TY - JOUR
T1 - Forest Disturbance Feedbacks From Bedrock to Atmosphere Using Coupled Hydrometeorological Simulations Over the Rocky Mountain Headwaters
AU - Forrester, Mary M.
AU - Maxwell, Reed M.
AU - Bearup, Lindsay A.
AU - Gochis, David J.
N1 - Funding Information:
We gratefully acknowledge computing support by the National Center for Atmospheric Research (NCAR) Computational and Information Systems Laboratory (CISL) on Yellowstone and Cheyenne. Funding was provided by the National Science Foundation through its Water, Sustainability and Climate (WSC) program and NSF award number 1204787. We would like to thank Aaron Porter for his help and advice in statistical methods. Finally, we thank our editor, Allison Steiner, and our three anonymous for their constructive suggestions, which greatly improved the robustness of the analysis and the quality of the manuscript. ParFlow and WRF are publicly available models, and the coupled hydrologic-atmospheric platform is available at https://github. com/parflow. All inputs necessary to reproduce the modeling data presented here are located at http://github.com/ forremm0/forrester-PFWRF. Model results are hosted on a private server and are available upon request (mforrest@mines.edu).
Publisher Copyright:
©2018. American Geophysical Union. All Rights Reserved.
PY - 2018/9/16
Y1 - 2018/9/16
N2 - The mountain pine beetle (MPB) has dramatically influenced high-elevation pine forests of western North America, with recent infestations causing millions of acres of forest mortality and basal area loss. While ecohydrologic implications of infestation have been studied extensively in recent years, few have explored atmospheric feedbacks of widespread canopy transpiration loss or the potential role of groundwater to amplify or mitigate changes to land energy. This work presents bedrock-to-atmosphere simulations of coupled meteorological and hydrologic states over the Colorado headwaters. Analyses compare configurations with (1) default land surface parameters and (2) disturbance simulations with adjusted transpiration parameters in infested cells. An analysis of variance was conducted to identify regions of significant response to mountain pine beetle. Changes to increased soil moisture and Bowen ratios were found to be statistically significant in MPB-infested areas and in nonlocal valleys, while planetary boundary layer (PBL) response was significant only in high elevations of the headwaters watershed. Temperature-humidity covariance was evaluated using mixing diagrams; the results suggest that increased surface Bowen ratios from MPB could affect entrainment of dry air from the troposphere. The PBL is hotter, drier, and higher under infested forest conditions, which could have implications to atmosphere-vegetation feedbacks and forest drought stress. Finally, land-atmosphere coupling was sensitive to antecedent subsurface moisture. Regions with shallow water tables exhibit greater magnitude response to MPB at the surface and in the PBL, a finding that has repercussions for ecosystem resilience and hydrologic representation in meteorological modeling.
AB - The mountain pine beetle (MPB) has dramatically influenced high-elevation pine forests of western North America, with recent infestations causing millions of acres of forest mortality and basal area loss. While ecohydrologic implications of infestation have been studied extensively in recent years, few have explored atmospheric feedbacks of widespread canopy transpiration loss or the potential role of groundwater to amplify or mitigate changes to land energy. This work presents bedrock-to-atmosphere simulations of coupled meteorological and hydrologic states over the Colorado headwaters. Analyses compare configurations with (1) default land surface parameters and (2) disturbance simulations with adjusted transpiration parameters in infested cells. An analysis of variance was conducted to identify regions of significant response to mountain pine beetle. Changes to increased soil moisture and Bowen ratios were found to be statistically significant in MPB-infested areas and in nonlocal valleys, while planetary boundary layer (PBL) response was significant only in high elevations of the headwaters watershed. Temperature-humidity covariance was evaluated using mixing diagrams; the results suggest that increased surface Bowen ratios from MPB could affect entrainment of dry air from the troposphere. The PBL is hotter, drier, and higher under infested forest conditions, which could have implications to atmosphere-vegetation feedbacks and forest drought stress. Finally, land-atmosphere coupling was sensitive to antecedent subsurface moisture. Regions with shallow water tables exhibit greater magnitude response to MPB at the surface and in the PBL, a finding that has repercussions for ecosystem resilience and hydrologic representation in meteorological modeling.
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U2 - 10.1029/2018JD028380
DO - 10.1029/2018JD028380
M3 - Article
AN - SCOPUS:85052903849
SN - 2169-897X
VL - 123
SP - 9026
EP - 9046
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
IS - 17
ER -