Archive for the ‘Blog Article’ Category

UAH Global Temperature Update for May, 2014: +0.33 deg. C

Tuesday, June 10th, 2014

The Version 5.6 global average lower tropospheric temperature (LT) anomaly for May, 2014 is +0.33 deg. C, up from April (click for full size version):
UAH_LT_1979_thru_May_2014_v5

The global, hemispheric, and tropical LT anomalies from the 30-year (1981-2010) average for the last 17 months are:

YR MON GLOBAL NH SH TROPICS
2013 1 +0.497 +0.517 +0.478 +0.386
2013 2 +0.203 +0.372 +0.033 +0.195
2013 3 +0.200 +0.333 +0.067 +0.243
2013 4 +0.114 +0.128 +0.101 +0.165
2013 5 +0.082 +0.180 -0.015 +0.112
2013 6 +0.295 +0.335 +0.255 +0.220
2013 7 +0.173 +0.134 +0.211 +0.074
2013 8 +0.158 +0.111 +0.206 +0.009
2013 9 +0.365 +0.339 +0.390 +0.190
2013 10 +0.290 +0.331 +0.249 +0.031
2013 11 +0.193 +0.160 +0.226 +0.020
2013 12 +0.266 +0.272 +0.260 +0.057
2014 1 +0.291 +0.387 +0.194 -0.029
2014 2 +0.170 +0.320 +0.020 -0.103
2014 3 +0.170 +0.338 +0.002 -0.001
2014 4 +0.190 +0.358 +0.022 +0.093
2014 5 +0.329 +0.326 +0.333 +0.173

This is the 3rd warmest May in the satellite record:
1998 +0.56 (warm ENSO)
2010 +0.45 (warm ENSO)
2014 +0.33 (neutral)

John Christy thinks the coming El Nino will give us a new temperature record, since it is superimposed on a warmer baseline than the super El Nino of 1997-98. I’m not convinced, since we are in the cool phase of the PDO, which favors weak El Ninos (like 2009-10).

As we finish up our new Version 6 of the UAH dataset, it looks like our anomalies in the 2nd half of the satellite record will be slightly cooler, somewhat more like the RSS dataset….but we are talking small adjustments here…hundredths of a deg. C.

The global image for May should be available in the next day or so here.

Popular monthly data files (these might take a few days to update):

uahncdc_lt_5.6.txt (Lower Troposphere)
uahncdc_mt_5.6.txt (Mid-Troposphere)
uahncdc_ls_5.6.txt (Lower Stratosphere)

Boatside Report on Lake Superior Ice

Friday, June 6th, 2014

As of June 5, 2014, the only ice on Lake Superior that remains clearly visible in the 250 meter resolution MODIS satellite data are several bergs northeast of Ashland, Wisconsin:

ice-rafts near-Ashland-June-5-2014

I contacted Mark Vinson at the USGS Great Lakes Biological Station, in Ashland, Wisconsin, to see if anyone has gone out to take photos of the remaining ice rafts on “the big lake they call Gitche Gumee“.

It turns out Mark is out on the lake for their month-long nearshore fish community survey, done every year on R/V Kiyi, now heading east towards Marquette. They are also taking some photos of the remaining ice, much of which is hugging the shore and apparently is not visible in the MODIS satellite imagery.

For example, here’s a photo of icebergs in Sand Bay, in the Michigan’s Keweenaw Peninsula, taken from the Kiyi yesterday:
Lake-Superior-ice-Sand-Bay-MI-June-5-2014

You can monitor the location of R/V Kiyi in real time with this great Google Maps tool Great Lakes & Seaway Shipping Online Vessel Passage Maps. Here’s its current location:
RV-Kiyi-location-June-6-2014

Forget Solar Roadways. Here’s How to Get Limitless, Clean Energy

Thursday, June 5th, 2014

I’m still marveling at the number of people who think moving solar collectors from where they stay clean, generate more energy, and are protected, to locations where they are made dirty, generate less energy, and are destroyed, is a good idea. (See my post about Solar Roadways).

So I started looking at other alternative energy technologies. Such as putting wind turbines on your car to generate energy, like the one produced by this Chinese inventor:
wind-power-car

But I wanted more. “Perpetual motion” has gotten such a bad rap, and I wanted to see if any progress has been made on this subject…

Well, I think I found the modern-day expert. I think this guy really understands how scientists and engineers have been fooling us for so many years with their negative thinking.

Such as with their supposed “laws” of thermodynamics which always seem to state what we can’t do…rather than what we can do!

Check out some of these insights, taken from Ken Amis’s treatise, Energy Independence: Perpetual Motion is the Way to Go:

“Establishment scientists have, throughout history, ridiculed and dismissed such independent thinkers without seriously considering the details of their ideas. We should not dismiss all of this effort as futile or misguided. It may be that these inventors were the true visionaries, following the correct path, undaunted by failures, not allowing themselves to be discouraged by naysayers, and not swallowing the big lies perpetrated by mainstream scientists.

And what has mainstream science and engineering given us? It has given us energy-guzzling machines that must be fed with fossil fuels ripped at great cost from the earth, stoking the fires of industry while spewing out unhealthy waste products that foul our air, water and earth. By contrast, all perpetual machine designs ever conceived have these virtues: (1) No fossil fuels are required, indeed no fuel at all is needed. (2) They do not produce noxious and toxic exhaust gasses or solid pollution, for they produce no exhaust.”

Clearly, this guy can see through the veil of deceit and trickery the “experts” have used to stifle progress toward clean, inexhaustible sources of energy. Amis continues:

“Perpetual motion machine inventors shouldn’t be intimidated by the laws of thermodynamics. The thermodynamic laws were invented by engineers and physicists during the industrial revolution to discourage those restless minds seeking alternatives to those incredibly inefficient coal-burning engines. Then physicists tried to add clout to the laws by cloaking them in an incomprehensible mathematical theory called statistical mechanics. Not one in a hundred degree-holding physicists or engineers really understands where these laws come from. Even the great physicist Maxwell had to enlist the aid of a demon to make sense of it all.

Instead of making laws about what can’t be done, scientists should instead invent laws that show us the ways things can be done. The negative character of thermodynamics laws does nothing but stifle and discourage creative and inventive minds from the quest for perpetual motion machines. Scientists nurtured in this climate of negativity have not, and never will, discover the secret of perpetual motion. They haven’t a clue how it might be accomplished.

By going down the wrong path, science has become more and more complicated, so it’s now too difficult for any but a few in the elite scientific priesthood to understand. It’s time to say “enough!” and return to the basics of simple things that any basement or backyard inventor can grasp. We can no longer expect narrow-minded and closed-minded scientists, who waste their time mucking around with higher mathematics, to be able to understand simple things. Having lost any firm connection with reality, they have sold their souls to mathematics.”

Ken Amis is CEO of Entropy Innovations. I hope that he considers crowdfunding of some of his thinking-outside-the-box ideas. There is no reason why we can’t, at a minimum, be producing 1,000 miles/gal carburetors while we are actively working on some of these other areas:

  • Liberating scientific thought from the limitations of the laws of thermodynamics.
  • Production of unlimited non-polluting energy.
  • Practical entropy reversal.
  • Fabrication of materials with negative friction coefficients.
  • Energy extraction from magnetic or gravitational fields.
  • Exploiting loopholes in the uncertainty principle.
  • Conversion of virtual work to real work.

Last Ice on Lake Superior Revealed by NASA Satellites

Wednesday, June 4th, 2014

An amazingly clear day today over Lake Superior allowed the MODIS instruments on the NASA Aqua and Terra satellites to capture images of the last remaining major ice rafts on the lake. Both are near the south shore of Superior. It would be interesting to get some boat-side pics of these if anyone up there is willing to take on the challenge (but don’t fall in!).

The largest ice raft, as much as 1 mile in diameter, is northeast of Ashland, Wisconsin. It is accompanied by smaller ice areas generally to the south of it (click for large version):
Lake-Superior-last-ice-Ashland

A smaller raft of ice remains northwest of Munising and Grand Island, Michigan:
Lake-Superior-last-ice-Marquette

Still smaller, but next to shore (and a little questionable) are two ice areas near L’Anse. I suspect these will be gone tomorrow or the next day:
Lake-Superior-last-ice-LAnse

I doubt that these will last too many more days. Since the water in the vicinity of these ice rafts will be close to freezing, I would caution people to not walk on them. A person will not last long in water that cold. If you walk out on one, and you fall in, your friends in the boat won’t be able to reach you without risking their lives, too.

My List of Hurricane Names to Strike Fear in our Hearts

Tuesday, June 3rd, 2014

hurricane-face
The title of a new PNAS study is, believe it or not, Female Hurricanes are Deadlier than Male Hurricanes.

Researchers found that hurricanes striking the U.S. killed on average twice as many people if they had a female name rather than a male name. Outlier storms such as Katrina (2005) were excluded from the analysis.

The researchers are convinced that the reason is because we don’t take female hurricanes seriously. Seriously.

To support their conclusion, in surveys of college students they also found that students were more likely to say they would evacuate when asked about the approach of a hypothetical storm that had a male, rather than a female name. When explicitly asked if their decision would be affected by the storm’s gender, they said no…but their response to specific storm names was biased anyway.

As you might recall (if you are old enough), the switch from all-female names occurred in 1979 for the Atlantic basin, to counter claims that the long-standing practice of using only female names was sexist. I remember well the mood in the country back then. The last thing you wanted to be called was “sexist”.

Clearly, we need a set of names that is menacing. No Hurricane Heathers or Missys.

So, in the interests of moving the ball forward and saving some lives, here’s my proposed list. They are mostly all male names, because we can’t have people dying just because they won’t get out of the way of Hurricane Angelica.

SUGGESTED OFFICIAL HURRICANE NAMES

Adolf (all WWII veterans & German tourists would evacuate)
Butch (THE most masculine name of the 1950s)
Chase (hurry! it’s gaining on us!!)
Dallas (dripping with testosterone)
Ezekiel (“may God strengthen him”)
Fidel (99% of all Cuban-Americans would evacuate)
Gusto (wind gust, oh, about 150 mph)
Hillary (would you believe…Sir Edmund?)
Ivan (has that manly, Russian, crazy-Ivan feel)
Jezebel (don’t trust any forecasts of this one)
Katrina (that bitch is back again?)
Luthor (as in Lex —)
Manley (well, DUH)
Noah (flooding could be widespread)
Ozzy (that storm will hit like a crazy train on a dark Sunday)
Pandora (you don’t fly into this one)
Quentin (you might not escape from this one)
Rocky (’nuff said)
Stormy (yup)
Tyrone (seems very masculine to me)
Ulysses (destined to be the strongest storm on record)
Victor (evacuate or you lose)
Waylon (this outlaw storm gonna wail on you)
Xena (better get out of her way)
Yuk (a very messy storm)
Ziba (biblical, “strength” or “fight”)

We would also stop retiring storm names that were especially severe. Hopefully, people would get out of the way if Hurricane Katrina came to visit again. Eventually, just about every name would strike fear in our hearts because we would be reminded of just how bad Hurricane Adolf was way back in 2015.

Obamas New Powerplant CO2 Rules: Guaranteed to Succeed (Retroactively)

Monday, June 2nd, 2014

coal-fired-power-plants-in-the-US
Its hard to find anything new to say about the new EPA rules being announced by the Administration today that seek to lower CO2 emissions from coal-fired power plants by 30% by 2030.

Job-killing, poverty-exacerbating, electricity rate-raising, unmeasurable temperature-benefitting. And with no demonstrable technology for carbon capture and sequestration (CCS), there is no way to make coal-fired plants meet the new rule.

But these objections are just, so, you knowold school. I mean, we need nice shiny new energy technologies that dont pollute. Technologies that arent promoted by tobacco scientists like me. That make our roadways clean, Green and hi-tech. Without all of that nasty carbon pollution (sounds dirty, doesnt it?).

As some of us try to list all of the reasons why such regulations are not just a waste of time, but also damaging to human health and welfare, there is a sizeable fraction of people who are easily duped by what sounds good to them.

Carbon dioxide, contrary to what you might have learned in school many years ago, is now a pollutant. It doesn’t matter that recent warming and CO2 increases have also led to greening of the Earth since CO2 (now standing at 4 parts per 10,000 of the atmosphere) is necessary for life on Earth. No, rather than real, demonstrated benefits of more atmospheric CO2, we instead have to worry about theoretical risks of more CO2.

Ive met a whole new batch of these easily-duped people in the last few days who have left over 700 comments on my blog posts (here and here) where I pointed out that sane people shouldnt be taking perfectly good solar collectors, normally tilted toward the sun to increase energy generation and kept reasonably clean and protected, and putting them in road surfaces to be repeatedly run over by heavy, dirty cars and trucks.

Apparently, Im part of the problem rather than the solution. Part of the old, discredited way of doing things. Time to embrace the future, Dr. Roy.

So, Ive been thinking about how this new EPA power plant rule will play out.

First of all, after an obligatory EPA 1-year comment period and then even more time for the states to decide how they might want to achieve the goals of the rule, its going to be after the next presidential election before we actually see substantial changes in coal-fired generation resulting from the rule.

How convenient. Old plants are already being shuttered in favor of gas-fired plants, which are currently cheaper. So whats the point of the new regulations?

Well, what might well happen is this. Ten years down the road, global warming will turn out to be (surprise!) much weaker than predicted. Since we know the climate models that predicted much greater warming cant be wrong, it must be those new EPA regulations back in 2014 that solved the problem!

We really can control the climate system! We did somethingand it worked…retroactively!

It doesnt really matter which came first, or what-caused-what. It didnt matter for the ice core record of temperature changes coming before CO2 changes, and it wont matter for this, either.

Ice Still on Lake Superior in June!

Sunday, June 1st, 2014

Unless everything melted overnight, there is still ice on Lake Superior — and snow on the ground in Michigan — in freakin’ June.

Here’s the MODIS satellite image from early afternoon on 31 May, 2014…I’ve outlined the main areas of ice which are concentrated near the south shore of Lake Superior, mostly near Marquette and Pictured Rocks:
MODIS-Aqua-5-31-2014-ice-near-Marquette

Also from yesterday, here’s what it looked like at ground level (photo courtesy of my friends at Lake Superior Photo in Marquette):
Superior-ice-5-31-2014-Lake-Superior-Photo

And here’s another photo from yesterday, showing that not even all of the snow on the ground has melted…this from Ben Musielak, in Paradise, Michigan (I’m sure there are lots of examples of this across the Upper Peninsula in the lake effect snow belt areas):
snow-in-Paradise-5-31-2014

In case anyone needed to be told…this past winter’s persistent “polar vortex” was not that unusual, and wasn’t due to global warming climate change climate disruption.

Why Are Solar Freakin Roadways So Freakin Popular?

Saturday, May 31st, 2014

My blog traffic has been unexpectedly blowing up with visitors to my post, Solar Roadways Project: A Really Bad Idea.

The comments posted there suggest the Solar Roadways project remains very popular….it has now generated over $1.7 Million in Indiegogo.com crowd funding donations.

Now, I can only ask: Why the hell would any sane person take perfectly good solar collectors and try to embed them in roads and run over them repeatedly with heavy, dirty vehicles?

Do we take airplanes and drive them down roads? We could if we really wanted, I suppose.

I’m not the only one who sees the stupidity of the idea. Here’s a very critical post at ExtremeTech.com, and another at Jalopnik.com. And another at Equities.com.

The question that fascinates me is, why does this idea have such popular support? Here’s my theory.

We all have the experience of driving down, and walking on, roads. They are typically dirty, and hot. They represent sources of both eye pollution and real pollution.

The Solar Freakin’ Roadways project has cleverly suggested, why not replace those dirty awful road surfaces with nice, clean, hi-tech surfaces that do something useful (generate electricity)? Look how pretty it would be!:
Downtown-Sandpoint-2-small

I know I’ve wondered about all of that solar energy collected by the road, generating all that heat. But I also know that a solar heated surface does not mean you can generate much electricity. Solar domestic hot waters systems are over 90% efficient, but solar PV electricity generation is more like 15% efficient.

As discussed here, solar panels and roads that you drive on are two things that are very incompatible. There is no good reason to mix them. In fact there are many reasons to NOT mix them.

Nevertheless, the Department of Transportation awarded almost $1 million in Phase I and Phase II SBIR contracts to study the idea. Of course, we all know the government is careful about what it gives money away for, right? (I used to review SBIR proposals submitted to NASA. I wouldn’t have recommended this for funding.)

At the end of the SBIR Phase II, there is supposed to be a solar parking lot completed…which is big enough to park 4 cars on. Cars which would shade the parking lot from collecting solar energy. A parking lot which you can’t tilt toward the sun to collect more energy, as is usually done with solar panels. For close to $1 million.

Sorry, folks, but solar-based electricity is far from free. In fact, it’s very expensive, even under optimum collecting conditions. Even with subsidies and higher rates forced on consumers, less than 1 kWh of every 500 kWh generated in the U.S. comes from solar. You can have quite a bit more than that 0.2%…if you want to pay extra. After we went one week without power following the 2011 Alabama tornado outbreak, I looked into building my own system with cheap China-made collectors. I finally decided that it wasn’t worth several thousand dollars to collect enough energy to power only a refrigerator and a couple of light bulbs.

I encourage you to read the problems other people see with the idea, posted above. I agree we need to be investigating alternative sources of energy, but I can confidently predict this is an idea that is going nowhere. And as long as we keep spending money on stupid ideas, it takes that money away from funding more deserving ideas.

Spectacular Eruption of Sangeang Api Volcano (Indonesia)

Saturday, May 31st, 2014

Yesterday’s eruption of the Sangeang Api volcano in the Sundra Islands produced an ash cloud which appears to have reached the stratosphere, a necessary (but not sufficient) condition for it to temporarily cool the climate system.

A NASA MODIS satellite image of the eruption shows the ash cloud drifting southeastward toward Australia, where all flights from Darwin have been grounded:

NASA Terra MODIS imagery of the Sangeang Api eruption in Indonesia.

NASA Terra MODIS imagery of the Sangeang Api eruption in Indonesia.

Details of the eruption can be found here. This backlit photo shows the anvil-type structure which supports the view that the plume has reached the lower stratosphere (Photo credit Courtney Robba, Dunia Baru):
Sangeang-Api-eruption-1

Here’s another spectacular photo:
Sangeang-Api-eruption-2

I have not yet seen any estimates of the sulfur output from the eruption, which is what will determine its potential to reduce incoming sunlight and cause cooling. I suspect it will be nowhere near the Pinatubo eruption of 15 June 1991, which produced 20 million tons of SO2.

Yes, I Do Publish Papers, Too

Tuesday, May 27th, 2014

I don’t necessarily keep things up to date on my blog, since I don’t have George Soros underwriting my blogging efforts.

I had a comment that my publication record seems rather limited, so I’ve updated my Research Articles page with the following:

These are the ~30 most climate-relevant peer-reviewed papers I have authored or co-authored. I have many more that are weather-related or satellite remote-sensing related. I will add links as I find time.

  • Spencer, R.W., and W.D. Braswell, 2014: The role of ENSO in global ocean temperature changes during 1955-2011 simulated with a 1D climate mode. Asia-Pac. J. Atmos. Sci., 50(2), 229-237.
  • Spencer, R. W., and W. D. Braswell, 2011: On the misdiagnosis of surface temperature feedbacks from variations in Earth’s radiant energy balance. Remote Sens., 3, 1603-1613; doi:10.3390/rs3081603
  • Spencer, R. W., and W. D. Braswell, 2010: On the diagnosis of radiative feedback in the presence of unknown radiative forcing. J. Geophys. Res., 115, doi:10.1029/2009JD013371
  • Spencer, R.W., and W.D. Braswell, 2008: Potential biases in cloud feedback diagnosis: A simple model demonstration, J. Climate, 23, 5624-5628.
  • Spencer, R.W., 2008: An Inconvenient Truth: blurring the lines between science and science fiction. GeoJournal (DOI 10.1007/s10708-008-9129-9)
  • Spencer, R.W., W.D. Braswell, J.R. Christy, and J. Hnilo, 2007: Cloud and radiation budget changes associated with tropical intraseasonal oscillations. J. Geophys. Res., 9 August.
  • Christy, J.R., W.B. Norris, R.W. Spencer, and J.J. Hnilo, 2007: Tropospheric temperature change since 1979 from tropical radiosonde and satellite measurements. J. Geophys. Res., 112, D06102, 16 pp.
  • Spencer, R.W., J.R. Christy, W.D. Braswell, and W.B. Norris, 2006: Estimation of tropospheric temperature trends from MSU channels 2 and 4. J. Atmos. Ocean. Tech, 23, 417-423.
  • Ohring, G., B. Wielicki, R. Spencer, B. Emery, and R. Datla, 2005: Satellite instrument calibration for measuring global climate change. Bull. Amer. Meteor. Soc., 1303-1313.
  • Lobl, E.E., and R.W. Spencer, 2004: The Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and its products. Italian Journal of Remote Sensing, 30/31, 9-18.
  • Kawanishi, T., T. Sezai, Y. Ito, K. Imaoka, T. Takeshima, Y. Ishido, A. Shibata, M. Miura, H. Inahata, and R.W. Spencer, 2003: The Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), NASDA’s contribution to the EOS for Global Energy and Water Cycle Studies. IEEE Trans. Geosys. Rem. Sens., 41, 184-194.
  • Christy, J.R., R.W. Spencer, W.B. Norris, W.D. Braswell and D.E. Parker. 2003: Error Estimates of Version 5.0 of MSU–AMSU Bulk Atmospheric Temperatures. Journal of Atmospheric and Oceanic Technology: 20, pp. 613-629.
  • Robertson, F.R., R.W. Spencer, and D.E. Fitzjarrald, 2001: A new satellite deep convective ice index for tropical climate monitoring: Possible implications for existing oceanic precipitation datasets. Geophys. Res. Lett., 28-2, 251-254.
  • Imaoka, K., and R.W. Spencer, 2000: Diurnal variation of precipitation over the tropical oceans observed by TRMM/TMI combined with SSM/I. J. Climate, 13, 4149-4158.
  • Christy, J.R., R.W. Spencer, and W. D. Braswell, 2000: MSU tropospheric temperatures: Dataset construction and radiosonde comparisons. J. Atmos. Ocean. Tech., 17, 1153-1170.
  • Spencer, R.W., F. J. LaFontaine, T. DeFelice, and F.J. Wentz, 1998: Tropical oceanic precipitation changes after the 1991 Pinatubo Eruption. J. Atmos. Sci., 55, 1707-1713.
  • Wentz, F.J. and R.W. Spencer, 1998: SSM/I rain retrievals within a unified all-weather ocean algorithm. J. Atmos. Sci., 55, 1613-1627.
  • Christy, J.R., R.W. Spencer, and E.S. Lobl, 1998: Analysis of the merging procedure for the MSU daily temperature time series. J. Climate, 11, 2016-2041.
  • Spencer, R.W., and W.D. Braswell, 1997: How dry is the tropical free troposphere? Implications for global warming theory. Bull. Amer. Meteor. Soc., 78, 1097-1106.
  • Spencer, R.W., J.R. Christy, and N.C. Grody, 1996: Analysis of “Examination of ‘Global atmospheric temperature monitoring with satellite microwave measurements. Climatic Change, 33, 477-489.
  • Spencer, R.W., 1994: Oceanic rainfall monitoring with the microwave sounding units. Rem. Sens. Rev., 11, 153-162.
  • Spencer, R.W., 1994: Global temperature monitoring from space. Adv. Space Res., 14, (1)69-(1)75.
  • Spencer, R.W., 1993: Monitoring of global tropospheric and stratospheric temperature trends. Atlas of Satellite Observations Related to Global Change, Cambridge University Press.
  • Spencer, R.W., 1993: Global oceanic precipitation from the MSU during 1979-92 and comparisons to other climatologies. J. Climate, 6, 1301-1326.
  • Spencer, R.W., and J.R. Christy, 1993: Precision lower stratospheric temperature monitoring with the MSU: Technique, validation, and results 1979-91. J. Climate, 6, 1301-1326.
  • Spencer, R.W., and J.R. Christy, 1992a: Precision and radiosonde validation of satellite gridpoint temperature anomalies, Part I: MSU channel 2. J. Climate, 5, 847-857.
  • Spencer, R.W., and J.R. Christy, 1992b: Precision and radiosonde validation of satellite gridpoint temperature anomalies, Part II: A tropospheric retrieval and trends during 1979-90. J. Climate, 5, 858-866.
  • Spencer, R.W., J.R. Christy, and N.C. Grody, 1990: Global atmospheric temperature monitoring with satellite microwave measurements: Method and results, 1979-84. J. Climate, 3, 1111-1128.
  • Spencer, R.W., and J.R. Christy, 1990: Precise monitoring of global temperature trends from satellites. Science, 247, 1558-1562.