Tropical forcing for the interannual variability of the subtropical high
description
Transcript of Tropical forcing for the interannual variability of the subtropical high
![Page 1: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/1.jpg)
Tropical forcing for the interannual variability of the subtropical high
Pei-Hsuan Chung and Chung-Hsiung SuiDepartment of Atmospheric Sciences, National Central University,Jhong Li, Taiwan
Tim LiDepartment of Meteorology and IPRC, University of Hawaii, Honolulu, Hawaii, USA
![Page 2: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/2.jpg)
Sui, C. -H., P. -H. Chung, and T. Li, 2007: Interannual and interdecadal variability of the summertime western North Pacific subtropical high. Geophys. Res. Lett., 34, 253 L11701, doi:10.1029/2006GL029204.
Time SeriesWNPSHI = H500 anom (120-140E, 10-30N)
OBS AnalysisOBS Analysis
![Page 3: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/3.jpg)
Power Spectrum of WNPSH I ndex
0
1
2
3
4
5
6
123456789
Periods (Years)
Pow
er
Den
sit
y
Density
95% TEST
2.5 Yrs
3.6 Yrs
Power Spectrum of WNPSH Index
Time Filtering: 2-3-yr and 3-5-yr WNPSH Index
![Page 4: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/4.jpg)
Shading: vertical p-velocity (Pa/s) Vectors: significant W500 (m/s)Color contours: OLR (W/m2) Black contour: H500 (unit: m)
![Page 5: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/5.jpg)
Shading: vertical p-velocity (Pa/s) Vectors: significant W500 (m/s)Color contours: OLR (W/m2) Black contour: H500 (unit: m)
![Page 6: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/6.jpg)
What are the key SSTA forcing dominated in 2-3-yr and 3-5-yr oscillations of the westwarding WNP subtropical
high?
Model Simulation
![Page 7: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/7.jpg)
QTCM Model QTCM : Quasi-equilibrium Tropical Circulation
Model with a single vertical structure of temperature and moisture for deep convection
Intermediate complexity atmospheric model The model formulation makes use of the
constraints placed on the flow by deep convection, as represented by quasi-equilibrium (QE) convective parameterizations
![Page 8: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/8.jpg)
Experiment design
Control SST Run 1958-2005 monthly mean SST to run 50
years simulations and use the middle 30 years results
Prescribe SSTA Run MJJA : Add (High-Low) composite SSTA
in some key regions JFMA and SOND : Climate SST as CTRL Prescribe SSTA Run - Control SSTA Run
![Page 9: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/9.jpg)
![Page 10: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/10.jpg)
2-3-yr oscillation
MJJA SSTA
(High-Low) Comp
CEP RunMC Run
![Page 11: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/11.jpg)
MC Run
CEP Run
Total Run
![Page 12: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/12.jpg)
WNP Run
IO+EP Run
3-5-yr oscillation
MJJA SSTA
(High-Low) Comp
![Page 13: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/13.jpg)
WNP Run
EP+IO Run
Total Run
![Page 14: Tropical forcing for the interannual variability of the subtropical high](https://reader036.fdocuments.net/reader036/viewer/2022062321/56813fe8550346895daad861/html5/thumbnails/14.jpg)
Discussion
2-3-yr oscillation ~ Total run 3-5-yr oscillation ~ WNP run
(local cold SSTA)
Using “heating” instead of SSTA GCM models