Dry Tropical Climate Research Articles

An Investigation into the Effects of Varying Seasons, Indole-3-Butyric Acid (IBA) and Rooting Media on the Rooting and Longevity of Air-layered Water Apples (Syzygium samarangense L.)

Background: The variation observed in sexual propagation often results in slow growth and fruit development, attributed partly to insufficient photosynthates during early growth stages. To address this challenge, vegetative propagation methods such as air layering offer promising solutions. This technique not only accelerates productivity but also enhances the quality of water apples. Recognizing the importance of air layering in water apple cultivation, this experiment was conducted to standardize this technique by examining the impact of different seasons and planting media in the western tropical wet and dry climate of Tamil Nadu. Methods: The study was conducted to evaluate the variables affecting air layering in water apples in Coimbatore district. The experiment was carried out with three different factors like seasons [August (S1), September (S2) and October (S3)] and IBA [applied at different concentrations of 2000 mg/L (I1), 3000 mg/L (I2) and 4000 mg/L (I3)] along with different rooting media: Cocopeat (M1) and Sphagnum moss (M2). The factorial randomized complete block design (FRCBD) was laid out for statistical analysis. Result: Sphagnum moss performed as a better rooting medium due to its high water holding capacity and good aeration. Increase in the number and early formation of roots were due to more rain fall and high relative humidity in August, that resulted in more nutrient uptake and structural stability. The discovery aids in determining the optimal conditions, including season, dosage and combination (4000 mg/L IBA with sphagnum moss applied in August), for successful air layering in water apple.

Land Use affects the Soil Aggregation Pattern during Restoration of Degraded Land under Tropical Dry Climate

Soil aggregate formation and stability are crucial in safeguarding soil carbon pools, as they form the basic unit of soil structure in terrestrial ecosystems. The impact of different land uses on soil aggregation pattern has widely been studied but is limited under tropical dry climate conditions. This study aimed to determine the soil aggregation pattern at two soil depths (0-15 cm and 15-30cm) in three different plantations (Peltophorum pterocarpum, Eucalyptus globulus, and Acacia nilotica) established in degraded land under tropical dry climate. The soil aggregates were categorized into microaggregate, mesoaggregate and macroaggregate based on their size fractions which were determined by the wet sieving method. The percent of macroaggregate, mesoaggregate, and microaggregate fractions at 0-15 cm depth ranged from 62.2 – 82.6%, 31.6 – 36.7%, and 1.1 – 4.9 % respectively whereas at 15-30 cm depth, it ranged from 69.7 - 81.7%, 17.1 - 31.6%, and 1.2 - 2.8%. The mean weight diameter values at 0-15 cm and 15-30 cm soil depth ranged from 2.27-3.37mm and 2.85-3.35 mm respectively. The higher percentage of macroaggregate fractions in Peltophorum pterocarpum plantation compared to Eucalyptus globulus, and Acacia nilotica plantations indicated that the Peltophorum pterocarpum plantation has slightly more potential to improve aggregate formation and soil structure in the degraded lands under tropical dry climate. In addition, appropriate land use practices can increase soil aggregate stability in the study area.

Simple hydrological models for assessing the impact of forest cover change on streamflow for large catchments with a dry tropical climate

ABSTRACT Hydrological models are widely used to assess the impact of climate variability and land use change on streamflow. However, it is uncertain whether these models are capable of simulating the impact given parameter interactions and inter-annual climate variability for large dry catchments. Two such catchments with extensive land clearing were selected to test three models – AWBM, Sacramento and SimHyd – in terms of their capacity to simulate streamflow during periods of vastly different levels of forest cover. AWBM outperformed others, and thus was further simplified as AWBM_C a with minimum performance deterioration to have only one transferable parameter: the average storage capacity, C a. A reduction of 21–28% in the C a value for the post-clearing period indicates a decrease in the amount of water stored for transpiration and consequently an increase in runoff-generation capacity. AWBM_C a can be used to predict the impact of forest cover change on streamflow with different C a values.

Rain Attenuation Prediction at Different Time Percentages for Ku, K, and Ka Bands Satellite Communication Systems over Nigeria

This paper evaluates the influence of rainfall on propagated signal at different time exceedance percentages of an average year, over the climate zones of the country. Specifically, it demonstrates critical and non critical signal fade or signal outage time exceedance (0.001% to 1%) for Ku, K, and Ka-band systems in an average year. The study was carried out using meteorological data made available by the Nigerian Meteorological Agency (NiMet) over a period of 10 years (2009–2018). The four climate zones in the country were represented by five (5) locations; Maidugiri (warm desert climate), Sokoto (tropical dry climate), Port Harcourt (tropical monsoon climate), Abuja and Enugu (tropical savanna climate). The parameters were simulated into the International Telecommunications Union Recommended (ITU-R) models for rain attenuation over the tropics and results presented using MatLab and Origin Lab. Results of Ku band propagations showed that only locations in the tropical savanna and tropical monsoon climates experienced total signal outage for time percentage exceedance equal to or below 0.01% for both horizontal and vertical polarizations. At K band propagations, the five locations showed to have experienced signal outage at time exceedance equal to and below 0.01%, almost same was recorded for the Ka-band propagation. It was also observed that horizontal and vertical polarization of signal had slightly different rain attenuation values for the studied bands at the five locations, with horizontal polarization having higher values than vertical polarization.

Study of The Influence of Storage Media on the Thermo-mechanical Behavior of Concrete and Cement Blocks

Once all construction materials have been formulated, it is necessary to find a suitable environment in which to store them before using them in the building. Generally speaking, in developing countries, materials are not preserved under the real conditions of temperature and humidity and are exposed to often severe climatic conditions. This has an impact on the behaviour of these materials. With this in mind, we conducted our study on concrete and cement bricks, the two materials most commonly used in building construction in Africa. The overall objective of our study is to analyse the effect of storage environments, particularly ambient conditions of temperature and hygrometry, on the thermal and mechanical properties of concrete and cement bricks in a dry tropical climate. To achieve this objective, we first analysed the quality of the materials used to formulate the concrete and cinder block samples. Next, we chose a formulation method that would enable us to obtain the optimum proportions of aggregates. Finally, the thermal and mechanical parameters were measured using the KD2-Pro device and a mechanical press, respectively. The concrete and cinder block samples were stored for 28 days and 10 days respectively in the open air under ambient climatic conditions (35°C on average),in a water tank (29°C on average) and in a climatic chamber (20°C and 53% relative humidity). Results ranged from 1.126 (± 0.003) to 1.289 (± 0.023) W.m-1. K-1 for thermal conductivity. Mechanical test results ranged from 3.93 (±0.45) to 4.13 (±0.27) MPa for flexural strength and 16.42 (±0.17) to 17.95 (±0.21) MPa for compressive strength. The lowest thermal conductivity was obtained in the climatic chamber, with a value of 1.126(±0.0032)W.m-1.K-1.The best compressive strength of concrete and the best flexural strength of cement blocks were obtained for samples stored in the climatic chamber. For the best mechanical and thermal behaviour of these two materials, we recommend a temperature not exceeding 20°C as the storage environment in a dry tropical climate.

Rainwater harvesting and its efficient utilization in mandarin (Citrus reticulata Blanco) orchards under a dry sub-humid tropical climate

Abstract Water stress is a major factor affecting the productivity of citrus. Conservation and efficient use of rainfall–runoff may be an option for sustainable citriculture in water-scarce regions. A study, therefore, was conducted to evaluate the techno-economic feasibility of rainwater management strategies in citrus orchards of a water-scarce region of central India. The following three management strategies, namely (1) a continuous trench between plant rows (CTPR), (2) CTPR + rain water harvesting tank (RWHT)-based surface irrigation (IS), and (3) CTPR + RWHT-based solar-powered drip irrigation (ISD) were compared with rain-fed treatment (RFT) in citrus. Annually, CTPR + RWHT-based ISD conserved 4,556 m3 water ha−1, and resulted in higher fruit yield (219%), water productivity (85%), net profit (298%), net economic water productivity (130%), sustainable yield index (49%) and energy use efficiency (87%) compared with the RFT (fruit yield, 7.14 t ha−1; water productivity, 1.88 kg m−3; net profit, INR 59,704 ha−1; net economic water productivity, INR 15.75 m−3; sustainable yield index, 0.59; energy use efficiency,1.02 MJt−1) in citrus. The water balance of WHT indicated that 47% of harvested water could be utilized for irrigation in orchards. Overall, efficient rainwater management is suggested for citrus cultivation in water-scarce regions.

Optimisation of Thermal Comfort of Building in a Hot and Dry Tropical Climate: A Comparative Approach between Compressed Earth/Concrete Block Envelopes

Optimisation of Thermal Comfort of Building in a Hot and Dry Tropical Climate: A Comparative Approach between Compressed Earth/Concrete Block Envelopes

Palynofloral Change Through the Paleocene‐Eocene Thermal Maximum in the Bighorn Basin, Wyoming

AbstractTo better understand the effect of the Paleocene‐Eocene Thermal Maximum (PETM) on continental ecosystems, we studied 40 new palynological samples from the Bighorn Basin (BHB), northwestern Wyoming, USA. We see palm and fern abundances increase in the last 20–40 ka of the Paleocene, then dramatically with the onset of the carbon isotope excursion (CIE) defining the base of the PETM. Palynomorphs of plant groups with modern temperate climate distributions are absent from the CIE body, and this is when tropical plants are most diverse and abundant. During the CIE recovery, pollen of mesophytic/wetland plants become more common while tropical taxa persist. In the post‐CIE early Eocene tropical taxa are rare and temperate forms abundant, similar to the late but not latest Paleocene. Changes in the palynoflora are more easily detected if reworked palynomorphs are removed from analyses. We interpret palynofloral changes to indicate warming in the latest Paleocene, rapid warming and drying with the CIE onset, dry tropical climates through the CIE body, a return to wetter floodplains during a very warm CIE recovery, and cooler wet conditions in the post‐PETM early Eocene. These inferences are consistent with geochemical and paleobotanical proxies. Strikingly similar patterns in the palynoflora and megaflora suggest changes in vegetation were a basin‐wide phenomenon. These rapid, climatically forced changes in floral composition occurred without major extinction, perhaps indicating nearby refugia in which plants adapted to cooler and wetter climates persisted through the PETM.

Literature review: The effect of environmental arrangement on malaria incidence in dry tropical climate areas in NTT

"Indonesia Bebas Malaria 2030" is the Indonesian government's target proclaimed by the Indonesian Ministry of Health at this time. This set target is inversely proportional to several discoveries found in eastern Indonesia, especially East Nusa Tenggara. For example, in 2022 in Sikka Regency, there will be an increase in malaria cases reaching 55 people. Based on research conducted in Africa, it is known that the treatment of malaria can not only be overcome by medication but by improving the physical environment such as housing and the surrounding environment. Therefore, an article search was carried out in several reputable journals for the past ten years to determine the influence of external and internal environmental settings on the incidence of malaria, especially in the East Nusa Tenggara region. From the search that has been done, it is known that environmental factors provide and biological factors are the factors that most influence the thermal characteristics of the incidence of malaria in NTT.

Study of the influence of local materials insulation on cooling loads of a house made of breeze block or laterite in a dry tropical climate

In this paper, we study the influence of local materials for insulating roof and fiber-reinforced mortar coatings on cooling loads of a home in dry tropical climate. The wall of the housing is made of cinderblock or laterite and the insulating material of a roof panel is made with lime (24%), cement (6%), water (50%) of vegetable fibers hibiscus sabdariffa (16%), tree widespread in Burkina Faso and sugar cane bagasse (4%). This panel roof insulation and the fiber-reinforced mortar were characterized at the Laboratory of Physics and Chemistry of the environment by the hot plate method. The building is modeled in TRNSYS using climate data from the city of Ouagadougou. The results obtained show that in the warmer months of the year, that is to say in March and April, the relative differences between heat gains configurations the configurations “breeze block-coating mortar and roof not insulated” and ‘laterite- fiber-reinforced mortar coating and insulated roof’ vary between 15.6 % and 16.8 %. Configuration ‘laterite- fiber-reinforced mortar coating and insulated roof allows a reduction of annual heat gains of 15.5% compared to the configuration ‘breeze block-coating mortar and roof not insulated’.

Thermal performances of a bioclimatic building in hot and dry tropical climate

This paper is concerned with the thermal comfort of a double-walls seven stories bioclimatic building built with local construction materials. First of all, we use a numerical code to investigate the construction materials thermal inertia effects on the optimization of the building envelop. Second, the outer and inner surface temperatures are determined utilizing the TRNSYS code. A system of trap is then design to evacuate during nighttimes, the stored daily heat. The conditioned air thermal load differences between the double and simple walls are also investigated. Similarly, the linear thermal loss coefficients and the thermal bridge losses are computed utilizing respectively the ‘Heat’ software and the Degree Day method. The results show a difference of 6 to 7 oC between the outer and the inner maxima surface temperatures. The computation of the conditioned air thermal load indicates a net energy gain of the order of 5.8 % in the office spaces and 12.1% in the bedrooms, respectively for the double and simple walls. The double-walls thermal bridge losses amount to 16.46 % of the total building losses and 20.77 % for the 20 cm thick simple wall. The building envelop optimisation process continues with the study of the effects of the addition of a garden roof on the thermal comfort.

Impact of indoor heat load and natural ventilation on thermal comfort of radiant cooling system: An experimental study

Construction and operation of buildings are responsible for about 20% of the global energy consumption. The embodied energy of conventional buildings is high due to the utilization of energy-intensive construction materials and traditional construction methodology. Higher operational energy is attributed to the usage of power-consuming conventional air-conditioning systems. Therefore, moving to an energy-efficient cooling technology and eco-friendly building material can lead to significant energy savings and CO2 emission reduction. In the present study, an energy-efficient thermally activated building system (TABS) is integrated with glass fiber reinforced gypsum (GFRG), an eco-friendly building material. The proposed hybrid system is termed the thermally activated glass fiber reinforced gypsum (TAGFRG) system. This system is not only energy-efficient and eco-friendly but also provides better thermal comfort. An experimental room with a TAGFRG roof is constructed on the premises of the Indian Institute of Technology Madras (IITM), Chennai, located in a tropical wet and dry climate zone. The influence of indoor sensible heat load and the impact of natural ventilation on the thermal comfort of the TAGFRG system are investigated. An increase in internal heat load from 400 to 700 W deteriorates the thermal comfort of the indoor space. This is evident from the increases in operative temperatures from 29.8 to 31.5 °C and the predicted percentage of dissatisfaction from 44.5% to 80.9%. Natural ventilation increases the diurnal fluctuation of indoor air temperature by 1.6 and 1.9 °C for with and without cooling cases, respectively. It reduces the maximum indoor CO2 concentration from 912 to 393 ppm.

Thermal Comfort and Microclimate in Indoor Spaces of Low-rise Residential Buildings in Dry Tropical Climate

The aim of this research is to analyze thermal comfort and microclimate for indoor spaces in low-rise residential buildings in dry tropical climate. The study area is the municipality of Palmar de Varela in northern Colombia. The experimental methodology is based on measuring three microclimatic parameters: air temperature (Ta), relative humidity (RH) and natural ventilation (W). The study assessed the thermal sensation in indoor spaces based on Thermal Sensation Vote (TSV) and Predicted mean vote (PMV). Data gathered from surveys were analyzed with data mining technologies. The findings suggest that suspended ceilings and ceramic tiles aid to the thermal equilibrium of the building, resulting in a 1.1 °C decrease in indoor air temperature. Likewise, the correlation between temperature and wind (r = -0.72; -0.56) indicates that natural ventilation in buildings can alleviate thermal discomfort. Based on the thermal sensation evaluation, the predominant feeling reported by interviewees in indoor spaces was warm (2) in S1 and S2, and slightly warm (1) in S3. In addition, the correlation between air temperature and comfort sensation in indoor spaces (r = 0.64; 0.44) suggests that temperature has a direct impact on thermal sensation votes.

The Potential for Underutilized Fruits of Northern India to Improve Food Security and their Role in Climate Resilient- A Review

Underutilized fruits or less known fruits are the storehouse of nutrition and can play an important role in providing food security to people. As the name indicates underutilized fruits are those fruits which are neglected and rarely eaten. However, these fruits are rich in carbohydrates, fats, proteins, energy, vitamins, folic acids and dietary fibers. Since the dawn of time, these fruits have also been employed in Ayurvedic and Unani medicine for their medicinal properties. Due to the lack of outstanding flavor and attractive color, their consumption is quite low. The majority of these fruits have not gone through any domestication or selection processes. Their cultivation is extremely limited, and they primarily grow in the wild. These fruit species are appropriate for cultivation in disaster and drought-prone locations because of their resistance to biotic and abiotic challenges. The resistance genes present in these fruits can be utilized for the crop improvement program. In India, these fruits are mainly grown in a tropical wet and dry climate and also has importance in marginal land. To meet the nutritional needs of the expanding population, these fruits need to be domesticated and commercially grown. The cultivation of these fruits, which are a significant source of medicinal benefits, might assist in returning to the Ayurveda approach of treating various illnesses.

Relationships amongst water and sediment qualities, discharge, and allochthonous inputs of intermittent streams in tropical dry climates: Implications on stream management

Relationships amongst water and sediment qualities, discharge, and allochthonous inputs of intermittent streams in tropical dry climates: Implications on stream management

A new model of bauxitization in quartzitic landscapes: A case study from the Southern Espinhaço Range (Brazil)

AbstractLithology plays a fundamental role in rock weathering and erosion, and in landscape evolution. When weathering‐ and erosion‐prone lithologies are protected from erosion by more resilient rock types (e.g., quartzites and banded iron formations) unusual weathering products result. At the Southern Espinhaço Range, Minas Gerais, Brazil, bauxitic weathering profiles are found in a unique geomorphological–lithological–climatic setting. Resistant quartzites acted as a barrier against erosion of interbedded hematite‐phyllite lenses, channelling solution flows and facilitating the formation of deep weathering profiles. The long‐term exposure of the hematite‐phyllites under alternating wet and dry tropical climates favoured widespread bauxitization. Here we investigate the geochemical, mineralogical, geochronological and micromorphological signatures of scaffolded bauxites in order to reconstruct their evolutionary history. Our data suggest that recurrent aluminium and iron mobilization within the profiles were mainly driven by mineral dissolution‐reprecipitation mediated by bioturbation and the influx of vegetation‐derived organic species. (U–Th)/He geochronology of Al‐goethite reveals that bauxitization started at least since the Lower Miocene, with important intensification of weathering in the Upper Miocene and Lower Pleistocene. The adjacent resilient quartzites acted as scaffolds for bauxitization and supported the preservation of more erodible weathering profiles developed over phyllites. Surface waters that could not infiltrate into the impermeable adjacent quartzites preferentially infiltrated into the more weathereable phyllites, enhancing their porosity and permeability, further enhancing weathering. The evolutionary history of Southern Espinhaço Range bauxites suggests a new model of bauxitization in ancient land surfaces evolution underlain by quartzites, where erosion‐prone lithologies are scaffolded by resilient quartzites and survive long‐term weathering with minimum erosion, producing bauxites.

Long-term performance of grid-integrated solar photovoltaic system on institutional buildings in tropical wet and dry climates of India - a practical study.

This study presents a long-term performance analysis of a one-mega-watt power grid-connected PV plant installed on the rooftop of GITAM University,Visakhapatnam,Andhra Pradesh, India for 3 years. The 1000 kWp PV plant design, performance analysis, economic feasibility, and greenhouse gas reduction are provided. For 3 consecutive years (2018-2019, 2019-2020 and 2020-2021), the energy yields, performance ratio (PR), capacity utilisation factor (CUF) and efficiency are evaluated. The plant was established in 2018 with a peak power of 1000 kWp. The system feeds the state grid with all of the electricity it produces. The system is continuously monitored and analysed using yield, efficiency and performance parameters for 36 months (September 2018 to August 2021). Solar irradiation data has been collected from the National Renewable Energy Laboratory (NREL) database for these years. The system comprises 3078 PV modules, 23 inverters rating 20 kW/50 kW, a data logger and a Net-metering unit. The annual energy generation of the PV plant recorded during the study period is 1376.29 MWh, 1265.541 MWh and 1115.73 MWh. The annual average performance ratio for the first three consecutive years is observed as 0.68, 0.62 and 0.58, whereas the yearly average capacity factors are 15.5%, 14.11% and 12.72%, respectively. The overall system efficiency of the PV system during the study period is 11.39%. Compared to the country's current conventional thermal power plants, we predict that rooftop PV systems may reduce CO2 emissions by 2145.406 tCO2eq for the base year, based on the electricity produced by this PV plant. The grid-integrated photovoltaic plant in this study is compared to other systems in the literature for performance assessment.

The use of explanatory statistics for mapping groundwater potential zones in a semiarid area: Case of the Waddai province, eastern Chad

In Waddaï province, Eastern Chad, the dry tropical climate of the Sahel region causes a scarcity of surface water resources in the area. To respond to the growing demand on this vital element, and to preserve the social, economic and political stability, several groundwater (GW) exploration programs have been conducted in the previous decades. Of the few thousands of boreholes executed at the province of Waddaï, most fail to find GW reservoirs due to a lack of GW potential maps. In this study we try to fill this knowledge gap using Frequency Ratio (FR) and Weight of Evidence (WoE) techniques. The position of successful wells was used to train the statistical analysis methods and validate the models, while a total of nine topographic, geological and environmental factors were chosen as predictive variables. Results showed that the Southern and central parts of the province have greater potential for the presence of GW. This disposition was shown to be mainly controlled by lithology and slope, where flat areas dominated by unconsolidated alluvial deposits favour infiltration while rocky steep terrains favour surface flow. In comparison to the only previous study recently published, which used and expert opinion Multi-Criteria Decision-Making and Analytical Hierarchical Process based approach for the same purposes, some contradictions with the FR and WoE were observed in some predictive variable class weights, especially regarding lineament density and drainage density. This shows that, in areas where hydrogeological mechanisms and processes are not well understood, it is risky to rely on theoretical simplifying assumptions which are not always true.

Analysis of various degradations of five years aged mono c-Si, poly c-Si, and thin-film photovoltaic modules from rooftop solar installations in Dhaka’s tropical wet and dry climate conditions

This study evaluates the degradation of mono, poly, and thin-film silicon solar photovoltaic (PV) modules through visual and electrical measurements in Dhaka’s tropical wet and dry climate conditions. For this, several sites of rooftop solar PV installations in Dhaka, aged at least 5 years, were selected for field investigation. A visible inspection for visual degradation followed by experimental testing on various electrical characteristics of the PV modules installed on the rooftop using a portable Seaward I–V Tracer for measuring the electrical degradation was done. The electrical data were used to evaluate the degradation of short circuit current, open circuit voltage, fill factor, and maximum power in the field as compared to the nameplate values. Experimental results showed the varying types of visual degradation types such as visible cracks, snail trails, moisture intrusion, front glass, and discoloration for the investigated PV modules. The degradation of PV modules in terms of short circuit current was 0.7%/year for 85Wp mono c-Si, 7.6%/year for 150Wp poly c-Si, and 9.7%/year for 105Wp silicon thin-film, respectively. We believe this study would guide the maintenance of the solar PV systems installed on Dhaka city’s rooftop buildings.

Diversity and prevalence of gastrointestinal helminths of free-roaming dogs on coastal beaches in Ecuador: Potential for zoonotic transmission.

Free-roaming dogs are highly exposed to a range of zoonotic parasites, including helminths, which can be transmitted to humans, particularly in rural tropical settings of developing countries. To evidence the diversity and prevalence of gastrointestinal helminths in the stools of free-roaming dogs on the public Pacific coastal beaches of Ecuador, a cross-sectional study was conducted from August 2021 to August 2022. The sampling beaches are located along the tropical Pacific coastal region. Stools were collected from the ground in containers with 10% formalin and processed using the Ritchie method; eggs were identified under a microscope. A total of 573 stools were examined from 20 beaches; the overall prevalence was 157 (27.4%) for one or more helminths. Ten parasites were identified, nine of which are potentially zoonotic. Ancylostoma spp. was the most prevalent (19.4%), followed by Toxocara spp. (7.2%). Trichuris spp., Dipylidium caninum, Diphyllobothrium spp., Capillaria spp., Dicrocoelium spp., Heterobilharzia americana, Hymenolepis spp. and Spirocerca spp. were also observed. Five of them are reported for the first-time infecting dogs in Ecuador. Hence, we evidenced that Ecuadorian beaches are highly contaminated with the dogs' zoonotic gastrointestinal helminths, posing a great risk to public health. Differences in the presence and prevalence were found in samples of tropical humid and dry climate zones. Therefore, based on our findings, we encourage the implementation of broad antiparasitic treatment and prevention strategies to reduce the zoonotic risk.