Amit Misra

Study of MPLNET-Derived Aerosol Climatology over Kanpur, India, and Validation of CALIPSO Level 2 Version 3 Backscatter and Extinction Products

AbstractThe level 2 aerosol backscatter and extinction profiles from the NASA Micropulse Lidar Network (MPLNET) at Kanpur, India, have been studied from May 2009 to September 2010. Monthly averaged extinction profiles from MPLNET shows high extinction values near the surface during October–March. Higher extinction values at altitudes of 2–4 km are observed from April to June, a period marked by frequent dust episodes. Version 3 level 2 Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) aerosol profile products have been compared with corresponding data from MPLNET over Kanpur for the above-mentioned period. Out of the available backscatter profiles, the16 profiles used in this study have time differences less than 3 h and distances less than 130 km. Among these profiles, four cases show good comparison above 400 m with R2 greater than 0.7. Comparison with AERONET data shows that the aerosol type is properly identified by the CALIOP algorithm. Cloud contamination is a possible source of error in the...

Latitudinal Variation of Aerosol Properties from Indo-Gangetic Plain to Central Himalayan Foothills During TIGERZ Campaign

As part of TIGERZ campaign, latitudinal variation of aerosol optical properties was analyzed over Indo-Gangetic Plains (IGP) to central Himalayas during premonsoon of 2008 and 2009. Measurements of aerosol optical depth (AOD) were performed using Aerosol Robotic Network Sun photometer at four sites with different aerosol environments. The AOD increases from Nainital located in central Himalayas to Kanpur located in IGP region. Further, aerosol size varies spatially with dominance of coarse-mode aerosols at Kanpur compared to fine-mode aerosols dominated at Nainital. Spectral variation of single-scattering albedo suggests that during premonsoon, dust is the dominant species in the IGP with exception of Pantnagar, where absorbing aerosols are dominant. The optical properties of aerosols are calculated, and shortwave clear-sky aerosol radiative forcing (ARF) is estimated. An insignificant difference is found in columnar ARF and columnar heating rate (HR) when vertical profiles of aerosols are included in radiative transfer models. Over Nainital, average ARF is estimated to be −7.61, −45.75, and 38.14 W m−2 at top of atmosphere (TOA), surface (SUR), and in the atmosphere (ATM), respectively. Average ARF is less negative at Kanpur compared to Pantnagar and Bareilly with values −17.63, −73.06, and 55.43 W m−2 at TOA, SUR, and ATM, respectively. ARF shows positive gradient from the highlands to the IGP sites; larger TOA and SUR cooling were observed at the three sites compared to the highland site. This translates into large columnar HR with estimated average values as 1.07, 1.41, 1.58, and 1.56 K d−1 for Nainital, Pantnagar, Bareilly, and Kanpur, respectively.

Automatic Generation of Digital System Schematic Diagrams

This paper presents a rigorours approach to automatic generation of schematic diagrams for digital systems described as networks of modules. This is very useful in comprehensive CAD environment. The approach is based on identification of some guidelines which are traditionally followed in mannual drawing of schematic diagrams. Theses guidelines are transformed into quantitative objectives. In view of the complex interrelationship between these objectives, the schematic design process is broken into a long sequence of steps. An attempt is made to give rigorous formulation for each step, along with efficient solutions, making suitable approximations where necessary. An illustrative diagram generated using these algorithms is included showing that the results compare well with hand drawn diagrams.

ACTIVE REDUNDANCY ALLOCATIONS IN SERIES SYSTEMS

The performance of a system can often be improved by introducing some kind ofredundancy into the system. The problem of optimally allocating redundant sparesto the components of a system has been vastly studied in the literature (see Boland,El-Neweihi,andProschan[3],LiandHu[8],Misra,Dhariyal,andGupta[9],Romera,Valdes, and Zequeira [11], Shaked and Shanthikumar [13], Singh and Misra [15], andValdes and Zequeira [17] and references cited therein).Two commonly used types of redundancy are the active redundancy and thestandby redundancy. In active redundancy, available spares are attached in parallel tocomponents of the system. In standby redundancy, spares are attached to componentsof the system in a manner that a spare starts functioning only after the failure of thecomponenttowhichitisattached.Twodifferentallocationsofsparescanbecomparedthrough stochastic orders between the lifetimes of corresponding systems. We recallsome of the definitions of stochastic orders relevant to the context of the article.Let

Reductions in indoor black carbon concentrations from improved biomass stoves in rural India.

Deployment of improved biomass burning cookstoves is recognized as a black carbon (BC) mitigation measure that has the potential to achieve health benefits and climate cobenefits. Yet, few field based studies document BC concentration reductions (and resulting human exposure) resulting from improved stove usage. In this paper, data are presented from 277 real-world cooking sessions collected during two field studies to document the impacts on indoor BC concentrations inside village kitchens as a result of switching from traditional stoves to improved forced draft (FD) stoves. Data collection utilized new low-cost cellphone methods to monitor BC, cooking duration, and fuel consumption. A cross sectional study recorded a reduction of 36% in BC during cooking sessions. An independent paired sample study demonstrated a statistically significant reduction of 40% in 24 h BC concentrations when traditional stoves were replaced with FD stoves. Reductions observed in these field studies differ from emission factor reductions (up to 99%) observed under controlled conditions in laboratory studies. Other nonstove sources (e.g., kerosene lamps, ambient concentrations) likely offset the reductions. Health exposure studies should utilize reductions determined by field measurements inside village kitchens, in conjunction with laboratory data, to assess the health impacts of new cooking technologies.

Global Sources of Fine Particulate Matter: Interpretation of PM2.5 Chemical Composition Observed by SPARTAN using a Global Chemical Transport Model

Exposure to ambient fine particulate matter (PM2.5) is a leading risk factor for the global burden of disease. However, uncertainty remains about PM2.5 sources. We use a global chemical transport model (GEOS-Chem) simulation for 2014, constrained by satellite-based estimates of PM2.5 to interpret globally dispersed PM2.5 mass and composition measurements from the ground-based surface particulate matter network (SPARTAN). Measured site mean PM2.5 composition varies substantially for secondary inorganic aerosols (2.4-19.7 μg/m3), mineral dust (1.9-14.7 μg/m3), residual/organic matter (2.1-40.2 μg/m3), and black carbon (1.0-7.3 μg/m3). Interpretation of these measurements with the GEOS-Chem model yields insight into sources affecting each site. Globally, combustion sectors such as residential energy use (7.9 μg/m3), industry (6.5 μg/m3), and power generation (5.6 μg/m3) are leading sources of outdoor global population-weighted PM2.5 concentrations. Global population-weighted organic mass is driven by the residential energy sector (64%) whereas population-weighted secondary inorganic concentrations arise primarily from industry (33%) and power generation (32%). Simulation-measurement biases for ammonium nitrate and dust identify uncertainty in agricultural and crustal sources. Interpretation of initial PM2.5 mass and composition measurements from SPARTAN with the GEOS-Chem model constrained by satellite-based PM2.5 provides insight into sources and processes that influence the global spatial variation in PM2.5 composition.