Climate Change and Air Pollutant Impacts to New England’s Rare Alpine Zone

Observatory researchers, in collaboration with the Appalachian Mountain Club (AMC) and Plymouth State University (PSU), are assessing climate and air pollutant trends and their influence on New England’s high-elevation alpine ecosystems. With support from the National Oceanic and Atmospheric Administration, this work is built upon the Observatory’s climate record and remote observational systems, as well as the AMC’s air quality and alpine ecosystem monitoring.

In order to quantify the climatological controls on the alpine zone, a major focus of the Observatory’s partnership with the AMC is the creation and analysis of a regional dataset of high elevation temperature and snow observations. These data are primarily those collected by AMC and Randolph Mountain Club staff at backcountry huts in the White Mountain National Forest.

Another major focus of this project is the expansion of the measurements made at Mount Washington Regional Mesonet sites. These sites are located at several points along the Mt. Washington Auto Road and at ski area summits, mountain peaks and AMC huts throughout the Presidential Range.

This project was designed as a three-year project to specifically study climate and air pollution in New Hampshire’s Presidential Range. The initial working hypotheses were that northeastern U.S. sub-alpine and alpine ecosystems:

  • Are exposed to higher pollutant regimes than surrounding lower elevations
  • Would exhibit climatic warming trends similar to those reported for the surrounding lower elevations of the region, and
  • Are susceptible to rapid depletion or extinction, because being isolated biogeographic islands they a) can not “migrate upwards” to escape a warming climate as they are already limited to the region’s higher peaks, and b) are exposed to higher levels of air pollution.

As we and others have documented, ozone exhibits greater levels at or above the planetary boundary layer on the mountain (Fischer et al. 2004). Fine particulate sulfate aerosol concentrations at higher elevations on the mountain, however, are statistically less compared to levels measured at the base of the mountain, but the high elevation samples are compromised of relatively more acidic sulfate aerosols (Murray et al. 2009).

Our climatic analysis challenged our second hypothesis. Though trending warmer, we found no statistically significant temperature trends over the period of record (past seven decades) at the higher elevations, unlike the surrounding lower elevations. Our results (Grant et al. 2009; Seidel et al. 2009) correct an earlier paper on climatic warming on Mount Washington (Grant et al. 2005). Our results contrast with the predictions commonly suggested in the literature that the northeast’s sub-alpine and alpine ecosystems are immediately threatened by and are rapidly undergoing warming.

The elevation of the regions planetary boundary layer and cloud base, and its relationship with the sub-alpine and alpine ecosystems, offers insight into why the higher mountain elevations may be partially uncoupled from the climatic trends observed at lower elevations in the region. And related factors such as snow cover, wind and cloud exposure, particularly in the winter that can cause mechanical degradation from icing, are possibly as or more important than temperature in determining these mountain ecosystems future viability. We plan to better understand these important parameters in future projects.

Fischer, E.V., R. W. Talbot, J. E. Dibb, J. L. Moody, and G. L. Murray. 2004. Summertime ozone at Mount Washington: Meteorological controls at the highest peak in the northeast. J. of Geophysical Res. 109: D24303, 15 pp.

Grant, A.N., A.A.P. Pszenny and E.V. Fischer. 2005. The 1935-2003 air temperature record from the summit of Mount Washington, New Hampshire, USA, J. Climate, 18, 4445 4453.

Grant, A.N., Pszenny, A.P., and Fischer, E.V.. 2009. Corrigendum. J. Climate, 22: 1065- 1066.

Murray, G., Kimball, K., Hill, L.B., Allen, G.A., Wolfson, J.M., Pzenny, A., Seidel, T., Doddridge, B.G., and Alexandra, B. 2009. A comparison of fine particle and aerosol strong acidity at the interface zone (1540 m) and within (452 m) the planetary boundary layer of the Great Gulf and Presidential-Dry River Class I Wildernesses on the Presidential Range, New Hampshire US. Atmospheric Environment 43:3603-3613.

Seidel, T.M., Weihrauch, D., Kimball, K.D., Pszenny, A., Soboleskil, R., Crete, E. and G. Murray. 2009). Evidence of climate change declines with elevation based on temperature and snow records from 1930s to 2006 on Mount Washington, New Hampshire, USA. Arctic, Antarctic, and Alpine Research 41:362-372.