SciDev.Net

This feature article, written by members of the UN Operational Satellite Applications (UNOSAT) programme, outlines how satellite technology can improve emergency relief after a natural disaster.

UNOSAT uses satellite data to produce maps and damage reports for nongovernment organisations, intergovernmental agencies and disaster managers in emergency situations. The authors describe how the process works — from receiving a relief agency's phone call to collecting and analysing relevant satellite data.

They argue that satellite data, when combined with ancillary data such as road maps or population distribution, can help aid workers navigate affected areas and provide estimates of the number of people likely to be affected by, for example, floods or landslides.

The authors describe the range of satellite sensors used by UNOSAT, explaining the advantages of different types of data depending on the disaster. For example, radar imagery, which is unaffected by cloud, is particularly useful to monitor flooding, whereas high resolution optical data is better for earthquake damage assessment.

This paper discusses likely future changes in tropical cyclones, questioning whether they will become more intense following higher sea surface temperatures. The author outlines the different approaches currently taken to climate modelling and discusses the results of characterising current and future climate using the Max Planck Institute for Meteorology in Hamburg model, comparing them to observations.

Most climate models predict stronger tropical cyclones in a warmer climate, as an increase in latent heat provides more energy for the storms. But the author claims there is less evidence for a reduction in the frequency of storms in a warmer climate. Still, such a reduction could result from a general weakening of large-scale atmospheric circulation (which reduces the number of cyclones) caused by the rapid increase in water vapour that would follow a rise in global temperatures.