Mesoscale Simulations of the Land Surface Effects of Historical Logging in a Moist Continental Climate Regime

Abstract

An enhanced knowledge of the feedbacks from land surface changes on regional climates is of great importance in the attribution of climate change. To explore the effects of deforestation on a midlatitude climate regime, two sets of two five-member ensembles of 28-day simulations were conducted using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) coupled to the "Noah" land surface model. The four ensembles represented conditions in summer (August) and winter (February) across the northern mid-Atlantic United States before and after extensive late-nineteenth-century logging of hardwood forests in central and northern Pennsylvania. Prelogging ensembles prescribed a vegetative cover of an evergreen needleleaf forest; postlogging ensembles prescribed sparse vegetation and bare soil to simulate clear-cut deforestation. The results of the MM5 experiments showed a decided seasonality in the response of the land surface-atmosphere system to deforestation, with much stronger effects arising in summer. In August, deforestation caused a repartitioning of the surface energy budget, beginning with a decrease in the latent heat flux of more than 60 W m Ϫ2 across the land cover-forcing area, representing almost one-half of the latent heat flux under prelogging land cover. Concomitant with this decrease in evapotranspiration, mean 2-m air temperatures warmed by at least 1.5°C. Increases in sensible heat flux led to a 150-m mean increase in the height of the atmospheric boundary layer over the deforested area. Low-level atmospheric mixing ratios and total precipitation decreased under clear-cut conditions. Mean soil moisture increased in all model levels to 150 cm because of a decrease in vegetative uptake of water, except at the 5-cm level at which such decreases were effectively balanced by greater soil evaporation and less precipitation. A strong diurnal variation in the response to deforestation of ground and lower-atmosphere temperatures and heat fluxes was also identified for the summer season. The February simulations showed the effects of deforestation during low-insolation months to be small and variable. The strong response of the summer land surface-atmosphere system to deforestation shown here suggests that land cover changes can appreciably affect regional climates. Thus, the role of human-induced and naturally occurring land cover variability should not be ignored in the attribution of climate change.

Evaluating the Climate Effects of Reforestation in New England Using a Weather Research and Forecasting (WRF) Model Multiphysics Ensemble

“…Farmland abandonment and alternative fuel sources (e.g., coal) led to extensive reforestation in the New England region through the mid-1900s (Baldwin 1942;Foster et al 2008). Klingaman et al (2008) used the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) in central and northern Pennsylvania, replacing presettlement evergreen needleleaf forest with barren and sparse land cover to evaluate climate responses to deforestation in five 1-month February (2000-04) simulations. Currently, New England forest cover is around 75% (Fig.…”

“…Recently, forest cover in New England has again begun to decline, primarily due to urban and suburban development and mechanical disturbance (e.g., clear cutting; Barnes and Roy 2008). The mean difference in albedo between the Klingaman et al (2008) forested and deforested scenarios was 0.15, whereas observational studies indicate that the difference between forest and open land snow-covered albedo is closer to 0.45 (e.g., Jin et al 2002;Betts and Ball 1997;Robinson and Kukla 1984). 1b).…”

“…1b). Furthermore, only one land surface model (LSM), the Noah LSM, was used in the Klingaman et al (2008) study. Klingaman et al (2008) used the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) in central and northern Pennsylvania, replacing presettlement evergreen needleleaf forest with barren and sparse land cover to evaluate climate responses to deforestation in five 1-month February (2000-04) simulations.…”

Impacts of forest harvest on cold season land surface conditions and land‐atmosphere interactions in northern Great Lakes states

“…The results are consistent with a conceptual understanding of the impacts of forest harvest on the climate system in middle and high latitudes, specifically the cooling effect of exposed snow surfaces in winter [ Snyder et al ., ; Bonan , ]. Our high‐resolution experimental results at the local scale are also consistent with large‐scale simulations of deforestation impacts obtained using coarser modeling grids [ Snyder et al ., ; Gibbard et al ., ; Bala et al ., ; Klingaman et al ., ; Mishra et al ., ]. In extending such modeling capability to landscape‐scale and stand‐scale forest dynamics, we provide further support for the use of remote sensing‐based land cover change data in numerical analysis of land‐atmosphere fluxes and energetic balance.…”

Homogenisation of climate time series from ICP Forests Level II monitoring sites in Germany based on interpolated climate data

“…the distance of the sensors to the forest edge should be considered as a component of the metadata. The influence of the environment on weather station based measurements has been widely discussed (Gallo et al, 1996;Peterson, 2003) and especially forests have an impact on local climate (Bala et al, 2007;Klingaman et al, 2008;O'Neal et al, 2009;Strack et al, 2008). Moreover, weather station measurements in forested environments are underrepresented in national meteorological networks in industrialized countries.…”