Ryan N. Maue's Seasonal Tropical Cyclone Activity Update
Northern Hemisphere 2009 Year in Review --> Final Statistics
North Atlantic Hurricane Season ends -- > Houston Chronicle
November 30, 2009: With the official end of the 2009 North Atlantic hurricane season, it is time to put the season in perspective and compare to the past 70-seasons. In terms of the Accumulated Cyclone Energy index [ACE], 2009 tallied ~52 ACE points which is less than half of normal. Here is a listing of the past 70-years of ACE values for the North Atlantic Listing . 2009 was the quietest year since 1997 (ACE= 41) and the 16th slowest since 1940. Interestingly, 2009 saw 1/5th of the activity of 2005, the most active ACE season on record. 3 storms out of the total of 9 accounted for 85% of the total ACE (Bill, Fred, and Ida). These 3 storms were the only hurricanes out of the total 9 tropical storms.
Newsbusters.org Piece on Al Gore's New Book Photoshopping Hurricanes -- Ryan Maue's simple bookstore research -- Link
Denver Examiner: Hurricanes and Tornadoes at below normal levels in 2009 -- Link
Houston Chronicle Article on Tropical Storms and Global Warming -- Link
North Atlantic Hurricane Season slowest since 1997 -- Figure
Global and Northern Hemisphere Tropical Cyclone Activity remains near 30-year historical lows
-- three years in a row now of considerably below-average activity globally. -- Figure
Consequence of the transition from La Nina to El Nino during the past year
The best of 2009: Hurricane Bill, Hurricane Fred, Hurricane Rick, Super Typhoon Melor, Typhoon Parma
Important Links
The Raw Data -- Accumulated Cyclone Energy (ACE) valid February 09, 2010 12Z
The current ACE represents the tropical cyclone activity from January 1, 2009 until the date indicated. This is readily compared to the YEARLY value which is the previous 30-year average from Jan 1 - Dec 31 or the calendar year. The values for 2008 and 2007 are included for reference as well. There is considerable year-to-year variability across the basins, of which understanding motivates the updating and maintainance of this site.
| BASIN | 2009-10 CURRENT | 30-YR AVG | 2008 | 2007 | 2006 |
| N Hemisphere | 461 | 563 | 431 | 386 | 554 |
| S Hemisphere | 95 | 204 | 190 | 176 | 160 |
Maximum Wind Speed & ACE per storm
Southern Indian OceanAnja (105 ACE = 12.4925)
Bongani (40 ACE = 1.29)
Cleo (115 ACE = 10.47)
Mick (70 ACE = 3.215)
David (55 ACE = 4.6785)
Laurence (130 ACE = 17.2325)
Edzani (140 ACE = 21.21)
Magda (65 ACE = 2.8225)
Olga (50 ACE = 2.375)
Nisha (50 ACE = 2.1575)
Eleven (35 ACE = 0.8575)
Oli (115 ACE = 13.755)
Fami (40 ACE = 0.2825)
Pat (65* ACE = 2.285*)
Gelane, Hubert, Imani, Joel, Kanja
Lunda, Mohono, Nigel, Olympe, Pamela
Quentin, Rahim, Savana, Themba, Uyapo
Viviane, Walter, Xangy, Yemurai, Zanele
|
24-Month Running Sums of ACE from 1959-2009 |
2008-2009 Southern Hemisphere Tropical Cyclones
Asma (55 ACE = 2.885)
Anika (60 ACE = 1.76)
Bernard (40 ACE = 0.565)
Cinda (55 ACE = 2.81)
Billy (105 ACE = 13.44)
Dongo (55 ACE = 2.08)
Charlotte (35 ACE = 0.3675)
Eric (35 ACE = 1.1025)
Fanele (100 ACE = 5.36)
Dominic (50 ACE = 0.735)
Hettie (35 ACE = 0.245)
Ellie (40 ACE = 0.6875)
Gael (120 ACE = 18.5125)
Freddy (55 ACE = 2.1775)
Innis (40 ACE = 0.65)
Hina (65 ACE = 2.5475)
Gabrielle (35 ACE = 0.735)
Hamish (130 ACE = 21.5)
19S (35 ACE = 0.1225)
Joni (55 ACE = 2.775)
Ken (70 ACE = 2.7)
Ilsa (105 ACE = 11.6575)
Jasper (45 ACE = 0.97)
Izilda (65 ACE = 2.5225)
Lin (50 ACE = 1.145)
Jade (65 ACE = 4.9675)
Kirrily (40 ACE = 0.8475)
Southern Hemisphere ACE = 106 for 2008-2009
Total Tropical Storms + 27
Total Cyclones (64 kts+) 9
Four cyclones account for > 60% of the seasonal ACE
Notes on Data and Methods and Citation and Funding Sources
This page can be cited as ongoing research related to my dissertation and publications resulting from it.Maue, R. N., 2009: Northern Hemisphere Tropical Cyclone Activity. Geophys. Res. Lett., 36, L05805, doi:10.1029/2008GL035946. Abstract Funding is provided in part by a variety of sources. COAPS is funded by NOAA and Ryan Maue received a NASA Earth Systems Fellowship during the years of 2006-2009. Additional funding has been provided to my major professor Mark A. Bourassa by NASA and other agencies in order to support publications, travel, and research. The author of this website is very appreciative of $upport.
Climatology is based upon the past 30-years of tropical cyclone activity (1979-2008). Historical tropical cyclone tracks are obtained from two sources: National Hurricane Center (NHC) for Eastern Pacific and North Atlantic basins and the Joint Typhoon Warning Center (JTWC) for the Western Pacific, Northern and Southern Indian Oceans, and the South Pacific including the Australian region. Best-track data when cyclones are in an extratropical phase are disregarded, where this is included in the datasets. While there are several other sources of best-track hurricane data for the different basins around the globe, it is not apparent which source of tropical cyclone intensity estimates is the best, most correct, or most consistent throughout the past 30-years. Until that research is completed, it is my policy to use NHC and JTWC data for global tropical cyclone data. I will attempt to use RSMC (Tokyo) and the IBTrACS merged database for comparison purposes in the near future. (Update: June 24, after calculating ACE using the IBTrACS mean intensity, which can include from 1-4 different reporting centers, the differences are negligible. Therefore, it is appropriate to use the NHC+JTWC for global studies on yearly time scales. Naturally differences crop up when examining storm by storm and observation by observation differences. This is a disasterous complication when doing count/frequency studies such as Webster et al. (2005) but is mitigated with accumulated cyclone statistical studies (i.e. Emanuel 2005; Maue 2009).

