Impact of consistent boundary layer mixing approaches between NAM and CMAQ

Discrepancies in grid structure, dynamics and physics packages in the offline coupled NWS/NCEP NAM meteorological model with the U.S. Environmental Protection Agency Community Multiscale Air Quality (CMAQ) model can give rise to inconsistencies. This study investigates the use of three vertical mixing schemes to drive chemistry tracers in the National Air Quality Forecast Capability (NAQFC). The three schemes evaluated in this study represent various degrees of coupling to improve the commonality in turbulence parameterization between the meteorological and chemistry models. The methods tested include: (1) using NAM predicted TKE-based planetary boundary height, h, as the prime parameter to derive CMAQ vertical diffusivity; (2) using the NAM mixed layer depth to determine h and then proceeding as in (1); and (3) using NAM predicted vertical diffusivity directly to parameterize turbulence mixing within CMAQ. A two week period with elevated surface O₃ concentrations during the summer 2006 has been selected to test these schemes in a sensitivity study. The study results are verified and evaluated using the EPA AIRNow monitoring network and other ozonesonde data. The third method is preferred a priori as it represents the tightest coupling option studied in this work for turbulent mixing processes between the meteorological and air quality models. It was found to accurately reproduce the upper bounds of turbulent mixing and provide the best agreement between predicted h and ozonesonde observed relative humidity profile inferred h for sites investigated in this study. However, this did not translate into the best agreement in surface O₃ concentrations. Overall verification results during the test period of two weeks in August 2006, did not show superiority of this method over the other 2 methods in all regions of the continental U.S. Further efforts in model improvement for the parameterizations of turbulent mixing and other surface O₃ forecast related processes are warranted.     

The impact of chemical lateral boundary conditions on CMAQ predictions of tropospheric ozone over the continental United States

A sensitivity study is performed to examine the impact of lateral boundary conditions (LBCs) on the NOAA-EPA operational Air Quality Forecast Guidance over continental USA. We examined six LBCS: the fixed profile LBC, three global LBCs, and two ozonesonde LBCs for summer 2006. The simulated results from these six runs are compared to IONS ozonesonde and surface ozone measurements from August 1 to 5, 2006. The choice of LBCs can affect the ozone prediction throughout the domain, and mainly influence the predictions in upper altitude or near inflow boundaries, such as the US west coast and the northern border. Statistical results shows that the use of global model predictions for LBCs could improve the correlation coefficients of surface ozone prediction over the US west coast, but could also increase the ozone mean bias in most regions of the domain depending on global models. In this study, the use of the MOZART (Model for Ozone And Related chemical Tracers) prediction for CMAQ (Community Multiscale Air Quality) LBC shows a better surface ozone prediction than that with fixed LBC, especially over the US west coast. The LBCs derived from ozonesonde measurements yielded better O₃ correlations in the upper troposphere.     

Effect of heavy metals (Hg and Zn) on the growth and phosphate solubilising activity in halophilic phosphobacteria isolated from Manakudi mangrove

The diversity of phosphobacteria in Manakudi mangrove ecosystem of Tamil Nadu was carried out in root and rhizosphere soil samples. The counts of phosphobacteria were found higher in root samples than in soil samples particularly in Hymenachene acutigluma. The abundance of phosphobacterial diversity in Manakudi mangrove showed high degree of positive correlation with the content of phosphate in rhizosphere soil of all the mangrove and associated plant species. Nine phosphobacterial species belonging to 7 genera were reported from Manakudi mangrove ecosystem. All the identified bacterial species are sensitive to both the heavy metals (mercury and zinc) in terms of growth and physiology even at lower concentrations. The content of protein and total sugars were increased by the higher concentrations of heavy metals whereas decreased trend was noticed in lower concentrations of heavy metals.     

Settling characteristics of nursery pig manure and nutrient estimation by the hydrometer method

The hydrometer method to measure manure specific gravity and subsequently relate it to manure nutrient contents was examined in this study. It was found that this method might be improved in estimation accuracy if only manure from a single growth stage of pigs was used (e.g., nursery pig manure used here). The total solids (TS) content of the test manure was well correlated with the total nitrogen (TN) and total phosphorus (TP) concentrations in the manure, with highly significant correlation coefficients of 0.9944 and 0.9873, respectively. Also observed were good linear correlations between the TN and TP contents and the manure specific gravity (correlation coefficients: 0.9836 and 0.9843, respectively). These correlations were much better than those reported by past researchers, in which lumped data for pigs at different growing stages were used. It may therefore be inferred that developing different linear equations for pigs at different ages should improve the accuracy in manure nutrient estimation using a hydrometer. Also, the error of using the hydrometer method to estimate manure TN and TP was found to increase, from +/- 10% to +/- 50%, with the decrease in TN (from 700 ppm to 100 ppm) and TP (from 130 ppm to 30 ppm) concentrations in the manure. The estimation errors for TN and TP may be larger than 50% if the total solids content is below 0.5%. In addition, the rapid settling of solids has long been considered characteristic of swine manure; however, in this study, the solids settling property appeared to be quite poor for nursery pig manure in that no conspicuous settling occurred after the manure was left statically for 5 hours. This information has not been reported elsewhere in the literature and may need further research to verify.     

A macroeconomic analysis of adaptation to climate change impacts on forests in India

We examine the potential for adaptation to climate change in Indian forests, and derive the macroeconomic implications of forest impacts and adaptation in India. The study is conducted by integrating results from the dynamic global vegetation model IBIS and the computable general equilibrium model GRACE-IN, which estimates macroeconomic implications for six zones of India. By comparing a reference scenario without climate change with a climate impact scenario based on the IPCC A2-scenario, we find major variations in the pattern of change across zones. Biomass stock increases in all zones but the Central zone. The increase in biomass growth is smaller, and declines in one more zone, South zone, despite higher stock. In the four zones with increases in biomass growth, harvest increases by only approximately 1/3 of the change in biomass growth. This is due to two market effects of increased biomass growth. One is that an increase in biomass growth encourages more harvest given other things being equal. The other is that more harvest leads to higher supply of timber, which lowers market prices. As a result, also the rent on forested land decreases. The lower prices and rent discourage more harvest even though they may induce higher demand, which increases the pressure on harvest. In a less perfect world than the model describes these two effects may contribute to an increase in the risk of deforestation because of higher biomass growth. Furthermore, higher harvest demands more labor and capital input in the forestry sector. Given total supply of labor and capital, this increases the cost of production in all the other sectors, although very little indeed. Forestry dependent communities with declining biomass growth may, however, experience local unemployment as a result.     

Mitigating Industrial Pollution Along the Atlantic Coast of Cameroon: An Overview of Government Efforts

Summary This paper presents an overview of the initiatives that have been formulated by the government of Cameroon to address the problem of industrial pollution. It also prescribes robust recommendations that could be employed to save the Atlantic coast of Cameroon from industrial pollutants. After the participation of Cameroon in the Earth Summit in Rio de Janeiro in 1992, the government took a significant step to overhaul its institutional framework, legal framework and policy framework vis-à-vis the regulation of industrial pollution. Under the auspices of the United Nation Industrial Development Organisation (UNIDO), the Gulf of Guinea Large Marine Ecosystem Project aimed at sustaining the health of the Atlantic coast of Cameroon by ensuring treatment of industrial wastes, oil spills, sewage and heavy metals was implemented (1995–1999). Based upon careful analysis, however, the paper argues that these efforts have had little or no discernable impacts and that industrial activities along the Atlantic coast of Cameroon are still a major threat to safety, health and the environment. With a considerable number of hurdles that still persist, sufficient environmental improvement in industrial pollution along the Atlantic coast of Cameroon is far-fetched. Nevertheless, the paper concludes that marked environmental improvement can be obtained if: (i) competent personnel are appointed in ministries that play an active role in mitigating industrial pollution (ii) research partnerships are forged with local universities (iii) industrial machinery and equipment are improved (iv) inter institutional conflicts are addressed (v) a more collaborative forum between stakeholders is established (vi) adequate monitoring is instituted. The provisions of this paper form the foundation of an ongoing research being conducted by the authors at Brandenburg University of Technology, Cottbus, Germany.