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The primary mission of AIRMAP, which is based at the University of New Hampshire's Climate Change Research Center, is to develop a detailed understanding of climate variability and the source of persistent air pollutants in New England, to identify the causes of climate variability, predict air quality changes as an addition to daily weather forecasts, and to demonstrate new forecasting technologies. AIRMAP is supported by NOAA's Office of Oceanic and Atmospheric Research. The Observatory makes several contributions to AIRMAP:

The Summit Crew monitors the AIRMAP air quality measurement instrumentation on the summit.

Our Staff Scientists have published studies of summertime ozone, multi-year aerosol ionic composition variations, aerosol acidity, and unusual winter aerosol composition events.

We are currently analyzing the summit climate record for evidence of trends. We have digitized Mount Washington hourly and six-hourly climate data, with a continuous record starting in 1935. These data provide better temporal resolution than the daily summary data that are available from the National Climate Data Center. Recent and current work focuses on quality control for digitization errors and analyzing the hourly data.

To date the analysis has focused on long term trends in temperature and humidity. These data sets are unique due to both their long record length and consistent instrumentation. Most U.S. weather and climate stations have changed instruments or location within the last 70 years.

An analysis of the 1935-2003 temperature data (Grant et al [2005]) showed a statistically significant warming of 0.32 C (0.58F) in annual average temperature. During this 69 year period the winter and spring average temperatures warmed more than the annual average, 0.71C (1.3F) and 0.80C (1.4F) respectively. Summer and fall had no significant trends. The difference between daily minimum and maximum temperatures has decreased during this period (Figure 1). These results are consistent with temperature observations across New England.

Figure 1. Annual and Diurnal Timeseries
chart - see caption below - click to enlarge
(a) Mean temperature and (b) diurnal temperature range, with linear regressions, for the 69-yr record from max.min (black) and hourly (red) datasets. Max.min (hourly) mean temperature has increased by 0.31°C (0.32°C); diurnal range has decreased by 0.14°C (0.16°C).

Seidel et al. [Journal of Climate, in press] presents a climatology of humidity measurements (dew point, relative humidity, and water vapor mixing ratio) created using 1935-2004 data. This climatology includes annual, seasonal, day, night, fog, and clear-air averages. In addition, trend analysis shows, with seasonal and diurnal variation, that Mount Washington humidity has decreased over the full study period, especially during clear-air periods (Figures 2&3). These results are unique compared to those from previous studies, as most observations of humidity show an increase. However, those studies generally are restricted to the last two or three decades, suggesting that the disparity is mostly due to length of record. Indeed, the Mount Washington record shows increasing trends in the past ~30 years.

Figure 2. Winter C-A Dew Point Timeseries
chart - see caption below - click to enlarge
All (solid line) and clear-air (dashed line) winter dew point temperature, 1935-2004, with linear regressions.


Figure 3. All Dew Point Trends in Table Form chart - see caption below
Dew point temperature decadal trends for 1939-2004. Starting from the top row the figure shows a) all, b) fog, c) clear-air, d) clear-day, e) clear-night, f) day, and g) night classes. Gray (black) shading indicates 5% (1%) significance.
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Eric Kelsey, Director of Research
(603) 535-2271

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