Prediction of precipitation associated with a western disturbance using a high-resolution regional model: role of parameterisation of physical processes

In this study a non-hydrostatic version of the PSU/NCAR mesoscale model is used to simulate an active western disturbance (WD) that affected the Indian region in January 1997. The role of the planetary boundary layer (PBL) and convection parameterisation schemes in the development of the WD is investigated. Analysis and predictions for some fields, including sea level pressure, geopotential height, temperature, horizontal wind and precipitation are examined. Some statistical scores are also calculated and compared. It is found that the performance of the Hong-Pan (as implemented in the NCAR MRF model) and Betts-Miller (or Grell) schemes as PBL and convection parameterisation schemes respectively are best compared to the other schemes used in this study

Monsoon rain chemistry and source apportionment using receptor modeling in and around National Capital Region (NCR) of Delhi, India

Studies on monsoon precipitation chemistry were carried out to understand the nature of rainwater and sources of pollution at eight different locations in and around the National Capital Region (NCR) of Delhi during southwest monsoon in the years 2003-2005. These sites were Bulandshahr (BUL), Garhmuktesar (GAR), Muradnagar (MUR), Sardhana (SAR), Panipat (PAN), Charkhi Dadri (CHA), Hodal (HOD) and Bahror (BAH). The rainwater samples, collected at these locations, were analyzed for major anions, cations and pH. The data were assessed for its quality. In general, the order of concentrations of major ions was observed to be: Ca 2+>SO 4 2->HCO 3 ->NH 4 +>Cl ->NO 3 ->Na +>Mg 2+>K +> F -. The average pH of rainwater at these stations was observed to be 6.39, ranging from 5.77 to 6.62, indicating alkaline nature. However, a few rain events, 31 at Panipat, 12 at Muradnagar and 29 at Sardhana, were observed to be acidic (pH<5.6). Acidity observed at Panipat and Muradnagar is attributed to industrial influence but at Sardhana to weak organic acids contributed by surrounding vegetation. No definite trends are found for most of the components at all the sites. However, concentrations of Cl - at Bulandshahr; NO 3 - at Muradnagar and Hodal; F - at Panipat and Bahror; Na + at Bulandshahr; K + at Bahror and Bulandshahr; Ca 2+ at Bulandshahr, Muradnagar, Charkhi Dadri and Sardhana; Mg 2+ at Panipat, Bahror, Bulandshahr, Hodal and Sardhana have increased from 2003 to 2005. For source identification, principal component analysis (PCA) was made, which showed that in general, at all the sites; suspended soil-dust and sea salts which are natural sources, were identified as the most dominating. Sources like agriculture including cattle, brick kilns and industries were reflected in third or fourth PC indicating moderate influence of anthropogenic activities in this region

A preliminary analysis of soil temperature at five different sites under land surface processes experiment in the Sabarmati rive basin

199-206An attempt has been made to study the thermal properties of soil at five different sites, namely, Khanda, Derol, Sanand, Arnej and Anand under land surface processes (LSP) experiment it the Sabarmati river basin, Gujarat, utilising the data collected during 13-17 Feb. 1997. Among these site Khanda and Arnej are of clay soil type, Derol and Anand with soil of loamy sand and Sanand is of clay loam type of soil. For all these sites thermal diffusivity has been calculated by three methods, namely, amplitude decay of diurnal wave (range method); time lag data (lag method) and damping depth concept. The values obtained by all these methods are in god agreement. Thermal diffusivity for clay soil is found to be of lesser values (0.287x10-6m2s-1 for Khanda and 0.304x10-6m2s-1 for Arnej) and for loamy sand and clay loam types it shows higher values (0.677x10-6m2s-1 at Derol, 0.591x10-6m2s-1 at Sanand and 0.508x10-6m2s-1 at Anand). Diurnal variation of soil temperature at each depth and soil heat flux (surface) are presented. Thermal conductivity has been calculated for all the sites. An attempt has also been made to predict soil temperature profile with time from the theoretical behaviour of thermal wave. Ground heat flux calculated by observed and theoretical profiles of temperature are also presented

Statistical evaluation of PM10 and distribution of PM1, PM2.5, and PM10 in ambient air due to extreme fireworks episodes (Deepawali festivals) in megacity Delhi

Temporal variation of PM 10 using 2-year data (January, 2007-December, 2008) of Delhi is presented. PM 10 varied from 42 to 200 μg m -3 over January to December, with an average 114. 1 ± 81. 1 μg m -3. They are comparable with the data collected by Central Pollution Control Board (National Agency which monitors data over the entire country in India) and are lower than National Ambient Air Quality (NAAQ) standard during monsoon, close to NAAQ during summer but higher in winter. Among CO, NO 2, SO 2, rainfall, temperature, and wind speed, PM 10 shows good correlation with CO. Also, PM 10, PM 2. 5, and PM 1 levels on Deepawali days when fireworks were displayed are presented. In these festive days, PM 10, PM 2. 5, and PM 1 levels were 723, 588, and 536 μg m -3 in 2007 and 501, 389, and 346 μg m -3 in 2008. PM 10, PM 2. 5, and PM 1 levels in 2008 were 1. 5 times lower than those in 2007 probably due to higher mixing height (446 m), temperature (23. 8°C), and winds (0. 36 ms -1). © 2011 Springer Science+Business Media B.V