Monthly Archives: September 2006

The Lyman et al Paper “Recent Cooling In the Upper Ocean” Has Been Published

The paper by John M. Lyman, Josh K. Willis and Gregory C. Johnson entitled “Recent cooling of the upper ocean” has appeared in Geophysical Research Letters. This paper has already been discussed on Climate Science (see and see).

This Climate Science weblog is written to alert readers to where the data can be accessed to explore this issue further, as well as look at the latest data as it becomes available. This information is available from these sites [see, see and see].

There is also the issue as to how this important article has been covered in the media. The NASA Press release is available (see). This press release is entitled “Short-Term Ocean Cooling Suggests Global Warming ‘Speed Bump'”. An excerpt from the report states,

“The recent changes in ocean temperature run deep. A small amount of cooling was detected at the ocean’s surface, consistent with global measurements of sea-surface temperature. The maximum amount of cooling was at a depth of about 1,300 feet, but substantial cooling was still observed at 2,500 feet, and the cooling appears to extend deeper.

Lyman said the cause of the recent cooling is not yet clear. Research suggests it may be due to a net loss of heat from the Earth. ‘Further work will be necessary to solve this cooling mystery,’ he said.”

This mystery is a critical question, as it is not known if this is just a “speed bump”, or indicates that we have a poorer understanding of the climate system, even in terms of global average radiative heating, than has been advocated by the international climate assessments such as the IPCC.

The way this new research result has been communicated to the public is also quite informative with respect to the media’s perspective on the climate change issue. One news article is headlined “Short-Term Ocean Cooling Suggests Global Warming” . This is not only a self-contradiction, but scientifically incorrect. Ocean cooling indicates “global cooling”! (see)
.

A search on google shows that there is remarkably little media coverage on this observation of cooling. What there is understates the significance of the finding that over 20% of the heat gained since the mid 1950s were lost in just two years! The reason for this large negative radiative imbalance in the Earth’s climate system is a “mystery, but it certainly indicates that the multi-decadal global climate models have serious issues with their ability to accurately simulate the response of the climate system to human- and natural-climate forcings.

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New Journal of Geophysical Research Paper on Biomass Heat and Biochemical Energy Associated With Vegetation Processes – Two Important Largely Neglected Climate Processes

An important new paper is in press in the Journal of Geophysical Research entitled “Influences of biomass heat and biochemical energy storages on the land surface fluxes and radiative temperature” [the paper is not yet available online]. The authors are Lianhong Gu, Tilden Meyers, Stephen G. Pallardy, Paul J. Hanson, Bai Yang, Mark Heuer, Kevin P. Hosman, Qing Liu, Jeffery S. Riggs, Dan Sluss, and Stan D. Wullschleger.

This very original paper identifies two generally ignored climate processes which have significant effects on daily, seasonal and longer term temperature variations and trends. The abstract reads,

“The interest of this study was to develop an initial assessment on the potential importance of biomass heat and biochemical energy storages for land – atmosphere interactions, an issue that has been largely neglected so far. We conducted flux tower observations and model simulations at a temperate deciduous forest site in central Missouri in the summer of 2004. The model used was the comprehensive terrestrial ecosystem Fluxes And Pools Integrated Simulator (FAPIS). We first examined FAPIS performance by testing its predictions with and without the representation of biomass energy storages against measurements of surface energy and CO2 fluxes. We then evaluated the magnitudes and temporal patterns of the biomass energy storages calculated by FAPIS. Finally, the effects of biomass energy storages on land – atmosphere exchanges of sensible and latent heat fluxes and variations of land surface radiative temperature were investigated by contrasting FAPIS simulations with and without these storage terms. We found that with the representation of the two biomass energy storage terms, FAPIS predictions agreed with flux tower measurements fairly well; without the representation, however, FAPIS performance deteriorated for all predicted surface energy flux terms although the effect on the predicted CO2 flux was minimal. In addition, we found that the biomass heat storage and biochemical energy storage had clear diurnal patterns with typical ranges from -50 to 50 and -3 to 20 Wm-2, respectively; these typical ranges were exceeded substantially when there were sudden changes in atmospheric conditions. Furthermore, FAPIS simulations without the energy storages produced larger sensible and latent heat fluxes during the day but smaller fluxes (more negative values) at night as compared with simulations with the energy storages. Similarly, without-storage simulations had higher surface radiative temperature during the day but lower radiative temperature at night, indicating that the biomass energy storages act to dampen the diurnal temperature range. From these simulation results, we concluded that biomass heat and biochemical energy storages are an integral and substantial part of the surface energy budget and play a role in modulating land surface temperatures and must be considered in studies of land atmosphere interactions and climate modeling.”

Excerpts from the conclusions read,

“Biomass heat and biochemical energy storages are an integral and substantial part of the surface energy budget at this Missouri Ozark forest site…….. Averaged over the simulation period (four summer months) in our study, the biochemical energy storage is about 4.1±0.1 Wm-2…….. For comparison, the radiative forcing of greenhouse gases (CO2, CH4, N2O, and halocarbons together) is about 2.43 Wm-2 above the pre-industrial level [IPCC, 2001]; this value could be smaller in the current atmosphere since some of the earlier imbalance presumably has already warmed the climate system. Thus at least at regional scales, biochemical energy storage is on the same order of magnitude as the radiative forcing of atmospheric greenhouse gases. Therefore, for long-term climate system modeling which includes vegetation processes, biochemical energy storage could be important, particularly at regional scales……Biomass heat and biochemical energy storages act to reduce daytime surface temperature and increase nighttime temperature, thus leading to decreased DTR [Diurnal Temperature Range]…….We emphasize that our estimate of influences of biomass heat and biochemical energy storages on DTR (0.5 C) is conservative because we did not consider the feedback from changes in biomass temperature on the atmospheric forcing temperature. If this feedback is considered, the effect of biomass heat and biochemical energy storages on DTR might be even larger……

Finally, biomass distribution is spatially heterogeneous, which means that biomass heat and biochemical energy storages must be also spatially heterogeneous. This heterogeneity is in essence a form of gradient radiative forcing [Matsui and Pielke, 2006]. In conjunction with spatial variations in evapotranspiration, albedo, and surface roughness associated with vegetation cover, it can influence horizontal pressure gradients and mesoscale atmospheric circulations and therefore regional climates. More studies are needed in this area.”

Climate Science will alert readers when the paper becomes available online.

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Overview of The 4th Annual SORCE Meeting: Earth’s Radiative Budget – Part II

This weblog continues the posting of further excerpts from the 4th Annual SORCE Meeting: Earth’s Radiative Budget”. I was informed yesterday that most of the powerpoint slides from the talks will be available within a few weeks, and I will post when they are.

One of the most presented slide at the meeting was the 1997 Kiehl and Trenberth figure on the components of the average Earth’s energy budget (see page 16 of the 2005 National Research Council Report for an illustration of this figure). There were a number of talks that indicated the specific values within the figure need to be corrected by several Watts per meter squared. More on this subject when the powerpoint slides become available.

On the radiation budget, Bill Collins presented evidence on significant problems with the radiative parameterizations used in the global climate models. He stated that none of the IPCC models have methane and nitrous oxide [with repect to solar radiative forcing]. Also, that the largest [radiative] forcing bias occurs at the surface. His abstract reads in part,

“assessment by the Intergovernmental Panel on Climate Change (IPCC). Several lines of evidence from this evaluation indicate that there are substantial discrepancies among the AOGCMs in the ensemble and between the AOGCMs and reference line-by-line (LBL) In some cases this is because the AOGCMs neglect particular absorbers, while in others due to the methods for modeling the radiative processes. These differences have important implications for interpreting variations in forcing and response across the multi-model ensemble of AOGCM simulations assembled for the IPCC fourth assessment report (AR4). We conclude by presenting new mathematical methods for improving the accuracy of the radiative parameterizations in global models.”

Mark Weber stated that the stratosphere has become drier. In his abstract he wrote,

“After the middle 1990s, ozone levels have been increasing particularly in the northern hemisphere after a long-term downward trend.”

and that,

” Since the direct radiation impact on lower stratospheric ozone (as represented by total ozone) is rather small, solar irradiance variability must alter ozone via dynamical feedbacks as will be discussed in this talk.”

Jose Rial presented a very interesting talk that demonstrated how a slowly varying external [in his case natural] forcing can produce rapid and sudden major transitions in climate. His study will be available soon in a paper [Rial and Young 2006]. An important conclusion from his study is that the Milankovitch cycle is clearly a regional climate forcing effect, not only a global average forcing. His abstract states in part,

The modeling results further indicate that solar forcing organizes the free oscillations to form the (as yet unexplained) characteristic pattern of abrupt climate over the last ice age. No North Atlantic fresh water balance perturbations were necessary produce these model results; no external forcing other than the Milankovitch summer insolation was used.”.

Additional notes from this excellent SORCE meeting will be presented on Climate Science in upcoming posts.

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Further Comments on the Denver Post article “Global Warming?”

In order to further correct the Denver Post news article entitled “Global Warming”, I am commenting today about another aspect of that report.

The text included the statements,

“Chris Folland, a researcher at Britain’s Hadley Centre for Climate Prediction, said the data points in one direction. ‘We’ve shown that the climate change is a true thing,” he said. “We’ve done that with global averages, since that was easiest.”The American government might not agree,’ Folland said. ‘Most American scientists do.’â€?

This quote (by a very respected scientist) makes the mistake of assuming that “climate changeâ€? is equivalent to the change in climate caused by the radiative effect of CO2. This error is repeatedly made in the news media, but as reported in the 2005 National Research Council report (which has been universally ignored by the media) and on Climate Science (see), climate variability and change involves a diverse range of human- and natural-climate forcings. Informed readers will recognize that the news article is not presenting a balanced view when such an error is committed

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Overview of The 4th Annual SORCE Meeting: Earth’s Radiative Budget

I attended the 4th Annual SORCE Meeting: “Earth’s Radiative Budgetâ€?, and was impressed by the research being conducted on the role of solar forcing on the Earth’s climate. This group of scientists are clearly represent the world leaders in assessing solar forcing of the Earth’s climate system. Last week I presented extracts from several of the talks, and here I will present excerpts of my notes for the meeting.

The total solar irradiance in near real time can be obtained from several websites (see). An interesting finding at the meeting is that the “solar constantâ€? value used, based on a multi-year time average is slightly smaller than is typically used and is 1361 Watts per meter squared. This value does vary over time in several interesting ways (see and see). For example, In October 2003 there was a sharp drop in total solar irradiance due to the passage of several large sunspots across the face of the Sun. When the surface of the Sun is dominated by plages, an increase in total solar irradiance occurs. Over the period since early 2004, there has been a small decrease up to the present.

The solar spectrum also varies in time (see). Several presentations discussed the significance of the observed variations in the solar spectrum. Jerry Harder stated, for example, that the

“greatest absolute variability occurs in mid visible (direct)â€? solar radiation and that the “relative uncertainty in solar forcing is very large and must be reduced in order to separate natural and anthropogenic forcingâ€?.

In terms of how the climate system responds to solar forcing, Robert Cahalan concluded in this talk that using “cloud fraction for radiation [effects] is an inadequate ‘band aid’â€? and that “none of the 1-D schemes work.â€?

His abstract also presents this conclusion where he wrote, “ The interaction of clouds with solar and terrestrial radiation is one of the most important topics of climate research. Because of the complexity of clouds, only full three-dimensional (3D) treatment of this interaction can provide answers to many climate and remote sensing problems…â€?

Another valuable source of solar forcing data is the Geostationary Radiation Budget Experiment (GERB), which was discussed by Steven Dewitte. This is new data (and became available for public use in March; see) will further expand our understanding of solar forcing. The animations from these satellite data are very informative (see), and show the complex regional variations in solar forcing and in the total radiation budget.

Roger Davies presented time series of deseasonalized 10-day and annual anomalies related to the TOA radiation budget analyzed from MISR measurements, from early 2000 to the present. He concludes, as stated in his abstract that,

The biggest interannual global anomalies observed by MISR that affect the top of atmosphere radiative budget appear to be those in the effective cloud height. These show interesting decreases through 2005, averaging about 10m/yr. On a regional basis, the largest signal occurs systematically in the InterTropical Convergence Zone, associated with a reduction in high cloud fraction. The 2006 data appear, however, to be showing an increase in height.”

MISR is the “Multiangle Imaging SpectroRadiometerâ€? which images Earth’s climate system simultaneously at 9 different angles;). His analysis of the MISR satellite data further illustrates the significant temporal and regional variability in climate data which is not accurately simulated (or understood) using climate models.

Judith Lean’s presentation entitled “Solar Radiative Forcingâ€? updated our understanding of the magnitude of total solar irradiance. In her abstract, she stated,
“Simulations of the evolution of magnetic flux on the Sun’s surface suggest a secular total irradiance increase of order 0.08% during the past three centuries, which is less then the increase of 0.2-0.4% inferred from earlier studies of variations of Sun-like stars and cosmogenic isotopes.â€?

The discussion of the SORCE talks will continue this week.

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News Article Quote Attributed To Jim Hansen

There was a news article today in the Denver Post entitled “Global Warming?”. My views are clearly articulated on Climate Science (see), but unfortunately, the article does not clearly distinguish that there are a diversity of views among climate scientists on the role of human- and natural- climate forcings. The article also has errors; for example, the statement attributed to me that

“Man-made changes to the land, in addition to about 30 other greenhouse gases – some man-made, some natural – may play an even a bigger role, he said.”

is in error. I stated that besides land use changes, the input into the climate system of natural- and human-aerosols have a range of effects on the climate system, which may exert larger effects on the global climate system than the radiative effect of the human input of CO2. We have documented this conclusion, for example, in our peer-reviewed paper “Measurement-based estimation of the spatial gradient of aerosol radiative forcing”. This does not mean we should not seek to reduce the human input of CO2 into the atmosphere, but it does mean that controlling CO2 emissions alone only addresses a fraction of the human alteration of the climate system. Of most concern to those who value courteous scientific debate, however, is the quote from Jim Hansen. It reads


“Some of this noise won’t stop until some of these scientists are dead,” said James Hansen, head of the Goddard Institute for Space Studies in New York City, and among the first to sound the alarm over climate change.”

Regardless as to your perspective on climate change, this callous statement from a federal administrator who is very visible in the climate science debate should be strongly repudiated by everyone who accepts that the debate should be about the science. I invite Dr. Hansen to expand on, clarify, or correct the comment that he made for this news article.

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A Presentation by Peter Pilewskie at the SORCE Meeting entitled “An Overview of the Radiation Budget in the Lower Atmosphere”

On Wednesday at the SORCE meeting a presentation was given by Peter Pilewskie entitled ” An Overview of the Radiation Budget in the Lower Atmosphere”. The abstract reads,

“The radiation budget at the top-of-atmosphere is relatively well understood from satellite observations such as those made by Nimbus-7, ERBE, CERES and SORCE, especially when compared to that at surface and lower atmosphere. For example, the accuracy and annual variability in total solar irradiance is known to within a few tenths of a percent and for top of the atmosphere albedo, about 1%. By contrast, the range of estimates for the surface radiative energy budget vary by more than 10% between satellite remote sensing and model simulations, and it is difficult to quantify the absolute uncertainties associated with the individual terms. Using results from a number of recent airborne field campaigns and from satellite observations, we will assess the current state of knowledge of the lower atmosphere radiative energy budget with particular attention on where solar radiative energy is deposited in the system. We also
present simulations of variability in direct solar heating of the lower atmosphere in response to varying levels of solar activity as measured by the SORCE Solar Irradiance Monitor (SIM).”

The statement that

“…the range of estimates for the surface radiative energy budget vary by more than 10% between satellite remote sensing and model simulations, and it is difficult to quantify the absolute uncertainties associated with the individual terms..”

is a candid assessment of the limited accuracy that is possible with the multi-decadal global climate models.

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