Digital Commons Network^™

Heat Sources Within The Greenland Ice Sheet: Dissipation, Temperate Paleo-Firn And Cryo-Hydrologic Warming, M. P. Lüthi, C. Ryser, L. C. Andrews, G. A. Catania, M. Funk, R. L. Hawley

Dartmouth Scholarship

Ice temperature profiles from the Greenland Ice Sheet contain information on the deformation history, past climates and recent warming. We present full-depth temperature profiles from two drill sites on a flow line passing through Swiss Camp, West Greenland. Numerical modeling reveals that ice temperatures are considerably higher than would be expected from heat diffusion and dissipation alone. The possible causes for this extra heat are evaluated using a Lagrangian heat flow model. The model results reveal that the observations can be explained with a combination of different processes: enhanced dissipation (strain heating) in ice-age ice, temperate paleo-firn, and cryo-hydrologic warming …

A Ten-Year Record Of Supraglacial Lake Evolution And Rapid Drainage In West Greenland Using An Automated Processing Algorithm For Multispectral Imagery, B. F. Morriss, R. L. Hawley, J. W. Chipman, L. C. Andrews

Dartmouth Scholarship

The rapid drainage of supraglacial lakes introduces large pulses of meltwater to the subglacial environment and creates moulins, surface-to-bed conduits for future melt. Introduction of water to the subglacial system has been shown to affect ice flow, and modeling suggests that variability in water supply and delivery to the subsurface play an important role in the development of the subglacial hydrologic system and its ability to enhance or mitigate ice flow. We developed a fully automated method for tracking meltwater and rapid drainages in large (> 0.125 km²) perennial lakes and applied it to a 10 yr time …

Process-Evaluation Of Tropospheric Humidity Simulated By General Circulation Models Using Water Vapor Isotopologues: 1. Comparison Between Models And Observations, Camille Risi, David Noone, John Worden, Christian Frankenberg, Gabriele Stiller, Michael Kiefer, Bernd Funke, Kaley Walker, Peter Bernath, Matthias Schneider, Debra Wunch, Vanessa Sherlock, Nicholas Deutscher, David Griffith, Paul O. Wennberg, Kimberly Strong, Dan Smale, Emmanuel Mahieu, Sabine Barthlott, Frank Hase, Omaira García, Justus Notholt, Thorsten Warneke, Geoffrey Toon, David Sayres, Sandrine Bony, Jeonghoon Lee, Derek Brown, Ryu Uemura, Christophe Sturm

Chemistry & Biochemistry Faculty Publications

The goal of this study is to determine how H₂O and HDO measurements in water vapor can be used to detect and diagnose biases in the representation of processes controlling tropospheric humidity in atmospheric general circulation models (GCMs). We analyze a large number of isotopic data sets (four satellite, sixteen ground-based remote-sensing, five surface in situ and three aircraft data sets) that are sensitive to different altitudes throughout the free troposphere. Despite significant differences between data sets, we identify some observed HDO/H₂O characteristics that are robust across data sets and that can be used to evaluate …

Physical, Chemical, And Biological Data For Detailed Study Of Irrigation Drainage In The San Juan Area, New Mexico, 1993-94, With Supplemental Data, 1991-95, United States Geological Survey

All U.S. Government Documents (Utah Regional Depository)

Investigators collected water, bottom-sediment, soil, and biological samples at more than 50 sites in the San Juan River area during 1993-94. Sample sites included (1) sites located within Department of the Interior irrigation project service areas, or areas that receive drainage from irrigation projects; (2) reference sites for comparison with irrigation project sites; and (3) sites located within the reach of the San Juan River from Navajo Dam to 10 miles downstream from the dam.

Soil Additives And Their Effect On The Yield Of Various Crops And The Physical Properties Of An Agricultural Soil, Gaylen L. Ashcroft

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It is generally accepted that soil structure is very important in keeping productivity at a high level. When soils are loose and friable, mechanical impedance to root growth and seedling emergence is greatly reduced. Such soils infiltrate greater quantities of precipitation, are better aerated, and possess a more favorable temperature than puddled soils. Essential plant nutrients are also more easily available in well aggregated soil.

In the last few years, several synthetic soil additives have been placed on the market. Extravagant claims have been made about the ability of these amendments to maintain soil structure, without a sound body of …