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At least 397 records · Page 22Linked to original sources
USGS2014

Estimating the volcanic emission rate and atmospheric lifetime of SO 2 from space: a case study for Kīlauea volcano, Hawai'i

We present an analysis of SO 2 column densities derived from GOME-2 satellite measurements for the Kīlauea volcano (Hawai`i) for 2007–2012. During a period of enhanced degassing activity in March–November 2008, monthly mean SO 2 emission rates and effective SO 2 lifetimes are determined simultaneously from the observed downwind plume evolution and meteorological wind fields, without further model input. Kīlauea is particularly suited for quantitative investigations from satellite observations owing to the absence of interfering sources, the clearly defined downwind plumes caused by steady trade winds, and generally low cloud fractions. For March–November 2008, the effective SO 2 lifetime is 1–2 days, and Kīlauea SO 2 emission rates are 9–21 kt day −1 , which is about 3 times higher than initially reported from ground-based monitoring systems.

Hawaii↗
USGS2017

Links between atmosphere, ocean, and cryosphere from two decades of microseism observations on the Antarctic Peninsula

The lack of landmasses, climatological low pressure, and strong circumpolar westerly winds between the latitudes of 50°S to 65°S produce exceptional storm‐driven wave conditions in the Southern Ocean. This combination makes the Antarctic Peninsula one of Earth's most notable regions of high‐amplitude wave activity and thus, ocean‐swell‐driven microseism noise in both the primary (direct wave‐coastal region interactions) and secondary (direct ocean floor forcing due to interacting wave trains) period bands. Microseism observations are examined across 23 years (1993–2015) from Palmer Station (PMSA), on the west coast of the Antarctic Peninsula, and from East Falkland Island (EFI). These records provide a spatially integrative measure of both Southern Ocean wave amplitudes and the interactions between ocean waves and the solid Earth in the presence of sea ice, which can reduce wave coupling with the continental shelf. We utilize a spatiotemporal correlation‐based approach to illuminate how the distribution of sea ice influences seasonal microseism power. We characterize primary and secondary microseism power due to variations in sea ice and find that primary microseism energy is both more sensitive to sea ice and more capable of propagating across ocean basins than secondary microseism energy. During positive phases of the Southern Annular Mode, sea ice is reduced in the Bellingshausen Sea and overall storm activity in the Drake Passage increases, thus strongly increasing microseism power levels.

Antarctic Penninsula↗
USGS2016

Yosemite Hydroclimate Network: Distributed stream and atmospheric data for the Tuolumne River watershed and surroundings

Regions of complex topography and remote wilderness terrain have spatially varying patterns of temperature and streamflow, but due to inherent difficulties of access, are often very poorly sampled. Here we present a data set of distributed stream stage, streamflow, stream temperature, barometric pressure, and air temperature from the Tuolumne River Watershed in Yosemite National Park, Sierra Nevada, California, USA, for water years 2002–2015, as well as a quality-controlled hourly meteorological forcing time series for use in hydrologic modeling. We also provide snow data and daily inflow to the Hetch Hetchy Reservoir for 1970–2015. This paper describes data collected using low-visibility and low-impact installations for wilderness locations and can be used alone or as a critical supplement to ancillary data sets collected by cooperating agencies, referenced herein. This data set provides a unique opportunity to understand spatial patterns and scaling of hydroclimatic processes in complex terrain and can be used to evaluate downscaling techniques or distributed modeling. The paper also provides an example methodology and lessons learned in conducting hydroclimatic monitoring in remote wilderness.

California↗
USGS2017

Atmospheric deposition of glacial iron in the Gulf of Alaska impacted by the position of the Aleutian Low

Our understanding of glacial flour dust storm delivery of iron to the Gulf of Alaska (GoA) is limited. Here we interpret concurrent time series satellite, meteorological, and aerosol geochemical data from the GoA to examine how interannual variability in regional weather patterns impacts offshore aerosol glacial Fe deposition. In 2011, when a northerly Aleutian Low (AL) was persistent during fall, dust emission was suppressed and highly intermittent due to prevalent wet conditions, low winds, and a deep early season snowpack. Conversely, in 2012, frequent and prolonged fall dust storms and high offshore glacial Fe transport were driven by dry conditions and strong offshore winds generated by persistent strong high pressure over the Alaskan interior and Bering Sea and a southerly AL. Twenty‐five‐fold interannual variability in regional offshore glacial aerosol Fe deposition indicates that glacial dust's impact on GoA nutrient budgets is highly dynamic and particularly sensitive to regional climate forcing.

Geophysical Research Letters↗
USGS2017

Seasonality of stable isotope composition of atmospheric water input at the southern slopes of Mt. Kilimanjaro, Tanzania

To understand the moisture regime at the southern slopes of Mt. Kilimanjaro, we analysed the isotopic variability of oxygen (δ 18 O) and hydrogen (δD) of rainfall, throughfall, and fog from a total of 2,140 samples collected weekly over 2 years at 9 study sites along an elevation transect ranging from 950 to 3,880 m above sea level. Precipitation in the Kilimanjaro tropical rainforests consists of a combination of rainfall, throughfall, and fog. We defined local meteoric water lines for all 3 precipitation types individually and the overall precipitation, δD prec = 7.45 (±0.05) × δ 18 O prec + 13.61 (±0.20), n = 2,140, R 2 = .91, p < .001. We investigated the precipitation-type-specific stable isotope composition and analysed the effects of amount, altitude, and temperature. Aggregated annual mean values revealed isotope composition of rainfall as most depleted and fog water as most enriched in heavy isotopes at the highest elevation research site. We found an altitude effect of δ 18 O rain = −0.11‰ × 100 m −1 , which varied according to precipitation type and season. The relatively weak isotope or altitude gradient may reveal 2 different moisture sources in the research area: (a) local moisture recycling and (b) regional moisture sources. Generally, the seasonality of δ 18 O rain values follows the bimodal rainfall distribution under the influences of south- and north-easterly trade winds. These seasonal patterns of isotopic composition were linked to different regional moisture sources by analysing Hybrid Single Particle Lagrangian Integrated Trajectory backward trajectories. Seasonality of d excess values revealed evidence of enhanced moisture recycling after the onset of the rainy seasons. This comprehensive dataset is essential for further research using stable isotopes as a hydrological tracer of sources of precipitation that contribute to water resources of the Kilimanjaro region.

Mt. Kilimanjaro↗
USGS2006

Midwestern streamflow, precipitation, and atmospheric vorticity influenced by Pacific sea-surface temperatures and total solar-irradiance variations

A solar effect on streamflow in the Midwestern United States is described and supported in a six-step physical connection between total solar irradiance (TSI), tropical sea-surface temperatures (SSTs), extratropical SSTs, jet-stream vorticity, surface-layer vorticity, precipitation, and streamflow. Variations in the correlations among the individual steps indicate that the solar/hydroclimatic mechanism is complex and has a time element (lag) that may not be constant. Correct phasing, supported by consistent spectral peaks between 0.092 and 0.096 cycles per year in all data sets within the mechanism is strong evidence for its existence. A significant correlation exists between total solar irradiance and the 3-year moving average of annual streamflow for Iowa (R = 0.67) and for the Mississippi River at St Louis, Missouri (R = 0.60), during the period 1950-2000. Published in 2005 by John Wiley & Sons, Ltd.

International Journal of Climatology↗
USGS2020

Applications of knowledge and predictions of atmospheric rivers

This chapter reviews how AR research is being applied in real-world situations to address issues of flood planning and emergency intervention. It includes water supply management case studies. Examples comprise five distinct sections that show how AR research is being directly applied to the challenges that water managers, dam operators, crisis-management engineers such as USACE, National Weather Service (NWS) personnel, the media, and others face. These topics include how decision-makers on the ground must iteratively alternate between forecasts and their own field observations, especially in unfolding emergency-response conditions, and the trade-offs necessitated between acting on competing priorities such as flood-risk management and water supply management. Ultimately, almost all AR studies have the potential to directly benefit the public’s need for ongoing water supply as well as for accurate weather forecasts and deployable emergency protocols for natural hazards that necessitate municipal, state, and federal government personnel to collaborate.

Book chapter↗
USGS1988

Atmospheric deposition effects on the chemistry of a stream in Northeastern Georgia

The quantity and quality of precipitation and streamwater were measured from August 1985 through September 1986 in the Brier Creek watershed, a 440-ha drainage in the Southern Blue Ridge Province of northeastern Georgia, to determine stream sensitivity to acidic deposition. Precipitation samples collected at 2 sites had a volume-weighted average pH of 4.40 whereas stream samples collected near the mouth of Brier Creek had a discharge-weighted average pH of 6.70. Computed solute fluxes through the watershed and observed changes in streamwater chemistry during storm flow suggest that cation exchange, mineral weathering, SO 4 2− adsorption by the soil, and groundwater discharge to the stream are probable factors affecting neutralization of precipitation acidity. Net solute fluxes for the watershed indicate that, of the precipitation input, > 99% of the H + , 93% of the NH 4 + and NO 3 − , and 77% of the SO 4 2− were retained. Sources within the watershed yielded base cations, Cl − , and HCO 3 − and accounted for 84, 47, and 100% of the net transport, respectively. Although streamwater SO 4 2− and NO 3 − concentrations increased during stormflow, peak concentrations of these anions were much less than average concentrations in the precipitation. This suggests retention of these solutes occurs even when water residence time is short.

Georgia↗
USGS2010

Atmospheric stability effects on wind fields and scalar mixing within and just above a subalpine forest in sloping terrain

Air temperature T a , specific humidity q , CO 2 mole fraction χ c , and three-dimensional winds were measured in mountainous terrain from five tall towers within a 1 km region encompassing a wide range of canopy densities. The measurements were sorted by a bulk Richardson number Ri b . For stable conditions, we found vertical scalar differences developed over a “transition” region between 0.05 < Ri b < 0.5. For strongly stable conditions ( Ri b > 1), the vertical scalar differences reached a maximum and remained fairly constant with increasing stability. The relationships q and χ c have with Ri b are explained by considering their sources and sinks. For winds, the strong momentum absorption in the upper canopy allows the canopy sublayer to be influenced by pressure gradient forces and terrain effects that lead to complex subcanopy flow patterns. At the dense-canopy sites, soil respiration coupled with wind-sheltering resulted in CO 2 near the ground being 5–7 μmol mol −1 larger than aloft, even with strong above-canopy winds (near-neutral conditions). We found Ri b -binning to be a useful tool for evaluating vertical scalar mixing; however, additional information (e.g., pressure gradients, detailed vegetation/topography, etc.) is needed to fully explain the subcanopy wind patterns. Implications of our results for CO 2 advection over heterogenous, complex terrain are discussed.

Boundary-Layer Meteorology↗
USGS2018

Downscaling future climate change projections over Puerto Rico using a non-hydrostatic atmospheric model

We present results from 20-year “high-resolution” regional climate model simulations of precipitation change for the sub-tropical island of Puerto Rico. The Japanese Meteorological Agency Non-Hydrostatic Model (NHM) operating at a 2-km grid resolution is nested inside the Regional Spectral Model (RSM) at 10-km grid resolution, which in turn is forced at the lateral boundaries by the Community Climate System Model (CCSM4). At this resolution, the climate change experiment allows for deep convection in model integrations, which is an important consideration for sub-tropical regions in general, and on islands with steep precipitation gradients in particular that strongly influence local ecological processes and the provision of ecosystem services. Projected precipitation change for this region of the Caribbean is simulated for the mid-twenty-first century (2041–2060) under the RCP8.5 climate-forcing scenario relative to the late twentieth century (1986–2005). The results show that by the mid-twenty-first century, there is an overall rainfall reduction over the island for all seasons compared to the recent climate but with diminished mid-summer drought (MSD) in the northwestern parts of the island. Importantly, extreme rainfall events on sub-daily and daily time scales also become slightly less frequent in the projected mid-twenty-first-century climate over most regions of the island.

Puerto Rico↗
USGS1968

Activity product constant of cryolite at 25°C and one atmosphere using selective-ion electrodes to estimate sodium and fluoride activities

The activity product constant of cryolite (Na 3 AlF 6 ) at 25&deg;C and 1 atm total pressure was calculated from data for solutions from which synthetic cryolite or mixtures of cryolite and a solid apparently related to ralstonite had precipitated. The activities of fluoride and of sodium were estimated using specific ion electrodes. The activity of Al 3+ was calculated from aluminum concentrations using equations which involve aluminum species existing in water solutions containing fluoride and hydroxide ions. For the reaction Na 3 AlF 6 ( c ) = 3 Na ( aq ) + + Al 3+ ( aq ) + 6 E - ( aq ) the activity product constant K so is 10 &minus;33.84 , and the standard free energy of formation at 25&deg;C is -745.4&plusmn;1.0 kcal mole &minus;1 . This latter is identical to a value from the literature which is based on calorimetric data. Although cryolite and related minerals are easily precipitated in the laboratory, their relative scarcity in nature suggests that the effect of influences, perhaps solutes other than those occurring in the structure, may inhibit or prevent the formation of cryolite.

Geochimica et Cosmochimica Acta↗
USGS1970

Fugacity of H2O from 0° to 350°C at the liquid-vapor equilibrium and at 1 atmosphere

The fugacity and fugacity coefficient of H 2 O at the liquid-vapor equilibrium, the fugacity and the Gibbs free energy of formation of H 2 O at 1 atm (1.01325 bars) total pressure have been calculated from published data on the physical and thermodynamic properties of H 2 O and are presented at ten-degree intervals from 0&deg; to 350&deg;C.

Geochimica et Cosmochimica Acta↗
USGS1976

The dissolution of calcite in CO 2 -saturated solutions at 25°C and 1 atmosphere total pressure

The dissolution of Iceland spar in CO 2 -saturated solutions at 25&deg;C and 1 atm total pressure has been followed by measurement of pH as a function of time. Surface concentrations of reactant and product species have been calculated from bulk fluid data using mass transport theory and a model that accounts for homogeneous reactions in the bulk fluid. The surface concentrations are found to be close to bulk solution values. This indicates that calcite dissolution under the experimental conditions is controlled by the kinetics of surface reaction. The rate of calcite dissolution follows an empirical second order relation with respect to calcium and hydrogen ion from near the initial condition (pH 3.91) to approximately pH 5.9. Beyond pH 5.9 the rate of surface reaction is greatly reduced and higher reaction orders are observed. Calculations show that the rate of calcite dissolution in natural environments may be influenced by both transport and surface-reaction processes. In the absence of inhibition, relatively short times should be sufficient to establish equilibrium.

Geochimica et Cosmochimica Acta↗
USGS1994

Relationships between atmospheric circulation and snowpack in the Gunnison River basin, Colorado

In this study, winter mean 700 mbar height anomalies over the eastern North Pacific Ocean and the western USA are related to variability in snowpack accumulations measured on or about 1 April at 21 snowcourse stations within and near the Gunnison River basin in Colorado. Results indicate that lower than normal snowpack accumulations are primarily associated with positive 700 mbar height anomalies (anomalous anticyclonic circulation) over the western USA. Moist air from the Pacific Ocean is moved to the north of the western USA along the western margin of the anomalous anticyclonic circulation. In contrast, higher than normal snowpack accumulations are associated with negative 700 mbar height anomalies (anomalous cyclonic circulation) over the western USA and over most of the eastern North Pacific Ocean. The anomalous cyclonic circulation over the western USA enhances the movement of moisture from the Pacific Ocean into the southern and central parts of the West. Results also indicate that variability in winter mean 700 mbar height anomalies can explain over 50% of the variability in snowpack accumulations in the Gunnison River basin. The significant linear relationships between 700 mbar height anomalies and snowpack accumulations in the Gunnison River basin can be used in conjunction with general circulation model simulations of 700 mbar height anomalies for future climatic conditions to estimate future snowpack accumulations in the Gunnison River basin.

Journal of Hydrology↗
USGS1974

Movement of elements into the atmosphere from coniferous trees in subalpine forests of Colorado and Idaho

Exudates from conifer trees, presumably consisting largely of volatile materials, were sampled at 19 subalpine localitites in Colorado and Idaho where anomalous amounts of several metals were determined in vegetation and mull during previous geochemical testing. The trees sampled were lodgepole pine ( Pinus contorta ), Engelmann spruce ( Picea engelmannii ) and Douglas fir ( Pseudotsuga menziesii ). The condensed exudates were passed through No. 40 Whatman filters, and through 5-micron, 0.45-micron, and 0.05-micron average-pore-diameter membrane filters, evaporated to dryness, and each residue was ashed and analyzed by a semiquantitative spectrographic method. The ashed residues of the exudates contain lithium, beryllium, boron, sodium, magnesium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, arsenic, strontium, yttrium, zirconium, molybdenum, silver, lead, bismuth, cadmium, tin, antimony, barium, and lanthanum. The presence of these elements suggests that volatile exudates from vegetation are a medium for the transport of elements in the biogeochemical cycle in subalpine environments. Thus, air sampling and analysis of aerosols derived from volatile exudates may be a useful tool in geochemical exploration.

Colorado, Idaho↗