Some of the Many Some of the Many Applications of Applications of
ArchaeoclimatologyArchaeoclimatology
Katherine McEnaneyKatherine McEnaney
andand
Reid BrysonReid Bryson
(The powerpoint will run itself automatically on the ‘slideshow’ setting)
Intro Local Large Scale Storms Dunes Composite
ArchaeoclimatologyArchaeoclimatology
Sometimes called Macrophysical Sometimes called Macrophysical modelingmodeling
Tested hundreds of times against Tested hundreds of times against field datafield data
Based on Based on – orbital forcing of incoming radiationorbital forcing of incoming radiation– modulation by aerosols and variable modulation by aerosols and variable
snow-ice albedosnow-ice albedo– standard dynamicsstandard dynamics– synoptic climatologysynoptic climatology
Intro Local Large Scale Storms Dunes Composite
ArchaeoclimatologyArchaeoclimatology
Site specificSite specific Yields monthly 200 year mean valuesYields monthly 200 year mean values
This makes the method uniqueThis makes the method unique
It [is now] possible to produce 100 It [is now] possible to produce 100 year resolution for the past 20,000+ year resolution for the past 20,000+ yearsyears
Intro Local Large Scale Storms Dunes Composite
Example: La Crosse, WIExample: La Crosse, WIMODELED PRECIPITATION HISTORY
LA CROSSE, WI
0
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RADIOCARBON DATE BP
ANNUAL PRECIPITATION mm
0
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60
80
100
120
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MONTHLY PRECIPITATION mm
ANNUAL JAN prec JULY prec
Late A Middle Archaic Early Archaic Paleoindian Woodland
La Crosse appears to have had twice as much precipitation in
Late Pleistocene and Early Holocene times
Summer rains were less
important in Mid Holocene
Heaviest rains have shifted to summer
Intro Local Large Scale Storms Dunes Composite
Example: La Crosse, WIExample: La Crosse, WIMODELED WATER SUPPLY HISTORY
LA CROSSE, WI
500
600
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1200
1300
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RADIOCARBON DATE BP
ANNUAL POT'L. EVAPO-TRANS. mm
ANNUAL PREC. ANNUAL POTL. EVAP.
Oak Savannah Grassland Mesic Forest Boreal Forest
The difference between precipitation and
evaporation is known as water stress
Boreal Forests have an abundance of
precipitation
More recent times have a great deal of
variabilityGrasslands have a
deficit of precipitation
Intro Local Large Scale Storms Dunes Composite
Large Scale FeaturesLarge Scale Features
Large scale features may be modeledLarge scale features may be modeled
– Sea IceSea Ice– Large River Large River
DischargeDischarge
MODELED GREENLAND SEA ICE
1.05
1.075
1.1
1.125
1.15
1.175
1.2
1.225
1.25
-14000 -12000 -10000 -8000 -6000 -4000 -2000 0
RADIOCARBON DATE BP
FEB ICE AREA 10E6 kmsq
0.52
0.54
0.56
0.58
0.6
0.62
0.64
0.66
AUG ICE AREA 10E6 kmsq
FEB ICE AUG ICE
Intro Local Large Scale Storms Dunes Composite
Large Scale FeaturesLarge Scale Features
In the far north, human usage of an In the far north, human usage of an area seems to be related to sea icearea seems to be related to sea ice
MODELED SEA ICE HISTORYChukchi Sea
0.2575
0.26
0.2625
0.265
0.2675
0.27
0.2725
-6000 -5000 -4000 -3000 -2000 -1000 0
RADIOCARBON DATE BP
OPEN WATER AREA 10E6 kmsq
OPEN WATER
Palisades
Denbigh
Old Whaling
Choris
Norton
Ipiutak
Birnirk
Thule
Eskimo
Intro Local Large Scale Storms Dunes Composite
Discharge of the MississippiDischarge of the MississippiMODELED DISCHARGE HISTORY
Mississippi River at Winona, MN
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4500
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RADIOCARBON DATE BP
MEAN MONTHLY DISCHARGE m^3/s
AVE MONTHLY DISCHARGE
Intro Local Large Scale Storms Dunes Composite
Intro Local Large Scale Storms Dunes Composite
The Effect of the onset of The Effect of the onset of the Holocene is obviousthe Holocene is obvious
Northern Example: Dinwoody Creek, Wyoming
Intro Local Large Scale Storms Dunes Composite
Intro Local Large Scale Storms Dunes Composite
Stream DischargeStream DischargeMODELED DISCHARGE HISTORYDinwoody Creek at Dubois, WY
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RADIOCARBON DATE B.P.
MEAN ANNUAL Discharge m^3/s
0
1000
2000
3000
4000
5000
6000
7000
MEAN MONTHLY Discharge m^3/s
ANNUAL Discharge MAY JUNE
In Late Pleistocene time the river appears to have been frozen to the bottom with no winter discharge, even
in May.
The snowmelt of June produced an enormous
freshet.
In the warmer, less snowy, Holocene the freshet was greatly reduced and there
was winter discharge.
In the Holocene, there were times of greater discharge.
MODELED STORM FREQUENCY HISTORY
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RADIOCARBON DATE B.P.
ANNUAL STORMS per MONTH
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
JUNE STORMS per MONTH
ANNUAL Storms JUNE
These are associated with an increase in westerly storms, not local events.
Storms and SnowStorms and SnowMODELED SNOWFALL HISTORY
Dubois, WY
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RADIOCARBON DATE BP
ANNUAL SNOWFALL mm
ANNUAL SNOWFALL
These storms also brought more snow
Intro Local Large Scale Storms Dunes Composite
Intro Local Large Scale Storms Dunes Composite
Hurricane or Typhoon frequencyHurricane or Typhoon frequency Thunderstorm frequencyThunderstorm frequency High Tropical HumiditiesHigh Tropical Humidities Changing Prevailing Winds, DunesChanging Prevailing Winds, Dunes
Farther south, there are Farther south, there are different problemsdifferent problems
Intro Local Large Scale Storms Dunes Composite
Intro Local Large Scale Storms Dunes Composite
HurricanesHurricanes
Hurricanes are important Hurricanes are important – Winds and storm surges Winds and storm surges – Heavy rains from their residualsHeavy rains from their residuals
Heavy Rains, “Gully-washers” are Heavy Rains, “Gully-washers” are often associated with deep masses often associated with deep masses of moist air originating in Tropical of moist air originating in Tropical Storms and intruding into the Storms and intruding into the WesterliesWesterlies
Intro Local Large Scale Storms Dunes Composite
Hurricanes Farther NorthHurricanes Farther North
Cape Cod
Intro Local Large Scale Storms Dunes Composite
Hurricanes Farther NorthHurricanes Farther North
Tropical storm number can be modeledTropical storm number can be modeledMODELED TROPICAL CYCLONES
Cape Cod, MA
0
0.5
1
1.5
2
2.5
3
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RADIOCARBON DATE BP
ANNUAL TROPICAL CYCLONES
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
SEPT TROPICAL CYCLONES
ANNUAL SEPT
Intro Local Large Scale Storms Dunes Composite
Modeled Fire HazardModeled Fire Hazard Thunderstorm frequency is important Thunderstorm frequency is important
in areas prone to firesin areas prone to firesMODELED THUNDERSTORM FREQUENCY
HISTORY
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RADIOCARBON DATE B.P.
ANNUAL STORMS per MONTH
0
2
4
6
8
10
12
14
16
18
JULY/AUG STORMS per MONTH
ANNUAL Storms JULY AUGUST
Intro Local Large Scale Storms Dunes Composite
Intro Local Large Scale Storms Dunes Composite
Modeled Fire HazardModeled Fire HazardMODELED POTENTIAL FIRE HAZARD
Santa Fe, NM
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RADIOCARBON DATE B.P.
JULY DEWPOINT
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16
18
JULY STORMS per MONTH
JULY DEWPOINT JULY STORMS
Stormy with Dry Air
Intro Local Large Scale Storms Dunes Composite
Intro Local Large Scale Storms Dunes Composite
Dune MovementDune Movement
Departure of ice from the Cochrane Moraine
may have increased dune movement in Southern Manitoba
Intro Local Large Scale Storms Dunes Composite
Dune MovementDune MovementMODELED SCALAR DRIFT POTENTIAL
Brandon, Manitoba
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45
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55
60
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RADIOCARBON DATE BP
Drift Potential
0
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60
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100
120
140
160
180
JAN DRIFT AUG DRIFT
Note the dramatic increase in drift
potential after 8000
Intro Local Large Scale Storms Dunes Composite
Composite Composite StudiesStudies
Models may be Models may be combined for a combined for a given state/regiongiven state/region
The results may The results may be used to map be used to map precipitation precipitation values or values or anomalies anomalies through the pastthrough the past
Intro Local Large Scale Storms Dunes Composite
In SummaryIn Summary
Almost any important climatic Almost any important climatic variable may be modeledvariable may be modeled
Models are site-specific and high Models are site-specific and high resolutionresolution
Models are economicalModels are economical There seem to be no competitive There seem to be no competitive
modelsmodels
Intro Local Large Scale Storms Dunes Composite
Please cite asPlease cite as
McEnaney, K. A. and R. A. BrysonMcEnaney, K. A. and R. A. Bryson
20052005 Some of the Many Applications of Some of the Many Applications of Archaeoclimatology. Paper presented at Archaeoclimatology. Paper presented at the Wisconsin Archaeological Survey the Wisconsin Archaeological Survey Research Reports Meeting, April 23, 2005, Research Reports Meeting, April 23, 2005, Madison, WI.Madison, WI.
For more information, please contact For more information, please contact [email protected]@wisc.edu or or [email protected]@wisc.edu . .