Hydrologic model forcing over the Himalaya

In the Himalayas –the mountain range in Asia, there is a high demand for hydro-meteorological datasets for the water resource management. Hydro-meteorological observations is minimal because of the adverse geographical conditions and this represent a problem. Remote sensing and climate models offer a global perspective on many atmospheric climatic variables. However, low spatial resolution and inability to measure some atmospheric properties, such as Aerosol Optical Depth (AOD) over the brighter surface limits their ability to reflect the effects on hydrologic systems. During this PhD study, the candidate and team developed an empirical based model to estimate the AOD for the region. The model helps to understand aerosol and its impacts on the Himalayan hydrology. Similarly, we evaluated a regional climate model and reanalysed datasets for hydrological simulations. We fond the highest-fidelity of discharge simulation when using observation combined Watch Forcing Dataset ERA Interim (WFDEI) datasets. Our results show the successful application of global forcing datasets over the Himalayas. Finally, we demonstrated that catchment discretization has a significant impact on hydrologic simulation results. Triangular Irregular Network (TIN) based catchment discretization gives the highest model performance. Hence the selection of models with an appropriate complexity and accurate forcing data are the most required to achieve reliable hydrologic simulation over the entire Himalayan regio

The influence of different mulching materials on Tomato's vegetative, reproductive, and yield in Dhankuta, Nepal

Dhankuta is considered a high-tomato production area in Nepal. The types of mulch recommended by government bodies and research stations are based on blanket recommendations. Research is carried out to identify the effect of different mulching materials like rice husk and silver on black plastic, straw, sawdust, and control on performance of tomatoes. It was investigated in a one-factorial randomized complete block design (RCBD) with 4 replications and 5 treatments in a farmer's field, Patlekhola, Dhankuta. This study focused on plant growth and yield characteristics. The data were analyzed with R stat software at a 5% level of significance. Mulch application did not affect the number of leaves, stem diameter at 30, 45, or 60 days after planting, height to first truss initiation or reproductive characteristics. Mulch treatments had an effect on plant height and the number of leaves between two trusses at 60 DAT, fruit diameter, number of fruits per plant, and total fruit yield (Mt/ha) when compared to the control. The result revealed that a plot mulched with rice husk generated the most fruits per plant around 20 and the highest fruit output (45.69 Mt/ha) with a 5.46 cm fruit diameter. This study will provide the farmer with a cost-effective selection of mulching practices and commercial cultivation of tomatoes in the upcoming days. Highlight: • Mulching had a considerable impact on the growth and yields of tomatoes. • The selection of mulching material is economic Point of decision. • The efficiency of mulched might have a different result on Different Farm. • Rice husk mulching produced the maximum tomato productivity. • The highest net return from rice husk is (1261240.5a) and the B:C ratio is (3.22a)

Aerosol Optical Depth Over the Nepalese Cryosphere Derived From an Empirical Model

In the Himalayan region, aerosols received much attention because they affect the regional as well as local climate. Aerosol Optical Depth (AOD) observation from satellite are limited in the Himalayan region mainly due to high surface reflectance. To overcome this limitation, we have conducted a multivariate regression analysis to predict the AOD over the cryospheric portion of Nepalese Himalaya. Prediction using three meteorological variables from ERA-Interim: relative humidity, wind velocity components (U10 and V10) were taken into account for model development as independent variables, while the longest time series AOD observation at Pokhara station is used as dependent variable. Model coefficients were found significant at 95 percent level with 0.53 coefficients of determination for daily values. Correlation coefficients between model output and AERONET observations were found to be 0.68, 0.73, 0.75, 0.83, and 0.82 at Lumbini, Kathmandu Bode (KTM-BO), Kathmandu University (KTM-UN), Jomson, and Pyramid laboratory/observatory (EVK2CNR) AERONET stations, respectively. Model overestimate AOD at Jomsom, and EVK2CNR AERONET stations while slightly underestimates AOD in Lumbini, KTM-UN, and KTM-BO AERONET station, respectively. Both model output and MODIS observation showed that the highest AOD over Nepal is observed during winter and pre-monsoon season. While lowest AOD is observed during monsoon, and post-monsoon season. The result of this research supports that the use of linear regression model yields good estimation for daily average AOD in Nepal. The model that we have presented could possibly be used in other mountain regions for climate research

An unusual case of bilateral pulmonary embolism in a patient on dual venous thromboprophylaxis, secondary to heparin induced thrombocytopenia

Heparin Induced thrombocytopenia (HIT) is a rare, immune-mediated complication of heparin, associated with both thrombocytopenia and paradoxical thrombotic events. Initial diagnosis is made clinically when platelet count falls by 30% to  50% decrease from baseline count in association with heparin therapy. Thromboembolic complications are seen in 50% of the cases. We present a case of acute pulmonary embolism (aPE) in a 65 year old male secondary to HIT while on unfractionated heparin for venous thromboprophylaxis. He was admitted to the hospital for severe acute exacerbation of asthma and was on heparin and venodyne boots for venous thrombo-prophylaxis. His chief presenting complaints improved until day 13, when he had severe pleuritic chest pain with worsening of shortness of breath and was desaturating while breathing ambient air. Computed tomography (CT) of the chest with intravenous contrast revealed aPE involving bilateral upper lobe segmental pulmonary arteries. Given the pattern and timing of thrombocytopenia prior to onset of his symptoms and acute thromboembolism, diagnosis of HIT was made which was later supported by positive platelet factor- ELISA and serotonin release assay (SRA) laboratory testing. Heparin and heparin-related products were promptly discontinued and argatroban was started. Later platelet count increased over 150 × 103/μL and argatroban was switched to warfarin prior to discharge. As heparin is extensively used, all physicians are required to be attentive of this life threatening complication. Discontinuing heparin while substituting with an alternative anticoagulant such as argatroban may become a life-saving strategy in such a case

Impact of Catchment Discretization and Imputed Radiation on Model Response: A Case Study from Central Himalayan Catchment

Distributed and semi-distributed hydrological modeling approaches commonly involve the discretization of a catchment into several modeling elements. Although some modeling studies were conducted using triangulated irregular networks (TINs) previously, little attention has been given to assess the impact of TINs as compared to the standard catchment discretization techniques. Here, we examine how different catchment discretization approaches and radiation forcings influence hydrological simulation results. Three catchment discretization methods, i.e., elevation zones (Hypsograph) (HYP), regular square grid (SqGrid), and TIN, were evaluated in a highly steep and glacierized Marsyangdi-2 river catchment, central Himalaya, Nepal. To evaluate the impact of radiation on model response, shortwave radiation was converted using two approaches: one with the measured solar radiation assuming a horizontal surface and another with a translation to slopes. The results indicate that the catchment discretization has a great impact on simulation results. Evaluation of the simulated streamflow value using Nash–Sutcliffe efficiency (NSE) and log-transformed Nash–Sutcliffe efficiency (LnNSE) shows that highest model performance was obtained when using TIN followed by HYP (during the high flow condition) and SqGrid (during the low flow condition). Similar order of precedence in relative model performance was obtained both during the calibration and validation periods. Snow simulated from the TIN-based discretized models was validated with Moderate Resolution Imaging Spectroradiometer (MODIS) snow products. Critical Success Indexes (CSI) between TIN-based discretized model snow simulation and MODIS snow were found satisfactory. Bias in catchment average snow cover area from the models with and without using imputed radiation is less than two percent, but implementation of imputed radiation into the Statkraft Hydrological Forecasting Toolbox (Shyft) gives better CSI with MODIS snow

Evaluation of global forcing datasets for hydropower inflow simulation in Nepal

Abstract Discharge over the Narayani river catchment of Nepal was simulated using Statkraft's Hydrologic Forecasting Toolbox (Shyft) forced with observations and three global forcing datasets: (i) ERA-Interim (ERA-I), (ii) Water and Global Change (WATCH) Forcing Data ERA-I (WFDEI), and (iii) Coordinated Regional Climate Downscaling Experiment with the contributing institute Rossy Centre, Swedish Meteorological and Hydrological Institute (CORDEX-SMHI). Not only does this provide an opportunity to evaluate discharge variability and uncertainty resulting from different forcing data but also it demonstrates the capability and potential of using these global datasets in data-sparse regions. The fidelity of discharge simulation is the greatest when using observations combined with the WFDEI forcing dataset (hybrid datasets). These results demonstrate the successful application of global forcing datasets for regional catchment-scale modeling in remote regions. The results were also promising to provide insight of the interannual variability in discharge. This study showed that while large biases in precipitation can be reduced by applying a precipitation correction factor (p_corr_factor), the best result is obtained using bias-corrected forcing data as input, i.e. the WFDEI outperformed other forcing datasets. Accordingly, the WFDEI forcing dataset holds great potential for improving our understanding of the hydrology of data-sparse Himalayan regions and providing the potential for prediction. The use of CORDEX-SMHI- and ERA-I-derived data requires further validation and bias correction, particularly over the high mountain regions

Coexistence of cerebral venous thrombosis and dural arteriovenous fistula in an adolescent: A case report

Key Clinical Message Clinicians should consider central venous thrombosis (CVT) as a differential diagnosis in young adolescents with persistent headaches. It is essential to assess for concurrent CVT and dural arteriovenous fistula (DAVF), particularly in those with a history of CVT. Abstract Cerebral venous thrombosis (CVT) and dural arteriovenous fistula (DAVF) are uncommon vascular disorders with diverse clinical presentations. The coexistence of CVT and DAVF is a rare but important association that may impact the management and prognosis of affected patients. Prothrombotic conditions generally ranging from acquired to genetic, oral contraceptives, malignancy, puerperium, infection, and head injury are the common risk factors for cerebral venous thrombosis. Here, we present a case of 18 years males who developed recurrent cerebral thrombosis on the background of the presence of an arteriovenous fistula

Preliminary results of mass-balance observations of Yala Glacier and analysis of temperature and precipitation gradients in Langtang Valley, Nepal

Monitoring the glacier mass balance of summer-accumulation-type Himalayan glaciers is critical to not only assess the impact of climate change on the volume of such glaciers but also predict the downstream water availability and the global sea-level change in future. To better understand the change in meteorological parameters related to glacier mass balance and runoff in a glacierized basin and to assess the highly heterogeneous glacier responses to climate change in the Nepal Himalaya and nearby ranges, the Cryosphere Monitoring Project (CMP) carries out meteorological observations in Langtang Valley and mass-balance measurements on Yala Glacier, a debris-free glacier in the same valley. A negative annual mass balance of -0.89mw.e. and the rising equilibrium-line altitude of Yala Glacier indicate a continuation of a secular trend toward more negative mass balances. Lower temperature lapse rate during the monsoon, the effect of convective precipitation associated with mesoscale thermal circulation in the local precipitation and the occurrence of distinct diurnal cycles of temperature and precipitation at different stations in the valley are other conclusions of this comprehensive scientific study initiated by CMP which aims to yield multi-year glaciological, hydrological and meteorological observations in the glacierized Langtang River basin