Collaborative Research: A potential new dust source in the southern hemisphere: Reactivation of the Kalahari dunes

南半球潜在的新沙尘源：喀拉哈里沙丘的重新激活地球上大气沙尘的主要来源位于干旱地区，目前，大多数活跃的沙尘源位于北半球，占全球沙尘排放量的90%以上。虽然目前来自南半球的沙尘排放的贡献相对较低，但由于土地利用或气候变化导致的植被覆盖减少为出现新的沙尘源区提供了可能。喀拉哈里沙漠是南半球一个潜在的大沙尘源，由于可能失去植被覆盖，它很容易重新动员起来。喀拉哈里沙丘的重新激活和随后的粉尘排放有可能对南半球的大气成分和生物地球化学循环造成相当大的变化。令人惊讶的是，沙丘活动对南部喀拉哈里沙漠沙尘排放的影响从未被研究过。此外，尚不清楚恢复的沙丘是否能支持与稳定状态下生态系统相同的生物量。本研究的目的是调查喀拉哈里环境对气候和土地利用变化的响应。它将评估土地覆盖和灰尘排放的变化，这些变化是由于预计南部非洲内陆的干旱化、木本植物的大规模侵蚀以及这个以畜牧用地为主的区域人口和对动物产品需求的增加造成的。这项研究将揭示气候变化和过度放牧对南半球最脆弱的干旱地区之一的大规模影响。通过在博茨瓦纳退化和管理良好的牧场进行各种实地测量，它将对喀拉哈里环境及其人民面临的自然和人类威胁进行综合评估，并对不同土地利用战略的可持续性进行评估。这些评估将为其他环境敏感干旱地区的土地使用者和管理者提供重要信息。除了对非洲的区域影响之外，这项研究还将对喀拉哈里沙漠潜在的粉尘排放进行定量评估，这可能会大大改变南半球大气的组成和生物地球化学。由于这项工作的横切性质，它是由NSF？地貌学与土地利用动力学、地理与空间科学、地球科学仪器与设施以及国际科学与教育办公室。

A potential new dust source in the southern hemisphere: Reactivation of the Kalahari dunesThe main sources of atmospheric dust on Earth are located in drylands and at present, most of the active dust sources are in the northern hemisphere, which accounts for more than 90% of global dust emissions. Although, currently, the contribution of dust emission from the southern hemisphere is relatively low, reductions in vegetation cover due to land use or climate change provide the potential for new source areas to emerge. The Kalahari Desert is a potentially large dust source in the Southern Hemisphere, which is prone to remobilization in response to possible losses of vegetation cover. Reactivation of the Kalahari dunes and subsequent emission of dust has the potential to cause considerable changes to the atmospheric composition and biogeochemical cycling of the Southern Hemisphere. Quite surprisingly, the impact of dune activation on the regime of dust emissions from the Southern Kalahari landscape has never been investigated before. Moreover, it is not clear whether reactivated dunes could support the same biomass as the ecosystem in its stable state. The objective of the proposed research is to investigate the response of the Kalahari environment to changing climate and land use. It will assess changes in land cover and dust emissions resulting from the predicted aridification of interior southern Africa, large scale encroachment of woody plants, and increasing population and demand for animal products from this region dominated by pastoral land use. This study will shed light on the large scale implications of climate change and overgrazing in one of the most vulnerable arid landscapes in the southern hemisphere. Through a variety of field measurements both in degraded and well managed grazing lands in Botswana, it will provide an integrated assessment of the natural and human threats faced by the Kalahari environment and its people, and allow for an evaluation of the sustainability of different land use strategies. These assessments will provide critical information for land users and managers in other environmentally sensitive arid regions. Beyond the regional impacts in Africa, this research will provide a quantitative assessment of the potential dust emissions from the Kalahari, which may considerably alter the composition and biogeochemistry of the atmosphere of the Southern Hemisphere. Because of the crosscutting nature of this work, it is supported by NSF?s programs in Geomorphology and Land-use Dynamics, Geography and Spatial Sciences, Earth Science Instrumentation and Facilities, and Office of International Science and Education.