tropical regional precipitation anomalies: global warming...
TRANSCRIPT
![Page 1: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/1.jpg)
TROPICAL REGIONALTROPICAL REGIONALPRECIPITATION ANOMALIES:PRECIPITATION ANOMALIES:Global warming and El Global warming and El NiNiñoo casescasesJ. David J. David NeelinNeelin**, , HuiHui SuSu** and and ChiaChia ChouChou****
*Dept. of Atmospheric Sciences & Inst. of Geophysics and Planetary Physics, U.C.L.A.,
**Inst. of Earth Sciences, Academia Sinica, Taiwan
• Tropical regional precipitation anomalies associated with changes in deep convection zones: including drought regions in global warming case; mechanisms?; any similarities in El Niño case?
• Intermediate complexity climate model QTCM (Quasi-equilibrium Tropical Circulation Model)www.atmos.ucla.edu/~csi
![Page 2: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/2.jpg)
Observed anomalies during JulyObserved anomalies during July--Nov 1997Nov 1997
Precipitation(mm/day)
TroposphericTemperature
![Page 3: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/3.jpg)
QTCM anomalies forced by Pacific positive SST QTCM anomalies forced by Pacific positive SST anomalies Julyanomalies July--Nov 1997Nov 1997
Precipitation(mm/day)
TroposphericTemperature
![Page 4: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/4.jpg)
QTCM JulyQTCM July--Nov 1997: Anomaly budget contributionsNov 1997: Anomaly budget contributions11
Moisture convergence
Mq∇·v(by divergent flow)
Moist staticenergy
divergence*
M∇·v
* Gross moist stability M=Ms–Mq is an effective stability that includespartial cancellation of adiabatic cooling by diabatic heating
![Page 5: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/5.jpg)
QTCM JulyQTCM July--Nov 1997: Anomaly budget contributionsNov 1997: Anomaly budget contributions22
Radiative cooling anom. (top of
atmosphere) due to temp. anom.
Mean wind advection of
moisture anomalyv·∇q'
![Page 6: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/6.jpg)
ENSO ENSO teleconnectionsteleconnections to regional to regional precipprecip. anomalies. anomalies
![Page 7: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/7.jpg)
ENSO ENSO teleconnectionsteleconnections to regional to regional precipprecip. anomalies. anomalies
• a small zoo of mechanisms with moist convective and cloud radiative feedbacks
![Page 8: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/8.jpg)
QTCM experiments suppressing various mechanismsQTCM experiments suppressing various mechanismsPrecipitation Anomalies
Control
Anomaly ( )' term suppressed in region:
(v · ∇q)'
T' contribution toCAPE
![Page 9: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/9.jpg)
GCM GCM PrecipPrecip. . AnomAnom. Dec. Dec--FebFeb
Global warming case precipitation anom.
Greenhouse gas scenarios for
2070-2090rel. to 1961-1990 clim
![Page 10: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/10.jpg)
QTCM doubled COQTCM doubled CO22 experimentsexperimentsQfluxQflux mixedmixed--layer oceanlayer ocean
Dec - Feb Precip change
Dec - Feb QTCM Precip
climatology
![Page 11: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/11.jpg)
QTCM doubled COQTCM doubled CO22 experimentsexperimentsMoisture budget contributionsMoisture budget contributions11
Mq' ∇·v
Anomalous moisture convergence due to
moisture anom. q'
(v·∇q)'
Anomalous moisture advection
![Page 12: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/12.jpg)
QTCM doubled COQTCM doubled CO22 experimentsexperimentsMoisture budget contributionsMoisture budget contributions22
Mq ∇·v'
Anomalous moisture convergence due to
anomalous divergence (feedback)
![Page 13: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/13.jpg)
The “uppedThe “upped--ante” mechanismante” mechanism11
Margin of convective zone with v inward
from dry region
![Page 14: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/14.jpg)
The “uppedThe “upped--ante” mechanismante” mechanism22
Margin of convective zone with v inward
from dry region
![Page 15: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/15.jpg)
Anomalous Gross Moist Stability (MAnomalous Gross Moist Stability (M'') mechanism) mechanism
• Moist static energy transport by divergent flow ≈ M∇·v• M =Ms-Mq
• M∇·v' + M'∇·v = F'net - (v·∇q)' + …
• P' ≈ ∇·v(-M')
• Mechanism increases convergence & precip. in strong convergence zones: “rich-get-richer”
may partially compensate if cloud top risesincreases with increasing moisture, tends to reduce M
increases to compensatereduced
MMq
![Page 16: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/16.jpg)
QTCM 2xCOQTCM 2xCO22 ExptExpt. suppressing change in . suppressing change in moisture advectionmoisture advection
(testing the upped-ante mechanism)
Experiment2xCO2 Precip. change
(mm/day)
Control2xCO2 Precip. change
![Page 17: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/17.jpg)
QTCM 2xCOQTCM 2xCO22 ExptExpt. suppressing change in gross . suppressing change in gross moist stability, Mmoist stability, M
(testing the M' mechanism)
Experiment2xCO2 Precip. change
(mm/day)
Control2xCO2 Precip. change
![Page 18: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/18.jpg)
SummarySummary• analysis of tropical regional precipitation anomalies in ENSO
teleconnection case ⇒ a handful of contributing mechanisms• 2XCO2 case, mixed-layer ocean case ⇒ set of mechanisms with
some cross-over to ENSO case• the "upped-ante mechanism":
contributes substantial negative precipitation anomalyregions in both casesdrought occurs at margins of convection zones with
climatological wind inflow from dry zone into convection zone• the "anomalous gross moist stability (M') mechanism":
contributes positive precipitation changes in strong precipitation regions in global warming case (rich-get-richer)but theory for M' is very poor
• caveat Tropical mean precipitation anomaly mechanisms appear to differ between ENSO and global warming cases
![Page 19: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/19.jpg)
SummarySummary• analysis of tropical regional precipitation anomalies in ENSO
teleconnection case ⇒ a handful of contributing mechanisms• 2XCO2 case, mixed-layer ocean case ⇒ set of mechanisms with
some cross-over to ENSO case• the "upped-ante mechanism":
contributes substantial negative precipitation anomalyregions in both casesdrought occurs at margins of convection zones with
climatological wind inflow from dry zone into convection zone• the "anomalous gross moist stability (M') mechanism":
contributes positive precipitation changes in strong precipitation regions in global warming case (rich-get-richer)but theory for M' is very poor
• caveat Tropical mean precipitation anomaly mechanisms appear to differ between ENSO and global warming cases
![Page 20: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/20.jpg)
MOIST DYNAMICAL FEEDBACKS INMOIST DYNAMICAL FEEDBACKS INTROPICAL CLIMATE SENSITIVITY:TROPICAL CLIMATE SENSITIVITY:
ENSO vs. Global warmingENSO vs. Global warmingJ. David J. David NeelinNeelin**, , HuiHui SuSu** and and ChiaChia ChouChou****
*Dept. of Atmospheric Sciences & Inst. of Geophysics and Planetary Physics, U.C.L.A.,
**Inst. of Earth Sciences, Academia Sinica, Taiwan
• Tropical regional precipitation changes associated with shifts of or anomalies within deep convection zones: mechanisms for ENSO case; any similarities in global change case?
• Intermediate complexity climate model QTCM (Quasi-equilibrium Tropical Circulation Model)www.atmos.ucla.edu/~csi
![Page 21: TROPICAL REGIONAL PRECIPITATION ANOMALIES: Global warming ...atmos.ucla.edu/~csi/PPT/telecon_glbwrm.pdf · Global warming and El . NiñNi o. cases. J. David . Neelin *, Hui Su * and](https://reader035.vdocuments.net/reader035/viewer/2022070905/5f74b7a220160b30b64871af/html5/thumbnails/21.jpg)
TROPICAL PRECIPITATION ANOMALIES:TROPICAL PRECIPITATION ANOMALIES:ENSO TELECONNECTIONS VS.ENSO TELECONNECTIONS VS.
GLOBAL WARMINGGLOBAL WARMINGJ. David J. David NeelinNeelin**, , HuiHui SuSu** and and ChiaChia ChouChou****
*Dept. of Atmospheric Sciences & Inst. of Geophysics and Planetary Physics, U.C.L.A.,
**Inst. of Earth Sciences, Academia Sinica, Taiwan
• Tropical regional precipitation changes associated with shifts of or anomalies within deep convection zones: any similarity of mechanisms for ENSO and global change cases?
• Intermediate complexity climate model QTCM (Quasi-equilibrium Tropical Circulation Model)
www.atmos.ucla.edu/~csi