COLLABORATIVE RESEARCH: Complexity and Paleodynamics of Natural Sand Dune Fields

BSTRACTCTCOMPLICITY AND PALEODYNAMICS of Natural沙丘FIELDSGary KocurekEAR-0106603沙丘呈现了一些在地球和火星等其他星球上看到的最有趣的图案。沙丘是风吹沙粒时形成的，沙粒堆积成小土堆，最终演变成装饰在日历和邮票上的优美形状。风的特征，如风的方向和沙子的供应，以这样一种方式印在沙丘的图案上，只需仔细检查沙丘的图案，就可以说出导致沙丘形成的气候条件。随着风和沙子的供应随着时间的推移而变化，沙丘的模式也在以尚未完全描绘的方式慢慢变化。储存在非洲、中东、亚洲、澳大利亚和北美大沙丘地区过去数千年到数万年的气候信息，可能会为预测区域气候和景观对人类引起的全球气候变化的反应提供关键的理解。PIS的目标是开发一种从沙丘模式推断过去气候的方法，并将其应用于三个自然沙丘地区。为实现这一目标，他们开发了跨越沙丘和沙丘领域对气候变化作出反应的一系列时间周期的数值模型：(1)沙丘领域总体特征的模型，包括沙丘之间的间距及其方位(数千年)；(2)沙丘顶部及其峰线运动的模型(数百年)；和(3)沙丘形状变化的模型(数十年)。这些模型将被用于研究加利福尼亚州东南部的Algoones沙丘田、纳米比亚西部纳米比亚沙漠的沙丘和毛里塔尼亚西部沙漠的沙丘。PI对过去气候的解释将通过尝试在充满沙子的风洞中使用他们的气候推断来重新创建这三个沙丘区域的模式来进行测试。

BSTRACTCOMPLEXITY AND PALEODYNAMICS OF NATURAL SAND DUNE FIELDSGary KocurekEAR-0106603Fields of sand dunes present some of the most intriguing patterns seen on Earth and other planets, such as Mars. The dunes form when wind transports sand grains, causing them to pile up into small mounds that eventually evolve into the graceful shapes that adorn calendars and postage stamps. The characteristics of the wind, such as its direction and the supply of sand, are imprinted on the pattern of dunes in such a way that it is possible, just by carefully examining the dune pattern, to say something about the climatic conditions that lead to its creation. As winds and sand supply change through time, the pattern of dunes slowly changes as well in ways that are not yet fully delineated. The information about climate over the past thousands to tens of thousands of years stored in the great sand dune fields of Africa, the Middle East, Asia, Australia and North America might provide critical understanding in predicting the reaction of regional climates and landscapes to human-induced global climate change. PIs aim is to develop a methodology for inferring past climate from dune patterns and to apply it to three natural dune fields. To achieve this goal, they have developed numerical models that span the range of time periods over which dunes and dune fields can react to changes in climate: (1) a model for the overall characteristics of dune fields, including spacing between dunes and their orientation (thousands of years); (2) a model for the motion of the trace of the tops of dunes, their crestlines (hundreds of years); and (3) a model for the changes in shapes of dunes (tens of years). These models will be used to investigate the development of the Algodones dune field in southeastern California, the dunes of the Namibian desert in western Namibia, and the dunes of the deserts of western Mauritania. The interpretations PIs derive regarding past climate will be tested by attempting to recreate the patterns of these three dune fields using their climatic inferences in a wind tunnel filled with sand.