[Response: Well, something like
a circulation changed forced by the NAO pattern (which may in turn be affected by greenhouse gases) might cause an increase in European air temperatures, which in turn would allow low level moisture to increase if there is enough moisture supply, which would then constitute an amplification of a signal driven remotely.
Not exact matches
Countless additional
forces — melting ice sheets, shifts in precipitation,
changes in atmospheric and oceanic
circulation, to name a few — will influence the process as well.
In the study, researchers analyzed a series of transient Coupled General
Circulation Model simulations
forced by
changes in greenhouse gases, orbital
forcing, meltwater discharge and the ice - sheet history throughout the past 21,000 years.
Indeed, one of the findings in the recent paper by Overpeck et al. (this weeks Science), is that even as the Greenland ice sheet melts faster than originally expected, it still won't provide sufficient meltwater
forcing of the North Atlantic
circulation (which is the feature of the climate system most commonly implicated in the discussion of «tipping points») to
force any sort of threshold
change.
g (acceleration due to gravity) G (gravitational constant) G star G1.9 +0.3 gabbro Gabor, Dennis (1900 — 1979) Gabriel's Horn Gacrux (Gamma Crucis) gadolinium Gagarin, Yuri Alexeyevich (1934 — 1968) Gagarin Cosmonaut Training Center GAIA Gaia Hypothesis galactic anticenter galactic bulge galactic center Galactic Club galactic coordinates galactic disk galactic empire galactic equator galactic habitable zone galactic halo galactic magnetic field galactic noise galactic plane galactic rotation galactose Galatea GALAXIES galaxy galaxy cannibalism galaxy classification galaxy formation galaxy interaction galaxy merger Galaxy, The Galaxy satellite series Gale Crater Galen (c. AD 129 — c. 216) galena GALEX (Galaxy Evolution Explorer) Galilean satellites Galilean telescope Galileo (Galilei, Galileo)(1564 — 1642) Galileo (spacecraft) Galileo Europa Mission (GEM) Galileo satellite navigation system gall gall bladder Galle, Johann Gottfried (1812 — 1910) gallic acid gallium gallon gallstone Galois, Évariste (1811 — 1832) Galois theory Galton, Francis (1822 — 1911) Galvani, Luigi (1737 — 1798) galvanizing galvanometer game game theory GAMES AND PUZZLES gamete gametophyte Gamma (Soviet orbiting telescope) Gamma Cassiopeiae Gamma Cassiopeiae star gamma function gamma globulin gamma rays Gamma Velorum gamma - ray burst gamma - ray satellites Gamow, George (1904 — 1968) ganglion gangrene Ganswindt, Hermann (1856 — 1934) Ganymede «garbage theory», of the origin of life Gardner, Martin (1914 — 2010) Garneau, Marc (1949 ---RRB- garnet Garnet Star (Mu Cephei) Garnet Star Nebula (IC 1396) garnierite Garriott, Owen K. (1930 ---RRB- Garuda gas gas chromatography gas constant gas giant gas laws gas - bounded nebula gaseous nebula gaseous propellant gaseous - propellant rocket engine gasoline Gaspra (minor planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson gauge theory gauss (unit) Gauss, Carl Friedrich (1777 — 1855) Gaussian distribution Gay - Lussac, Joseph Louis (1778 — 1850) GCOM (Global
Change Observing Mission) Geber (c. 720 — 815) gegenschein Geiger, Hans Wilhelm (1882 — 1945) Geiger - Müller counter Giessler tube gel gelatin Gelfond's theorem Gell - Mann, Murray (1929 ---RRB- GEM «gemination,» of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone gene gene expression gene mapping gene pool gene therapy gene transfer General Catalogue of Variable Stars (GCVS) general precession general theory of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time geology GEOLOGY AND PLANETARY SCIENCE geomagnetic field geomagnetic storm geometric mean geometric sequence geometry GEOMETRY geometry puzzles geophysics GEOS (Geodetic Earth Orbiting Satellite) Geosat geostationary orbit geosynchronous orbit geosynchronous / geostationary transfer orbit (GTO) geosyncline Geotail (satellite) geotropism germ germ cells Germain, Sophie (1776 — 1831) German Rocket Society germanium germination Gesner, Konrad von (1516 — 1565) gestation Get Off the Earth puzzle Gettier problem geyser g -
force GFO (Geosat Follow - On) GFZ - 1 (GeoForschungsZentrum) ghost crater Ghost Head Nebula (NGC 2080) ghost image Ghost of Jupiter (NGC 3242) Giacconi, Riccardo (1931 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch Giant Magellan Telescope giant molecular cloud giant planet giant star Giant's Causeway Giauque, William Francis (1895 — 1982) gibberellins Gibbs, Josiah Willard (1839 — 1903) Gibbs free energy Gibson, Edward G. (1936 ---RRB- Gilbert, William (1544 — 1603) gilbert (unit) Gilbreath's conjecture gilding gill gill (unit) Gilruth, Robert R. (1913 — 2000) gilsonite gimbal Ginga ginkgo Giotto (ESA Halley probe) GIRD (Gruppa Isutcheniya Reaktivnovo Dvisheniya) girder glacial drift glacial groove glacier gland Glaser, Donald Arthur (1926 — 2013) Glashow, Sheldon (1932 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch Global Astrometric Interferometer for Astrophysics (GAIA) Global Oscillation Network Group (GONG) Globalstar globe Globigerina globular cluster globular proteins globule globulin globus pallidus GLOMR (Global Low Orbiting Message Relay) GLONASS (Global Navigation Satellite System) glossopharyngeal nerve Gloster E. 28/39 glottis glow - worm glucagon glucocorticoid glucose glucoside gluon Glushko, Valentin Petrovitch (1908 — 1989) glutamic acid glutamine gluten gluteus maximus glycerol glycine glycogen glycol glycolysis glycoprotein glycosidic bond glycosuria glyoxysome GMS (Geosynchronous Meteorological Satellite) GMT (Greenwich Mean Time) Gnathostomata gneiss Go Go, No - go goblet cell GOCE (Gravity field and steady - state Ocean
Circulation Explorer) God Goddard, Robert Hutchings (1882 — 1945) Goddard Institute for Space Studies Goddard Space Flight Center Gödel, Kurt (1906 — 1978) Gödel universe Godwin, Francis (1562 — 1633) GOES (Geostationary Operational Environmental Satellite) goethite goiter gold Gold, Thomas (1920 — 2004) Goldbach conjecture golden ratio (phi) Goldin, Daniel Saul (1940 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon GOMS (Geostationary Operational Meteorological Satellite) gonad gonadotrophin - releasing hormone gonadotrophins Gondwanaland Gonets goniatite goniometer gonorrhea Goodricke, John (1764 — 1786) googol Gordian Knot Gordon, Richard Francis, Jr. (1929 — 2017) Gore, John Ellard (1845 — 1910) gorge gorilla Gorizont Gott loop Goudsmit, Samuel Abraham (1902 — 1978) Gould, Benjamin Apthorp (1824 — 1896) Gould, Stephen Jay (1941 — 2002) Gould Belt gout governor GPS (Global Positioning System) Graaf, Regnier de (1641 — 1673) Graafian follicle GRAB graben GRACE (Gravity Recovery and Climate Experiment) graceful graph gradient Graham, Ronald (1935 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) Granat Grand Tour grand unified theory (GUT) Grandfather Paradox Granit, Ragnar Arthur (1900 — 1991) granite granulation granule granulocyte graph graph theory graphene graphite GRAPHS AND GRAPH THEORY graptolite grass grassland gravel graveyard orbit gravimeter gravimetric analysis Gravitational Biology Facility gravitational collapse gravitational constant (G) gravitational instability gravitational lens gravitational life gravitational lock gravitational microlensing GRAVITATIONAL PHYSICS gravitational slingshot effect gravitational waves graviton gravity gravity gradient gravity gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) gray goo gray matter grazing - incidence telescope Great Annihilator Great Attractor great circle Great Comets Great Hercules Cluster (M13, NGC 6205) Great Monad Great Observatories Great Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases Green's theorem Greg, Percy (1836 — 1889) Gregorian calendar Grelling's paradox Griffith, George (1857 — 1906) Griffith Observatory Grignard, François Auguste Victor (1871 — 1935) Grignard reagent grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track group group theory GROUPS AND GROUP THEORY growing season growth growth hormone growth hormone - releasing hormone growth plate Grudge, Project Gruithuisen, Franz von Paula (1774 — 1852) Grus (constellation) Grus Quartet (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH215)
Dynamical effects (
changes in the winds and ocean
circulation) can have just as large an impact, locally as the radiative
forcing from greenhouse gases.
And a proper discussion of climate
change often does call for precise terms like external
forcing and general
circulation models, and other non-toddler friendly jargon.
Suppose also that — DESPITE THIS STABILIZING MECHANISM some as - yet unknown ocean
circulation cycle operates that is the sole cause of the Holocene centennial scale fluctuations, and that this cycle has reversed and is operating today, yielding a temperature
change that happens to mimic what models give in response to radiative
forcing changes.
«What warming there has been, has been almost entirely due to
changes in the
circulation, and not due to anthropogenic
forcing.»
16) models with prescribed anthropogenic
forcing show no similar
circulation changes related to the North Atlantic Oscillation or associated tropospheric warming.
Wood, R.A., A.B. Keen, J.F.B. Mitchell, and J.M. Gregory, 1999:
Changing spatial structure of the thermohaline
circulation in response to atmospheric CO2
forcing in a climate model.
The top priorities should be reducing uncertainties in climate sensitivity, getting a better understanding of the effect of climate
change on atmospheric
circulation (critical for understanding of regional climate
change,
changes in extremes) and reducing uncertainties in radiative
forcing — particularly those associated with aerosols.
This pack includes: 15 x Science songs (mp3) 15 x Instrumental versions (mp3) 15 x Lyrics in one handy document (pdf) Adaptation (Introduction)
Changing State
Circulation and Pulse Rate Earth, Sun and The Moon Electricity Evolution Feel the
Forces Healthy Eating Heat Light and Shadows Mixing Materials Plants Skeleton and Bones Sound Teeth www.mracdpresent.com
Indeed, one of the findings in the recent paper by Overpeck et al. (this weeks Science), is that even as the Greenland ice sheet melts faster than originally expected, it still won't provide sufficient meltwater
forcing of the North Atlantic
circulation (which is the feature of the climate system most commonly implicated in the discussion of «tipping points») to
force any sort of threshold
change.
Secondly, if the potential cloud response is related to
changes in
circulation caused by the TSI or an ozone related
change, then it isn't an extra
forcing at all — it is part of the feedback, and should already be incorporated in models.
In a series of papers, we've shown that the warmer temperatures observed over the WAIS are the result of those same atmospheric
circulation changes, which are not related to the SAM, but rather to the remote
forcing from
changes in the tropical Pacific:
changes in the character of ENSO (Steig et al., 2012; Ding et al., 2011; 2012).
For weather predictions, accuracy disappears within a few weeks — but for ocean forecasts, accuracy seems to have decadal scale accuracy — and when you go to climate
forcing effects, the timescale moves toward centuries, with the big uncertainties being ice sheet dynamics,
changes in ocean
circulation and the biosphere response.
For example: could different oceanic
circulation rates
change the oceanic CO2 sink / source behaviour, or could different atmospheric conditions
change the mixing rates of atmospheric gases hence modify their affect on the solar
forcing?
Suppose also that — DESPITE THIS STABILIZING MECHANISM some as - yet unknown ocean
circulation cycle operates that is the sole cause of the Holocene centennial scale fluctuations, and that this cycle has reversed and is operating today, yielding a temperature
change that happens to mimic what models give in response to radiative
forcing changes.
Since El Nino also has an important impact on the Asian Summer Monsoon in particular, its hard to know precisely what large - scale
changes in atmospheric
circulation are due to the radiative
forcing of the eruption itself, and the secondary response to that eruption of ENSO.
Some attribution assessments that link events to dynamically driven
changes in
circulation have been criticized on the grounds that small signal - to - noise ratios, modeling deficiencies, and uncertainties in the effects of climate
forcings on
circulation render conclusions unreliable and prone to downplaying the role of anthropogenic
change.
The basic issue is that nudging surface temperatures in the North Atlantic closer to observed data would probably nudge the Atlantic overturning
circulation in the wrong direction since
changing the temperature without
changing the salinity will give the opposite buoyancy
forcing to what would be needed.
On the other hand, there is no reason to believe that the Walker
circulation should
change smoothly as a function of climate
forcings; perhaps the potential for
change builds up over many years, and manifests itself all of a sudden, in the fashion of an avalanche.
There is so little understanding about how the ocean parses its response to
forcings by 1) suppressing (local convective scale) deep water formation where excessive warming patterns are
changed, 2) enhancing (local convective scale) deep water formation where the
changed excessive warming patterns are co-located with increased evaporation and increased salinity, and 3) shifting favored deep water formation locations as a result of a) shifted patterns of enhanced warming, b) shifted patterns of enhanced salinity and c) shifted patterns of
circulation which transport these enhanced ocean features to critically altered destinations.
«What warming there has been, has been almost entirely due to
changes in the
circulation, and not due to anthropogenic
forcing.
Many feedbacks, such as
changes in atmospheric moisture, cloudiness, and atmospheric
circulation should be similar for most
forcings.
Other
forcings, including the growth and decay of massive Northern Hemisphere continental ice sheets,
changes in atmospheric dust, and
changes in the ocean
circulation, are not likely to have the same kind of effect in a future warming scenario as they did at glacial times.
part of the utility is that Charney sensitivity, using only relatively rapid feedbacks, describes the climate response to an externally imposed
forcing change on a particular timescale related to the heat capacity of the system (if the feedbacks were sufficiniently rapid and the heat capacity independent of time scale (it's not largely because of oceanic
circulation), an imbalance would exponentially decay on the time scale of heat capacity * Charney equilibrium climate sensitivity.
I clearly see that the
change in surface temperature and TOA radiative
forcing simulated by the model depends upon the model complexity, for example, how the ocean
circulations are represented.
Zhang, R., 2010: Northward intensification of anthropogenically
forced changes in the Atlantic meridional overturning
circulation (AMOC).
Abstract: «The patterns of time / space
changes in near - surface temperature due to the separate
forcing components are simulated with a coupled atmosphere — ocean general
circulation model»
They are used to investigate the processes responsible for maintaining the general
circulation and its natural and
forced variability (Chapter 8), to assess the role of various
forcing factors in observed climate
change (Chapter 9) and to provide projections of the response of the system to scenarios of future external
forcing (Chapter 10).
To investigate the effects of CO2 emissions on ocean pH, we
forced the Lawrence Livermore National Laboratory ocean general -
circulation model (Fig. 1a) with the pressure of atmospheric CO2 (pCO2) observed from 1975 to 2000, and with CO2 emissions from the Intergovernmental Panel on Climate
Change's IS92a scenario1 for 2000 — 2100.
If the objective was to develop a general
circulation model that matches reality rather than to push an agenda likely one of model fixes would be modify to GCMs (modeling of planetary cloud cover) to match Lindzen and Choi finding that planetary cloud cover in the tropics increases or decreases to resist
forcing changes by reflecting more or less radiation off to space.
If the understanding of the dynamical aspects of he ODS
forced stratosphere are also correct in theory, expectations are the
circulation changes in the SH will revert to their pre 1976 Behavior,
«
Changing Spatial Structure of the Thermohaline
Circulation in Response to Atmospheric CO2
Forcing in a Climate Model.»
Oddly Trenberth 2015 argued we should separate analyses of those most useful dynamics and focus on thermodynamics (temperature) because CO2
forced circulation models do a very poor job of simulating those critical dynamic
changes.
In fact, they may do so more efficiently than more uniform temperature
change; warming one hemisphere with respect to the other is an excellent way of pulling monsoonal
circulations and oceanic ITCZs towards the warm hemisphere (the last few years have seen numerous studies of this response, relevant for ice ages and aerosol
forcing as well as the response to high latitude internal variability; Chiang and Bitz, 2005 is one of the first to discuss this, in the ice age context; I'll try to return to this topic in a future post.)
In a recent technical comment, Zhang et al. show that ocean dynamics play a central role in the Atlantic Multidecadal Oscillation (AMO), and the previous claims that «the AMO is a thermodynamic response of the ocean mixed layer to stochastic atmospheric
forcing, and ocean
circulation changes have no role in causing the AMO» are not justified.
Using 40 simulations of the 1920 - 2100 climate (Figure), the study found that northeast US sea level
changes can be partitioned into: (1) an interannual, internal, locally wind - driven component and (2) a multidecadal - to - centennial component that is associated with external
forcing and the overturning
circulation.
Current global multi-decadal predictions are unable to skillfully simulate regional
forcing by major atmospheric
circulation features such as from El Niño and La Niña and the South Asian monsoon, much less
changes in the statistics of these climate features.
Because radiative
forcing, while it does vary somewhat with vertical profile, is relatively immune to
changes of the atmosphere due to
circulation, so models can do a reasonable job of predicting that the global mean temperatures increase.
It is emergent behviour in a complex dynamical system characterised by
changes in ocean and atmospheric
circulation and consequential
changes in cloud radiative
forcing.
Of course the slow
changing Milankovitch
forcing can also emerge from the short - term noise over several millennia (or faster when ocean
circulation or glacial - melt tipping points are reached).
For my PhD research, I am working in Dr. Gudrun Magnusdottir's Research Group to apply a series of GCM ensemble experiments to understand the dynamics and relative
forcings of natural and anthropogenic climate
change on this high latitude
circulation and resultant teleconnection.
Using radiation modeling we estimated how strong the climate
forcing would be for each scenario, and then ran general
circulation models to see how that
forcing would
change the climate.
Anomalies in the volcanic - aerosol induced global radiative heating distribution can
force significant
changes in atmospheric
circulation, for example, perturbing the equator - to - pole heating gradient (Stenchikov et al., 2002; Ramaswamy et al., 2006a; see Section 9.2) and
forcing a positive phase of the Arctic Oscillation that in turn causes a counterintuitive boreal winter warming at middle and high latitudes over Eurasia and North America (Perlwitz and Graf, 2001; Stenchikov et al., 2002, 2004, 2006; Shindell et al., 2003b, 2004; Perlwitz and Harnik, 2003; Rind et al., 2005; Miller et al., 2006).
Here we use an ensemble of simulations with a coupled ocean — atmosphere model to show that the sea surface temperature anomalies associated with central Pacific El Niño
force changes in the extra-tropical atmospheric
circulation.
Once the sign of the solar effect on the stratosphere is reversed it becomes possible to propose a system of climate
change arising simply from the latitudinal shifting of the air
circulation systems in response to competing
forces from variable oceanic and solar cycles.
Since the ocean surface temperature is always greater than the deep ocean temperature, no
change in «surface»
forcing is required to
change the rate of ocean heat uptake, just
changes in «average»
circulation factors.