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Outdoor Universal Thermal Comfort Index Climatology for Alaska  [PDF]
Nicole M？lders
Atmospheric and Climate Sciences (ACS) , 2019, DOI: 10.4236/acs.2019.94036
Abstract: Data from 456 surface meteorological sites in Alaska, eastern Russia and northwest Canada for 1979-2017 were used to model hourly universal thermal comfort indices (UTCIs) under consideration of Alaska-appropriate clothing. The results served to determine a high-resolution climatology of thermal comfort levels for Alaska at various temporal and spatial scales as well as the frequency of thermal stress levels. On 1979-2017 average, various degrees of cold stress occurred with highest percentage on the Alaska West Coast and along the Arctic Ocean. In the continental and Inside Passage region, no thermal stress had the highest percentage of occurrence. In Interior Alaska, both strong heat and extreme cold stress occurred occasionally. At most sites and in all Alaska Köppen-Geiger bio-climate regions, the absolute range between monthly means of daily minimum and maximum UTCIs was larger than that of monthly means of daily minimum and maximum air temperatures. Major contributors to thermal discomfort (shortwave radiation, air temperature, moisture, wind speed) varied among bio-climate regions and in the diurnal and annual courses.
Anticipated Inversion and Visibility Conditions over Glacier Bay with a Changing Climate  [PDF]
Nicole M？lders, Scott Gende
Journal of Environmental Protection (JEP) , 2015, DOI: 10.4236/jep.2015.65048
Abstract: A RCP4.5 simulation from the Community Earth System Model was downscaled by the Weather Research and Forecasting Model, inline coupled with chemistry, to examine how climate change may affect inversions and visibility in Glacier Bay in the presence of cruise-ship visitations. Mean downscaled climate conditions for the tourist seasons for 2006-2012 were compared with downscaled conditions for 2026-2032 with identical cruise-ship entries and operating conditions thereby isolating pollutant retention and visibility differences caused by atmospheric climate change. Notable changes in future temperature, humidity, precipitation, and wind-speed occurred for large areas of Southeast Alaska and the Gulf of Alaska, although the anticipated differences were less pronounced in Glacier Bay due to the presence of the large glaciers and ice fields. While increased sensible heat and water vapor in the atmospheric boundary layer contributed to on average 4.5 h reduced inversion duration in Glacier Bay, the on average 0.23 m·s-1 reduced wind speeds increased inversion frequency by 4% on average. The future on average wetter conditions and altered precipitation patterns in Glacier Bay affected the removal of gases and particulate matter emitted by cruise ships locally or advected from areas outside the park. Season-spatial averaged visibility in Glacier Bay remained the same. However, visibility was degraded in the future scenario later in the season and slightly improved during spring. The warmer conditions contributed to decreased visibility indirectly by tieing up less NO2 in PAN and increasing biogenic NOx emissions. The wetter conditions contributed to reduced visibility in the last third of the tourist season.
Impacts of Cruise-Ship Entry Quotas on Visibility and Air Quality in Glacier Bay  [PDF]
Nicole M？lders, Scott Gende
Journal of Environmental Protection (JEP) , 2015, DOI: 10.4236/jep.2015.611109
Abstract: Managers at Glacier Bay National Park must annually determine the allowable number of cruise-ship entries into the park. This decision considers how differences in visitor volume may affect park resources. This study quantified the impacts to air quality and visibility under different ship quotas using simulations with the Weather Research and Forecasting model inline coupled with chemistry. Results of the simulation assuming two entries per day for May 15 to September 15, 2008 (QTA; 248 ship entries representing a 35% increase) were compared to those of the 2008 cruise-ship activity (REF; 184) during that timeframe. A simulation without anthropogenic emissions (CLN) served to assess the overall impacts of cruise-ship emissions on visibility and air quality in Glacier Bay. Compared to REF, the increased entry quotas shifted chemical regimes and aerosol composition, depending upon thermodynamical conditions, and ambient concentrations. On days with notable regime shifts, sulfur-dioxide concentrations deceased while ammonium-sulfate aerosol concentrations increased. The increased quotas also altered the fine-to-coarse aerosol ratios in both directions despite constant ratio of fine-to-coarse aerosol emissions. In Glacier Bay, the days with worst visibility coincided with high relative humidity, although this relationship varied by scenario. On the 20% worst days, mean visibility was slightly better in CLN (mean haze index over Glacier Bay waters = 2.9 dv) than in REF ( = 3.1 dv). While increased emissions in QTA reduced mean visibility by 0.1 dv, the 10th, 50th and 90th percentile of haze indices remained identical to those in REF. Best (worst) visibility occurred on the same days in REF and QTA due to emission impacts, but on different days than in CLN because relative humidity solely governed visibility in CLN. While calm wind played no role for visibility in CLN, wind speed gained similar importance for visibility as relative humidity in REF and QTA. Overall, increasing ship quotas would only marginally affect air quality and visibility as compared to REF, although even small changes in these parameters need careful consideration in the context of conserving the values of Glacier Bay.
On the Limits to Manage Air-Quality in Glacier Bay  [PDF]
Nicole M？lders, Scott Gende
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.712151
Abstract: In Glacier Bay National Park, about 95% of the visitors come on board of cruise ships. The National Park Service has the mandate to manage park resources like air quality and visibility, while ensuring visitation. To understand the impact of cruise-ship emissions on the overall concentrations in Glacier Bay, emission-source contribution ratios (ESCR) and the interaction of pollutant from local and/or distant sources were determined using results from four WRF/Chem simulations of the 2008 tourist season (May 15 to September 15). These simulations only differed by the emissions considered: Biogenic emissions only (CLN), biogenic plus activity-based cruise-ship emissions (REF), biogenic plus all anthropogenic emissions except cruise-ship emissions (RETRO), and all aforementioned emissions (ALL). In general, ESCRs differed among pollutants. Interaction between pollutants from cruise-ship emissions and species from other sources including those advected into the bay decreased towards the top of the atmospheric boundary layer. Pollutants from different sources interacted strongest (lowest) in the west arm of the fjord where ships berthed for glacier viewing (in areas of the bay without cruise-ship travel). Pollutant interaction both enhanced/reduced NO2 concentrations by 10% (4 - 8 ppt absolute). Except for ozone, cruise-ship emissions on average governed air quality in the bay. On days with cruise-ship visits, they contributed between 60% and 80% of the bay-wide daily mean SO2 and NO2 concentrations below 1 km height. On days without visits, cruise-ship contributions still reached 40% due to previous visits. Highest cruise-ship ESCRs occurred during stagnant weather conditions. Despite the fact that all coarse particulate matter was due to anthropogenic sources, worst visibility conditions were due to meteorology. The results suggest limits as well as windows for managing air quality and visibility in Glacier Bay.
Climatology of Air Quality in Arctic Cities—Inventory and Assessment  [PDF]
Nicole M？lders, Gerhard Kramm
Open Journal of Air Pollution (OJAP) , 2018, DOI: 10.4236/ojap.2018.71004
Abstract: Freely available data of sulfur dioxide (SO2), ammonia (NH3), nitrogen dioxide (NO2), ozone (O3), and particulate matter (PM) observed in Arctic cities (north of 59.99 N) between 1972 and 2016 were compiled into an air-quality inventory of samples taken for limited periods. For cities with multiple years of data, air-quality climatology was determined in terms of daily means in the annual course. Mean urban air-quality climatology was calculated for regions of similar insolation, emission standards, topography, Köppen-Geiger classification, and city size. Urban concentrations of PM precursors (SO2, NH3, NO2), PM2.5 and PM10 (PM with diameter less than 2.5 and 10 μm) were assessed in the sense of climatology with evidence from current knowledge. Typically, annual SO2 and NO2 means were lower for small than large Arctic cities, but can vary more than an order of magnitude over short distance. Cities seeing seasonal sea-ice had W-shaped mean annual courses of daily O3, while other cities had a spring maximum. Typically, annual means of urban pollutants in North America exceeded those in Scandinavia except for O3, where the opposite was true. Annual mean urban PM2.5 and PM10 concentrations varied from 1.6 to 21.2 μg·m-3 and 2 to 18.2 μg·m-3, respectively. Since PM10 encompasses PM2.5, annual PM10 means must be at least 21.2 μg·m-3. According to rural-to-urban ratios of species, seasonal transport of pollutants from
Using MAN and Coastal AERONET Measurements to Assess the Suitability of MODIS C6.1 Aerosol Optical Depth for Monitoring Changes from Increased Arctic Shipping  [PDF]
Nicole M？lders, Mariel Friberg
Open Journal of Air Pollution (OJAP) , 2020, DOI: 10.4236/ojap.2020.94006
Abstract: Collocated data of the moderate resolution imaging spectroradiometer (MO-DIS) Collection 6.1 aerosol optical depths (AOD) at 3 km × 3 km north of 59.9°N over ocean were assessed at 550 nm by aerosol robotic network (AERONET) data from coastal sites and marine aerosol network (MAN) data from vessels during June to October 2006 to 2018. Typically, MODIS AOD was higher at low and lower at high values than the AERONET AOD. Discrepancies were largest for sites where the Earth’s surface around the site is very heterogeneous (Canadian Archipelago, coast of Greenland). Due to the higher likelihood for sea-ice, MAN and MODIS AOD differed stronger west of Greenland and over the Beaufort Sea than at location in the Greenland and Norwegian Seas and Atlantic. MODIS AOD well captured the inter-seasonal variability found in the AERONET AOD data (R = 0.933). At all sites, MO-DIS and AERONET AOD agreement improved as time progressed in the shipping season, hinting at errors in sea-ice vs. open water classification. Overall 75.3% of the MODIS AOD data fell within the limits of the error envelops of the AERONET/MAN AOD data with MAN ranging between 87.5% and 100%. Changes in both MODIS and AERONET mean AOD between two periods of same length (2006-2011, 2013-2018) were explainable by changes in emissions for all sites.
Fate of Particulate Matter from Cruise-Ship Emissions in Glacier Bay during the 2008 Tourist Season  [PDF]
Michael Pirhalla, Scott Gende, Nicole M？lders
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.512118
Abstract: Simulations from the Weather Research and Forecasting Model, inline coupled with chemistry, were used to examine the fate of particulate matter with diameter of 10 μm or less (PM10) in Glacier Bay, Alaska during the 2008 tourist season. The simulations demonstrated that mesoscale and synoptic scale weather systems affect the residence time of PM10, the magnitude of concentrations, and its transport in and out of Glacier Bay. Strong inversions exceeding 2 K (100 m)-1 cause notable trapping of pollutants from cruise-ship emissions, increasing PM10 concentrations up to 43% compared to days with cruise-ship visits without the presence of an inversion. Inversions occurred locally in Glacier Bay on 42% of the 124-day tourist season with an average lifetime of 9 h. Pollutants occasionally originated from outside the National Park when southerly winds advected pollutants from ship traffic in Icy Strait. Occasionally, orographically forced lifting over the Fairweather Mountains transported pollutants from the Gulf of Alaska into Glacier Bay. While hourly (daily) PM10 concentrations reached ~44 μg·m-3 (22 μg·m-3) in some areas of Glacier Bay, overall seasonal average PM10 concentrations were below 2 μg·m-3. Despite up to two cruise-ship visits per day, Glacier Bay still has pristine air quality. Surface and upper air meteorological state variables were evaluated through an extensive network of surface and radiosonde observations, which demonstrated that the model was able to capture the meteorological conditions well.
Using Earth’s Moon as a Testbed for Quantifying the Effect of the Terrestrial Atmosphere  [PDF]
Gerhard Kramm, Ralph Dlugi, Nicole M？lders
Natural Science (NS) , 2017, DOI: 10.4236/ns.2017.98026
Abstract: In the past, the planetary radiation balance served to quantify the atmospheric greenhouse effect by the difference between the globally averaged near-surface temperature of \"\" and the respective effective radiation temperature of the Earth without atmosphere of \"\" resulting in \"\". Since such a “thought experiment” prohibits any rigorous assessment of its results, this study considered the Moon as a testbed for the Earth in the absence of its atmosphere. Since the angular velocity of Moon’s rotation is 27.4 times slower than that of the Earth, the forcing method, the force-restore method, and a multilayer-force-restore method, used in climate modeling during the past four decades, were alternatively applied to address the influence of the angular velocity in determining the Moon’s globally averaged skin (or slab) temperature, \"\". The multilayer-force-restore method always provides？the highest values for \"\", followed by the force-restore method and the forcing method, but the differences are marginal. Assuming a solar albedo of \"\", a relative emissivity \"\", and a solar constant of \"\" and applying the multilayer-force-restore method yielded \"\" and \"\" for the Moon. Using the same values for α, ε, and S, but assuming the Earth’s angular velocity for the Moon yielded \"\" and \"\" quantifying the effect of the terrestrial atmosphere by \"\". A sensitivity study for a solar albedo of \"\" commonly assumed for the Earth
Review of Black Carbon in the Arctic—Origin, Measurement Methods, and Observations  [PDF]
Nicole M？lders, Stanley G. Edwin
Open Journal of Air Pollution (OJAP) , 2018, DOI: 10.4236/ojap.2018.72010
Abstract: Current knowledge about black carbon (BC) emission estimates, state-of-the-art measurement methods, near-surface BC concentrations ([BC]), and mixing ratios in snow is consolidated for the Arctic. Since no direct method exists to measure [BC], results from modern indirect methods differ among devices. Pan-Arctic wide [BC] and changes are hard to access; monitoring often ends once national ambient air quality standards are met. Few remote sites have long records. Past measurements showed distinct differences among the various Arctic climate regions. Past and own observations in communities permit qualitative discussion of the diurnal course, response to weather, season, or different emission situations like weekdays and weekends at a given site and/or among sites. Comparison of data from collocated aethalometer indicated more similar accuracy than found in mid- and low-latitudes despite of much lower ambient temperatures and [BC]. Snow samples give an incomplete glimpse at the removal and input into ecosystems.
Particulate Matter Exposure of Rural Interior Communities as Observed by the First Tribal Air Quality Network in the Yukon Flat  [PDF]
Stanley G. Edwin, Nicole M？lders
Journal of Environmental Protection (JEP) , 2018, DOI: 10.4236/jep.2018.913088
Abstract: A tribal-owned network of aerosol monitors and meteorological stations was installed at Ts’aahudaaneekk’onh Denh (Beaver), Gwichyaa Zheh (Fort Yukon), Jalgiitsik (Chalkyitsik), and Danzhit Khànlaii (Circle) in the Yukon Flats, Alaska. Surface inversions occurred under calm wind conditions due to radiative cooling. In May, local emissions governed air quality with worst conditions related to road and river dust. As the warm season progressed, worst air quality was due to transport of pollutants from upwind wildfires. During situations without smoke or when smoke existed at layers above the surface inversion, concentrations of particulate matter of less than 2.5 micrometer in diameter or less (PM2.5) were explainable by the local emissions; 24-h means remained below 25 μg·m-3. Absorption of solar radiation in the smoke layer and upward scattering enhanced stability and fostered the persistence of the surface inversions. During smoke episodes without the presence of a surface inversion, daily mean concentrations exceeded 35 μg·m-3 often for several consecutive days, at all sites. Then concentrations temporally reached levels considered unhealthy.
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