Predicting Hydrological Drought: Relative Contributions of Soil Moisture and Snow Information to Seasonal Streamflow Prediction Skill

in this study we examine how knowledge of mid-winter snow accumulation and soil moisture conditions contribute to our ability to predict streamflow months in advance. A first "synthetic truth" analysis focuses on a series of numerical experiments with multiple sophisticated land surface models driven with a dataset of observations-based meteorological forcing spanning multiple decades and covering the continental United States. Snowpack information by itself obviously contributes to the skill attained in streamflow prediction, particularly in the mountainous west. The isolated contribution of soil moisture information, however, is found to be large and significant in many areas, particularly in the west but also in region surrounding the Great Lakes. The results are supported by a supplemental, observations-based analysis using (naturalized) March-July streamflow measurements covering much of the western U.S. Additional forecast experiments using start dates that span the year indicate a strong seasonality in the skill contributions; soil moisture information, for example, contributes to kill at much longer leads for forecasts issued in winter than for those issued in summer

The Impact of Organic Contamination on the Dynamic Equilibrium of Dissolve Oxygen in Selected Water Bodies in South East Sri Lanka

Domestic and other related waste disposals lead to degrade the rate of equilibrium ofdissolved oxygen (DO) in the water bodies. The aim of this study is to investigate thecontributions of the organic contamination throughout the measured parameters of dissolvedsulfide, chemical oxygen demand (COD), nutrient level and salinity in dynamic equilibriumof DO. The selected parameters were observed over a period of six month and thecorrelations were studied among them for randomly selected two water bodies (WB) withdifferent type of waste effluents. Results indicated that the measured DO has good negativecorrelation with COD (r2 > 0.8), dissolved sulfide and nutrient levels in the both stationsimplies a strong impact on the dynamic equilibrium of DO. Also, the measured DOdemonstrated poor negative correlations (r2 < 0.5) with salinity indicate salinity as a lessimportant parameter for the dynamic equilibrium of DO.The measured data were utilised in estimating the oxygen transfer efficiency, α and β values.Particularly, in Karaivahu (WB) and Allai (WB) exhibited low levels of partial pressuresimply higher level of α and lower β values. However, which were found to be in the range of8.67 – 16.88 and 0.99 – 1.02 respectively. The nutrient and COD values were observed in therange of 0.0 - 10.0 mg/L and 0 - 900 mg/L respectively. This concluded that the COD levelsignificantly contributes to the variation of DO throughout the surface active substance in thewater bodies.

The Effects of an Improved Dynamic Vegetation Phenology Representation in a Global Land Surface Model

Evapotranspiration (ET) is a major driver of the interaction between the land surface and the atmosphere through its component mechanisms, including plant transpiration (T) and soil evaporation. To accurately capture land-atmosphere interactions in global Earth System Models, it is thus critical that the underlying land surface models accurately model both the land hydrology as well as the dynamic response of vegetation to environmental drivers. In an effort to introduce a more realistic vegetation representation, the NASA Catchment land surface model, which is part of the Goddard Earth Observing System (GEOS), has previously been merged with the carbon and nitrogen physics modules of the Community Land Model version 4, resulting in the new Catchment-CN model. Catchment-CN has inherited the advanced treatment of land surface hydrology of Catchment, but is additionally able to dynamically model the response of vegetation to environmental drivers, in contrast to the fixed vegetation climatology that was prescribed in Catchment. Recently, the parameterization of Catchment-CN vegetation has been augmented to better account for variability of vegetation responses to external forcings within existing plant functional types, and vegetation parameters have been calibrated against Moderate Resolution Imaging Spectrometer observations of the fraction of absorbed photosynthetically radiation. These efforts have led to a significant reduction in the RMSE of modeled photosynthetic activity with respect to observations.This presentation investigates the effect of the improved vegetation representation on the partitioning of ET within Catchment-CN. Specifically, we compare global maps of the T:ET ratio across different temporal scales in (1) the original Catchment model, (2) the original Catchment-CN model, and (3) the augmented and calibrated Catchment-CN model. The modeled T and ET estimates are compared against a comprehensive set of ground observations from various field studies, as well as independent global T:ET estimates from different ET algorithms provided in the context of the Water Cycle Observation Multi-mission Strategy ? Evapotranspiration (WACMOS-ET) initiative

DEVELOPMENT OF AN ENVIRONMENT FRIENDLY METHOD TO REMOVE THE COLORED COMPONENTS FROM INDUSTURIAL WASTE WATER

Nowadays, synthetic dye context is a vital component in the textile and dyeing industries.The garr ient factories in the free trade zone that are discharging dyes and other colouredcornpounds into waterways pollute the environment. In this project, attempts were made todesign an environment friendly methodology to degrade Azo dyes by means of Eco--efficient techniques. Optimum conditions were evaluated for the redox-degradation of theAzo dyes and some of the dyes that are used in garment industry. The fidelity of theproposed mechanism was confirmed by the spectroscopic and GC analyses. As a reducingagent, metallic iron has fulfilled all the requirements that are prescribed for green chemicalconcepts.The results presented in this report clearly demonstrate that Anthroquinone-2-sulphonicacid is a powerful catalyst, capable of accelerating the reaction rate by orders ofmagnitude. The powdered form of charcoal amalgamated with metallic iron hasfacilitated as a better substrate to adsorb the dye component improving the contacts ofreactant molecules with the catalyst and dye molecules. The experimental results revealedthat pH 4 is the optimum condition for the redox degradation of the dye, which isconfirmed by electrochemical, and thermodynamic calculations. The elevation of thereaction temperature has accelerated the reaction by several orders of magnitude. Todemonstrate the applications in real world a continuous flow reduction apparatus wasdesigned and constructed.

Emission factors for selected PAHs and carbonyl compounds from locally available mosquito coils and joss stick brands

In recent years, numerous investigations have revealed that indoor air pollution has a subtle chemistrywhich produces a range of pollutants. Combustion sources (some of which can be eradicated fromindoors) have become the major contributor to the indoor air pollution and the pollutants emanatingfrom these sources can poses serious health threats. Two of the combustion sources which can beeliminated from indoor settings, burning mosquito coils and joss sticks, were investigated in this studywith the emphasis on the einissions of the carbonyl compounds and polycyclic aromatic hydrocarbons[PAHs].Both carbonyl compounds and PAHs are known health hazards which are ubiquitous in the indoorsdue to incomplete combustion of organic compounds as well as due to the off gassing from consumerproducts. Poor air circulations entrap the pollutants indoors elevating the exposure and hence thehealth risks. Seven mosquito coil brands (locally made) and eight joss stick brands (both locally andIndian made) were burned in a laboratory setting simulating the indoor conditions. All the smokeemanating from the combustion source was passed through a prototype sampler. The volatile carbonylcompounds were derivatized to non-volatile 2,4-dinitrophenyl hydrazones and PAHs were collectedseparately using methanol. The hydrazone derivatives of the carbonyl compounds and the PAHswere separated individually using reversed-phase HPLC and quantified using UV and fluorescencedetectors respectively.The average emission factors for mosquito coils were 266 ± 114 ug g' (formaldehyde), 94 ± 37 ug gI (acetaldehyde) and 67 ± 13 ug g' (acetone) compared to that of joss sticks 127 ±'18 ug g'(formaldehyde), 38 ± 11 ug g' (acetaldehyde) and 38 ± 11 ug s:' (acetone). The levels of acrolein,croton aldehyde and propanaldehyde were very low and they could not be quantified with significantaccuracy and precision.The emission factors for naphthalene, acenapthene, acenapthylene, fluorine, phenanthrene, anthracene,fluoranthene, pyrene, benzo[ a]anthracene, chrysene, benzo[b ]fluoranthene, benzo[k ]fluoranthene andbenzo[a]pyrene were 6.33 ± 1.00,9.45 ± 1.04, 2.44 ± 0.47,6.54 ± 0.54,9.07 ± 0.55,3.96 ± 0.98,4.63± 0.44, 0.64 ± 0.17, 1.52 ± 0.42,2.67 ±0.66, 0.25 ± 0.08, 0.21 ± 0.05 and 0.17 ± 0.15 ug g' respectivelyfor mosquito coils and the emission factors of joss sticks for the same compounds were 5.33 ± 0.94,7.80 ± 0.95, 2.14 ± 1.14,4.25 ± 1.04,4.79 ± 0.66,3.53 ± 0.42,5.04 ± 0.99, 0.44 ± 0.12, 1.14 ± 0.17,1.63 ± 0.63, 0.1 R :: 0.04, 0.23 ± 0.15 and 0.15 ±.06 /lg g-I respectively.In general, Indian joss stick brands emitted more PAHs and carbonyl compounds compared to thelocal brands. This research is an attempt to glance at the exposures which can be prevented throughsimple measures such as control Iing the indoor combustions.

CONSTRUCTION OF A LOW COST AIR SAMPLER AND IT'S APPLICATION IN SAMPLING VOLATILE CARBONYL COMPOUNDS

lntcrcxt is expanding in measuring. concentrations of volatile organic compounds inbuildings since it is rccogniscd that many peoples' exposure to these compounds occur inthe indoor environment. However. such data are not available in Sri Lanka primarily dueto lack 01"proper equipment for quantitation and their high maintenance cost. This paperdcxcribcx the construction of a low cost air sampler (Rs. 40()/=) using commonly availablematerials.The air sampler contains a muffler fan to pull .unhient air though a filrcrts) and/or a bed ofsorhcnt material. which are housed in a variable length pye tube. Battery poweredmuffler fan and lightweight are two of the convenient features of this air sampler thatminimisc operational and transportation difficulties to the user.Vularilc carbonyl compounds such as formaldehyde acetaldehyde and acetone arecommonly found in indoors ambient air due to the combustion sources and emissions fromsvnthcric household products. Since formaldehyde is a known carcinogen andacetaldehyde is a suspected carcinogen compound. they were selected as the modelcompounds for the evaluation of constructed sampler. A filter paper spiked with 2. 4-dinitrophcnylhydruzcnc is used to collect the airborne carbonyl compounds at a flow rate ofI.X Cill'/SCC. Filters were sonicated in methanol and extracts were separated using a C,xcolumn for qu.uuitation at lSO mm wavelength. Quanutaiion limits estimates thats.unpling of I () dm ' ambient air enables minimum quantitauon of O.S formaldehyde. 1.0acetaldehyde and 1.2 acetone accurately. The paper also reports quantified levels ofairborne carbonyls from different indoor environments.

INVESTIGATION OF SULFUR COMPOUNDS IN SELECTED STAGNANT WATER BODIES

Sulfur compounds, primarily in the form of sulfides (S2.), sulfites (50)'") andsulfates (50t) have been neglected but has a strong effect upon water quality.The dark colour sediments and strong unpleasant ordours often indicate the 52.contamination in aquatic bodies. To the best of our knowledge, no attempt hasbeen made to investigate these compounds and to asses their contribution to thedegradation of water quality. Both the bacteria and dissolved oxygen (DO) areplaying leading roles in determining the fate of 5 containing compounds inaquatic systems.In this investigation it was intended to study the possible relationships betweensulfur species and DO. Four urban stagnant water bodies effected by impropersewage disposal, industrial waste, wet and dry deposition of atmospheric 50/'were investigated along with a prawn farm and two coconut husk soaking pitsinherited with S compounds. These water bodies indicated the emission ofvolatile 5 compounds. These water bodies indicated the emission of volatile 5compounds From their characteristic rotten egg smell.Under this study 52., SO)·2 and 50t levels were monitored along with DO, pHand temperature to investigate the possible correlation method introduced byPawlak and Pawlak (1999) was employed in determination of 52. levels while allother parameters were measured by employing standard methods.Based on the results obtained, only S2. shows a significant correlation with DOunder ambient conditions. Finally, measured dissolved 52. levels were utilized todetermine the possible H25 emission levels. Calculations have shown that each ofthe water body is emitting gaseous H25 and in most cases, emission levels aregreater than the ordour thresholds accounting for the unpleasant smell near thesestagnant water bodies.*Correspondence author

Mechanisms Associated with Daytime and Nighttime Heat Waves over the United States

Heat waves are extreme climate events that have the potential to cause immense stress on human health, agriculture and energy systems, so understanding the processes leading to their onset is crucial. There is no single accepted definition for heat waves, but they are generally described as a sustained amount of time where temperature exceeds a local threshold. Multiple different temperature variables are potentially relevant, as high values of daily maximum (T(max)) and minimum (T(min)) temperatures can both be detrimental to human health. Previous studies have concluded that the frequency of global heat waves has increased over recent decades, with greater increases in T(min)- than T(max)-heat waves in several regions. In this study, we focus explicitly on the different mechanisms associated with heatwaves manifest during daytime versus nighttime hours over the United States. Heat waves are examined using the National Aeronautics and Space Administration (NASA) Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2). A daytime (nighttime) heat wave is defined as average daytime (nighttime) temperature exceeding its calendar day 90th percentile for at least 3 days. Over 1980-2018, the number of heat wave days per summer has increased over much of the United States. Trends are stronger for nighttime versus daytime heat wave frequency over the Northeast, Midwest and Southwest United States. Local and remote processes linked with daytime and nighttime heat waves are identified through composite analysis of clouds, precipitation, soil moisture, and fluxes of heat and moisture. Finally, we characterize the large-scale atmospheric circulation associated with daytime and nighttime heat waves over different regions of the United States

Toxic Volatile Organic Compounds in Environmental Tobacco Smoke:Emission Factors for Modeling Exposures of California Populations

The primary objective of this study was to measure emission factors for selected toxic air in environmental tobacco smoke (ETS) using a room-sized environmental chamber. The emissions of 23 volatile organic compounds (VOCs), including 1,3-butadiene, three aldehydes and two vapor-phase N-nitrosarnines were determined for six commercial brands of cigarettes and reference cigarette 1R4F. The commercial brands were selected to represent 62.5% of the cigarettes smoked in California. For each brand, three cigarettes were machine smoked in the chamber. The experiments were conducted over four hours to investigate the effects of aging. Emission factors of the target compounds were also determined for sidestream smoke (SS). For almost all target compounds, the ETS emission factors were significantly higher than the corresponding SS values probably due to less favorable combustion conditions and wall losses in the SS apparatus. Where valid comparisons could be made, the ETS emission factors were generally in good agreement with the literature. Therefore, the ETS emission factors, rather than the SS values, are recommended for use in models to estimate population exposures from this source. The variabilities in the emission factors (pgkigarette) of the selected toxic air contaminants among brands, expressed as coefficients of variation, were 16 to 29%. Therefore, emissions among brands were generally similar. Differences among brands were related to the smoked lengths of the cigarettes and the masses of consumed tobacco. Mentholation and whether a cigarette was classified as light or regular did not significantly affect emissions. Aging was determined not to be a significant factor for the target compounds. There were, however, deposition losses of the less volatile compounds to chamber surfaces

Improving Water Level and Soil Moisture Over Peatlands in a Global Land Modeling System

New model structure for peatlands results in improved skill metrics (without any parameter calibration) Simulated surface soil moisture strongly affected by new model, but reliable soil moisture data lacking for validation