Precipitation and temperature maxima: A study across the Southern Great Plains winter wheat region

Authors: Flanagan, Paul

Submitted to: Earth Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2024
Publication Date: 8/28/2024
Citation: Flanagan, P.X. 2024. Precipitation and temperature maxima: A study across the Southern Great Plains winter wheat region. Earth Interactions. https://doi.org/10.1175/EI-D-23-0019.1.
DOI: https://doi.org/10.1175/EI-D-23-0019.1

Interpretive Summary: Given the importance of agriculture in the Southern Great Plains, the interactions between water and climate are important. For this, knowledge of temperature and precipitation and how they change through the year is critical. Previous work looking into temperature and precipitation peaks found years in which temperature and precipitation maxima were reversed, or that the temperature maximum occurred before the precipitation maximum. However, this previous work did not investigate temperature or precipitation during these normal or reversed growing season climates, and thus the impact these two different regimes have on agriculture is unknown. This study investigates the differences between the normal growing season climate, or a precipitation maximum before temperature, and the reversed climate. Using station observations, results show that the normal and reversed growing season climates are distinctly different in temperature and precipitation through the growing season. Namely that the normal growing season climate is seen with a wetter spring and a dry and hot summer while the reversed climate shows a warmer and drier spring with a very wet summer. These results show that the previously identified normal and reversed growing season climates have different impacts on water resources and thus agriculture throughout the Southern Great Plains growing season. USDA is an equal opportunity provider and employer.

Technical Abstract: Given the importance of agriculture to the Southern Great Plains (SGP), accurate knowledge of growing season temperatures and precipitation is critical. Previous research into growing season precipitation and temperature maxima revealed a distinct feature of the GP climate, the asynchronous difference index (ADI) and positive and negative ADI periods. The goal of this research is to further investigate the ADI within a specific agricultural region of the SGP, the winter wheat region, and to quantify the temporal evolution of temperature and precipitation during positive and negative ADI growing seasons. For this, Global Historical Climatology Network (GHCN) daily station data were analyzed across the growing season (March to September) from 1900 to 2020. Results show that differences appear in the temperature and precipitation fields when comparing positive and negative growing seasons. Namely, positive ADI growing seasons show a wetter and cooler start and a hotter and dry end, while negative ADI growing seasons depict less precipitation and warmer temperatures early on, and much more precipitation and cooler temperatures later. Further, the results of this work reveal two different depictions of the SGP climate. First, a wet spring with a hot and dry summer noted through positive ADI. Then, times with a dry and warmer spring with a very wet and cooler summer seen in negative ADI growing seasons. Overall, these results are a next step in the analysis into the implications of ADI on the SGP climate, namely on the interannual impacts of different temperature and precipitation regimes on agriculture. USDA is an equal opportunity provider and employer.