Environmental engineers at Duke University have demonstrated that sharp contrasts in relatively small land features play a substantial role in local weather developments, which can in turn influence larger climate trends.
The study shows that the addition of such detailed data, which is currently overlooked in climate and weather forecast models, should make such predictions more accurate.
“Our research illustrates that landscape heterogeneity, such as croplands next to a city, or a lake next to a forest, can lead to more powerful thunderstorms,” said Nathaniel Chaney.
“What makes this important is that the scale at which these patterns happen is smaller than what we can include in current global models,” added Jason Simon.
Whether making long-term global climate predictions or short-term weather predictions, climatologists and meteorologists turn to a small number of global models. One of the limitations of these models is the scale of the calculations. To avoid months of simulation processing, these models split the Earth’s surface into boxes measuring between 10 to 100 kilometers per side. Variables such as temperature, moisture and wind speed are directly calculated at each node where the corners of these boxes meet but are interpolated or averaged for all the space between them.
“That’s a large distance between points, in which there’s plenty of patterns causing changes on their own,” said Simon. “It’s a whole aspect of weather that’s being missed. And if it involves clouds, then it’s going to have a large impact on the energy balance in relation to climate change on a global scale.”
In their study, Simon and Chaney used a higher-resolution weather model, the Weather and Research Forecasting model (WRF) to see what effect sharply defined changes in soil moisture at a 100-meter spatial resolution have on cloud formation.
The results showed that sharp differences in landscape at these scales can have a disproportionately large effect on the formation of clouds. For example, a drier, hotter area next to a cooler, moister area—like an area where plains and city meet—will create surface atmospheric pressure differences between the dry and moist regions that lead to the enhanced formation of clouds.
https://phys.org/news/2021-10-small-sharp-landscape-contrasts-refines.html