Collaborative Research: Sensitivity of Regional Climate Due to Land-cover Changes in the Eastern United States Since 1650

该项目使用模型模拟来研究自17世纪中期以来土地利用和土地覆盖变化对美国东部气候的影响。该项目基于一个新的数据集，“重建的历史土地覆盖和生物物理参数”数据集，它使用36个土地覆盖类别来描述美国东部(西经97度以东，贯穿堪萨斯州)四个代表性年份的土地覆盖：1650年、1850年、1920年和1992年。从1650年到1920年期间，出现了大规模的森林砍伐和退耕还林，随后是从1920年到1992年的部分重新造林，所有这些都被记录在历史土地覆盖数据集中。从森林到草地或农田的变化可以在几个方面影响气候。例如，农作物和牧草的反照率较高，它们的颜色比森林浅，因此反射更多的入射阳光，可能会导致地表温度下降。历史土地覆盖数据集还记录了湿地的减少，这可能会对降雨量产生影响。使用陆地-大气区域气候模式的模拟被用来评估不同的陆面条件对美国东部气候条件(主要是温度和降雨)的影响。研究土地利用和土地覆盖变化的气候影响具有社会和科学意义，因为它可以帮助我们识别人类引起的气候变化，这可能需要适应和缓解策略。除了其研究成果的社会价值外，该项目还将通过在当地中高分校开展主要调查人员的外联活动，产生更广泛的教育影响。该项目还将支持一名研究生，从而为这一研究领域的下一代科学工作者提供教育和培训。

This project uses model simulations to study the effect of land use and land cover change on the climate of the eastern US since the mid-1600s. The project is based on a new dataset, the "Reconstructed Historical Land Cover and Biophysical Parameter" dataset, which uses 36 land-cover categories to describe landcover over the eastern US (east of the 97W meridian, which runs through Kansas) for four representative years: 1650, 1850, 1920, and 1992. The period from 1650 to 1920 saw extensive deforestation and conversion to cropland, which was followed by partial reforestation from 1920 to 1992, all of which is captured in the historical land cover dataset. The change from forest to grassland or cropland can affect climate in several ways. For example, the higher albedo of crops and grasses, which are lighter in color than forests and thus reflects back more incident sunlight, could cause a reduction in surface temperature. The historical land cover dataset also documents a reduction in wetlands, which could be consequential for rainfall. Simulations using a land-atmosphere regional climate model are used to assess the impact of the different land surface conditions on climatic conditions (primarily temperature and rainfall) in the eastern US climate.Research on the climatic effects of land use and land cover change is of societal as well as scientific interest, as it can help us to identify human-induced climate changes which are likely to require strategies for adaptation and mitigation. In addition to the societal value of its research findings, the project will have educational broader impacts through the outreach activities of the principal investigators at local middle and high scools. The project will also support a graduate student, thereby providing education and traning for the next generation of the scientific workforce in this research area.