Pre-rainy Season Research Articles

Spatiotemporal variability of lake surface water temperature and water quality parameters and its interrelationship with water hyacinth biomass in Lake Tana, Ethiopia.

Urbanization, agriculture, and climate change affect water quality and water hyacinth growth in lakes. This study examines the spatiotemporal variability of lake surface water temperature, turbidity, and chlorophyll-a (Chl-a) and their association with water hyacinth biomass in Lake Tana. MODIS Land/ Lake surface water temperature (LSWT), Sentinel 2 MSI Imagery, and in-situ water quality data were used. Validation results revealed strong positive correlations between MODIS LSWT and on-site measured water temperature (R = 0.90), in-situ turbidity and normalized difference turbidity index (NDTI) (R = 0.92), and in-situ Chl-a and normalized difference chlorophyll index (NDCI) (R = 0.84). LSWT trends varied across the lake, with increasing trends in the northeastern, northwestern, and southwestern regions and decreasing trends in the western, southern, and central areas (2001-2022). The spatial average LSWT trend decreased significantly in pre-rainy (0.01 ℃/year), rainy (0.02 ℃/year), and post-rainy seasons (0.01℃/year) but increased non-significantly in the dry season (0.00 ℃/year) (2001-2022, P < 0.05). Spatial average turbidity decreased significantly in all seasons, except in the pre-rainy season (2016-2022). Likewise, spatial average Chl-a decreased significantly in pre-rainy and rainy seasons, whereas it showed a non-significant increasing trend in the dry and post-rainy seasons (2016-2022). Water hyacinth biomass was positively correlated with LSWT (R = 0.18) but negatively with turbidity (R = -0.33) and Chl-a (R = -0.35). High spatiotemporal variability was observed in LSWT, turbidity, and Chl-a, along with overall decreasing trends. The findings suggest integrated management strategies to balance water hyacinth eradication and its role in water purification. The results will be vital in decision support systems and preparing strategic plans for sustainable water resource management, environmental protection, and pollution prevention.

Physical and chemical features of hydro-geologically connected wetlands in the Abbay River basin, Ethiopia

Physico-chemical water quality assessment is vital for wetland characterization, detecting environmental stress affecting the ecosystem and wetland management interventions. Therefore, this study aimed at comprehensive analysis of water quality parameters of six hydro-geologically connected wetlands in West Gojjam zone, Amhara region, Ethiopia. Water quality data was collected for one year (from June 2022 to April 2023) during four sampling seasons (pre-rainy, main-rainy, post-rainy and dry seasons) from twelve purposively selected sampling sites. In-situ measurements and nutrient analysis were carried out following standard procedures. Water quality index (WQI) was also computed by the weighted arithmetic water quality index method (WAWQI) based on selected parameters. Phosphate ranged from 0.24 mg/l (Kurt Bahir) to 1.80 mg/l (Zindib) and nitrate ranged from 2.12 mg/l (at Gudera) to 3.25 mg/l (at Geray). This increased nutrient concentration and the decreasing trend in DO level clearly indicates their ecological degradation. There was a statistically significant difference (P < 0.05, One-way ANOVA) in the mean measurements of some of the parameters among the study wetlands and among the study seasons. The PCA also clearly shows the most influential variables responsible for the variation among the wetlands. The study concluded that the wetlands water quality has been degraded. Therefore, regular water quality monitoring is recommended to reduce further deterioration.

Interpretable convolutional neural network for analyzing precipitation in the pre-rainy season of South China

Abstract The research and application of convolutional neural networks (CNNs) on statistical downscaling have been hampered by the fact that deep learning is highly dependent on sample size and is considered to be a black-box model. Therefore, a CNN model with transfer learning (CNN-TL) is proposed to study the pre-rainy season precipitation of South China. First, an augmented monthly dataset is created by sliding a fixed-length window over the daily circulation field and precipitation data for the entire year. Next, a base CNN network is pretrained on the augmented dataset, and then the network parameters are tuned on the actual monthly dataset from South China. Finally, guided backpropagation is conducted to obtain the distribution regions of the key features and explain the net. The coefficient of determination (R2) and root mean square error (RMSE) show that the CNN-TL model has higher explanatory power and better fitting performance than the feature extraction-based random forest (RF). Compared with the base CNN, the transfer learning approach can improve the explanatory power of the model by 10.29% and reduce the average RMSE by 6.82%. In addition, the interpretation results of the model show that the critical regions are primarily South China and its surrounding areas, including the Indochinese Peninsula, the Bay of Bengal, and the South China Sea. Furthermore, the ablation experiments and composite analysis illustrate that these regions are very important.

High prevalence of Zika virus infection in populations of Aedes aegypti from South-western Ecuador.

We performed an arboviral survey in mosquitoes from four endemic Ecuadorian cities (Huaquillas, Machala, Portovelo and Zaruma) during the epidemic period 2016-2018. Collections were performed during the pre-rainy season (2016), peak transmission season (2017) and post-rainy season (2018). Ae. aegypti mosquitoes were pooled by date, location and sex. Pools were screened by RT-PCR for the presence of ZIKV RNA, and infection rates (IRs) per 1,000 specimens were calculated. A total of 2,592 pools (comprising 6,197 mosquitoes) were screened. Our results reveal high IRs in all cities and periods sampled. Overall IRs among female mosquitoes were highest in Machala (89.2), followed by Portovelo (66.4), Zaruma (47.4) and Huaquillas (41.9). Among male mosquitoes, overall IRs were highest in Machala (35.6), followed by Portovelo (33.1), Huaquillas (31.9) and Zaruma (27.9), suggesting that alternative transmission routes (vertical/venereal) can play important roles for ZIKV maintenance in the vector population of these areas. Additionally, we propose that the stabilization of ZIKV vertical transmission in the vector population could help explain the presence of high IRs in field-caught mosquitoes during inter-epidemic periods.

Potentiality of Sustainable Maize Production under Rainfed Conditions in the Tropics by Triggering Agro-Physio-Biochemical Traits Ascertained from a Greenhouse.

A major portion of maize is produced under rainfed conditions in the tropics with relatively poor yield because of the unpredictable and irregular distribution of seasonal rainfall, as well as a decline in pre-rainy season rainfall due to climate change, so identification of sustainable production options is utmost needed. Thus, the present studies were conducted in a greenhouse (GH) to ascertain the water stress-tolerant traits of maize and at the field level in the tropical environment of Thailand to see the stimulating possibility of the ascertained traits in a locally popular cultivar using ethephon. Depending on tolerance level, three maize genotypes (Suwan 2301 > Suwan 4452 > S 7328) were tested under different water conditions-well-watered, short-term, and long-term water stress-in the GH. At the field level, the locally popular maize cultivar Suwan 5819 was examined with six ethephon levels (doses in g a.i. ha-1 of ethephon, i.e., T1, 281 at V6 stage; T2, 281 at V6 + 281 at V10 stage; T3, 281 at V10 stage; T4, 562 at V6 stage; T5, 562 at V6 + 562 at V10 stage; T6, 562 at V10 stage) against no ethephon application (T0) under rainfed conditions. Maize suffered from the scarcity of sufficient rainfall during 26-39 days after planting (DAP) and 43-63 DAP in the field. The yield index (YI) was identified from biplot analysis as one of the suitable standards for drought tolerance checks for maize at GH as well as at field level in the tropics. The YI value of observed agro-physio-biochemical traits of maize in GH showed that relative water content (RWC, 1.23), stem base diameter (SBD, 1.21), total soluble sugar (TSS, 1.15), proline (Pr, 1.13), aboveground plant biomass (APB, 1.13), root weight (RW, 1.13), relative growth rate (RGR, 1.15), specific leaf weight (SLW, 1.12), and net assimilation rate (NAR, 1.08) were the most desirable. Efforts were made to stimulate these traits under water stress at the field level. Ethephon application as T1 helped to gain higher kernel yield (KY) (5.26 t ha-1) with the support of higher RWC (90.38%), proline (24.79 µmol g-1 FW), TSS (1629 mg g-1 FW), SBD (24.49 mm), APB (271.34 g plant-1), SLW (51.71 g m-2), RGR (25.26 mg plant-1 day-1), and NAR (0.91 mg cm-2 day-1) compared to others, especially no ethephon application. Furthermore, the attributes SLW, SBD, Pr, heat utilization efficiency (HUE), 100-kernel weight, TSS, electrolyte leakage, and lodging percentage showed a substantial direct effect and significant correlation with KY. Aside from higher KY, ethephon application as T1 tactics resulted in higher values of energy efficiency (1.66), HUE (2.99 kg ha-1 °C days-1), gross margin (682.02 USD ha-1), MBCR (3.32), and C absorption (6.19 t C ha-1), indicating that this practice may be a good option for maize sustainable production under rainfed conditions.

Estimation of Water Spread Area in Selected Tanks of Cuddalore District of Tamil Nadu Using Sentinel-1A SAR Data

The most important aspect of water resource planning and management is mapping and regular monitoring of surface water bodies. Remote sensing has become most widely used method for measuring and monitoring of water body dynamics due its temporal and spatial availability of high-resolution data. A study was conducted to map and estimate the water spread area in the tanks of Kattumannarkoil block of Cuddalore district of Tamil Nadu using Sentinel-1A SAR satellite data. European Space Agency’s Sentinel-1A data provides high quality SAR data which is used widely for monitoring of crop and water resources. The acquisition and preprocessing of satellite data was done using Google Earth Engine. The obtained satellite image from Google Engine was processed using ArcGIS. The water spread area was derived from the processed data using thresholding approach. The back-scattering values generated through pre-processing ranges from -18.00 db to -28.12 db for August 2022 (Pre-rainy season), -15.85 to -26.96 for December 2022 (Post-rainy season) and -15.55 to -24.82 for April 2023(Summer time). The estimated water spread area in selected 12 Tanks were 37.191 ha, 58.34 ha and 59.971 ha on 19th August 2022, 17th December 2022 and 16th April 2023 respectively.

The use of camera traps to study the hooded skunk &lt;i&gt;Mephitis macroura&lt;/i&gt; (Carnivora: Mephitidae) abundance

Skunks are important for the ecosystems as consumers of fruits, seeds, and insects. The hooded skunk (Mephitis macroura) is a medium-sized mammal common in North America, but its abundance is poorly known throughout its range. In a semiarid location in southern Mexico, we deployed a camera traps array to study the populations of meso-carnivores in three seasons. With 2520 camera days of sampling effort, we obtained 41 photographs of the hooded skunk, an average of 6.2 photographs per station, meaning a capture rate of 1.63 photographs/camera day per 100. Based on pelage color patterns and specific characteristics, we identified 25 individuals (seven to twelve skunks per season). Single camera-trap stations recorded up to seven different skunk individuals (an average of 3.6 individuals). The maximum number of capture-recaptures was four for three skunk individuals, and the average capture-recapture record was 1.4 per skunk. Although the survey area was appropriate for mesocarnivores, no spatial recaptures were observed for hooded skunks because the distance between cameras was longer. Traditional capture-recapture models estimated hooded skunk abundance at 12.60, 21.10, and 20.20 skunks during the dry, pre-rainy, and rainy seasons, respectively. The capture rate was higher than reported in other camera trapping surveys in Mexico, and estimated abundances were the lowest but, in the range, reported for the species using other techniques. Idiosyncratic characteristics of hooded skunks are useful to the recognition of individuals, but we recommend testing short distances among cameras to achieve spatial recaptures and to apply contemporary spatial capture-recapture analyses.

Productivity and profitability of maize (Zea mays) cultivars under organic management condition in mid-hills of Sikkim

A field experiment was conducted during pre-rainy (kharif) seasons of 2019 and 2020 at Research Farm of ICAR Research Complex for North Eastern Hill Region, Sikkim Centre, Tadong, Gangtok, Sikkim to evaluate the performance of maize (Zea mays L.) cultivars under organic management condition. Twelve cultivars of maize, viz. ‘Seti Makkai’, ‘Pahenlo Makkai’, ‘Rato Makkai’, ‘Baiguni Makkai’, ‘Kalo Makkai’, ‘Satheya’, ‘RCM 1–1’, ‘RCM 1–3’, ‘RCM–75’ and ‘Vivek Sankul 31’, ‘Vivek Sankul 37’ and ‘Vivek Sankul 35’ were evaluated under organic management system in randomized complete block design. The results showed that cultivar ‘Seti Makkai’ recorded significantly maximum plant height (305 cm) as compared to the other cultivars. The highest dry-matter accumulation (81 g/plant) was registered under ‘Rato Makkai’ which was significantly superior to that of remaining cultivars. The maximum leaf-area index was recorded under ‘Vivek Sankul 35’ (4.35) as compared to the other cultivars. The minimum days required to 50% flowering (61 days) was noticed under ‘Vivek Sankul 35’. As compared to the other cultivars, the maximum cob length (16.7 cm) was recorded under ‘RCM 1-1’. ‘Vivek Sankul 31’ registered significantly higher cob girth (13.4 cm) than the others. Number of rows/cob (12.9) was significantly higher in ‘Vivek Sankul 35’ than the remaining cultivars. Maximum number of grains/row was registered in ‘Kalo Makkai’ (36.8). The highest grain yield (3.97 t/ha) and economic benefits were recorded with ‘Vivek Sankul 35’ as compared to the remaining cultivars. Short- duration maize cultivar ‘Vivek Sankul 35’ was found most promising in terms of productivity and profitability and may be recommended for cultivation by farmers of Sikkim Himalayas and similar agroecoregions under organic production system.

Role of environmental variables and seasonal mixing in dynamics of the phytoplankton community in a Tropical Highland Lake Ardibo, Ethiopia

This study aimed to assess the spatial and seasonal variations of the phytoplankton community in response to environmental variables in Lake Ardibo. The study was done from October 2020 to September 2021 and physicochemical parameters such as water temperature, pH, dissolved oxygen, electrical conductivity, turbidity, alkalinity, Secchi-depth, nitrate, ammonium, silicon dioxide, soluble reactive phosphorus, and total phosphorus were measured using standard methods. ANOVA results indicated that all physicochemical parameters except turbidity had significant variation (p < 0.05) in all seasons. A total of 66 phytoplankton species grouped into seven phyla, including Bacillariophyta (23 taxa), Chlorophyta (21 taxa), Cyanophyta (14 taxa), Euglenophyta (3 taxa), Charophyta (2 taxa), Dinophyta (2 taxa) and Cryptophyta (1 taxon) were identified. Phytoplankton biomass showed significant spatial and seasonal variation with maximum cell density during the pre-rainy season, and low density in the main rainy season. Redundancy analysis (RDA) revealed that nutrients had a positive affinity with the phytoplankton community, whereas electrical conductivity, water temperature, and pH showed a negative relationship with phytoplankton abundance. Temporal rather that abiotic factors far influenced phytoplankton dynamics in this deep tropical lake. The analysis postulates that partial atelomixis during the pre-rainy months favors higher phytoplankton biomass with functional groups such as desmids and heavy diatoms contributing most during this mixing period, while wet season mixing depressed algal biomass due to increased turbidity with nutrients not being limiting during these times.

Effect of biochar levels and integrated nutrient-management practices on agro-physiological performance and productivity of maize (Zea mays)

The experiment was laid out in a factorial randomized block design, during the pre-rainy season of 2018 and 2019 at ICAR Research Complex for North Eastern Hills Region, Umiam, Meghalaya, to study the effect of biochar and integrated nutrient management practices on agro-physiological performance and productivity of maize (Zea mays L.). comprising 4 treatments, viz. B1 , (Control); B2 , (5 t/ha biochar); B3 , (10 t/ha biochar); B4 , (15 t/ha biochar) in factor A and factor B having 3 integrated nutrient-management (INM) practices NM1 [(100% recommended, viz. dose of nitrogen (RDN)]; NM2 [(75% RDN + 25% FYM)]; NM3 (50% RDN + 50% FYM), in 3 replications. The results showed that an application of biochar @ 15 t/ha resulted in significantly higher plant height (171.4 and 177.1 cm) and dry-matter accumulation (393.1 and 401.5 g/plant) at harvesting stage, leaf area index (LAI) at 60 days after sowing (4.78 and 4.85) and 90 days after sowing (DAS) (5.45 and 5.52), crop-growth rate (CGR) at 30–60 days after sowing (37.3 and 38 g/m2/day). This treatment also resulted in significantly higher kernel/cob (267.8 and 275.8), rows/cob (20.7 and 21), kernel/row (19.9 and 21.8), kernel (4.43 and 4.49 t/ha) and stover yield (7.02 and 7.07 t/ha), total nitrogen uptake (141.8 and 140.4 kg/ha), total phosphorus uptake (23.8 and 23.6 kg/ha), total potassium uptake (115.9 and 114 kg/ha) and gross returns (102,664 and 104,023 `/ha) in 2018 and 2019 as compared to the other treatments. In the case of INM practices, significantly higher plant height (161.6 cm) and drymatter accumulation at the harvesting stage (367.2 g/plant), leaf area index at 60 days after sowing (4.60) and 90 days after sowing (5.23), crop growth rate (34 g/m2 /day) at 30–60 days after sowing, kernels/cob (234.9), rows/cob (18.4), kernel/row (19.0), kernel (4.15 t/ha) and stover yield (6.56 t/ha), total nitrogen uptake (125.6 kg/ha), total phosphorus uptake (21.4 kg/ha), total potassium uptake (100.7 kg/ha) and gross return (95,931 `/ha) were noticed under 75% RDN + 25% FYM during the first year, while during the second year significantly higher plant height (167.6 cm) and dry-matter accumulation at harvesting stage (375.7 g/plant), leaf area index at 60 days after sowing (4.69) and 90 days after sowing (5.31), crop growth rate (35.2 g/m2 /day) at 30–60 days after sowing, kernels/ cob (241.0), rows/cob (18.7), kernel/row (20.8), kernel (4.25 t/ha) and stover yield (6.63 t/ha), total nitrogen uptake (125.1 kg/ha), total phosphorus uptake (21.5 kg/ha) and total potassium uptake (99.1 kg/ha) were recorded under 50% RDN + 50% FYM than the control, but gross returns (95,931 `/ha) were noticed under 75% RDN + 25 FYM. The best alternative choice for maize production in the India Himalayan area or other similar ecoregions may be the use of biochar @ 15 t/ha together with the concomitant application of 50% RDN + 50% FYM.

Pre-rainy Season Rainstorms in South China—Risk Perception of the 11 April 2019 Rainstorm in Shenzhen City

With the acceleration of urbanization in South China, rainstorms and floods are threatening the safety of people in urban areas. The 11 April 2019 (4·11 hereafter) rainstorm in Shenzhen City was a typical pre-rainy season rainstorm that caused great damage, yet such pre-rainy season events have not attracted sufficient attention in research. Risk perception of the public may indirectly affect their disaster preparedness, which is important for disaster management. In this study, we conducted a questionnaire survey that considered demographic factors and the level of risk perception, knowledge of risk, impact of the 4·11 rainstorm event on public risk perception, and degree of trust in the government. We used a two-factor model of risk perception to evaluate the factors that influenced public risk perception of the 4·11 rainstorm in Shenzhen. The main conclusions are: The 4·11 rainstorm improved public awareness of both risk and impact through the medium term, but the public’s perceived low probability of disaster occurrence and lack of knowledge of the pre-rainy season rainstorm phenomenon led to serious losses during this event. Although the public has high trust in the Shenzhen government, the management of rainstorm disasters in the pre-rainy season needs to be further improved.

A Joint Impact on Water Vapor Transport over South China during the Pre-Rainy Season by ENSO and PDO

Based on precipitation data from 60 stations in South China (SC) and NCEP reanalysis data, the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT_4.9) is used to analyze the difference of water vapor transport tracks, water vapor sources, and their precipitation contribution rate to frontal/monsoon precipitation, with four combinations of ENSO and PDO phase for a period of 53 years (1960–2012). The results show that: (1) For the frontal precipitation, in the Pacific Decadal Oscillation positive phase (PDO+), there is a great positive water vapor difference between ENSO+ (the positive ENSO phase) and ENSO− (the negative ENSO phase) over the tropical Indian Ocean (IO), the Bay of Bengal (BOB), the South China Sea (SCS) and the western Pacific (WP), the distribution of the difference is adjusted for PDO− (the negative PDO phase). For monsoon precipitation, when PDO and ENSO are in phase resonance, water vapor gathers over IO-BOB-SCS. (2) For the frontal precipitation, both PDO+ and PDO−, compare with ENSO+, more water vapor from SCS for ENSO−, but the southward water vapor transport anomaly over the western part of BOB-SCS-ocean east of the Philippines, which leads a decline in precipitation contribution rate of SCS water vapor. Both ENSO+ and ENSO−, compare with PDO−, more water vapor comes from IO-BOB for PDO+, but their precipitation contribution rates are lower. (3) For the summer monsoon precipitation, SCS and IO are important rain contributor sources. Regardless of the PDO phase, compared with ENSO+, there is more water vapor from the IO and WP for ENSO−, the easterly anomaly in the south of the stronger subtropical high brings more water vapor from WP to SC, the strong westerly anomalies in the IO-BOB-SCS increases IO water vapor transporting to SC, so water vapor precipitation contribution rates of IO and WP are higher. Both ENSO+ and ENSO−, compare with PDO−, more water vapor comes from SCS and EC for PDO+, but their precipitation contribution rates are lower. (4) The water vapor transport process of precipitation in PFS over SC is jointly affected by ENSO and PDO.

SEASONAL VARIATION IN WATER QUALITY INDEX OF THE LAKE BOSOMTWE BIOSPHERE RESERVE

Lake Bosomtwe has been subjected to anthropogenic perturbations that provide different scales of environmental stimuli in response to seasonal variation. This situation can overwhelm the capacity of lake to mitigate the impact on the water quality. Knowledge of seasonality will enhance the predictability of the water quality trends to advance management of the lake. The seasonal pattern of levels of physicochemical and nutrient parameters was examined, from March 2018 to February 2020, using the Canadian Council of Ministers of the Environment Water Quality Index model. Temperature, pH, alkalinity, turbidity, dissolved oxygen, total hardness, total dissolved solids, total suspended solids, biochemical oxygen demand, nitrate, phosphate, sulphate, iron, lead, and zinc were studies. The results showed a decline in water quality from ‘fair’ status in the pre-rainy (65.7%) and rainy (67.2%) seasons through ‘marginal’ in the pre-dry seasons (46.5%) to poor in the dry seasons (44%). The lake is therefore losing its natural protection to the extent of occasional for the pre-rainy and rainy seasons, frequently for pre-dry seasons, and almost all the time for dry season, the period of low lake water volume and availability and hence high dependence. Thus, the threat of human and ecological health hazard associated with aquatic pollution is ordered by seasonality; being heightened in the dry season with alkalinity, sulphate, iron, temperature, total suspended solids and turbidity as the parameters of more concern. This provides adequate ground for a call for elaborate and systematic plan of action to manage the lake for sustainability.

The role of live chicken markets as a source of replication and dissemination of Newcastle disease virus in chickens, northwest Ethiopia

Newcastle disease (ND) is perceived to be the major constraint in village chickens of Ethiopia causing huge economic loss. Village chickens are mobile and pass through markets, and live chicken markets are a highly productive source of ND virus replication, maintenance, and spread. However, in northwest of Ethiopia, there is a dearth of information on the role of live chicken markets in the maintenance and spread of ND in the village chickens. Therefore, a total of 480 apparently healthy chickens in the 4 live chicken markets were sampled with the aim to detect and estimate ND virus infection. Tracheal and cloacal swabs were collected from each bird and processed for virus isolation in 9- to 11-day-old embryonated chicken eggs, and hemagglutination inhibition (HI) assay was performed on all sera samples. The overall infection rate of ND virus was reported to be 39.2% (95% CI: 34.8–43.5). Of all chickens, 34.6% (95% CI: 30.3–38.9) had mean HI titer ≥4 log2, which was considered as protective. The mean hemagglutination titer for the ND virus was reported to be 6.0 log2, and mean antibody titer was reported to be 6.2 log2, with no statistically significant variation among the markets (P > 0.05). Newcastle disease occurrence was detected in all seasons of the year in the live bird markets, with the highest prevalence (55.8%) during the prerainy dry season (April and May), showing evidence for climatic and socioeconomic aspects as a risk factor in the occurrence of ND in indigenous chicken. In vivo virulence tests, mean death time of the embryo, and the intracerebral pathogenicity index revealed the presence of all pathotypes of ND virus strains: velogenic, mesogenic, and lentogenic. Apparently, healthy appearing birds were reported to be reservoirs of velogenic ND virus strains that could initiate endemicity of ND cycles in the village setting. Hence, it is strongly recommended to implement appropriate prevention and control measures to mitigate the economic loss caused by the disease.

Model Uncertainty Representation for a Convection-Allowing Ensemble Prediction System Based on CNOP-P

Formulating model uncertainties for a convection-allowing ensemble prediction system (CAEPS) is a much more challenging problem compared to well-utilized approaches in synoptic weather forecasting. A new approach is proposed and tested through assuming that the model uncertainty should reasonably describe the fast nonlinear error growth of the convection-allowing model, due to the fast developing character and strong nonlinearity of convective events. The Conditional Nonlinear Optimal Perturbation related to Parameters (CNOP-P) is applied in this study. Also, an ensemble approach is adopted to solve the CNOP-P problem. By using five locally developed strong convective events that occurred in pre-rainy season of South China, the most sensitive parameters were detected based on CNOP-P, which resulted in the maximum variations in precipitation. A formulation of model uncertainty is designed by adding stochastic perturbations into these sensitive parameters. Through comparison ensemble experiments by using all the 13 heavy rainfall cases that occurred in the flood season of South China in 2017, the advantages of the CNOP-P-based method are examined and verified by comparing with the well-utilized stochastically perturbed physics tendencies (SPPT) scheme. The results indicate that the CNOP-P-based method has potential in improving the under-dispersive problem of the current CAEPS.

Retrospective Study of Newcastle Disease Cases Diagnosed at the ‎Veterinary Teaching Hospital, Ahmadu Bello University, Zaria, Nigeria

Newcastle Disease (ND) is a contagious viral disease of birds affecting many domestic and wild avian species. Even though vaccines and vaccination schedules are currently being employed in the prevention of the disease, prevention and control are still a problem in the poultry industry. This study was conducted at the Veterinary Teaching Hospital (VTH), Ahmadu Bello University (A.B.U), Zaria and the aim was to determine the monthly, yearly and seasonal prevalence of ND diagnosed in the Avian Clinic of the VTH, A.B.U., Zaria. Case record files were collected, studied, and clinically diagnosed cases of ND for five years (2014-2018) were extracted. Diagnosis of ND was by history of the case, clinical findings and post mortem lesions observed. Results showed that out of 1,768 cases of poultry presented, 42.6% (754 cases) were confirmed via necropsy findings as ND. The highest number of cases of the disease was in June having a prevalence of 4.98% followed by March with a prevalence of 4.64% and July with a prevalence of 4.47%. The annual prevalence was highest in 2014 (14.82%). The cases of ND were observed to be higher in the pre-rainy season (April to June) with a prevalence of 12.33%. The environmental stress condition of these periods of the year was likely to be the main reason that potentiate and worsen the occurrence of ND at these periods. Also, stress condition suppresses the immune system of birds making them more susceptible to infection leading to an outbreak of disease. It is recommended to administer anti-stress before these periods in order to protect the birds from the disease.

Seasonal variation of rhizospheric soil properties under different land use systems at lower Shivalik foothills of Punjab, India

The rhizosphere is the unique hotspot that is highly influenced by plant roots and characterized by higher microbial activity and nutrient availability. Land uses modify the rhizospheric soil properties through the stimulatory effects of various root exudates and soil nutrients. The present work was aimed to study rhizosphere soil properties under different land use systems at Ballowal Saunkhri watershed in Punjab state, India. For this study, soil samples were collected from three land use systems (horticulture, farm forest and cropland) at four depths, viz. 0–15, 15–30, 30–60 and 60–90 cm during pre-rainy and post-rainy seasons. The results indicated that farm forestry system had significantly higher soil organic carbon (SOC), cation exchange capacity, micronutrient cations (Zn, Fe, Cu, Mn) and microbial properties (total microbial count, microbial biomass carbon, basal soil respiration, dehydrogenase activity, alkaline phosphatase activity and microbial quotient) compared with other land use systems. However, bulk density, available phosphorus, available potassium and metabolic quotient were observed higher under cropland system. The principle component analysis identified that SOC and available potassium were the most contributing and reliable variables for assessing soil quality for different land use systems.

Strength of Linkages Between Dust and Circulation Over North Africa: Results From a Coupled Modeling System With Active Dust

AbstractNorth African dust aerosol and climate are known to covary, but modeling studies are uncertain as to whether this covariation arises from a positive feedback loop. This study aims to improve our understanding of the strength of the relationship between dust and climate over the Sahel. A fully coupled meteorology‐land‐aerosol model (NU‐WRF) is applied to simulate mineral dust emission and transport over North Africa from prerainy season to postrainy season (March–October) for the years 2002–2016; results are compared to estimates from the MODerate Resolution Imaging Spectrometer (MODIS), the NASA Modern‐Era Reanalysis for Research and Applications v2 (MERRA‐2), the MERRA‐2 Global Modeling Initiative (GMI), and the Aerosol Robotic Network (AERONET). Two model configurations (Dust‐On and Dust‐Off) are used to investigate the regional dust‐atmosphere coupling during the Sahelian rainy season by assessing the influence of land surface conditions and near‐surface meteorology on dust emission, and the impacts of dust on the atmospheric circulation features linked to climate and dust variability. Results show that coupling appears to be weak on interannual timescales, as interannual variability in dust load and dust impacts on atmospheric circulations is modest. NU‐WRF captures the general spatial and temporal variability in dust, though it underestimates the burden during dusty months, as compared to observational and reanalysis products. Model emission and transport processes during the dustiest months are consistent with other data products, and differences appear to be wind driven. Though the impacts of mineral dust on climatological summertime atmospheric circulation patterns are small, these impacts are consistent with weakened monsoon flow and a southward narrowing of the rain belt.

Assessing Changes in Ecological Quality Status of Sediment in Tri An Reservoir (Southeast Vietnam) by using Indicator of Nematode Communities

Nematode communities in Tri An Reservoir (Dong Nai Province, Southeast Vietnam) were explored in the dry season (March) and pre-rainy season (July) of 2019 and analyzed to evaluate their usage as bioindicators for ecological quality status of sediment. Nematode communities consisted of 23 genera belonging to 19 families, 8 orders for the dry and 24 genera, 17 families, 8 orders for the pre-rainy season. Several genera dominated in Tri An Reservoir such as Daptonema, Rhabdolaimus, Udonchus, and Neotobrilus indicated for organic enrichment conditions. The percentage of cp3&amp;4 and MI (Maturity Index) value in the dry season was higher than that in the pre-rainy season expressed the ecological quality status of sediment in the dry season were better than those in the pre-rainy season. Furthermore, the result revealed that MI and c-p% composition can be used to evaluate the ecological quality status of sediment efficiently.&#x0D; Keywords: Bioindicator, ecological quality status of sediment, freshwater habitats, maturity index, nematodes, reservoir.

Traditional green leafy vegetables as underutilised sources of micronutrients in a rural farming community in south-west Nigeria II: consumption pattern and potential contribution to micronutrient requirements

Objective: To determine the consumption pattern of selected households consuming traditional green leafy vegetables (TGLVs) during three seasons and potential contribution to recommended nutrient intakes. Design: Repeated household survey using food frequency questionnaire to obtain consumption pattern of selected TGLVs. Setting and Subjects: Selected households in a small rural farming community: pre-rainy (n = 43), rainy (n = 36) and post-rainy seasons (n = 40). Results: Corchorus olitorius and A. hybridus were the most consumed by > 70% of households across three seasons. A. esculentus and A. viridis were the least consumed TGLVs through all the seasons. Uncultivated and cultivated TGLVs could contribute between 26–> 100% and 18–96%, respectively, of recommended intake for vitamin A for children and women. For young children, both the cultivated and uncultivated TGLVs could contribute more than 50% of their RDA for iron. Conclusion: seasonal availability, and preference for certain species, determine the consumption pattern of the TGLVs studied. Uncultivated and less utilised vegetables have the potential to make significant contributions to the micronutrient requirements of women and children, especially vitamin A and iron if frequently used.