Coolerado Cooler Helps to Save Cooling Energy and Dollars: New Cooling Technology Targets Peak Load Reduction

This document is about a new evaporative cooling technology that can deliver cooler supply air temperatures than either direct or indirect evaporative cooling systems, without increasing humidity. The Coolerado Cooler technology can help Federal agencies reach the energy-use reduction goals of EPAct 2005, particularly in the western United States

Fort Carson Wind Resource Assessment

This report focuses on the wind resource assessment, the estimated energy production of wind turbines, and economic potential of a wind turbine project on a ridge in the southeastern portion of the Fort Carson Army base

Development and Evaluation of High Resolution Simulation Tools to Improve Fire Weather Forecasts

Fire weather forecasts rely on numerical weather simulations where the grid size is 4 km x 4 km or larger. In areas of complex terrain, this model resolution will not capture the details of wind flows associated with complicated topography. Wind channeling in valleys, wind speed-up over mountains and ridges, and enhanced turbulence associated with rough terrain and tall forest canopies are poorly represented in current weather model applications. A number of numerical wind flow models have been developed for simulating winds at high resolution; however, there are limited observational data available at the spatial scales appropriate for evaluating these types of models. In response to this need for high resolution validation data, we collected wind measurements at very high spatial resolution over a range of meteorological conditions from three different types of terrain/landcover features: an isolated mountain covered predominantly by grass and sagebrush, a steep river canyon covered predominantly by grass, and a dissected montane drainage with a tall forest canopy. We used data from the isolated mountain and the steep river canyon to evaluate surface wind predictions from routine weather forecasts and a high resolution wind simulation model, WindNinja, developed specifically for fire behavior applications. Data from the third field site will be used for future model evaluations planned to investigate the effect of tall forest canopies on surface wind predictions. Analyses of observations from the isolated mountain and steep river canyon sites indicate that operational weather model (i.e., with numerical grid resolutions of around 4 km or larger) wind predictions are not likely to be good predictors of local near-surface winds (i.e., at sub-grid scales) in complex terrain. Under periods of weak synoptic forcing, surface winds tended to be decoupled from large-scale flows, and under periods of strong synoptic forcing, variability in surface winds was sufficiently large due to terrain-induced mechanical effects that a large-scale mean flow would not be representative of surface winds at most locations on or within the terrain feature. These findings are reported in a manuscript titled “High Resolution Observations of the Near-Surface Wind Field over an Isolated Mountain and in a Steep River Canyon” submitted for publication in Atmospheric Chemistry and Physics. Links to the observed data from this effort as well as an online interface to query, visualize, summarize, and download subsets of the data are available at: http://www.firemodels.org/index.php/windninja-introduction/windninja-publications. Findings from the model evaluations work indicate that using WindNinja to downscale from numerical weather prediction (NWP) model winds can, in some cases, improve the accuracy of surface wind forecasts in complex terrain. Predictions of surface wind speeds and directions improved with downscaling via WindNinja when flow features induced by large scale effects were adequately captured by the NWP model used to initialize WindNinja. This suggests that WindNinja could be incorporated into current fire forecast methods to provide better short-term forecasts for fire management operations. These findings are reported in a manuscript titled “Downscaling Surface Wind Predictions from Numerical Weather Prediction Models in Complex Terrain with a Mass-consistent Wind Model” that will be submitted to the Journal of Applied Meteorology and Climatology later this spring

Development and Evaluation of High Resolution Simulation Tools to Improve Fire Weather Forecasts

Fire weather forecasts rely on numerical weather simulations where the grid size is 4 km x 4 km or larger. In areas of complex terrain, this model resolution will not capture the details of wind flows associated with complicated topography. Wind channeling in valleys, wind speed-up over mountains and ridges, and enhanced turbulence associated with rough terrain and tall forest canopies are poorly represented in current weather model applications. A number of numerical wind flow models have been developed for simulating winds at high resolution; however, there are limited observational data available at the spatial scales appropriate for evaluating these types of models. In response to this need for high resolution validation data, we collected wind measurements at very high spatial resolution over a range of meteorological conditions from three different types of terrain/landcover features: an isolated mountain covered predominantly by grass and sagebrush, a steep river canyon covered predominantly by grass, and a dissected montane drainage with a tall forest canopy. We used data from the isolated mountain and the steep river canyon to evaluate surface wind predictions from routine weather forecasts and a high resolution wind simulation model, WindNinja, developed specifically for fire behavior applications. Data from the third field site will be used for future model evaluations planned to investigate the effect of tall forest canopies on surface wind predictions. Analyses of observations from the isolated mountain and steep river canyon sites indicate that operational weather model (i.e., with numerical grid resolutions of around 4 km or larger) wind predictions are not likely to be good predictors of local near-surface winds (i.e., at sub-grid scales) in complex terrain. Under periods of weak synoptic forcing, surface winds tended to be decoupled from large-scale flows, and under periods of strong synoptic forcing, variability in surface winds was sufficiently large due to terrain-induced mechanical effects that a large-scale mean flow would not be representative of surface winds at most locations on or within the terrain feature. These findings are reported in a manuscript titled “High Resolution Observations of the Near-Surface Wind Field over an Isolated Mountain and in a Steep River Canyon” submitted for publication in Atmospheric Chemistry and Physics. Links to the observed data from this effort as well as an online interface to query, visualize, summarize, and download subsets of the data are available at: http://www.firemodels.org/index.php/windninja-introduction/windninja-publications. Findings from the model evaluations work indicate that using WindNinja to downscale from numerical weather prediction (NWP) model winds can, in some cases, improve the accuracy of surface wind forecasts in complex terrain. Predictions of surface wind speeds and directions improved with downscaling via WindNinja when flow features induced by large scale effects were adequately captured by the NWP model used to initialize WindNinja. This suggests that WindNinja could be incorporated into current fire forecast methods to provide better short-term forecasts for fire management operations. These findings are reported in a manuscript titled “Downscaling Surface Wind Predictions from Numerical Weather Prediction Models in Complex Terrain with a Mass-consistent Wind Model” that will be submitted to the Journal of Applied Meteorology and Climatology later this spring

Effectiveness of post-fire soil erosion mitigation treatments: a systematic review and meta-analysis

Wildfires are known to be one of the main causes of soil erosion and land degradation, and their impacts on ecosystems and society are expected to increase in the future due to changes in climate and land use. It is therefore vital to mitigate the increased hydrological and erosive response after wildfires to maintain the sustainability of ecosystems and protect the values at risk downstream from the fire-affected areas. Soil erosion mitigation treatments have been widely applied after wildfires but assessment of their effectiveness has been limited to local and regional-scale studies, whose conclusions may depend heavily on site-specific conditions. To overcome this limitation, a meta-analysis approach was applied to investigations of post-wildfire soil erosion mitigation treatments published in peer-reviewed journals. A meta-analysis database was compiled that consisted of 53 and 222 pairs of treated/untreated observations on post-fire runoff and erosion, respectively, extracted from 34 publications indexed in Scopus. The overall effectiveness of mitigation treatments, expressed as the quantitative metric ‘effect size’, was determined for both the runoff and erosion observations, and further analyzed for four different types of treatments (cover-based, barriers, seeding, and chemical treatments). The erosion observations involving cover-based treatments were analyzed for differences in effectiveness between 3 different types of mulch materials (straw, wood-based, and hydromulch) as well as between different application rates of straw and wood materials. Finally, the erosion observations were also analyzed for the overall effectiveness of post-fire year, burn severity, rainfall amount and erosivity, and ground cover. The meta-analysis results show that all four types of treatments significantly reduced post-fire soil erosion, but that only the cover and barrier treatments significantly reduced post-fire runoff. From the three different cover treatments, straw and wood mulches were significantly more effective in mitigating erosion than hydromulch. In addition, the effectiveness of both straw and wood mulches depended on their application rates. Straw mulching was less effective at rates below than above 200 g m−2, while mulching with wood materials at high rates (1300 to 1750 g m−2) produced more variable outcomes than lower rates. Results also suggest that the overall effectiveness of the treatments was greatest shortly after fire, in severely burned sites, providing or promoting the development of ground cover over 70%, and that it increased with increasing rainfall erosivity. It can be concluded that, in overall terms, the application of the studied post-fire erosion mitigation treatments represented a better choice than doing nothing, especially in sites where erosion is high. However, the meta-analysis highlights under-representation of studies on this topic outside of the USA, Spain and Portugal. It was also observed that most of the studies were conducted at hillslope scale and tested mulching (namely straw, wood and hydromulch) and/or barriers, while larger scales and other treatments were scarcely addressed. Further efforts need to be made in testing, from field and modeling studies, combinations of existing and/or emerging erosion mitigation treatments to ensure that the most adequate measures are applied after fires.publishe

Direct Detection of Products from the Pyrolysis of 2-Phenethyl Phenyl Ether

The pyrolysis of 2-phenethyl phenyl ether (PPE, C_6H_5C_2H_4OC_6H_5) in a hyperthermal nozzle (300-1350 °C) was studied to determine the importance of concerted and homolytic unimolecular decomposition pathways. Short residence times (<100 μs) and low concentrations in this reactor allowed the direct detection of the initial reaction products from thermolysis. Reactants, radicals, and most products were detected with photoionization (10.5 eV) time-of-flight mass spectrometry (PIMS). Detection of phenoxy radical, cyclopentadienyl radical, benzyl radical, and benzene suggest the formation of product by the homolytic scission of the C_6H_5C_2H_4-OC_6H_5 and C_6H_5CH_2-CH_2OC_6H_5 bonds. The detection of phenol and styrene suggests decomposition by a concerted reaction mechanism. Phenyl ethyl ether (PEE, C_6H_5OC_2H_5) pyrolysis was also studied using PIMS and using cryogenic matrix-isolated infrared spectroscopy (matrix-IR). The results for PEE also indicate the presence of both homolytic bond breaking and concerted decomposition reactions. Quantum mechanical calculations using CBS-QB3 were conducted, and the results were used with transition state theory (TST) to estimate the rate constants for the different reaction pathways. The results are consistent with the experimental measurements and suggest that the concerted retro-ene and Maccoll reactions are dominant at low temperatures (below 1000 °C), whereas the contribution of the C_6H_5C_2H_4-OC_6H_5 homolytic bond scission reaction increases at higher temperatures (above 1000 °C)

Experimental Line Parameters of the b^(1)Σ^(+)_g ← X^(3)Σ^(-)_g Band of Oxygen Isotopologues at 760 nm Using Frequency-Stabilized Cavity Ring-Down Spectroscopy

Positions, intensities, self-broadened widths, and collisional narrowing coefficients of the oxygen isotopologues ^(16)O^(18)O, ^(16)O^(17)O, ^(17)O^(18)O, and ^(18)O^(18)O have been measured for the b^(1)Σg + ← X^(3)Σg − (0,0) band using frequency-stabilized cavity ring-down spectroscopy. Line positions of 156 P-branch transitions were referenced against the hyperfine components of the ^(39)K D_1 (4s ^(2)S_(1/2) → 4p ^(2)P_(1/2)) and D_2 (4s ^(2)S_(1/2) → 4p ^(2)P_(3/2)) transitions, yielding precisions of ~0.00005 cm^(−1) and absolute accuracies of 0.00030 cm^(−1) or better. New excited b^(1)Σg + state molecular constants are reported for all four isotopologues. The measured line intensities of the ^(16)O^(18)O isotopologue are within 2% of the values currently assumed in molecular databases. However, the line intensities of the ^(16)O^(17)O isotopologue show a systematic, J-dependent offset between our results and the databases. Self-broadening half-widths for the various isotopologues are internally consistent to within 2%. This is the first comprehensive study of the line intensities and shapes for the ^(17)O^(18)O or ^(18)O_2 isotopologues of the b^(1)Σg + ← X^(3)Σg − (0,0) band of O_2. The ^(16)O_2, ^(16)O^(18)O, and ^(16)O^(17)O line parameters for the oxygen A-band have been extensively revised in the HITRAN 2008 database using results from the present study

Hydrologic and Erosion Responses to Wildfire Along the Rangeland-Xeric Forest Continuum in the Western US: A Review and Model of Hydrologic Vulnerability

The recent increase in wildfire activity across the rangeland–xeric forest continuum in the western United States has landscape-scale consequences in terms of runoff and erosion. Concomitant cheatgrass (Bromus tectorum L.) invasions, plant community transitions and a warming climate in recent decades along grassland–shrubland–woodland–xeric forest transitions have promoted frequent and large wildfires, and continuance of the trend appears likely if warming climate conditions prevail. These changes potentially increase overall hydrologic vulnerability by spatially and temporally increasing soil exposure to runoff and erosion processes. Plot and hillslope-scale studies demonstrate burning may increase event runoff or erosion by factors of 2–40 over small-plot scales and more than 100-fold over large-plot to hillslope scales. Reports of flooding and debris flow events from rangelands and xeric forests following burning show the potential risk to natural resources, property, infrastructure and human life. We present a conceptual model for evaluating post-fire hydrologic vulnerability and risk. We suggest that post-fire risk assessment of potential hydrologic hazards should adopt a probability-based approach that considers varying site susceptibility in conjunction with a range of potential storms and that determines the hydrologic response magnitudes likely to affect values-at-risk. Our review suggests that improved risk assessment requires better understanding in several key areas including quantification of interactions between varying storm intensities and measures of site susceptibility, the varying effects of soil water repellency, and the spatial scaling of post-fire hydrologic response across rangeland–xeric forest plant communities

Modeling Marsh‐Forest Boundary Transgression in Response to Storms and Sea‐Level Rise

The lateral extent and vertical stability of salt marshes experiencing rising sea levels depend on interacting drivers and feedbacks with potential for nonlinear behaviors. A two‐dimensional transect model was developed to examine changes in marsh and upland forest lateral extent and to explore controls on marsh inland transgression. Model behavior demonstrates limited and abrupt forest retreat with long‐term upland boundary migration rates controlled by slope, sea‐level rise (SLR), high water events, and biotic‐abiotic interactions. For low to moderate upland slopes the landward marsh edge is controlled by the interaction of these inundation events and forest recovery resulting in punctuated transgressive events. As SLR rates increase, the importance of the timing and frequency of water‐level deviations diminishes, and migration rates revert back to a slope‐SLR‐dominated process