Land-Surface Processes, Dust Sources, and Particulate Fluxes of the 1930s Dust Bowl Drought in the U.S. Great Plains

该研究项目将评估农业实践是否是1930年代沙尘暴干旱期间风蚀和全大陆沙尘暴的主要原因，因为过去80年一直假设。 该项目将为北美中部开发一个新的数据库，以评估自然和人为引起的地表过程对风蚀的空间和时间变化以及1930年代沙尘暴干旱的粉尘排放估计。 该项目将产生新的量化标准，以评估耕作的作用，随后的复耕，以及自然和人类相关过程之间的相互作用，导致1930年代前期风成沉积物和景观剥蚀的重新激活。 该数据库将提供适当的空间尺度，用于估算干旱地表的灰尘发射率以及灰尘对区域和全球大气微粒负荷的潜在影响。 许多地球系统模型强调了大平原在21世纪世纪极端干旱的脆弱性，干旱有可能超过20世纪30年代的条件，从而增加了风成活动加剧的可能性。 该项目加深了对1930年代干旱期间沙尘产生的时空变异性的了解，这将改进大气-陆地相互作用模型的参数化。 对这些复杂动力学的认识的提高将为如何更好地减缓大气粉尘负荷的增加提供见解，这会增加呼吸道，心血管和粉尘传播病毒疾病的过早死亡和发病风险。为了评估植被，相关的风过程以及大平原沙尘暴中心的沙尘源和通量的变化，调查人员将分析1936年至1939年的航空摄影。 目标区域将包括德克萨斯州和俄克拉荷马州狭长地带的持续干旱地区，堪萨斯、科罗拉多和新墨西哥州的邻近地表;以及内布拉斯加州西部沙丘和北达科他州西部的其他潜在沙尘源地区。 调查人员将在图像分析表明沙子和其他风吹颗粒在20世纪30年代积累的地点进行实地研究，从而深入了解沙尘暴沉积物的厚度，连续性和颗粒大小。 一系列的粉尘排放估计将来自分类的陆地表面的分布和经验分析的粉尘生产和释放类似的表面在美国西部这些粉尘释放估计将进行评估，新的现场测量的粉尘通量从土壤中使用的便携式原位风蚀实验室。

This research project will evaluate whether agricultural practices were the dominant cause for wind erosion and continent-wide dust storms during the 1930s Dust Bowl drought as has been assumed for the past 80 years. The project will develop a new database for central North America to assess the spatial and temporal variability of natural and human-induced surface processes on wind erosion and dust emission estimates for the 1930s Dust Bowl drought. The project will yield new quantitative criteria to evaluate the role of cultivation, subsequent re-plowing, and the interactions among natural and human-related processes that led to reactivation of antecedent aeolian deposits and landscape denudation in the 1930s. This database will provide appropriate spatial-scaling for deriving estimates of dust emissivity from drought-stricken surfaces and the potential contributions of dust to regional and global atmospheric particulate loads. Many Earth system models underscore the vulnerability of the Great Plains in the 21st century to extreme droughts, with drying having the potential to exceed conditions in the 1930s, thereby increasing the potential for heightened aeolian activity. The enhanced understanding provided by this project of the spatial and temporal variability in dust generation during the 1930s drought will improve parameterization of atmosphere-land interaction models. Improvements in knowledge of these complex dynamics will provide insights regarding how to better mitigate against increases in atmospheric dust loads, which pose with increased risks of premature mortality and morbidity from respiratory, cardiovascular, and dust-borne viral diseases.To assess changes in vegetation, associated wind processes, and dust sources and fluxes the heart of the Dust Bowl on the Great Plains, the investigators will analyze aerial photography from 1936 and 1939. Targeted regions will include persistent drought areas in the Texas and the Oklahoma panhandles, adjacent surfaces in Kansas, Colorado, and New Mexico; and other potential dust sources areas in the western Nebraska sand hills and in western North Dakota. The investigators will conduct field-based studies at sites where analysis of images indicates that sand and other wind-blown particles accumulated in the 1930s, thereby providing insights into thickness, continuity and particle sizes of Dust Bowl deposits. A range of dust emission estimates will be derived from the distribution of classified land-surfaces and from empirical analyses of dust production and release for analogous surfaces in the western U.S. These dust release estimates will be evaluated with new field measurements of dust flux from soils with the use of the portable in situ wind erosion lab.