Climatologists are building evidence that crops, particularly corn, are
driving up dew points as they put water into the atmosphere through
evaporation. They also may make corn-growing areas cooler and alter rain
patterns.

Some say the extra moisture could even add energy to thunderstorms, with one
study arguing that a 2001 tornado in Benson got a power boost from corn
evaporation.

"I think there's a new realization that there is a two-way interaction
between weather and agriculture," said Richard Raddatz, a climatologist at
the University of Winnipeg, who has studied the transformation of the
Canadian prairies from grassland to cropland.

In some ways, researchers are taking a second look at a 19th century adage -
"rain follows the plough." Popularised by Charles Dana Wilber in an 1881
book touting the agricultural promise of Nebraska, the phrase supported a
grand notion that the western Great Plains, which in the early 19th century
had been labelled the "Great American Desert," could be transformed into a
garden if people would expose its moist soil to the atmosphere.

Rainy years added credibility to the idea, but it was discredited as
pseudo-science after homesteaders who flooded the plains were trapped by
drought and bankruptcy.

Raddatz, however, said there is a growing body of research indicating that
contemporary crops do indeed change the way water, heat and energy interact
with the atmosphere.

By "transpiring" more heavily than the prairie grasses that preceded them,
and in relatively short periods, crops can generate air movements that can
lead to storms, and intensify the season during which water is cycled
through the atmosphere.

Raddatz published a summary of studies of cropping and weather in February
in the journal Agricultural and Forest Meteorology. They add some oomph to a
2002 study of dew points by Northern Illinois University climatologist David
Changnon, which pinned a 40-year trend toward higher dew points in the
Midwest, and record-high dew points during recent heat waves, on changes in
farming.

Other experts are sceptical.

Assistant Minnesota state climatologist Pete Boulay points out that in the
Twin Cities, average dew points - a measure of water saturation in the air -
during three of the past four summers have been below average. And much of
the corn-rowed state is now in its second consecutive season of very dry
conditions.

But Boulay does believe that a broadly irrigated landscape on the University
of Minnesota St. Paul campus has contributed to dew points there that are
higher than those at broadly paved Minneapolis St. Paul International
Airport.

Peter Robinson, director of the Southeast Regional Climate Center in North
Carolina, has studied dew-point trends nationally and found mixed results,
including an upward nudge in corn-growing areas. But he said he is only
"suspicious the two are related."

University of Oklahoma climatologist Jeff Basara, who has spent most of his
summers in Minnesota, traces a link between corn evaporation and an F2
tornado that injured seven people in Benson on June 11, 2001.

"There was going to be severe weather that day. But evaporation added enough
moisture to the atmosphere and turned it from a day of localized severe
weather reports to a day that really was a headline-maker," said Basara, who
published his research in the Bulletin of the American Meteorological
Society in 2005.

Changnon, the Illinois researcher, found that since 1950, crops had replaced
thousands of square miles of pastureland during the era of rising dew
points. More significant, he said, was the shift in corn-planting from
40-inch rows to 30-inch rows.

"We're just pouring more water into the air," Changnon said.

Changnon said the results of his study shouldn't demonise agriculture but
should prompt urban areas to be alert to the public health threat dew points
in the 70s or higher can bring.

flybywire wrote:
Climatologists are building evidence that crops, particularly corn,
are driving up dew points as they put water into the atmosphere
through evaporation. They also may make corn-growing areas cooler and
alter rain patterns.


.... and couldn't the increase in fine dust particles from ploughing /
exposing dry soil and harvesting of crops, lofted by thermals, help rainfall
by "seeding" the clouds, giving the water vapour something to nucleate
around?

I thought that was the way the article would go when i first started
reading....

Les

--
Remove Frontal Lobes to reply direct.

"These people believe the souls of fried space aliens inhabit their
bodies and hold soup cans to get rid of them. I should care what they
think?"...Valerie Emmanuel

Les Hemmings a.a #2251 SA

good point

Also what about the massive amounts of oilseed rape now in the uk

with the fields near us our summer evenings are now much damper than of old

Mike


"Les Hemmings" wrote in message
...
flybywire wrote:
Climatologists are building evidence that crops, particularly corn,
are driving up dew points as they put water into the atmosphere
through evaporation. They also may make corn-growing areas cooler and
alter rain patterns.


... and couldn't the increase in fine dust particles from ploughing /
exposing dry soil and harvesting of crops, lofted by thermals, help
rainfall by "seeding" the clouds, giving the water vapour something to
nucleate around?

I thought that was the way the article would go when i first started
reading....

Les

--
Remove Frontal Lobes to reply direct.

"These people believe the souls of fried space aliens inhabit their
bodies and hold soup cans to get rid of them. I should care what they
think?"...Valerie Emmanuel

Les Hemmings a.a #2251 SA

On Jul 23, 10:00 am, "flybywire" wrote:

"Les Hemmings" wrote in message
...

flybywire wrote:
Climatologists are building evidence that crops, particularly corn,
are driving up dew points as they put water into the atmosphere
through evaporation. They also may make corn-growing areas cooler and
alter rain patterns.

... and couldn't the increase in fine dust particles from ploughing /
exposing dry soil and harvesting of crops, lofted by thermals, help
rainfall by "seeding" the clouds, giving the water vapour something to
nucleate around?

I thought that was the way the article would go when I first started
reading....

My thoughts went something like:

This sound like the hydrology cycle of the Amazon. So where is the
problem in the forest's rape and destruction?

Deserts? With all those bison. (OK I was thinking buffalo) Then:

Isn't Oklahoma in the Midwest somewhere? Or:

Concrete gives a lower dew point reading than farmland? Wow! I wonder
why all the important readings are from airports? And:

What about all the aquifers they drained and are still draining in the
US and A?

But not necessarily in that order.

In article ,
flybywire writes:
snip
By "transpiring" more heavily than the prairie grasses that preceded them,
and in relatively short periods, crops can generate air movements that can
lead to storms, and intensify the season during which water is cycled
through the atmosphere.

So presumably the results are only intended to apply to North America,
since AIUI most of Britain was covered by forest before it was cleared
for agriculture. I would imagine that a given area of fairly dense
forest would lose more in transpiration than the same area of corn.
--
John Hall

"I am not young enough to know everything."
Oscar Wilde (1854-1900)

i would agree

makes you wonder on the affect of oilseed rape


"John Hall" wrote in message
...
In article ,
flybywire writes:
snip
By "transpiring" more heavily than the prairie grasses that preceded them,
and in relatively short periods, crops can generate air movements that can
lead to storms, and intensify the season during which water is cycled
through the atmosphere.

So presumably the results are only intended to apply to North America,
since AIUI most of Britain was covered by forest before it was cleared
for agriculture. I would imagine that a given area of fairly dense
forest would lose more in transpiration than the same area of corn.
--
John Hall

"I am not young enough to know everything."
Oscar Wilde (1854-1900)

Well, here we are again grasping at the same nonsensical straws as
back in the 1850s!
Remember "Rain follows the plough"? It was the theory back then that
if the US Great Plains were ploughed, rain would increase and turn
"the great American desert' [what it was known as] to forestland.
Even weather service people believed it then.

Here we go again!

Pegleg

On Jul 23, 4:32 am, "flybywire" wrote:
Climatologists are building evidence that crops, particularly corn, are
driving up dew points as they put water into the atmosphere through
evaporation. They also may make corn-growing areas cooler and alter rain
patterns.

Some say the extra moisture could even add energy to thunderstorms, with one
study arguing that a 2001 tornado in Benson got a power boost from corn
evaporation.

"I think there's a new realization that there is a two-way interaction
between weather and agriculture," said Richard Raddatz, a climatologist at
the University of Winnipeg, who has studied the transformation of the
Canadian prairies from grassland to cropland.

In some ways, researchers are taking a second look at a 19th century adage -
"rain follows the plough." Popularised by Charles Dana Wilber in an 1881
book touting the agricultural promise of Nebraska, the phrase supported a
grand notion that the western Great Plains, which in the early 19th century
had been labelled the "Great American Desert," could be transformed into a
garden if people would expose its moist soil to the atmosphere.

Rainy years added credibility to the idea, but it was discredited as
pseudo-science after homesteaders who flooded the plains were trapped by
drought and bankruptcy.

Raddatz, however, said there is a growing body of research indicating that
contemporary crops do indeed change the way water, heat and energy interact
with the atmosphere.

By "transpiring" more heavily than the prairie grasses that preceded them,
and in relatively short periods, crops can generate air movements that can
lead to storms, and intensify the season during which water is cycled
through the atmosphere.

Raddatz published a summary of studies of cropping and weather in February
in the journal Agricultural and Forest Meteorology. They add some oomph to a
2002 study of dew points by Northern Illinois University climatologist David
Changnon, which pinned a 40-year trend toward higher dew points in the
Midwest, and record-high dew points during recent heat waves, on changes in
farming.

Other experts are sceptical.

Assistant Minnesota state climatologist Pete Boulay points out that in the
Twin Cities, average dew points - a measure of water saturation in the air -
during three of the past four summers have been below average. And much of
the corn-rowed state is now in its second consecutive season of very dry
conditions.

But Boulay does believe that a broadly irrigated landscape on the University
of Minnesota St. Paul campus has contributed to dew points there that are
higher than those at broadly paved Minneapolis St. Paul International
Airport.

Peter Robinson, director of the Southeast Regional Climate Center in North
Carolina, has studied dew-point trends nationally and found mixed results,
including an upward nudge in corn-growing areas. But he said he is only
"suspicious the two are related."

University of Oklahoma climatologist Jeff Basara, who has spent most of his
summers in Minnesota, traces a link between corn evaporation and an F2
tornado that injured seven people in Benson on June 11, 2001.

"There was going to be severe weather that day. But evaporation added enough
moisture to the atmosphere and turned it from a day of localized severe
weather reports to a day that really was a headline-maker," said Basara, who
published his research in the Bulletin of the American Meteorological
Society in 2005.

Changnon, the Illinois researcher, found that since 1950, crops had replaced
thousands of square miles of pastureland during the era of rising dew
points. More significant, he said, was the shift in corn-planting from
40-inch rows to 30-inch rows.

"We're just pouring more water into the air," Changnon said.

Changnon said the results of his study shouldn't demonise agriculture but
should prompt urban areas to be alert to the public health threat dew points
in the 70s or higher can bring.