| Term: | Nordenskjöld line |
| Definition: | The line connecting all places at which the mean temperature (C) of the warmest month is equal to 9 - 0.1k, where k is the mean temperature of the coldest month. (In degrees Fahrenheit the relationship becomes 51.4 - 0.1k.) This line fits the arctic tree line better than any other purely climatic isopleth hitherto tried. |