A picture's worth a thousand words, so here's the summary, including late-breaking
Tropical Storm Zeta:
Some say it's just cycles. But I don't see simple repeating cycles in these data. I see escalating cycles. If there's some larger cycles (and there could be), their scale is too long to be visible in the available data. Tropical Storm Zeta info follows year-end summary & thoughts for the future.
It's useful to compare the storm data with the Atlantic Multidecadal Oscillation. That's the one that leads to predictions high intensity Atlantic hurricane storm seasons for at least the next few years:
(for full sized image of above - about 1/3 wider, click here.) These two figures track pretty closely, except the 1970s dip in AMO doesn't have so marked a drop in storm activity as does that of the 1910s.
Sea surface temperatures from Science:
From the same article:
In addition to interannual and multidecadal variability, there is a nonlinear upward trend in SSTs over the 20th century. This trend is most pronounced in the past 35 years in the extratropical North Atlantic (see the first figure). It is associated with global warming and has been attributed to human activity. In the tropical North Atlantic--the region of most relevance to hurricane formation--multidecadal variability dominates SSTs (see the figure above), but the 1995-2004 decadal average is nonetheless the highest on record by >0.1°C. Hence, although the warming in the tropical North Atlantic is not as pronounced, it is probably related to that in the extratropical North Atlantic.
That's fancy talk for "escalating" cycles, for trending upwards. If you're inclined towards data geekiness, I recommend reading the whole article, which discusses statistics and data analysis in greater detail. NOAA has an FAQ on Atlantic Multidecadal Oscillation (AMO).
From Science, 1 July 2005, by Richard A. Kerr:
The ocean conveyor "is an important source of climate variability," says meteorologist James Hurrell of the National Center for Atmospheric Research in Boulder, Colorado. "There's increasing evidence of the important role oceans have played in climate change." And there are growing signs that the conveyor may well begin to slow on its own within a decade or two, temporarily cooling the Atlantic and possibly reversing many recent climate effects. Greenhouse warming will prevail globally in both the short and long terms, but sorting out just what the coming decades of climate change will be like in your neighborhood could be a daunting challenge.
...
Judging by the 1400-year simulation's AMO, Knight and colleagues predict that the conveyor will begin to slow within a decade or so. Subsequent slowing would offset--although only temporarily--a "fairly small fraction" of the greenhouse warming expected in the Northern Hemisphere in the next 30 years. Likewise, Sutton and Hodson predict more drought-prone summers in the central United States in the next few decades.
As I write this, TV news is reporting fires in Oklahoma and Texas, and worst drought since the 1950s in the Dust Bowl area. There's almost no snow in the mountains here in New Mexico - the winter storms are all passing to the north, causing flooding in northern California. Looking at the AMO figure again, we see peaks for the 1880s, 1930s, 1950s and the present. Corellates closely with major drought periods in the southwest & Dust Bowl areas. Perhaps the main rainfall that will be seen in Texas in the next few years will be from Rita-style storms? Not a pretty picture emerging. For more on associated suite of weather conditions, see this from NOAA news.
The article continues:
But don't bet on any of this just yet. The AMO "is not as regular as clockwork," says Knight; it's quasi-periodic, not strictly periodic. And no one knows what effect the strengthening greenhouse might have on the AMO, adds Sutton. Most helpful would be an understanding of the AMO's ultimate pacemaker. In the Hadley Centre model, report modelers Michael Vellinga and Peili Wu of the Hadley Centre in Exeter in the December Journal of Climate, the pulsations of the conveyor are timed by the slow wheeling of water around the North Atlantic. It takes about 50 years for fresher-than-normal water created in the tropics by the strengthened conveyor to reach the far north. There, the fresher waters, being less dense, are less inclined to sink and slide back south. The sinking--and therefore the conveyor--slows down, cooling the North Atlantic and reversing the cycle.
Incidentally, warm cycles tend to correlate with more active Atlantic storm seasons, so the experts say. Looking at the AMO figure above, and adding that 5 of the top ten active hurricane seasons since 1851 have occurred since 2000 (with 1995 also in the top ten), there's ample reason for concern on that score as well.
On that note, I'll wish everyone a Happy New Year. Or as Olbermann, quoting Murrow, says, "Good night, and Good Luck". We're gonna need it. That, and serious efforts to take the Global Warming bull by the horns.
2005 ATLANTIC HURRICANE SEASON
Officially, Atlantic Hurricane Season goes from June 1 through November 30. Most, but not all, storms occur during that window. For example, Hurricane Alice (category 1) made landfall at St. Kitts on January 2, 1955. In fact, there have been Atlantic tropical storms and hurricanes recorded during every month of the year. Here's a bit of data on the non-hurricane season months since 1851 (recorded by the month the storm first formed):
- Dec/7 2005, 2003, 1975, 1954, 1953, 1887(2)
- Jan/2 1978, 1894
- Feb/1 1952
- Mar/1 1908
- Apr/1 2003
- May/18 1997, 1981, 1976, 1972, 1970, 1959, 1954, 1951, 1948, 1940, 1934, 1933, 1932, 1890, 1889, 1887(2), 1865
There's several ways this has been a record breaking hurricane season.
- 27 Total number of named storms
- 14 Total number of hurricanes
- 7 Total number of major hurricanes (category 3+)
- 3 Total number of Category 5 hurricanes
- 883 Lowest recorded barometric pressure (Wilma)
- 6 Total number of retired names: Dennis, Emily, Katrina, Rita, Stan & Wilma
- First ever landfalls in Spain & in Morocco
Here's Tropical Storm Zeta:
Not really something to worry about, but something to marvel at. As always, further discussion can be found at Jeff Masters' excellent Weather Underground site, with informative discussion. For example, did you know that Hurricane Katrina, in retrospect was downgraded to a Category 3 storm at landfall? For the official stuff, NOAA's National Hurricane Center is the place to go.
Here's a parting shot of Tropical Storm Zeta:
NOTE: I prepared this earlier today but a couple of other diaries appeared first about Tropical Storm Zeta. Those diaries are here and here, and have some good information throughout the comments. This one has a broader summary, and additional information. Cross-posted at EPluribusMedia.
2004 was a pretty rough hurricane year. At the end, officials said that 2004 was exceptional year, and 2005 was expected to be less severe by comparison. We now know that prediction was pretty far off the mark. So, now, take the poll: