Statistical Downscaling
description
Transcript of Statistical Downscaling
Bruyere Statistical Downscaling RPSEA 0310
Statistical Downscaling
Cindy Bruyère
NCAR Earth System LaboratoryNational Center for Atmospheric Research
NCAR is Sponsored by NSF and this work is partially supported by the Willis Research Network and the Research Program to Secure Energy for
America
Bruyere Statistical Downscaling RPSEA 0310
Statistical Downscaling
• Look at at Genesis Potential– Mainly focusing on NNRP– CCSM (A2 and A1B scenarios) – NRCM
Bruyere Statistical Downscaling RPSEA 0310
Genesis Potential IndexGP = 105η RH850
30⎛⎝⎜
⎞⎠⎟
3 Vpot70
⎛⎝⎜
⎞⎠⎟
3
1 + 0.1Vshear( )−2
η = absolute vorticity
Vpot = potential intensity
Vshear = shear between 850hPa and 200hPa
Emanuel and Nolan (2004)
Camargo (2007)
Bruyere Statistical Downscaling RPSEA 0310
NA Basin
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
J F M A M J J A S O N D
Number of storms
0
0.2
0.4
0.6
0.8
1
1.2
1.4
GP
cor=0.91
No Storms
Annual Max GP
GP in NNRP Model
Bruyere Statistical Downscaling RPSEA 0310
GP distribution in NNRP
Bruyere Statistical Downscaling RPSEA 0310
w-dev e-dev
dev
gulfNA basin
Basin Gulf Dev East Dev West Dev
Dev + All
Storms
Storms in Gulf
Dev + Storms in Gulf
Max (55-05) .35 .22 .60 .44 .35 .61 .23 .44 Max (80-05) .55 .11 .71 .64 .55 .75 .23 .49 ASO (55-05) .41 .35 .61 .43 .44 .63 .28 .51 ASO (80-05) .60 .24 .74 .63 .66 .79 .27 .58
GP - A Different Approach
Bruyere Statistical Downscaling RPSEA 0310
GP from CCSM (A2)
GP in MDR - NNRP vs CCSM
Bruyere Statistical Downscaling RPSEA 0310
Meridional Avg of GP (15-60W)NNRP
Bruyere Statistical Downscaling RPSEA 0310
CCSM - A2
Meridional Avg of GP (15-60W)NNRP
Bruyere Statistical Downscaling RPSEA 0310
Bruyere Statistical Downscaling RPSEA 0310
Conclusions• Looking at basin wide annual max or ASO average
GP has little value• GP (annual max and ASO average) in development
region is a better measure of storm development in basin
• GP in Gulf has a poor correlation between storms that develop or move through the Gulf area
• GP in CCSM and NRCM runs indicate an increase in GP in the lower latitudes
• More work is needed to develop a better index in the Gulf