Monthly Mean Relative Humidity Research Articles

Carbonation depth model for loaded reinforced concrete (RC) beams under time-dependent relative humidity conditions

Steel bar corrosion caused by concrete carbonation is one of the important factors of the durability failure of reinforced concrete (RC) structures. The annual relative humidity (RH) in the upper reaches of the Yangtze River shows obvious time-dependent characteristics. The important wharf components represented by RC beams bear flexural loads during their long-term service. The carbonation of RC structures under the coupling of the service environment and flexural load is very complicated. However, corresponding studies on the carbonation of loaded RC structures are mostly carried out in a constant RH environment, which is quite different from the time-dependent RH (T-RH) conditions in the upper reaches of the Yangtze River. For this study, the RC beam of a wharf in the upper reaches of the Yangtze River is treated as the research object. According to the long-term observation data of the 24-year daily mean RH at this wharf site, the periodic (time-dependent) characteristics of RH in a typical year are obtained by statistical analysis. On this basis, a physical experiment for RC beam specimens subjected to flexural loads under an accelerated carbonation environment with T-RH is carried out to explore the influence of the coupling effect of the T-RH and flexural load on the concrete carbonation behaviour. The results showed that the range of RH is basically distributed from 45 to 95%, and the monthly mean RH over a typical year shows a 'W'-shaped periodic characteristic. The compressive strength and concrete carbonation depth under the T-RH environment are larger than those under the C-RH carbonation environment; hence, the carbonation degree of concrete under a T-RH environment is more serious. When the flexural load level is less than 1.0, the flexural tensile stress can accelerate the carbonation degree of RC specimens, and the carbonation depth of concrete is positively correlated with the flexural load level. When the flexural load does not reach the concrete compressive strength, the flexural compressive stress can inhibit concrete carbonation. Based on the experimental measurements, the carbonation depth model for loaded RC beams under the T-RH is established, and the accuracy of the model is verified by the original test data collected during 27 years of the natural carbonation of RC beams. Through the studies and achievements presented in this paper, the carbonation trends of loaded RC beams under T-RH are revealed, and the corresponding mathematical model is established, which can be used to evaluate the carbonation depth of loaded RC beams considering T-RH in general atmospheric environments. The research results can provide a basis for RC structure durability evaluation in the upper reaches of the Yangtze River and have important guiding significance for practical engineering.

Effects of Future Climate Change on Citrus Quality and Yield in China

As the world’s most widely cultivated fruit, citrus in China is increasingly suffering from ongoing climate change, which affects the sustainability of agricultural systems and social economy. In this study, we linked climate factors to citrus quality and yield and established projection models to elucidate the impact of future climate change. Then, we used the ensemble mean of 19 Coupled Model Intercomparison Project 6 (CMIP6) models to project the 2021–2040 and 2041–2060 climate changes relative to the historical baseline 1995–2014 period under different shared socioeconomic pathways scenarios (SSP2-4.5, SSP5-8.5). The results show that the monthly mean diurnal temperature range in July had the greatest influence on quality, and monthly mean temperature in October, monthly mean relative humidity in October, monthly mean minimum temperature in November and monthly mean maximum temperature in September had the greatest influence on yield at the growth and ripening stages. Moreover, the quality and yield of citrus present different characteristics in terms of change in cultivation areas in the future. The quality of Sichuan, Zhejiang and Fujian Provinces in China will become significantly better, however, Hubei, Guangdong and Guangxi Provinces it will become worse. Surprisingly, yield will increase in all plantations due to future suitable climate conditions for citrus growth and ripening.

Assessing seasonal climate variability impact on the malaria patient’s cases in the north of Côte d'Ivoire

In recent years, the impact of climate change on human health has attracted considerable attention including their effects on malaria, which have been of particular interest due to its disease burden and transmission sensitivity to climatic conditions. The main objective of the study is to examine the relationship between intra-annual climate variability and malaria transmission in the north of Côte d’Ivoire. The monthly incidence of malaria in Korhogo 1 health district was treated as a dependent variable, and meteorological variables were independent variables. Our results highlighted that malaria is influenced by all three climatic variables (rainfall, temperature and relative humidity). The highest effect of temperature, relative humidity, and rainfall on malaria cases is observed in the months of June, July, August, September, October and November respectively. The monthly rainfall and the monthly mean relative humidity were highly correlated to monthly incidence of malaria in population under-five years old. Meanwhile, the monthly mean temperature was highly correlated to malaria incidence of pregnant women over 15 years old and to monthly incidence of malaria in under-five. Moreover, combining monthly rainfall and monthly mean temperature, monthly rainfall and monthly mean relative humidity and monthly mean temperature and relative humidity were highly correlated to malaria incidence in patients influenced by the rainy season exclusively. The combination between monthly rainfall and monthly mean relative humidity was closely correlated to malaria incidence in malaria patient influencedby rainy and/or dry season.

Differences of drought tolerance of the main tree species in Dongling Mountain, Beijing, China as indicated by tree rings

Forests in Beijing exhibit vulnerability to increasing stress of extreme drought in recent years. To investigate the drought tolerance of different tree species, we chose three tree species (Larix principis-rupprechtii, Pinus tabuliformis, and Quercus wutaishanica) from the forest of Dongling Mountain in Beijing and used dendroecological method to analyze the relationship between radial growth and climate, as well as their resistance and resilience to extreme drought events. Our results showed that the radial growth of L. principis-rupprechtii and P. tabuliformis was significantly negatively correlated with monthly mean temperature from May to June, but that of Q. wutaishanica was significantly negatively correlated with monthly mean temperature only in May. The radial growth of L. principis-rupprechtii was significantly positively correlated with monthly mean precipitation in June, monthly mean relative humidity from May to June and August to September. The radial growth of P. tabuliformis was significantly positively correlated with monthly mean precipitation and monthly mean relative humidity from June to August. The radial growth of Q. wutaishanica was significantly positively correlated with monthly mean precipitation in February and May, and monthly mean relative humidity in May. The radial growth of all the three species was significantly positively correlated with monthly mean SPEI (standardized precipitation evapotranspiration index) from May to July. L. principis-rupprechtii was least drought tolerant, as indicated by the greatest growth reduction (46.6%-69.6%), lowest resistance (0.534, 0.304, 0.530) and resilience (0.686, 0.570, 0.753) during the three extreme drought events occurred in the 1994, 2001-2002, and 2007. In contrast, tree growth of Q. wutaishanica showed the highest drought resistance in 2007, whereas no significant differences were observed between other two species. Extreme drought events caused by continuous high temperature and reduced precipitation during the growing season accounted for the reduction in tree radial growth. The various physiological and ecological strategies of tree species were the possible reasons for the difference in drought tolerance. Our results could provide a basis for the selection of suitable afforestation tree species and the formulation of forest protection mea-sures to maintain forest ecosystem functions and services under the background of undergoing climate change.

Species diversity and molecular insights into phlebotomine sand flies in Sardinia (Italy)-an endemic region for leishmaniasis.

This study provides updated information on the distribution of the phlebotomine sand fly species and their genetic characterization in Sardinia, a Mediterranean island where leishmaniasis is endemic. From April to November 2017, sand flies were trapped in five different capture sites using sticky traps and light traps as collection methods, operated nearby sheep, poultry, cat, and dog shelters. Phlebotomine specimens (n = 513) collected were morphologically and molecularly identified as Phlebotomus perniciosus (249/513, 48.5%), Phlebotomus perfiliewi (236/513; 46%), and Sergentomyia minuta (28/513, 5.5%). Sand flies were collected from the second half of May to October confirming the well-defined seasonal activity, which peaks in August in Sardinia. Overall, correlation analyses indicated a significant positive association between the monthly number of sand flies collected and the mean temperature (r = 0.88, rho = 0.87, and tau = 0.69, P < 0.05), while there was non-significant, moderately negative correlation between the monthly number of sand flies collected and the monthly mean relative humidity and wind (r = - 0.22, rho = 0.02, and tau = 0.04, P > 0.05). This study provides the first data on the molecular characterization of phlebotomine sand flies in this region and confirms the presence of three sand fly species. Molecular results suggest that the morphological features used for analysis represent synapomorphic-derived characters which are shared among descendant taxa and the common ancestor.

Population fluctuation of Culicoides insignis Lutz (Diptera: Ceratopogonidae) in Posadas, Misiones, Argentina

The Bluetongue virus appears to be restricted in Argentina to the northeastern area of the country. In the Neotropical region the main vector could be Culicoides insignis Lutz. This study was aimed to determine the population fluctuation of C. insignis in Posadas city and test the influence of climatic variables as determinants of the abundance of this species. The specimens were collected in Posadas city using CDC light traps from January to December 2013. The abundance of C. insignis in relation to environmental variables was analyzed using multivariate linear regression. A total of 2,952 specimens of C. insignis were collected representing 93.4% of the total Culicoides captured. The multivariate linear regression analyses show that the monthly mean relative humidity was the variable that best explained the population dynamics of C. insignis in the work area. The pathogen transmission is probably influenced by the abundance of the vector in this area. The population peaks observed are indicative of periods when there should be more control to prevent transmission of the disease. This is the first report of population fluctuation of C. insignis in northeastern Argentina

Influence of atmospheric states in semi-arid areas on hospital admission in cardio-surgical department.

The influence of the changes in atmospheric state, typical for areas close to big deserts, on acute myocardial infarction (AMI) was analyzed. Under test was the group of 3256 patients (77% males, 23% females), hospitalized in the Cardio-Surgical Department of Soroka Medical Center at Ben-Gurion University (BGU, Israel) during 2000-2008. To explore the relationship between atmospheric parameters and AMI, multivariate regression analysis has been performed. AMI was most frequent in winter to spring and least in summer. The highest number of cases was recorded in December and the lowest in September. Hospital admissions showed a higher prevalence in men than in women; the ratio is 3.3/1.0. About 60% of males were aged between 45 and 65years old with maximum ∼55 (21%), whereas 60% of women hospital admissions were aged between 65 and 80years old with maximum ∼72 (24%). The result suggested that the monthly mean relative humidity at daytime and its overall daily differences, wind speed, and respirable fraction of particulate concentration are associated with the admission for AMI. The results of the study confirm the importance of atmospheric state variability for cardiovascular diseases.

Population dynamics of ticks infesting the one-humped camel (Camelus dromedarius) in central Tunisia

A tick population was monitored on 30 camels (Camelus dromedarius) over one year in Kairouan region, Central Tunisia. A total of 1630 ticks was collected and identified resulting in an estimate of different parasitological indicators. The ticks belonged to 2 genera and 5 species: Hyalomma impeltatum (53%) and Hyalomma dromedarii (45%) were the dominant species followed by Hyalomma excavatum (1%), Hyalomma marginatum (0.5%), and Rhipicephalus turanicus (0.5%) (p<0.001).Mean infestation prevalence was 90.6%; all the animals were infested by at least one tick from May to September. The highest mean prevalence was observed in H. impeltatum (60%), the lowest was reported in R. turanicus (0.03%) (p<0.05). Mean overall intensity of infestation was 4.4 ticks/animal. The highest mean intensity was observed in H. impeltatum (2.7 ticks/animal). Overall mean abundance of ticks was 4.4 ticks/animal. Different abiotic factors, namely monthly mean minimum and monthly mean maximum temperatures and the number of sunny days were positively correlated with overall monthly tick burdens which were in turn negatively correlated with the monthly mean relative humidity. This is the first study on camel tick dynamics in Tunisia.

Estimation of relative humidity based on artificial neural network approach in the Aegean Region of Turkey

The aim of this study is to estimate the monthly mean relative humidity (MRH) values in the Aegean Region of Turkey with the help of the topographical and meteorological parameters based on artificial neural network (ANN) approach. The monthly MRH values were calculated from the measurement in the meteorological observing stations established in Izmir, Mugla, Aydin, Denizli, Usak, Manisa, Kutahya and Afyonkarahisar provinces between 2000 and 2006. Latitude, longitude, altitude, precipitation and months of the year were used in the input layer of the ANN network, while the MRH was used in output layer of the network. The ANN model was developed using MATLAB software, and then actual values were compared with those obtained by ANN and multi-linear regression methods. It seemed that the obtained values were in the acceptable error limits. It is concluded that the determination of relative humidity values is possible at any target point of the region where the measurement cannot be performed.

A numerical study of the influence of urban expansion on monthly climate in dry autumn over the Pearl River Delta, China

In this study, we employed a regional model to simulate the impact of urban expansion on monthly climate in Pearl River Delta (PRD) region. Two experiments were performed by prescribing two different land covers in the PRD region. One land cover represents vegetation in the 1970s which is derived from the United States Geological Survey (USGS) data with 24-category (hereafter referred to as NU). The other land cover represents the current urban condition which is derived from remote sensing data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) in 2004 (hereafter referred to as HU). Using the two land cover datasets, monthly climate of October 2004 was simulated, which was a very dry season in the PRD region. The results obtained from the numerical simulation show a distinct difference in simulated shelter-level temperature, humidity, surface fluxes and the height of planetary boundary layer (PBL) with two different land cover data sets being specified. The maximum difference in simulated monthly mean temperature over urban areas was 0.9 °C. A large temperature difference was found in urbanized area in Guangzhou, Dongguan, Zhongshan and Shenzhen. The monthly mean relative humidity in urban areas decreased by 1.4% as a result of urban expansion (from 59.2% in NU to 57.8% in HU). The maximum decrease in mixing ratio was 0.4 g/kg in Guangzhou and Dongguan, whereas the maximum decrease in relative humidity was 2.4%. There was an increase of sensible heat flux in developed lands and the maximum increase was 90 W m−2. In contrast, latent hear flux in urban area decreased and the maximum decrease was 300 W m−2. In addition, the increase in mean height of PBL ranged from 20 to 80 m (HU compared with NU), and the maximum change of the height was 180 m over urban area in city of Guangzhou.

Variation in Weight of Milled Raw Rice During Storage

A study on storage of rice was conducted to find the effect of moisture content on the weight of milled raw rice for a period of one-year under stacking condition and the correlation between loss or gain in weight of rice on moisture content basis and actual weighment basis was determined. During the period from March to May and September to November there were continuous losses in the weight of rice whereas in the months of January- February and the period from June to August there was continuous gain in weight. The results indicated a positive correlation (0.88) between the losses based on moisture content and actual weighment. It was also found that 89% of the total variation in the loss or gain in the weight of rice (PR-114) could be accounted for by a linear function involving the monthly mean relative humidity of the store room in addition to the difference in moisture content.

Climatic variables and transmission of malaria: a 12-year data analysis in Shuchen County, China.

The objective of this study was to explore the impact of climate variability on the transmission of malaria, a vector-borne disease, in a county of China and provide suggestions to similar regions for disease prevention. A time-series analysis was conducted using data on monthly climatic variables and monthly incidence of malaria in Shuchen County, China, for the period 1980-1991. Spearman's correlation analysis showed that monthly mean maximum and minimum temperatures, two measures of monthly mean relative humidity, and monthly amount of precipitation were positively correlated with the monthly incidence of malaria in the county. Regression analysis suggested that monthly mean minimum temperature and total monthly rainfall, with a one-month lagged effect, were significant climatic variables in the transmission of malaria in Shuchen County. Seasonality was also significant in the regression model and there was a declining secular trend in the incidence of malaria. The results indicate that climatic variables should be considered as possible predictors for regions with similar geographic, climatic, and socioeconomic conditions to those of Shuchen County.

Climatic variables and transmission of malaria: a 12-Year data analysis in Shuchen County, China

Objective. The objective of this study was to explore the impact of climate variability on the transmission of malaria, a vector-borne disease, in a county of China and provide suggestions to similar regions for disease prevention. Methods. A time-series analysis was conducted using data on monthly climatic variables and monthly incidence of malaria in Shuchen County, China, for the period 1980-1991. Results. Spearman's correlation analysis showed that monthly mean maximum and minimum temperatures, two measures of monthly mean relative humidity, and monthly amount of precipitation were positively correlated with the monthly incidence of malaria in the county. Regression analysis suggested that monthly mean minimum temperature and total monthly rainfall, with a one-month lagged effect, were significant climatic variables in the transmission of malaria in Shuchen County. Seaonality was also significant in the regression model and there was a declining secular trend in the incidence of malaria. Conclusion. The results indicate that climatic variables should be considered as possible predictors for regions with similar geographic, climatic, and socioeconomic conditions to those of Shuchen County.