Blog Archives

Visualizing Drought

March 6, 2010
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Visualizing Drought

The impacts of drought depend on time-scale. On short time-scales, drought means dry soil. On long time-scales, it means dry rivers and empty reservoirs. A region may simultaneously experience dry conditions on one time-scale and wet conditions on another e.g. wet soil but low streamflow or visa versa. Standardized Precipitation Index (SPI) is a widely

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Ensemble Prediction

February 2, 2010
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Ensemble Prediction

Weather is unpredictable. Small differences in initial conditions can develop into big differences in the pattern of circulation, in the timing and location of cyclones, rainfall etc. This is true no matter how good the initial observing system is. The approach taken by organisations such as ECMWF or NCEP is to re-run numerical forecast models

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NCEP Global Forecast System

December 16, 2009
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NCEP Global Forecast System

Just about everyone is familiar with weather maps. There are many situations where it is useful to combine the underlying numerical weather data with other types of information. Accessing  the weather data is a necessary first step. The output from the U.S. National Centers for Environmental Prediction (NCEP) Global  Forecast System (GFS) is freely available.

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Mapping Biomes

November 20, 2009
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Mapping Biomes

Recently (2008) the European Space Agency produced GlobCover (ESA GlobCover Project, led by MEDIAS-France), the highest resolution (300m) global land cover map to date. GlobCover uses 21 primary land cover classes and many more sub-classes. Land cover classification (LCC) schemes divide the earth into biomes. Biomes are the simplest way to classify vegetation which can

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