Largest Lake in the World

Posted on May 6, 2008 by Rashid Faridi

There are a few different ways to define the world’s largest lake. Are we interested in the lake with the largest surface area? Or, the lake with the greatest water volume? And, should we consider the salt water seas in our comparison?

“Which lake is the World’s largest?” is not a simple question to answer. So, we will explore all of these questions and you will then have all of the many possible answers.


Map of the Caspian Sea – World’s Largest Land-Locked Water Body – by volume – Image by CIA

World’s Largest Lake (by volume):

The salty Caspian Sea is the world’s largest land-locked body of water. It contains approximately 18,900 cubic miles of water (78,700 cubic kilometers).

Lake Baikal is the world’s largest freshwater lake in terms of volume. It contains about 5521 cubic miles of water (23,000 cubic kilometers), or approximately 20% of Earth’s fresh surface water. This is a volume of water approximately equivalent to all five of the North American Great Lakes combined.


Map of Lake Baikal – World’s Largest Freshwater Lakeby volume- Image by CIA

World’s Largest Lake (by surface area):

The salty Caspian Sea has the greatest surface area of any lake at 143,200 square miles (370,886 square kilometers). Lake Superior, on the United States/Canada border is the freshwater lake with the greatest surface area at 31,700 square miles (82,103 square kilometers).


Map of Lake Superior l – World’s Largest Freshwater Lake – by surface area – Image by CIA

Largest Lake in the United States:

The largest lake in the United States is Lake Superior, one of the Great Lakes, located on the United States / Canada border. It is largest in both surface area 31,700 square miles (82,103 square kilometers) and in volume of water 2904 cubic miles (12,100 cubic kilometers).

source:http://geology.com

Posted in water | 5 Comments

Google Sets Sights On 3D Map of the Oceans

Posted on May 5, 2008 by Rashid Faridi

We’ve got Google Earth and Google Sky. Next up will be a map of the world below sea level–Google Ocean.

The company has assembled an advisory group of oceanography experts, and in December invited researchers from institutions around the world to the Mountain View, Calif., Googleplex. There, they discussed plans for creating a 3D oceanographic map, according to sources familiar with the matter.

The tool–for now called Google Ocean, the sources say, though that name could change–is expected to be similar to other 3D online mapping applications. People will be able to see the underwater topography, called bathymetry; search for particular spots or attractions; and navigate through the digital environment by zooming and panning. (The tool, however, is not to be confused with the “Google Ocean” project by France-based Magic Instinct Software that uses Google Earth as a visualization tool for marine data.)

Asked to comment on Google Ocean, a Google spokeswoman said the company had “nothing to announce right now.”

Oceanography researchers, however, say such a tool would be incredibly useful.

“There is no real terrain or depth model for the ocean in Google Earth,” said Tim Haverland, a geospatial application developer at the Fisheries Service of the National Oceanic and Atmospheric Administration (NOAA). “You can’t get in a submarine and in essence fly through the water and explore ocean canyons yet.”

Google Ocean will feature a basic layer that shows the depth of the sea floor and will serve as a spatial framework for additional data, sources said, adding that Google plans to try to fill in some areas of the map with high-resolution images for more detail.

Additional data will be displayed as overlying layers that depict phenomena like weather patterns, currents, temperatures, shipwrecks, coral reefs, and algae blooms, much like the National Park Service and NASA provide additional data for Google Earth and Google Sky.

“Google will basically just provide the field and then everyone will come flocking to it,” predicted Stephen P. Miller, head of the Geological Data Center at the Scripps Institution of Oceanography. “There will be peer pressure to encourage people to get their data out there.”

This is an image of a bathymetry map that shows the depth of the sea floor. It is based on sparse ship soundings and satellite altimeter measurements of subtle bumps and dips in the ocean surface which are produced by tiny variations in the pull of gravity.

(Credit: David Sandwell and Walter Smith/Scripps Institute of Oceanography)

While satellite imagery has the entire globe covered, as well as a good amount of known outer space, much less is known about the bodies of water that cover about 70 percent of the planet. Only a small percentage of the sea floor has been mapped in detail by sonar.

“It would take about 100 ship years to map the oceans at high resolution,” said Dave Sandwell, a professor of geophysics at the Scripps Institution of Oceanography.

Sandwell speculated that Google will get at least some of the basic sea floor data from Scripps’ Predicted Depth Map. Created from ship sonar soundings and satellites, it infers the depth of the sea floor based on the tiny bumps and dips in the ocean’s surface.
To bring more clarity to the sea floor, Sandwell and others said, Google will likely use high-resolution grids from oceanographic institutions showing the depths of select areas of the seas and paste them in. Data for those grids, which cover a very small portion of the sea floor, are created by ships using multibeam sonar.

One possible source for Google Ocean data are detailed “tiles” from multibeam and predicted topography compiled by the Lamont-Doherty Earth Observatory (LDEO) of Columbia University. Tiles are high-resolution sun-shaded images as well as digital elevation models covering the entire global ocean that allow for interactivity similar to Google Earth, where you can get different views by zooming in and out and by tilting the planet’s surface.

This screenshot shows an example of high-resolution imagery above and below sea level. The view is looking eastward at Monterey Bay on the California coast with the Sierra Nevada Mountains in the background. The continental slope is sculpted by submarine canyons with their numerous tributary gullies.

(Credit: GeoMapAppVG/Lamont-Doherty Earth Observatory of Columbia University)

“Our application gets data from databases over the Internet without the user having to know the name of the database or how to connect to it. Google could talk to our databases,” said William B. F. Ryan, an earth and environmental studies professor at Columbia’s LDEO.

Ryan cautioned that “Google would have to put the tiles on their servers because their public of millions would bring the servers at Columbia University to their knees.”

On top of the depth map, and in addition to the select high-resolution tiled areas, there will likely be various layers of specialized data from different sources. For example, NOAA already has made public visual information for Google Earth related to sea hotspots around coral reefs, Gulf of Mexico marine debris, surface temperatures and wave heights in the Great Lakes, and shipwrecks.

In addition to the “wow factor” Google Ocean will no doubt have for amateur oceanographers, marine enthusiasts, and anyone fascinated by the movie 20,000 Leagues Under the Sea, the project has the potential to promote more collaboration and advance research.

“We hope that one of the outcomes of Google Ocean will be an understanding of how much remains to be explored,” said Miller of Scripps. “We know far more about the surface of Mars from a few weeks of radar surveying in orbit than we know of the bottom of the ocean after two centuries.”

Source : http://www.news.com/

Posted in News, oceans | Leave a comment

Biofuels

Posted on May 5, 2008 by Rashid Faridi

A biofuel is difficult to define. Most of the fossil fuels we use are biological in nature. Perhaps we have to say that a biofuel is one that does not add to the stock of total carbon dioxide in the atmosphere. These are plant forms that, typically, remove carbon dioxide from the atmosphere, and give up the same amount when burnt. Naturally, all the other fossil fuels have done the same, but we are talking about a time scale of one or two years for the biofuels, whereas the fossil fuels can only be considered on a time scale measured in millions of years.

The biofuels are therefore considered to be “CO2 neutral”, not adding to the carbon dioxide level in the atmosphere. The type of biofuel used will depend on a number of factors, chief amongst them being the available feedstock and the energy that can be used locally.

Biodiesel

Biodiesel was probably the first of the alternative fuels to really become known to the public. The great advantage of biodiesel is that it can be used in existing vehicles with little or no adaptation necessary. Biodiesel is, naturally, a compromise for this reason, but still balances positively on the energy scales. There are energy plants available that will produce a higher yield in kWh per area, but the simplicity of having a fuel that is fully compatible with present fuel and engine technology makes it very attractive.

Cars running on BioEthanol, which is produced from agricultural crops, sugar cane or bio-mass, are governed by the same law of physics as those using gasoline. That means both emit CO2, as an inevitable consequence of the combustion process. But there is a crucial difference: burning ethanol, in effect, recycles the CO2 because it has already been removed from the atmosphere by photosynthesis during the natural growth process. In contrast, the use of gasoline or diesel injects into the atmosphere additional new quantities of CO2 which have lain fixed underground in oil deposits for millions of years.

Biogas

Biogas is becoming increasingly interesting as an alternative to natural gas. It is especially useful that the composition is practically identical, so the same burners can be used for both fuels. Biogas can be produced from plant or animal waste, or a combination of both. There are many different methods used dependent on the starting material and quantity involved. A mixtrue of both has proven to be the best method. The animal waste produces the nitrogen needed for growth of the bacteria and the vegetable waste supplies most ofthe carbon and hydrogen necessary.

Biomass

Biomass can be a practicable alternative for small district heating schemes in rural areas. Traditional biomass is wood residue and excess straw from agriculture being burned to provide heat or power. There are also gasification plants that produce a gas composed mainly of carbon monoxide and hydrogen from plant material. This has the advantage of being capable of transportation by pipeline or being filled into cylinders for distribution. Pyrolyis, as it is known, is being investigated in many countries presently.

Pyrolysis of Biomass

Pyrolysis of biomass is used to produce a mixture of three combustible products from biomass: tar, gas and coke are formed in varying proportions. After cleaning the gas can be used to drive turbines or gas motors. The tar is also suitable for the plastics industry and the coke can also be burned in the conventional way.

Landfill gas analyzer

The landfill gas analyzer is similar to a standard flue gas analyser, but capable of measuring methane and carbon dioxide directly. There are many landfill sites in use still, which all produce gas naturally. More advanced models of landfill gas analyzer will also be capable of measuring the products of combustion.

Landfill sites

Landfill sites are now being used for the commercial production of methane in many areas instead of simply flaring the gas for safety reasons. Methane is produced in commercially viable quantities for many years after a landfill site has been closed. Nevertheless, there are still many landfill sites where the gas is being wasted. This source will dry up in time to come, since many countires are now finally emphasising the separation of waste and recycling, but there is gas for the next twenty years in the landfill sites presently existing.

Measurements in biogas

Measurement of the concentrations of carbon dioxide and methane in biogas has produced interesting errors, probably due to the difference in size of the molecules. These factors require consideration when biogas is measured before combustion. Commercial use of biogas makes knowledge of the composition and heating value essential.

Methane digester

Although not a detailed description of how to build a methane digester, this is a good explanation of the working principle. The methane digester is a plant to produce methane in the form of biogas from plant and animal waste. Such systems are common in certain countries, such as India, but sorely neglected in others, although the raw material is available everywhere.

Biodigester construction in the Philippines

A specific section about a methane digester in use in the Philippines constructed with the very kind co-operation of the designer and builder, Gerry Baron. This section is updated when new information comes in about the biogas project. Biogas is one of those matters where results do not come immediately. It can take a few weeks for changes to take effect, so the changes will be sporadic, but they will come.

Posted in BIODIVERSITY, Environment, food security, Natural Resources | Leave a comment

Deepest Point in Ocean: Mariana Trench

Posted on May 5, 2008 by Rashid Faridi

Challenger Deep in the Mariana Trench is the deepest point in Earth’s oceans. The bottom there is 10,924 meters (35,840 feet) below sea level. If Mount Everest, the highest moutain on Earth, were placed at this location it would be covered by over one mile of water. The Challenger Deep is named after the British survey ship Challenger II, which discovered this deepest location in 1951.


Map of the Mariana Trench – Deepest Point in Earth’s Oceans – Image by CIA

Why is the ocean so deep here?

The Mariana Trench is located at a convergent plate boundary. Here two converging lithospheric plates collide with one another. At this collision point, one of the plates descends into the mantle. At the line of contact between the two plates the downward flexure forms a trough known as an ocean trench. An example of an ocean trench is shown in the diagram below.


USGS Image.

source:http://geology.com

Posted in Uncategorized | Leave a comment