Digital Elevation Models (DEM’s)
Digital Elevation Models are the starting point of all Terrain Analysis projects. The effect of different altitudes on vineyards can be seen across the globe.
It does not only affect the temperature, but a lot of phenological and physiological processes.
The value that atmospheric temperature drops or increase with change in elevation is called the “Lapse Rate”. Under normal atmospheric conditions the average atmospheric lapse rate results in a temperature decrease of 6.4C°/km (this may vary). This means that it is generally cooler the higher you get. This can impact budding, flowering, your ripening period and ultimately your wine style.
Knowing at which elevation your blocks are can give you a comparative advantage to measuring different styles of different varieties in different regions.
In a study funded by Winetech and completed by Heinrich Schloms of VinPro, together with a bunch of experts, it was determined that Shiraz was specifically sensitive towards certain terroir factors such as elevation and average minimum night/day temperature. This had an enormous impact on the style of Shiraz produced in the Western Cape (taking wine making techniques out of the equation) (click here for the article)
But this is not only the case with Shiraz. All varieties will react different with change in elevation. This is just one of the things that a DEM can show you. From the DEM you can create a lot of other interesting views, but I will cover that later.