Collaborative Research: RAPID: Typhoon Merbok in coastal western Alaska: Extent of flooding and impacts on plant communities and ecosystem function

合作研究：RAPID：阿拉斯加西部沿海的台风梅尔博克：洪水的程度及其对植物群落和生态系统功能的影响

• 批准号: 2302105
• 负责人: A Joshua Leffler
• 金额: $ 6.34万
• 依托单位: South Dakota State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2302105&HistoricalAwards=false
• 关键词: Collaborative; Research; RAPID; Typhoon; Merbok

On September 16th, 2022, the Yukon-Kuskokwim (YK) Delta of western Alaska was hit by ex-Typhoon Merbok, a storm that many residents of the area described as the worst in their lifetime. The storm surge was several meters in height, and inland locations that normally do not flood under the highest tides of the year were inundated, resulting in extensive loss of homes, fishing boats, and subsistence cabins. This storm was unusual not only because of its size, but also its timing as the ground was not yet frozen or snow-covered. Since the Delta is flat, salty water extended for about a dozen or more miles inland, flooding Alaskan villages, hunting and fishing camps, and landscapes that are not acclimated to frequent floods. In this work, scientists will perform aerial and ground surveys to map the extent of the floods by looking for driftwood and other vegetation left behind by retreating water. Where driftwood is found, scientists will determine the amount of sediment deposited and measure pond salinity to test whether ponds switched from freshwater to salty water during the flood. The researchers will then set-up areas to observe longer-term effects of the floods on plants and the release of greenhouse gases to the atmosphere. As climate change contributes to larger and more frequent storms like Typhoon Merbok, understanding the consequences of them is becoming increasingly important to better prepare for the impacts of these storms on the landscape and the people who live in their path. This research consists of three components to address the extent and impact of Typhoon Merbok on the YK Delta region. First, researchers will conduct aerial and river surveys of drift lines and salinity along four rivers near Chevak, Alaska. For aerial surveys, transects ca. 30 km long and 2 km apart will be flown in mid-autumn 2022 with two observers photographing drift lines. All photographs will be geolocated. For river surveys, researchers will locate and sample debris, collect soil to quantity sediment deposition, and sample water bodies for salinity. Second, researchers will use high-resolution remotely-sensed imagery to locate fields of larger debris over a greater extent of the YK Delta. The elevation of debris from components one and two will be extracted from available LIDAR and structure-from-motion elevation models to determine the elevation of flood waters. Finally, researchers will establish monitoring plots to test hypotheses about impacts of the flooding, including evaluating changes to plant community composition, CO2 flux due to salt-kill, and CH4 flux due to suppression of methanogenesis by sulfates that occur in sea water. The project will produce valuable maps and data on the impacts of Merbok on the YK Delta Region, which will be made publicly available and be shared directly with local communities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

2022年9月16日，阿拉斯加西部的育空-库斯科维姆（YK）三角洲遭受了前台风“默克”的袭击，该地区的许多居民称这是他们一生中最严重的风暴。风暴潮高达几米，通常在一年中最高的潮汐下不会被洪水淹没的内陆地区被淹没，导致大量房屋、渔船和生存小屋的损失。这场风暴的不寻常之处不仅在于它的规模，还在于它发生的时间，因为地面还没有结冰或被雪覆盖。由于三角洲地势平坦，咸水向内陆延伸了十几英里甚至更多，淹没了阿拉斯加的村庄、狩猎和捕鱼营地，以及那些不适应频繁洪水的景观。在这项工作中，科学家们将进行空中和地面调查，通过寻找漂流木和其他因水退去而留下的植被来绘制洪水的范围。在发现浮木的地方，科学家将确定沉积物的沉积量，并测量池塘的盐度，以测试池塘是否在洪水期间从淡水转向咸水。然后，研究人员将建立一些区域来观察洪水对植物的长期影响以及向大气中释放的温室气体。由于气候变化导致了更大、更频繁的风暴，如台风默克，了解其后果变得越来越重要，以便更好地为这些风暴对景观和沿途居民的影响做好准备。本研究由三个部分组成，以探讨台风梅博克对YK三角洲地区的影响程度。首先，研究人员将对阿拉斯加切瓦克附近四条河流的漂流线和盐度进行空中和河流调查。在空中测量方面，将在2022年中秋飞行约30公里长，相隔2公里的横断面，由两名观察员拍摄漂移线。所有照片将被定位。在河流调查中，研究人员将对碎片进行定位和采样，收集土壤以测量沉积物沉积，并对水体进行盐度采样。其次，研究人员将使用高分辨率遥感图像来定位YK三角洲更大范围内的较大碎片区域。组件1和组件2的碎片高度将从可用的激光雷达和运动结构高程模型中提取，以确定洪水的高度。最后，研究人员将建立监测地块，以验证有关洪水影响的假设，包括评估植物群落组成的变化、盐杀死导致的CO2通量和海水中硫酸盐抑制甲烷生成导致的CH4通量。该项目将制作有关Merbok对YK三角洲地区影响的有价值的地图和数据，这些地图和数据将向公众开放，并直接与当地社区分享。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。