# Northeastern USA Little Ice Age Temperature and Precipitation Reconstructions #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # Template Version 2.0 # NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. # If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/6221 # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/pollen/recons/liadata.txt # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/pollen/recons/conroy1988.txt # # Original_Source_URL: # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Climate Reconstructions # # Parameter_Keywords: air temperature, precipitation #-------------------- # Contribution_Date # Date: 1993-01-04 #-------------------- # Title # Study_Name: Northeastern USA Little Ice Age Temperature and Precipitation Reconstructions #-------------------- # Investigators # Investigators: Gajewski, K. #-------------------- # Description_and_Notes # Description: Mean summer (JJA) temperatures and total annual precipitation for the past 2000 years # reconstructed from pollen from lakes with laminated sediments. The laminations ensure a more precise # time control than normally obtained from radiocarbon. #-------------------- # Publication # Authors: K. Gajewski # Published_Date_or_Year: 1988-05-01 # Published_Title: Late holocene climate changes in eastern North America estimated from pollen data # Journal_Name: Quaternary Research # Volume: 29 # Edition: # Issue: 3 # Pages: 255-262 # Report_Number: # DOI: 10.1016/0033-5894(88)90034-8 # Online_Resource: http://www.sciencedirect.com/science/article/pii/0033589488900348 # Full_Citation: # Abstract: Well-dated pollen profiles from six sites from Maine to Minnesota record vegetation changes indicative of summer temperature and annual precipitation variations over the past 2000 yr. Laminations in the sediment provide accurate time control. Multiple regression techniques were used to calculate calibration functions from a spatial network of modern pollen and climate data. When applied to the six pollen diagrams, these calibration functions yielded estimates that show a long-term trend toward lower summer temperature. Superimposed on this long-term trend are short-term fluctuations that are frequently in phase at the sites. Departures from the long-term cooling trend are positive around 1500 yr ago (indicating relative warmth) and negative between 200 and 500 yr ago (indicating relative cold). Annual precipitation showed a slight increase at several sites during the past 1000 yr relative to the previous 1000 yr. #------------------ # Publication # Authors: K. Gajewski # Published_Date_or_Year: 1987-01-01 # Published_Title: Climatic impacts on the vegetation of eastern North America during the past 2000 years # Journal_Name: Plant Ecology (formerly Vegetatio) # Volume: 68 # Edition: # Issue: 3 # Pages: 179-190 # Report_Number: # DOI: 10.1007/BF00114719 # Online_Resource: http://link.springer.com/article/10.1007/BF00114719 # Full_Citation: # Abstract: Pollen diagrams from seven lakes with annually laminated sediments sampled at 40-year intervals are analyzed to isolate the climatic effects from other effects on the long-term dynamics of vegetation during the past 1000-2000 years along a transect from Maine to Minnesota. Principal components analysis is used to reduce the dimensionality of the pollen data. The pollen records from all lakes show long-term trends, medium frequency oscillations, and higher frequency fluctuations. The long-term trend is associated with the neoglacial expansion of the boreal forest. The mechanism causing this replacement is a change in frequency of air masses in the area. The medium-frequency oscillations are also associated with climate changes, the most recent of which is the 'Little Ice Age'. The climate-related mechanism causing the medium-frequency changes may be changes in disturbance frequency. The higher frequency fluctuations may also be related to disturbance. This analysis of pollen diagrams into time scales of variation has enabled the separation of climate from other factors affecting vegetation dynamics. By comparing the principal components across a transect of sites it proved possible to interpret the climatic effects on vegetation at most sites and not only at range boundaries and 'sensitive' sites. #------------------ # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: ATM-8219079, ATM-7926039, ATM-7423041 #------------------ # Site_Information # Site_Name: Conroy Lake # Location: North America>United States Of America>Maine # Country: United States Of America # Northernmost_Latitude: 46.17 # Southernmost_Latitude: 46.17 # Easternmost_Longitude: -67.53 # Westernmost_Longitude: -67.53 # Elevation: 140 m #------------------ # Data_Collection # Collection_Name: Conroy1988LIA # Earliest_Year: 1940 # Most_Recent_Year: 7 # Time_Unit: Cal. Year BP # Core_Length: m # Notes: #------------------ # Chronology_Information # Chronology: # #---------------- # Variables # # Data variables follow are preceded by "##" in columns one and two. # Data line variables format: Variables list, one per line, shortname-tab-longname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) # ## age_calBP age, , , calendar years before 1975AD, , , , ,N ## temp-JJA surface temperature, , , Deg C, June-July-August, climate reconstructions, , ,N ## precip precipitation, , , mm, annual, climate reconstructions, , ,N # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: # age_calBP temp-JJA precip 7 17.1 1105 14 17.7 1009 21 17.2 1056 28 17.6 1030 35 17.3 1067 42 17.1 963 49 17.7 1028 56 17.6 1047 63 16.8 1055 70 17.2 1057 77 17.3 1023 84 17.4 1051 91 17.3 1042 98 16.6 1022 105 16.9 1039 112 16.9 1058 119 17.1 1119 126 17.5 1039 133 16.7 1075 140 17.3 1007 147 17.5 1025 154 17.0 1044 161 17.0 1014 180 17.9 1016 220 18.2 1030 260 17.5 1006 300 18.1 1005 340 18.0 992 380 18.1 1051 420 18.2 983 460 18.3 1027 500 18.2 1004 540 18.3 1032 580 18.6 925 620 19.0 964 660 18.8 983 700 18.7 998 740 18.5 1005 780 18.2 1012 820 18.6 1009 860 18.6 952 900 19.4 975 940 18.5 989 980 19.2 958 1020 19.0 1007 1060 18.3 985 1100 18.9 994 1140 18.1 956 1180 18.6 937 1220 19.2 981 1260 18.0 964 1300 18.5 991 1340 18.8 936 1380 18.8 979 1420 19.1 957 1460 18.6 1027 1500 18.8 1024 1540 18.8 1017 1580 19.2 950 1620 18.1 955 1660 18.7 955 1700 18.4 958 1740 18.1 1004 1780 17.7 965 1820 19.1 1024 1860 18.5 996 1900 19.2 977 1940 18.7 958