A growing body of research has shown that rain-on-snow (ROS) events can have adverse impacts on high-latitude ungulate populations. When rain freezes in the snowpack, it forms ice that blocks access to winter forage and, in extreme cases, contributes to mass die-offs. Research into the atmospheric conditions that cause ROS have shown a relation to anomalously southerly winds and warm, moist air associated with the passage of extratropical cyclones. However, these conditions are common for many winter precipitation events, not just ROS. This study uses the MERRA2 atmospheric reanalysis to differentiate ROS events in Alaska from precipitation events in which only snow falls on a preexisting snowpack (snow-on-snow, or SOS). Although ROS-producing storms are no stronger than SOS-producing storms, for much of Alaska (the interior, southwest, and south central), the tracks of ROS-producing storms tend to be farther north and west than SOS-producing storms. Sea-level pressure in the eastern Gulf of Alaska is significantly higher during ROS than SOS, as well as 72 hours prior to storm events. This suggests that blocking highs in the Gulf of Alaska may help encourage rainfall (and therefore rain-on-snow events) by: 1) diverting storms to the northwest, which places more of Alaska under the influence of southerly flow and 2) strengthening that southerly flow by increasing the pressure gradients on the southeast side of storms. Both mechanisms might contribute to the significantly higher 2-m air temperature and total column water vapor observed for ROS versus SOS. The role of blocking highs may also provide a source of predictability for ROS events in parts of Alaska.

Vehicle-based methane-sensing systems are gaining popularity as tools for monitoring site-level methane emissions from oil and gas (O&G) sites. To measure emissions, vehicles equipped with methane sensors intersect plumes along roads downwind of target sites and acquire measurements in static (parked) or mobile modes. The downwind distance between the emissions source and the measurement location is one of several factors that must be considered in planning these types of surveys. Here we present a method to estimate the suitability of O&G facilities for vehicle-based measurements using downwind distances recommended in OTM 33A and the tracer technique. We present two types of analyses: (1) a historical analysis using weather reanalysis data and (2) an operational analysis using forecast data. The method uses modeled wind direction and geospatial data to identify O&G facilities that have roads between 20 and 200 m downwind for OTM 33A and between 500 m and 3000 m downwind for the tracer technique. We apply the method to O&G facilities in Alberta that will soon require annual or triannual LDAR surveys. For the historical analysis we use ERA-Interim wind data and calculate the vectorial average (resultant) of modeled winds for the period 2009-2018. Of the 35047 O&G facilities examined, we find that 7% are, on average, suitable for OTM 33A and 69% are, on average, suitable for the tracer technique, based solely on downwind distance. We surmise that other factors like landcover, weather conditions (e.g., stability), and topography would likely reduce the candidate pool from these estimates. We demonstrate the operational utility of the method by examining a subset of 100 O&G facilities in southern Alberta and using forecast wind direction from the Canadian High Resolution Deterministic Prediction System (HRDPS), which has a 2.5 km grid spacing. We propose that the method can be used as a screening tool to estimate site suitability for static vehicle-based surveys and that it will likely translate to mobile surveys once the effect of downwind distance is clarified. Other factors can be incorporated in the method once test results are available.

The coupling of CO2 emissions and tectonic activity in active plate margins is becoming increasingly prominent, as remote sensing techniques make this relationship readily observable on a global scale. However, direct observations of the processes that link emissions and seismicity are lacking. This study documents observations from the deep part of an ancient continental rift system, now exposed at the Earth’s surface. We demonstrate how volatiles and preexisting magma chamber structures affect the influx of new magma and how magma induced deformation plays a key role during the shift from initial plume related magmatism to rifting, by altering the rock rheology and facilitating strain localization. The outcrops are comprised of ultramafic cumulates, intersected by mafic dykes. The ultramafic cumulates consist of three units: the central series, upper layered series and the lower layered series, with the central series being the youngest and partly replacing the upper and lower layered series. The dykes intersecting the upper layered series are partially remolten and replaced by the influx of the central series cumulates. This is especially evident in mafic dykes in wherlitic cumulates of the upper layered series. Younger melts of the central series used the contact between the dykes and host wehrlite as a pathway. The heating caused partial melting of the mafic dyke, which acted as a lubricant during deformation. In addition to the lubrication effect of the melt, volatiles within the mafic dykes, including CO2 react with the mafic minerals within the host ultramafic rocks, leading to fracturing and brecciation, and locally followed by diffusion creep in the finer-grained material. PT-estimates indicate that this brecciation took place under lower crustal/upper mantle conditions. Hence, conditions of deformation can shift from low strain rate plastic creep to ultrafast localized seismic creep in a short time due to local structural and compositional inhomogeneities.

Smoke influence in urban areas is relatively easy to detect at high concentrations, but more challenging to detect at low concentrations. For this reason, we have evaluated an approach using thermal desorption gas chromatography mass spectrometry (TD-GC-MS) to detect volatile organic compounds (VOCs) in particular oxygenated VOCs in urban areas. The goal of this work is to develop a method that can reliably quantify smoke tracers in an urban environment at relatively low cost and complexity. We present here the development and validation of a double-bedded thermal desorption tube with an auto sampler to collect continuous samples of VOCs. To evaluate the method performance, we have tested stability during storage, interferences (e.g., water and O3), and reproducibility for six VOCs, namely, acetonitrile, acetone, pentane, iso-pentane, benzene, and toluene. The results demonstrate that these can be quantified reproducibly with an error ≤ 20% between the collection and analysis with a storage time of up to 21 days. For acetone, similar results were obtained until day 14. Calibration experiments performed over a dynamic range of 10–150 ng loaded over thermal desorption tubes at different relative humidity showed excellent linearity (r2 ≥ 0.91). At this time, we are utilizing this method during the summer 2019 FIREX-AQ intensive experiment at the Boise ground site in Idaho. These results will be presented along with the quality control data.

In principle, a goal of any regional seismic network (RSN) is simple - detect and review seismicity in the network’s region of interest. Vigorous aftershock sequences however present a unique challenge to an RSN’s mission in that they can overwhelm automated real-time and analyst-driven post-processing systems. This inundation with seismicity can the lead to earthquake catalogs that are incomplete and erroneous in the area around the aftershock sequence. In response to this challenge, this abstract explores integrating machine learning as a tool to expedite the University of Utah Seismogram Station’s (UUSS)’s response to the September, 2017 Soda Springs event in southeast Idaho. In the months following the event the UUSS was able to locate over 1000 aftershocks and was catalog complete to approximately 2.5 M_L. Owing to the fact that a temporary deployment of 6 six-channel and 2 strong-motion instruments were deployed to the area shortly after the event, it is anticipated that many more high-quality locations can be obtained without resorting to template matching. Therefore, it is our goal to attempt to recover the existing UUSS catalog with machine learning enabled workflows that can produce analyst-grade picks for location and subsequent magnitude estimation. Should this be successful then the anticipated consequence is that analysts can quickly screen and approve more events and by extension lower the network’s magnitude completeness during the aftershock sequence.

In the framework of EGS, using hydraulic stimulation increases pore pressure into the existing fracture networks and can be responsible for slip reactivations. In order to predict the seismic or aseismic character of these slips, it is important to determine the influence of the gouge characteristics on the slip behaviour. Lab or in-situ testing can be very helpful, but experience has shown that it is complicated to install local sensors inside a mechanical contact and that some data remains impossible to obtain. In this study, we are focusing on the physics of the contact inside a granular gouge to understand the mechanisms of slip triggering by using numerical modelling. We implement a 2D granular fault gouge with Discrete Element Modelling (DEM). The model involves two rough surfaces representing the rock walls separated by a granular gouge with realistic angular particles created by the wear of previous slips. A displacement-driven model with dry contact is primarily studied to observe the peak of static friction (shape, slope or duration). In order to spotlight the aseismic and seismic patterns, a second model is carried out to add the stiffness of the rocks (or loading apparatus). Dedicated post processing tools are also used in order to analyse the spatial distribution of the solid fraction and the force chains patterns bringing a new understanding of physics from a granular point of view. Representing realistic morphology of particles (angular shapes) brings an additional level of control with respect to most of the simulations reported in the literature using circular grains. Angular grains lead to higher friction coefficients with different global behaviours. The initial solid fraction of the gouge appears to be a good indicator of the friction peak we have at a slip triggering (Fig.). The more compacted the gouge is, the more effort is needed to disturb the initial grains assembly and to reach a steady state regime. With fractal size distribution, we have also studied the mechanical contribution of small particles in the media. Friction coefficient results let us conclude that the presence or not of very small particles is not as influent as the initial solid fraction of the gouge. Finally, adding a stiffness on the upper rock wall provides information on the transition from stable sliding to slow-slip/stick-slip behaviour.

When Apollo returned the first moonrocks, a major surprise was that the lunar highlands are built of a single mineral - feldspar. Feldspar crystals floating to the top of a moon-magma ocean can explain this composition. If accepted as a key early stage in lunar evolution, it is a logical leap to infer that Earth must have had a similar – or larger – magma ocean during its early evolution. (The gravitational impact energy per unit mass that is released during a planetesimal’s accretion scales as GM/R.) The nagging problem with the inference that Earth passed through an early magma-ocean stage is that the oldest rocks on Earth show no direct signs of a magma ocean. Instead the petrology of the oldest preserved Earth rocks shows clear evidence that repeated events of small to medium degrees of partial melting and melt extraction, as opposed to pervasive fractional crystallization, has been the modus operandi of terrestrial differentiation. The big difficulty is how to effectively ‘remix’ the products of an early terrestrial magma ocean back into the quasi-uniform ‘primordial’ pyrolite/peridotite silicate lithology from which oceanic and continental crust are thought to have evolved by partial melting events. Here I propose that a partially molten silicate body is actually highly resistant to the formation of a magma ocean. Jing and Karato (2012)’s experiments imply that a silicate melt should absorb much more impact shock-energy than either a silicate solid or an iron solid/melt. In this case, impact energy will be heterogeneously added into the growing proto-Earth, with silicate partial melts being shock-compression-heated to their vaporization temperature before their surrounding silicate solids heat to their melting point. The growing partially molten planetary surface will tend to ‘explode’ during impact events, with each impact-induced-explosion using a relatively small mass of vaporized silicate partial melt to fragment and rework much larger masses of cold, shock-fractured overlying ‘lithosphere’. This explosive-armour-like mode for silicate planetary accretion will strongly resist the magma ocean-mode of planetary differentiation. A magma ocean would only tend to form in the planetary body created from the accreting debris ring of a giant impact event, a Moon.

My laboratory is developing an accelerometer. However, if you do not install the dedicated software, you can not browse the data. In addition, since it is necessary to go to the site on a semi-annual basis and collect data due to capacity problems, the current operation is burdened. In order to solve these problems, we devised WebGL that enables high-speed drawing when processing a large amount of data such as Big Data, and a Web application that uses server that can transmit, save, and download acquired data. In this application, an accelerometer and a raspberry pie are connected, and the raspberry pie receives data obtained from the accelerometer and sends the data to a server installed in a laboratory by SCP file transfer at regular intervals. These data specify the location and date from the client side through the Internet browser, download the data using the download function of the browser, read this data on the application and draw the waveform. The data obtained from the accelerometer in the development to date is converted into a CSV file and transferred to the server. These data can be downloaded and displayed on the web application. For the google map displayed on the right side of the screen, it is to make the application more useful by registering the location where the accelerometer was set in the future.

Canary Islands constitute an active volcanic archipelago. From the time immediately before the Castilian conquest of the islands, 17 volcanic eruptions have occurred: 2 prehispanic and 15 historical, some of them with multiple eruptive vents, affecting the islands of Lanzarote, Tenerife, La Palma and El Hierro. In order to carry out the inventory of geosites for the Canary Islands at a regional scale, it has been applied a methodology consisting of two sequential phases: the first one address the selection of geosites that will be part of the inventory, and the second one deals with the characterization and assessment of the selected geosites. In this methodology, geosites are selected within geological frameworks previously established given their regional significance for Canary Islands. With this aim, 12 geological frameworks representative of the geodiversity of Canary Islands have been identified, which include the essential elements, processes and morphologies of the Canarian geology, covering all stages of construction of the islands as well their geological evolution, including processes, morphologies, fossils and deposits associated both to the volcanism and the external geological agents. The selection of geosites is then constrained and facilitated by its representativeness within each geological framework. One of these 12 geological frameworks corresponds to “Historical and prehistorical volcanism”. The scarce number of volcanic eruptions, their low frequency and their general characteristics –fissure mafic eruptions, low VEI and strombolian eruptive styles- determine an apparent geological homogeneity. Nevertheless, the high variety of processes, morphologies and deposits associated to this framework, their good conservation status, as well as the information from the historical chronicles, have permitted to identify 19 geosites of high scientific value. They highlight the existence of eruptive styles ranging from hawaian to vulcanian, with short phases of water-magma contact, quiet emissions of water or in geysers, phreatomagmatic explosions, etc. These geosites constitute a unique and representative record of the volcanology, geomorphology, tectonics and petrology characterizing the most recent mafic volcanism of the Canarian archipelago.

New Caledonia’s Ni deposits account for ~ 8.2% of the world’s production of mined nickel, with a major smelting facility located in the country’s capital city of Nouméa (population 100,000). There are emerging concerns relating to contamination of human and natural ecosystems from dust and soil contamination from mineral processing emissions, which started the late 19th century. There is widespread reuse of Ni smelter slag in the city for multiple uses (e.g. building aggregate, erosion control, added to soil and surface as ‘gravel’) in the city, which contains up to 2% Cr. This study provides the first integrated environmental analysis of the impact of the smelter and associated anthropogenic trace element contamination of Noumea’s natural and human environments. To assess the impacts from smelting, hundreds of trace element data points were collected across Nouméa in a variety of matrices. These include natural rocks and deep soils, top soils, deposited dusts, residential garden soils, indoor vacuum dusts, honey bees and honey produced within the city’s urban environment. Rocks, soils and exterior and interior vacuum dusts were analysed for their trace element concentrations using X-ray fluorescence at < 100 locations within a 3 km radius of Nouméa’s Ni smelter. Samples of bees (live and dead), honey, soil and deposited dust were collected at 15 beehive locations across the Noumea area to ascertain if and what contaminants are being remobilized in dust, contaminating both food and ecological systems. Natural/background values were assessed using two bee hive locations, distant from the smelter, along with analysis of rocks and sub-surface soils from the main geological strata present in the city. Preliminary environmental data show that anthropogenic contaminants Cr, Ni, Pb and S exceed natural values by up to 8, 2.5, 10 and 15 times in different matrices. Analysis shows that CrVI is present in the slag and surface dusts (x̅ total Cr in deposited dust = 450 µg/m2) and that more than 60% of Ni dust loadings are > 1000 µg/m2 (x̅ Ni in dust = 2,400 µg/m2). The presentation will detail trace element concentrations in live and dead bees and corresponding honey samples and evaluate the data against corresponding levels measured in the adjoining environment to assess the remobilization and recycling of anthropogenic contaminants.

An intense tropical cyclone, Typhoon Jebi, landed the central part of Japan in September 2018 and caused severe damages due to strong winds. Typhoon Jebi obtained the lifetime minimum central pressure of 915 hPa and took a track very similar to past disastrous typhoons: Typhoon Nancy (1961) and Muroto Typhoon (1934). In Osaka City, the 1st, 2nd, and 3rd highest record of instantaneous wind speeds are 60.0 m/s in September 1934, 50.6 m/s in September 1961, and 47.4 m/s in September 2018, respectively, suggesting that a typhoon has been the most threatening windstorm in the area. Buildings and structures in urban areas are known to affect significantly the magnitude of wind gustiness. Because of the growing urbanization globally, quantification of turbulent winds in densely-built, urban districts is important to understand the underlying risks of wind damages. We investigate the influences of densely built urban environments on the occurrence of wind gusts in urban districts of Osaka and Kyoto City during the landfall of Typhoon Jebi by merging mesoscale meteorological and building-resolving large-eddy simulations (LES). By explicitly representing realistic buildings and structures in LES, this study examines complex/complicated characteristics of winds within the densely built urban environment. With the successful reproduction of the track and intensity of the typhoon in meteorological simulations, the simulated winds at the boundary-layer top of the LES model are used to quantify the wind gusts in the urban district. The maximum wind gust in the analysis area of Osaka is around 60-70 m/s, which is comparable to the wind speed at the height of about 300 m. Such wind gusts are generated by instantaneous downward momentum transfer in areas of a cluster of buildings with variable heights. Instantaneous wind gusts are further examined in terms of building density and are found to be strongest when the building packing density is moderate. The results suggest that the risks of wind damages would be maximized in urban districts where the building height is inhomogeneous and the packing density is moderate.

Defining a baseline for the frequency of off-normal occurrences at underground natural gas storage facilities is critical to maintaining safe operation and to the development of appropriate risk management plans and regulatory approaches. Currently used frequency-estimation methods are broadened to include critical factors of cause, severity, and uncertainty that contribute to risk. A Bayesian probabilistic analysis characterizes the aleatoric historical occurrence frequencies given imperfect sampling. Occurrence frequencies for the three main storage facility types in the United States (depleted oil-and-gas field storage, aquifer storage, solution-mined salt cavern storage) are generally on the order of 3 to 9 x 10–2 occurrences, of all causes (surface, well integrity, subsurface integrity) and severities (nuisance, serious, catastrophic), per facility-year. Loss of well integrity is associated with many, but not all, occurrences either within the subsurface or from there up to the surface. The probability of one serious or catastrophic leakage occurrence to the ground surface within the next 10 years, assuming constant number of facilities, is approximately 0.1–0.3% for any facility type. Storage operators and industry regulators can use occurrence frequencies, their associated probabilities and uncertainties, and forecasts for severity magnitudes to better prioritize resources, establish a baseline against which progress toward achieving a reduction target is measured, and develop more effective mitigation/monitoring/reduction programs in a risk management plan.

The dithiothreitol (DTT) assay is widely used to characterize the Oxidation Potential (OP) of atmospheric particulate matter (PM), which can cause adverse effects on human health. However, it’s under debate which chemical species determines the consumption rate of DTT. During January and April 2018, we measured the improved DTT assay of daily PM2.5 samples collected in Guangzhou, China with complimentary measurements of water-soluble ions, organic/elemental carbon (OC/EC) and metal elements. The average sampled air volume normalized consumption rate of DTT (DTTv) was 4.67 ±1.06 and 4.45 ± 1.02 nmol min-1 m-3, in January and April, respectively while the average PM2.5 mass normalized consumption rate of DTT (DTTm) was 13.47 ± 3.86 and 14.66 ± 4.49 pmol min-1 μg-1. Good correlations were found between DTTv and concentration of PM2.5, OC, and EC while no correlation was found between DTTm and concentrations of water-soluble ions, OC, EC or metal element, which is consistent with most early observations. We also evaluated the contribution of soluble metals to DTT assay by addition of EDTA, a strong metal chelator. We found that nearly 90% of DTTv and DTTm were reduced by EDTA, suggesting a dominant role of soluble metals in determining the response of DTT to ambient PM2.5. Based on responses of DTT to soluble metals in literature, we found that Cu(II) and Mn(II) are the major contributors to OP of PM2.5 in Guangzhou. The correlation coefficient between DTTm and OC shows a clear increase after addition of EDTA, implying that the response of DTT to quinones is not strongly suppressed by EDTA.

Changing irrigation water demand (IWD) and supply (IWS) patterns (size and time) under increased climate variability and socio-economic development is significantly effecting the water and food production in the densely populated South Asia (SA). Considering food security paradigm of SA, where rice and wheat are major staple and water-intensive crops, this study aims to investigate the linkages in IWD by crops and IWS by sources (surface and groundwater) using integrated climate and socio-economic projections. The novel aspect of this study is to explore IWD and IWS pattern shifts during critical crop growth stages (CW’s), which is previously less studied with no remarkable research evidence for IGB region. Quantification of shifts in IWD and IWS patterns in future is crucial for long-term integrated water resources and agricultural planning. For this, LPJmL crop-water model is forced with an ensemble of eight state of the art downscaled GCM at 5 arc-min resolution. To assess the combined impacts of climate and socio-economic changes, RCP-SSP framework is used. Our statistical analysis results show that IWD is higher in vegetative stage (CW1) than the reproductive stage (CW2) during both Rabi and Kharif cropping seasons. Water demand is decreasing in future for wheat while increasing for rice. IWS is decreasing substantially from surface while increasing largely from groundwater resources during Rabi. Though, IWS during kharif season is increasing largely from both surface and groundwater resources. There is mismatch in demand and supply as evident from the results suggesting 10 days early wheat planting reduces IWD by 8.0% in F1, 18.7% in F2 and 28.4% in F3 during CW1 with a decrease of 7%, 30 % and 62.56% during F1, F2 and F3 in CW2. Increased IWS with larger contribution from groundwater resources is projected for both crops in future. Water gap between demand and supply during both CW’s in future is increasing for Rabi and Kharif suggesting 10 days early planting of wheat while 20 days delay in kharif planting. Estimation of IWS by sources helped in assessing shifts in percent (%) dependency of water supply from different sources. Moreover, Spatio-temporal mismatch between water demand and supply help exploring geospatially driven water gap trends consequently, highlighting water stress hotspots during CW’s in future.

Results of laboratory experimental study of the hydraulic fracture initiation, its propagation and closing, re-fracturing, the fluid pore pressure variations and related acoustic emission (AE) are considered. The experimental setup differs from common equipment designed for testing cores or cubic samples; it is designed for work with samples of disk form with diameter 430 mm and height 66 mm, which allows us to measure the pore pressure distributions along the sample boundary together with passive and active acoustic emission measurements (Fig.1). The experiments were conducted with artificial porous saturated samples made from gypsum-cement mixture in agreement with simulation criteria. The samples were created by filling the pressure chamber with the gypsum-cement-water mixture. After drying, the samples were saturated by gypsum water solution and loaded by three-axial stresses. To produce the fracture, mineral oil was injected with the constant rate 0.3 sm3/sec through the cased borehole. A set of experiments was conducted, in which the main stress axis orientation was changed after the first hydraulic fracture creation. Registration of the change in the amplitude of the waves passing through the fracture allowed to determine the fracture formations, its filling with fluid, the increase in the fracture opening as the injection continued, and the fracture closing after the injection was stopped. It was found that the influence of the fluid pore pressure diffusion from the point of injection is of great significance: the fracturing pressure was several megapascals higher than it should be expected. The fracture closing pressure also occurred to be higher in comparison with the case, when the pressure diffusion is neglected. It was obtained, that the AE source positions are closely related with the fracture position. It is remarkable, that we did not registered any AE outside the fracture. Comparison that fact with the results of the pore pressure measurements allows to suggest, that the pressure increase due to the viscous fluid injection is not enough to induce AE pulses at some distance from the borehole and the fracture. When the injection fluid has the same viscosity as the fluid saturating the sample, the pressure increase is sufficient to induce acoustic emission corresponding to the pore pressure increase.

Accurate characterization of hydraulic and poroelastic rock properties is crucial for successful management of groundwater, petroleum resources and subsurface contaminant remediation. The oscillating pore pressure method is a popular laboratory technique for permeability and specic storage measurements of rock samples. We present an improvement of the oscillating pore pressure method by simultaneously measuring hydraulic and poroelastic properties of rocks. Measurements were carried out for four conventional reservoir rock quality samples at oscillation frequencies of 0.025–1 Hz and effective pressures of 3.5–62 MPa. Interpreted permeability values decreased with increasing effective pressure and increased sharply above a frequency range of 0.3–0.4 Hz. We established that hydraulically measured storage capacities are overestimated by an order of magnitude when compared to elastically derived ones. Biot coecient was estimated both from pore pressure and strain measurements, and comparison of two data sets reveals high uncertainty of the hydraulic specic storage measurements. We documented grain crushing and pore collapse in a dolostone sample, observed as a permanent and drastic decrease of permeability and bulk modulus. We validated our method by detecting irreversible microstructural changes independently by hydraulic, elastic, X-ray microtomography ( CT) and nuclear magnetic resonance (NMR) measurements. We further developed a novel data processing approach that utilizes a broad, multifrequency range of data which are inverted for permeability. We re- process published data and demonstrate that our methodology outperforms traditional data reduction techniques, as our inversion results show a better t to pressure trends. To better understand the effect of frequency on phase and amplitude data and to verify our inversion approach we numerically simulate oscillating pore pressure experiments. We document a strong deviation of experimentally obtained phase data starting at 0.3 Hz oscillation frequency. Our method can be used for robust determination of permeability and rapid prediction of experimental results using numerical simulation, ultimately improving experimental permeability measurements.

Carbon dioxide is a greenhouse gas that has a strong absorption in the 4.2– 4.3 micrometers region of the infrared spectrum. Consequently, non-dispersive infrared (NDIR) spectroscopy using interference optical filters tuned in this spectral band can be utilized to provide reliable, high resolution and fast response measurements of atmospheric CO2 concentrations. As part of eddy covariance systems, open-path gas analyzers based on this principle are widely used in remote locations around the world because of their low-power consumption, fast frequency response, and ease of operation. One of the challenges of the open-path design is that the in-situ optical beam is exposed to the rapid fluctuations in ambient temperature. Besides gas composition and pressure being the two major spectroscopic line broadening mechanisms that affect the absorption of infrared light, air temperature also can influence the broadened half-width and the intensity of the spectral lines. Consequently, the fast temperature fluctuations of the air parcels in the optical path of such a sensor can produce changes in the amount of absorbed light and cause errors in the gas concentration measurement that can propagate into the flux calculations. The temperature dependence of the infrared absorption has not been quantified in the context of the CO2 NDIR gas analyzer methodology. The study will evaluate the temperature effects on absorption spectra of CO2-air-mixtures across the 4.2–4.3 micrometers infrared active region, typically used by NDIR gas analyzers. Infrared spectra will be modeled line-by-line from spectral-line parameters obtained from the high-resolution transmission molecular spectroscopic database (HITRAN). HITRAN-predicted molecular cross sections, the product of component spectral line intensity and spectral line shape at different wavelength, will be used to generate absorption spectra of CO2 air mixtures at ambient pressure using different concentrations and temperatures. The temperature dependence of CO2 absorption will be inferred from the integrated area under the absorptivity curve. Results interpreted in the context of the Beer-Lambert law will further characterize the temperature related spectroscopic effects on CO2 concentration calculations.

Department of Water Resources (DWR), in partnership with the Merced Irrigation District (MID), is conducting a reconnaissance level study to assess the potential of implementing Flood-MAR in the Merced River watershed within the San Joaquin Valley. One aspect of the Flood-MAR study focuses on reservoir operations using synthetic hydrology generated based on the Paleoclimate (Tree-Ring) Study methodology. The MID HEC-ResSim model was calibrated to simulate water supply and flood control operations over the water year. The model was modified to estimate water available for Flood-MAR based on flow at a downstream location, conveyance capacity and groundwater recharge capacity. Results include changes in storage at Lake McClure, flow in Merced River, water supply deliveries, and Flood-MAR deliveries due to Flood-MAR implementation. The study also assesses the vulnerability of reservoir operations due to changing hydrology by evaluating the effects of climate change on flood management, water supply reliability, and drought resiliency. The flood management aspect of the vulnerability analysis assesses change in peak flow, flow volume, and duration of flooding events. The water supply reliability assesses change in carryover storage and deliveries for irrigation demands. The drought resiliency assessment includes change in magnitude and duration of the historical and synthetic drought events. The results of the reservoir operations vulnerability analysis will be used to determine the multiple benefits of Flood-MAR implementation.