global&hydrological&cycle&response&...
TRANSCRIPT
![Page 1: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/1.jpg)
Global hydrological cycle response to rapid and slow global warming
Larissa Back, Kuniaki Inoue, Karen Russ, Zhengyu Liu
*Simulations implemented by Feng He and Jiaxu Zhang
![Page 2: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/2.jpg)
• Anthropogenic global warming causes “robust” changes in the global hydrological cycle
• “Robust” changes (in this context) means changes are directly related to global mean temperature change*
• QuesFon: Are hydrological cycle changes in the paleoclimate (last 22ky) similarly “robust?” – Answer: Only sort of. We’ll examine why this is.
Outline:
*e.g. Held & Soden 2006
![Page 3: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/3.jpg)
“Robust” changes in the global hydrological cycle due to anthropogenic
global warming
Atmospheric radiative cooling constraints (surface energy
balance)
Held & Soden, 2006
![Page 4: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/4.jpg)
“Robust” rainfall changes: wet get weTer and the dry get drier
S
Fig. 6b From Held & Soden (2006) Latitude
SRES A1B scenario
![Page 5: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/5.jpg)
Zhengyu Liu (UW-Madison), B. Otto-Blienser (NCAR)
Realistic Forcing
Insolation GHGs Meltwater Icesheet
Model: NCAR-CCSM3 – fully coupled ocean-atmosphere GCM
Liu et al., 2009, Science
Greenland Temperature Obs (grey), Model (red)
![Page 6: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/6.jpg)
Unexpected TRACE paleoclimate results: q (global water vapor) versus surface T
Surface Temperature (C)
“surface-CC scaling:” 6.7%
shows 4.2 % q increase per unit T change.
At apparent odds with: Consistent with
Boos 2012 results
![Page 7: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/7.jpg)
Unexpected TRACE paleoclimate results: q (global water vapor) versus surface T
Surface Temperature (C)
“surface-CC scaling:” 6.7%
shows 4.2 % q increase per unit T change.
At apparent odds with:
Slope increases during anthropogenic warming era to 7.2 %
![Page 8: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/8.jpg)
Possible explanaFons for 4.2% water vapor increase per unit K warming
• Rela%ve humidity is not constant over climate-‐change %me scales?
• Clausius-‐Clapeyron rela%onship non-‐lineari%es?
• Tropical upper troposphere warms more than surface at warmer temperatures?
• Rapid CO2-‐induced warming affects global water vapor differently than slow CO2-‐induced warming?
![Page 9: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/9.jpg)
56%
57%
8 C
12 C Total water vapor in atmosphere
Total water vapor atmosphere would have if saturated
Blue shows:
Column relative humidity changes small
Rela%ve humidity is not constant over climate-‐change %me scales?
![Page 10: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/10.jpg)
Try changing CO2 rapidly by running branch simulaFons where CO2 doubles instantaneously
Time (ka BP)
CO2 doubling
CO2 doubling
CO2 doubling
Anthro- pogenic
![Page 11: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/11.jpg)
Try changing CO2 rapidly by running branch simulaFons where CO2 doubles instantaneously
CO2 doubling
CO2 doubling
CO2 doubling
Anthro- pogenic
‘s = “Rapid” warming
Time (ka BP)
![Page 12: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/12.jpg)
Rapid CO2-‐induced warming affects global water vapor differently than slower warming
Surface Temperature (C)
“surface-CC scaling:” 6.7%
Rapid warming d(lnq)/dT greater than slow warming d(lnq)/dT
![Page 13: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/13.jpg)
Slow CO2 increases symmetric warming
Rapid CO2 increases N.H. warms more
dominates response
response.
“Slow”
“Rapid”
Latitude
Figure shows amount of surface warming by latitude normalized for a global surface T increase of 1K
![Page 14: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/14.jpg)
S. Ocean thermal inertia
Slow CO2 increases symmetric warming
Rapid CO2 increases N.H. warms more
dominates response
response.
“Slow”
“Rapid”
Latitude
Figure shows amount of surface warming by latitude normalized for a global surface T increase of 1K
![Page 15: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/15.jpg)
Slow CO2 increases symmetric warming
Rapid CO2 increases N.H. warms more
dominates response
response.
“Slow”
“Rapid”
Latitude
More tropical warming per global T increase
Figure shows amount of warming by latitude normalized for a global T increase of 1K Figure shows amount of surface warming by latitude normalized for a global surface T increase of 1K
![Page 16: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/16.jpg)
Consider a hypotheFcal 3-‐box model of warming paTerns
• Assume most water vapor is in tropics due to warmest temperatures there – Water vapor increases exponenFally with T
• Assume warming paTern in 3 equal-‐area boxes:
• “Slow” has less global d(lnq)/dT than “rapid” case
S. H. N. H. Tropics
Rapid
Slow
0
1 0 1
1 1
![Page 17: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/17.jpg)
Real 3-‐box model numbers, where each box has equal area, support
interpretaFon • For 1 degree global temperature change:
S. H. N. H. Tropics
Rapid
Slow
0.75
1.4 0.42 1.2
0.71 1.5
![Page 18: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/18.jpg)
Why does global water vapor increase more (% per K global T change) in response to rapid (anthropogenic-‐like) CO2 change?
• Most water vapor is in the tropics -‐-‐> amount of tropical warming strongly influences global water vapor change
• Tropics warm more (per unit global T change) if warming is concentrated in one hemisphere
• Therefore, one-‐hemisphere warming -‐-‐> larger global water vapor increase (%) per K global warming
![Page 19: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/19.jpg)
€
q = q0eαδT
Global water vapor
Function of initial water vapor & delta T
Local mixing ratio increases at
Clausius-Clapeyron
AlternaFve predicFon of global water vapor increases:
€
δT = δT +δT ' = Mean surface T change + perturbation T change
Correction due to inhomogeneous temperature increases
![Page 20: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/20.jpg)
Slow
Rapid
4.3 %
6.2 % 6.6 %
6.7%
-0.3 %
-2.6 %
AlternaFve theoreFcal predicFon of water vapor increases matches
simulated increases
![Page 21: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/21.jpg)
TRACE Paleoclimate results: Global precipitaFon vs. surface T
“Slow” and “Rapid” cases behave similarly
P increases at 1.9% per unit surface T warming
Global Temperature (Celsius)
![Page 22: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/22.jpg)
TRACE paleoclimate warming: Wet [mostly] get weTer & dry [mostly] get drier
Latitude
For a 1 degree global surface T change:
“thermodynamic” scaling
Mean Δ(P-E) and +/- a standard deviation
![Page 23: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/23.jpg)
Rapid CO2 doubling: Wet [mostly] get weTer & dry [mostly] get drier
Latitude
For a 1 degree global surface T change:
“thermodynamic” scaling
Mean Δ(P-E) and +/- range (for CO2 doubling cases, anthropogenic)
![Page 24: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/24.jpg)
“Rapid” & “Slow” T changes lead to somewhat different precipitaFon changes
Latitude
For a 1 degree global surface T change:
Rapid Slow Thermodynamic
scaling (dashed lines) is similar for rapid and slow changes.
Modeled changes significantly different
![Page 25: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/25.jpg)
Hydrological cycle changes in TRACE paleoclimate (last 22ky) compared to rapid (anthropogenic-‐like) CO2-‐induced changes: • Global water vapor increases less (per unit warming) in TRACE paleoclimate – Longer Fmescale of S. Ocean adjustment different spaFal paTern of warming for rapid vs. slow warming
– most q in tropics (Clausius-‐Clapeyron non-‐linearity) global dlnq/dT dependent on tropical warming amount
• Global mean precipitaFon changes comparable
• Zonal precipitaFon paTern changes somewhat different due to circulaFon paTern changes
![Page 26: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/26.jpg)
“Local” d(ln q)/dT by la%tude and height
• Is a range of dq/dT (% change water vapor per unit warming)
“Rapid” warming
“Slow” warming
Latitude
![Page 27: Global&hydrological&cycle&response& …kuang/LarissaBack.pdfGlobal&hydrological&cycle&response& to&rapid&and&slow&global&warming&& LarissaBack,& Kuniaki&Inoue,&Karen&Russ,& ZhengyuLiu](https://reader034.vdocument.in/reader034/viewer/2022043019/5f3bc5dab2029750570b0698/html5/thumbnails/27.jpg)
“Local” temperature change paHerns:
• Put Karen’s figure in showing T change here
• Or show my figure from my idealized model…