Monthly Archives: July 2009

New Paper “Surface Temperature Variations In East Africa And Possible Causes” By Christy Et Al. 2009

As posted on Watts Up With That, ICECAP and Climate Audit, there is an excellent new paper on the issue of surface temperature trends. The paper is

Christy, J.R., W.B. Norris, and R.T. McNider, 2009: Surface Temperature Variations in East Africa and Possible Causes. J. Climate, 22, 3342–3356.

The abstract reads

“Surface temperatures have been observed in East Africa for more than 100 yr, but heretofore have not been subject to a rigorous climate analysis. To pursue this goal monthly averages of maximum (TMax), minimum (TMin), and mean (TMean) temperatures were obtained for Kenya and Tanzania from several sources. After the data were organized into time series for specific sites (60 in Kenya and 58 in Tanzania), the series were adjusted for break points and merged into individual gridcell squares of 1.25°, 2.5°, and 5.0°.

Results for the most data-rich 5° cell, which includes Nairobi, Mount Kilimanjaro, and Mount Kenya, indicate that since 1905, and even recently, the trend of TMax is not significantly different from zero. However, TMin results suggest an accelerating temperature rise.

Uncertainty estimates indicate that the trend of the difference time series (TMax – TMin) is significantly less than zero for 1946-2004, the period with the highest density of observations. This trend difference continues in the most recent period (1979-2004), in contrast with findings in recent periods for global datasets, which generally have sparse coverage of East Africa.

The differences between TMax and TMin trends, especially recently, may reflect a response to complex changes in the boundary layer dynamics; TMax represents the significantly greater daytime vertical connection to the deep atmosphere, whereas TMin often represents only a shallow layer whose temperature is more dependent on the turbulent state than on the temperature aloft.

Because the turbulent state in the stable boundary layer is highly dependent on local land use and perhaps locally produced aerosols, the significant human development of the surface may be responsible for the rising TMin while having little impact on TMax in East Africa. This indicates that time series of TMax and TMin should become separate variables in the study of long-term changes.”

This an excellent research contribution and adds to the concern with respect to using the surface temperature trends as the climate metric to monitor and predict global average warming and cooling that we overviewed in our paper

Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229

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New Paper “How Will Earth’s Surface Temperature Change in Future Decades?” By Lean and Rind 2009

There is a new paper that examines (and forecasts) the role of solar forcing in climate system warming and cooling.

 It is

Lean, J. L., and D. H. Rind (2009): How Will Earth’s Surface Temperature Change in Future Decades?,
Geophys. Res. Lett., doi:10.1029/2009GL038932, in press. (accepted 9 July 2009).

the abstract reads

“Reliable forecasts of climate change in the immediate future are difficult, especially on regional scales, where natural climate variations may amplify or mitigate anthropogenic warming in ways that numerical models capture poorly. By decomposing recent observed surface temperatures into components associated with ENSO, volcanic and solar activity, and anthropogenic influences, we anticipate global and regional changes in the next two decades. From 2009 to 2014, projected rises in anthropogenic influences and solar irradiance will increase global surface temperature 0.15±0.03 C, at a rate 50% greater than predicted by IPCC. But as a result of declining solar activity in the subsequent five years, average temperature in 2019 is only 0.03±0.01 C warmer than in 2014. This lack of overall warming is analogous to the period from 2002 to 2008 when decreasing solar irradiance also countered much of the anthropogenic warming. We further illustrate how a major volcanic eruption and a super ENSO would modify our global and regional temperature projections.”

in their paper, with respect to their forecasts, they write

“The major assumption associated with our forecasts is that ‘past is prologue’; climate will continue to respond in the future to the same factors that have influenced it in the recent past and the response will continue to be linear over the next several decades.”

I have worked with Judith Lean and respect her scientific credentials. I respect also that she has placed her forecast in print and it is not for decades into the future, but is for a reasonably short enough time in the future to verify. I would have preferred, of course, that she use upper ocean heat content in Joules rather than the global surface temperature trend, which is a very poor metric to quantify regional and global warming and cooling (e.g. see). Nonetheless,  all of us should follow the skill she achieves in the coming years.

Their new paper conflicts with the new paper which concludes that solar warming has been negligible since 1980.

Benestad, R. E., and G. A. Schmidt (2009), Solar trends and global warming, J. Geophys. Res., 114, D14101, doi:10.1029/ 2008JD011639.

 whose abstract reads

“We use a suite of global climate model simulations for the 20th century to assess the contribution of solar forcing to the past trends in the global mean temperature. In particular, we examine how robust different published methodologies are at detecting and attributing solar-related climate change in the presence of intrinsic climate variability and multiple forcings. We demonstrate that naive application of linear analytical methods such as regression gives nonrobust results. We also demonstrate that the methodologies used by Scafetta and West (2005, 2006a, 2006b, 2007, 2008) are not robust to these same factors and that their error bars are significantly larger than reported. Our analysis shows that the most likely contribution from solar forcing a global warming is 7 ± 1% for the 20th century and is negligible for warming since 1980.”

The Benestad, R. E., and G. A. Schmidt 2009 and Lean, J. L., and D. H. Rind 2009 cannot both be correct in their conclusion regarding the magnitude of solar forcing on the Earth’s climate. They could both even be wrong based on such studies as

How Do Climate Models Work? by Roy Spencer

and

Compo,G.P., and P.D. Sardeshmukh, 2008: Oceanic influences on recent continental warming. Climate Dynamics.

with respect to the role of circulation changes in the magnitude of global warming and cooling.

Finally, both Benestad, R. E., and G. A. Schmidt 2009 and Lean, J. L., and D. H. Rind 2009 used the global average surface temperature trend to discuss the issue of global warming. They more appropriately should use the accumulation of Joules in the upper ocean as the diagnostic (e.g. see which the GISS group continues to ignore).

 

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Biased Criticism of Anthony Watts For His Report “Is The U.S. Surface Temperature Record Reliable?”

There is a You Tube video by Peter Sinclar titled “Climate Denial Crock of the Week” which ridicules the important contribution of Anthony Watts in identifying poor siting issues with the US Historical Climate Network (see his report). The video is clearly a biased presentation of what Anthony has accomplished, even resorting to the absurd connection of climate to how the health issues of tobacco were reported.  The video fails to recognize that the National Climate Data Center (NCDC) invited Anthony to present his work in Asheville, and recently, one of the NCDC scientists invited him to co-author a research paper with him.

I will report if NCDC refutes this personal attack against a well respected colleague who has provided a much needed analysis to the climate science community. Stay tuned also for at least two peer reviewed papers which are quantitatively analyzing, using Anthony’s data, the impact of the poor sitings of the HCN sites on the long term surface temperature trends and anomalies.

 

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Announcement Of Second Edition “The Simple Science of Flight: From Insects to Jumbo Jets (Revised and Expanded Edition)” by Henk Tennekes

Henk Tennekes has a second edition of his book, and I am pleased to announce it on my weblog. Following the announcement, Henk has also provide a review of another book that he has completed.

“The Simple Science of Flight: From Insects to Jumbo Jets (Revised and Expanded Edition)” by Henk Tennekes

From the smallest gnat to the largest aircraft, all things that fly obey the same aerodynamic principles. In The Simple Science of Flight, Henk Tennekes investigates just how machines and creatures fly: what size wings they need, how much energy is required for their journeys, how they cross deserts and oceans, how they take off, climb, and soar. Fascinated by the similarities between nature and technology, Tennekes offers an introduction to flight that teaches by association. Swans and Boeings differ in numerous ways, but they follow the same aerodynamic principles. Biological evolution and its technical counterpart exhibit exciting parallels. What makes some airplanes successful and others misfits? Why does the Boeing 747 endure but the Concorde now seem a fluke? Tennekes explains the science of flight through comparisons, examples, equations, and anecdotes.

The new edition of this popular book has been thoroughly revised and much expanded. Highlights of the new material include a description of the incredible performance of bar-tailed godwits (7,000 miles nonstop from Alaska to New Zealand), an analysis of the convergence of modern jetliners (from both Boeing and Airbus), a discussion of the metabolization of energy featuring Lance Armstrong, a novel treatment of the aerodynamics of drag and trailing vortices, and an emphasis throughout on evolution, in nature and in engineering. Tennekes draws on new evidence on bird migration, new wind-tunnel studies, and data on new airliners. And his analysis of the relative efficiency of planes, trains, and automobiles is newly relevant. (On a cost-per-seat scale, a 747 is more efficient than a passenger car.)

About the Author
Henk Tennekes is Director of Research Emeritus at the Royal Netherlands Meteorological Institute, Emeritus Professor of Meteorology at the Free University (VU) in Amsterdam, and Emeritus Professor of Aerospace Engineering at Pennsylvania State University. He is the coauthor of A First Course in Turbulence (MIT Press, 1972).

Endorsements
“This was a great little book when it came out in its original edition; this new version is even better, as it contains both Henk’s homage to his favorite flying machine (Boeing 747) and explanations based on some of the unexpected results of recent experiments with bird flight (including a phenomenal gliding jackdaw). Read it, then watch the birds and planes, and then dip into it again and again.”
Vaclav Smil, University of Manitoba, and author of Global Catastrophes and Trends

One gets a fine sense of how so much of aircraft design-whether by humans or by evolution-depends on size and mission. This new version of The Simple Science of Flight broadens the enlightenment that so many of us found appealing in its predecessor. It yields even more of that satisfying ‘now I understand what’s happening’ rather than the usual ‘how brilliant those designers must be.’ And I know of no book that derives such an awesome wealth of insight from such simple quantification. Beyond being informative, it provides pleasant reading-for any one who travels by air, watches animals fly, or dreams of learning to fly.”
Steven Vogel, James B. Duke Professor, Emeritus, Duke University

Review By Henk Tennekes

Alexander’s Jumbo Jets

Alexander, David E. 2009. Why Don’t Jumbo Jets Flap Their Wings? Rutgers University Press. ISBN 978-0-8135-4479-3, hardback, 278 pp, figures. Price 28 euro.

David Alexander is the author of Nature’s Flyers (2002), a deservedly popular introductory biology text on flying insects, bats, and birds. Rutgers University Press recently released Alexander’s second book, Why Don’t Jumbo Jets Flap Their Wings? The new book is written for the general public, not primarily for professional  biologists and engineers. “Science writing at its best,” says professor Sankar Chatterjee of Texas Tech, and I agree. This book is intended for birdwatchers who, like me, are fascinated by everything that flies, natural or technical.

In ten easygoing and enjoyable chapters, focussed on the differences between flying animals and airplanes, Alexander deals successively with evolution, lift, power, manoeuverability, the need for tail surfaces, flight instruments, soaring, hovering, aerial combat, and ornithopters. One major point of divergence: muscles excel in back-and-forth motion such as wing flapping, aircraft engines base their functionality on rotary motion. As far as manoeuverability is concerned, the sophisticated interaction between their nervous system and their flying apparatus that insects, birds, and bats are capable of is a source of envy for pilots and aircraft designers. Bats have no need for tails because their nervous systems are so well integrated. The chapter on predation and aerial combat is a real treat. I knew of course that Eleanora’s falcon feeds on migrating passerines during its breeding season, but I didn’t know that the greater noctule bat does so too, taking advantage of the fact that most passerines are nocturnal migrants. And I was thrilled to learn that some insect-hawking bats “use their wings as tennis rackets, deftly tapping an insect to deflect it into their mouths.” Alexander deals at length with ornithopters. Considering the title of his book, he has to. Flapping wings are not the way to go when size and weight become too large. A jumbo jet does not flap its wings because the hinges, engines, and linkage systems  needed to power it would be far too heavy. Also, flapping flight is like a roller-coaster ride, because the upstroke of the wings delivers little or no lift, so that the body falls until lifted again by the downstroke. All passengers riding a flapping jumbo jet would be airsick for the entire ride. On the other hand, flapping is the preferred solution when sizes are small. Miniature rotary engines cannot compete in that technological niche.

Alexander compares the slow evolution of flight in Nature with the rapid evolution of flight in human technology. “Natural selection works on a time scale of hundreds of thousands or even millions of years. When a one-in-a-million beneficial change does occur, it tends to spread through the species. Changes that might take hundreds of thousands of years of animal evolution can take place in less than a decade of technological development.” He recognizes other differences, too. Animals co-evolve with their environment, human technology often changes the environment. Wheels are unsuitable in rough terrain; the worldwide success of automobiles is due in no small part to the concurrent evolution of highway systems. I feel Alexander tends to underestimate how often technological breakthroughs resemble random genetic mutations in Nature, which, as he correctly states, are “almost always detrimental.” Airplane encyclopedias are filled with planes that can fairly be labeled as evolutionary misfits, as designs that did not live up to their designers’ dreams and disappeared within ten or twenty years. Some, like Howard Hughes’ Spruce Goose made just one brief hop. Others, like the supersonic Concorde, are evolutionary mutants, products of the overheated preoccupations of their designers and sponsors. Even the ultimate aeronautical dream, human-powered flight, lovingly described in Alexander’s book, did not last long. Planes powered by human athletes are unfit for everyday use; they are in fact extinct now.

In the epilogue, Alexander returns to the central theme of his book: how flying animals differ from flying machines. “In the end, what truly sets birds apart from airplanes is versatility versus efficiency. Engineers design airplanes to carry out particular tasks, so airplanes tend to be quite specialized. A Boeing 747 can haul huge loads of passengers over enormous distances, but that is basically all it can do. Animals cannot afford to be so specialized.” I agree, but not without some reservations. Albatrosses are specialized in so-called dynamic soaring in wide-open environments with a uniform wind regime, bar-tailed godwits perform 11,000 km nonstop flights across the Pacific Ocean but have a barely adequate immune system, bats use very sophisticated echo location equipment that is useless in daylight because insects can easily take evasive action, penguins use their wings exclusively for under-water swimming, and so on. And some kinds of airplanes, like the Piper Cub and the Cessna 172, are supreme generalists, much like sparrows and starlings. In fact, the early success of the Piper Cub was based on its usefulness for the US Army: it could land and take off most anywhere, rough terrain or not. The task of evaluating the differences between biological evolution and its technological counterpart is far from being finished, but in Jumbo Jets Alexander makes a giant step in the right direction.

Henk Tennekes

 

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Article On Arctic Sea Ice In The NASA Publication “The Earth Observer”

There is a useful update of Arctic sea ice on pages 19-20  in the May-June 2009 issue of the NASA publication “The Earth Observer”  by Walt Meir and Stephanie Renfrow  titled “Arctic Sea Ice News & Analysis: Arctic Sea Ice Younger, Thinner as Melt Season Begins”.

This informative article includes the text

“How vulnerable is the ice cover as we go into the summer melt season? To answer this question, scientists also need information about ice thickness. Indications of winter ice thickness, commonly derived from ice age estimates, reveal that the ice is thinner than average, suggesting that it is more susceptible to melting away during the coming summer.”

“While ice older than two years reached record lows, the fraction of second-year sea ice increased compared to last winter. Some of this second-year ice will survive the summer melt season to replenish the Arctic’s store of older ice; however, in recent years less young ice has made it through the summer. To restore the amount of older ice to pre-2000 levels, large amounts of this young ice would need to endure through summer for several years in a row.

But conditions may not always favor the survival of second-year and older ice. Each winter, winds and ocean currents move some sea ice out of the Arctic ocean. This winter, some second-year ice survived the 2008 melt season only to be pushed out of the Arctic by strong winter winds. Since the end of September 2008, 150,000 mi2 (390,000 km2) of second-year ice and 73,000 mi2 (190,000 km2) of older (more than two years old) ice moved out of the Arctic (Maslanik et al., 2007; Fowler et al., 2004).”

The entire article is worth reading.

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New Paper Accepted “Impacts Of Land Cover On Temperature Trends Over The Continental United States: Assessment Using The North American Regional Reanalysis” By Fall Et Al 2009

We have a new paper accepted. It is

Fall, S., D. Niyogi, A. Gluhovsky, R. A. Pielke Sr., E. Kalnay, and G. Rochon, 2009: Impacts of land us land cover on temperature trends over the continental United States: Assessment using the North American Regional Reanalysis. Int. J. Climatol., accepted.

This paper (and other such publications) avoids systematic biases in using reanalyses with respect to the the 2m temperatures that were identified by the Pitman and Perkins (2009) paper (see, see and see). As explained by Eugenia Kalnay in an e-mail to me last week, working with anomalies eliminates those types of bias in the 2m temperatures.

The abstract of the new Fall et al paper is

“We investigate the sensitivity of surface temperature trends to land use land cover change (LULC) over the conterminous United States (CONUS) using the observation minus reanalysis (OMR) approach. We estimated the OMR trends for the 1979-2003 period from the US Historical Climate Network (USHCN), and the NCEP-NCAR North American Regional Reanalysis (NARR). We used a new mean square differences (MSDs) based assessment for the comparisons between temperature anomalies from observations and interpolated reanalysis data. Trends of monthly mean temperature anomalies show a strong agreement, especially between adjusted USHCN and NARR (r = 0.9 on average) and demonstrate that NARR captures the climate variability at different time scales. OMR trend results suggest that unlike findings from studies based on the global reanalysis (NCEP/NCAR reanalysis), NARR often has a larger warming trend than adjusted observations (on average, 0.28 and 0.27ºC/decade respectively). OMR trends were found to be sensitive to land cover types. We analyzed decadal OMR trends as a function of land types using the Advanced Very High Resolution Radiometer (AVHRR) and new National Land Cover Database (NLCD) 1992-2001 Retrofit Land Cover Change. Results indicate that when the dynamic nature of LULC is taken into account, the magnitude of OMR trends is larger than the ones derived from a “static” LULC dataset and land use conversion often results in more warming than cooling. Overall, our results confirm the robustness of the OMR method for detecting nonclimatic changes at the station level, evaluating the impacts of adjustments performed on raw observations, and demonstrating sensitivity to LULC changes at local and regional scales. Since the majority of warming trends that we identify can be explained on the basis of LULC changes, we suggest that in addition to considering the greenhouse gases driven radiative forcings, multi-decadal and longer climate models simulations must further include LULC changes.”

Text in the conclusion includes

“Since the majority of warming trends that we identify can be explained on the basis of land use/land cover changes, we suggest that in addition to considering the well-mixed greenhouse gases and aerosol driven radiative forcings, multi-decadal and longer climate models simulations must further include land cover/land use changes. In terms of using long term surface temperature records as a metric to monitor climate change, there also needs to be further work to separate the local microclimate and non-climate station effects from the regional land use/land cover change effects on surface temperatures.”

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Comments On The Current Record Global Average Lower TroposphereTemperatures

In the last couple of weeks, the onset of the El Niño, that was discussed on in my weblog on July 11 2009 would appear to be a possible explanation for the sudden increase in lower tropospheric temperatures to a record level (e.g. see the latest tropospheric temperature data at Daily Earth Temperatures from Satellite). This sudden warming is also discussed on other websites (see and see).

The current and recent anomalies at 500 mb (as representative of the tropospheric temperatures) are provided by the excellent NOAA analyses at

http://www.cpc.noaa.gov/products/intraseasonal/z500_nh_anim.shtml

http://www.cpc.noaa.gov/products/intraseasonal/z500_sh_anim.shtml

The location for the sudden warming (in the global average tropospheric temperatures as reported from the AMSU data) at 500 mb in the Northern Hemisphere is not obvious, however, except perhaps for a large area with weak positive anomalies in the lower latitudes. There is some warming in the El Niño area, but it is relatively small.  In the lower latitude eastern hemisphere In the southern hemisphere, there is a strong warm anomaly near Antarctica. Maybe that is part of the reason for major region for the large positive AMSU temperature value.

This record event is an effective test of two hypotheses.

Hypothesis #1: Roy Spencer’s  hypothesis on the role of circulation patterns in global warming (e.g. see) might explain most or all of the current anomaly since it clearly is spatially very variable, and its onset was so sudden. If the lower atmosphere cools again to its long term average or lower, this would support Roy’s viewpoint.

Hypothesis #2:  Alternatively, if the large anomaly persists, it will support the claims by the IPCC and others (e.g. see Cool Spells Normal in Warming World) that well-mixed greenhouse gas warming is the dominate climate forcing in the coming decades and is again causing global warming after the interruption of the last few years.

Only time will tell which is correct, however, we now have short term information to test the two hypotheses. The results of this real world test will certainly influence my viewpoint on climate science.

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