Abstract
Purpose of Review
Long-standing biases in simulations of past and present climate states and climate model disagreement even in sign of future monsoon rainfall changes evince limitations in our theoretical understanding.
Recent Findings
The dominant theoretical paradigms for understanding monsoon rainfall—convective-quasi equilibrium (CQE), the moist static energy (MSE) budget, and monsoons as local Intertropical Convergence Zone (ITCZ) shifts—all jettison the traditional “land-sea breeze” paradigm. Summer monsoon precipitation falls when the assumptions of CQE are most satisfied but those of the ITCZ shift framework are least satisfied. Zonal asymmetries, changes in ITCZ width and strength, hydrology-vegetation-CO2 coupling, and timescale-dependent responses complicate inferences of monsoon rainfall from paleoclimate proxy records. The MSE budget framework applied to deliberately designed simulations can illuminate key mechanisms underlying monsoon responses to external forcings, presenting a path toward falsifying model projections.
Summary
Sustained, rapid progress in monsoon rainfall theory is urgently needed by society and is plausible based on recent advances.
Similar content being viewed by others
References
Papers of particular interest, published recently, have been highlighted as: • Of importance
Indo-Asian News Service. India cheers as monsoon arrives; hopes of better farm output raised. Hindustan times. 2010 [cited 2015 Dec 31]; Available from: http://www.hindustantimes.com/india/india-cheers-as-monsoon-arrives-hopes-of-better-farm-output-raised/story-Og0hZJ0ULuibRu4y7CVFpO.html.
Adam O, Schneider T, Brient F, Bischoff T. Relation of the double-ITCZ bias to the atmospheric energy budget in climate models. Geophys Res Lett. 2016;43(14):2016GL069465.
Tierney JE, Pausata FSR, deMenocal PB. Rainfall regimes of the Green Sahara. Sci Adv. 2017;3(1):e1601503.
Haywood AM, Dowsett HJ, Dolan AM, Rowley D, Abe-Ouchi A, Otto-Bliesner B, et al. The Pliocene Model Intercomparison project (PlioMIP) phase 2: scientific objectives and experimental design. Clim Past. 2016;12(3):663–75.
Shepherd TG. Atmospheric circulation as a source of uncertainty in climate change projections. Nat Geosci. 2014;7(10):703–8.
Held IM, Soden BJ. Robust responses of the hydrological cycle to global warming. J Clim. 2006;19(21):5686–99.
• Hill SA, Ming Y, Held IM, Zhao M. A Moist Static Energy Budget–Based Analysis of the Sahel Rainfall Response to Uniform Oceanic Warming. J Clim. 2017;30(15):5637–60. Uses MSE budget to identify simple upped-ante-like mechanism of enhanced Saharan air advection that dries the Sahel under mean SST warming.
Schneider T, Teixeira J, Bretherton CS, Brient F, Pressel KG, Schär C, et al. Climate goals and computing the future of clouds. Nat Clim Chang. 2017;7(1):3–5.
Klein SA, Hall A. Emergent constraints for cloud feedbacks. Curr Clim Change Rep. 2015;1(4):276–87.
Emanuel KA, David Neelin J, Bretherton CS. On large-scale circulations in convecting atmospheres. QJR Meteorol Soc. 1994;120(519):1111–43.
Emanuel KA. On thermally direct circulations in moist atmospheres. J Atmos Sci. 1995;52(9):1529–34.
Nie J, Boos WR, Kuang Z. Observational evaluation of a convective quasi-equilibrium view of monsoons. J Clim. 2010;23(16):4416–28.
Neelin JD, Held IM. Modeling tropical convergence based on the moist static energy budget. Mon Weather Rev. 1987;115(1):3–12.
Chou C, Neelin JD, Su H. Ocean-atmosphere-land feedbacks in an idealized monsoon. QJR Meteorol Soc. 2001;127(576):1869–91.
Chou C, Neelin JD. Mechanisms limiting the southward extent of the south American summer monsoon. Geophys Res Lett. 2001;28(12):2433–6.
Chou C, Neelin JD. Mechanisms limiting the northward extent of the northern summer monsoons over North America, Asia, and Africa. J Clim. 2003;16(3):406–25.
• Biasutti M, Voigt A, Boos WR, Braconnot P, Hargreaves JC, Harrison SP, et al. Global energetics and local physics as drivers of past, present and future monsoons. Nat Geosci. 2018;11(6):392–400. Reviews the ITCZ energetic framework and other conceptual frameworks for monsoon precipitation, emphasizing potential of adapting the ITCZ shifts framework to zonally confined monsoons.
Diaz M, Boos WR. Barotropic growth of monsoon depressions. Q J R Meteorol Soc. 2019 [cited 2019 Jan 1];0(ja). Available from: https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/qj.3467.
Adames ÁF, Ming Y. Interactions between water vapor and potential vorticity in synoptic-scale monsoonal disturbances: moisture vortex instability. J Atmos Sci. 2018;75(6):2083–106.
Gadgil S. The monsoon system: land–sea breeze or the ITCZ? J Earth Syst Sci. 2018;127(1):1.
Bordoni S, Schneider T. Monsoons as eddy-mediated regime transitions of the tropical overturning circulation. Nat Geosci. 2008;1(8):515–9.
Zhou W, Xie S-P. A hierarchy of idealized monsoons in an intermediate GCM. J Clim. 2018;31(22):9021–36.
Hurley JV, Boos WR. Interannual variability of monsoon precipitation and local subcloud equivalent potential temperature. J Clim. 2013;26(23):9507–27.
Lindzen RS, Nigam S. On the role of sea surface temperature gradients in forcing low-level winds and convergence in the tropics. J Atmos Sci. 1987;44(17):2418–36.
Back LE, Bretherton CS. On the relationship between SST gradients, boundary layer winds, and convergence over the tropical oceans. J Clim. 2009;22(15):4182–96.
Sobel AH. Simple models of ensemble-averaged tropical precipitation and surface wind, given the sea surface temperature. In: The global circulation of the atmosphere. Princeton University Press; 2007. p. 219–51.
Schneider T, Bordoni S. Eddy-mediated regime transitions in the seasonal cycle of a Hadley circulation and implications for monsoon dynamics. J Atmos Sci. 2008;65(3):915–34.
Walker CC, Schneider T. Eddy influences on Hadley circulations: simulations with an idealized GCM. J Atmos Sci. 2006;63(12):3333–50.
Hill SA, Bordoni S, Mitchell JL. Axisymmetric constraints on cross-equatorial Hadley cell extent. J Atmos Sci. 2019 [cited 2018 Oct 30];Accepted. Available from: https://arxiv.org/abs/1810.11105.
Schneider EK. Axially symmetric steady-state models of the basic state for instability and climate studies. Part II. Nonlinear calculations. J Atmos Sci. 1977;34(2):280–96.
Held IM, Hou AY. Nonlinear axially symmetric circulations in a nearly inviscid atmosphere. J Atmos Sci. 1980;37(3):515–33.
Hsu CJ, Plumb RA. Nonaxisymmetric thermally driven circulations and upper-tropospheric monsoon dynamics. J Atmos Sci. 2000;57(9):1255–76.
Walker CC, Schneider T. Response of idealized Hadley circulations to seasonally varying heating. Geophys Res Lett. 2005;32(6):L06813.
Schneider T. The general circulation of the atmosphere. Annu Rev Earth Planet Sci. 2006;34:655–88.
Levine XJ, Schneider T. Response of the Hadley circulation to climate change in an Aquaplanet GCM coupled to a simple representation of ocean heat transport. J Atmos Sci. 2011;68(4):769–83.
Levine XJ, Schneider T. Baroclinic eddies and the extent of the Hadley circulation: an idealized GCM study. J Atmos Sci. 2015;72(7):2744–61.
Bordoni S, Schneider T. Regime transitions of steady and time-dependent Hadley circulations: comparison of axisymmetric and Eddy-permitting simulations. J Atmos Sci. 2010;67(5):1643–54.
Shaw TA. On the role of planetary-scale waves in the abrupt seasonal transition of the northern hemisphere general circulation. J Atmos Sci. 2014;71(5):1724–46.
Geen R, Lambert FH, Vallis GK. Regime change behavior during Asian monsoon onset. J Clim. 2018;31(8):3327–48.
Zhai J, Boos W. Regime transitions of cross-equatorial Hadley circulations with zonally asymmetric thermal Forcings. J Atmos Sci. 2015;72(10):3800–18.
Emanuel K. Inferences from simple models of slow, convectively coupled processes. J Atmos Sci. 2019;76(1):195–208.
Neelin JD, Zeng N. A Quasi-Equilibrium Tropical Circulation Model—Formulation. J Atmos Sci. 2000;57(11):1741–66.
Privé NC, Plumb RA. Monsoon dynamics with interactive forcing. Part I: axisymmetric studies. J Atmos Sci. 2007;64(5):1417–30.
Zhai J, Boos WR. The drying tendency of shallow meridional circulations in monsoons. QJR Meteorol Soc. 2017;143(708):2655–64.
Shekhar R, Boos WR. Weakening and shifting of the Saharan shallow meridional circulation during wet years of the West African monsoon. J Clim. 2017;30(18):7399–422.
Emanuel KA. The Lagrangian parcel dynamics of moist symmetric instability. J Atmos Sci. 1983;40(10):2368–76.
• Singh MS. Limits on the extent of the solsticial Hadley cell: the role of planetary rotation. J Atmos Sci. 2019;Submitted. Uses slantwise convective neutrality to generalize the Privé and Plumb 2007 diagnostic for the monsoon rainbelt position to cases with nonzero vertical zonal wind shear.
Adam O, Paldor N. Global circulation in an axially symmetric shallow-water Model, forced by off-equatorial differential heating. J Atmos Sci. 2010;67(4):1275–86.
Neelin JD, Chou C. Su H. tropical drought regions in global warming and El Niño teleconnections. Geophys Res Lett. 2003;30(24):2275.
Chou C, Neelin JD. Mechanisms of global warming impacts on regional tropical precipitation. J Clim. 2004;17(13):2688–701.
Chou C, Neelin JD, Lohmann U, Feichter J. Local and remote impacts of aerosol climate forcing on tropical precipitation. J Clim. 2005 [cited 2014 Apr 30];18(22). Available from: http://search.ebscohost.com/login.aspx?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=08948755&AN=19883071&h=uNl9092WFmofs5dY6nUpKqBCsGJU7xMZGFcPjThRJzihU5UQloJF4KlKg52KQsi9m65d9hKrM9pXha9tgO9BGw%3D%3D&crl=c.
Boos WR, Kuang Z. Dominant control of the south Asian monsoon by orographic insulation versus plateau heating. Nature. 2010;463(7278):218–22.
Trenberth KE. Climate diagnostics from global analyses: conservation of mass in ECMWF analyses. J Clim. 1991;4(7):707–22.
Peters ME, Kuang Z, Walker CC. Analysis of Atmospheric energy transport in ERA-40 and implications for simple models of the mean tropical circulation. J Clim. 2008;21(20):5229–41.
Neelin JD. Moist dynamics of tropical convection zones in monsoons, teleconnections, and global warming. In: The Global Circulation of the Atmosphere. Princeton University Press; 2007 [cited 2014 Apr 30]. p. 267–301. Available from: http://www.atmos.ucla.edu/~csi/REF/pdfs/gencircrev.pdf.
Zhao M. An Analysis of Global Climate Model Simulated Madden-Julian Oscillation with Fully Closed Moist Static Energy Budget. In: AMS; 2018 [cited 2019 Mar 11]. Available from: https://ams.confex.com/ams/33HURRICANE/webprogram/Paper338683.html.
Wing AA, Reed KA, Satoh M, Stevens B, Bony S, Ohno T. Radiative–convective equilibrium model intercomparison project. Geosci Model Dev. 2018;11(2):793–813.
• Hill SA, Ming Y, Zhao M. Robust Responses of the Sahelian Hydrological Cycle to Global Warming. J Clim. 2018;31(24):9793–814. Shows that enhanced Saharan air advection into the Sahel is robust across AGCMs under uniform SST warming and attempts to generate an emergent observational constraint based on this mechanism.
He J, Soden BJ. Does the lack of coupling in SST-forced atmosphere-only models limit their usefulness for climate change studies? J Clim. 2015;29(12):4317–25.
He J, Soden BJ. The impact of SST biases on projections of anthropogenic climate change: a greater role for atmosphere-only models? Geophys Res Lett. 2016;43(14):2016GL069803.
Pascale S, Boos WR, Bordoni S, Delworth TL, Kapnick SB, Murakami H, et al. Weakening of the north American monsoon with global warming. Nat Clim Chang. 2017;7(11):806–12.
Bony S, Bellon G, Klocke D, Sherwood S, Fermepin S, Denvil S. Robust direct effect of carbon dioxide on tropical circulation and regional precipitation. Nat Geosci. 2013;6(6):447–51.
Ma J, Xie S-P. Regional patterns of sea surface temperature change: a source of uncertainty in future projections of precipitation and Atmospheric circulation. J Clim. 2012;26(8):2482–501.
Chadwick R, Boutle I, Martin G. Spatial patterns of precipitation change in CMIP5: why the rich do not get richer in the tropics. J Clim. 2013;26(11):3803–22.
Chadwick R, Good P, Andrews T, Martin G. Surface warming patterns drive tropical rainfall pattern responses to CO2 forcing on all timescales. Geophys Res Lett. 2014;41(2):610–5.
Chadwick R. Which aspects of CO2 forcing and SST warming cause Most uncertainty in projections of tropical rainfall change over land and ocean? J Clim. 2016;29(7):2493–509.
Chadwick R, Douville H, Skinner CB. Timeslice experiments for understanding regional climate projections: applications to the tropical hydrological cycle and European winter circulation. Clim Dyn. 2017;49(9–10):3011–29.
Hill SA, Ming Y, Held IM. Mechanisms of forced tropical meridional energy flux change. J Clim. 2015;28(5):1725–42.
GFDL Atmospheric Model Development Team. The new GFDL global atmosphere and land Model AM2–LM2: evaluation with prescribed SST simulations. J Clim. 2004;17(24):4641–73.
Delworth TL, Broccoli AJ, Rosati A, Stouffer RJ, Balaji V, Beesley JA, et al. GFDL’s CM2 global coupled climate models. Part I: formulation and simulation characteristics. J Clim. 2006;19(5):643–74.
Ming Y, Ramaswamy V. Nonlinear climate and hydrological responses to aerosol effects. J Clim. 2009;22(6):1329–39.
Donner LJ, Wyman BL, Hemler RS, Horowitz LW, Ming Y, Zhao M, et al. The dynamical Core, physical parameterizations, and basic simulation characteristics of the Atmospheric component AM3 of the GFDL global coupled Model CM3. J Clim. 2011;24(13):3484–519.
Zhao M, Held IM, Lin S-J, Vecchi GA. Simulations of global hurricane climatology, interannual variability, and response to global warming using a 50-km resolution GCM. J Clim. 2009;22(24):6653–78.
Hwang Y-T, Frierson DMW, Kang SM. Anthropogenic sulfate aerosol and the southward shift of tropical precipitation in the late 20th century. Geophys Res Lett. 2013;40(11):2845–50.
Held IM, Delworth TL, Lu J, Findell KL, Knutson TR. Simulation of Sahel drought in the 20th and 21st centuries. PNAS. 2005;102(50):17891–6.
Kraus EB. The seasonal excursion of the intertropical convergence zone. Mon Weather Rev. 1977;105(8):1052–5.
Kraus EB. Subtropical droughts and cross-equatorial energy transports. Mon Weather Rev. 1977;105(8):1009–18.
Broccoli AJ, Dahl KA, Stouffer RJ. Response of the ITCZ to northern hemisphere cooling. Geophys Res Lett. 2006;33(1):L01702.
Kang SM, Frierson DMW, Held IM. The tropical response to extratropical thermal forcing in an idealized GCM: the importance of radiative feedbacks and convective parameterization. J Atmos Sci. 2009;66(9):2812–27.
Schneider T, Bischoff T, Haug GH. Migrations and dynamics of the intertropical convergence zone. Nature. 2014;513(7516):45–53.
Bischoff T, Schneider T. Energetic constraints on the position of the intertropical convergence zone. J Clim. 2014;27(13):4937–51.
Bischoff T, Schneider T. The equatorial energy balance, ITCZ position, and double-ITCZ bifurcations. J Clim. 2016;29(8):2997–3013.
Adam O, Bischoff T, Schneider T. Seasonal and interannual variations of the energy flux equator and ITCZ. Part I: zonally averaged ITCZ position. J Clim. 2016;29(9):3219–30.
Adam O, Bischoff T, Schneider T. Seasonal and interannual variations of the energy flux equator and ITCZ. Part II: zonally varying shifts of the ITCZ. J Clim. 2016;29(20):7281–93.
Green B, Marshall J. Coupling of trade winds with ocean circulation damps ITCZ shifts. J Clim. 2017;30(12):4395–411.
Schneider T. Feedback of Atmosphere-Ocean coupling on shifts of the intertropical convergence zone. Geophys Res Lett. 2017;44(22):2017GL075817.
Kang SM, Shin Y, Xie S-P. Extratropical forcing and tropical rainfall distribution: energetics framework and ocean Ekman advection. npj Clim Atmos Sci. 2018;1(1):2.
Frierson DMW, Hwang Y-T, Fučkar NS, Seager R, Kang SM, Donohoe A, et al. Contribution of ocean overturning circulation to tropical rainfall peak in the northern hemisphere. Nat Geosci. 2013;6(11):940–4.
Harrop BE, Hartmann DL. The role of cloud radiative heating in determining the location of the ITCZ in Aquaplanet simulations. J Clim. 2016;29(8):2741–63.
Clark SK, Ming Y, Held IM, Phillipps PJ. The role of the water vapor feedback in the ITCZ response to hemispherically asymmetric forcings. J Clim. 2018 [cited 2018 Apr 11]; Available from: http://journals.ametsoc.org/doi/10.1175/JCLI-D-17-0723.1.
• Byrne MP, Pendergrass AG, Rapp AD, Wodzicki KR. Response of the Intertropical Convergence Zone to Climate Change: Location, Width, and Strength. Curr Clim Change Rep. 2018;4(4):355–70. Demonstrate leading-order importance of ITCZ strength and width changes and consider how to better understand them.
Hilgenbrink CC, Hartmann DL. The response of Hadley circulation extent to an idealized representation of Poleward Ocean heat transport in an Aquaplanet GCM. J Clim. 2018;31(23):9753–70.
Watt-Meyer O, Frierson DMW. ITCZ width controls on Hadley cell extent and Eddy-driven jet position and their response to warming. J Clim. 2019;32(4):1151–66.
Held IM. The general circulation of the atmosphere. In: The general circulation of the atmosphere: 2000 program in geophysical fluid dynamics. Woods Hole Oceanographic Institution; 2000. p. 1–54. (Woods Hole Oceanog. Inst. Tech. Rept.).
Kang SM, Lu J. Expansion of the Hadley cell under global warming: winter versus summer. J Clim. 2012;25(24):8387–93.
Levine XJ, Boos WR. Land surface albedo bias in climate models and its association with tropical rainfall. Geophys Res Lett. 2017;44(12):2017GL072510.
Zhou W, Xie S-P. Intermodel spread of the double-ITCZ bias in coupled GCMs tied to land surface temperature in AMIP GCMs. Geophys Res Lett. 2017;44(15):2017GL074377.
Hwang Y-T, Frierson DMW. Link between the double-intertropical convergence zone problem and cloud biases over the Southern Ocean. PNAS. 2013;110(13):4935–40.
Xiang B, Zhao M, Held IM, Golaz J-C. Predicting the severity of spurious “double ITCZ” problem in CMIP5 coupled models from AMIP simulations. Geophys Res Lett. 2017;44(3):2016GL071992.
Smyth JE, Hill SA, Ming Y. Simulated responses of the West African monsoon and zonal-mean tropical precipitation to Early Holocene orbital forcing. Geophys Res Lett. 2018;45(21):12,049–57.
Liu X, Battisti DS, Donohoe A. Tropical precipitation and cross-Equatorial Ocean heat transport during the mid-Holocene. J Clim. 2017;30(10):3529–47.
Boos WR, Korty RL. Regional energy budget control of the intertropical convergence zone and application to mid-Holocene rainfall. Nature Geosci. 2016 [cited 2016 Nov 28];advance online publication. Available from: http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2833.html?cookies=accepted.
Donohoe A, Voigt A. Why Future Shifts in Tropical Precipitation Will Likely Be Small. In: Climate Extremes. American Geophysical Union (AGU); 2017 [cited 2019 Jan 8]. p. 115–37. Available from: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/9781119068020.ch8.
Shekhar R, Boos WR. Improving energy-based estimates of monsoon location in the presence of proximal deserts. J Clim. 2016;29(13):4741–61.
Kang SM, Held IM, Frierson DMW, Zhao M. The response of the ITCZ to extratropical thermal forcing: idealized Slab-Ocean experiments with a GCM. J Clim. 2008;21(14):3521–32.
Faulk S, Mitchell J, Bordoni S. Effects of rotation rate and seasonal forcing on the ITCZ extent in planetary atmospheres. J Atmos Sci. 2017;74(3):665–78.
Gonzalez AO, Slocum CJ, Taft RK, Schubert WH. Dynamics of the ITCZ boundary layer. J Atmos Sci. 2015;73(4):1577–92.
Gonzalez AO, Schubert WH. Violation of Ekman balance in the Eastern Pacific ITCZ boundary layer. J Atmos Sci. 2019;Submitted.
• Roberts WHG, Valdes PJ, Singarayer JS. Can energy fluxes be used to interpret glacial/interglacial precipitation changes in the tropics? Geophys Res Lett. 2017;44(12):2017GL073103. Demonstrates that relationships between zonal-mean ITCZ and energy transports can differ between seasonal cycle and forced, annual-mean changes and very weakly constrains local precipitation change for most tropical regions.
Held IM. The partitioning of the poleward energy transport between the Tropical Ocean and atmosphere. J Atmos Sci. 2001;58(8):943–8.
Merlis TM, Schneider T, Bordoni S, Eisenman I. Hadley circulation response to orbital precession. Part I: Aquaplanets. J Climate. 2013;26(3):740–53.
Wei H-H, Bordoni S. Energetic constraints on the ITCZ position in idealized simulations with a seasonal cycle. J Adv Model Earth Syst. 2018;10(7):1708–25.
Xiang B, Zhao M, Ming Y, Yu W, Kang SM. Contrasting impacts of radiative forcing in the Southern Ocean versus southern tropics on ITCZ position and energy transport in one GFDL climate Model. J Clim. 2018;31(14):5609–28.
Inoue K, Back LE. Gross moist stability assessment during TOGA COARE: various interpretations of gross moist stability. J Atmos Sci. 2015;72(11):4148–66.
Frierson DMW. The dynamics of idealized convection schemes and their effect on the zonally averaged tropical circulation. J Atmos Sci. 2007;64(6):1959–76.
Wheeler M, Kiladis GN. Convectively coupled equatorial waves: analysis of clouds and temperature in the wavenumber-frequency domain. J Atmos Sci. 1999;56(3):374–99.
Frierson DMW. Convectively coupled kelvin waves in an idealized moist general circulation Model. J Atmos Sci. 2007;64(6):2076–90.
Chen G, Held IM. Phase speed spectra and the recent poleward shift of Southern Hemisphere surface westerlies. Geophys Res Lett. 2007 [cited 2014 Apr 30];34(21). Available from: http://doi.wiley.com/10.1029/2007GL031200.
• Bischoff T, Schneider T, Meckler AN. A Conceptual Model for the Response of Tropical Rainfall to Orbital Variations. J Clim. 2017;30(20):8375–91. Presents conceptual model for tropical precipitation responses to orbital precession and obliquity forcing based in part on ITCZ shifts framework that captures many features of paleoclimate records at various individual sites.
Shanahan TM, McKay NP, Hughen KA, Overpeck JT, Otto-Bliesner B, Heil CW, et al. The time-transgressive termination of the African humid period. Nat Geosci. 2015;8(2):140–4.
• Boos WR, Storelvmo T. Near-linear response of mean monsoon strength to a broad range of radiative forcings. PNAS. 2016;113(6):1510–5. Identifies fundamental errors in previous simple theoretical models projecting monsoon “tipping points”, and demonstrates that monsoon responses in a GCM to widely varying forcings are very nearly linear.
• Scheff J, Seager R, Liu H, Coats S. Are Glacials Dry? Consequences for Paleoclimatology and for Greenhouse Warming. J Clim. 2017;30(17):6593–609. Shows that, for land, no single catch-all measure of “wetness” exists, and that plant stomatal responses to CO2 can cause commonly used indices of dryness to err.
Scheff J. Drought Indices, Drought Impacts, CO<Subscript>2</Subscript>, and Warming: a Historical and Geologic Perspective. Curr Clim Change Rep. 2018;4(2):202–9.
Swann ALS. Plants and drought in a changing climate. Curr Clim Change Rep. 2018;4(2):192–201.
Berg A, Sheffield J. Climate change and drought: the soil moisture perspective. Curr Clim Change Rep. 2018;4(2):180–91.
Timm O, Köhler P, Timmermann A, Menviel L. Mechanisms for the onset of the African humid period and Sahara greening 14.5–11 ka BP. J Clim. 2010;23(10):2612–33.
Siler N, Roe GH, Armour KC. Insights into the zonal-mean response of the hydrologic cycle to global warming from a diffusive energy balance Model. J Clim. 2018;31(18):7481–93.
Jansen MF, Nadeau L-P, Merlis TM. Transient versus equilibrium response of the Ocean’s overturning circulation to warming. J Clim. 2018;31(13):5147–63.
Burls NJ, Fedorov AV, Sigman DM, Jaccard SL, Tiedemann R, Haug GH. Active Pacific meridional overturning circulation (PMOC) during the warm Pliocene. Sci Adv. 2017;3(9):e1700156.
Zhang R, Delworth TL. Impact of Atlantic multidecadal oscillations on India/Sahel rainfall and Atlantic hurricanes. Geophys Res Lett. 2006;33(17):L17712.
Park J-Y, Bader J, Matei D. Northern-hemispheric differential warming is the key to understanding the discrepancies in the projected Sahel rainfall. Nat Commun. 2015;6:5985.
Seth A, Giannini A, Rojas M, Rauscher SA, Bordoni S, Singh D, et al. Monsoon responses to climate changes—connecting past, present and future. Curr Clim Change Rep. 2019;5(2):63–79.
Shepherd TG, Boyd E, Calel RA, Chapman SC, Dessai S, Dima-West IM, et al. Storylines: an alternative approach to representing uncertainty in physical aspects of climate change. Clim Chang. 2018;151(3):555–71.
Zhao M, Golaz J-C, Held IM, Guo H, Balaji V, Benson R, et al. The GFDL global atmosphere and land Model AM4.0/LM4.0: 1. Simulation characteristics with prescribed SSTs. J Adv Model Earth Syst. 2018;10(3):691–734.
Acknowledgments
I thank Yi Ming, Simona Bordoni, Jonathan Mitchell, Isaac Held, Ming Zhao, Natalie Burls, Martin Singh, Dargan Frierson, Bill Boos, Sarah Kang, Alex Gonzalez, Sean Faulk, David Neelin, Tim Merlis, Ho-Hsuan Wei, and Jack Scheff for conversations that have shaped my thinking on these topics. I also thank Michael Byrne and an anonymous reviewer for insightful reviews of the manuscript.
Funding
This work was supported by a Caltech Foster and Coco Stanback Postdoctoral Fellowship.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of Interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
This article is part of the Topical Collection on Climate Change and Atmospheric Circulation
Rights and permissions
About this article
Cite this article
Hill, S.A. Theories for Past and Future Monsoon Rainfall Changes. Curr Clim Change Rep 5, 160–171 (2019). https://doi.org/10.1007/s40641-019-00137-8
Published:
Issue Date:
DOI: https://doi.org/10.1007/s40641-019-00137-8