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At least 199 records · Page 11

Hydrologic Model Files (PRMS) for Historical Conditions in the East River Watershed, Colorado between 1987-2019

The data package contains model input and output file for the East River watershed (85 km2) located in the headwaters of the Colorado River. The model is the U.S. Geological Survey (USGS) Precipitation-Modeling Runoff System (PRMS) for the historical, or baseline, condition (1987-2019) to assess the efficiency of summer monsoon rains to generate streamflow. The finite difference grid resolution is 100 m with elevations resampled from the USGS National Elevation Dataset. LANDFIRE raster data is used to derive parameters of dominant cover type, summer and winter cover density, canopy interception characteristics for snow and rain and transmission coefficient for shortwave radiation. Climate forcing uses minimum and maximum daily temperature lapse rates defined by the two Snow Telemetry (SNOTEL) stations located in the vicinity of the East River adjusted for aspect. Schofield SNOTEL snowfall is spatially distributed using LiDAR derived snow depth observations from the Airborne Snow Observatory (ASO) flown 4 April 2016. Snow depths are converted to snow water equivalent based on ground surveys and density modeling. Rainfall is spatially distributed using the monthly Parameter-elevation Relationships on Independent Slopes Model 30-year monthly averages. Simulated solar radiation is calibrated to match weather station observations. Model verification of snow water equivalent (SWE) accumulation and ablation relies on the 2018 and 2019 ASO maps and weather station snow depth. The data package contains model input files in text format, model documentation in pfd and a readme.txt file to help users understand the file structure to run the program.

54 ENVIRONMENTAL SCIENCES↗

Dissolved Oxygen and Temperature Data from the Hyporheic Zone of the East River Watershed July 2017 to October 2018

Dissolved oxygen (DO) is critical for aquatic ecosystems. Our focus is on the long-term DO dynamics in hyporheic zone of rivers, which are a function of both transport (hydrologic exchange between river and hyporheic zone) and uptake by biogeochemical reactions or respiration. The study site is the alpine East River watershed in Colorado, USA, meander A downstream from the pump house. Opti O2 probes were deployed in the water column and directly within the river-bed at 10, 20, and 35 cm depth (38°55'23.38"N, 106°57'4.21"W, 9046.88m) to monitor DO and temperature. A continuous data stream from July 24, 2017 to Oct 24, 2018 was autonomously telemetered to the cloud. This 14-month DO and temperature time series were obtained without any servicing for maintenance or data downloads; additionally the ability to remotely verify probe performance during field deployment was essential to confirm data validity during winter freeze-in and hydrological/weather events, such as spring melt and summer monsoons. We investigate the variations in dissolved oxygen dynamics of this snow-pack dominated watershed during a comparatively low flow water year (2018) and a relatively normal water year (2017), enabled by distinctive, in-situ, high frequency (∆t = 5min) sensors that provided a continuous time-series from the undisturbed study site over multiple seasons.

54 ENVIRONMENTAL SCIENCES↗

Radon Isotopes and Stable Water Isotopes from Coal Creek Watershed, Colorado (2021)

The radon isotope and stable water isotope data for Coal Creek Watershed, Colorado, consists of d2H, d18O, and 222Rn values from samples collected at 8 stream location along Coal Creek, samples from 7 groundwater springs within the watershed, and precipitation isotope samples collected by Next Generation Water Observing System (NGWOS) from a collector within the watershed. All stream and spring samples were collected between June and October, 2021, and precipitation isotope samples were collected between November 2020 and September 2021. These data were collected to evaluate how groundwater contributions to Coal Creek originating from a fractured hillslope and alluvial fan respond to summer monsoon rains and seasonal drying. Understanding of groundwater-surface water interactions in montane systems in critical for the future of water availability in the Western US as groundwater contributions are expected to become more important for sustaining summer stream flows. This data package contains: (1) a csv of all radon samples; (2) a csv of all stream and spring isotope samples; (3) a csv of precipitation isotope samples; and (4) a csv of locations for each sampling site. The dataset additionally includes a file-level metadata (flmd.csv) file that lists each file contained in the dataset with associated metadata; and a data dictionary (dd.csv) file that contains column/row headers used throughout the files along with a definition, units, and data type.

54 ENVIRONMENTAL SCIENCES↗

AmeriFlux US-CMW Charleston Mesquite Woodland

This is the AmeriFlux version of the carbon flux data for the site US-CMW Charleston Mesquite Woodland. Site Description - Site is a riparian mesquite woodland located along an old alluvial terrace along the banks of the San Pedro River in southeastern Arizona. Site climate is semiarid with monsoonal (Jul-Sep) rainfall. The mesquite trees access groundwater from an alluvial aquifer recharged elsewhere. Site water balance is not closed and ET greatly exceeds precipitation. The understory grasses and forbs are rainfall dependent. This groundwater-dependent ecosystem is far more ebulliant and productive than the upland vegetation around it (shrublands and grasslands).

Scott, Russell↗

AmeriFlux US-LS1 San Pedro River Lewis Springs Sacaton Grassland

This is the AmeriFlux version of the carbon flux data for the site US-LS1 San Pedro River Lewis Springs Sacaton Grassland. Site Description - This is a riparian grassland located along an old alluvial terrace along the banks of the entrenched San Pedro River in southeastern Arizona. Site climate is semiarid with monsoonal (Jul-Sep) rainfall. The grasses access groundwater (depth of 2-4 m)from an alluvial aquifer recharged elsewhere. Site water balance is not closed and ET greatly exceeds precipitation. The perennial bunchgrasses use both rainfall, groundwater and occasional flood water. This groundwater-using ecosystem is far more ebulliant and productive than the upland vegetation around it (shrublands and grasslands) outside of the San Pedro River corridor.

Scott, Russell↗

AmeriFlux US-LS2 San Pedro River Lewis Springs Savanna

This is the AmeriFlux version of the carbon flux data for the site US-LS2 San Pedro River Lewis Springs Savanna. Site Description - A riparian savanna located on an old alluvial terrace about 0.5 km from the banks of the entrenched San Pedro River in southeastern Arizona USA. Site climate is semiarid with monsoonal (Jul-Sep) rainfall. The trees access groundwater (depth of ~7 m)from an alluvial aquifer recharged elsewhere. Therefore, site water balance is not closed and ET greatly exceeds precipitation. The perennial bunchgrasses use primarily rainfall. This groundwater-using ecosystem is far more ebulliant and productive than the upland vegetation around it (shrublands and grasslands) outside of the San Pedro River corridor.

Scott, Russell↗

AmeriFlux MX-Aog Alamos Old-Growth tropical dry forest

This is the AmeriFlux version of the carbon flux data for the site MX-Aog Alamos Old-Growth tropical dry forest. Site Description - This tower is located at a patch of remnant old growth tropical dry forest where the dominant vegetation are leguminous trees and a notorious presence of the genus Brusera. The site is at about 18 km from the municipality of Alamos Sonora Mexico within a private ranch managed by the NGO Nature Culture International. The area is also within a federally protected land named “Area de Proteccion de Flora y Fauna Sierra de Alamos Rio-Cuchijaqui" in the catalog of the “Comision Nacional de Areas Naturales Protegidas (CONANP-Mexico)”. The preserved ranch is surrounded by a mosaic of forest patches with different successional stages of tropical dry forest, and some places that are used for local agriculture and livestock. This ecosystem lies in a highly seasonal region under the influence of the North American Monsoon that brings about 70% of the rains from July to September.

Yepez, Enrico A.↗

AmeriFlux MX-Tes Tesopaco, secondary tropical dry forest

This is the AmeriFlux version of the carbon flux data for the site MX-Tes Tesopaco, secondary tropical dry forest. Site Description - This tower was located in the "Ejido la Estrella" where the eddy covariance tower is located 7.5 km east of the town Rosario de Tesopaco, in southeastern Sonora, Mexico. The tower was positioned in the center of a homogeneous flat terrain at the foothills of the Madre Occidental. This ecosystem lies in a highly seasonal region under the influence of the North American Monsoon that brings about 70% of the rains from July to September. The site is dominated by leguminous trees. Some of the dominant species are Lysiloma divaricatum, Ipomoea arborescens, Acacia cochliacantha, Haematoxylum brasiletto, and Celtis reticulata. The mean basal area at the study site is 14.83 ± 3.3m2 ha-1, and the aboveground biomass is estimated to be 43.20±9.5Mgha-1. These values and the high counts of Acacia cochliacantha indicate that the area is a secondary forest with significant management activities in the past.

Yepez, Enrico A.↗

AmeriFlux FLUXNET-1F MX-Tes Tesopaco, secondary tropical dry forest

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site MX-Tes Tesopaco, secondary tropical dry forest. This is the FLUXNET version of the carbon flux data for the site MX-Tes Tesopaco, secondary tropical dry forest produced by applying the standard ONEFlux (1F) software. Site Description - This tower was located in the "Ejido la Estrella" where the eddy covariance tower is located 7.5 km east of the town Rosario de Tesopaco, in southeastern Sonora, Mexico. The tower was positioned in the center of a homogeneous flat terrain at the foothills of the Madre Occidental. This ecosystem lies in a highly seasonal region under the influence of the North American Monsoon that brings about 70% of the rains from July to September. The site is dominated by leguminous trees. Some of the dominant species are Lysiloma divaricatum, Ipomoea arborescens, Acacia cochliacantha, Haematoxylum brasiletto, and Celtis reticulata. The mean basal area at the study site is 14.83 ± 3.3m2 ha-1, and the aboveground biomass is estimated to be 43.20±9.5Mgha-1. These values and the high counts of Acacia cochliacantha indicate that the area is a secondary forest with significant management activities in the past.

Yepez, Enrico A.↗

AmeriFlux FLUXNET-1F US-Ses Sevilleta shrubland

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ses Sevilleta shrubland. This is the FLUXNET version of the carbon flux data for the site US-Ses Sevilleta shrubland produced by applying the standard ONEFlux (1F) software. Site Description - The Sevilleta Desert Shrubland site is located in Larrea-dominated shrubland in the northern Chihuahuan Desert of the Rio Grande Valley, on the Sevilleta National Wildlife Refuge (SNWR). The site is within the McKenzie Flats area of the Sevilleta National Wildlife Refuge (NWR). McKenzie Flats is an extensive (~130 km2), nearly flat, mixed-species desert grassland bounded on the east by Los Pinos Mountains and on the west by the Rio Grande. Historically, this area has been used for livestock grazing; however, the McKenzie Flats have not been grazed since 1973 and the effects of this previous grazing are considered negligible for the purposes of this study. The density of Larrea at this site is 0.9 m-2 , interspersed with C4 perennial grasses (Bouteloua gracilis, B. eriopoda, Sporobolis spp., Hilaria jamesii, Muhlenbergia spp.). Sixty percent of mean annual precipitation comes in isolated, short duration showers during the monsoon season (July – September); the remainder arrives with winter frontal systems, although with considerable year-to-year variation.

Litvak, Marcy↗

AmeriFlux FLUXNET-1F US-LS2 San Pedro River Lewis Springs Savanna

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-LS2 San Pedro River Lewis Springs Savanna. This is the FLUXNET version of the carbon flux data for the site US-LS2 San Pedro River Lewis Springs Savanna produced by applying the standard ONEFlux (1F) software. Site Description - A riparian savanna located on an old alluvial terrace about 0.5 km from the banks of the entrenched San Pedro River in southeastern Arizona USA. Site climate is semiarid with monsoonal (Jul-Sep) rainfall. The trees access groundwater (depth of ~7 m)from an alluvial aquifer recharged elsewhere. Therefore, site water balance is not closed and ET greatly exceeds precipitation. The perennial bunchgrasses use primarily rainfall. This groundwater-using ecosystem is far more ebulliant and productive than the upland vegetation around it (shrublands and grasslands) outside of the San Pedro River corridor.

Scott, Russell↗

AmeriFlux FLUXNET-1F US-MtB Mt Bigelow

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-MtB Mt Bigelow. This is the FLUXNET version of the carbon flux data for the site US-MtB Mt Bigelow produced by applying the standard ONEFlux (1F) software. Site Description - Western slope of Mt. Bigelow; 29 km NE of Tucson, AZ, USA; Mixed evergreen conifer forest; Average canopy height = 10 m; Summer monsoon; 30-m tower installed in 2002; Secondary forest re-established in the 1930s

Barron-Gafford, Greg [University of Arizona]↗

AmeriFlux FLUXNET-1F US-LS1 San Pedro River Lewis Springs Sacaton Grassland

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-LS1 San Pedro River Lewis Springs Sacaton Grassland. This is the FLUXNET version of the carbon flux data for the site US-LS1 San Pedro River Lewis Springs Sacaton Grassland produced by applying the standard ONEFlux (1F) software. Site Description - This is a riparian grassland located along an old alluvial terrace along the banks of the entrenched San Pedro River in southeastern Arizona. Site climate is semiarid with monsoonal (Jul-Sep) rainfall. The grasses access groundwater (depth of 2-4 m)from an alluvial aquifer recharged elsewhere. Site water balance is not closed and ET greatly exceeds precipitation. The perennial bunchgrasses use both rainfall, groundwater and occasional flood water. This groundwater-using ecosystem is far more ebulliant and productive than the upland vegetation around it (shrublands and grasslands) outside of the San Pedro River corridor.

Scott, Russell [USDA-ARS]↗

AmeriFlux FLUXNET-1F MX-Aog Alamos Old-Growth tropical dry forest

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site MX-Aog Alamos Old-Growth tropical dry forest. This is the FLUXNET version of the carbon flux data for the site MX-Aog Alamos Old-Growth tropical dry forest produced by applying the standard ONEFlux (1F) software. Site Description - This tower is located at a patch of remnant old growth tropical dry forest where the dominant vegetation are leguminous trees and a notorious presence of the genus Brusera. The site is at about 18 km from the municipality of Alamos Sonora Mexico within a private ranch managed by the NGO Nature Culture International. The area is also within a federally protected land named “Area de Proteccion de Flora y Fauna Sierra de Alamos Rio-Cuchijaqui" in the catalog of the “Comision Nacional de Areas Naturales Protegidas (CONANP-Mexico)”. The preserved ranch is surrounded by a mosaic of forest patches with different successional stages of tropical dry forest, and some places that are used for local agriculture and livestock. This ecosystem lies in a highly seasonal region under the influence of the North American Monsoon that brings about 70% of the rains from July to September.

Yepez, Enrico A. [Instituto Tecnologico de Sonora]↗

AmeriFlux FLUXNET-1F US-CMW Charleston Mesquite Woodland

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-CMW Charleston Mesquite Woodland. This is the FLUXNET version of the carbon flux data for the site US-CMW Charleston Mesquite Woodland produced by applying the standard ONEFlux (1F) software. Site Description - Site is a riparian mesquite woodland located along an old alluvial terrace along the banks of the San Pedro River in southeastern Arizona. Site climate is semiarid with monsoonal (Jul-Sep) rainfall. The mesquite trees access groundwater from an alluvial aquifer recharged elsewhere. Site water balance is not closed and ET greatly exceeds precipitation. The understory grasses and forbs are rainfall dependent. This groundwater-dependent ecosystem is far more ebulliant and productive than the upland vegetation around it (shrublands and grasslands).

Scott, Russell [USDA-ARS]↗

The Seismic Signature of a High-Energy Density Physics Laboratory and Its Potential for Measuring Time-Dependent Velocity Structure

The Z Machine at Sandia National Laboratories is a pulsed power facility for high-energy density physics experiments that can shock materials to extreme temperatures and pressures through a focused energy release of up to ~ 25 MJ in < 100 nanoseconds. It has been in operation for more than two decades and conducts up to ~ 100 experiments, or “shots,” per year. Based on a set of 74 known shot times from 2018, we determined that Z Machine shots produce detectable ~ 3–17 Hz ground motion 12 km away at the Albuquerque Seismological Laboratory, New Mexico (ANMO), borehole seismograph, with peak signal at ~ 7 Hz. The known shot waveforms were used to create a three-component template, leading to the detection of 2339 Z Machine shots since 1998 through single-station cross-correlation. Local seismic magnitude estimates range from local magnitude (M L ) —2 to —1.3 and indicate that only a small fraction of the shot energy is transmitted by seismic phases observable at 12 km distance. The most recent major facility renovation, which was intended to decrease mechanical dissipation, is associated with an abrupt decrease in observed seismic amplitudes at ANMO despite stable maximum shot energy. The highly repetitive impulsive sources are well suited to coda-wave interferometry to investigate time-dependent velocity structures. Relative velocity variations (dv/v) show an annual cycle with amplitude of ~ 0.2%. Local minima are observed in the late spring, and dv/v increases through the summer monsoon rainfall, possibly reflecting patchy saturation as rainfall infiltrates near the eastern edge of the Albuquerque basin. Importantly, the cumulative results demonstrate that forensic seismology can provide insight into long-term operation of facilities such as pulsed-power laboratories, and that their recurring signals may be valuable for studies of time-dependent structure

54 ENVIRONMENTAL SCIENCES↗

Reducing the risks of wildfires

Anyone who has lived in New Mexico for at least a year realizes that the Land of Enchantment has six seasons. In addition to the four seasons everyone else has, we have a wildfire season, which typically comes during late spring and early summer. Wildfires sometimes even last through the monsoon season, when thunderstorms are lighter than usual. Wildfires, it seems, are inevitable in Los Alamos and the surrounding communities that make up part of northern New Mexico. In recent history, the 2000 Cerro Grande Fire destroyed 150,000 acres (including 7,500 acres of Laboratory property) and 235 Los Alamos homes. In 2011, the Las Conchas Fire burned more than 156,000 acres and threatened Los Alamos and the Lab. To minimize the chances of wildfires and to strengthen defenses against wildfires, the Laboratory every year carries out various fire-mitigation strategies throughout its 42 square miles.

54 ENVIRONMENTAL SCIENCES↗

Paleo-Megadroughts and Abrupt Climate Changes in the Speleothem Records. Final report

This project is motivated by the speleothem isotope records in Asia, which show regional responses in the hydrologic cycle to different climate forcings. Speleothem isotopic records are typically interpreted in terms of local precipitation variations or monsoon intensity. Our study demonstrates that non-local processes also play an important role. We started this project to understand the regional difference in speleothem isotopic composition between the Last Glacial Maximum (LGM) and the present-day. The record in Southwest China showed greater depletion during the LGM compared to those in East China. Our modeling and analysis showed that speleothems record, in addition, large scale changes in atmospheric circulation and moisture transport and their subsequent impact on precipitation. We developed an algorithm to partition total precipitation according to their formation dynamics, namely into frontal and non-frontal precipitation, and showed that the two have different trends and hence different causal mechanism. We then focused our subsequent attention on circulation impacts on precipitation changes. We applied a machine learning algorithm to detect rainbands in the ERA-Interim reanalysis product, and showed that the seasonal migrations of the rainbands are tied to the seasonal migrations of the jet stream, in particular the northerlies of the jet meanders. These northerlies, in turn, are partly topographic Rossby waves excited as the upstream westerlies impinge on the Tibetan Plateau. The seasonal variations of these upstream westerlies thus contribute to the seasonal movements of the rainbands and regional precipitation changes. Our analysis of the modern precipitation isotope record further confirms the importance of jet stream changes in the isotopic variations and shows that isotope-enriched years have reduced summer seasonality, with less pronounced northward migration of the jet.

54 ENVIRONMENTAL SCIENCES↗