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Earth's Systems / Energy flow / Heat redistribution by air and ocean / Jet streams, storm tracks, monsoons and tropical cyclones

Jet streams, storm tracks, monsoons and tropical cyclones

How the pole-to-equator temperature contrast and rotation make jet streams and storm tracks, how the seasonal shift of tropical rain makes monsoons, and how tropical cyclones form as heat engines over warm oceans.

Boundary: where this process starts

Starts with: The equator-to-pole temperature contrast plus Earth's rotation make westerly jet streams near the tropopause (thermal wind)

Boundary: where it ends

Ends after: With warming the jets shift poleward: about 2 degrees in the Southern Hemisphere and 1 degree in the Northern jets by 2100 under RCP8.5, the Southern jet also s; Monsoons: in summer the tropical rain belt migrates over heated land, reversing surface winds and bringing the rainy season (global monsoon)

PARTICIPANTSRESOURCESJet streamAtmosphereMid-latitudestormsTropicalcyclonesStormsHeatWater vapourImpact +4 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +4 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +2 of 5. Click for details and evidence.Impact -2 of 5. Click for details and evidence.Impact +4 of 5. Click for details and evidence.Impact +4 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +4 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.The equator-to-pole temperature contrast plus Earth's rotation make westerly jet streams near the tropopause (thermal wind): uses HeatA subtropical jet sits at the poleward edge of the Hadley cell near 30 degrees; an eddy-driven jet in mid-latitudes is maintained by the storms themselves: uses HeatMid-latitude cyclones grow on strong temperature gradients and travel along storm tracks steered by the jet, carrying heat and moisture poleward: uses HeatMid-latitude cyclones grow on strong temperature gradients and travel along storm tracks steered by the jet, carrying heat and moisture poleward: uses Water vapourWith warming the jets shift poleward: about 2 degrees in the Southern Hemisphere and 1 degree in the Northern jets by 2100 under RCP8.5, the Southern jet also s: uses HeatArctic amplification weakens the poleward temperature gradient, slowing eastward Rossby-wave progression and the jet (contested): uses HeatMonsoons: in summer the tropical rain belt migrates over heated land, reversing surface winds and bringing the rainy season (global monsoon): uses HeatMonsoons: in summer the tropical rain belt migrates over heated land, reversing surface winds and bringing the rainy season (global monsoon): uses Water vapourTropical cyclones form over ocean warmer than 26 C down to about 50 m, more than about 500 km from the equator, with low wind shear, a moist mid-troposphere and: uses HeatTropical cyclones form over ocean warmer than 26 C down to about 50 m, more than about 500 km from the equator, with low wind shear, a moist mid-troposphere and: uses Water vapourA mature cyclone runs as a Carnot heat engine: it draws heat from the warm sea, releases latent heat in the eyewall and exhausts it near the tropopause: uses up Heatuses upA mature cyclone runs as a Carnot heat engine: it draws heat from the warm sea, releases latent heat in the eyewall and exhausts it near the tropopause: uses up Water vapouruses upWith 2 C of warming, cyclone rain rates rise about 14%, peak winds about 5% and the share of category 4-5 storms about 13%; translation speed already slowed 10%: uses HeatWith 2 C of warming, cyclone rain rates rise about 14%, peak winds about 5% and the share of category 4-5 storms about 13%; translation speed already slowed 10%: uses Water vapourusesHeat: usesusesHeat: usesusesHeat: usesusesWater vapour: usesusesHeat: usesusesHeat: usesusesHeat: usesusesWater vapour: usesusesHeat: usesusesWater vapour: usesuses upHeat: uses upuses upWater vapour: uses upusesHeat: usesusesWater vapour: usesStart: Jet streams,storm tracks, monsoonsand tropical cyclonesSTARTStart: Jet streams, storm tracks, monsoons and tropical cyclonesEnd: Jet streams, stormtracks, monsoons andtropical cyclonesENDEnd: Jet streams, storm tracks, monsoons and tropical cyclonesThe equator-to-poletemperature contrastplus Earth's rotati…📄2The equator-to-pole temperature contrast plus Earth's rotation make westerly jet streams near the tropopause (thermal wind)A subtropical jet sitsat the poleward edge ofthe Hadley cell near …📄2A subtropical jet sits at the poleward edge of the Hadley cell near 30 degrees; an eddy-driven jet in mid-latitudes is maintained by the storms themselvesMid-latitude cyclonesgrow on strongtemperature gradien…📄1 ↗1Mid-latitude cyclones grow on strong temperature gradients and travel along storm tracks steered by the jet, carrying heat and moisture polewardWith warming the jetsshift poleward: about 2degrees in the Southe…📄3With warming the jets shift poleward: about 2 degrees in the Southern Hemisphere and 1 degree in the Northern jets by 2100 under RCP8.5, the Southern jet also sArctic amplificationweakens the polewardtemperature gradien…📄1Arctic amplification weakens the poleward temperature gradient, slowing eastward Rossby-wave progression and the jet (contested)Monsoons: in summer thetropical rain beltmigrates over heat…📄2Monsoons: in summer the tropical rain belt migrates over heated land, reversing surface winds and bringing the rainy season (global monsoon)Tropical cyclones formover ocean warmer than26 C down to about …📄2Tropical cyclones form over ocean warmer than 26 C down to about 50 m, more than about 500 km from the equator, with low wind shear, a moist mid-troposphere andA mature cyclone runsas a Carnot heatengine: it draws he…📄2A mature cyclone runs as a Carnot heat engine: it draws heat from the warm sea, releases latent heat in the eyewall and exhausts it near the tropopauseWith 2 C of warming,cyclone rain rates riseabout 14%, peak win…📄4With 2 C of warming, cyclone rain rates rise about 14%, peak winds about 5% and the share of category 4-5 storms about 13%; translation speed already slowed 10%
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
What am I looking at? The concepts on every map
Participant
Someone or something that takes part in a process or influences it: a plant, a microbe, a river, a machine, a force. Participants are the rows of a map.
Resource
Something a step uses or uses up: water, oxygen, sunlight, a tool. Each step has an arrow down to the resources it uses.
Step
One thing that happens in a process. Every step has at least one participant and carries evidence.
Decision fork
A step where the process can go several ways. Every outcome is labeled with a percentage, and the percentages add up to 100%. It is not limited to yes or no.
Loop
A line that carries the process back to an earlier step. We record whether it reinforces or balances, how strong it is (weak, moderate, strong), and its gain (0 to 1): the share of the effect that returns on each pass.
Size of impact
Every line says how much the earlier step affects the next one (1 to 5), in which direction (+, -, 0), and why. Thicker lines mean bigger impact.
Evidence
The support for a claim: a source and what it shows. Every step, line, change and vote needs it. Click any step or line to read its evidence.
Boundary
Where a process starts and where it ends. Every process, and every subprocess, has a start and an end.
Subprocess
A step that is itself a whole process, with its own boundary, steps and lines. Click a step marked ↘ to open it. Subprocesses nest as deep as the evidence goes.
Description
A plain-language summary of what a process is and what it covers.
Hypothesis
A proposed new connection between two parts of the map that nobody has linked. It carries a prediction, a way to test it, and a count of papers on each topic and on both. It is an unverified idea until someone tests it.

Every step, with its evidence

The same information as the map, as a list you can search and share. Click a participant or resource to see everywhere it appears.

The equator-to-pole temperature contrast plus Earth's rotation make westerly jet streams near the tropopause (thermal wind)
Jet streamAtmosphereCoriolis effectHeat
Evidence (2) · added by Briangold-Claude
  • Shaw et al. 2016, Storm track processes and the opposing influences of climate change, Nature Geoscience 9:656-664, https://www.nature.com/articles/ngeo2783: Cyclones form where surface temperature gradients are large and the jet stream sets their speed and direction; the jet is tied to the meridional temperature gradient. (confidence 0.8)
  • Francis & Vavrus 2012, Evidence linking Arctic amplification to extreme weather in mid-latitudes, Geophys. Res. Lett. 39:L06801, https://doi.org/10.1029/2012GL051000: Relaxation of poleward thickness (temperature) gradients weakens upper-level zonal winds, showing the jet's dependence on the temperature contrast. (confidence 0.75)
A subtropical jet sits at the poleward edge of the Hadley cell near 30 degrees; an eddy-driven jet in mid-latitudes is maintained by the storms themselves
Jet streamHadley cellMid-latitude stormsHeat
Evidence (2) · added by Briangold-Claude
  • Woollings, Hannachi & Hoskins 2010, Variability of the North Atlantic eddy-driven jet stream, Q. J. R. Meteorol. Soc. 136:856-868, https://doi.org/10.1002/qj.625: The North Atlantic eddy-driven jet is distinct from the subtropical jet and varies in latitude, maintained by eddy momentum fluxes. (confidence 0.8)
  • Barnes & Polvani 2013, Response of the midlatitude jets, and of their variability, to increased greenhouse gases in the CMIP5 models, J. Climate 26:7117-7135, https://doi.org/10.1175/JCLI-D-12-00536.1: Midlatitude eddy-driven jets in the North Atlantic, North Pacific and Southern Hemisphere are analysed separately from the subtropical jet. (confidence 0.8)
Mid-latitude cyclones grow on strong temperature gradients and travel along storm tracks steered by the jet, carrying heat and moisture poleward
Mid-latitude stormsJet streamHeatWater vapour
Evidence (1) · added by Briangold-Claude
  • Shaw et al. 2016, Storm track processes and the opposing influences of climate change, Nature Geoscience 9:656-664, https://www.nature.com/articles/ngeo2783: Cyclones tend to form where surface temperature gradients are large; storm tracks shape the global climate through transport of energy and momentum. (confidence 0.9)
With warming the jets shift poleward: about 2 degrees in the Southern Hemisphere and 1 degree in the Northern jets by 2100 under RCP8.5, the Southern jet also s
Jet streamGreenhouse gasesHeat
Evidence (3) · added by Briangold-Claude
  • Barnes & Polvani 2013, Response of the midlatitude jets, and of their variability, to increased greenhouse gases in the CMIP5 models, J. Climate 26:7117-7135, https://doi.org/10.1175/JCLI-D-12-00536.1: All CMIP5 jets migrate poleward: the Southern Hemisphere jet by 2 degrees of latitude by the end of the century under RCP8.5, both Northern Hemisphere jets by only 1 degree; the Southern jet speeds up by 1.2 m/s. (confidence 0.85)
  • IPCC AR6 WG1 2021, Chapter 4: Future Global Climate, https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-4/: In the long term the Southern Hemisphere mid-latitude jet is likely to shift poleward and strengthen under SSP5-8.5 relative to 1995-2014. (confidence 0.85)
  • Vallis et al. 2015, Response of the large-scale structure of the atmosphere to global warming, Q. J. R. Meteorol. Soc. 141:1479-1501, https://doi.org/10.1002/qj.2456: There is a general poleward shift in surface westerlies in CMIP5 under warming. (confidence 0.75)
Arctic amplification weakens the poleward temperature gradient, slowing eastward Rossby-wave progression and the jet (contested)
ArcticJet streamAtmosphereHeat
Evidence (1) · added by Briangold-Claude
  • Francis & Vavrus 2012, Evidence linking Arctic amplification to extreme weather in mid-latitudes, Geophys. Res. Lett. 39:L06801, https://doi.org/10.1029/2012GL051000: Arctic amplification is linked to weakened upper-level zonal winds and larger-amplitude, slower-progressing Rossby waves, especially in autumn and winter; the strength of this link is debated. (confidence 0.65)
Monsoons: in summer the tropical rain belt migrates over heated land, reversing surface winds and bringing the rainy season (global monsoon)
MonsoonLand surfaceAtmosphereWater vapourHeat
Evidence (2) · added by Briangold-Claude
  • Geen et al. 2020, Monsoons, ITCZs, and the concept of the global monsoon, Rev. Geophys. 58:e2020RG000700, https://doi.org/10.1029/2020RG000700: The global monsoon is a solstitial mode of the tropical overturning: seasonal migration of the convergence zone over continents, with regional monsoons localized by land-sea contrast and orography. (confidence 0.85)
  • Wang & Ding 2008, Global monsoon: Dominant mode of annual variation in the tropics, Dyn. Atmos. Oceans 44:165-183, https://doi.org/10.1016/j.dynatmoce.2007.05.002: The global monsoon is the dominant mode of annual variation of tropical precipitation and circulation. (confidence 0.75)
Tropical cyclones form over ocean warmer than 26 C down to about 50 m, more than about 500 km from the equator, with low wind shear, a moist mid-troposphere and
Tropical cyclonesOceanCoriolis effectHeatWater vapour
Evidence (2) · added by Briangold-Claude
  • NOAA AOML Hurricane Research Division, Hurricane FAQ, https://www.aoml.noaa.gov/hrd-faq/: Requirements: ocean water of at least 26.5 C to about 50 m depth, an atmosphere that cools fast enough with height, a moist mid-troposphere, at least 500 km (300 miles) from the equator for enough Coriolis spin, low vertical wind shear and a pre-existing disturbance. (confidence 0.9)
  • NOAA National Ocean Service, How do hurricanes form?, https://oceanservice.noaa.gov/facts/how-hurricanes-form.html: A hurricane often starts as a tropical wave over water of at least 26 C. (confidence 0.85)
A mature cyclone runs as a Carnot heat engine: it draws heat from the warm sea, releases latent heat in the eyewall and exhausts it near the tropopause
Tropical cyclonesOceanHeatWater vapour
Evidence (2) · added by Briangold-Claude
  • Emanuel 1991, The theory of hurricanes, Annu. Rev. Fluid Mech. 23:179-196, https://doi.org/10.1146/annurev.fl.23.010191.001143: The mature hurricane can be idealised as a Carnot heat engine driven by the thermodynamic disequilibrium between the tropical ocean and atmosphere, with potential intensity set by sea surface and outflow temperatures. (confidence 0.9)
  • NOAA AOML Hurricane Research Division, Hurricane FAQ, https://www.aoml.noaa.gov/hrd-faq/: Warm ocean waters fuel the heat engine of the tropical cyclone. (confidence 0.8)
With 2 C of warming, cyclone rain rates rise about 14%, peak winds about 5% and the share of category 4-5 storms about 13%; translation speed already slowed 10%
Tropical cyclonesGreenhouse gasesHeatWater vapour
Evidence (4) · added by Briangold-Claude
  • Knutson et al. 2020, Tropical cyclones and climate change assessment: Part II, Bull. Amer. Meteor. Soc. 101:E303-E322, https://doi.org/10.1175/BAMS-D-18-0194.1: For 2 C warming: median projected increase of 14% in TC precipitation rates, about 5% in lifetime maximum winds, and +13% in the proportion reaching category 4-5. (confidence 0.9)
  • Kossin 2018, A global slowdown of tropical-cyclone translation speed, Nature 558:104-107, https://doi.org/10.1038/s41586-018-0158-3: Tropical-cyclone translation speed decreased globally by 10 per cent over 1949-2016. (confidence 0.85)
  • Knutson et al. 2010, Tropical cyclones and climate change, Nature Geoscience 3:157-163, https://www.nature.com/articles/ngeo779: Projections indicate intensity increases of 2-11% by 2100 and decreases in global frequency of 6-34%. (confidence 0.8)
  • Emanuel 2005, Increasing destructiveness of tropical cyclones over the past 30 years, Nature 436:686-688, https://doi.org/10.1038/nature03906: The power dissipation index of hurricanes has increased markedly since the mid-1970s, correlated with tropical SST. (confidence 0.75)