Nighttime Temperatures Research Articles

An alternative nighttime radiative cooling paint using glass microspheres in water-based acrylic paint

An alternative method for producing radiative cooling paint using sustainable and cost-effective green materials, which can significantly reduce indoor temperatures. Prior research on radiative cooling systems revealed that multilayer metal oxide systems require expensive raw materials and high-end facilities, limiting large-scale production. Therefore, this study aimed to identify optimal conditions for producing radiative cooling paint using commercial spherical glass microspheres and titanium dioxide nanoparticles. The study investigated the effect of glass microsphere size, quantity, and coating thickness on emissivity and light reflectance. Results showed that glass microsphere size did not significantly affect emissivity. However, increasing coating thickness and glass microsphere quantity initially increased emissivity but stabilized at saturation points. The addition of glass microspheres decreased light reflectance, increasing temperatures during the daytime. The radiative cooling efficiency of the paint was tested, and the results showed that the glass microsphere content significantly affected the reduction in daytime temperatures. A mixture content of 45 and 75 wt% reduced the temperature by 2.96 and 3.09 °C, respectively, lower than the ambient temperature during the nighttime. The double layer of titanium dioxide/glass microspheres paint was more effective at cooling than the single layer of 45% glass microspheres, despite similar emissivity values. HIGHLIGHTS Commercial spherical glass microspheres and titanium dioxide nanoparticles are used as raw materials. Glass microsphere quantity and coating thickness are found to affect emissivity and light reflectance. A mixture of 45 and 75wt% glass microsphere content is shown to significantly reduce nighttime temperatures. Double layer paint is more effective at cooling than single layer paint despite similar emissivity values. GRAPHICAL ABSTRACT

What is a heat(wave)? An interdisciplinary perspective

Excessive summer heat is becoming people’s daily reality creating an urgency to understand heatwaves and their consequences better. This article suggests an interdisciplinary analytical framework of heat(waves) as multiple objects. It brings together data and perspectives from social anthropology, sociology, climate science, epidemiology, and meteorology to map the gaps in knowledge about heat(waves) and their impacts on one of the most vulnerable groups: older adults. Based on research in Poland and Spain, we look at heat(waves) as simultaneously individual experiences, biophysical changes, and socio-political phenomena. Climatologists and meteorologists define heat(waves) as prolonged episodes of abnormally high temperatures. Epidemiologists perceive heat(waves) through raising morbidity and mortality rates. For policymakers, they are an emergency defined by duration and temperature thresholds. Older adults living in Warsaw and Madrid recognize a heat(wave) when they feel it in their bodies, when they cannot sleep, or when they need to change their daily routines. Such differently situated scientific definitions and embodied knowledge stem not only from varied epistemological perspectives but demonstrate that heat(waves) are ontologically different. By looking at convergences and divergences between these perspectives, we see that the length of heat(waves) varies and that older adults often experience longer periods of excessive heat than climate measurements or policy alerts indicate; that the impact of nighttime temperatures is more important than daily temperatures; and that there is a discrepancy between heat(waves) as anomalies and as increasingly common events. The article addresses an important gap between biophysical definitions of heatwaves and the experiences of the most vulnerable groups.

Substandard South Auckland housing: findings from a healthy homes initiative temperature study

ABSTRACT There is strong evidence demonstrating cold housing prevalence in Aotearoa New Zealand. Whānau (families) were recruited from a healthy homes programme based in South Auckland. Forty whānau consented to participate in a temperature-based study that assessed the ability of homes to protect against outdoor temperatures. In this observational study, temperature sensors measured night-time indoor temperature every 15 min from May 2020 to October 2020. Whānau were provided with healthy homes education and practical suggestions to help make homes warmer and dryer. Notably, each device (and house) spent 85% or more of the time below the World Health Organization Housing and Health Guidelines recommended minimum indoor temperature of 20°C for vulnerable groups. The lower standard of 18°C for more general populations referenced in the Healthy Homes Standards was not met over 60% of the time. Over a quarter of the time temperatures measured inside homes were below 12°C. If Māori and Pacific whānau continue to live in substandard housing due to residential inequities, they will continue to experience inequitable health outcomes related to cold housing. Solutions include the anticipated Residential Tenancies (Healthy Homes Standards) Regulations, supports for tenants and support with housing-related costs.

Controlling growth and carbohydrate utilization of tomato seedlings through day-night temperature difference and high light intensity under elevated CO2 conditions

Negative DIF, increasing nighttime temperature relative to daytime temperature, is widely used in the floral industry to reduce plant height. However, negative DIF can also reduce photosynthetic capacity in vegetative seedlings. We investigated the use of negative DIF combined with high light intensity under elevated CO2 and a long photoperiod to produce compact and well-developed tomato seedlings with reduced plant height. Seedlings were grown for 28 days under positive or negative DIF (with daytime/nighttime temperatures of 25 °C/19 °C or 21 °C/27 °C, respectively) combined with low or high light intensity [250 or 500 μmol m−2 s−1 photosynthetic photon flux density (PPFD), PPFD 250 or PPFD 500, respectively] at 1000 ppm CO2 (mean daily temperature: 23 °C across a photoperiod of 16 h d−1). Compared with positive DIF and PPFD 250, negative DIF with PPFD 500 significantly reduced plant height while tending to increase dry matter (DM) but decrease leaf area (LA). Relative growth rate was decreased under negative DIF despite the provision of PPFD 500, but there were no differences in photosynthetic rate and capacity parameters (e.g., total nitrogen and chlorophyll content at the LA level) between DIF treatments. Negative DIF and PPFD 500 might reduce DM by decreasing the amount of intercepted light in tomato seedlings. Negative DIF and PPFD 500 also increased respiration rate during nighttime and led to the consumption of more nonstructural carbohydrates (NSCs) at the LA level. Overall, our results indicate that negative DIF combined with high light intensity can maintain DM, photosynthetic capacity, and plant development while reducing plant height in tomato seedlings.

Puccinia Spore Concentrations in Relation to Weather Factors and Phenological Development of a Wheat Crop in Northwestern Spain

Rust is one of the main diseases affecting wheat crops in Spain, causing significant yield and quality losses. Research on its identification and quantification in the air is a worldwide priority due to the importance of this crop as a source of food and feed. The objective of this study is to determine the temporal variation of airborne spores of Puccinia and their relationship with meteorological variables and the phenological development of a wheat crop in Northwestern Spain during two growing seasons. The study was conducted in A Limia, Ourense, located in Northwestern Spain, during the wheat growing seasons of 2021 and 2022. The Lanzoni VPPS 2010 spore trap was used to collect airborne spores, which were identified using optical microscopy. The wheat growing season was less than 95 days during both years, and wheat rust spores were detected during all phenological stages of the crop. Concentrations were higher than 100 spores/m3 from the booting stage to senescence, mainly in 2021. Statistical analyses showed that temperature was the meteorological variable that most influenced Puccinia concentrations in the air in both years. The modification of a prediction model proposed by other authors for wheat rust, which takes into account mean temperature (10–25 °C), dew point temperature (<5 °C), and nighttime temperature (10–20 °C), allowed us to tentatively predict the increase in Puccinia concentrations in the year 2022 when these conditions occurred for four or five consecutive days. This research is the first in Spain to report the presence of rust-causing Puccinia spores in the air during all phenological stages of the wheat crop and provides useful information for designing management strategies, considering temperature values.

Crowdsourcing air temperature data for the evaluation of the urban microscale model PALM—A case study in central Europe

In summertime and during heat events the urban heat island can negatively impact human health in urban areas. In the context of climate change, climate adaptation receives more attention in urban planning. Microscale urban climate modelling can identify risk areas and evaluate adaptation strategies. Concurrently, evaluating the model results with observational data is essential. So far, model evaluation is mostly limited to short-term field campaigns or a small number of stations. This study uses novel crowdsourcing data from Netatmo citizen weather stations (CWS) to evaluate the urban microscale model PALM for a hot day (Tmax ≥ 30°C) in Bochum in western Germany with anticyclonic atmospheric conditions. Urban-rural air temperature differences are represented by the model. A quality control procedure is applied to the crowdsourced data prior to evaluation. The comparison between the model and the crowdsourced air temperature data reveals a good model performance with a high coefficient of determination (R2) of 0.86 to 0.88 and a root mean squared error (RMSE) around 2 K. Model accuracy shows a temporal pattern and night-time air temperatures during the night are underestimated by the model, likely due to unresolved cloud cover. The crowdsourced air temperature data proved valuable for model evaluation due to the high number of stations within urban areas. Nevertheless, weaknesses related to data quality such as radiation errors must be considered during model evaluation and only the information derived from multiple stations is suitable for model evaluation. The procedure presented here can easily be transferred to planning processes as the model and the crowdsourced air temperature data are freely available. This can contribute to making informed decisions for climate adaptation in urban areas.

Critical evaluation of the agro-ecological system of the Republic of South Africa (30°S) in response to unclassified claims of cocoa farming beyond 20°S of the equator.

Cocoa is a climate sensitive species that has never been reported to grow or survive outside its natural climate belt (20°N-20°S of the equator). Recent reports claimed that cocoa is currently cultivated in Eswatini (26°S), Botswana (22°S), Namibia (22°S), Lesotho (29°S), and the Republic of South Africa "RSA" (30°S). How true are these reports? Climatological and epidemiological investigations were setup to debunk or support these claims. The clime of RSA was investigated since it was the farthest from the cocoa production clime. A review of the climate data of RSA showed 12.4 and 6.1% increase in night-time and day-time temperatures, respectively i.e., from 9.7 and 24.4°C (1901-1930) to 10.9 and 25.9°C (1991-2020), affirming the influence of global warming. The consistent increase in the moving average from 1901-2021 with a fluctuation in the seasonal variation, validates this research. A global connection was established between climate suitability for cocoa production and cocoa disease/pathogen establishment (r = -0.39, P-value = 0.089) at P<0.05. Further analysis showed that the annual temperature (10.8°C≥Temp≥25.8°C), humidity (62%) and sunshine distribution (8.4hours/month) of RSA was suitable for cocoa farming, even though water availability was below the recommended level (rainfall≥463.6mm and rainy_days≤5days/month), farm irrigation systems are currently in use. Other findings showed that KwaZulu-Natal was 100% suitable for cocoa farming, followed by Gauteng, Mpumalanga (86%), Eastern Cape, Limpopo, Northwest (71%), Free State, Northern Cape, and Western Cape (57%). The estimated black pod disease status of KwaZulu-Natal (8.6%) and Eastern Cape (6.6%) affirmed the conduciveness of RSA for cocoa farming.

Pavement Temperature Forecasts Based on Model Output Statistics: Experiments for Highways in Jiangsu, China

Forecasts on transportation meteorology, such as pavement temperature, are becoming increasingly important in the face of global warming and frequent disruptions from extreme weather and climate events. In this study, we propose a pavement temperature forecast model based on stepwise regression—model output statistics (SRMOS) at the short-term timescale, using highways in Jiangsu, China, as examples. Experiments demonstrate that the SRMOS model effectively calibrates against the benchmark of the linear regression model based on surface air temperature (LRT). The SRMOS model shows a reduction in mean absolute errors by 0.7–1.6 °C, with larger magnitudes observed for larger biases in the LRT forecasts. Both forecasts exhibit higher accuracy in predicting minimum nighttime temperatures compared to maximum daytime temperatures. Additionally, it overall shows increasing biases from the north to the south, and the SRMOS superiority is greater over the south with larger initial LRT biases. Predictor importance analysis indicates that temperature, moisture, and larger-scale background are basically the key predictors in the SRMOS model for pavement temperature forecasts, of which the air temperature is the most crucial factor in the model’s construction. Although larger-scale circulation backgrounds are generally characterized by relatively low importance, their significance increases with longer lead times. The presented results demonstrate the considerable skill of the SRMOS model in predicting pavement temperatures, highlighting its potential in disaster prevention for extreme transportation meteorology events.

Night warming from tillering to jointing increases post-anthesis flag leaf photosynthetic capacity and wheat yield

Global warming is asymmetric, with the increase in temperature at night being greater than that during the day. The objectives of this study were to assess the effects of night warming during different growth stages on the wheat grain yield, dry matter accumulation and distribution, photosynthetic characteristics, and enzymes related to sucrose metabolism. For that, field experiments with passive night warming were conducted using local spring type cultivars ‘Yangmai 18′ and ‘Sumai 188′ and semi-winter type cultivars ‘Yannong 19′ and ‘Annong 0711′ in two growing seasons in the Yangtze River Basin of China (average night time temperature increases of 1.45 °C and 1.56 °C for 2019–2020 and 2020–2021, respectively). The cultivars were exposed to night warming between four different growth stages (tillering to jointing [NWT-J], jointing to booting [NWJ-B], and booting to anthesis [NWB-A]) after 50% of plants had attained the treatment-start stage (tillering: Zadoks growth stage 21, main shoot and one tiller; jointing: Zadoks growth stage 31, the 1st node was detectable; booting: Zadoks growth stage 41, flag leaf sheath extension stage; anthesis: Zadoks growth stage 60, the beginning of pollination). Plants grown under ambient conditions were considered as the control (NN). Treatment NWT-J increased dry matter accumulation in flag leaves and spikes at anthesis and maturity, ultimately benefiting the yield, and the increase was higher in the semi-winter type cultivars. NWT-J increased not only the chlorophyll content, photosynthetic traits (net photosynthetic rate, stomatal conductance, and transpiration rate), and the activities of the maximum efficiency of PSII photochemistry under dark-adapted wheat flag leaves at the grain-filling stage (14 days after anthesis) but also the activities of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), fructose-1,6-bisphosphatase (FBPase), and glycolate oxidase (GOX), and thus improved the photosynthetic capacity of wheat flag leaves and facilitating photosynthate accumulation. NWT-J also increased sucrose-phosphate synthase activity in flag leaves at the grain-filling stage, which could improve sucrose content. Collectively, early vegetative night warming (warming during tillering-jointing) improved the photosynthetic capacity of the flag leaves during the grain-filling stage and promoted the post-anthesis accumulation of dry matter and the transfer of dry matter to the grains, which ultimately benefited the yield.

Edge grassland provide a stronger thermal buffer against core grassland in the agro-pastoral ecotone of Inner Mongolia

The impact of land use/cover change on land surface temperature is an important topic in research on biodiversity, environment planning, sustainability. However, such studies are rare in grassland ecosystems. Based on morphological spatial pattern analysis, we analyzed the change in grassland landscape patterns in the agro-pastoral ecotone of Inner Mongolia from 2000 to 2020. We also examined the impact of grassland landscape pattern change on productivity and land surface temperature. We found that the grassland area decreased significantly, with grassland fragmentation increasing during the past 20 years. A series of landscape types showed different area changes: the area of islet and perforation increased, and the area of core, edge, and bridge decreased. Compared with the core grassland, the edge grassland shows higher productivity, which is a positive edge effect. Moreover, the edge grassland has a lower daytime temperature, higher nighttime temperature, and a smaller daily range than that in the core grassland. Our study highlights that the edge grassland has higher productivity and stronger thermal buffering. We suggest that more attention should be paid to the edge areas in grassland management to alleviate the thermal stress caused by human induced climate change.

Exploring the nexus between bedroom design and sleep quality in a warming climate

Bedrooms are important spaces that are often overlooked in the design of residential properties. The interior environment of bedrooms directly affects our sleep quality, which affects the quality of our lives and impacts productivity, health, and wellbeing. Insufficient sleep is a well-known problem in society, having significant negative consequences for health. This is compounded during heatwaves when it can be challenging to get sufficient sleep because of high night-time temperatures, especially in temperate climate zones with no tradition of mechanical cooling. A narrative review was used to explore the inter-relationship between sleep quality, bedroom design, indoor environmental quality (IEQ) and overheating. In addition to highlighting the different focus between health research and built environment research, the outcomes indicate that greater attention needs to be given to bedroom design in domestic properties. The originality of the findings relates to the need for evidence to help inform building designers to mitigate the effects of extreme heat on sleep quality, helping to improve resilience and the health of residents in a warming climate.

Heat-tolerant maize for rainfed hot, dry environments in the lowland tropics: From breeding to improved seed delivery

Climate change-induced heat stress combines two challenges: high day- and nighttime temperatures, and physiological water deficit due to demand-side drought caused by increase in vapor-pressure deficit. It is one of the major factors in low productivity of maize in rainfed stress-prone environments in South Asia, affecting a large population of smallholder farmers who depend on maize for their sustenance and livelihoods. The International Maize and Wheat Improvement Center (CIMMYT) maize program in Asia, in partnership with public-sector maize research institutes and private-sector seed companies in South Asian countries, is implementing an intensive initiative for developing and deploying heat-tolerant maize that combines high yield potential with resilience to heat and drought stresses. With the integration of novel breeding tools and methods, including genomics-assisted breeding, doubled haploidy, field-based precision phenotyping, and trait-based selection, new maize germplasm with increased tolerance to heat stress is being developed for the South Asian tropics. Over a decade of concerted effort has resulted in the successful development and release of 20 high-yielding heat-tolerant maize hybrids in CIMMYT genetic backgrounds. Via public–private partnerships, eight hybrids are presently being deployed on over 50,000 ha in South Asian countries, including Bangladesh, Bhutan, India, Nepal, and Pakistan.

Nighttime ambient temperature and sleep in community-dwelling older adults

This longitudinal study examines the association between bedroom nighttime temperature and sleep quality in a sample of community dwelling older adults. Using wearable sleep monitors and environmental sensors, we assessed sleep duration, efficiency, and restlessness over an extended period within participants' homes while controlling for potential confounders and covariates. Our findings demonstrated that sleep was most efficient and restful when nighttime ambient temperature ranged between 20 and 25 °C, with a clinically relevant 5–10 % drop in sleep efficiency when the temperature increased from 25 °C to 30 °C. The associations were primarily nonlinear, and substantial between-subject variations were observed. These results highlight the potential to enhance sleep quality in older adults by optimizing home thermal environments and emphasize the importance of personalized temperature adjustments based on individual needs and circumstances. Additionally, our study underscores the potential impact of climate change on sleep quality in older adults, particularly those with lower socioeconomic status, and supports increasing their adaptive capacity in the face of a changing climate.

MODIS data assessment of the relationship between vegetation and land surface temperature for central vegetation zone of Adamawa State, Nigeria

Global concern over climate change has necessitated the need for the study of the impact of the ever-increasing land surface temperature on the greenness of land covers. Grassland phenological events are dependent on land surface temperature. This work is aimed at assessing the spatio-temporal trend of the relationship between vegetation cover and the day and night-times land surface temperatures in the Northern Guinea Savanna vegetation zone of Adamawa state, Nigeria. Twenty years (2000 to 2019) data series of Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data (MOD09A1), the day-time land surface temperature data (MOD11A), and the night-time land surface temperature (MYOD11A1) were used to spatially compute the Normalized Difference Vegetation Index (NDVI) and day-time and night-time Land Surface Temperatures (LST) for each of the respective years of the study period. The day- and night-time LST were correlated with the NDVI using simple linear regression analysis. The temporal analysis of the results indicate nonlinear changes in both the NDVI, day-time LST, and night-time LST. The results also indicate a negative correlation between LST and NDVI in both cases. Regression analyses of the day-time LST as a function of NDVI revealed a vegetation cover reduction of 0.0063 per Kelvin change in LST (R2 = 0.3026, p &gt; 0005, RMSE = 8.1042) and a night-time vegetation cover reduction of 0.0103 per Kelvin rise in LST (R2 = 0.3697, p &gt; 0.05, RMSE = 3.7511). The relatively low coefficient of determination and the p values implies a weak relationship between the two variables. The parameters however indicate that the night-time LST is a better predictor of the vegetation greenness of the area. The results revealed that LST is a weak determinant of plant phenological events with respect to the study area.

Night-time warming in the field reduces nocturnal stomatal conductance and grain yield but does not alter daytime physiological responses.

Global nocturnal temperatures are rising more rapidly than daytime temperatures and have a large effect on crop productivity. In particular, stomatal conductance at night (gsn ) is surprisingly poorly understood and has not been investigated despite constituting a significant proportion of overall canopy water loss. Here, we present the results of 3 yr of field data using 12 spring Triticum aestivum genotypes which were grown in NW Mexico and subjected to an artificial increase in night-time temperatures of 2°C. Under nocturnal heating, grain yields decreased (1.9% per 1°C) without significant changes in daytime leaf-level physiological responses. Under warmer nights, there were significant differences in the magnitude and decrease in gsn , values of which were between 9 and 33% of daytime rates while respiration appeared to acclimate to higher temperatures. Decreases in grain yield were genotype-specific; genotypes categorised as heat tolerant demonstrated some of the greatest declines in yield in response to warmer nights. We conclude the essential components of nocturnal heat tolerance in wheat are uncoupled from resilience to daytime temperatures, raising fundamental questions for physiological breeding. Furthermore, this study discusses key physiological traits such as pollen viability, root depth and irrigation type may also play a role in genotype-specific nocturnal heat tolerance.

Rice yield and quality in response to daytime and nighttime temperature increase – A meta-analysis perspective

Increased heat stress during cropping season poses significant challenges to rice production, yet the complex stoichiometry between rice grain yield, quality and high daytime, nighttime temperature remains with gaps in current knowledge. We conducted a meta-analysis using a combined dataset of 1105 experiments for daytime temperature and 841 experiments for nighttime temperature from published literature to investigate the effects of high daytime temperature (HDT) and high nighttime temperatures (HNT) on rice yield and its various components (such as panicle number, spikelet number per panicle, seed set rate, grain weight) and grain quality traits (such as milling yield, chalkiness, amylose and protein contents). We established relationships between rice yield, its components, grain quality and the HDT/HNT, and studied phenotypic plasticity of the traits in response to HDT and HNT. Results showed that HNT had a more detrimental impact on rice yield and quality when compared with the HDT. The optimum daytime and nighttime temperatures for best rice yield were approximately 28 °C and 22 °C, respectively. Grain yield showed a decline by 7% and 6% for each 1 °C increase in HNT and HDT, respectively, when exceeded the optimum temperatures. Seed set rate (i.e., percent fertility) was the most sensitive trait to HDT and HNT and accounted for most of the yield losses. Both the HDT and HNT affected grain quality by increasing chalkiness and decreasing head rice percentage, which may affect marketability of the rice produced. Additionally, HNT was found to significantly impact nutritional quality (e.g., protein content) of rice grains. Our findings fill current knowledge gaps on estimations of rice yield losses and possible economic consequences under high temperatures and suggest that impacts on rice quality should also be considered for selection and breeding of high-temperature tolerant rice varieties in response to HDT and HNT.

Dynamically optimizing stomatal conductance for maximum turgor-driven growth over diel and seasonal cycles.

Stomata have recently been theorized to have evolved strategies that maximize turgor-driven growth over plants' lifetimes, finding support through steady-state solutions in which gas exchange, carbohydrate storage and growth have all reached equilibrium. However, plants do not operate near steady state as plant responses and environmental forcings vary diurnally and seasonally. It remains unclear how gas exchange, carbohydrate storage and growth should be dynamically coordinated for stomata to maximize growth. We simulated the gas exchange, carbohydrate storage and growth that dynamically maximize growth diurnally and annually. Additionally, we test whether the growth-optimization hypothesis explains nocturnal stomatal opening, particularly through diel changes in temperature, carbohydrate storage and demand. Year-long dynamic simulations captured realistic diurnal and seasonal patterns in gas exchange as well as realistic seasonal patterns in carbohydrate storage and growth, improving upon unrealistic carbohydrate responses in steady-state simulations. Diurnal patterns of carbohydrate storage and growth in day-long simulations were hindered by faulty modelling assumptions of cyclic carbohydrate storage over an individual day and synchronization of the expansive and hardening phases of growth, respectively. The growth-optimization hypothesis cannot currently explain nocturnal stomatal opening unless employing corrective 'fitness factors' or reframing the theory in a probabilistic manner, in which stomata adopt an inaccurate statistical 'memory' of night-time temperature. The growth-optimization hypothesis suggests that diurnal and seasonal patterns of stomatal conductance are driven by a dynamic carbon-use strategy that seeks to maintain homeostasis of carbohydrate reserves.

The land-sea breeze influences the oceanography of the southern Benguela upwelling system at multiple time-scales

The physical and biogeochemical functioning of eastern boundary upwelling systems is generally understood within the context of the upwelling - relaxation cycle, driven by sub-diurnal wind variability (i.e. with a time-scale of greater than a day). Here, we employ a realistically configured and validated 3D model of the southern Benguela upwelling system to quantify the impact of super-diurnal winds associated with the land-sea breeze (LSB). The ocean response to the LSB is found to be particularly enhanced within St Helena Bay (SHB), a hotspot for productivity which is also prone to Harmful Algal Bloom (HAB) development. We attribute the enhanced response to a combination of near-critical latitude for diurnal-inertial resonance (~32.5°S), the local enhancement of the LSB, and the local development of a shallow stratified surface layer through bay retention. Pronounced advection of the surface layer by diurnal-inertial oscillations contributes to large differences in day- and night-time sea surface temperatures (SST’s) (more than 2°C on average in SHB). Event-scale diapycnal mixing is particularly enhanced within SHB, as highlighted by a numerical experiment initialised with a subsurface passive tracer. These super-diurnal processes are shown to influence sub-diurnal dynamics within SHB through their modulation of the vertical water column structure. A deeper thermocline retains the upwelling front closer to land during active upwelling, while geostrophically-driven alongshore flow is impacted through the modulation of cross-shore pressure gradients. The results suggest that the LSB is likely to play an important role in the productivity and therefore HAB development within SHB, and highlight potential challenges for observational systems and models aiming to improve our understanding of the physical and biological functioning of the system.

Passive solar tracker using a bimetallic strip activator with an integrated night return mechanism

Passive solar trackers face challenges in returning PV panels to the east position before sunrise. Specifically, bimetallic strip deflection-based trackers are unreliable due to ambient temperature changes at night, resulting in inconsistency across different locations and times. This study addresses this issue by designing a passive solar tracker with a bimetallic strip deflector independent of nighttime temperature differences. Field tests were conducted comparing a fixed system to the proposed tracker. Performance parameters included power output, power density, and energy collection. The proposed tracker achieved a daily average power output of 70–120 W, while the fixed system ranged from 10 to 120 W. The proposed system exhibited steady changes in power output, providing an additional 47 W per unit area compared to the fixed system. This optimization maximized power output within a given area, resulting in a cost savings of $71.75 per unit area. The proposed system also demonstrated 24.86% higher energy collection efficiency relative to the fixed system and 96.4% accuracy compared to an ideal tracking system. It is a cost-effective alternative to fixed-panel PV and easy to install and operate. Additionally, it can be used in conjunction with active tracking systems, offering comparable efficiency at a lower operational cost. The designed system presents a reliable solution by being independent of nighttime temperature fluctuations, making it more stable relative to other passive solar trackers.

Mejora del desempeño térmico de colegios en la Región Altoandina del Perú. El caso del “módulo prefabricado aula tipo heladas - PRONIED”

Faced with the qualitative and quantitative deficit of educational infrastructure in Peru’s rural high Andean areas, in recent years the Peruvian State has been investing in and supporting modular solutions, seeking efficiency in the construction processes. The specific proposal, with special emphasis on bioclimatic design, is the "Prefabricated Frost-type Modular Classroom". However, users have been expressing discomfort with these new facilities. This study shows the measurement process carried out on a built module, which allowed calibrating and validating the model using simulation software, to propose improvements in the design that may contribute to future constructions. Taking the adaptive thermal comfort model as a reference, it was confirmed that indoor temperatures were below thermal comfort limits in the early hours of the morning and well above them close to noon, by around 6 ºC and 7 ºC respectively. With the application of complementary bioclimatic strategies, it was possible to considerably improve indoor thermal conditions, although not enough to reach comfort early in the morning. This is because the night-time outdoor temperatures are very low, the building is uninhabited all night long, there is no thermal mass in the envelope, and there are no active solar systems or mechanical air conditioning.