Dry Precipitation Research Articles

Evaluating the effects of different nutrient management strategies on apple (malus pumila) in intensive orchards of Kazakhstan. Results from a 4-year study

This article presents the findings of a four-year study in intensive apple orchards in southern Kazakhstan, evaluating different nutrient management strategies on apple trees (Malus pumila). The research aimed to assess the impact of nutrition plans on tree growth, productivity, and fruit quality, considering the region's unique soil and climate. The experiment, established in 2014, covered 1.5 hectares and consisted of Jeromini apple trees grafted onto M9 rootstock. Three treatment groups were established: a control group with no additional nutrition, a group with nutrition based on a generally accepted program, and a group with nutrition tailored to the apple tree's needs with fertigation. Phenological and biometric observations were conducted regularly from 2019 to 2022 to monitor tree performance. Soil and leaf samples were analyzed for nutrient content, and soil properties like pH and salinity were assessed. Statistical analysis was used to identify significant differences among the treatment groups. The research was conducted in intensive apple orchards located in the Turkestan region, known for its grey-brown soil. The climate in the study area was characterized as continental, with hot and dry summers and limited precipitation. Soil samples were analyzed for agrophysical and agrochemical properties, including nutrient levels and trace elements. The results showed that the control group had a decreasing trend in yield, while both the generally accepted program and the tailored nutrition program showed increasing trends in yield, with the latter showing a decrease in 2022. Over the fouryear period, the fruits from the control group exhibited reduced commercial qualities. Our program demonstrated similar sweetness and superior shape and yield compared to the conventional method. However, the storage quality of apples in our program was lower. Nevertheless, considering its positive impact on soil fertility and cost-effectiveness, our program appears to be an optimal choice. The findings of this study provide valuable insights into the effects of different nutrient management strategies on the growth, health, and productivity of apple trees in a garden setting. This information can benefit orchard growers and researchers seeking to optimize nutrient management practices for apple trees. The study also highlights the importance of considering various factors, such as orchard characteristics and environmental conditions, when designing nutrient management strategies for apple orchards.

Spatial phylogenetics of the flora in the Sierra Madre del Sur, Mexico: Evolutionary puzzles in tropical mountains

AbstractAimTo test explicitly whether the Sierra Madre del Sur includes areas with significant neo‐, paleo‐ and mixed endemism and to explore possible environmental drivers implied in their high species richness and spatial phylogenetic patterns.LocationSierra Madre del Sur, Mexico.TaxonVascular plants.MethodsSpecies richness, species endemism, phylogenetic diversity and phylogenetic endemism were analysed through a categorical analysis of neo‐ and paleo‐endemism for a set of 91493 unique records. Nonparametric Kruskal–Wallis tests for multiple comparisons of environmental variables among phylogenetic endemism categories were conducted.ResultsThe area includes 9524 species with 1133 endemics. The spatial distribution of species richness, endemism and phylogenetic metrics is heterogeneous. Species richness has a strong correlation with weighted endemism and weighted phylogenetic endemism. Neoendemism is mainly concentrated in the pine‐oak forest at higher elevations, paleo‐endemism in pine‐oak forest and seasonally dry tropical forest at lower elevations; mixed and super‐endemism were located in the cloud forest and its ecotones with the pine‐oak forest, tropical rain forest and seasonally dry tropical forest. The Kruskal–Wallis test showed significant differences only for elevation, precipitation and temperature.Main conclusionsThe Sierra Madre del Sur includes areas of neo‐, paleo‐ and mixed endemism heterogeneously distributed, representing an evolutionary puzzle of phylogenetic diversity promoted by environmental complexity. Recent diversification is suggested for areas of neoendemism, mainly in regions of pine‐oak forest and seasonally dry tropical forest, where elevation, seasonality and precipitation are variable. Areas of paleo‐ and mixed endemism indicate the preservation of ancient lineages in cloud forest and tropical forest. The Sierra Madre del Sur represents an intricate scenario for the diversification of Neotropical flora, with singular elements diverged in situ and others migrated and preserved in climatic and adaptative refugia through time.

Effect of multi parameter synergy on the upgrading characteristics of wide size moist coal

ABSTRACT Through composite dry separation, effective precipitation and impurity removal can be achieved, improving the quality of raw coal. This paper mainly systematically analyzes the synergistic control mechanisms of airflow velocity, airflow transition layer height and control angle on the upgrading characteristics of moist coal. The results show that Zone I is a high airflow area, and when v = 2.12 m/s, it can effectively destroy the original static stable structure of low-density particles, increase the degree of freedom of particle accumulation volume, and achieve effective precipitation of particles. Zone II is a medium air volume area, and when v = 1.78 m/s, the high-density particle group in this area has the weakest obstruction effect on airflow, which can achieve efficient particle precipitation. Zone III is a low airflow area, where the dispersion of high-density particle groups increases at v = 1.36 m/s. The airflow can effectively act on the particles through the bed layer, reducing their surface water. When the height (H) of the gas transition layer is 49-52 mm and the regulatory perspective is 20–25, the distribution uniformity of the gas flow in the bed is the best. After separation and upgrading, the moist coal concentrate yield is 78.3%, ash content is 10.05%, as well as the possible deviation E value is 0.1 g/cm3.

Importance in Shifting Circulation Patterns for Dry Season Moisture Sources in the Brazilian Amazon

AbstractWater is redistributed from evaporation sources to precipitation sinks through atmospheric moisture transport. In the Brazilian Amazon, the spatial and temporal variability of dry season moisture sources for key agricultural regions has not been investigated. This study investigates moisture sources for dry season rainfall in the state of Rondônia in Brazil, especially during drought years. Using a precipitationshed framework, we quantified the variability of moisture contributions to rainfall in the state of Rondônia (Brazilian Amazon) and the influence of synoptic circulation patterns. Ocean evaporation accounts for 58% of mean dry season precipitation while continental recycling contributed 42%. During drought years, although forests maintain or increase evapotranspiration, the moisture contribution of both ocean and forests to dry season rainfall decreases due to the synoptic circulation changes, reducing the moisture transport into Rondônia.

Probability of rainstorm and flood disasters due to extreme precipitation in Fen River Basin, China.

Analysis of the probability of extreme precipitation events leading to rainstorm and flood disasters can aid in disaster prevention policy development. Using daily precipitation data from 16 meteorological stations from 1960 to 2019, we calculated eight extreme precipitation indices to analyze the spatio-temporal characteristics of extreme precipitation in the Fen River Basin (FRB) through ensemble empirical mode decomposition and Kriging interpolation. Extreme precipitation events and disasters were defined based on a combination of the antecedent precipitation index (API) and extreme precipitation on the event day and classified; extreme precipitation and the API were ranked from small to large and classified into dry, wet, and moderate (mod) precipitation periods, respectively, yielding nine extreme precipitation event categories. The probability of disasters caused by different types of extreme precipitation events was calculated using a binomial distribution. The results are as follows: (1) between 1960 and 2019, except for extreme precipitation period length, which continuously increased, the extreme precipitation indices changed from a downward to an upward trend since the 1980s. All extreme precipitation indices showed similar interannual variation over short periods and different interdecadal variation over long periods. (2) The extreme precipitation indices showed latitudinal and zonal spatial divergence patterns, but different spatial characteristics were observed around the 1980s. (3) More than 70% of extreme precipitation events in the midstream and downstream fell into four categories: "dry-dry," "dry-mod," "mod-dry," and "mod-mod." (4) A single category VII (VIII) extreme precipitation event in the midstream (downstream) had a maximum probability of causing disaster of 14%. When more than four extreme precipitation events occurred in a year, the probability of one disaster was the highest and that of four or more disasters was < 0.1%. The probability of rainstorm and flood disasters increased gradually with increasing frequency of annual extreme precipitation events.

Ecological consequences of shifting habitat mosaics within and across years in an intermittent stream

Abstract Intermittent streams that cease to flow during dry periods represent more than half of the global river network, and are particularly common in arid and semi‐arid regions. They are characterised by high spatial and temporal variability in aquatic habitat, forming a shifting habitat mosaic that supports diverse assemblages of native and endemic species. Climate projections for much of the world predict greater variation in precipitation and increasing drought severity, suggesting a need to better understand species' responses to habitat variability within intermittent stream ecosystems. Here we explored changes in the distribution and abundance of aquatic vertebrates in response to a wide range of annual hydrologic conditions within a Mediterranean‐climate intermittent stream in California. We conducted wetted habitat and vertebrate abundance surveys during the dry season for 7 years, spanning both extreme wet and extreme dry annual precipitation conditions, and characterised the variation in the size, persistence, and spatial configuration of wetted habitats in relation to the observed abundance and composition of fishes, amphibians, and aquatic reptiles. We characterised the habitat mosaic using a k‐means clustering approach, and identified three habitat types with distinct size, persistence, and connectivity distributions. We found that some wetted habitat units persisted across all years, regardless of antecedent precipitation, whereas others dried in all but the wettest years. We determined that persistent pools, a subset of wetted habitats present in the stream, supported diverse assemblages of native species even during extreme dry conditions, while transient pools acted as important habitat for particular species and life stages, including a young‐of‐year minnow species. Linear mixed models indicated that species' abundances were influenced by habitat quantity, quality, and connectivity. Our study ‐ considers intermittent streams as shifting habitat mosaics and uses multi‐year surveys to understand the ecological consequences of habitat variability within and across years to advance our understanding of intermittent stream ecology and the implications of climate change for spatial and temporal patterns of refuge habitat.

Experimental Study on Humidification Coagulation and Removal of Fine Particles Using an Electrostatic Precipitator.

A wet electrostatic precipitator (WESP) has much higher capture rate for fine particulate matter, PM2.5, than a traditional dry type electrostatic precipitator does. In order to make full use of existing dust removal equipment and reduce the emissions of smoke and dust to zero, a combination of chemical coagulation and humidification coagulation is proposed using a WESP. The results show that the addition of chemical coagulant can promote the coagulation of coal-fired dust particles. After the addition of pectin (PG), the median diameter of dust particles increases from 28.19 μm to 45.28 μm. Water vapor humidification can promote the coagulation of dust particles. When the water vapor injection rate increases from 0 kg/h to 3.2 kg/h, the median diameter of dust particles increases from 28.19 μm to 36.45 μm. The synergistic effect of the coagulant and water vapor can enhance the chemical coagulation effect; when 1.0 × 10-2 g/L PG and 3.2 kg/h water vapor synergize, the collection efficiency reaches 98.17%, and when 1.0 × 10-2 g/L polyacrylamide (PAM) and 3.2 kg/h water vapor synergize, the collection efficiency reaches 96.68%. Both chemical coagulation and water vapor humidification can promote the condensation of coal dust, which is beneficial to improve the efficient capture of fine particles using WESP.

Recent growth increase in endemic Juglans boliviana from the tropical Andes

The spatial coverage of tree-ring chronologies in tropical South America is low compared to the extratropics, particularly in remote regions. Tree-ring dating from such tropical sites is limited by the generally weak temperature seasonality, complex coloration, and indistinct anatomical morphology in some tree species. As a result, there is a need to complement traditional methods of dendrochronology with innovative and independent approaches. Here, we supplement traditional tree-ring methods via the use of radiocarbon analyses to detect partial missing rings and/or false rings, and wood anatomical techniques to precisely delineate tree-ring boundaries. In so doing we present and confirm the annual periodicity of the first tree-ring width (TRW) chronology spanning from 1814 to 2017 for Juglans boliviana (‘nogal’), a tree species growing in a mid-elevation tropical moist forest in northern Bolivia. We collected 25 core samples and 4 cross-sections from living and recently harvested canopy-dominant trees, respectively. The sampled trees were growing in the Madidi National Park and had a mean age of 115 years old, with certain trees growing for over 200 years. Comparison of (residual and standard) TRW chronologies to monthly climate variables shows significant negative relationships to prior year May-August maximum temperatures (r = −0.54, p < 0.05) and positive relationships to dry season May-October precipitation (r = 0.60, p < 0.05) before the current year growing season. Additionally, the radial growth of Juglans boliviana shows a significant positive trend since 1979. Our findings describe a new and promising tree species for dendrochronology due to its longevity and highlight interdisciplinary techniques that can be used to expand the current tree-ring network in Bolivia and the greater South American tropics.

Examining moisture contribution for precipitation in response to climate change and anthropogenic factors in Hengduan Mountain Region, China

Climate change and anthropogenic factors have resulted in intense and frequent droughts and floods in the Hengduan Mountain Region (HMR). Exploring the source supply of evaporation and transportation processes for the precipitation in the HMR can help us understand regional precipitation characteristics and provide valuable insights regarding effective water resource management, disaster prevention, and mitigation. Based on the ERA5 reanalysis data, we identified the annual and seasonal precipitationsheds of the HMR, using the Water Accounting Model-2layer, to investigate the potential mechanisms that drive the changes in the precipitation in the HMR, in terms of external moisture contribution and local recycling. The identified precipitationshed in the HMR varied in response to different types of precipitation during the different seasons. The decrease in the annual precipitation was mainly attributed to the reduced moisture supply from the extended southwest (SW) and northwest (NW) regions, portraying a decreasing trend of −2.08 mm/yr/yr and −0.92 mm/yr/yr, respectively. The detected difference in the moisture sources and transport pathways, in terms of the response of wet and dry precipitation years, can improve our understanding of the moisture patterns of wet and dry years. We could conclude that the increase in moisture from the SW regions, due to El Niño, may have triggered the heavy precipitation in the HMR in 1998. Additionally, the reduction in moisture from the SW regions, due to La Niña, may have triggered an extreme drought in the HMR in 2011. Notably, woodland and water surface expansion tend to weaken local recycling (−0.07 %/yr) after 2000. In the future, the decreasing trend of local recycling will likely be intensified owing to large-scale artificial reservoir construction and the surface changes caused by underlying impoundment.

Evaluation of Changes in Dry and Wet Precipitation Extremes in Warmer Climates Using a Passive Water Vapor Modeling Approach

Abstract Hydroclimatic extremes, such as heavy daily rainfall and dry spells, are expected to intensify under anthropogenic warming. Often, these changes are diagnostically related to thermodynamic increases in humidity with warming. Here, we develop a framework that uses an online calculation of the thermodynamically induced changes of the full precipitation distribution with warming in an idealized moist atmospheric general circulation model. Two water vapor variables, the standard active one and an additional passive one (i.e., no latent heat release when condensation occurs), are advected by the resolved circulation. The passive water vapor is thermodynamically perturbed by modifying the saturation specific humidity used in the calculation of its condensation tendency and surface evaporation. The difference between the precipitation of the perturbed passive water vapor relative to the control one corresponds to the thermodynamic component of precipitation change, which can be evaluated for the entire distribution. Here, we evaluate wet and dry extremes. Our simulations have tropical increases and higher-latitude decreases of dry spell’s length (defined as the maximum consecutive dry days), as found in the zonal mean of comprehensive models. This simulated thermodynamically induced intensification of dry spells in the tropics arises from the decreased contrast between sea surface temperature and surface air temperature with warming. There is a simulated increase in heavy daily rainfall (e.g., the 99.9th percentile of the daily precipitation distribution) at all latitudes that differ modestly from a previous theory that assumes moist-adiabatic stratification. Consistent with this theory, increased warming aloft slightly dampens the simulated increase.

A Novel Hydro-Thermal Synthesis of Nano-Structured Molybdenum-Iron Intermetallic Alloys at Relatively Low Temperatures

Nano-structured Mo/Fe intermetallics were synthesized from precursors that contained 72/28% and 30/70% molar ratios of Mo/Fe, which were given as precursors A and B, respectively. These precursors were prepared from the co-precipitation of aqueous hot solutions of ammonium heptamolybdate tetrahydrate (AHM) and ferrous oxalate. The dry precipitates were thermally treated using TG-DSC to follow up their behavior during roasting, in an Ar atmosphere of up to 700 °C (10° K/min). The TG profile showed that 32.5% and 55.5% weight losses were measured from the thermal treatment of precursors A and B, respectively. The DSC heat flow profile showed the presence of endothermic peaks at 196.9 and 392.5-400 °C during the thermal decomposition of the AHM and ferrous oxalate, respectively. The exothermic peak that was detected at 427.5 °C was due to the production of nano-sized iron molybdate [Fe2(MoO4)3]. An XRD phase analysis indicated that iron molybdate was the only phase that was identified in precursor A, while iron molybdate and Fe2O3 were produced in precursor B. Compacts were made from the pressing of the nano-sized precursors, which were roasted at 500 °C for 3 h. The roasted compacts were isothermally reduced in H2 at 600-850 °C using microbalance, and the O2 weight loss that resulted from the reduction reactions was continuously recorded as a function of time. The influence of the reduction temperature and precursor composition on the reduction behavior of the precursors was studied and discussed. The partially and completely reduced compacts were examined with X-ray powder diffraction (XRD), a reflected light microscope (RLM), and a scanning electron microscope (SEM-EDS). Depending on the precursor composition, the reduction reactions of the [Fe2(MoO4)3] and Fe2O3 proceeded through the formation of intermediate lower oxides, prior to the production of the MO/Fe intermetallic alloys. Based on the intermediate phases that were identified and characterized at the early, intermediate, and final reduction degrees, chemical reaction equations were given to follow up the formation of the MoFe and MoFe3 intermetallic alloys. The mechanism of the reduction reactions was predicted from the apparent activation energy values (Ea) that were computed at the different reduction degrees. Moreover, mathematical formulations that were derived from the gas-solid reaction model were applied to confirm the reduction mechanisms, which were greatly dependent on the precursor composition and reduction temperature. However, it can be reported that nano-structured MoFe and MoFe3 intermetallic alloys can be successfully fabricated via a gas-solid reaction technique at lower temperatures.

Evaluating Dry and Wet Season Precipitation from Remotely Sensed Data Using Artificial Neural Networks for Floodplain Mapping in an Ungauged Watershed

This research creates a framework for modelling the rainfall-runoff process using satellite precipitation data and a floodplain map in ungauged urban watersheds. The combined effects of urbanisation and climate change over the past few decades have increased the number of flooding incidents. Accurate prediction of the flood-prone zone is crucial for policymakers and system managers to build the watershed's resilience during catastrophic flooding events. Precipitation and runoff data are crucial for hydraulic and hydrologic analysis and for identifying flood-prone areas. However, it is difficult to obtain precipitation and discharge data for hydrologic analysis in data-scarce regions. In this context, this research employs satellite precipitation products for rainfall-runoff analysis, which is subsequently utilised in a hydraulic model to delineate a flood-prone zone in an ungauged watershed. The Hydrologic Engineering Centre-River Analysis System (HEC-RAS) and Hydrologic Modelling System (HEC-HMS) models were utilised in the study region to simulate and analyse interactions between rainfall, runoff, and the extent of the flood zone. Setting up and calibrating the HEC-HMS model using a satellite precipitation product is required for the dry and wet seasons. For the wet and dry seasons, HEC-HMS gets validated with an R-square value of 0.72 and 0.85, respectively. Three types of simulations were conducted in the calibrated HEC-HMS model to create the hydrograph with 25-, 50-, and 100-year of rainfall return periods. Finally, the one dimensional HEC-RAS model generates a flood inundation map for the pertinent flooding occurrences from the acquired peak hydrograph. By comparing the values of the specified return periods, the produced flood map depicts the affected area during various return periods of flooding events and provides a quantifiable display of inundation extent percentage (IE%).

Short- and long-term forecasting for building energy consumption considering IPMVP recommendations, WEO and COP27 scenarios

Understanding and predicting power consumption behavior helps estimate costs, seek actions to save energy and plan affirmative actions that raise people's awareness. Organized civil society has made efforts in this context. Our contribution is a framework that first extracts knowledge about consumption through an extensive time series analysis of the building under study. Proper acquisition of meteorological (e. g. dry bulb temperature, humidity, solar radiation, and precipitation) and power consumption data are discussed. The correlation between these time series is verified, which develops knowledge about the problem. We believe forecasts will be more reliable using accurate models with more knowledge. Afterward, we forecast for the short-term period (hour, day and month-ahead) and long-term period (2030 and 2050), considering the scenarios proposed by the World Energy Outlook (WEO-2022) and Convention on Climate Change (COP27). Acquisition, processing, data analysis, as well as predictions, each framework step follows the International Performance Measurement and Verification Protocol (IPMVP-2022) recommendations. Building energy consumption forecasts considering IPMVP, WEO, and COP27 scenarios are originals in the literature. IEEE rigor for load measurement and modeling is achieved. Our study also follows the ISO:50000 energy efficiency purposes. The analysis and forecasting use data from a public building with an approximate circulation of 5,000 people per day. The objective is to contribute to a better understanding of building engineering to structure energy management actions. As stated at COP27: enough greenwashing talk, let us move on to smart actions.

Partitioning the Uncertainties in Compound Hot and Dry Precipitation, Soil Moisture, and Runoff Extremes Projections in CMIP6

AbstractA comprehensive assessment of compound hot and dry extremes based on different drought conditions (low precipitation, runoff, or soil moisture) and associated uncertainties is necessary to fully understand the possible risks. Here, we analyze changes in the likelihood of compound hot and dry conditions associated with low precipitation, runoff, and soil moisture using Coupled Model Intercomparison Project Phase6 (CMIP6) simulations for present‐day climate (+1°C) and additional global warming levels (+1.5°C, +2°C, +3°C). Further, we investigate the contributions of different components (e.g., global warming levels, climate models, copula types) to the total spread in their future projections. Results show the significance of global warming levels in governing risks of rising compound hot and dry extremes. The hotspot regions include the Mediterranean, South Central America, Amazonia, and Sahara. The rising risks are also accompanied by rising uncertainty as the spread in changing likelihood is significantly contributed by Earth System Models (ESMs), global warming levels, their interactions, and the statistical estimation error. The uncertainty due to ESMs spread was observed to be most significant in the case of compound hot and low soil moisture extremes, which also corresponds to some of the most impactful conditions. It was observed that the estimation error dominates the uncertainty in compound hot and low precipitation extremes as compared to the two other combinations. Our findings indicate that the regional likelihood and associated uncertainties of compound hot‐dry events in CMIP6 projections are functions of both the selection of drought types and the methodology of deriving the joint extremes.

Features of the mechanism of aerosol fractionation in solid hydrometeors

The object of the study is the dispersed fractions of an aerosol substance in the snow cover. At the sampling sites located in the middle taiga zone within the Mezen-Vychegoda Plain on a high terrace in the Sysola river valley, 3 km west of the city of Syktyvkar, fresh snow and surface frost were sampled. The analysis of the ratios in the surface hoarfrost of subdispersed fractions of the aerosol substance was carried out in conjunction with the granulometric analysis of freshly fallen snow. Studies using the method of dynamic light scattering of the granulometric composition of an aerosol substance in freshly fallen snow and surface hoarfrost formed between snowfalls showed that a bimodal distribution of particles is recorded in all snow samples. At the same time, the distribution of submicron aerosol particles in frost samples is already characterized by the presence of three modes. Also, with an increase in the duration of the period between snowfalls in hoarfrost samples, a redistribution of particles between fine and medium fractions is observed in the direction of a significant increase in particles in the fine fraction, but the volume concentration of particles of the large fraction changes slightly. It is assumed that the identified circumstance is associated with the action of capillary forces and the adhesion of dry precipitation during the crystal formation of hoarfrost (it is proposed to call this phenomenon "frosty condensation"). A similar effect was also observed in the West Siberian southern taiga and the coastal tundra of the Lower Pechora region.

Assessing the Feasibility of Rooftop Rainwater Harvesting for Food Production in Northwestern Arizona on the Hualapai Indian Reservation

With the uncertainties of climate change and the persistence of droughts in the Southwestern US, finding additional renewable water resources is crucial to ensure safe drinking water and attain food security in rural and tribal communities. Rainwater harvesting (RWH), the practice of centralizing, collecting, and storing rainwater for later use, has the potential to help alleviate some water stresses in these communities. Although RWH is not a new concept, it has not been widely practiced in arid and semi-arid environments in the United States. This study assessed the feasibility of rooftop RHW at a small scale, in Peach Springs, Arizona, on the Hualapai Indian Reservation. Working alongside the Federally Recognized Tribal Extension Program (FRTEP) agent for the Hualapai Tribe, this study considered RWH from four prospective buildings to supplement irrigation practices for food production. Due to high standard deviation and coefficient of variation values, annual precipitation amounts were classified into normal, dry, and wet years to assess variability over the last 40 water years. An average total of ~29,285 L could be collected from one of the buildings considered for RWH during the growing season of April to September during a classified normal year. The Food and Agriculture Organization’s (FAO) AquaCrop model was used to determine the area that can be cultivated with four staple crops, maize, tomatoes, dry beans, and sunflowers, which are currently being grown in the community garden, solely using the captured rainwater. Cultivable areas range from 8.7 m2 to 71 m2 depending on the catchment size, crop, and classified precipitation year—a wet, dry, or normal precipitation year. A total of 81.2 kg of dry corn could be harvested during a normal precipitation year, solely using the collected rainwater from one of the buildings.

Low-Temperature Decomposition of Nitrous Oxide on Cs/MexCo3−xO4 (Me: Ni or Mg, x = 0–0.9) Oxides

Mixed oxides MexCo3−xO4 (Me: Ni or Mg, x = 0–0.9) with a spinel structure were synthesized by precipitation from Me, Co nitrate solutions using (NH4)2CO3 as the precipitating agent with subsequent modification of the dry precipitate with cesium by the Pechini method and calcination. The samples were studied by XRD, TPR, and TPD methods. Their catalytic activity was studied in the low-temperature (150–350 °C) nitrous oxide decomposition process. It was shown that an increase in the degree of substitution of cobalt (x) leads to a significant decrease in the degree of crystallization of the oxides, an increase in the specific surface area, and the formation of surface weakly bound oxygen species. The highest activity was shown by the catalysts with a degree of substitution x = 0.1, especially by the nickel-substituted sample, which contained the maximum amount of weakly bound surface oxygen species. The difference in the influence of Mg and Ni on the MexCo3−xO4 properties is discussed.

OPTIMIZATION OF ALKALINE–THERMAL HYDROLYSIS TO OBTAIN STRUVITE FROM DIGESTED SLUDGE USING A BOX–BEHNKEN DESIGN: SOLUBILIZATION OF NUTRIENTS AND METALS

In this study, we investigated ways by which to optimize metals and nutrients solubilization from sewage sludge using alkaline–thermal hydrolysis and the Box–Behnken design. We also examined through struvite crystallization the recovery of solubilized nutrients from hydrolyzed liquid and determined the effect of NaOH concentration, the liquid/solid ratio, and temperature on the hydrolysis process. Nutrients solubilization was positively affected by decreasing liquid/sludge ratio and increasing NaOH concentration. Ca, Al, and Zn solubilization increased with increasing temperature. The optimum condition for solubilization of nutrients and metals was 0.7 M NaOH and a 5/1 mL/g liquid/solid ratio at 35 °C. EDS analyses of hydrolyzed sludge obtained under optimum conditions showed that the mass percentage of C, P, Fe, Al, and K decreased compared to that of the digested sludge. Under optimum conditions, the removal efficiencies of NH4+ and PO43- from hydrolyzed liquid by struvite precipitation were 57.43 and 79.22% at a N:Mg:P molar ratio of 1:1:1, and 73.31 and 99.02% at a N:Mg:P molar ratio of 1:1.5:1, respectively. XRD analyses of the dry precipitate showed hazenite in addition to struvite formation at a molar ratio of N:Mg:P of 1:1:1.

Climate change has limited effect on the growth of Afzelia africana Sm. and Anogeissus leiocarpus (DC.) Guill. and Perr. in riparian forests in the savannas of Ghana

Abstract The growth of trees in riparian forests in semi-arid savannas is resilient to the natural variations in temperature and precipitation due to the availability of riverine water. Climate change can nevertheless, intensify the evapotranspiration of tree species, altering biodiversity, plant productivity and ecosystem services. Understanding the growth response of riparian tree species to climate change is, therefore, critical for their management and conservation. Here, we used 23 cross-dated stem discs of Anogeissus leiocarpus (DC.) Guill. and Perr. and Afzelia africana Sm. randomly sampled from riparian forests in the humid and dry savanna regions of Ghana to assess their growth response to climate change. A generalized additive mixed model (GAMM) was used to integrate species-specific basal area increments to an array of explanatory variables that may affect growth, including tree size and seasonal temperature and precipitation between 1982 and 2013. We observed significant association between tree size, rainy and dry season temperatures and precipitation variables, and changes in tree growth. Despite the strong fluctuations in tree growth over time, the estimated growth rates of the species from the residuals of the GAMMs showed no significant change in growth. Our findings suggest that these riparian forests are highly resistant to weather extremes and therefore, might persist (up to a certain point) even if climate change continues to intensify.

Evaluating homogeneity and trends in extreme daily precipitation indices in a semiarid region of Brazil

A regional investigation of precipitation extremes could help the local authorities to develop strategies against potential climatic disasters, especially in regions of large climate vulnerability. In this context, this study focused on the homogeneity and trend analysis of eleven extreme precipitation indices from a daily rainfall dataset of rain gauges of the state of Ceará, located in the north of Northeast Brazil, from 1974 to 2018 at annual and seasonal time scales. The data were first submitted to gap-filling and quality control processes. Homogeneity, trend, and correlation coefficient were performed subsequently. Homogeneity results showed that most of the precipitation series were classified as “useful.” Significant break years in the series agreed well with moderate and very strong El Niño and La Niña events, suggesting a further investigation of this possible connection. Wet and dry day precipitation indices mainly indicated a decrease in the rainfall regime and an increase in dry days, mainly in the central-eastern, northwestern, and southern regions of the Ceará, especially during the annual time scale and the rainy season. The Locally Weighted Scatterplot Smoothing (LOWESS) curve showed changes in almost all series during the 1980s and 1990s, coinciding with the homogeneity breaks and years of severe droughts that strongly hit the region. Correlation coefficients were strong and significant between rainfall total index and the other precipitation indices.