Kenneth D. Kimball

Two new ground-level cloud water sampler designs which reduce rain contamination

Abstract The ability to obtain discrete samples of cloud water for chemical analysis during periods when precipitation is occurring is important for studies of potential ecological effects of cloud and rain deposition. The advantage of the two cloud water collector designs presented, over others reported in the literature, is their ability to greatly reduce the entry of horizontally blown drizzle and rain droplets (> 200 μm) into the collector. The CWP Active Cloud Water Collector can be used in either stagnant or windy environments and requires 12 V battery power. The AMC/WPI Passive Cloud Water Collector is designed for windy environs and requires no power. Both collectors use removable cartridges with Teflon strands as a collection surface, and collect cloud droplets by inertial impaction. On Mount Washington, NH, the Active and Passive Cloud Water Collectors had an average cloud water collection rate of 1.8 and 1.5 ml min−1, respectively.

Differences between new england coastal fog and mountain cloud water chemistry

Major inorganic ions and pH were analyzed from mountain cloud and coastal fog water event samples from New Hampshire and Maine, U.S.A. Based on marine corrected values, the medians for coastal fog were still up to three times higher in ionic concentrations and lower in pH, compared to mountain clouds. Of the acidic constituents, nitrate concentrations were considerably higher in coastal fogs, which correlates with higher concentrations of 03 measured along the New England coast. It is hypothesized that meteorological conditions permit air pollutants emitted in the northeastern US urban corridor to move relatively intact across the Gulf of Maine and to interact with the coastal fogs, which results in differences in the chemistry of coastal fogs and mountain clouds.

Evidence of Climate Change Declines with Elevation Based on Temperature and Snow Records from 1930s to 2006 on Mount Washington, New Hampshire, U.S.A.

Abstract Mount Washington, New Hampshire, has the longest northeastern U.S. mountain climatological record (1930s to present), both at the summit (1914 m) and at Pinkham Notch (612 m). Pinkhams homogenized daily temperature exhibits annual (mean  =  +0.07°C/decade, p  =  0.07; min  =  +0.11°C/decade, p  =  0.01), winter (min  =  +0.18°C/decade, p  =  0.07), spring (max  =  +0.13°C/decade, p  =  0.10), and summer (min  =  +0.11°C/decade, p  =  0.01) warming trends. Though suggesting annual, winter, and spring warming (0.05 to 0.12°C/decade), mean summit temperature trends were not significant. Pinkham shows no significant change in date of first and last snow; however, the summit does but its period of record is shorter. Onset of continuous snow cover has not changed significantly at either site. Thawing degree days trended earlier at the summit (2.8 days/decade; p  =  0.01) and Pinkham Notch (1.6 days/decade, p < 0.01), but end of continuous snow cover trended significantly earlier (1.6 days/decade; p  =  0.02) only at Pinkham. Growing degree days showed no significant trends at either location. Pinkham exhibits more climatic change than the summit but less than regional lower elevations. Thermal inversions and high incidence of cloud fog commonly at or above the regional atmospheric boundary layer may explain the summits resistance to climate warming. Caution is needed when extrapolating climate change trends from other mountains or proximate lower elevation climate data to upper elevations.

Chemical Concentrations in Cloud Water from Four Sites in the Eastern United States

Event samples of cloud and fog water were collected in 1984 and 1985 as part of the Cloud Water Project, a large-scale network designed to chemically analyse cloud and rain water from ten sites in North America. The data presented here are from four sites in the eastern United States that ranged in elevation from 5 m to 1534 m, and in geographic location from Virginia to Maine.

Limited alpine climatic warming and modeled phenology advancement for three alpine species in the Northeast United States

UNLABELLED • PREMISE OF THE STUDY Most alpine plants in the Northeast United States are perennial and flower early in the growing season, extending their limited growing season. Concurrently, they risk the loss of reproductive efforts to late frosts. Quantifying long-term trends in northeastern alpine flower phenology and late-spring/early-summer frost risk is limited by a dearth of phenology and climate data, except for Mount Washington, New Hampshire (1916 m a.s.l.).• METHODS Logistic phenology models for three northeastern US alpine species (Diapensia lapponica, Carex bigelowii and Vaccinium vitis-idaea) were developed from 4 yr (2008-2011) of phenology and air temperature measurements from 12 plots proximate to Mount Washingtons long-term summit meteorological station. Plot-level air temperature, the logistic phenology models, and Mount Washingtons climate data were used to hindcast model yearly (1935-2011) floral phenology and frost damage risk for the focal species.• KEY RESULTS Day of year and air growing degree-days with threshold temperatures of -4°C (D. lapponica and C. bigelowii) and -2°C (V. vitis-idaea) best predicted flowering. Modeled historic flowering dates trended significantly earlier but the 77-yr change was small (1.2-2.1 d) and did not significantly increase early-flowering risk from late-spring/early-summer frost damage.• CONCLUSIONS Modeled trends in phenological advancement and sensitivity for three northeastern alpine species are less pronounced compared with lower elevations in the region, and this small shift in flower timing did not increase risk of frost damage. Potential reasons for limited earlier phenological advancement at higher elevations include a slower warming trend and increased cloud exposure with elevation and/or inadequate chilling requirements.