Salinity, Soil Moisture, water cycle | Tagged: , , , , | Leave a Comment »