MSB-ECA: A Lengthening Vernal Window: How Vernal Asynchronies in Energy, Water, and Carbon Fluxes Impact Ecosystem Function

MSB-ECA：延长的春季窗口：能源、水和碳通量的春季异步如何影响生态系统功能

• 批准号: 1802726
• 负责人: Elizabeth Burakowski
• 金额: $ 29.86万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1802726&HistoricalAwards=false
• 关键词: MSB; ECA; Lengthening; Vernal; Window

The vernal window is the transitional period between winter and spring in the northeastern US, when air temperatures warm above freezing, snow melt begins, and forest canopies fully leaf out. The sequential order and timing of physical changes during this window plays a key role in the healthy functioning of seasonally snow-covered ecosystems. The vernal window is shorter following cold, snowy winters but lengthens when winters are warmer and snow packs are shallow or melt multiple times through the winter. When the vernal window gets longer, it can lead to a mismatch in the timing of key ecosystems processes. For example, earlier snowmelt in the spring can flush nutrients from soils before trees emerge from dormancy, preventing trees from accessing those vital nutrients during early spring growth. The vernal window is expected to lengthen given documented warming trends in winter climate, and, under higher emission scenarios may be eliminated altogether in more southerly locations. This study will integrate observations of snow, streamflow, and forest health to document historical changes in the length of the vernal window and use simulations to project future changes in the vernal window. Results will be use to assess the impact on key energy, water, and carbon transitions on ecosystem function, using the northeastern United States forests as a testbed. In collaboration with a local high school classroom, the investigators will develop a low-cost instrumentation suite constructed by students through an inquiry-based lab course that will allow students to track changes in the vernal window in their school yards. A Next Generation Science Standard compliant curriculum with units on energy balance, the carbon cycle, and hydrology will accompany the instrument kit, laying the groundwork for outdoor classroom inquiry on the environment. Previous studies have demonstrated the importance of winter coldness or snowpack as drivers of spring onset, however, it remains unclear how antecedent winter temperature and snowpack properties interact to influence the timing and duration of the vernal window. In addition, previous work has not investigated explicitly how biogeochemical asynchronies that result from longer lags between transitions in the longer vernal window can impact ecosystem function, which is essential for understanding the impact of environmental change. Rapid changes in winter conditions could lead to vernal asynchronies that have strong potential to alter energy, water, and carbon balances. The most extreme case is a shift into a snow-free regime in which the vernal window ceases to exist and is replaced by a prolonged period of increased net radiation into terrestrial and aquatic ecosystems between senescence and leaf out that may fundamentally alter ecosystem function. The work proposed here brings together large existing datasets and process-based models that will be used to investigate explicitly 1) the relative importance of winter coldness and snowpack in altering the vernal window; 2) how longer vernal lags and windows impact ecosystem energy, water, and carbon balance; and 3) how future winter coldness and snowpack characteristics might lead to additional changes in the vernal window. The outcome of this process will be a regional, 30-year historical analysis of changes to energy, carbon, and water balances during the vernal window. Insight gained from this historical analysis will provide the ability to project future changes in not only vernal window length, but also the impact of changing energy, carbon, and water balances during the vernal window on ecosystem function.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.

春窗是美国东北部冬季和春季之间的过渡时期，气温高于冰点，雪开始融化，森林树冠完全落叶。在这一窗口期间，物理变化的顺序和时间对季节性积雪覆盖的生态系统的健康运作起着关键作用。在寒冷多雪的冬天之后，春季窗口会变短，但当冬天变暖和，积雪变浅或融化多次时，春季窗口会变长。当春季窗口变长时，可能会导致关键生态系统进程的时间不匹配。例如，春季较早的融雪可以在树木从休眠中苏醒之前将土壤中的营养素冲走，从而阻止树木在早春生长期间获得这些重要的营养素。考虑到冬季气候中有记录的变暖趋势，预计春季窗口将延长，在较高排放量的情况下，在更靠南的地区可能完全消失。这项研究将整合雪，径流和森林健康的观测记录的历史变化的春天窗口的长度，并使用模拟来预测未来的春天窗口的变化。结果将用于评估对关键能源，水和碳的过渡对生态系统功能的影响，使用美国东北部的森林作为试验台。研究人员将与当地一所高中的教室合作，开发一种低成本的仪器套件，由学生通过一门基于探究的实验室课程建造，让学生能够跟踪校园里春天窗户的变化。符合下一代科学标准的课程，包括能量平衡、碳循环和水文学单元，将伴随着仪器包，为户外课堂环境调查奠定基础。先前的研究已经证明了冬季寒冷或积雪作为春季开始的驱动因素的重要性，然而，目前尚不清楚前期冬季温度和积雪特性如何相互作用，以影响春季窗口的时间和持续时间。此外，以前的工作还没有明确调查，在较长的春季窗口过渡之间的较长的滞后所导致的生态地球化学的变化如何影响生态系统功能，这是理解环境变化的影响至关重要。 冬季条件的快速变化可能导致春季气候变化，这有很大的潜力改变能量，水和碳平衡。最极端的情况是转变为无雪状态，春季窗口不复存在，取而代之的是陆地和水生生态系统在衰老和落叶之间的长期净辐射增加，这可能从根本上改变生态系统的功能。本文提出的工作汇集了现有的大型数据集和基于过程的模型，这些模型将用于明确研究1）冬季寒冷和积雪在改变春季窗口方面的相对重要性; 2）春季滞后和窗口如何影响生态系统能量，水和碳平衡;以及3）未来冬季寒冷和积雪特征如何导致春季窗口的额外变化。这一进程的成果将是对春季窗口期间能源、碳和水平衡变化的区域性30年历史分析。从这一历史分析中获得的见解将提供预测未来变化的能力，不仅在春季窗口长度，而且在春季窗口期间变化的能量，碳和水平衡对生态系统功能的影响。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

项目成果

Snowmelt control on spring hydrology declines as the vernal window lengthens

• DOI: 10.1088/1748-9326/abbd00
• 发表时间: 2020-11-01
• 期刊: ENVIRONMENTAL RESEARCH LETTERS
• 影响因子: 6.7
• 作者: Grogan, D. S.;Burakowski, E. A.;Contosta, A. R.
• 通讯作者: Contosta, A. R.

Converting snow depth to snow water equivalent using climatological variables

使用气候变量将雪深转换为雪水当量

• DOI: 10.5194/tc-13-1767-2019
• 发表时间: 2019
• 期刊: The Cryosphere
• 作者: Hill, David F.;Burakowski, Elizabeth A.;Crumley, Ryan L.;Keon, Julia;Hu, J. Michelle;Arendt, Anthony A.;Wikstrom Jones, Katreen;Wolken, Gabriel J.
• 通讯作者: Wolken, Gabriel J.

Reforestation and surface cooling in temperate zones: Mechanisms and implications

• DOI: 10.1111/gcb.15069
• 发表时间: 2020-03
• 期刊: Global Change Biology
• 影响因子: 11.6
• 作者: Quan Zhang;M. Barnes;M. Benson;E. Burakowski;A. Oishi;A. Ouimette;Rebecca Sanders‐DeMott;P. Stoy;M. Wenzel;L. Xiong;K. Yi;K. Novick

Tracking Environmental Change Using Low-Cost Instruments during the Winter-Spring Transition Season

在冬春季节期间使用低成本仪器跟踪环境变化

• DOI: 10.1525/abt.2022.84.4.219
• 发表时间: 2022
• 期刊: The American Biology Teacher
• 作者: Burakowski, Elizabeth;Sallade, Sarah;Contosta, Alix;Sanders-DeMott, Rebecca;Grogan, Danielle
• 通讯作者: Grogan, Danielle