Tropical Cyclones and Climate Change
Results from HiGEM
Ray BellSupervisors – Prof. Pier Luigi Vidale, Dr. Kevin
Hodges and Dr. Jane Strachan
Trop goup – 10th Oct
• Will there be a change in TC activity (location, intensity, frequency, lifetime, structure) with climate change?
• How does this change depend on resolution?
• How well are the governing mechanisms represented in climate models and how does resolution affect their representation?
• What is the role of teleconnections - Possible ENSO changes on NAtl TC activity?
• [What is the role of coupling with the ocean?]
PhD questions
• Explaining the change of TC activity– Change in parameters relevant to TCs: SST, vws, RH, -ω
• Investigating the ENSO teleconnections on TCs (and possible ENSO change)
- Change in NINO3.4 SSTs - El Niño composites vs. La Niña composites
Current work
Tighter filter on storms.
• Warm core testing between individual levels (still applying dec. Vor. With height)
• Test for cold core at lower levels and warm core aloft• Removes monsoon type depressions
New warm core level TRACKing
Change in track densities with increased CO2
Change in TC frequency (%)
TC/yr NH ATL WPAC EPAC NIND% changeFor ctrl
att att att att att
30yr 2xCO2
-5.6 -0.7 -24.8 -22 -8.7 -6.6 -3.2 7.7 14.6 38.630yr4xCO2 -22.2 -13.6 -47.5 -41.7 -22.0 -19.25 -40.73 -25.39 -2.76 15.92
CPAC
-1.67 -8.57
38.46 40.79
Regional change of 850hPa wspeed
Large scale tropical change
regional scale tropical change
Change in SST
Zhao et al (2009)
Change in vws
Vecchi et al (2007)
Change in RH700
Vecchi et al (2007)
Change in –ω500
Change in ppt
ENSO telleconnections on HiGEM TCs
Bengtsson et al (2006)
NINO3.4 SST DJF > 1 or <1, year containing D
Future work• More analysis explaining the TC change – change in Walker
and Hadley plots
• TCs in different resolutions and climate change simulations
• Changes in SH
• ENSO influence on NATL activity - compare IBTrACS and re-analysis to HiGEM present day simulation.
2 types of ENSO in HiGEM
Kug and Ham (2011)• Investigate change in TC activity with the 2 types of El Nino.
• Investigate the change in types of ENSO in HiGEM inc. CO2 and the TC relation
HiGEM CTRL TC frequency
CPAC5x30 years ctrl
4.3(1-4.4)
3(0-4.2)
TC/yr NH ATL WPAC EPAC NINDatt att att att att
5x30 years ctrl
67.3(63.9-71)
49.8(47.1-51.3)
4(5.1-2)
3(1-4.1)
32.6(28.9-41)
28.6(26.4-34)
19.4(17.3-22)
10.4(9.5-10.6)
4.6(3-5.6)
3.1(2.3-3.7)
Obs (83-07)
63 12.3 28.3 16.6 5.8
9.010.811.412.114.8
Atl Additional obs are 1851-2010, 1944-2010, 1966-2010, 1981-2010, 1995-2010From Blake (2010)
Change in structure100 most intense TCs at most intense
4xCO2
Earth relative windsBelow 35oNNH
2xCO2
10o radius850hPa
Avg 30 yr ctrl
