Kathmandu Valley is one of the largest and most polluted metropolitan regions in Himalayan foothills. Rapidly expanding urban sprawl a growing fleet vehicles, industrial facilities such as brick factories across valley have led to conditions where ambient concentrations key gaseous air pollutants are expected exceed Nepal's National Ambient Air Quality Standards (NAAQS) World Health Organization (WHO) guidelines. In order understand spatial variation trace gases Valley, passive samples SO2,...

Air pollution transport in the Kathmandu valley/basin has been investigated by numerical simulation of local flows and observation NO2 SO2. The was performed at 22 sites with passive samplers from February to April 2001, fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) utilized for flow simulation. calculation reproduced reasonably well surface wind temperature Tribhuvan International Airport (TIA) as vertical profile taken center valley sodar observation. showed...

Air pollution characteristics over the Kathmandu Valley in wintertime were numerically investigated by using a comprehensive transport–chemistry–deposition model of air pollutants together with fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). In Kathmandu, Nepal, it is known that double-layered local flows, is, southwesterly and northwesterly winds, formed as combined valley wind plain-to-plateau wind, develop every day afternoon. this study, effect flows on has...

Abstract Meteorological effects on wintertime air pollution in the Kathmandu Valley were investigated using SOnic Detection and Ranging soundings, Automatic Weather Station measurements, numerical simulation Research Forecasting data, Chemical Transport Modeling during February 2013. A surrogate for black carbon was used transport order to better understand of local meteorological factors pollution. In simulation, emission strength assumed temporally constant spatially uniform over floor....

Abstract Nepal has been the location of a series fatal aircraft accidents, raising serious concerns about civil aviation security and safety passengers. However, significant studies on weather patterns associated with airports air routes Himalayan complex terrain their implications for activities are yet to be carried out. The present study numerically reconstructs prevailing conditions puts forward some possible causes behind most recent accident in foothills western Himalaya at 0730 UTC...

Jomsom Airport of Nepal is considered to be one the world’s most extreme airports. The frequency aircraft crashing along Kali Gandaki River Valley and over very high. Pre-monsoon time local flow characteristics has been studied understand meteorological hazards for aviation activities valley with application WRF Modeling System initialized NCEP meteorological, USGS 24 categories land use, 30 second terrain data. Four days long simulation was carried out period 15 May 0000 UTC 19 UTC, 2012...

Kathmandu valley has seen visible transformations in its intrinsic climate recent decades. The atmosphere of the become increasingly uncomfortable, unhealthy and more susceptible to, so far, unanticipated viral other diseases. lack spatial distribution temporal variation potential climatic parameters as well future scenarios have given rise to serious uncertainties with respect change development adaptation strategies for sustainable beyond. An accurate assessment gridded documentation...

The airplane of Nepal Army in-route to Kathmandu Airport from Nepalgunj lost its communication with the air traffic control room sky Thada Arghakhachi District. plane was found breath taking crashing over Bowang high mountain area Baglung weather pattern has been numerically reconstructed application Weather Research and Forecasting (WRF) model initialized NCEP FNL meteorological USGS land use terrain elevation data examined effect prevailing pattern. show that atmosphere associated areas...

Abstract Safe flights over the Tribhuvan International Airport (TIA), Kathmandu, Nepal, remain a considerable challenge. Since airport opened, there have been 13 aircraft accidents during landings and takeoffs that claimed 392 lives. A detailed understanding dependable forecast of atmospheric conditions may develop complex terrain midhills central Nepal Himalaya are yet to be achieved. The present study discusses near-surface possibly associated with most recent fatal crash at TIA on 12...

The early monsoon time atmospheric transport processes over the Hetauda valley, closest low-land that accommodates third largest industrial district of Nepal, has been studied with application Weather Research and Forecasting (WRF) Modeling System initialized NCEP meteorological USGS terrain elevation land-use data. study reveals mixing layer valley may evolve as much 3 km above surface during afternoon time. near atmosphere appears very weakly stratified even in morning indicating...

Meteorological effects on wintertime air pollution in the Kathmandu Valley were investigated using SOnic Detection and Ranging soundings, Automatic Weather Station measurements, numerical simulation Research Forecasting data, Chemical Transport Modeling during February 2013. A surrogate for black carbon was used transport order to better understand of local meteorological factors pollution. In simulation, emission strength assumed temporally constant spatially uniform over floor. The results...

<p>As part of the ongoing research activities at National Atmospheric Resource and Environmental Research Laboratory (NARERL) to realize high spatial temporal resolution weather forecasts for Nepal, Weather Forecasting (WRF) modeling system performance with Center Protection (NCEP) Medium Range Forecast (NCMRWF) initialization global meteorological data sets effect surface observation assimilation have been examined. The study shows that WRF reasonably well predicts diurnal variation...

Available with full text.The Himalayan Physics Vol. 5, No. Nov. 2014Page: 59-68

The early monsoon time boundary layer characteristics prevailing over Aindanda low-mountain pass of Kathmandu valley has been continuously monitored for the period 11 to 24 June 2013. study reveals that channels regional air masses from western neighboring up into as westerly/ northwesterly winds during daytime whereas it drains mass out night-time. speed westerly/northwesterly wind often exceeds 6.5 ms-1 late afternoon. Nighttime mixing height (MLH) was highly fluctuating with an average...

On the evening of 31 March 2019, Parsa and Bara Districts in central Nepal were severely hit by a wind storm which was first documented tornadic incidence Nepal.In this paper, we investigate background tornado formation via numerical simulations with WRF-ARW model. The results show that: (1) flow situation favorable to generation mesocyclones formed combination local plain-to-mountain winds consisting warm humid southwesterly lower atmosphere synoptic northwesterly aloft over southern...

Air pollution transport in Kathmandu valley has been investigated reference to the observed concentration distribution of NO2 and SO2 numerical simulation local flow fields. The spatial distributions were measured two ways: one is a 3-weeks average during 18 February 11 March 1-day on 12 April 2001 at identical sites with passive samplers. Using PSU-NCAR Mesoscale Model MM5, initializing ECMWF meteorological fields, conditions over simulated.The reasonably reproduced characteristic late...

The atmospheric conditions leading to the hailstorm over Mt. Masina Lekh (~1800 m) and its immediate surroundings has been numerically simulated by implementing Advance Weather Research Forecasting (WRF) modeling system. distribution of cloud water-mixing ratio numerical sounding profiles strongly suggest massive scale in around Lekh. atmosphere area was fully saturated with cloud-water mixing exceeding 1.42 g kg-1and temperature at top (~800 hPa) remained close freezing decreased quickly...

Atmospheric processes over the Himalayan complex terrain are yet to be studied extensively. Only a few significant researches reported from this region and Far-Western Region (FWR) of Nepal still remains untouched. Thus, present study was conceived understand meteorological flow characteristics thermal environment associated areas during late wintertime with application state-of-the-art-of Weather Research Forecasting (WRF) Modeling System. The revealed that northern mountainous developed...

<p class="Default">Wind power potential prevailing over the world’s deepest river gorge, Kali Gandaki River Valley, located in western trans-Himalaya region of Nepal, has been assessed and mapped at 1 km × horizontal grid resolution with application Weather Research Forecasting (WRF) modeling system. The wind maps cover 70 area, which encloses very first failed project country Jomsom Airport center. simulated characteristics compare well available observed characteristic. appears to...

The knowledge and an accurate representation of the spatial distribution groundwater depth area are very important to realize sustainable use resource, protection ecosystem for development adaptation policies in changing climate. present study has, thus, developed a map southern low-lands Sunsari District at horizontal grid resolution 3 km × km. depths were surveyed predefined 82 numbers geo-referenced points scattered over region during post monsoon season year 2019. Referencing sampled...