ATC in 2011, by the Numbers
World Cities Plotted by Climatological Normals, January

World Cities Plotted by Annual Climatological Normals


On these charts, a selection of world cities are plotted according to their average annual temperature and average annual sunshine hours, with the size of the bubble for each city proportional to the average annual precipitation. The display of information in this way allows us to identify quickly some differences between the normal climate in different locations. Miami and Honololu, for instance, are very similar in average annual temperature, and almost the same in sunshine, but Miami has much more rainfall than Honolulu. 

The charts are shown with the x and y axes going to zero in the plot above, to get some sense of the range of variation in the data, and in the chart below the data are plotted to fit the chart, so that we can more easily identify the location of the cities. Atlanta has a similar annual temperature to Osaka, and similar precipitation, but there are about 40% more sunshine hours in Atlanta each year than in Osaka. That difference is clearly something to consider if we think about how, for example, ultradwarf bermudagrass greens would perform, or should be managed, in those different locations. 

Photosynthesis is affected by temperature, light, water availability, and leaf nitrogen content. Turfgrass managers control the nitrogen by judicious application of fertilizer, and the water availability is controlled partly through precipitation and partly through supplemental irrigation. Light and temperature, then, stand out as the uncontrollable influences on photosynthesis. In the warm-season areas of the United States, there tends to be relatively high sunshine. It is normal to have 2500, 3000, or even 3500 sunshine hours in a year. So in the United States, much of the grass selection, when it comes to warm-season (C4) grasses, is just a matter of temperature -- "is this a warm-season area, by temperature, or not?" 

In Asia, there tends to be less sunshine. If we compare Hong Kong with Miami, we see that Miami is slightly warmer, and Hong Kong has a bit more precipitation, but there is a huge difference in sunshine hours, with Miami having on average about 70% more sunshine hours than at Hong Kong. Does this have an affect on turfgrass performance? Yes! We see Zoysia matrella thriving in Hong Kong, and Singapore, and Tokyo, all cities where the sunshine hours are relatively low. Bermudagrass, on the other hand, performs relatively poorly in these same cities, and requires special care to keep in a playable condition. 



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