Some of the Many Applications of Archaeoclimatology Katherine McEnaney and Reid Bryson (The powerpoint will run itself automatically on the ‘slideshow’

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


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



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


Example: La Crosse, WIExample: La Crosse, WIMODELED PRECIPITATION HISTORY

LA CROSSE, WI

0

200

400

600

800

1000

1200

1400

1600

-14000 -12000 -10000 -8000 -6000 -4000 -2000 0

RADIOCARBON DATE BP

ANNUAL PRECIPITATION mm

0

20

40

60

80

100

120

140

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


Example: La Crosse, WIExample: La Crosse, WIMODELED WATER SUPPLY HISTORY

LA CROSSE, WI

500

600

700

800

900

1000

1100

1200

1300

1400

1500

-14000 -12000 -10000 -8000 -6000 -4000 -2000 0

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


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


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


Discharge of the MississippiDischarge of the MississippiMODELED DISCHARGE HISTORY

Mississippi River at Winona, MN

0

500

1000

1500

2000

2500

3000

3500

4000

4500

-14000 -12000 -10000 -8000 -6000 -4000 -2000 0

RADIOCARBON DATE BP

MEAN MONTHLY DISCHARGE m^3/s

AVE MONTHLY DISCHARGE



The Effect of the onset of The Effect of the onset of the Holocene is obviousthe Holocene is obvious

Northern Example: Dinwoody Creek, Wyoming



Stream DischargeStream DischargeMODELED DISCHARGE HISTORYDinwoody Creek at Dubois, WY

0

200

400

600

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1000

1200

1400

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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

0

10

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50

60

-14000 -12000 -10000 -8000 -6000 -4000 -2000 0


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

0

2000

4000

6000

8000

10000

12000

14000

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RADIOCARBON DATE BP

ANNUAL SNOWFALL mm

ANNUAL SNOWFALL

These storms also brought more snow



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



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


Hurricanes Farther NorthHurricanes Farther North

Cape Cod


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

-14000 -12000 -10000 -8000 -6000 -4000 -2000 0

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


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

0

10

20

30

40

50

60

-14000 -12000 -10000 -8000 -6000 -4000 -2000 0


ANNUAL STORMS per MONTH

0

2

4

6

8

10

12

14

16

18

JULY/AUG STORMS per MONTH

ANNUAL Storms JULY AUGUST



Modeled Fire HazardModeled Fire HazardMODELED POTENTIAL FIRE HAZARD

Santa Fe, NM

0

2

4

6

8

10

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18

-14000 -12000 -10000 -8000 -6000 -4000 -2000 0


JULY DEWPOINT

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18

JULY STORMS per MONTH

JULY DEWPOINT JULY STORMS

Stormy with Dry Air



Dune MovementDune Movement

Departure of ice from the Cochrane Moraine

may have increased dune movement in Southern Manitoba


Dune MovementDune MovementMODELED SCALAR DRIFT POTENTIAL

Brandon, Manitoba

35

40

45

50

55

60

-10000 -8000 -6000 -4000 -2000 0

RADIOCARBON DATE BP

Drift Potential

0

20

40

60

80

100

120

140

160

180

JAN DRIFT AUG DRIFT

Note the dramatic increase in drift

potential after 8000


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


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


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 . .

Documents

Some of the Many Applications of Archaeoclimatology Katherine McEnaney and Reid Bryson (The powerpoint will run itself automatically on the ‘slideshow’