Deforestation in the New England region of the United States peaked around 1850, with almost 50% of the total land area cleared for pasture, lumber and timber, agriculture, and home heating. Farmland abandonment in the late-1800's led to reforestation and today New England is the most forested region in the US. This dissertation explores the hypothesis that mid-1800's deforestation led to cooler winters for two reasons: (1) increased surface albedo, a measure of surface reflectivity, and (2) decreased surface roughness length. Three chapters detail: a scaling approach to assess accuracy of albedo over forested and deforested landscapes in New Hampshire (Chapter I); the establishment of a volunteer albedo observer network to characterize albedo over deforested landscapes (Chapter II); and the validation of a regional climate model to simulate historical climate responses to deforestation (Chapter III). The results from Chapter I and II provide essential validation data for the regional climate model in Chapter III.
The scaling approach shows that albedo over deforested lands is underestimated at wavelengths less than 450 nm and that tower-, airborne-, and satellite-based albedo over forests are relatively consistent across spatial scales. The regional climate model overestimates the albedo of snow-covered deciduous broadleaf forests, which may be a strong contributor to cold biases in November through January maximum temperature (TMAX) identified in the climate model.
The modeling approach suggests that mid-1800's deforestation resulted in daytime cooling in the New England region. The impact on nighttime temperatures remains unclear because the model was not able to capture observed nighttime cooling patterns associated with surface roughness and atmospheric stability over open lands. 1 conclude that mid-1800's deforestation in New England contributed to cooler winters, however the magnitude of cooling at night requires improvements to snow-surface coupling in the regional climate model.
|School:||University of New Hampshire|
|School Location:||United States -- New Hampshire|
|Source:||DAI-B 75/06(E), Dissertation Abstracts International|
|Subjects:||Atmospheric sciences, Environmental science|
|Keywords:||Albedo, Climate, Deforestation, New England, Snow|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be