# Upper Midwest USA Last Millennium Summer 2m Air Temperature #----------------------------------------------------------------------- # World Data Center for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, title, online resource and date accessed. # # Description/Documentation lines begin with # # Data lines have no # # # Online_Resource: http://www.ncdc.noaa.gov/paleo/study/17133 # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/pollen/recons/northamerica/wahl2012/wahl2012-darklake.txt # # Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/pollen/recons/liadata.txt # # Archive: Climate Reconstructions #--------------------------------------- # Contribution_Date # Date: 2014-09-02 #--------------------------------------- # Title # Study_Name: Upper Midwest USA Last Millennium Summer 2m Air Temperature #--------------------------------------- # Investigators # Investigators: Wahl, Eugene; Diaz, Henry; Ohlwein, Christian #--------------------------------------- # Description and Notes # Description: Fossil pollen from three lakes in Wisconsin USA are used (Dark Lake, Ruby Lake, Little Pine Lake) along with modern pollen-climate relationships from the North American Pollen Data Base #--------------------------------------- # Publication # Authors: Wahl, E., H. Diaz, and C. Ohlwein # Published_Date_or_Year: 2012 # Published_Title: A pollen-based reconstruction of summer temperature in central North America and implications for circulation patterns during medieval times # Journal_Name: Global and Planetary Change # Volume: 84-85 # Issue: # Pages: 66-74 # Report Number: # DOI: 10.1016/j.gloplacha.2011.10.005 # Abstract: We present a reconstruction of mean summer temperature for the northern Midwest of theUSA based on lacustrine pollen records from three different lakes in Wisconsin. The results suggest a relatively warm period during the earlier part of the record (~1200–1500 CE) followed by a cooler Little Ice Age (~1500–1900) and a subsequent warming to modern conditions. The reconstructed modern summer mean temperature is in good agreement with observations, and the decades of the 1930s to 1950s appear to be the warmest such period in the proxy record (through 1974). Analyses of circulation features associated with the warmest summers in the recent climate record suggest a prevalence of continental ridging accompanied by generally dry conditions during these warm summers in the Midwest. Drought reconstruction using the Palmer Drought Severity Index (PDSI) and tree-ring records as predictors also yield relatively dry conditions in medieval times for the central US. As reported in a number of recent studies, possible forcing mechanisms include La Niña-like conditions in the equatorial Pacific and warmer than average waters in the tropical Indo-western Pacific Ocean possibly coupled to a positive mode of the AMO/ NAO North Atlantic circulation pattern. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: 0724619 #--------------------------------------- # Site Information # Site_Name: Dark Lake # Location: Wisconsin # Country: United States # Northernmost_Latitude: 45.275 # Southernmost_Latitude: 45.275 # Easternmost_Longitude: -91.475 # Westernmost_Longitude: -91.475 # Elevation: 334 #--------------------------------------- # Data_Collection # Collection_Name: Dark Lake Temp W12 # First_Year: 1045 # Last_Year: 1965 # Time_Unit: AD # Core_Length: # Notes: Reconstruction using inversion of a climate-to-pollen forward model (the binomial-logistic Generalized Linear Model applied to pollen count ratios) #--------------------------------------- # Chronology: #--------------------------------------- # Variables # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## age_AD ,age,,,years AD,,,, ## temp_2m-JJA-t99% ,2m Air Temperature,,top 99%,degrees C,,Climate Reconstructions,,Binomial-logistic Generalized Linear Model ## temp_2m-JJAmid ,2m Air Temperature,,,degrees C,Climate Reconstructions,Climate Reconstructions,mid-range,Binomial-logistic Generalized Linear Model ## temp_2m-JJA-b99% ,2m Air Temperature,,bottom 99%,degrees C,Climate Reconstructions,Climate Reconstructions,,Binomial-logistic Generalized Linear Model # Data # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Value: N/A age_AD temp_2m-JJA-t99% temp_2m-JJAmid temp_2m-JJA-b99% 1965 19.95407 19.64975 19.38067 1955 20.64407 20.18072 19.82074 1945 20.30872 19.91279 19.58833 1935 20.73074 20.28708 19.93911 1925 20.32319 19.91585 19.58801 1915 20.13832 19.69854 19.33951 1905 19.51092 19.13191 18.76579 1895 19.70991 19.3149 18.95452 1885 19.18329 18.8068 18.39956 1875 19.60282 19.24419 18.90511 1865 19.83434 19.4974 19.20016 1855 19.53984 19.24431 18.96849 1845 19.15649 18.88769 18.60907 1835 19.33537 19.07036 18.81114 1825 18.9883 18.73443 18.4634 1815 18.6623 18.39507 18.09095 1805 18.77827 18.52697 18.24812 1795 18.98107 18.74147 18.48661 1785 18.66827 18.41663 18.13413 1775 19.20619 18.97724 18.74786 1765 19.47763 19.20706 18.95107 1729 19.33406 19.07029 18.81194 1689 19.85364 19.48068 19.16105 1651 19.45044 19.17417 18.91188 1611 19.59307 19.28026 18.98913 1573 20.19733 19.87709 19.60307 1525 19.98026 19.70115 19.45371 1484 20.39778 20.05584 19.77152 1445 19.60256 19.36253 19.13639 1405 19.92914 19.5844 19.28538 1365 20.11606 19.77363 19.48454 1325 20.21915 19.84786 19.53688 1285 20.23849 19.87807 19.57857 1245 19.88563 19.62926 19.39597 1205 20.15231 19.84765 19.58108 1165 20.20902 19.81419 19.48507 1125 20.11263 19.78724 19.50806 1085 19.64749 19.30952 18.9951 1045 19.93589 19.59251 19.2947