South India Research Articles

Histopathologic Perspective of Nail Lichen Planus: A 10-year Case Series From a Tertiary Care Center in South India.

Nail involvement is seen in 10% of lichen planus patients, with a subset developing severe destruction of the nail matrix. Nail biopsy is a complex procedure usually done when nails are the only site of involvement. The pathology of nail lichen planus (NLP) has been the subject of very few studies. Most studies refer to the major and minor histopathologic criteria proposed by Hanno et al. This study aims to characterize the histopathologic features of NLP. Twenty five patients of NLP with nail biopsies, diagnosed in the last 10 years were included in the study. Lichen planus was suspected in all patients, and the alternative diagnosis was psoriasis/onychomycosis and melanoma. On histopathology, the common features included acanthosis (88%), lichenoid lymphocytic inflammation (96%), and hypergranulosis (72%). Detachment of epithelium from the subepithelium, a hitherto unreported feature, was noted in 60% of cases. Less common features were lymphocytic exocytosis (48%), melanophages (40%), basal vacuolar alteration (24%), apoptotic keratinocytes (28%), fraying of the nail plate (24%), and spongiosis (20%). Understanding the common and less common histopathologic features and their correlation with clinical findings is essential to diagnose NLP accurately rather than stressing histologic criteria as major/minor, which may lead to the underdiagnosis of cases.

Unveiling Efficiency: A Research Inquiry into Technical Staff Utilization in South Indian Clinical Laboratory using Workload Indicators Staffing Need (WSN) Analysis.

Background Effective clinical laboratories are the need of the hour, they play a significant role in healthcare, providing tests for diagnosis, treatment monitoring. Having skilled and adequate staffing is crucial for clinical laboratories to operate efficiently, manage their workload effectively, and deliver test results in a timely manner. Despite being critical for healthcare delivery, ensuring adequate staffing levels in clinical laboratories remains a complex challenge for healthcare providers worldwide due to resource constraints and workforce shortages. Methods This study evaluates the effectiveness of clinical laboratory staff utilization by considering workload, work pressure, and staffing requirements. We utilized the Workload Indicators of Staffing Need (WISN) method to assess the staffing in the clinical laboratory of a tertiary care hospital. Annual hospital statistics were collected for two years from June 2021 to May 2023 to calculate the average number of days (234) worked annually, percentage of workload, distribution of activity time measurement units, and the ratio of needed, surplus, and existing staff. The findings aim to provide valuable insights for optimizing staffing levels and ensuring an efficient laboratory environment. Result The analysis found a significant workforce gap in the laboratory between the current staff numbers and the calculated staffing needs. The WISN ratios ranged from 0.2 to 0.7, indicating the existing 33 staff members face a high workload burden. The calculated ideal staffing level was 46.33 personnel. These results demonstrate staff shortage and excess workload pressure on the current laboratory employees. Conclusion The results highlight the importance of optimizing staffing levels in clinical laboratories to ensure quality service delivery. The WISN methodology can be a useful tool in healthcare facilities for making evidence -based decisions for staff allocation, maximizing the utilization of employee skill sets, and establishing standard staffing benchmarks tailored to the needs of clinical laboratories.

Genetic variants in BDNF (rs6265 and rs11030119) and stroke susceptibility: a case-control analysis in South India

Background Stroke occurs when the blood supply to part of the cerebral cortex is blocked, depriving it of oxygen and glucose, leading to cell death. It is a multifactorial disorder influenced by genetic, vascular, and environmental factors. Aim This study investigated the association between two polymorphisms of the brain-derived neurotrophic factor (BDNF) gene, rs6265 and rs11030119, and stroke risk in a South Indian population. Subjects and Methods The study included 163 stroke cases and 160 healthy controls. Genomic DNA was extracted, and genotyping of rs6265 and rs11030119 polymorphisms was done using ARMS-PCR. Allelic and genotype frequencies were calculated, and odds ratios (OR) with 95% confidence intervals (CI) were determined using SPSS version 21.0. Results The rs6265 polymorphism was significantly associated with stroke risk, with the GG genotype more frequent in controls (OR 1.79, 95% CI 1.05–1.76, p = 0.01). The rs11030119 polymorphism showed a positive association, with the AA genotype more prevalent in cases (OR 2.70, 95% CI 1.34–5.44, p = 0.003). Conclusion This study suggests an association between BDNF polymorphisms (rs6265, rs11030119) and stroke risk in a South Indian population. Further research in larger populations is necessary to confirm these findings and explore the mechanisms involved.

Managing Amitraz Poisoning: Epidemiological Data and Clinical Insights From a Tertiary Care Hospital in Southern India

Managing Amitraz Poisoning: Epidemiological Data and Clinical Insights From a Tertiary Care Hospital in Southern India

Effective weed control through post-emergence herbicides to enhance blackgram (Vigna mungo L.) productivity in South India

Pulses are essential components of vegetarian diet and play a pivotal role in addressing malnutrition by providing a vital source of dietary protein. However, weed competition remains as a significant obstacle to blackgram (Vigna mungo L) production, resulting in 25 to 35% yield losses. A field experiment was carried out at the National Pulses Research Centre, Tamil Nadu Agricultural University, Vamban, Pudukkottai, India during Kharif seasons of 2020 and 2021, to assess the suitable post-emergence herbicides for appropriate weed control in blackgram grown under irrigated conditions. The experimental field was observed to contain notable grass weed flora, specifically Dactyloctenium aegyptium and Chloris barbata, as well as broadleaved weeds, such as Flaveria australica, Cleome gynandra, Eclipta alba, Convolvulus arvensis, Digera arvensis, Vicia spp., and Celosia argentea. The results demonstrated that among the chemical weed management methods, spraying of Fomesafen @ 220 g + Fluzifop p-butyl @ 220 g ha−1 at 20 days after sowing (DAS) as a post-emergence herbicide treatment exhibited superior weed control efficiency, recording 66.80% and 68.53% at 30 and 45 DAS, respectively and recorded higher seed yield of 1088 kg ha−1. Additionally, this method generated 8.1% higher net income and 12.5% more benefit–cost ratio than hand weeding, making it an economically profitable strategy for maximizing blackgram yield and effective labour management.

The Impact of Plant Diversity on Spider Populations in a Tropical Butterfly Conservatory, Tiruchirappalli, South India

Spiders, as crucial predators and biodiversity indicators, significantly influence ecosystem health. This study investigates the intricate relationship between plant diversity and spider communities within distinct habitats of the Tropical Butterfly Conservatory, Tiruchirappalli, India. By classifying spiders based on their hunting strategies, we aim to understand their ecological roles. This research establishes a baseline for the spider fauna within the conservatory, emphasizing the impact of plant life on spider diversity and distribution. Our findings contribute to a comprehensive evaluation of the ecological importance of spiders in this unique ecosystem, providing valuable insights for future conservation and management efforts. By unravelling the complex interplay between plants and spiders, this study underscores the necessity of preserving plant diversity to sustain a robust and balanced spider community.

Genetic Evaluation of Monthly Test-Day Milk Yields of Jersey Crossbred Cattle Under Farmers' Production System in Tamil Nadu, India.

Tamil Nadu, a state in southern India, is bereft of any native dairy or dual-purpose cattle breeds, and the state depends chiefly on crossbred cattle for milk production. Jersey crossbred cattle account for 90% of the state's milk production. This genetic evaluation study aimed to assess milk production traits, including test-day milk yields (TDMYs), total lactation milk yield (TMY), and 305-day milk yield (305MY), in these cattle reared under farmers' conditions. Data on monthly TDMYs (TDMY1 to TDMY10) of Jersey crossbred cows (n = 75,627) reared by the farmers over 11 years (2012-2022) were collected for evaluation. The influence of non-genetic factors viz., location (agroclimatic zones), period and season of calving, and parity on TDMYs, TMY and 305MY were assessed, and the variance and covariance components for genetic parameters (heritability and genetic correlation) of the traits were estimated by the method of restricted maximum likelihood (REML) under a multivariate animal model and by a random regression model (RRM). The overall means of various TDMYs ranged from 4.98 (TDMY10) to 9.95 kg (TDMY2), and for TMY and 305MY, the means were 2480.33 and 2393.71 kg, respectively. The heritabilities estimated by the multivariate animal model for TDMYs were moderate and ranged from 0.26 ± 0.02 to 0.37 ± 0.02 and the estimates were less variable throughout lactation, while the estimates obtained by RRM were medium to high and ranged between 0.29 ± 0.01 and 0.67 ± 0.02 for milk yield on day 5 to 305 (DIM 5-DIM 305). The heritabilities estimated for TMY and 305MY were 0.43 ± 0.02 and 0.43 ± 0.02, respectively. The estimates of heritability for mid-lactation yields were comparatively less than those at the beginning and the end of lactation. The moderate to high estimates of heritabilities for TDMYs, TMY, and 305MY obtained in the present study offer ample scope for improving milk production through selective breeding. Genetic correlations between TDMYs estimated by the multivariate animal model were positive and high, with a range between 0.75 ± 0.03 and 0.99 ± 0.00. Considerably higher estimates (0.98-0.99) were observed between adjacent TDMYs showing strong genetic associations. By RRM, genetic correlations estimated between DIMs were positive (except for DIM 5 with DIM 125 to DIM 185 and DIM 125 with DIM 305), and the magnitude of genetic correlation decreased with an increase in the interval between the DIMs. The high genetic correlation observed between the TDMYs (in the early stage of lactation) and total lactation milk yield suggested that these test-day yields could be used favorably for the early selection of cows for milk production, which facilitates reduction in the generation interval and consequently increases the annual genetic gain for the milk production traits.

Pattern of Tinnitus and Its Risk Factors Among Individuals with Tinnitus in South India

Pattern of Tinnitus and Its Risk Factors Among Individuals with Tinnitus in South India

Pollution assessment, ecological risk and source identification of heavy metals in paddy soils and rice grains from Salem, South India

The present study investigated concentrations of metals (Cu, Zn, Fe, Mn, Ni, Pb, and Cd) in paddy soils and rice tissues of nine different widely used indica rice varieties in Salem district, India. The order of DTPA soil available metal contents (mg kg-1) were Fe (33.50) > Mn (8.86) > Cu (2.58) > Pb (1.99) > Zn (1.67) > Ni (1.48) > Cd (0.13). Pollution load index (PLI) levels for Cd (1.28) were ‘moderately polluted’, contamination factor (CF) and enrichment factor (EF) values for all metals showed ‘medium contamination’ and ‘less enrichment’ except for Cu and Pb. Ecological risk factor (ERF) and potential ecological risk index (PRI) values of Cd (31.94 and 287.50) showed ‘moderate risk’ and ‘strong ecological risk’. Bio-accumulation factor (BAF) levels of Cd (48.12) and Pb (27.89) are classified as ‘high concentrators’. Translocation factor (TF) values of Pb (2.9), Cd (2.5) and Ni (1.7) were greater than one for roots to plants. Children had higher target hazard quotient (THQ) and hazard index (HI) values for Cd, Pb and Ni than adults. Principal component analysis (PCA) revealed with all parameters that they fell within the two primary factors 1 and 2, with an eigenvalue of 4.69 (33.52% variation) and 3.73 (26.66% variation), respectively. However, cluster analysis (CA) revealed three distinct groups between the metals studied. Although the soil metal contents were within the permissible levels, the grain Cd (6.07 mg kg-1), Pb (56.20 mg kg-1), and Fe (116.11 mg kg-1) contents in all the rice varieties exceeded the prescribed limits of 0.4, 0.2, and 15 mg kg-1, respectively. Our findings will provide important data for metal enrichment in soils to implement more effective measures to reduce the contamination of metals in paddy fields.

Multivariate statistical and hydrogeochemical analysis of seasonal groundwater quality variations in coastal villages of Trivandrum district, south India

This study attempts a detailed assessment of the quality of groundwater in the coastal region of Trivandrum District, Kerala where groundwater is the main source of drinking water. Forty groundwater samples were collected during the pre-monsoon and post-monsoon periods. The collected samples were analyzed for physical properties such as electrical conductivity (EC), pH, total dissolved solids (TDS), and total hardness, along with chemical properties, including major cations (Ca2⁺, Mg2⁺, Na⁺, K⁺) and anions (Cl⁻, SO₄2⁻, HCO₃⁻, NO₃⁻). The analysis of groundwater quality reveals significant spatial and seasonal variations caused by both natural and manmade influences. Water Quality Index (WQI), hydrogeochemical plots, and Principal Component Analysis (PCA) were used to analyses the data. The results show that Vakkom, Kazhakottam, Veli-Attipara, and Pozhiyoor show significant deterioration, and areas such as Varkala, Ayroor, and Edava generally maintain good water quality. The Water Quality Index (WQI) assessment indicates that approximately 22.5% of the studied area falls under excellent quality, while 17.5% is classified as poor. The WHO standard and BSI standards were used to derive the WQI. Principal Component Analysis (PCA) identified electrical conductivity, total dissolved solids, and total hardness as the primary factors affecting groundwater quality, explaining 65.17% and 61.03% of the total variance in the pre-monsoon and post-monsoon periods, respectively. Hydrochemical plots collaborate these results, emphasize the influence of rock-water interactions as the main geochemical process, further compounded by pollution from agricultural runoff and urban development. These findings highlight the need for sustainable groundwater management strategies in coastal communities. Effective measures, including pollution mitigation, sustainable agricultural practice, proper waste management, and preservation of freshwater ecosystems, are essential for ensuring the sustainability of groundwater resources.

Antifungal resistance, clinical outcome and clinico-microbiological correlation in ocular infections due to common melanized fungi Curvularia lunata and Lasiodiplodia theobromae in South India.

Aim. Melanized fungi were rarely studied for their antifungal resistance (AFR) or clinical outcome, despite rising incidence of melanized fungal ocular infections and AFR in general. We report the antifungal resistance patterns, clinical outcome and clinico-microbiological correlation in two commonly isolated melanized fungi from ocular infections, Curvularia lunata and Lasiodiplodia theobromae, at a tertiary eyecare centre in South India.Gap statement. Despite melanized fungi accounting for a significant proportion of ocular fungal infections in the Indian subcontinent, and despite there being a limited selection of effective antifungal agents available for these infections, the existing data and studies on these issues remain sparse. Therefore, this study aimed to investigate the prevalence of antifungal resistance in two of the most common melanized fungal pathogens in ocular infections, Curvularia lunata and Lasiodiplodia theobromae and correlate it with the treatment given and the clinical outcome in patients.Methodology. Electronic medical records provided the clinical data. Standard broth microdilution was performed for antifungal susceptibility testing (AFST) in 30 isolates (17 C. lunata and 13 L. theobromae) for amphotericin B and natamycin (polyenes): voriconazole, ketoconazole, posaconazole, itraconazole and fluconazole (azoles) and caspofungin (echinocandin). Multidrug resistance (MDR) was defined as resistance to more than or equal to two classes of antifungals. DNA sequencing was performed for the isolates for species confirmation. The multivariate analysis was done for determining poor prognostic factors.Results. AFST showed highest susceptibility of study isolates for voriconazole (83.3% isolates), followed by natamycin (80%), fluconazole (80%), itraconazole (76.7%), ketoconazole (70%), posaconazole (66.7%), caspofungin (66.7%) and lastly amphotericin B (63.3%). All patients empirically received topical natamycin; additional oral ketoconazole/intraocular voriconazole was administered in select few. MDR was strongly associated with poor clinical outcome (multivariate analysis: P = 0.03, odds ratio = 7.8). All patients had microbial keratitis, one progressed to endophthalmitis. Additionally, therapeutic penetrating keratoplasty was required in 40% of cases. Globe salvage was possible in 80% patients, though good visual outcome was seen in only half of them. Both, anatomical and visual outcomes, were poor in 20% of patients. DNA sequencing showed C. lunata as the highest study species.Conclusion. C. lunata and L. theobromae showed varying in vitro antifungal susceptibility and clinical outcome in ocular infections. Voriconazole had significantly higher activity, while amphotericin B had lower activity in vitro for these melanized fungi. MDR isolates showed poorer clinical outcome.

Challenges and Opportunities in Deceased Organ Donation Program: Insights from a Tertiary Care Hospital in South India

Background: Organ transplantation is a critical medical intervention for patients with end-stage organ failure. Deceased organ donation plays a pivotal role in meeting the demand for organs. However, there exists a significant disparity between the need for organs and their availability, especially in low-income countries. India, despite its potential donor pool, faces a severe shortage of organs for transplantation. Materials and Methods: This retrospective study analyzed hospital records of 116 potential deceased organ donors from 2013 to 2020. Data encompassed demographics, next-of-kin consent for organ transplantation, and circumstances of injury. Results: Results revealed that 85.34% of potential donors were men, and 14.66% were women. After counseling, 71.55% (83/116) of the families consented to deceased organ donation. Most potential donors fell within the 21–30 age group (25.88%). The majority of donors (80.17%) died due to road traffic accidents (RTAs), primarily two-wheeler drivers constituted the largest group of deceased (51.72%). Conclusion: Bridging the gap between organ demand and supply in India necessitates addressing the lack of awareness regarding brain death and organ transplantation. Collaborative efforts involving NGOs, healthcare institutions, media, and government bodies are essential to raise awareness and improve donation rates, especially in public health centers. Establishing guidelines for compassionate discussions with families about organ donation is imperative.

Neuromelioidosis – A retrospective review of thirteen cases from a tertiary care centre from South India

Neurologic melioidosis warrants attention in view of its rarity and lethal consequences. We performed a retrospective review of culture confirmed neurologic melioidosis reported between 2017 and 2023. Thirteen patients were identified with median age 43 years and all but three were males. Brain parenchyma was involved in 57% cases (7/13) as cerebritis, encephalitis and macro abscess or micro abscess. Three patients had myelitis with spinal cord micro abscess and cerebral venous thrombosis in three other patients. Five patients died during hospitalization. Two were discharged against medical advice due to financial constraints. Six survivors were followed between one and eight months.

Impact of urbanization on soapnut Sapindus trifoliatus L. tree cover and the need for community involvement: a case study from Kochi, Kerala, India

ABSTRACT The South Indian soapnut tree, Sapindus trifoliatus L, is a midsized evergreen tree from the Indian subcontinent whose fruit can produce natural detergents, biodiesel, and biopesticides. In this study, we document the systematic destruction of soapnut trees through a citizen-supported tree census in an emerging Tier 2 city, Kochi, in South India. In the study, 3580 respondents allowed us to find and map 210 locations of soapnut trees across 411.57 km2. Kochi expanded suddenly in the early 2000s, with a drastic increase in built-up area (126%) and a steady decline in wetlands (57.6%) and croplands (15%). Habitat loss and removal from home gardens has quartered soapnut tree density, to 0.11 km−2. With only 50 trees remaining, the population of the South Indian soapnut will reach the brink of local extinction by 2080.

Concordance of Bronchoscopic and Radiological Findings in Suspected Lung Cancer and its Outcome- A Cross Sectional Study in a Tertiary Care Hospital

Background: Bronchoscopy and CT thorax are the most common investigations utilized to screen and diagnose lung cancer. Their individual utility in diagnosing lung cancer has been described affirmatively in existing literature. Studies correlating the airway characteristics of the two modalities in lung cancer are limited. Objectives: To analyze and characterize lung lesions bronchoscopically and correlate the same radiologically by CT of the thorax and thus assess its positive predictive value. Methods: In this prospective study, 56 consecutive adults who presented to the Respiratory Medicine Department at a tertiary care hospital in South India from November 2018 to June 2020, having Clinico-radiological suspicion of malignancy and fulfilling study criteria, were recruited. They were subjected to CECT of thorax and bronchoscopy. All bronchoscopic procedures were performed using a protocolized number of passes for biopsy. The baseline demographic and clinical data, findings of bronchoscopy and CT and biopsy reports were recorded. Cohen’s kappa coefficient was used to estimate the agreement of findings on the two modalities. Statistical analysis was performed using SPSS software. Results: Bronchoscopy was normal in 22.14% of cases, the corresponding CTs also revealed normal airway. Bronchoscopy revealed airway lesions in 78.6% of cases; the corresponding CT revealed airway abnormalities in only 46.41% of cases; among these, 52.1% of cases revealed an exophytic growth. There was fair strength of agreement for the two modalities in the detection of airway lesions of lung cancer. (k = 0.38, p = <0.001). CECT thorax has a negative predictive value of 44%, a sensitivity of 59.1% and a specificity of 100% at 95% CI in the detection of airway lesions. Conclusion: CT may not be definitive in the evaluation of lung cancer, especially in those with central disease. A combination of the two modalities may improve the diagnostic outcome in patients with lung cancer.

Relationship between proxy behavior in clinic attendance and disease control among persons with hypertension and diabetes at a rural primary health center: A cohort analysis in South India

ABSTRACT Aims: Among persons with hypertension and diabetes on treatment for at least 1 year at the Rural Health Centre (RHC) noncommunicable disease (NCD) clinic, 1. To determine the control status for hypertension and diabetes. 2. To assess the relationship between proxy behavior for collection of medications and the control status. Settings and Design: Rural Health Centre, Ramanathapuram, Puducherry, India; record-based retrospective observational study. Methods and Material: The study employed a universal sampling of 396 eligible persons with diabetes and hypertension who had been on medication for over a year at the RHC NCD clinic and had recorded blood pressure and glucose values within the last 4 months. Case sheets of these patients were retrieved from the Medical Registration Department, and data from the past 12 months were collected and analyzed to assess proxy behaviors and absenteeism. Statistical Analysis Used: Data were entered from the case sheets in Epicollect5 and analyzed using Stata v17. Results: Among hypertensive patients, 48.01% were aged 60 and above, with 55.63% being female. Fifty-six percent of hypertensive patients had their condition controlled. For diabetic patients, 40.88% were aged 45–59 years, with 59.75% being female. Only 18.24% of diabetic patients had their condition controlled. The multivariable analysis examined factors associated with the control status of hypertension and diabetes. Those aged 30–44 (aRR: 1.47, 95% CI: 1.01–2.15) and 45–59 (aRR: 1.37, 95% CI: 1.03–1.82) had a higher risk of uncontrolled hypertension compared to those aged 60 and above. Gender did not show significant associations with hypertension control status. Regarding attendance status, patients who had both proxy and missed visits (RR: 1.46, 95% CI: 1.02–2.07) had a higher risk of uncontrolled hypertension. There was also a significant association with patients having more than three proxies (aRR: 1.51, 95% CI: 1.10–2.17) exhibiting a higher risk of uncontrolled hypertension. Absenteeism status showed that those absent for 1–3 visits had a higher relative risk (RR: 1.37, 95% CI: 1.03–1.82) of uncontrolled hypertension compared to those with no absenteeism. Conclusion: Proxy behavior affects the control status of persons with hypertension and diabetes. A longitudinal study is warranted to assess the relationship between proxy visits and control status.

Mid to late Holocene Indian monsoon variability, aridification and civilization changes in the Deccan Plateau, India

Climate change has been a key driver throughout human history and has frequently been associated with the rise and fall of civilizations. Holocene settlement changes or population displacements were almost always preceded by changes in climate. A high-resolution sedimentary record from the western Bay of Bengal offers insights to centennial-scale mid- to late-Holocene Indian summer monsoon (ISM) variability and its role in the decline of chalcolithic human settlements on India's Deccan Plateau. Increased erosion in the Indian peninsula during the mid to late Holocene, due to aridification and agricultural expansion, is evidenced by higher sedimentation, more magnetic mineral content, coarser magnetic grain size, and increased sand content. The results from mineral magnetic and textural analyses reveal centennial-scale abrupt weak ISM during the Bond events in the core monsoon zone of India. The Deccan Chalcolithic civilizations flourished between ~4.0–3.0 ka BP owing to the favorable climatic conditions, but most of the settlements were deserted after ~3.0 ka BP. We argue that the abrupt weakening of ISM during Bond event 2 (~3.1–2.8 ka BP) caused this collapse of Deccan Chalcolithic. The results from this study together with the published records of number of settlements and summed radiocarbon dates suggest a climate-culture link in the Deccan Plateau. The weak ISM periods in this study are coherent with the records of total solar irradiance record and the percentage of hematite-stained grains from the North Atlantic and suggest solar control on these abrupt climatic events.

Clinical profile of lung cancer in Southern India with special reference to initial presentation and acceptance of treatment: A single-center study

Clinical profile of lung cancer in Southern India with special reference to initial presentation and acceptance of treatment: A single-center study

Reconstructed centennial precipitation-driven water storage anomalies in the Nile River Basin using RecNet and their suitability for studying ENSO and IOD impacts

While the Gravity Recovery And Climate Experiment (GRACE) and its Follow-On (GFO) missions have offered valuable observations for monitoring total water storage anomalies (TWSA), their short record constrains our ability to study the complete range and long-term variability of TWSA in the Nile River Basin (NRB). Previous studies reconstructing TWSA in this region either relied on specific hydrological models or did not consider spatial correlations among the TWSA grids. Here, we employ RecNet, a deep learning model capable of providing independent TWSA observations without relying on hydrological models while considering spatial correlations, to reconstruct precipitation-driven TWSA in the NRB from 1923 to 2022. The reconstructed data are validated by comparisons with the Global Land Data Assimilation System (GLDAS), the WaterGAP Global Hydrology Model (WGHM), the water balance budget, long-term runoff data, and GRACE-REC (i.e., a global reconstruction dataset freely available online). Subsequently, the suitability of the reconstructed data for studying El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) impacts within the NRB is assessed. Dividing the NRB into four sub-regions, i.e., the Lake Victoria Basin (LVB), the Bahr el Jebel and Bahr el Ghazal basins (BJBG), Ethiopian Highlands region (EH), and the Lower Nile River Basin (LNRB), it is shown that RecNet successfully reconstructs precipitation-driven TWSA over BJBG and EH, achieving correlation coefficient (CC), normalized root mean square error (NRMSE), and Nash–Sutcliffeefficiency (NSE) of 0.94/0.11/0.88 and 0.96/0.09/0.91 during the testing period, respectively. Additionally, RecNet’s reconstruction shows better agreement with GLDAS and WGHM than GRACE-REC, correlating well with runoff and the water balance budget in these regions. The relatively poor performance in the LVB and LNRB regions could be attributed to the substantial influence of Lake Victoria and the arid climate, respectively. Correlation analysis and wavelet coherence analysis identify significant coherence between ENSO/IOD and the reconstructed TWSA in BJBG and EH, with CC values of −0.68/0.34 and −0.82/0.56, respectively. This study provides centennial reconstructed TWSA data that could be useful in climate change/variability studies and water resource management within the NRB.

Effect of Regional Anthropogenic Aerosols on Tropical Cyclone Frequency of Occurrence

AbstractPrevious studies have highlighted the distinct impacts of anthropogenic aerosols from the Western and Eastern Hemispheres on past multi‐decadal changes in tropical cyclone frequency of occurrence (TCF). However, the detailed effect of subregional aerosol variations remained unclear. Using idealized simulations with a dynamical climate model, this study reveals that reduced aerosol emissions from Europe and the U.S. since 1980 may have equally contributed to increased TCF over the North Atlantic, with Europe playing a major role in the decreased TCF in the South Indian Ocean and the U.S. contributing to the decrease in TCF in the South Pacific. Additionally, increased aerosol emissions from India since 1980 may have played a major role in decreasing TCF over the western North Pacific compared to increased emissions from China. TCFs are projected to decrease for most global tropics toward the end of this century due to the dominant effect of increasing greenhouse gases.