The Impacts of Tropical Deforestation on Regional and Global Hydroclimate

该项目遵循PI进行的初步环流模型（GCM）研究，该研究发现，热带地区的森林砍伐，通过与厄尔尼诺事件期间产生的类似的罗斯比波激活的远相关，对其他地区的降雨有重大影响。他们特别发现，美国中西部是受亚马逊河流域和中非春季和夏季森林砍伐影响最严重的大陆地区，而春季和夏季的降雨对该地区的农业至关重要。该研究提出了两种更可靠实验的想法，它们是这项研究的基础：*在初步研究中进行的模拟可以通过表现更现实的强迫条件，如过去几十年观测到的海面温度和观测到的森林砍伐模式，得到相当大的改进；此外，用不同的气候模式再现这些模拟将有助于提高对这种遥相关的模式和强度的信心。本研究旨在利用三个主要的GCM: NCAR社区气候系统模型、NASA戈达德太空飞行中心GCM和PI的海洋-陆地-大气模型（OLAM）来研究这些想法。这项研究的最终目标是量化由于过去和现在热带地区的森林砍伐而导致的所有大陆地区降水的变化。更广泛的影响：在进行本研究的过程中，将对气候模式进行相互比较，并对其模拟全球降水的能力进行评估。该项目还将有助于引入新一代地球系统模式（即海洋-陆地-大气模式- OLAM），这将有助于推进未来的气候研究。因此，该项目有可能提高科学家预测由于土地覆盖/土地利用变化引起的全球环境变化的能力，并且与具有社会重要性的问题相关。

This project follows a preliminary general circulation modeling (GCM) study conducted by the PI who found that deforestation of tropical regions, through teleconnections involving the activation of Rossby waves similar to those produced during El Nino events, has a significant impact on the rainfall of other regions. In particular, they found that the US Midwest is the continental region the most severely affected by the deforestation of Amazonia and Central Africa during spring and summer, when rainfall is crucial for agriculture in that region. Two ideas for a more robust experiment arose from that study and are the basis of the research:* The simulations performed in the preliminary study could be considerably improved by representing more realistic forcing conditions such as observed sea-surface temperatures (SSTs) and observed deforestation patterns during the past few decades;* Furthermore, reproducing these simulations with different climate models would contribute to improving confidence in the pattern and strength of such teleconnections. This research is aimed at studying these ideas using three major GCMs: the NCAR Community Climate System Model, the NASA Goddard Space Flight Center GCM and the PI's Ocean-Land-Atmosphere Model (OLAM). The ultimate goal of the study is to quantify the change of precipitation in all continental regions due to past, and present deforestation of tropical regions.Broader Impact: In the process of performing this research, an intercomparison of climate models and an evaluation of their capability of simulating global precipitation will be conducted. This project will also help introduce a new generation of earth system model (namely, the Ocean-Land-Atmosphere Model -- OLAM), which will help advance future climate research. Thus, the project has potential to improve scientists' ability to project global environmental change due to land cover/land use change and is relevant to issues of societal importance.