Wednesday, November 03, 2010

Remember the Bermuda high?...

As we rip bone-dry fields and neighbors pause to debate applying NH3, the faint memory of drought and the mysterious "Bermuda high" came tumbling back into my thoughts.  It could be worrying about our well here at house helped trigger this speculation.

Anyhoo, this may be just another aspect of climate change from global warming that was predicted by ag climatologists.
A new study by a Duke University-led team of climate scientists suggests that global warming is the main cause of a significant intensification in the North Atlantic Subtropical High (NASH) that in recent decades has more than doubled the frequency of abnormally wet or dry summer weather in the southeastern United States. 

The NASH, commonly referred to as the Bermuda High, is an area of high pressure that forms each summer near Bermuda, where its powerful surface center helps steer Atlantic hurricanes and plays a major role in shaping weather in the eastern United States, Western Europe and northwestern Africa.
By analyzing six decades of U.S. and European weather and climate data, the Duke-led team found that the center of the NASH intensified by 0.9 geopotential meters a decade on average from 1948 to 2007.  (Geopotential meters are used to measure how high above sea level a pressure system extends; the greater the height, the greater the intensity.)
The team’s analysis found that as the NASH intensified, its area enlarged, bringing the high’s weather-making western ridge closer to the continental United States by 1.22 longitudinal degrees a decade.
“This is not a natural variation like El Nino,” says lead author Wenhong Li, assistant professor of earth and ocean sciences at Duke University’s Nicholas School of the Environment.   “We thoroughly investigated possible natural causes, including the Atlantic Multivariate Oscillation (AMO) and Pacific Decadal Oscillation (PDO), which may affect highs, but found no links.
“Our analysis strongly suggests that the changes in the NASH are mainly due to anthropogenic warming,” she says. [More]
It is back-to-back episodes of heavy rain and drought that has me most concerned about how to prepare our farm. To be sure we have been tiling like crazy (BTW - plastic tile is hard to get around here), but the on-off nature of rain the last 3 years is growing tiresome.

Frankly, I think it will continue to be a massive marketing headache for seed and biotech companies, as the traits don't sem to add much value if the borers are extinct and the rootworms drown.All the drought-tolerance in the world won't help a plant underwater during May and June. DAMHIKT.

Luckily, we're soon to be legislatively freed from any climate change problem. But just in case, that doesn't work, I think I'll have a backup plan.

[Update: for help with the idea of "geopotential meters" this is the best I could do. And I'm still pretty vague.]


Anonymous said...

Present day row crop agriculture only works if we can get in the fields when we need to to till, plant, and harvest. The window seems to be narrowing and it is getting harder and harder especially with more ground to cover. If weather keeps us out of the fields a week or two, it is a real problem. I am waiting for that really bad year which will be even worse than what we have already experienced.

Ron Ellermeier said...

John: Anchored down here in the Lesser Antilles while pricing 2010 soybeans back home gives me an interesting perspective. The reason I was in a fright a few days ago trying to dodge Hurricane Tomas is that the great equatorial conveyor belt of storms is still north of the equator, and, the Tropical Atlantic is still between 85 and 87 degrees F, among other, lessor factors. The reason I'm getting such nice prices for soybeans is the same: the great conveyor belt still hasn't migrated to a position south of the equator, so that stormy lows could form and veer south over Matto Grosso, etc. I can't ascribe a mechanism here, but it is certainly an extreme condition in global weather mechanics. Ron Ellermeier, S/V Wight Skye

Anonymous said...

A couple of questions and a reality check.
1) how big is a geopotential meter? One meter I suspect.
2) How far is one longitudal degree at Bermuda?
This study says the high grew up 6 meters--in terms us old guys understand 6 yard or 9 feet.
Granted a degree is at it's greatest at the equator but it isn't that big and the ridge has moved closer by 9 degrees so how far is that?
In the bigger picture this change is pretty much insignificate.
Dave in Virginia

John Phipps said...


At the equator a degree = 25,000 mi. /360 degrees or about 75 miles more or less. Nine degrees is a big deal.

As for geopotential meters see the update.


Thanks for the news from your part of the globe.


Your thinking matches ours. We're buying [Tier 3] horses and bigger equipment because we think narrower windows will be the norm.