Precipitation For Use Research Articles

MgO promoted by Fe2O3 and nitrate molten salt for fast and enhanced CO2 capture: Experimental and DFT investigation

Rapid and strong CO2 capture is critical in CO2 capture and utilization (CCU) techniques to mitigate global warming. Alkali molten salt (AMS) promoted-MgO sorbents with high capacity attracted attention, but their applications suffer from various limitations of low adsorption kinetics and poor stability. Here, AMS-promoted MgO sorbents corporation with Fe2O3 (Mg100-xFex-AMS10) were fabricated via modified methanol evaporation-induced surface precipitation for use in rapid and stable CO2 capture. Based on characterization of the sorbents, Mg98Fe2-AMS10 showed a loose flake structure, with a large surface area and numerous exposed active sites. Therefore, Mg98Fe2-AMS10 exhibited a strong CO2 capacity (14.86 mmolCO2/gsorbent at 300 °C) and good cyclic durability. Three kinetic models were explored, and the Avrami model provided a good prediction of the CO2 adsorption behavior, with Mg98Fe2-AMS10 exhibiting rapid adsorption kinetics. The adsorption mechanism was investigated using density functional theory (DFT) calculations. The charge transfer and bonding strengths of the surface O atoms on MgO increased, and these atoms preferentially bonded with activated CO2 (CO2∙−) under Fe catalysis. This study may provide insights into enhancing the CO2 capture and kinetics of MgO via combination with 3d transition metals.

A Long-term Global Comparison of IMERG and CFSR with Surface Precipitation Stations

As the Integrated MultisatellitE Retrievals for- Global Precipitation Measurement (GPM) (IMERG) products are expected to be available at least until mid-2030, it is highly desired that an extensive spatio-temporal comparison of IMERG be done at the in-situ level to have guidance on potential usage, especially for hydro-climatic applications in data-scarce conditions. For reference, we selected widely popular CFSR precipitation products and compared both (IMERG and CFSR) with monthly precipitation time-series accessed from in-situ global stations from National Oceanic and Atmospheric Adminstration (NOAA). This comparison was made over 2001–2020 for the extent of 5 geographical regions, 7 continents, 105 countries and ~ 50,000 surface stations using the standard metrices like NSE, VE, KGE, R, RMSE and PBIAS. IMERG has a satisfactory to a good simulation of monthly rainfall in the majority of the regions, continents, countries, and stations and outperforms Climate Forecast and System Reanalysis (CFSR). Precisely, satisfactory simulation of monthly precipitation was found for Europe (VE = 0.61), North America (0.56) and Australia (0.56) and unsatisfactory simulation was observed for other continents for CFSR. At country levels, 64 countries reveal a significantly better mean NSE with IMERG. Considering the value of automated global access to the latest precipitation data for hydrologic modelling, and the better quality of IMERG, this study also introduces a public web service: Worldwide Weather Service (W3S) for preprocessing and dissemination of IMERG precipitation for use in hydrologic modelling. The outcomes of the study are expected to guide water resources managers to use these datasets in sustainable water resources management.

Evaluation of Eight High-Resolution Gridded Precipitation Products in the Heihe River Basin, Northwest China

The acquisition of the precise spatial distribution of precipitation is of great importance and necessity in many fields, such as hydrology, meteorology and ecological environments. However, in the arid and semiarid regions of Northwest China, especially over mountainous areas such as the Heihe River basin (HRB), the scarcity and uneven distribution of rainfall stations have created certain challenges in gathering information that accurately describes the spatial distribution of precipitation for use in applications. In this study, the accuracy of precipitation estimates from eight high-resolution gridded precipitation products (CMORPHv1-CRT, CRU TSv.4.05, ERA5, GSMaP_NRT, IMERG V06B-Final, MSWEPv2.0, PERSIANN-CDR and TRMM 3B42v7) are comprehensively evaluated by referring to the precipitation observations from 23 stations over the HRB using six indices (root mean square error, standard deviation, Pearson correlation coefficient, relative deviation, mean error and Kling–Gupta efficiency) from different spatial and temporal scales. The results show that at an annual scale, MSWEP has the highest accuracy over the entire basin, while PERSIANN, CRU and ERA5 show the most accurate results in the upper, middle and lower reaches of the HRB, respectively. At a seasonal scale, the performance of IMERG, CRU and ERA5 is superior to that of the other products in all seasons in the upper, middle and lower reaches, respectively. Over the entire HRB, PERSIANN displays the smallest deviation in all seasons except for spring. TRMM shows the highest accuracy in spring and autumn, while MSWEP and CRU show the highest accuracy in summer and winter, respectively. At a monthly scale, TRMM is superior to the other products, with a relatively stronger correlation almost every month, while GSMaP is inferior to the other products. Moreover, MSWEP and PERSIANN perform relatively best, with favorable statistical results around almost every station, while GSMaP shows the worse performance. In addition, ERA5 tends to overestimate higher values, while GSMaP tends to overestimate lower values over the entire basin. Moreover, the overestimation of ERA5 tends to appear in the upper reach area, while that of GSMaP tends to appear in the lower reach area. Only CRU and PERSIANN yield underestimations of precipitation, with the strongest tendency appearing in the upper reach area. The results of this study display some findings on the uncertainties of several frequently used precipitation datasets in the high mountains and poorly gauged regions in the HRB and will be helpful to researchers in various fields who need high-resolution gridded precipitation datasets over the HRB, as well as to data producers who want to improve their products.

The Role of Ab-Anbars in the Vernacular Architecture of Iran with Emphasis on the Performance of Wind-Catchers in Hot and Dry Climates

Vernacular and traditional Iranian architecture has always acted rationally, harmoniously, and climate-friendly to meet the needs of the people in dealing with the environment. In addition, without harming the environment, they have achieved the best initiatives with the least facilities. For example, we can mention that the Ab-Anbars in arid and desert areas of Iran, which are used to store water in seasons with precipitation for use in the rest of the year, has been an optimal way to use natural resources and provide climate comfort. The Ab-Anbars are realized with ventilated cisterns through openings on their roof or wind-catchers to keep the water cool and provide comfortable conditions for the occupants. In order to study the essential role of natural ventilation and cooling in the Ab-Anbars, thermal analysis with CFD software was carried out to assess the effectiveness of a typical wind-catcher according to different wind directions in Yazd city. The results showed that Ab-Anbars have played an important role in reducing cooling loads and supply the necessary ventilation rate of buildings and can be used in the future for application in contemporary architecture and urban planning.

Exploring Topography‐Based Methods for Downscaling Subgrid Precipitation for Use in Earth System Models

AbstractTopography exerts major control on land surface processes. To improve representation of topographic impacts on land surface processes, a new topography‐based subgrid structure has been introduced to the Energy Exascale Earth System Model to represent the subgrid heterogeneity of surface elevation. To take advantage of the new subgrid structure for improving land surface modeling, this study explores four topography‐based methods for downscaling grid precipitation to the subgrids. In the first three methods, the deviation of the subgrid precipitation from the grid mean is equal to the grid precipitation multiplied by the ratio of the elevation difference between the subgrid and grid mean to a specified elevation, which is equal to grid elevation, difference between the maximum and minimum subgrid elevation, and maximum subgrid elevation, respectively. The second method limits the ratio to 0.5 to avoid extreme values in mountains, and the third method utilizes the subgrid hypsometric elevation. The fourth method is similar to the third method except that a height rise determined based on an ambient flow regime with the Froude number equals to 1 is used to limit the numerator. The downscaled precipitation is evaluated using the Precipitation‐elevation Regressions on Independent Slopes Model precipitation data over the United States and statistical metrics. Results show that by utilizing the subgrid hypsometric elevation, the third and fourth methods show clear advantages over the first and second methods. Furthermore, introducing the height rise in the fourth method improves downscaling skill slightly compared to the third method consistently across multiple grid sizes in areas with larger subgrid heterogeneity.

Thermal and structural properties of magnesium tetraborate produced by solid state synthesis and precipitation for use in thermoluminescent dosimetry

Magnesium tetraborate is a phosphor with relevant characteristics for radiation dosimetry purposes. One of the main challenges on this material is still the understanding of its structure and luminescent processes involved in dosimetric performance. In this work, all the steps of the material production through DTA/TG, XRD and SEM techniques were evaluated to understand the main physical and chemical changes during the thermal process (calcination and sinterization) to produce the MgB4O7 samples. Two synthesis processes of MgB4O7 were studied: precipitation (P.S) and solid state (S.S). Finally, the luminescence efficiency of the pellets was investigated in function of different sintering temperatures. The initial stage of DTA/TG curves of the material just after the mixing of starting materials, regardless the synthesis, is marked by endothermic events caused by dehydration, decomposition of hydroxyl groups and hydrated borate phases. At higher temperatures, the curves are marked by exothermic events related to crystalline transitions, but the peak obtained for the S.S is better defined in comparison to P.S. Moreover, the DTA/TG analyses of the pellets prior and after the sinterization, showed that the process is more relevant for the MgB4O7 pellets produced by S.S (950 °C), dramatically reducing its higroscopicity. The SEM images reinforce the importance of the sintering process to create a resistant detector and with a more homogenous and cohesive surface, therefore increasing it luminescence properties. The thermoluminescent (TL) sensitivity of MgB4O7:Dy0,5% pellets produced via S.S, sintered at 950 °C, is 4 times higher compared to the ones sintered at 950 °C, via P.S. The materials produced via P.S did not present relevant changes in their TL sensitivity for sintering temperatures above 400 °C.

A Deterministic Approach for Approximating the Diurnal Cycle of Precipitation for Use in Large-Scale Hydrological Modeling

Abstract Accurate characterization of precipitation P at subdaily temporal resolution is important for a wide range of hydrological applications, yet large-scale gridded observational datasets primarily contain daily total P. Unfortunately, a widely used deterministic approach that disaggregates P uniformly over the day grossly mischaracterizes the diurnal cycle of P, leading to potential biases in simulated runoff Q. Here we present Precipitation Isosceles Triangle (PITRI), a two-parameter deterministic approach in which the hourly hyetograph is modeled with an isosceles triangle with prescribed duration and time of peak intensity. Monthly duration and peak time were derived from meteorological observations at U.S. Climate Reference Network (USCRN) stations and extended across the United States, Mexico, and southern Canada at 6-km resolution via linear regression against historical climate statistics. Across the USCRN network (years 2000–13), simulations using the Variable Infiltration Capacity (VIC) model, driven by P disaggregated via PITRI, yielded nearly unbiased estimates of annual Q relative to simulations driven by observed P. In contrast, simulations using the uniform method had a Q bias of −11%, through overestimating canopy evaporation and underestimating throughfall. One limitation of the PITRI approach is a potential bias in snow accumulation when a high proportion of P falls on days with a mix of temperatures above and below freezing, for which the partitioning of P into rain and snow is sensitive to event timing within the diurnal cycle. Nevertheless, the good overall performance of PITRI suggests that a deterministic approach may be sufficiently accurate for large-scale hydrologic applications.

Integrated climate change risk assessment: A practical application for urban flooding during extreme precipitation

Risk assessments of flooding in urban areas during extreme precipitation for use in, for example, decision-making regarding climate adaptation, are surrounded by great uncertainties stemming from climate model projections, methods of downscaling and the assumptions of socioeconomic impact models. The multidisciplinary character of such risk assessments also requires that research groups and experts from different scientific disciplines combine knowledge and share model outputs. This paper describes an integrated framework and tool, the Danish Integrated Assessment System (DIAS), which has been designed to address the complex linkages between the different kinds of data required in assessing climate adaptation. It emphasizes that the availability of spatially explicit data can reduce the overall uncertainty of the risk assessment and assist in identifying key vulnerable assets. The usefulness of such a framework is demonstrated by means of a risk assessment of flooding from extreme precipitation for the city of Odense, Denmark. A sensitivity analysis shows how the presence of particularly important assets, such as cultural and historical heritage, may be addressed in assessing such risks. The output of the risk assessment for Odense indicates that highly detailed geographical data reduce the overall uncertainty and assist climate adaptation decision-makers in focusing on protecting those assets that are considered to be relevant in the given context. Also, using an integrated framework such as DIAS enables the relative importance of the different factors (i.e. degree of climate change, assets value, discount rate etc.) to be determined, thus influencing the overall output of the assessment.

Influence of aging time on the microstructural characteristics of a Cu/ZnO-based catalyst prepared by homogeneous precipitation for use in methanol steam reforming

Nanocrystalline Cu–ZnO-based catalysts were successfully synthesized via a homogeneous precipitation method. Four aging times were used to prepare the catalysts (1, 3, 12 and 24 h) to study the influence on their textural, structural and catalytic properties. The samples were characterized by N2 adsorption, powder X-ray diffraction, thermogravimetric analysis, H2 temperature-programmed desorption and transmission electron microscopy, and the samples were applied to the steam reforming of methanol. The crystallinity and purity of the aurichalcite phase precursor was enhanced after 3 h of aging. Structural changes were observed in the calcined catalysts as the aging time increased. A decreased CuO crystallite size was produced at longer aging times, which enhanced the CuO dispersion and Cu–ZnO interactions. These factors affected the catalytic activity. The catalyst aged for 24 h showed the highest methanol conversion, and a correlation between the structure and activity was verified.

Production of starch nanoparticles by dissolution and non-solvent precipitation for use in food-grade Pickering emulsions

The aim of this study was to investigate non-solvent precipitation of starch to produce nanoparticles that could be used in Pickering emulsions. The material used was waxy maize, modified with octenyl succinic anhydride. Different methods of non-solvent precipitation were investigated, and a method based on direct mixing of an 8% starch solution and ethanol (ratio 1:1) was found to produce the smallest particles. The particle size was measured using AFM and AF4, and was found to be in the range 100–200nm. However, both larger particles and aggregates of nanoparticles were observed. The emulsion produced using the precipitated starch particles had a droplet size that between 0.5 and 45μm, compared to emulsions produced from waxy maize granules, in which had a size of 10–100μm. The drop in size contributed to increased stability against creaming. The amount of starch used for emulsion stabilization could also be substantially reduced.

Microwave Augmented Fabrication and Evaluation of CNT-Reinforced Nanohydroxyapatite

Bioactive CNT reinforced hydroxyapatite nano-composite is synthesized by in-situ precipitation for use in load bearing orthopedic applications. Microwaves augment the synthesis, enhance the reaction rate, and institute energy savings. Heat and acid treated purified CNTs in microwaves are functionalized and dispersed in calcium nitrate tetrahydrate. Diammonium hydrogen phosphate is incorporated in calcium ion solution to furnish the required Ca:P ratio. Refluxing of the precursor solution is accomplished under microwaves. XRD shows the phase purity and crystallinity, FTIR spectroscopy indicates the fucntionalization of CNTs and SEM analysis depicts the nanoporous nanomorphology of synthesized powder. TGA measures the thermal endurance of product, showing good CNTs retention at high temperatures (1100°C) in nitrogen ambient, otherwise they get oxidized in air in that temperature range. CNT reinforced sintered biomaterial exhibits excellent consolidation and a Vicker hardness increment of 30%. The relation of between mechanical properties and sintering time is correlated by SEM.

Adolescent first lapse following smoking cessation: Situation characteristics, precipitants and proximal influences

Despite increased attention to adolescent smoking cessation, little is known about adolescent relapse following a quit attempt. To address this issue, the present study was designed to provide initial information regarding the characteristics of adolescent lapses to smoking following abstinence. Included in the present study were 204 adolescent participants in four independent smoking cessation trials. For the full sample, participants averaged 15.99 (1.27) years of age; 56% were female and 78% were white. Lapse characteristics and precipitants were assessed using the Adolescent Smoking Relapse Review. Three domains of the lapse experience were assessed: lapse situation characteristics, precipitants of use in the situation, and proximal influences (i.e., potential precipitants occurring on the same day, prior to the lapse situation). Participant reports indicated that the modal lapse situation occurred in the evening while socializing with friends at home. Urges or cravings and social pressure were commonly endorsed as occurring in lapse situations. The most frequently reported proximal influence was desire for a cigarette, followed by abstinence-violation cognitions (okay to smoke occasionally, wanted to see what it would be like) and negative emotions. The findings indicate that a broad range of factors appear to influence adolescent smoking lapse and commend the value of incorporating content relevant to managing social and affective cues, strategies for inhibiting the prepotent response to ask for a cigarette, addressing cognitions regarding the difficulty of not smoking (i.e., cessation expectancies) and combating perceptions of the ability to smoke occasionally.

Herbage Response to Precipitation in Central Alberta Boreal Grasslands

The dependence between grassland herbage production and precipitation within the Boreal region of central Alberta was evaluated. Additional objectives were to compare current year growing season (e.g., April or May, to August) precipitation with 12 and 16 month water year (e.g., dormant and growing season) precipitation for use in predicting herbage growth, and determine whether lowland and upland grasslands differ in their response to precipitation. Lowland herbage production averaged 6,053 kg ha -1 , nearly twice the 3,153 kg ha -1 found on upland grasslands during the study. In general, herbage production correlated significantly with precipitation, but the magnitude and direction of that relationship varied depending on grassland type. Uplands displayed a positive linear relationship with precipitation (r = 0.76; p < 0.01), while lowland communities displayed a negative curvilinear (R 2 = 0.65; p < 0.05) relationship. Furthermore, while herbage production on uplands was better predicted by current year precipitation, lowland production appeared more heavily dependent on precipitation falling during the water year, the latter of which included fall and winter moisture recharge. We hypothesize that these differences are linked to water redistribution within the landscape, along with subsequent soil temperature regimes and the length of effective growing season. Given the influence of topography in regulating water availability and use, rangeland managers within the Boreal region should use caution when determining rangeland carrying capacity from meteorological data.

Herbage response to precipitation in central Alberta boreal grasslands

The dependence between grassland herbage production and precipitation within the Boreal region of central Alberta was evaluated. Additional objectives were to compare current year growing season (e.g., April or May, to August) precipitation with 12 and 16 month water year (e.g., dormant and growing season) precipitation for use in predicting herbage growth, and determine whether lowland and upland grasslands differ in their response to precipitation. Lowland herbage production averaged 6,053 kg ha(-1), nearly twice the 3,153 kg ha(-1) found on upland grasslands during the study. In general, herbage production correlated significantly with precipitation, but the magnitude and direction of that relationship varied depending on grassland type. Uplands displayed a positive linear relationship with precipitation (r = 0.76; p &lt; 0.01), while lowland communities displayed a negative curvilinear (R2 = 0.65; p &lt; 0.05) relationship. Furthermore, while herbage production on uplands was better predicted by current year precipitation, lowland production appeared more heavily dependent on precipitation falling during the water year, the latter of which included fall and winter moisture recharge. We hypothesize that these differences are linked to water redistribution within the landscape, along with subsequent soil temperature regimes and the length of effective growing season. Given the influence of topography in regulating water availability and use, rangeland managers within the Boreal region should use caution when determining rangeland carrying capacity from meteorological data.

The Global Precipitation Climatology Project: First Algorithm Intercomparison Project

The Global Precipitation Climatology Project (GPCP) was established by the World Climate Research Program to produce global analyses of the area- and time-averaged precipitation for use in climate research. To achieve the required spatial coverage, the GPCP uses simple rainfall estimates derived from IR and microwave satellite observations. In this paper, we describe the GPCP and its first Algorithm Intercomparison Project (AIP/1), which compared a variety of rainfall estimates derived from Geostationary Meteorological Satellite visible and IR observations and Special Sensor Microwave/Imager (SSM/I) microwave observations with rainfall derived from a combination of radar and raingage data over the Japanese islands and the adjacent ocean regions during the June and mid-July through mid-August periods of 1989. To investigate potential improvements in the use of satellite IR data for the estimation of large-scale rainfall for the GPCP, the relationship between rainfall and the fractional coverage of cold clouds in the AIP/1 dataset is examined. Linear regressions between fractional coverage and rainfall are analyzed for a number of latitude-longitude areas and for a range of averaging times. The results show distinct differences in the character of the relationship for different portions of the area. These results suggest that the simple IR-based estimation technique currently used in the GPCP can be used to estimate rainfall for global tropical and subtropical areas, provided that a method for adjusting the proportional coefficient for varying areas and seasons can be determined.

A Statistical Analysis of Precipitation Frequency in the Conterminous United States, Including Comparisons with Precipitation Totals

An alternative measure of time-aggregated precipitation for use in short-term climate studies is developed. This measure, precipitation frequency, is defined as the number of days per month or season with total amounts ≥ 2.54 mm (0.10 inch). Newly created data sets for the period 1951–80 are used as a basis for describing large-scale spatial and temporal features of precipitation frequency for the mainland United States. Comparisons between precipitation frequency and the conventional statistic, total precipitation, indicate that frequency is more normally distributed and more spatially coherent than total precipitation. Factor analysis and an orthogonal rotation to the varimax criterion are used to identify synoptic-scale, spatially coherent regions of precipitation frequency. The regions are generally consistent with previously documented cyclone trajectories.

A Method for Modeling the Deposition of Sulfur by Precipitation over Regional Scales

Radioactive fallout data suggest that the concentration of pollutants in rainfall, while highly variable, might be described on the average by about an inverse half-power dependence on the amount of precipitation. Recent measurements of sulfur concentrations in summer rainfall collected at Argonne National Laboratory tend to support this contention, as do preliminary results derived from operations of the DOE precipitation chemistry network. The concept is extended to develop a bulk removal rate for airborne total sulfur by precipitation for use in regional dispersion modeling.