Obviously, this does not explain very much of the natural variation in denudation rate. This model gives an exponential decay of elevation with a time constant of about 50 My. A better job can be done by assuming that the denudation rate is dependent on average elevation and precipitation, but even this is a very simple-minded model of the immense complexity with which topography controls the erosion rate. Even after allowing for both precipitation and average elevation, there remains considerable variation in the 45 drainage basins' erosion rates that is not explained in this simple model. Much of this variation can be attributed to the fact that average elevation is only a poor proxy for the way topography controls the erosion rate.
Erosion tends to be catastrophic and localized.
The first priority is to obtain an accurate, high-resolution global DEM that can produce an accurate slope map. These data allow us to assess how topographic erosion control actually works. It would also have new commercial and engineering applications, as well as geologic applications, e.g., potential identification of buried active faults. Differential interferometry may not be able to detect major or minor erosional events because of the previously mentioned decorrelation problem. Belts in Taiwan, Zagros, the Himalayas, and Papua, New Guinea are possible targets.