Tuesday, September 10, 2013

New paper finds IPCC climate models don't realistically simulate convection

More problems for the models: A paper published today in Geophysical Research Letters finds climate models do not realistically simulate convection, "a key element of the weather and climate system for transporting mass, momentum, and thermal energy," because of a large gap in the scale or resolution required to simulate convection [1-2 km] compared to global atmospheric motions [on the order of 10,000 km]. 

According to the authors, "It has been challenging to simulate convection realistically in global atmospheric models, because of the large gap in spatial scales between convection (10^0 km) and global motions (10^4 km)." The authors find "an essential change for convection statistics occurred around 2-km grid spacing. The convection structure, number of convective cells, and distance to the nearest convective cell dramatically changed at this [2 km] resolution," which is a much, much smaller resolution than used by IPCC climate models [50-100km grid size in AR5 models]. 

Skeptics such as Dr. Noor van Andel have shown that the so-called "human fingerprint" or "hot spot" of global warming [that exists only in climate models] is a consequence of incorrect assumptions regarding convection, and this new paper may shed light on the reasons why.

Deep moist atmospheric convection in a sub-kilometer global simulation

Yoshiaki Miyamoto, Yoshiyuki Kajikawa, Ryuji Yoshida, Tsuyoshi Yamaura, Hisashi Yashiro, Hirofumi Tomita

Deep moist atmospheric convection is a key element of the weather and climate system for transporting mass, momentum, and thermal energy. It has been challenging to simulate convection realistically in global atmospheric models, because of the large gap in spatial scales between convection (10^0 km) and global motions (10^4 km). We conducted the first ever sub-kilometer global simulation and described the features of convection. Through a series of grid-refinement resolution testing, we found that an essential change for convection statistics occurred around 2-km grid spacing. The convection structure, number of convective cells, and distance to the nearest convective cell dramatically changed at this resolution. The convection core was resolved using multiple grids in simulations with grid spacings less than 2.0 km.

8 comments:

  1. Proposed high resolution model only has resolution of 10 X 10 km or 100 sq km, i.e. grid cells far too large to realistically simulate convection

    http://www.sciencemag.org/content/341/6151/1160.summary?rss=1

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  2. Now let’s see what CAGW has chosen to ignore from Arrhenius:
    http://en.wikipedia.org/wiki/Svante_Arrhenius


    ΔF = α Ln(C/C_0)

    “In his calculation Arrhenius included the feedback from changes in water vapor as well as latitudinal effects, but he omitted clouds, convection of heat upward in the atmosphere, and other essential factors.”

    ReplyDelete
  3. Rud Istvan says:
    September 13, 2013 at 4:46 pm
    Throwing good money after bad is never wise.
    All GCMs fail because the grid scale resolution you post (same image used in my book) is far too coarse to resolve things like tropical thunderstorm convection cells (which is why GCMs cannot resolve Lindzens adaptive iris, and therefore why CMIP5 still gets the water vapor feedback wrong, therefore why they still predict an equatorial troposphere hot spot when there isn’t one), or clouds.
    This is inherent in the most powerful supercomputers, which are a couple of orders of magnitude not powerful enough to be able to adequately model these necessary phenomena on suitable small gridscales. Leaked AR5 WG1 SOD Chapter 7 (clouds) even said they may never be powerful enought to do so, before concluding that cloud feedback was significantly positive based on (and this is a direct quote) “unknown contributions by processes yet to be accounted for.”
    IPCC cargo cult science.
    So this formal appeal for GCM consolidation has very little real appeal. First rule of holes if you are in one and want out: stop digging.

    ReplyDelete
  4. Rud Istvan says:
    September 13, 2013 at 4:46 pm
    Throwing good money after bad is never wise.
    All GCMs fail because the grid scale resolution you post (same image used in my book) is far too coarse to resolve things like tropical thunderstorm convection cells (which is why GCMs cannot resolve Lindzens adaptive iris, and therefore why CMIP5 still gets the water vapor feedback wrong, therefore why they still predict an equatorial troposphere hot spot when there isn’t one), or clouds.
    This is inherent in the most powerful supercomputers, which are a couple of orders of magnitude not powerful enough to be able to adequately model these necessary phenomena on suitable small gridscales. Leaked AR5 WG1 SOD Chapter 7 (clouds) even said they may never be powerful enought to do so, before concluding that cloud feedback was significantly positive based on (and this is a direct quote) “unknown contributions by processes yet to be accounted for.”
    IPCC cargo cult science.
    So this formal appeal for GCM consolidation has very little real appeal. First rule of holes if you are in one and want out: stop digging.

    ReplyDelete
  5. http://www.klimatupplysningen.se/2011/08/22/signatur-igen/#.Ujgtn9LkuE-

    ReplyDelete
  6. The grid size of 100 km x 100 km used in climate models is also far too large to realistically model clouds as well as convection

    http://www.eenews.net/stories/1059988117

    ReplyDelete
  7. IPCC climate models use a resolution of 200 km

    Even the highest currently possible resolution with regional models can only get to 12 km, far short of the 1-2 km required to realistically simulate convection

    http://www.sciencedaily.com/releases/2013/12/131204091144.htm

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  8. "most models don't simulate convection well", or the effects of clouds on convection:

    http://environmentalresearchweb.org/cws/article/yournews/55508

    ReplyDelete

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