UV-B Robertson-Berger meter characterization and field calibration

The New Zealand Meteorological Service has used a Robertson-Berger meter (RB meter) to monitor solar UV-B radiation for the past decade. The radiometric properties of the instrument have been analyzed and agree with the standard values published by Berger. A detailed theoretical treatment of the RB meter response that fully accounts for its cosine response is presented. Field measurements made with the RB meter and with a double monochromator spectral radiometer were used to validate the theoretical model and to derive a calibration for the RB meter. Only cloud-free data were considered so that the downward radiation field at the surface could be modeled as the sum of direct solar and isotropic diffuse components. The imperfect cosine responses of both instruments were modeled. A RB meter count was found to equate to 0.25 ± 0.02 Jm referenced to 300-nm radiation at vertical incidence. © 1993 Optical Society of America

On Developing a Tropical Cyclone Archive and Climatology for the South Indian and South Pacific Oceans

International audienceTropical cyclones (TCs) are the most dangerous and damaging weather phenomena to regularly affect countries in the South Indian (SIO) and the South Pacific (SPO) Oceans. The year-to-year impact varies, and historical records demonstrate significant interannual variability in TC frequency and spatial distribution of TC tracks. Additionally, the climate is changing on a global scale (IPCC 2007) and it is important to understand how a warmer climate may affect TC activity. Numerous studies on TC activity in various regions of the northern and southern hemispheres have been completed with the aim of developing TC climatologies and establishing driving forces behind TC temporal and spatial variability

Perception of a chronic volcanic hazard: persistent degassing at Masaya volcano

This study takes a combined qualitative and quantitative approach to examining the chronic hazard posed by persistent degassing at Masaya volcano, Nicaragua. The gas is a highly salient threat in communities surrounding Masaya volcano, with the elevated salience level of his invisible hazard deriving from the highly perceptible impacts of the degassing; these include individual and material impacts such as increased prevalence of self-reported respiratory disease and decreased crop diversification and productivity. Qualitative results concur with findings from a quantitative assessment of ambient SO2 exposure using diffusion tubes: the current level of SO2 degassing far exceeds international guideline values, making it a likely cause of adverse health effects for the general population. Conversely contaminant levels of heavy and toxic metals in foodstuffs were found to be below international standards. A community-based integrated hazard mitigation approach identified by this research is the cultivation of crops, particularly pineapple (Ananas comosus) and pitaya (Hylocereus sp.), that are better able to withstand the local environmental conditions (e.g. increased atmospheric SO2 and acid gas deposition). Despite this, little is known regarding disaster response and risk reduction at the community level and the gas hazard is largely overlooked. This shows large scope for increasing resilience in collaboration with the community, through for example the development of community-level risk management committees, improvement and implementation of (gas) mitigation strategies and disaster preparedness approaches. By reducing the impacts of the chronic hazard posed by persistent volcanic degassing, resilience to acute hazards is also likely to improve