Monthly Archives: August 2009

Does Gavin Schmidt Understand Boundary Layer Physics?

I want to thank Bryan Sralla for alerting me to the comment by Gavin Schmidt on Real Climate  regarding  our papers 

Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr., J.R. Christy, and R.T. McNider, 2009: An alternative explanation for differential temperature trends at the surface and in the lower troposphere. J. Geophys. Res., in press

and

Mahmood, R., R.A. Pielke Sr., K.G. Hubbard, D. Niyogi, G. Bonan, P. Lawrence, B. Baker, R. McNider, C. McAlpine, A. Etter, S. Gameda, B. Qian, A. Carleton, A. Beltran-Przekurat, T. Chase, A.I. Quintanar, J.O. Adegoke, S. Vezhapparambu, G. Conner, S. Asefi, E. Sertel, D.R. Legates, Y. Wu, R. Hale, O.W. Frauenfeld, A. Watts, M. Shepherd, C. Mitra, V.G. Anantharaj, S. Fall,R. Lund, A. Nordfelt, P. Blanken, J. Du, H.-I. Chang, R. Leeper, U.S. Nair, S. Dobler, R. Deo, and J. Syktus, 2009: Impacts of land use land cover change on climate and future research priorities. Bull. Amer. Meteor. Soc., in press.

The questions on Real Climate by Paul Klemencic and Gavin’s comment are reproduced below along with my responses.

 FROM REAL CLIMATE

Paul Klemencic says:

Paul Klemencic Question #1: Since this post was set up to discuss how to critique a scientific paper, I wonder whether an example from a paper currently in publication might be interesting. The paper accepted by Bulletin of the American Meteorological Society is “Impacts of Land Use Land Cover Change on Climate and Future Research Priorities” by Rezaul Mahmood, Roger Pielke Sr., et. al. A copy of the paper is here: http://www.climatesci.org/publications/pdf/R-323.pdf

One of the key findings seems to summarized in this passage:

“The stable nocturnal boundary layer does not measure the heat content in a large part of the atmosphere where the greenhouse signal should be the largest (Lin et al. 2007; Pielke et al. 2007a). Because of nonlinearities in some parameters of the stable boundary layer (McNider et al. 1995), minimum temperature is highly sensitive to slight changes in cloud cover, greenhouse gases, and other radiative forcings. However, this sensitivity is reflective of a change in the turbulent state of the atmosphere and a redistribution of heat not a change in the heat content of the atmosphere (Walters et al. 2007). Using the Lin et al. (2007) observational results, a conservative estimate of the warm bias resulting from measuring the temperature from a single level near the ground is around 0.21°C per decade (with the nighttime minimum temperature contributing a large part of this bias). Since land covers about 29% of the Earth’s surface, extrapolating this warm bias could explain about 30% of the IPCC estimate of global warming. In other words, consideration of the bias in temperature could reduce the IPCC trend to about 0.14°C per decade; still a warming, but not as large as indicated by the IPCC. ”

A couple of quick questions on this result:

1. Is it fair to conclude that every one of the very large number of temperature measurements made on the land would be impacted by a surface boundary layer? Can a direct linear extrapolation be used to estimate the warming bias, as was done in this paper?

[Gavin Schmidt Response: As is being discussed in a number of places, there is a strong possibility of misunderstanding these statements. Changes in the BL structure for whatever reason do not cause the surface temperature trend to be wrong in any respect. If however you wanted to calculate the total heat content trend of the atmosphere (something which has not heretofore been a big requirement), then you would want to take the vertical profile changes into account (and not just in the boundary layer). If however, you are trying to compare observed surface trends to a model then you'd not have to make any corrections since a perfect model would have exactly this same behaviour. - gavin]

Roger A. Pielke Sr. Comment:

Our papers do not indicate that the measurement of the temperature is incorrect. It is the interpretation of the 2m temperatures in terms of the heat content trend above the surface that is the issue. Gavin actually agrees with this perspective, but then ignores its significance.  The use of a global average surface temperature trend to diagnose climate system heat changes introduces a bias in the magnitude of the heat changes.  The GISS communication of a global average surface temperature trend, as a surrogate to describe global warming is quantitatively flawed (e.g. see and see for how the global average surface temperature trend is linked to  climate system heat changes [global warming]).

Paul Klemencic Question #2:

2. It appears that correcting the land reading by the large warm bias in this report would wipe out almost all of the land warming trend. If so, is a stable or cooling land surface trend consistent with satellite measurements over the continents showing warming of the lower and mid-level troposphere?

[Gavin Schmidt Response:This is not evidence that the land surface trend needs to be adjusted if you are comparing like with like. There is plenty of reasons to expect the land surface trend to be faster than the ocean trends - just as is observed. - gavin]

Roger A. Pielke Sr. Comment: Gavin shows that he does not understand the issue raised in the text from the Mahmood et al paper.  There is a significant bias in the use of 2m minimum temperatures as a diagnostic for deeper atmospheric temperature trends and anomalies.  I can only imagine that Gavin superficially read our papers, if he read them at all.  He does clearly inadequately understand boundary layer dynamics.

Paul Klemencic Question #3:

3. The paper seems to conclude that much of the warming bias is due to heat generated from man’s activities other than the GHG forcing. Is the heat released from mankind’s activities enough to explain the warming bias of 0.21 K per decade?

[Gavin Schmidt Response:Really? First off, this isn't evidence that there is a bias in the surface temperature trends. Secondly, I don't think this is related to the direct output of waste heat into the atmosphere. This might be locally important in some regions, but as a global effect (or even just a land effect) it is a couple of orders magnitude smaller than the impact of increased CO2 on the forcing. - gavin]

Roger A. Pielke Sr. Comment: Here Paul Klemencic misinterprets the papers.  While waste heat certainly is another effect that will alter the minimum temperatures, the issue we raise occurs whenever there are stably surface boundary layers. This typically occurs everywhere at night (particularly on clear and light wind nights) and in the high latitudes in the winter.  This happens even in pristine landscapes. Gavin Schmidt, by not reading the papers, or as a result of his lack of knowledge regarding boundary layer dynamics, did not accurately reply to Paul’s question.

Final Paul Klemencic Comment

If you would prefer to defer addressing this issue and answering these questions at this time, I will understand.

Roger A. Pielke Sr. Comment:  Gavin Schmidt should have invited me (or one of our other co-authors to respond). Clearly, however, despite clear evidence of his inadequate lack of knowledge of boundary layer physics, he elected to be the authority on our research papers.  This just further documents that Real Climate does not present balanced viewpoints on research papers, but uses misinformation to seek to discredit them. This is a pity, since Gavin Schmidt, if he would educate himself on the issues we raise, could contribute significantly to a constructive discussion of our papers. So far, he has not done so.

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Major Errors In James Annan’s Post “Pielke and Matsui (2005) revisited”

UPDATE: James made this new claim on his weblog titled PM05 resolved (see his comment linked to one of my weblogs in the last paragraph of his post).

Roger,

The change in heating rate in those plots is much less than 0.05K/day near the surface, probably 0.01K/day (green curve = relevant to the real world). How do you reconcile this with the change in heating rate of about 0.1K PER HOUR that you used in your calculations?

The classic book The Climate Near the Ground by Geiger et al (reprinted most recently in 2009) illustrates the error in James’s statement.  On page 124,  for example, they report changes of at least 0.1C  PER HOUR, and often more, as a result of changes in vertical stratification and surface characteristics. The sensitivity of the 2m  temperatures to the overlying thermodynamic stability, intensity of turbulent mixing, and surface fluxes is illustrated even in this early study.  The authors discuss atmospheric moisture and cloud cover effects elsewhere in their excellent book. I recommend that James read this text to update himself on the surface boundary layer and for an explanation of the physics of minimum temperatures that occur overnight.

*******************************************************************************

James Annan has posted on his weblog  “Pielke and Matsui (2005) revisited”. In it, he perpetuates his misunderstanding of that paper, as well as its role in defining the issue that is examined further in Lin et al 2007 and Klotzbach et al 2009.

His errors start with his text [where he is referring to

Pielke Sr., R.A., and T. Matsui, 2005: Should light wind and windy nights have the same temperature trends at individual levels even if the boundary layer averaged heat content change is the same?Geophys. Res. Letts., 32, No. 21, L21813, 10.1029/2005GL024407]

“In all this work, they apply the radiative cooling at the surface, even though they explicitly portray this forcing as being representative of the effect that arises from a change in GHG concentrations. Standard climate theory holds that the radiative forcing is applied the top of the atmosphere – indeed this is the level at which the forcing is defined. It is simply wrong to claim that a doubling of CO2 will generate a forcing of 3.7Wm-2 at the surface, for example.”

What we actually wrote is

“……if the nocturnal boundary layer heat fluxes change over time, the trends of temperature under light winds in the surface layer will be a function of height, and that the same trends of temperature will not occur in the surface layer on windy and light wind nights.”

The addition of CO2 was presented as just one example of how the nocturnal boundary layer fluxes can change over time.  Other examples, include changes in atmospheric water vapor content, cloudiness , and alterations in the surface heat fluxes due to landscape change.

He clearly further illustrates his misunderstanding of this issue as he wrote

“Thus, a large increase in GHGs generates a warming rate of about 0.04K per day across the boundary layer, as compared to the Pielkian ~1K over a single night (depending on wind speed).”

We never stated that there would be a 1K change across the boundary layer. He has completely  misrepresented our paper. 

 The 1K change is concentrated near the surface (e.g. 2m).  Figure 1 in

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

provides a real world example of how the nocturnal boundary layer cools during the night.

With respect to the actual changes in surface heat fluxes due to a doubling of CO2, this  is discussed on my weblog at

Relative Roles of CO2 and Water Vapor in Radiative Forcing).

Further Analysis Of Radiative Forcing By Norm Woods

where the instantaneous simulated flux change from a doubling of CO2 is on the order of 1 Watt per meter squared, as we used in Pielke and Matsui paper. However, it does not matter in our analysis,, what the reason for a change in the cooling rate of 1 Watt per meter squared is.

He also writes

“The startling impact of this odd application of “bottom of the atmosphere” forcing is apparent from their Table 1. A change in this “forcing” of a mere 1Wm-2 leads to a temperature difference of a whopping 1.5C (at the 2m level) over a single calm night! This is the simple result of applying 1Wm-2 of cooling to the fairly shallow layer at the bottom of the atmosphere, which has relatively low heat capacity due to its shallowness.”

He actually recognizes the issue (the cooling effect is concentrated in a fairly shallow layer), but does not see its significance!

The 1.5C temperature difference that he lists results from the manner in which  cooling is vertically distributed in the surface boundary layer.  With stronger winds, for example, this heating is distributed through a deeper layer.

What we have explored in the Pielke and Matsui (2005), Lin et al (2007) and Klotzbach et al (2009) papers is summarized as follows:

1.  A global average surface temperature trend is used to diagnose the magnitude of global warming.  This is clearly shown in the equation (from NRC, 2005)

dH/dt = f – T’/λ  

where H is the heat content in Joules of the climate system, f is the radiative forcing at the top of the tropopause, T’ is the change in surface temperature in response to a change in heat content, and λ is the climate feedback parameter. Equation (1) above is a thermodynamic proxy for the thermodynamic state of the Earth system; as such, it must be tightly coupled to that
thermodynamic state, as we wrote in our 2007 JGR paper

2. T’ is computed from the equation

T’ = [T' (over the ocean) *  area of the ocean + T' (over land) * area of the land]/[area of the Earth's surface].

3. T’(over land) = [T' (maximum) + T' (minimum)]/2

4.  T’ is supposed to be monitored at a standard height (e.g. 2m); if it is not, this introduces another bias, but for this discussion, I will assume that all of the land measurements are at 2m.

5. Our papers show that whenever the boundary layer is stably stratified, any alteration in the cooling rate (for any reason), results in a greater temperature change in T’ at 2m than would occur higher up.

6. This means that these values of T’ (from the 2m height) are NOT an appropriate thermodynamic proxy for the thermodynamic state of the Earth system. Values of of temperature anomalies used to calculate  T’ when the atmosphere is stably stratified are not tightly coupled to the thermodynamic state of the global climate system. 

6. Using observed data from Lin et al 2007,  we report (see) that

“[T]he monitoring (and predicting with multi-decadal global models) the temperature at a single level over land near the surface, as representative of deeper layer temperature trends that are positive, introduces a significant warm biasUntil further analysis is completed using temperature trend data at two or more levels near the surface, the best estimate that we have is that this warm bias  explains about 30%of the IPCC estimate of global warming [based on a global average surface temperature trend].”

As a final comment, I have worked with James Annan in the past (see). I would be disappointed if he now has decided join the group (such as we see on Real Climate) who inaccurately discuss research papers  in order to discredit them.

 

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Guest Weblog By Kiminori Itoh “Soot And The Arctic Ice – A Win-Win Policy Based On Chinese Coal Fired Power Plants”

Kiminori Itoh of Yokohama National University has prepared a guest weblog for us. It is titled “Soot And The Arctic Ice – A Win-Win Policy Based On Chinese Coal Fired Power Plants” [UPDATE: see also Mike Smith's Guest Weblog on this subject]

GUEST WEBLOG

As you saw in a recent weblog in Climate Science, China appears to be modifying the global climate through aerosol emission from a large number of coal fired power plants: August 12, 2009, New Paper “Increase In Background Stratospheric Aerosol Observed With Lidar” By Hofmann Et Al 2009.  This paper gave me an idea that soot from China may be responsible for the recent reduction of the Arctic ice, which finally leads me to a Win-Win policy on coal fired power plants in China, as you see below.

The target of the paper of Hofmann et al was  sulfate aerosol transported into stratosphere. Thus, its main effect on the global climate is cooling of the troposphere and warming of  the stratosphere similar to volcanic eruptions. In fact, this paper was introduced in Science (24 July 2009, p. 373) with the title of “China’s Human Volcano.”

The Chinese aerosol, however, can have another effect on the climate. That is, a possible influence of soot on the Arctic ice. It seems to me that Hofmann et al.’s paper, together with other recent findings, gives evidence for this possibility as follows:

1) Hofmann et al’s paper shows that stratospheric haze became densest in 2007 and declined a little after that. According to their claim, this is associated with the changes in sulfate emissions from China. This fact reminds me that the ice extent in the Arctic sea was significantly reduced in the 2007 summer and recovered after that. Since the amount soot should be proportional to that of sulfate, also the amount soot transported to the Arctic may have a peak in 2007, and may explain the dramatic reduction of the sea ice extent; the soot deposited onto the ice surfaces absorbs sun light of Arctic summer, gives heat to the ice, and lets it melt. This process should be particularly effective during summer of the Arctic when the sun does not set.

2) About half of the recent temperature increase in the Arctic region is reportedly due to aerosols (combination effects of sulfate and soot) (D. Shindell and G. Faluvegi, Nature Geosci. 2, 294-300 (2009)); this result convinces one that the influence of soot on the Arctic environment does exist.

3) There are other recent papers on soot: e. g., “Atmospheric brown clouds: Hemispherical and regional variations in long-range transport, absorption, and radiative forcing,” V. Ramanathan et al., J. Geophys. Res. vol. 112, D22S21, doi:10.1029/2006JD008124, 2007.

From these results, I suspect that the soot from China is responsible for the recent reduction of sea ice in the Arctic summer. To verify this, detailed chemical analyses, such as carbon allotropes, should be made if the soot can be sampled from the ice (this may be an interesting project).

Thus, I can claim that the influence of the soot is likely large. Then, according to the spirit of the precautionary principle, the soot from China should be reduced even if  the scientific basis is not sufficient. The precautionary principle should be applied not just to CO2, but to other primary factors of climate changes. If this is not possible just because there is no statement on soot in the FCCC (Framework of Convention of Climate Change), we need another convention (or protocol) which enables us to treat soot properly. Otherwise, countermeasures on climate change will be useless.

Now, I want to point out that the reduction of the Chinese soot can become a Win-Win policy for China as well as for other countries. About 80% of the Chinese electricity comes from coal fired power plants. The CO2 emission from China in 2004 was about 2.27 billion metric tons, which was 8.6% of the world emissions (26.3 billion metric tons). But, their efficiency of energy production is still low (34.6% as an average), and emissions other than CO2 and aerosol (i. e., mainly SOx, NOx and mercury) bring heavy health problems as well. In fact, resultant atmospheric pollution causes 300 thousands to 400 thousands of deaths a year.

If countries like Japan, which has advanced technologies of coal fired power plants (e. g., energy production efficiency being 41.1% in Japan), can cooperate with China to increase the efficiency of energy production and to decrease all kinds of emissions, this will become a true Win-Win policy. China can save a lot of human lives and working hours, can reduce the influence of the aerosol on the global climate, and in addition, can reduce CO2 emission. The other countries also benefit from this policy, including economical ones and a reduction of transboundary pollution.

This Win-Win policy actually will reduce the emission of CO2. Just from this aspect, it is much better than the cap-and-trade policy which in fact will increase the CO2 emissions. Moreover, and importantly, when considering a large capacity of coal reserves, this is a reasonable tactics in near future.

With this kind of Win-Win policies, developing countries like China can agree with developed countries on their energy policies. There will be no progress in the negotiation between them if the developing countries can participate in the climate policies only through the reduction of CO2. We need flexible approaches for complicated issues like the climate changes.

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Comment on The Webog Of Michael Tobis “My Final Word on Klotzbach”

Michael Tobis at Only In It For The Gold has posted a weblog titled “My Final Word on Klotzbach”.  In it he perpetuates the misinformation concerning our paper that I reported on earlier today (see).  He continues, for example,  to assume we are talking about an error in the measurement of the surface temperatures (which we are not), and to claim that the Eastman et al 2001 paper misrepresents the radiative effect of added CO2 over the time scale of our model simulation.

In the Eastman et al paper, we showed that for short (monthly) time scales, the biogeochemical effect of added CO2 and of land use change were larger effects on the seasonal weather than the radiative effect of CO2.  The advection of weather from outside the regional domain was the same for each of our model sensitivity experiments.  This does not mean the radiative effect is not important at longer time periods (it is), but its biogeochemical effect is much more immediate.

The Eastman et al paper citation was just presented to illustrate one of the effects (added CO2 and H2O) which can reduce the long wave cooling to space.  The conclusions of our paper are not at all affected by that paper.

Our paper is dependent on the paper

Lin, X., R.A. Pielke Sr., K.G. Hubbard, K.C. Crawford, M. A. Shafer, and T. Matsui, 2007: An examination of 1997-2007 surface layer temperature trends at two heights in Oklahoma. Geophys. Res. Letts., 34, L24705, doi:10.1029/2007GL031652.

This is the one Micheal Tobis should be commenting on, if he disagrees with our findings.  Also, we published the issue of a warm bias (and other uncertainties and biases in the surface temperature trend record) in

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.

Except for one Comment in JGR (see),  and our Reply (see and see), our paper remains without any peer reviewed disagreement of our findings. Michael Tobis should read and comment on this paper, also, if he wants to be convincing that he is actually understanding the science.

I will repeat here what we have reported in our paper, and on the blogs;

“[T]he temperature at a single level over land near the surface, as representative of deeper layer temperature trends that are positive, introduces a significant warm bias.”

Moreover, despite his claim that much of the trend is in the tropics, as seen in the figure from NCDC reproduced in my weblog New Paper Documents A Warm Bias In The Calculation Of A Multi-Decadal Global Average Surface Temperature Trend – Klotzbach Et Al (2009), there is a substantial warm anomaly at higher latitudes over land.

With respect to his statements that

“1) The mechanism described in Pielke & Matsui is surely real in this respect: as greenhouse gases increase and global warming proceeds, the strength of extreme nighttime near-surface inversions will decline. If it is faster than other effects it will contribute to making the surface temperature trend go up without affecting the middle atmosphere trends.

This comment is certainly true, and fits with our findings. If Micheal really accepts this, then he should agree that using the surface temperature trend as a diagnostic of global warming (e.g. see pages 19-21 in NRC, 2007) is an inadequate metric.

2) It is implausible that this effect is large enough in the aggregate (common enough as a fraction of space and time) to account for discrepancies in global trends in GCMs. It would take quite a lot of serious revisiting of boundary layer theory and boundary layer implementation in models to quantify the expected effect to demonstrate this one way or the other, work that the Pielke crowd has not undertaken.”

Our conclusion is based on the Lin et al (2007) paper and substantiated by the Klotzbach et al 2009 (2009) paper.  Stating that “It is implausible that this effect is large enough in the aggregate (common enough as a fraction of space and time) to account for discrepancies in global trends in GCMs” documents that he has failed to complete the actual  quantitative analysis to refute our claims. The warm bias we have identified occurs whenever the overlying atmosphere warms and the surface boundary layer is stably stratified.

The bottom line conclusion that should be reached is that Michael Tobis has not completed a proper scientific assessment of our paper, but rather, has other motives for dismissing it.  This is unfortunate, since if he would actually engage in a constructive debate on this subject with questions and answers, everyone would benefit. He is certainly welcome to do this on my weblog or on his.

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The Global Average Surface Temperature Warming Really Is Overstated

There have been a remarkable amount of (deliberate?) misunderstanding regarding our new paper

Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr., J.R. Christy, and R.T. McNider, 2009: An alternative explanation for differential temperature trends at the surface and in the lower troposphere. J. Geophys. Res., in press.

Examples of  misunderstanding in the blogosphere (as reported on Roger Pielke Jr.’s Blog)   include:

http://julesandjames.blogspot.com/2009/08/curiouser-and-curiouser.html

http://initforthegold.blogspot.com/2009/08/pielkes-all-way-down.html

For those who are open-minded on this issue, I have summarized the findings below.

The Klotzbach et al paper examined if other real world data are consistent with the conclusion from our earlier papers;

“[F]rom our papers (Pielke and Matsui 2005 and Lin et al. 2007), a conservative estimate of the warm bias resulting from measuring the temperature near the ground is around 0.21 C per decade (with the nightime T(min) contributing a large part of this bias) . Since land covers about 29% of the Earth’s surface (see), the warm bias due to this influence explains about 30% of the IPCC estimate of global warming. In other words, consideration of the bias in temperature would reduce the IPCC trend to about 0.14 degrees C per decade, still a warming, but not as large as indicated by the IPCC”

This finding is based on observed temperature trends at two levels. While it is certainly a limited set of data, the theoretical basis for this conclusion, based on boundary layer physics is solid (see als0) .

The Klotozbach et al paper used data from both the surface and tropospheric analyses to further explore this issue. If the finding we made in Lin et al 2007 is robust than the following two hypotheses should be false;

1) If there is no warm bias in the surface temperature trends, then there should not be an increasing divergence with time between the lower troposphere and surface temperature anomalies. The difference between lower troposphere and surface temperature anomalies should not be greater over land areas.
 
2) If there is no warm bias in the surface temperature trends then the divergence should not be larger for both maximum and minimum temperatures at high latitude land locations in the winter.

Both were falsified. This provides significant further support to our conclusion that the monitoring (and predicting with multi-decadal global models) the temperature at a single level over land near the surface, as representative of deeper layer temperature trends that are positive, introduces a significant warm bias. Until further analysis is completed using temperature trend data at two or more levels near the surface, the best estimate that we have is that this warm bias  explains about 30% of the IPCC estimate of global warming [based on a global average surface temperature trend].

 

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New Paper “Impacts Of Land Use Land Cover Change On Climate And Future Research Priorities” By Mahmood Et Al 2009

We have a new multi-authored paper that has been accepted.  This paper illustrates the breadth and diversity of scientists who have concluded that land use/land cover change is a first order climate forcing.

The paper is

Mahmood, R., R.A. Pielke Sr., K.G. Hubbard, D. Niyogi, G. Bonan, P. Lawrence, B. Baker, R. McNider, C. McAlpine, A. Etter, S. Gameda, B. Qian, A. Carleton, A. Beltran-Przekurat, T. Chase, A.I. Quintanar, J.O. Adegoke, S. Vezhapparambu, G. Conner, S. Asefi, E. Sertel, D.R. Legates, Y. Wu, R. Hale, O.W. Frauenfeld, A. Watts, M. Shepherd, C. Mitra, V.G. Anantharaj, S. Fall,R. Lund, A. Nordfelt, P. Blanken, J. Du, H.-I. Chang, R. Leeper, U.S. Nair, S. Dobler, R. Deo, and J. Syktus, 2009: Impacts of land use land cover change on climate and future research priorities. Bull. Amer. Meteor. Soc., accepted.

The paper starts with the text

“Human activities have modified the environment for thousands of years. Significant population increase, migration, and accelerated socio-economic activities have intensified these environmental changes over the last several centuries. The climate impacts of these changes have been found in local, regional, and global trends in modern atmospheric temperature records and other relevant climatic indicators.”

In our conclusions, we write

“It is the regional responses, not a global average, that produce drought, floods and other societally important climate impacts.”

as well as make the following recommendations

“we recommend, as a start, to assess three new climate metrics:

1. The magnitude of the spatial redistribution of land surface latent and sensible heating (e.g., see Chase et al. 2000; Pielke et al. 2002). The change in these fluxes into the atmosphere will result in the alteration of a wide variety of climate variables including the locations of major weather features. For example, Takata et al. (2009) demonstrated the major effect of land use change during the period 1700-1850 on the Asian monsoon. As land cover change accelerated after 1850 and continues into the future, LULCC promises to continue to alter the surface pattern of sensible and latent heat input to the atmosphere.

2. The magnitude of the spatial redistribution of precipitation and moisture convergence (e.g., Pielke and Chase 2003). In response to LULCC, the boundaries of regions of wet and dry climates can change, thereby affecting the likelihood for floods and drought. This redistribution can occur not only from the alterations in the patterns of surface sensible and latent heat, but also due to changes in surface albedo and aerodynamic roughness (e.g., see Pitman et al. 2004; Nair et al. 2007).

3. The normalized gradient of regional radiative heating changes. Since it is the horizontal gradient of layer-averaged temperatures that force wind circulations, the alteration in these temperatures from any human climate forcing will necessarily alter these circulations. In the evaluation of the human climate effect from aerosols, for example, Matsui and Pielke (2006) found that, in terms of the gradient of atmospheric radiative heating, the role of human inputs was 60 times greater than the role of the human increase in the well-mixed greenhouse gases. Thus, this aerosol effect has a much more significant role on the climate than is inferred when using global average metrics. We anticipate a similar large effect from LULCC. Feddema et al. (2005), for example, have shown that global averages mask the impacts on regional temperature and precipitation changes. The above climate metrics can be monitored using observed data within model calculations such as completed by Matsui and Pielke (2006) for aerosols, as well as by using reanalyses products, such as performed by Chase et al (2000) with respect to the spatial pattern of lower tropospheric heating and cooling. They should also be calculated as part of future IPCC and other climate assessment multi-decadal climate model simulations.”

We also write

“With respect to surface air temperatures, for example, there needs to be an improved quantification of the biases and uncertainties in multi-decadal temperature trends, which remain inadequately evaluated in assessment reports such as from the Climate Change Science Program (CCSP 2006). We also recommend that independent committees (perhaps sponsored by the National Science Foundation) conduct these assessments.”

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New Thesis “The Influence Of Landfall Variation On Tropical Cyclone Losses In The United States As Simulated By HAZUS” By K. Sharp 2009

There is an excellent new M.S. Thesis which I would like to alert you to. The topic fits within the vulnerability framework which, as reported frequently on my weblog, is an effective way to deal with risk from climate and other environmental variability and change. The Thesis is

Sharp, Kevin, 2009, M.S. Thesis: The influence of landfall variation on tropical cyclone losses in the United States as simulated by HAZUS. Department of Geography, University of Colorado, 67 pp.

The abstract reads

Sharp, Kevin Joseph (M.A., Geography)

The Influence of Landfall Variation on Tropical Cyclone Losses in the United States as Simulated by HAZUS

Thesis directed by Dr. William R. Travis

“Tropical cyclone losses in the United States have shown an increasing trend since the beginning of the 20th century. This is mainly due to increased exposure along America’s coast. The amount of coastal property at risk persistently increases due to inflation, wealth increase, and population growth. When researchers have normalized the loss record to remove the influence of exposure and vulnerability change, no trend can be discerned in the damage record. This has been used to refute the claim that tropical cyclones are becoming more potentially destructive, and to keep the locus of explanation firmly in socio-demographic trends. But physical variation, in storm size, intensity and location, still make a significant difference the impact of any individual storm event. This fact occasionally induces calls renewed efforts at hurricane modification and routinely evokes a sense of either or alarm at “close calls” that, except for a difference of a few miles in landfall location or a modest weakening of peak winds, separate hurricane disasters from catastrophes. This project examined the effect of landfall location on storm damage using the Federal Emergency Management Agency’s (FEMA) risk assessment HAZUS. Thirty-mile track shifts were prescribed for the top 10 most damaging storms in the normalized record since 1988. The alternate storms yielded drastically different damage estimates from the original storms, indicating large spatial variations in exposure. Each landfall shift resulted in a rank change in the overall normalized record. The damage record is dominated by individual extreme events like those used in this analysis, and although random, differences in landfall location would presumably average out in a long record. The fact that a few storms account for a large majority of losses, and that small differences in their landfall yield large differences in impact, points to a very large noise to signal ratio that would make it difficult to discern a climate-induced trend, and may also obscure some dimensions of socio-economic exposure and vulnerability trends.”

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Guest Weblog “Solar Variability And Its Effect On Climate Change” By Nicola Scafetta

In response to the interest in Nicola Scafetti’s earlier guest weblog (see), he has prepared another post for today.

Guest Weblog By Nicola Scafetti “Solar Variability And Its Effect On Climate Change”

Understanding solar variability and its effects on climate change has become  increasingly complex. While current climate models such as the EBMs and GCMs used by the IPCC claim that solar change can affect climate only slightly, empirical studies of climate data do suggest that solar changes have significantly altered climate both in the past and in more recent times, and will continue to affect climate in the future. Thus, from an empirical perspective modern climate models are poorly modeling the solar effect on climate change.

Herein I would like to advertise a conference session at the: AGU Fall Meeting, 14-18 December 2008, Monday-Friday, San Francisco, CA, USA that Dr. Willson and I are organizing.  For those who might be interested in submitting an abstract:  the abstract deadline for electronic submissions is the 3rd of September, 23:59 ET.

 AGU Fall Meeting, 14-18 December 2008
GC07: Solar Variability and its Effect on Climate Change
Conveners: Nicola Scafetta and Richard C. Willson
http://www.agu.org/meetings/fm09/program/scientific_session_search.php?show=detail&sessid=420

Description:

Solar variability and its climate change significance are to be explored. We invite papers relevant to solar variability and its effect on climate on all time scales including theoretical and empirical papers dealing with: 1) total solar irradiance observations and proxy reconstructions, solar magnetic activity, solar cosmic ray modulation and solar activity forecasts; 2) solar variation effects on global and local temperature cycles and trends, cloud cover, precipitations, droughts, floods, monsoons and stream
flow.

I also would like to advertise a new paper of mine that attempts to detect and reconstruct the solar signature on climate which is currently in press on the Journal of Atmospheric and Solar-Terrestrial Physics. This new paper also discusses some limitation of previous approaches. The paper is

Empirical analysis of the solar contribution to global mean air surface temperature change.
Journal of Atmospheric and Solar-Terrestrial Physics (2009), doi:10.1016/j.jastp.2009.07.007
By Nicola Scafetta

with the abstract

“The solar contribution to global mean air surface temperature change is analyzed by using an empirical bi-scale climate model characterized by both fast and slow characteristic time responses to solar forcing: t1 = 0.4 +/- 0.1 yr, and t2 = 8 +/- 2 yr or t2 = 12 +/- 3 yr. Since 1980 the solar contribution to climate change is uncertain because of the severe uncertainty of the total solar irradiance satellite composites. The sun may have caused from a slight cooling, if PMOD TSI composite is used, to a significant warming (up to 65% of the total observed warming) if ACRIM, or other TSI composites are used. The model is calibrated only on the empirical 11-year solar cycle signature on the instrumental global surface temperature since 1980. The model reconstructs the major temperature patterns covering 400 years of solar induced temperature changes, as shown in recent paleoclimate global temperature records.”

 

 

 

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My Climate Science Weblog Will Be Offline Wednesday August 19 2009

Climate Science will be offline Wednesday August 19 2009 in order to convert over to a new version of Word Press.  This important upgrade is courtesy of Anthony Watts [of Watts up With That]. Anthony is contributing to an improved understanding of climate science in many ways, and this is just one of his thoughtful contributions!  Thanks Anthony!

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New Paper “Ocean Heat Content and Earth’s Radiation Imbalance” By D.H. Douglas and R.S. Knox 2009

There is a very important new paper that uses heat content of the climate system in Joules in order to diagnose global warming and cooling (see also).

It is

Douglass, D.H. and R. Knox, 2009: Ocean heat content and Earth’s radiation imbalance. Physics letters A

The abstract reads

“Earth’s radiation imbalance is determined from ocean heat content data and compared with results of direct measurements. Distinct time intervals of alternating positive and negative values are found: 1960– mid 1970s (−0.15), mid-1970s–2000 (+0.15), 2001–present (−0.2 W/m2), and are consistent with prior reports. These climate shifts limit climate predictability.”

The summary reads

“We determine Earth’s radiation imbalance by analyzing three recent independent observational ocean heat content determinations for the period 1950 to 2008 and compare the results with direct measurements by satellites. A large annual term is found in both the implied radiation imbalance and the direct measurements. Its magnitude and phase confirm earlier observations that delivery of the energy to the ocean is rapid, thus eliminating the possibility of long time constants associated with the bulk of the heat transferred.

Longer-term averages of the observed imbalance are not only many-fold smaller than theoretically derived values, but also oscillate in sign. These facts are not found among the theoretical predictions.

Three distinct time intervals of alternating positive and negative imbalance are found: 1960 to the mid 1970s, the mid 1970s to 2000 and 2001 to present. The respective mean values of radiation imbalance are −0.15, +0.15, and −0.2 to −0.3. These observations are consistent with the occurrence of climate shifts at 1960, the mid-1970s, and early 2001 identified by Swanson and Tsonis.

 Knowledge of the complex atmospheric-ocean physical processes is not involved or required in making these findings. Global surface temperatures as a function of time are also not required to be known.”

This excellent paper shows why we need to focus on climate system heat content changes as urged in

Ellis et al. 1978: The annual variation in the global heat balance of the Earth. J. Climate. 83, 1958-1962

Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335

Pielke Sr., R.A., 2008: A broader view of the role of humans in the climate system. Physics Today, 61, Vol. 11, 54-55

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