Ultraviolet-B radiation (UV-B, 280-320 nm) has important effects in urban areas, including those ... more Ultraviolet-B radiation (UV-B, 280-320 nm) has important effects in urban areas, including those on human health. Broadband UV-B radiation is monitored i n Baltimore, MD, as part of the Baltimore Ecosystem Study, a long-term ecological research program. We compare broadband UV-B irradiance in Baltimore with UV-B a t two nearby locations: a more rural station 64 km southeast and a suburban station 42 km southwest. The monitoring station in Baltimore is on the roof of a 33-m-tall building; there are no significant obstructions to sky view. T h e U S. Department of Agriculture UV-B Monitoring and Research Program provided all sensors, which were calibrated at the National Oceanic and Atmospheric Administration Central UV Calibration Facility. UV-B irradiances at the three sites eenerallv were similar. Over all-~ ~~~conditions, Baltimore and the suburban site measured 3.4% less irradiance than the rural site. This difference is within the anticipated +3% calibration uncertainty of the pyranometers. On 59 days with clond-free conditions at all three sites, average differences in measured UV-B among the three sites were even smaller; Baltimore measured 1.2% less irradiance than the rural site. High aerosol optical thkkness stmngly reduced daily UV-B dose, whereas [SO2] had no influence. Surface 0, increased with increasing UV-B dose when [NO,] exceeded 10 pph. (Posted on the website on 30 August ZOW.
The influences of acidic precipitation on the environment has been in the forefront of discussion... more The influences of acidic precipitation on the environment has been in the forefront of discussion across the United States for at least the past ten years. Precipitation at four sites within the state of Indiana has been collected for chemical analysis since 1984 as part of the National Atmospheric Deposition Program (NADP). Analysis of the concentrations and depositions of the various precipitation constituents helps describe the atmospheric environment and the impact the environment has on the ground surface chemistry. Of particular interest is the amount, variability and sources of acidity within the precipitation, as well as the climatology of the storm systems depositing the precipitation. A description of the results for the NADP site at the Purdue Agronomy Farm near West Lafayette, Indiana (3) indicated that the sulfate deposition was largely accounted for by oxidation reactions on sulfur dioxide and that both sulfate and nitrate were highly correlated with the precipitation pH. The West Lafayette site is remote from large sources of sulfur dioxide, nitrous oxides or flyash, with only one power plant (to the south of the site) within 50km (13). This study described the wet deposition from October 1984 to December 1986 at the Southwest Purdue Agricultural Center near Vincennes, Indiana which is situated in the vicinity of six power plants (surrounding the site) within 50 km (13). Both sites are classified by (13) as rural. Methods The Climatological Data for Vincennes, Indiana (18) were used to determine the normality of the precipitation during the period of study. The wet deposition samples were collected according to NADP protocol (13) on Tuesday of each week. The water soluble hydrogen (H +), sulfate (S0 4 2~) , nitrate (N0 3~) , ammonium (NH 4 +), chloride (Cl~), magnesium (Mg 2 +), orthophosphate (P0 4 2~) , and calcium (Ca 2 +) concentrations of the wet deposition samples were analyzed by the Central Analytical Laboratory of the NADP in accordance with NADP procedures (11, 12). Precipitation amount were recorded using a Belfort weighing rain gauge. Many sampling periods within the study period were not used due to high levels of contamination, negligible or no precipitation samples, or poor operation of the collector. If the sample had: a) no precipitation, b) precipitation less than 0.127 cm, c) P04 2~c oncentrations greater than 0.05 mg/L, or d) a sampler efficiency (defined as the percent of rain gauge-recorded precipitation collected in wet bucket sample) less than 75% it was not included in the data analysis. Of the initial 116 weeks included in the study period, 69 weeks passed the above criteria. These weeks were separated by season where December, January, and February defined the winter season and each season following was defined by three consecutive months (17). The 69 weeks of good wet deposition samples were distributed as 17, 15, 23, 14 in the spring, summer, fall, and winter respectively. Note that this is not a climatological series, but rather a set of precipitation periods over a 27-month period. Since the results
Forecast models of solar radiation incorporating cloud effects are useful tools to evaluate the i... more Forecast models of solar radiation incorporating cloud effects are useful tools to evaluate the impact of stochastic behaviour of cloud movement, real-time integration of photovoltaic energy in power grids, skin cancer and eye disease risk minimisation through solar ultraviolet (UV) index prediction and bio-photosynthetic processes through the modelling of solar photosynthetic photon flux density (PPFD). This research has developed deep learning hybrid model (i.e., CNN-LSTM) to factor in role of cloud effects integrating the merits of convolutional neural networks with long short-term memory networks to forecast near real-time (i.e., 5-minute) PPFD in a sub-tropical region Queensland, Australia. The prescribed CLSTM model is trained with real-time sky images that depict stochastic cloud movements captured through a Total Sky Imager (TSI-440) utilising advanced sky image segmentation to reveal cloud chromatic features into their statistical values, and to purposely factor in the clou...
Anaerobic decomposition in manure storage contributes to hydrogen sulfide (H2S) and methane (CH4)... more Anaerobic decomposition in manure storage contributes to hydrogen sulfide (H2S) and methane (CH4) emissions. Coincident emission measurements were made of these gases from a western free stall dairy manure storage basin over a two-month period (August and September) as manure filled the basin and dried to assess the similarity or differences in the emissions characteristics. Path-integrated CH4 concentrations were measured from sampled air using photoacoustic spectrometric technology. Half-hourly emissions were determined using a backward Lagrangian Stochastic method utilizing on-site turbulence measurements. The median daily CH4 emission for the basin was 3.5 mg CH4 m−2 s−1 (772 g d−1 hd−1). Aging of the manure over the 44 days of this study did not appear to influence the CH4 emissions. A high correlation between the CH4 and H2S emissions during the study period suggested that the production and transport of these two gases from the basin were influenced by the same factors. Emiss...
Open-path Fourier transform infrared spectroscopy (OP-FTIR) is susceptible to environmental varia... more Open-path Fourier transform infrared spectroscopy (OP-FTIR) is susceptible to environmental variables which can become sources of errors for gas quantification. In this study, we assessed the effects of water vapour, temperature, path length, and wind speed on the uncertainty of nitrous oxide (N 2 O) and carbon dioxide (CO 2) concentrations derived from OP-FTIR spectra. The presence of water vapour resulted in underestimating N 2 O in both lab (−3 %) and field (−12 %) experiments at 30 °C using a classical least squares (CLS) model. Differences in temperature between the sample and reference spectra also underestimated N 2 O concentrations due to temperature broadening and the increased interferences of water vapour in spectra of wet samples. Changes in path length resulted in a non-linear response of spectra and bias (e.g. N 2 O and CO 2 concentrations were underestimated by 30 % and 7.5 %, respectively, at the optical path of 100 m using CLS models). For N 2 O quantification, partial least squares (PLS) models were less sensitive than CLS to the influence of water vapour, temperature, and path length, and provided more accurate estimations. Uncertainties in the path-averaged concentrations increased in low wind conditions (< 2 m s-1). This study identified the most common interferences that affect OP-FTIR measurements of N 2 O and CO 2. The quantified errors can be used as references for current or future OP-FTIR users. 1 Introduction Agriculture substantially contributes greenhouse gases (GHGs), mostly N 2 O and CH 4 , to the atmosphere (IPCC, 2007). In 2010, emissions led by agricultural activities (e.g. crop production and livestock management) were estimated between 5.2 and 5.8 Gt of CO 2 equivalent per year, accounting for 10-12 % global anthropogenic emissions (IPCC, 2014). Estimations of gas fluxes over an extended period (e.g. growing seasons) is complicated due to the dynamic and episodic nature of gas emissions and measurement complexities. The integrated uses of fast-response gas concentration sensors and micrometeorological techniques were developed to measure long-term gas fluxes continuously (Baldocchi, 2003; Denmead, 2008; Flesch et al., 2016). Open-path Fourier transform spectroscopy (OP-FTIR) is capable of measuring concentrations of multiple gases simultaneously with high temporal and spatial resolution through real-time measurements and path-averaged concentrations (Russwurm and Childers, 2002). OP-FTIR has been applied to measure GHGs, and other trace gases (e.g.
The carbon exchange between ecosystems and the atmosphere has a large influence on the Earth syst... more The carbon exchange between ecosystems and the atmosphere has a large influence on the Earth system and specifically on the climate. This exchange is therefore being studied intensively, often using the eddy covariance (EC) technique. EC measurements provide reliable results under turbulent atmospheric conditions, but under stable conditions-as they often occur at night-these measurements are known to misrepresent exchange fluxes. Nocturnal boundary layer (NBL) budgets can provide independent flux estimates under stable conditions, but their application so far has been limited by rather high cost and practical difficulties. Unmanned aircraft systems (UASs) equipped with trace gas analysers have the potential to make this method more accessible. We present the methodology and results of a proof of concept study carried out during the ScaleX 2016 campaign. Successive vertical profiles of carbon dioxide dry air mole fraction in the NBL were taken with a compact analyser carried by a UAS. We estimate an average carbon dioxide flux of 12 µmol • m −2 • s −1 , which is plausible for nocturnal respiration in this region in summer. Transport modelling suggests that the NBL budgets represent an area on the order of 100 km².
Open-path Fourier transform infrared spectroscopy (OP-FTIR) has often been used to measure hazard... more Open-path Fourier transform infrared spectroscopy (OP-FTIR) has often been used to measure hazardous or trace gases from the "hot" point sources (e.g., volcano, industrial or agricultural facilities) but seldom used in the field-scale source areas, such as soil emissions. OP-FTIR, the close-path mid-IR laser-based N 2 O, and the nondispersive-IR CO 2 analyzers were used to measure the concentrations of greenhouse gases (e.g., N 2 O and CO 2) emitted from agricultural soils over a period of 9-19 th June in 2014. We developed a quantitative method of N 2 O/CO 2 analysis that minimized the interferences from diurnal changes of humidity and temperature in order to measure N 2 O/CO 2 concentrations accurately. Two chemometric multivariate models were developed, a classical least squares (CLS) and a partial least squares (PLS), respectively. This study evaluated different methods to generate the single beam background spectra, and different spectral regions to determine N 2 O/CO 2 concentrations from OP-FTIR spectra. A standard extractive method was used to measure the 'actual' path-averaged concentrations along an OP-FTIR optical path in situ, as a benchmark to assess the feasibilities of these quantitative methods. Within the absolute humidity of 5,000-20,000 ppmv and the temperature of 10-35 °C, we found that the CLS model underestimated N 2 O concentrations (Bias =-4.9±3.1 %) calculated from OP-FTIR spectra, and the PLS model improved the accuracy of the calculated N 2 O (Bias = 1.4±2.3 %). The bias of the calculated CO 2 was-1.0±2.8 % using the CLS model. These methods suggested that the changed ambient factors potentially led to biases in N 2 O/CO 2 estimations from OP-FTIR spectra, and may help the OP-FTIR user to escape from the dependency of extractive methods used to calibrate the concentration determined by OP-FTIR. 1 Introduction Agriculture contributes a substantial amount of greenhouse gas (GHG) emissions (e.g. N 2 O, CO 2 , and CH 4) to the global
Manure management by dairies is estimated to account for 6% of the greenhouse gas warming potenti... more Manure management by dairies is estimated to account for 6% of the greenhouse gas warming potential of all agricultural emissions in the USA. Emissions methane (CH 4) and carbon dioxide (CO 2) were measured from manure storage facilities at two Midwestern dairies (an Indiana lagoon and two Wisconsin basins). The CH 4 concentrations were measured using photoacoustic infrared absorption spectroscopy and flame ionization gas chromatography. The CO 2 concentrations were measured using photoacoustic infrared absorption spectroscopy and non-dispersive infrared spectroscopy. Emissions were estimated using a backward Lagrangian Stochastic model with on-site turbulence measurements. The WI basins emitted more CH 4 and CO 2 than the waste lagoon in IN on an animal basis. Peak emissions were episodic. Mean daily CH 4 emissions during the fall (October) from the WI basins and IN lagoon were 295 g hd −1 d −1 (374 g AU −1 d −1) and 47 g hd −1 d −1 (59 g AU −1 d −1), respectively. Mean CO 2 emissions during the fall were 575 g hd −1 d −1 (374 g AU −1 d −1) from the WI basins (October) and 107 g hd −1 d −1 (135 g AU −1 d −1) from the IN lagoon (September). Emissions were not resolvable (approximately emissions MDL) when the storage area surface was frozen. Methane emissions contributed eight-ten times the radiative warming potential of CO 2 (animal basis) at both dairies. Mean daily CO 2-equivalent emissions from the WI basins (IN lagoon) ranged from highs of 7.9 kg CO 2-e hd −1 d −1 in October (2.6 kg CO 2-e hd −1 d −1 in September) to lows of 1.6 kg CO 2-e hd −1 d −1 (0.4 kg CO 2-e hd −1 d −1) in December through January. Air temperature was correlated with CH 4 and CO 2 emissions at the WI basin but not the IN lagoon. Wind speed was weakly correlated with CH 4 emissions (but not CO 2 emissions) at both dairies. While weather conditions were similar, the separation of solids prior to storage contributed to lower CH 4 and CO 2 emissions and lower greenhouse warming potential per animal. Cooler climatic conditions decreased CH 4 and CO 2 emissions as well as decreasing the mass ratio of CH 4-CO 2 emissions.
Figure 2-Daily variation in UVB irradiance. The mean and standard deviations of the UVB irradianc... more Figure 2-Daily variation in UVB irradiance. The mean and standard deviations of the UVB irradiance at Queenstown (open circles, heavy bar) and Baltimore (closed circles, light bar) are indicated. Figure 1-Locations of UVB (filled circles) and some of the surface air quality (open circles) measurements made in the Washington-Baltimore area.
Agricultural activities account for approximately 25% of worldwide greenhouse gas emissions. Farm... more Agricultural activities account for approximately 25% of worldwide greenhouse gas emissions. Farm management practices, such as tillage and no-tillage, may contribute more to this percentage than others. The two most abundant greenhouse gases responsible for climate change are CO2 and H2O, therefore it is important to determine whether tillage or no-tillage emits less of these gases. Fluxes of CO2 and H2O from two maize canopy fields, one with tillage and one with no-tillage, were measured in Indiana during the 2016 growing season. This study utilized the eddy covariance method, which represents flux as a covariance between vertical velocity and gas concentration. Measurements of canopy height and leaf area index (LAI) from both fields were collected since these parameters influence photosynthesis, respiration, and evapotranspiration rates and show differences in the growth of maize. Results showed that the tilled field had a 14% higher maximum CO2 uptake and a 4% higher maximum H2O...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Stochastic Environmental Research and Risk Assessment, 2022
Forecast models of solar radiation incorporating cloud effects are useful tools to evaluate the i... more Forecast models of solar radiation incorporating cloud effects are useful tools to evaluate the impact of stochastic behaviour of cloud movement, real-time integration of photovoltaic energy in power grids, skin cancer and eye disease risk minimisation through solar ultraviolet (UV) index prediction and bio-photosynthetic processes through the modelling of solar photosynthetic photon flux density (PPFD). This research has developed deep learning hybrid model (i.e., CNN-LSTM) to factor in role of cloud effects integrating the merits of convolutional neural networks with long short-term memory networks to forecast near real-time (i.e., 5-min) PPFD in a sub-tropical region Queensland, Australia. The prescribed CLSTM model is trained with real-time sky images that depict stochastic cloud movements captured through a total sky imager (TSI-440) utilising advanced sky image segmentation to reveal cloud chromatic features into their statistical values, and to purposely factor in the cloud v...
Figure 1 – Correlation in the components to H300 between a site in Bondville, Illinois (i) and La... more Figure 1 – Correlation in the components to H300 between a site in Bondville, Illinois (i) and Lafayette, Indiana (j) separated by 131 km.
Ammonia emission inventories from livestock waste lagoons across the USA are generally based on c... more Ammonia emission inventories from livestock waste lagoons across the USA are generally based on chamber studies that do not include the influence of actual meteorological conditions on the exchange between lagoon or basin surfaces and the atmosphere. Ammonia (NH3) emissions from waste lagoons or basins were measured periodically for two years at swine and dairy operations across the United States as part of the National Air Emissions Monitoring Study. Path-integrated NH3 concentrations were measured using tunable diode lasers with emissions determined from on-site turbulence measurements in conjunction with inverse dispersion and integrated horizontal flux models. Emissions from livestock operations in the western USA were influenced by wind speed, animal live mass, air temperature, and probably the vapor pressure deficit. Average daily emissions from sow and finishing farm waste lagoons in OK were similar with annual average daily mean emissions of 130 g d -1 AU -1 (1 animal unit, ...
Currently the northern temperate regions have lost stratospheric ozone at 4% to 7% per decade (Ma... more Currently the northern temperate regions have lost stratospheric ozone at 4% to 7% per decade (Madronich et al., 1998). For latitudes associated with the northern deciduous forest in Indiana this corresponds to 10 to 20 DU (Dobson units). This decreased stratospheric ozone corresponds to increased solar ultraviolet (UV) radiation at the top of forest canopies. Furthermore under climate warming scenarios, we would expect more frequent penetration of tropical air masses with associated low stratospheric ozone levels into mid-latitudes thereby increasing the variability in surface solar UV radiation. Changes in the onset of warmer conditions will likely shifts the time of leaf-out of temperate forests (Kramer et al., 2000). The impact of these climate changes on UVB exposure of plant species in the herbaceous layer of the temperate deciduous forest is unknown since changes in UV exposure associated with changes in phenology may shift competitive advantage to different species (Gold and...
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