what’s normal? 26-29 june 2011
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What’s Normal? 26-29 June 2011. Edward J. Hopkins, Assistant Wisconsin State Climatologist Dept. of Atmospheric & Oceanic Sciences University of Wisconsin-Madison. Background. “Normals” Way of depicting an expected climate state based upon statistics over a long-time span. - PowerPoint PPT PresentationTRANSCRIPT
2011 Summer AERA Training 1
What’s Normal?What’s Normal?26-29 June 201126-29 June 2011
Edward J. Hopkins, Edward J. Hopkins, Assistant Wisconsin State ClimatologistAssistant Wisconsin State ClimatologistDept. of Atmospheric & Oceanic SciencesDept. of Atmospheric & Oceanic SciencesUniversity of Wisconsin-MadisonUniversity of Wisconsin-Madison
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BackgroundBackground
“Normals” – Way of depicting an expected climate state based upon
statistics over a long-time span.
What normals include:– Averages– Frequencies– Percentiles
Standardized International Agreement– National Weather Service and National Climatic Data
Center following international agreement to update the 30-year “normals” every ten years.
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Background (con’t.)Background (con’t.)
Why 30-year time length? – Climate is always changing!– Three-decade time-span deemed appropriate – Not too long to cover-up long-term changes in climate– Not too short for an uneven set of statistics due to year-
to-year or decadal changes in weather & climate.
Current climate normal interval covers 1971-2000 averaging period, but wait…
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Long-term temperature record
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Modifying the normalsModifying the normals
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Modifying the normalsModifying the normals
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Modifying the normalsModifying the normals
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Modifying the normalsModifying the normals
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Modifying the normalsModifying the normals
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Modifying the normalsModifying the normals
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Modifying the normalsModifying the normals
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New NormalsNew Normals
National Climatic Data Center is computing new normals of station – temperature (maximum, minimum and average), – precipitation, – snowfall and snow cover – heating and cooling degree day information.
Normals for all these variables will be for daily, monthly, seasonal and annual time scales.
For 250 Local Climatological Data stations:– Hourly averages will include humidity & wind
information.
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Climate StationsClimate Stations
Temperature Temperature ~7500 stations~7500 stations
PrecipitationPrecipitation~8700 stations~8700 stations
Snow Snow ~ 6400 stations~ 6400 stations
Snow depthSnow depth~5300 stations~5300 stations
Hourly Hourly ~260 stations~260 stations
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New Normals ScheduleNew Normals Schedule
1 July 2011 -- New 1981-2010 normals of temperature, precipitation & degree days made available to public.
1 Aug 2011 --NWS begins use on workstations.
31 Dec 2011 --All other normals (the “ag normals”).
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Preliminary ResultsPreliminary Results
Changes between 1971/2000 & 1981/2010 due to:– Changes in climate– Changes in stations, instruments & observing procedures
New normal temperatures – Slightly higher than previous normals for many areas of nation.– Due to inclusion of warm 2000-2009 interval.
Increases in temperature are not uniform across nation and from season to season.
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How do new normals differ?How do new normals differ?Source: A. Arguez, NCDC (Jun 2011)
Summer – Jul Max Temps
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How do new normals differ?How do new normals differ?Source: A. Arguez, NCDC (Jun 2011)
Winter – Jan Min Temps
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Changes for WisconsinChanges for Wisconsin
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Changes for WisconsinChanges for Wisconsin
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For more informationFor more information
NCDCNCDChttp://www.ncdc.noaa.gov/oa/http://www.ncdc.noaa.gov/oa/climate/normals/newnormals.htmlclimate/normals/newnormals.html
Or email Or email [email protected]@aos.wisc.edu from from http://www.aos.wisc.edu/~sco http://www.aos.wisc.edu/~sco
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The Wisconsin State Climatology Office Web PageThe Wisconsin State Climatology Office Web Page
http://www.aos.wisc.edu/~scohttp://www.aos.wisc.edu/~sco
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Views of State Climatology OfficeViews of State Climatology Office
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1919thth Century Weather Data Century Weather Data