DOI: 10.25921/9wrz-eb74
title: NOAA/WDS Paleoclimatology - Wyoming 17KYr Lake Sediment Data and Moisture Balance Reconstructions

description: Sediment-based reconstructions of late-Quaternary lake levels provide direct evidence of hydrologic responses to climate change, but many studies only provide approximate lake elevation curves. Here, we demonstrate a new method for producing quantitative time series of lake elevation based on the facies and elevations of multiple cores collected from a lake's margin. The approach determines the facies represented in each core using diagnostic data, such as sand content, and then compares the results across cores to determine the elevation of the littoral zone over time. By applying the approach computationally, decisions are made systematically and iteratively using different facies classification schemes to evaluate the associated uncertainty. After evaluating our assumptions using ground-penetrating radar (GPR), we quantify past lake-elevation changes, precipitation minus evapotranspiration (DeltaP-ET), and uncertainty in both at Lake of the Woods and Little Windy Hill Pond, Wyoming. The well correlated (r=0.802+/-0.002) reconstructions indicate that water levels at both lakes fell at >11,300, 8000-5500, and 4700-1600 cal yr BP when DeltaP-ET decreased to -50 to -250 mm/yr. Differences between the reconstructions are typically small (10+/-24 mm/yr since 7000 cal yr BP), and the similarity indicates that our reconstruction method can produce statistically-comparable paleohydrologic datasets across networks of sites.
description: Sediment loss-on-ignition (LOI) or sand content data and moisture balance (lake-level and DeltaP-E, 
Precipitation minus Evaporation) reconstructions for Little Windy Hill Pond and Lake of the Woods, Wyoming. 
Also included are facies thresholds for differentiating littoral and sub-littoral lake sediment facies 
based on the raw core data, for use in the iterative lake-level reconstruction process. The reconstruction 
process iteratively applies each set of thresholds in R to produce an ensemble of reconstructions. The code for 
generating the lake-level reconstruction according to the process described in Pribyl and Shuman (2014) is provided.
Also included are the ensemble mean lake-level reconstruction and its uncertainty per 50-yr interval for the length 
of the record, and the individual ensemble members for each time step (but without the ages for the steps).
 R script MoistureBalance is the code for the simple moisture-budget calculation based on the lake-level reconstruction. 
 Again this follows Pribyl and Shuman (2014).  PErecon contains the median P-E reconstruction as an anomaly from modern 
for each 50-yr interval, as well as the 1-sigma and 25% and 75% quantiles of the reconstruction uncertainty.
Data and R code are included in original contributor files: LOW_Cores.csv, LOW_Iterations_011414.csv, 
LOW_LLrecon_011414.csv, LOW_PErecon_011414.csv, LOW_R_Script_LLRecon_012414.txt, LOW_R_Script_MoistureBalance_011414.txt, 
FaciesThresholds_LOW.csv, LWH_Cores.csv, LWH_Iterations_011414.csv, LWH_LLrecon_011414.csv, LWH_PErecon_011414.csv, 
 LWH_R_Script_LLRecon_012414.txt, LWH_R_Script_MoistureBalance_011414.txt, FaciesThresholds_LWH.csv, 
plus WDC Paleo formatted text files woods2014sand.txt, woods2014ll.txt, woods2014p-e.txt, little-windy2014loi.txt, 
little-windy2014ll.txt, and little-windy2014p-e.txt.