Global Warming Out, Global Cooling In

Posted on July 13, 2008 by Rashid Faridi

“Watts Up With That?” published a very interesting post. Check it out. I am reproducing it.

Alan Lammey, Texas Energy Analyst, Houston

Four scientists, four scenarios, four more or less similar conclusions without actually saying it outright — the global warming trend is done, and a cooling trend is about to kick in. The implication: Future energy price response is likely to be significant.

Late last month, some leading climatologists and meteorologists met in New York at the Energy Business Watch Climate and Hurricane Forum. The theme of the forum strongly suggested that a period of global cooling is about emerge, though possible concerns for a political backlash kept it from being spelled out.

However, the message was loud and clear, a cyclical global warming trend may be coming to an end for a variety of reasons, and a new cooling cycle could impact the energy markets in a big way.

Words like “highly possible,” “likely” or “reasonably convincing” about what may soon occur were used frequently. Then there were other words like “mass pattern shift” and “wholesale change in anomalies” and “changes in global circulation.”

Noted presenters, such as William Gray, Harry van Loon, Rol Madden and Dave Melita, signaled in the strongest terms that huge climate changes are afoot. Each weather guru, from a different angle, suggested that global warming is part of a cycle that is nearing an end. All agreed the earth is in a warm cycle right now, and has been for a while, but that is about to change significantly.

However, amid all of the highly suggestive rhetoric, none of the weather and climate pundits said outright that a global cooling trend is about to replace the global warming trend in a shift that could begin as early as next year.

Van Loon spoke about his theories of solar storms and how, combined with, or because of these storms, the Earth has been on a relative roller coaster of climate cycles. For the past 250 years, he said, global climate highs and lows have followed the broad pattern of low and high solar activity. And shorter 11-year sunspot cycles are even more easily correlated to global temperatures.

It was cooler from 1883 to 1928 when there was low solar activity, he said, and it has been warmer since 1947 with increased solar activity.

“We are on our way out of the latest (warming) cycle, and are headed for a new cycle of low (solar) activity,” van Loon said. “There is a change coming. We may see 180-degree changes in anomalies during high and low sunspot periods. There were three global climate changes in the last century, there is a change coming now.”

Meanwhile, Madden noted that while temperature forecasts longer than one to two weeks out has improved, “what has really gotten much better is climate forecasting … predicting the change in the mean,” he said.

And the drivers impacting climate suggest a shift to cooler sea surface temperatures, he said.

Perhaps the best known speaker was Colorado State University’s Gray, founder of the school’s famed hurricane research team. Gray spoke about multi-decade periods of warming and cooling and how global climate flux has been the norm for as long as there have been records.

Gray has taken quite a bit of political heat for insistence that global warming is not a man-made condition. Man-made carbon dioxide (CO2) is negligible, he said, compared to the amount of CO2 Mother Nature makes and disposes of each day or century.

“We’ve reached the top of the heat cycle,” he said. “The next 10 years will be hardly any warmer than the last 10 years.”

Finally, climate scientist Melita spoke of a new phase in the Pacific Decadal Oscillation.

“I’m looking at a new, cold-negative phase, though it won’t effect this summer, fall or winter ‘08,” he said.

Conference host, analyst and forecaster Andy Weissman closed the conference by addressing how natural gas prices and policy debates would be impacted by a possible climate shift that could leave the market short gas.

This would be especially problematic if gas use for power generation were substantially increased at the expense of better alternatives.

“If we’re about to shift into another natural climate cycle, we can’t do it without coal-fired generation. So the policy debate has to change,” he said. “Coal has to be back on the table if we’re ever going to meet our energy needs.”

As for natural gas: “Next year, may see a bit of price softening,” Weissman said. “After that, fogetaboutit!”.
source:http://wattsupwiththat.wordpress.com/

Posted in Environment, Global Warming, News | 6 Comments

GPS Accuracy and WAAS

Posted on July 13, 2008 by Rashid Faridi

To determine an object’s location, the GPS system must receive a radio signal from at least three satellites. Since each satellite emits a unique signal, the receiver can then match the signal to the satellite and its orbital position. Distance from the receiver is then calculated (for each satellite), and from that data, the receiver accurately calculates its geographic position. But just how accurate is GPS?

GPS accuracy is affected by a number of factors, including satellite positions, noise in the radio signal, atmospheric conditions, and natural barriers to the signal. Noise can create an error between 1 to 10 meters and results from static or interference from something near the receiver or something on the same frequency. Clouds and other atmospheric phenomena, and objects such a mountains or buildings between the satellite and the receiver can also produce error, sometimes up to 30 meters. The most accurate determination of position occurs when the satellite and receiver have a clear view of each other and no other objects interfere.

Obviously, mountains and clouds can not be controlled or moved, nor can interference and blockage from buildings always be prevented. These factors then, will affect GPS accuracy. To overcome or get around these factors, other technology, AGPS, DGPS, and WAAS, has been developed to aid in determining an accurate location.

AGPS (Assisted Global Positioning System) is a system that assists conventional GPS when reception of the radio signal from the satellite is poor or non-existent (line of sight is blocked). To aid the GPS, the AGPS gains information via a wireless network, such as the GPS receivers on cell towers, to relay the satellite information to the receiver. With this assistance, the GPS doesn’t have to calculate the satellite’s orbit, which shortens initialization time, and increases battery life.

To further increase accuracy, DGPS (Differential Global Positioning System) technology was developed. Like the AGPS, the DGPS uses a fixed GPS location (such as a cell tower) to send information to the GPS receiver. DGPS, however, looks at both the satellite and the fixed location adjusts for any difference between the two, and then sends that information to the receiver. DGPS is particularly helpful when atmospheric conditions interfere with reception.

The most recent innovation in GPS technology is the WAAS (Wide Area Augmentation System) developed by the FAA and DOD to augment GPS for air navigation. Utilizing a network of ground-based stations (WRS or Wide-area Reference Stations) which are protected from the public, WAAS transmits corrections to geosynchronous communications satellites, which then transmit the corrections to the user. WAAS was designed to allow aircraft to rely on GPS for all phases of flights, including precision, or “instrument only” landings. Specifications for WAAS require accuracy of 7 meters or better both vertically and laterally, 95% of the time. In practice, WAAS achieved a lateral accuracy of 1 meter and of 1.5 meters vertically when over the contiguous United States.

Many GPS manufacturers market their products as the more accurate, or having greater sensitivity than their competitors, but the bottom line is that GPS accuracy depends on the GPS technology in use.

WAAS stands for Wide Area Augmentation System. Normally, unaided GPS is good for an accuracy of about 10 meters. WAAS provides an accuracy of 1.5 meters. WAAS was jointly developed by the Federal Aviation Administration (FAA) and the Department of Transportation (DOT) to provide precision approach capability for aircraft. The system was put into operation on July 10, 2003.

WAAS is similar to DGPS only it covers a much greater area – the entire continental U.S. and some of Alaska. While the system was developed for aviation, other areas benefit, too. It is used for mapping and surveying as well as providing greater accuracy for handheld and auto navigation receivers. For mapping and surveying purposes, accuracy is often less than one meter.

How it works
There are a few things that cause GPS not to be perfectly accurate. The charged particles of the ionosphere, and water vapor of the troposphere slow the signal slightly. Multipath, ephemeris errors, and the atomic clocks on the satellites themselves can also contribute to the inaccuracies.

Throughout the continental U.S. are 25 “reference stations.” These are GPS receivers that are placed at points that have been very accurately surveyed. These reference stations receive the same GPS signals as the moving receivers. The difference is instead of using the signal’s travel time to calculate position, the reference stations use their known position to calculate timing. Because the reference stations know exactly where they are, they can figure out what the travel time of the signals should be. They then compare the calculated times with the actual times. The difference is an “error correction” factor.

The error information is sent to two master stations (one on the U.S. east coast, one on the west coast) which calculate correction algorithms and assess the integrity of the system. A correction message is uplinked to the two WAAS satellites via a ground uplink system.

The two satellites are in geostationary orbits. These satellites then transmit the correction information back down to the GPS user on the GPS frequency. The GPS receiver then decodes this information and applies it to its calculated position to significantly improve the accuracy.

The benefits of WAAS to civil aviation will be considerable. WAAS improves the efficiency of aviation operations due to:
Greater runway capacity
Reduced aircraft separation which allows increased capacity in a given airspace
More direct enroute flight paths
New precision approach services
Reduced and simplified equipment on board aircraft
Substantial cost savings due to the elimination of maintaining older navigation aids
Europe has an equivalent of WAAS called EGNOS (European Geostationary Navigation Overlay Service). . Japan is also developing a similar system called MSAS (Multi Functional Transport Satellites MTSAT] Satellite – Based Augmentation System).

Links:http://www.maps-gps-info.com/gps-accuracy.html

http://www.maps-gps-info.com/waasexp.html

http://www.maps-gps-info.com/waasexp.html

Posted in GIS, GPS, Remote Sensing 101 | Tagged | 3 Comments

What’s Wrong with the Sun? (Nothing)

Posted on July 12, 2008 by Rashid Faridi

So says NASA solar physicist David Hathaway. “There have been some reports lately that Solar Minimum is lasting longer than it should. That’s not true. The ongoing lull in sunspot number is well within historic norms for the solar cycle.”

This report, that there’s nothing to report, is newsworthy because of a growing buzz in lay and academic circles that something is wrong with the sun. Sun Goes Longer Than Normal Without Producing Sunspots declared one recent press release. A careful look at the data, however, suggests otherwise.

But first, a status report: “The sun is now near the low point of its 11-year activity cycle,” says Hathaway. “We call this ‘Solar Minimum.’ It is the period of quiet that separates one Solar Max from another.”

The solar cycle, 1995-2015. The “noisy” curve traces measured sunspot numbers; the smoothed curves are predictions. Credit: D. Hathaway/NASA/MSFC.

During Solar Max, huge sunspots and intense solar flares are a daily occurance. Auroras appear in Florida. Radiation storms knock out satellites. Radio blackouts frustrate hams. The last such episode took place in the years around 2000-2001.

During Solar Minimum, the opposite occurs. Solar flares are almost non-existant while whole weeks go by without a single, tiny sunspot to break the monotony of the blank sun. This is what we are experiencing now.

Although minima are a normal aspect of the solar cycle, some observers are questioning the length of the ongoing minimum, now slogging through its 3rd year.

“It does seem like it’s taking a long time,” allows Hathaway, “but I think we’re just forgetting how long a solar minimum can last.” In the early 20th century there were periods of quiet lasting almost twice as long as the current spell. (See the end notes for an example.) Most researchers weren’t even born then.

Hathaway has studied international sunspot counts stretching all the way back to 1749 and he offers these statistics: “The average period of a solar cycle is 131 months with a standard deviation of 14 months. Decaying solar cycle 23 (the one we are experiencing now) has so far lasted 142 months–well within the first standard deviation and thus not at all abnormal. The last available 13-month smoothed sunspot number was 5.70. This is bigger than 12 of the last 23 solar minimum values.”

In summary, “the current minimum is not abnormally low or long.”

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The longest minimum on record, the Maunder Minimum of 1645-1715, lasted an incredible 70 years. Sunspots were rarely observed and the solar cycle seemed to have broken down completely. The period of quiet coincided with the Little Ice Age, a series of extraordinarily bitter winters in Earth’s northern hemisphere. Many researchers are convinced that low solar activity, acting in concert with increased volcanism and possible changes in ocean current patterns, played a role in that 17th century cooling.

For reasons no one understands, the sunspot cycle revived itself in the early 18th century and has carried on since with the familiar 11-year period. Because solar physicists do not understand what triggered the Maunder Minimum or exactly how it influenced Earth’s climate, they are always on the look-out for signs that it might be happening again.

The quiet of 2008 is not the second coming of the Maunder Minimum, believes Hathaway. “We have already observed a few sunspots from the next solar cycle,” he says. (See Solar Cycle 24 Begins.) “This suggests the solar cycle is progressing normally.”

What’s next? Hathaway anticipates more spotless days, maybe even hundreds, followed by a return to Solar Max conditions in the years around 2012.

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Posted in News, Solar System | 2 Comments

The Edge of Sunshine

Posted on July 12, 2008 by Rashid Faridi

While searching about solar power I came across an interesting piece on NASA website.Though a bit old it is still relevent.

Try this: Close your eyes for a moment and imagine the International Space Station (ISS), sunlit and gleaming as it circles our planet.What did it look like? The lingering image in your mind is probably dominated by broad, beautiful wings — the station’s awesome solar arrays.

It’s no accident that solar panels dominate the station’s profile. On the ISS (as on the earth below) solar energy ultimately powers everything that happens. Our Sun, a star named Sol, radiates enormous power: a constant output of 4 x 1023 kilowatts (kW), which is a 4 followed by 23 zeros! Photovoltaic cells, which convert sunlight to electricity, need only intercept a tiny fraction of that total to energize the station.

But not all spacecraft linger near Earth where sunlight is plentiful. Many NASA probes travel far beyond our planet’s orbit. And as they do, the Sun grows more distant and dim. Somewhere out there, solar power ceases to be a useful source of energy for spacecraft. But where?

That’s what NASA spacecraft builders want to know: Where is the edge of sunshine?

The Space Station’s solar cells, developed decades ago, convert 14% of the Sun’s energy that hits them into electricity, and modern multibandgap cells, which convert light in multiple parts of the spectrum into electric power, reach efficiencies of 30% or so. Such devices work well enough in the brightly-lit inner solar system, but more efficient cells and larger arrays will be needed as spacecraft travel to places where solar photons are scarce. In the outer reaches of the solar system, for instance, the ability to convert even single photons into electricity would be important.

“Sunlight decreases in intensity over distance by a factor of 1/r2, where r is the distance from the Sun,” explains Geoff Landis, a scientist at NASA’s Glenn Research Center. “This means a 1-meter-square solar array producing 400 watts at a distance of 1 AU would have to be 25 square meters in size out at Jupiter — and almost 2,000 square meters at Pluto to yield the same power.” (Note: An astronomical unit or “AU” is the mean distance between Earth and the Sun. 1 AU equals 150 million kilometers.)


Left: The Sun as viewed from distant Pluto is just another star in the night sky, albeit the brightest one. Space artist (and space physicist) Dan Durda painted this view from the 9th planet.

Landis and his colleagues at Glenn’s Photovoltaics and Space Environment Branch are exploring new ways to harness the Sun’s power — including more efficient solar cells, laser-beaming energy to distant spacecraft, and solar power systems for the Moon and Mars. “The use of solar power is a complex field of study,” says Landis. “Finding solutions requires that we balance such factors as distance, weight, the energy of different light bands, and the actual materials available to us.”

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