1. 지구온난화에 의한 북서태평양에서의 상세 해수면 상승 예측(I) - 해수팽창을 고려한 지역해양순환모형의 규모축소 모의 실험 -
서울대학교 세미나
지구온난화에 의한 북서태평양에서의 상세 해수면 상승 예측(I) - 해수팽창을 고려한 지역해양순환모형의 규모축소 모의 실험 -
김 동 훈 연세대학교
2012/11/13

2. The impact of global warming?
Basic Knowledge
The impact of global warming?
rising ocean temp. < rising land temp. → large changing in seasonal monsoon
rising temp. in the Arctic
(decreasing Albedo in the Arctic area)
→ increasing the heat capacity of the Arctic Ocean
→ reducing the temperature gradient by latitude
→ changing major ocean currents

3. To project regional sea level rise due to global warming
Coupled Model (Atmosphere - Ocean - Land Surface - Sea Ice)
Regional simulations in high resolution
Parallel optimazation for long-term simulations
Compressible or Mass conservation Ocean Models : thermal expansion, melting land ice, runoff, …
Global Warming
water forcing
source
free surface
rigid-lid
steric
dynamics
Dynamic Height :

4. ∆SST ∆SSH A Previous Study
CO2 Doubling (after 70 years) in the Northwestern Pacific Ocean
SST : 1.5℃ ↑
SSH : 10cm ↑ (steric effect)
∆SST
∆SSH
Kim, D.-H., 1999: Sea Level Change due to Global Warming in the Northwestern Pacific Ocean
Dynamic Height :

5. CM2.1 vs. ReMOM Model Configuration (ReMOM, Regional MOM4.1)
Regional MOM4.1 : B-grid hydrostatic nonBoussinesq ocean model with pressure vertical coordinate
Northwestern Pacific (115°E~150°E, 20°N~52°N) : 0.2° x 0.2° x 34layers
I.C. & B.C. : IPCC(CM2.1,MIROC3.2H,HADCM3) SRES A1B & B1 (100yr simulation)
Sea Surface : Wind Stress, SST, SSS (1day restoring)
Lateral B.C. : T, S, U, V (sponge boundary = 1day~30day)
Sponge B.C.
1day ~ 30 day
CM vs. ReMOM
Coarse Resolution Depth in CM2.1(IPCC) (Grid Spacing: 1°)
Fine Resolution Depth in ReMOM (Grid Spacing: 0.2°)

6. Total Calculations : 900 years
Model Projection (ReMOM, Regional MOM4.1)
CM2.1 I.C. & B.C.
SRES A1B
SRES B1
2001
2100
Control Run using
mean states of 1991 ~ 2000
100 yrs
Scenario Runs (100 yrs)
MIROC3.2H I.C. & B.C.
SRES A1B
SRES B1
2001
2100
Control Run using
mean states of 1991 ~ 2000
100 yrs
Scenario Runs (100 yrs)
Average
Difference
(= 2090s – 1990s)
HADCM3 I.C. & B.C.
SRES A1B
SRES B1
2001
2100
Control Run using
mean states of 1991 ~ 2000
100 yrs
Scenario Runs (100 yrs)
Total Calculations : 900 years

7. SRES A1B SRES B1 3℃ SST 2℃ SST 35cm SSH 25cm SSH
SST & SSH in the Northwestern Pacific Ocean (NWPO)
SRES A1B SRES B1 3℃
SST 2℃
SST
MIROC3.2H
HADCM3
CM2.1
35cm
SSH
MIROC3.2H
25cm
SSH
HADCM3
CM2.1

8. Compare with CM2.1 : SST & SSH in the NWPO (SRES A1B)
CM vs ReMOMw/ CM2.1 3℃
CM2.1: SST 3℃
ReMOM: SST
12cm
CM2.1: SSH
30cm
ReMOM: SSH

9. CM2.1 vs. ReMOMw/ CM2.1 ∆SST ∆SST ∆UV ∆UV
Compare with CM2.1 : ∆SST & ∆SurfaceCurrents (SRES A1B)
CM vs ReMOMw/ CM2.1
∆SST
∆SST
∆UV
∆UV

10. Compare with CM2.1 : Steric Sea Level Changes (SRES A1B)
CM vs ReMOMw/ CM2.1

11. SRES A1B SRES B1 ∆SST ∆SST ∆UVsurface ∆UVsurface
Spatial Distribution of ∆SST & ∆SurfaceCurrents
SRES A1B SRES B1
∆SST
∆SST
Northward expansion of the Kuroshio separation area
Transport increase of the Tsushima warm current
∆UVsurface
∆UVsurface

12. SRES A1B SRES B1 ∆SSH ∆SSH steric ∆SSH ∆SSH nonsteric
Sea Level Changes(Rise)
SRES A1B SRES B1
∆SSH
steric
∆SSH steric
∆SSH
nonsteric
∆SSH nonsteric

13. => Pressure Gradients :
(non-)Boussinesq Ocean Climate Model
In ocean climate modelling, it has been traditional to exploit the large degree to which the ocean fluid is incompressible, in which case the volume of fluid parcels is taken as constant. These fluids are said to satisfy Boussinesq kinematics.
Boussinesq Approximation : ignore variations in density
=> Pressure Gradients :
=> Continuity Eq. :
Primitive Eq. : Mass Conservation Eq.(M) → Volume Conservation Eq.(V) Boussinesq fluids
Boussinesq fluids : heating → decreasing the density
By volume conservation, decreasing the density reduces the mass and bottom pressure while the sea level remains unchanged.
non-Boussinesq fluids : heating → decreasing the density
By mass conservation, decreasing the density increases the volume and sea level, while the bottom pressure remains unchanged.

14. Non-Boussinesq Ocean Climate Model
Primitive Eq. : Mass Conservation Eq.(M) → Volume Conservation Eq.(V) Boussinesq fluids
source
water forcing
dynamics
steric
Pressure based vertical coordinates : It can be diagnosed in a straightforward manner.
Depth based vertical coordinates :

15. ∆SSH ∆SSH Steric & nonSteric Sea Level Changes(Rise) (SRES A1B) 35cm
Ref.
Sea Level Changes in CM2.1
∆SSH
steric
∆SSH
nonsteric
<--- Sea Level Change after 100 year ---->
35cm
East Sea & Pacific : governed by steric effect
Yellow Sea : governed by non-steric effect

16. 쿠로시오수의 대륙붕 유입과 대만해류
대마난류(TWC)의 두개의 기원 - 쿠로시오의 대륙붕 유입(OIK) - 대만해류(TSC, 쿠로시오수와 무관)
대륙붕 유입(OIK) : PK + PT - 해수면 차이에 의해 유입 - PK는 관측으로 입증되었으나 PT는 뚜렷히 입증된 바 없음
대마난류(TWC)의 수송량은 - TSC와 OIK가 서로 경쟁적으로 기여

17. Transport changes due to Global Warming
ReMOMw/ CM2.1

18. 대마난류 대만난류 쿠로시오 해류 w/ CM2.1 w/ HadCM3 w/ MIROC3.2h
Transport changes due to Global Warming
대마난류
대만난류
쿠로시오 해류
w/ CM2.1
w/ HadCM3
w/ MIROC3.2h 증가 감소

19. Transport changes due to Global Warming

20. Summary
We simulated regional sea level as a prognostic variable using non-Boussinesq Ocean Model
For the SRES A1B and B1, ReMOM predicts that the ensemble averaged sea levels rise 35 cm and cm, respectively, in the Northwestern Pacific Ocean.
Large-scale warmings are found in the middle of East Sea and Kuroshio separation area.
The sea level rise in East Sea is mainly governed by steric effect, while the nonsteric effect mainly contribute on sea level rise in Yellow Sea.
Transport of Kuroshio/Tsushima Current has decreased/increased, respectively.

21. Thank you…
Kim, Dong-Hoon (

22. Spatial Distribution of Surface Currents and its Difference
CM vs ReMOMw/ CM2.1
Surface Currents
Surface Currents
Northward expansion of the Kuroshio separation area
Transport increase of the Tsushima warm current
∆UV
∆UV

23. ∆SSS ∆UV Compare to CM2.1 : non-steric .vs. steric (SRES A1B) ∆SSH
Runoff change after 100 years
SSS change after 100 years
∆SSS
∆UV
∆SSH
∆runoff