Kilometer-scale modeling better reflects the relationship between land and precipitation

The relationships between topography and precipitation were established using the method of multi-scale geographically weighted regression, and the results were evaluated against weather station observations. First, they reconfirmed that kilometer-scale DDMs better describe the observed precipitation characteristics than DDMs operating at quarter-degree resolution. Delving deeper into the reasons why, it was found that the small-scale topography played a dominant role in the observed precipitation distribution at most weather stations in eastern China, and the kilometer-scale DDM reproduced these observed effects of topography on precipitation more accurately than the quarter-degree DDM. These results have been published in Atmospheric and Oceanic Science Letters. This was because of its advantages in reflecting the scale effects of the different factors on the distribution of the precipitation based on the bandwidth; that is, a factor with a smaller bandwidth had a stronger influence on the spatial heterogeneity of precipitation. "Compared with the quarter-degree DDM, the kilometer-scale simulation had the advantages of a finer horizontal resolution and it was able to more precisely describe the sub-grid topographical features and capture the influences of sub-grid surface variations in precipitation. The discrepancies arising from coarse-resolution modeling of the topography-precipitation relationship might be a cause of mismatched precipitation between observations and simulations," explains Prof. Gao. By expounding the mechanisms underpinning the differences between kilometer-scale and quarter-degree DDM results from the perspective of the relationships between topography and precipitation in eastern China, this research emphasizes the key role played by sub-grid variations in the underlying surface in the simulation of precipitation. Citation: Kilometer-scale modeling better reflects the relationship between land and precipitation retrieved 6 December 2022 from https://phys. org/news/2022-12-kilometer-scale-relationship-precipitation.